research article optimal overcurrent relay coordination...
TRANSCRIPT
Research ArticleOptimal Overcurrent Relay Coordination Using OptimizedObjective Function
Seyed Hadi Mousavi Motlagh12 and Kazem Mazlumi1
1 Electrical Engineering Department University of Zanjan Zanjan 45371-38791 Iran2 Zanjan Regional Electric Company Zanjan 33685-45137 Iran
Correspondence should be addressed to Kazem Mazlumi kmazlumiznuacir
Received 8 January 2014 Accepted 9 March 2014 Published 3 April 2014
Academic Editors L D S Coelho B Li and H Torkaman
Copyright copy 2014 S H Mousavi Motlagh and K Mazlumi This is an open access article distributed under the Creative CommonsAttribution License which permits unrestricted use distribution and reproduction in any medium provided the original work isproperly cited
A novel strategy for directional overcurrent relays (DOCRs) coordination is proposed In the proposed method the objectivefunction is improved during the optimization process and objective function coefficients are changed in optimization problemTheproposed objective function is more flexible than the old objective functions because various coefficients of objective function areset by optimization algorithmThe optimization problem is solved using hybrid genetic algorithm and particle swarm optimizationalgorithm (HGAPSOA) This method is applied to 6-bus and 30-bus sample networks
1 Introduction
Protection of distribution networks is one of themost import-ant issues in power systems Overcurrent relay is one ofthe most commonly used protective relays in these systemsThere are two types of settings for these kinds of relays cur-rent and time settings A proper relay setting plays a crucialrole in reducing undesired effects of faults on the power sys-tems [1 2] Overcurrent relays commonly have plug setting(PS) ranging from 50 to 200 in steps of 25 The PS showsthe current setting of the overcurrent relays For a relayinstalled on a line PS is defined by two parameters the mini-mum fault current and the maximum load current Howeverthe most important variable in the optimal coordination ofovercurrent relays is the time multiplier setting (TMS) [3]
So far some researches have been carried out on coor-dination of overcurrent relays [3ndash7] Due to the difficulty ofnonlinear optimal programming techniques the usual opti-mal coordination of overcurrent relays is generally carried outby linear programming techniques including simplex two-phase simplex and dual simplex methods [3] In these meth-ods the discrimination time of the main and backup relays(Δ119905mb) are considered as constraints and then the optimalcoordination problem is solved using both objective function
and constraints In [8] a fast method for optimization of theTMSs and current settings by evolutionary algorithm andlinear programming has been proposed In [4] an onlinetechnique to estimate the setting of DOCRs is introducedThis technique is based on estimation of parameters of aproper equivalent circuit of the grid Relay coordinationwhich is very constrained discrete optimization problem ishardly solved by traditional optimization techniques [5] In[9] the pickup current and the TMS of the relays have beenconsidered the optimization parameters for optimal coordi-nation of directional overcurrent relays These optimizationtechniques are started by an initial conjecture and are possiblytrapped in a local optimum [3] The intelligent optimizationtechniques have come up in such a way that can adjustthe settings of the relays without the mentioned problemsIn these methods the constraints are considered a part ofobjective function In [6] a developed method based ongenetic algorithm (GA) for optimal coordination has beenproposed this method has not considered the main principleof the coordination So there may be some miscoordinationin the settings of the relays As a result of themiscoordinationwhen a fault occurs in front of the main relays some backuprelaysmay operate faster than themain oneThis causesmorelines of network to go out due to the occurring faults in some
Hindawi Publishing CorporationISRN Power EngineeringVolume 2014 Article ID 869617 10 pageshttpdxdoiorg1011552014869617
2 ISRN Power Engineering
parts of the network Obviously in this case the number ofinterrupted customers increases and consequently the powerquality declines
In [10] continuous genetic algorithm has been usedin a ring fed distribution system for optimal coordinationof overcurrent relays In [11] an objective function hasbeen proposed in which the problem of miscoordinationhas almost been solved The objective function of [11] canprevent the appearance of inappropriate results which makemiscoordination Suitable parameter initializing has beenconsidered in the objective function of the paper that weightsboth the time and the delay time of the backup relays Themain shortcoming of the objective function of [11] is thatsomeof the coefficients of objective function are set by try anderror It is proved by experience that using such coefficientscannot guarantee accessing to the smallest operation time ofthe relays In some cases using inappropriate parameters inobjective function may result in some miscoordination
In this paper a new method for directional overcurrentrelay coordination is proposed in which not only the misco-ordination is omitted but also operation times of the relaysare the smallest This is because in this novel algorithmthe coefficients of the previous proposed objective functionare considered a part of the optimization problem So thecoefficients of the objective function are not constant andthey are not set by try and error In the proposed methodthe coefficients are calculated based on the optimizationtechnique The optimization problem of this paper is solvedusing a hybrid genetic and particle swarm optimizationalgorithmThismethod is applied to 6-bus and 30-bus samplenetworks The results of this method are compared with theresults of the existing ones The simulation results and thecomparisons demonstrate the effectiveness and the advantageof the proposed algorithm
2 Hybrid GA and PSO (HGAPSO) inRelay Coordination Application
By incorporating the GA into the PSO the novel HGAPSOalgorithm is obtained [12]TheHGAPSOA can provide betterresults [13] In this algorithm the initial population of GAis assigned by the solution of PSO The total numbers of theiterations are equivalently shared by GA and PSO First halfof the iterations are carried out by PSO and the solutionsare given as initial population of GA [14] In this section webriefly discuss the application of HGAPSOA in overcurrentrelay coordination According to Figure 1 at first the userinitializes the information such as algorithm parameters(population size iteration numbers mutation and crossoverrange) relay data and network data The HGAPSOA basicsin coordination of the DOCRs are described in 4 steps
Step 1 Initial Generation A number of random particles areproduced The variables of HGAPSOA are the TMSs of theDOCRs and the coefficients of the objective function Inour problem the number of the variables is equal to thenumber of the relays and the number of the objective functioncoefficients The TMSs are randomly generated between 005and 1
Step 2 Evaluate the Objective Function In this step the valueof the objective function is calculated for every gene anddiscerns between good and bad chromosomes
Step 3 PSO Operators In PSO box update the local bestposition experienced by every particle denoted as 119901best andupdate the best position experienced by whole particlesdenoted as 119892best
Step 4 GA Operators The best particles are selected as theinitial population of GA In this step the objective functionevaluation is compared with its initial best chromosome(minimum value in the TMS vector) If the evaluated valueis less than the initial best chromosome set the best chromo-some equal to the evaluated value Then update the positionof the genes by using crossover and mutation operators
Finally if any of the following stopping criteria (inthis study maximum number of iterations) then go to thefollowingmoduleThismodule is used to transfer the optimalrelay TMSs calculated fromHGAPSOA through the interfacesystem to each relay
3 Problem Statement
Toprevent overcurrent relaysmiscoordination and to find theoptimum results of the objective function of [11] the novelobjective function is formulated as follows
119874 sdot 119865 = 1205721timessum(119905
119894)119872
+ 1205722
timessum(Δ119905mb minus 120573 times (Δ119905mb minus1003816100381610038161003816Δ119905mb1003816100381610038161003816))119873
(1)
where 1205721 1205722 and 120573 are weighting coefficients119872 and 119873 are
even numbers 119905119894is the operating time of 119894th overcurrent relay
when a fault occurs next to the relay Δ119905mb is the discrimina-tion time between the main and backup overcurrent relaysΔ119905mb is obtained by
Δ119905mb = 119905b minus 119905m minus CTI (2)
where 119905b and 119905m are the operating time of the backup andmainrelays when a fault occurs next to the main relay The valueof coordination time interval (CTI) is mainly chosen basedon the practical limitations which consist of the relay over-travel time the breaker operating time and the safety marginfor the relay error [15] Generally the suitable CTI is selectedbetween 02 and 05 second In this study CTI is considered tobe 03 seconds According to the proposed objective functionof [11] the weighting coefficients (120573 120572
1 1205722) are set by try and
error and also the coefficients of (119872119873) are constant andcannot guarantee accessing to the smallest operation time ofthe relays
The first term of (1) is the sum of overcurrent relaysrsquooperating time and the second term is the coordinationconstraint To describe the role of the second term of theabove object function consider that Δ119905mb must be positivethen the relative expression (Δ119905mbminus120573sdot(Δ119905mbminus|Δ119905mb|) is equalto Δ119905mb Exactly the mentioned equation if Δ119905mb is negativeis as follows
(1 + 2120573) (Δ119905mb) (3)
ISRN Power Engineering 3
Start
Algorithm parameters inputpopulation size iteration numbermutation and crossover range
Relay and network data
Initial generation
Evaluate objectivefunction
End iteration
Record outputs relay
operation times relay
Update Pbest Position update
SelectionCrossoverMutation
Update gbest
GA operators
PSO operators
End
No
Yes
TMS 1205721 1205722MN
Figure 1 Flowchart of the proposed method
If the coefficient 120573 is a large number the value of (3)is greater than the Δ119905mb and the object function results ina large value and is not selected for the next iterations inthe optimization algorithm Consequently the output resultscontain no miscoordination
4 New Method
In this paper the five coefficients of (1) that is 120573 1205721 1205722
119872 and 119873 beside TMSs are incorporated as a part ofthe optimization parameters The new objective function isshown in (1)
To understand the importance of these coefficients thefollowing notes are helpful
(i) To assure minimizing the main relay operating timea great value must be assigned to 120572
1and119872
(ii) To assure minimizing the backup relay operationtime a great value must be assigned to 120572
2and119873
(iii) To prevent miscoordination and have faster andmoreaccurate convergence choose a large value for 120573 and119873
According to the above notes it is obvious that determin-ing these five coefficients as well as the TMS of the relayswith an optimization algorithm will result in a better relaycoordination Therefore the method presented in this paperoptimizes the objective function coefficients as well as theTMSs of the relays to have a tradeoff between the fast oper-ating time and preventing miscoordination The algorithmapplied to the relays coordination optimization problemfor the proposed technique is provided in Figure 1 In thefirst step of the algorithm the initial values are randomlyguessed The initial values consist of both relayrsquos TMS andthe coefficients of the objective function The relay settingsare packed into a packet each packet is a probable result forthe optimization problem and therefore each member of apacket represents a TMS of a relay In addition there are fiveextra coefficients that should be optimized which belong tothe objective function (120572
1 1205722 120573 119872 and 119873) In the second
step the packet is evaluated by the objective function of (1)The objective function determines the value of each packetby receiving the TMS of all relays After evaluation processthe best packet is chosen from the least objective functionoutput point of view In the next step finishing criteria ofalgorithm are checked to be the limited iterations and yield a
4 ISRN Power Engineering
prespecified fitness value If one of them is satisfied then thealgorithm terminates and goes to the next stage otherwise itreturns to the second step and starts the next iteration
5 Mathematical Overcurrent Relay Models
There are many mathematical models for the overcurrentrelays In this study the mathematical model of overcurrentrelays is considered to be the standard inverse type In thismathematical model the operating time of the overcurrentrelay is expressed as follows [16]
119905 =119896 times TMS(119894sc1198940)
119899
minus 1+ 119871 (4)
where 1198680is relay current setting 119868sc is short-circuit current
119879 is the relay operating time and TMS is the time multipliersetting of the relay TMS varies from 005 to 1 From the IECcurves for standard inverse type relays the parameters of (4)are assumed to be 119871 = 0 119896 = 014 and 119899 = 002
6 Comparison of the Results and Discussion
As described in Section 4 the values of the five coefficientsare variable so the output value of the objective function willnot be an appropriate criterion for comparing results of theproposed algorithm in [11] Therefore in order to gain thisaim two indicators are defined as follows
(i) Summation of TMSs If in a set of results of relay coor-dination there is not any miscoordination betweeneach two relays it can be said that the better coordina-tion has smaller summation of TMSs and therewithrelays have lower operating times
(ii) Summation of Difference between Each Time Opera-tion (sumΔ119905mb) For comparing two sets of the coor-dination results for example result 119860 and result 119861which do not have any miscoordination if value of(5) is true then the set of result 119860 is better than 119861Consider
119899
sum
(mb)=1(Δ119905(mb)119860 minus Δ119905(mb)119861) lt 0 (5)
In (5) the number of pairs of mainbackup (m b) relaysis equal to 119899 In this paper the proposed method is applied totwo different networks namely case study 1 and case study 2(case study 1 consists of 6 buses and case study 2 is the IEEE30-bus system) which are selected
61 Case Study 1 Network and Protection Information Casestudy 1 is 6-bus network shown in Figure 2 This networkconsists of 7 lines 6 buses 2 generators 2 transformers and14 overcurrent relays [17]
All the information about this network including short-circuit current of backup and main relays and relevant infor-mation relative to mainbackup relays have been provided in[11] and also are shown in Table 1
Table 1 Mainbackup pair information
Main relay Backup relay Primary relaySC current
Backup relaycurrent
8 9 4961 4108 7 4961 15202 7 5362 15282 1 5362 8043 2 3334 33344 3 2234 22345 4 1352 13526 5 4965 4116 14 4965 152214 1 4232 79414 9 4232 4071 6 2682 26829 10 1443 144310 11 2334 233411 12 3480 348012 14 5365 152912 13 5365 80513 8 2490 24907 5 4232 4077 13 4232 794
Table 2 119868119897max information
Relay number Maximum loadcurrent Relay number Maximum load
current1 416 8 4582 666 9 4503 500 10 4584 666 11 5415 458 12 4586 458 13 5007 541 14 666
Table 3 The input parameters of the optimization algorithm
Mutate range 03Crossover range 07Number of variables 19Number of population 100Maximum iteration 200Maximum subiteration GA 10Maximum subiteration PSO 10
Table 2 shows the maximum load current passingthrough the relays The way of the relay current settings isdescribed as follows [11]
1198680= 12 times 119868
119897max (6)
ISRN Power Engineering 5
R1
R2
R3R4
R5R6R7
R8R9
R10
R11R12R13
R14
sim
sim
Figure 2 Case study 1 network
32
21 61
63
22
18
46
3
12
44
4
49
95250
5
753483
64
62
23
84
82
41
20
1659
79
5442
85 8657
7
19 8
45 6
48
47
24 6725
68
69
65
70 26
56
12733376
7774
31
30
143855
58
15
39
81
4035
36
37
78
72
13
80
71
66
29
Figure 3 IEEE 30-bus system
6 ISRN Power Engineering
Table 4 The coordination results
Coordination output Reference [11] GAPSOTMS1
015 0066TMS2
035 01833TMS3
025 0146TMS4
01 0069TMS5
01 008TMS6
025 013TMS7
02 012TMS8
025 012TMS9
005 0095TMS10
015 0135TMS11
025 0174TMS12
04 0273TMS13
01 005TMS14
015 011199051
05894 0271199052
12173 0661199053
09621 0581199054
06636 0461199055
07660 0611199056
07623 041199057
07059 0431199058
07625 0371199059
03479 06611990510
06883 06411990511
09835 07111990512
11847 08211990513
04665 02411990514
05944 043Δ11990589
0 0Δ11990587
04673 0296Δ11990527
00028 0Δ11990521
06290 0Δ11990532
02657 0Δ11990543
02057 0Δ11990554
01885 0Δ11990565
0 0Δ119905614
04825 0418Δ119905141
13181 0258Δ119905149
0 0Δ11990516
00532 0Δ119905910
03173 0Δ1199051011
02195 0Δ1199051112
00492 0Δ1199051214
00489 0Δ1199051213
08135 0065Δ119905138
02292 0Δ11990575
0 0Δ119905713
14086 0511sumΔ119905 6699 155sumTMS 275 1741
Table 5 The object function parameters
1205721 251205722 01120573 15722119872 100119873 2
Table 6 Algorithm parameters information
Mutate range 03Crossover range 08Number of variables 91Number of population 200Maximum iteration 500Maximum subiteration GA 10Maximum subiteration PSO 10
All control parameters of algorithm are listed in Table 3The number of the variables in optimization problem is 19Fourteen of the variables are related to the TMS of the relaysand the remaining five variables are the coefficients of theobjective function that is 120573 120572
1 1205722119872119873
The results of the proposedmethod by GAPSO algorithmand the best results of [11] are compared in Table 4 The bestresults of [11] are shown in the second column of Table 4Thethird column of Table 4 represents feasible results for coordi-nation of the relays using the proposed method From Table4 all Δ119905mb values are small and positive and the largest Δ119905mbis 0511 secThe results mean there is not anymiscoordinationin the results Table 4 shows two superiority indicatorsthat is sumTMS and sumΔ119905mb optimized using the proposedalgorithm The first superiority indicator (sum119879119872119878) for theresults of [11] is 275 and for the proposed method is 1741and the second superiority indicator (sumΔ119905mb) for the resultsof [11] is 6699 sec and for the proposed method is 155 secThe superiority indicators show that the results would bemore optimized when the coefficients are optimized by theproposed algorithmThe advantage of thismethod is revealedwhen this new method is compared with the result of [11] inwhich the parameters are set manually in Table 4
With attend to Table 4 more relays operating time thatare earn from proposed method are smaller than [11] Forexample 119905
2in the proposedmethod is 066 seconds and in [11]
is 12173 seconds or 11990512
in proposed method is 082 secondsand in [11] is 11847 sec Also the values of the five parametersof objective function are shown in Table 5
62 Case Study 2 Network and Protection Information Forthe other test case 30-bus IEEE network is considered Thisnetwork has 86 OC relays It consists of 30 buses (132- and33-kV buses) 37 lines 6 generators 4 transformers and86OC relays [18] The distribution section of network thatwill be studied here is shown in Figure 3 [19] The generatortransmission lines and transformer information are givenfrom [20]
ISRN Power Engineering 7
Table 7 Coordination output results
Relay number 119879 TMS1 03092 01172 03092 01173 03467 01194 02095 00685 07561 01026 05671 02277 0248 00918 07271 01899 05679 010710 06679 024511 067 024112 0423 016013 0621 019514 09412 02515 09268 017016 02343 007417 05493 013918 05749 019019 03947 010520 05669 016321 02716 005922 05094 009023 05468 013924 07716 014225 07482 021726 06391 023927 06033 020328 06351 018429 06351 018430 06358 018331 04274 008832 05374 011833 0252 009034 02694 008935 03322 008436 08262 017437 04902 010638 01732 00539 01731 006140 01627 006841 06102 012342 02748 011543 0656 02544 02103 007645 02249 008446 0397 008147 01756 005648 05501 0179
Table 7 Continued
Relay number 119879 TMS49 07792 015550 01803 006151 0654 021152 06578 016653 06173 012954 05556 009355 10366 022456 05839 014358 06095 017659 02618 006560 04635 012961 02769 005662 03095 006163 03954 006664 05534 012865 03576 009466 05278 009967 05855 009968 07435 016169 05109 009570 06543 011371 02269 007872 0477 014373 02072 007074 06521 020475 03362 010476 05226 011577 02853 007378 04494 011680 04341 013781 03934 011182 08588 015483 09303 020284 05091 007785 03488 014486 03566 0079
In this paper four different cases are simulated for asuitable comparison Three cases are simulated according tothemethod of [11] in which the objective function coefficientsare set manually and the last case is simulated according tothe method proposed in this paper in which the objectivefunction coefficients are not set before simulation and theoptimization results show the values of the coefficients Allcases are evaluated by HGAPSO algorithm and all controlparameters of algorithm are listed in Table 6 The parametersare considered the same as 4 test cases A number of variablesin new method are considered 91 86 variables for relaysnumber and 5 variables for (120573 120572
1 1205722119872119873) and for method
proposed in [11] are considered 86Firstly the results of the proposed method by GAPSOA
are shown in Tables 7 and 8 The first column of Table 7
8 ISRN Power Engineering
Table 8 Time difference for each pair of MB relays
Δ11990541
03529 Δ1199051816
00021 Δ119905344
0 Δ1199051557
0 Δ1199055671
00122Δ11990561
0 Δ1199051916
01591 Δ119905145
00337 Δ1199055557
0 Δ1199055871
00025Δ11990571
03146 Δ1199052016
0 Δ119905345
0 Δ1199051458
01002 Δ1199052672
0Δ119905451
03418 Δ1199052118
10402 Δ119905146
0 Δ1199055558
0 Δ1199052772
0Δ11990542
03529 Δ1199052319
0 Δ119905246
0 Δ119905859
0 Δ1199052872
0Δ11990562
0 Δ1199053219
00027 Δ119905647
0 Δ1199054759
05927 Δ1199053072
0Δ11990572
03146 Δ1199056419
0 Δ119905747
03238 Δ1199054859
01788 Δ1199055672
0Δ119905442
03565 Δ1199052220
05459 Δ1199054447
03147 Δ1199051860
0 Δ1199055872
0Δ11990553
0 Δ1199052321
00023 Δ1199054547
03 Δ1199051960
01665 Δ1199052673
00003Δ11990584
0 Δ1199053221
0 Δ1199054648
0 Δ1199052060
00008 Δ1199052773
0Δ119905164
056 Δ1199056221
02384 Δ119905449
0 Δ1199055960
03069 Δ1199052873
0Δ119905484
01792 Δ1199057022
0 Δ119905749
0 Δ1199051761
0 Δ1199052973
0Δ11990585
0 Δ1199052423
03009 Δ1199054449
0 Δ1199051961
0 Δ1199055673
00081Δ119905165
05385 Δ1199052524
0 Δ1199054549
0 Δ1199052061
0 Δ1199055873
0Δ119905475
05848 Δ1199056925
0 Δ119905450
03518 Δ1199055961
0 Δ1199057174
02501Δ11990596
06558 Δ1199056826
04949 Δ119905650
0 Δ1199051762
0 Δ1199057274
0Δ119905107
0015 Δ1199056527
02957 Δ1199054450
03118 Δ1199051862
00312 Δ1199052375
00048Δ119905117
0 Δ1199053128
0 Δ1199054550
02971 Δ1199052062
00022 Δ1199056275
02319Δ119905127
02883 Δ1199057228
0 Δ1199051651
03311 Δ1199055962
03093 Δ1199056475
0Δ119905137
00488 Δ1199053129
0 Δ1199054751
03843 Δ1199051763
0 Δ1199057376
04701Δ119905437
00184 Δ1199057129
0 Δ1199054851
0 Δ1199051863
00059 Δ1199057476
0Δ119905517
00165 Δ1199053330
0 Δ1199054952
0 Δ1199051963
01605 Δ1199057577
0Δ119905108
00076 Δ1199057430
0 Δ1199051153
0 Δ1199055963
03125 Δ1199057678
0Δ119905118
0 Δ1199053331
0 Δ1199051253
02759 Δ1199056164
0 Δ1199057778
0Δ119905128
02671 Δ1199057331
00514 Δ1199051353
00489 Δ1199056365
0 Δ1199053779
0Δ119905138
00494 Δ1199053432
06332 Δ1199054353
00171 Δ1199053266
00072 Δ1199057879
02437Δ119905438
00161 Δ1199053533
0 Δ1199055053
05228 Δ1199056266
02319 Δ1199053680
0Δ119905508
05093 Δ1199057733
00416 Δ1199055153
00163 Δ1199056466
0 Δ1199057880
03633Δ119905539
0 Δ1199053534
02067 Δ1199051054
0 Δ1199056667
0 Δ1199058581
0Δ1199055210
00881 Δ1199057634
0 Δ1199051254
0 Δ1199056768
0 Δ1199058681
0Δ1199054211
03288 Δ1199053635
0 Δ1199051354
0 Δ1199052769
00239 Δ1199054082
0Δ1199051412
00006 Δ1199053735
02988 Δ1199054354
0 Δ1199052869
0 Δ1199058082
0Δ1199051512
0 Δ1199053937
02264 Δ1199055054
0 Δ1199052969
0 Δ1199058182
0Δ1199052613
0005 Δ1199054037
02523 Δ1199055154
0 Δ1199053069
00006 Δ1199053983
0Δ1199052713
0027 Δ1199058137
0 Δ1199051055
0 Δ1199055669
00331 Δ1199058083
0Δ1199052813
00001 Δ1199053938
03152 Δ1199051155
0 Δ1199055869
00202 Δ1199058183
0Δ1199052913
00001 Δ1199054038
03684 Δ1199051355
0 Δ1199052670
00155 Δ1199058284
0Δ1199053013
0 Δ1199058038
00055 Δ1199054355
0 Δ1199052870
0 Δ1199055485
0Δ1199055813
00262 Δ1199054139
0 Δ1199055055
0 Δ1199052970
0 Δ1199051086
0Δ1199052615
0 Δ1199058440
0 Δ1199055155
0 Δ1199053070
00003 Δ1199051186
00116Δ1199052715
0 Δ1199058341
0 Δ1199051056
00082 Δ1199055670
00368 Δ1199051286
02807Δ1199052815
0 Δ1199053842
01969 Δ1199051156
0 Δ1199055870
00215 Δ1199051386
00363Δ1199052915
0 Δ1199058642
0 Δ1199051256
02863 Δ1199052671
0 Δ1199055086
05105Δ1199053015
0 Δ1199053843
05089 Δ1199054356
00169 Δ1199052771
00031 Δ1199055186
0Δ1199055615
0 Δ1199058543
03278 Δ1199055056
05088 Δ1199052971
00142Δ1199051716
00001 Δ119905244
00333 Δ1199055156
00146 Δ1199053071
0006
shows relay number the second column (119879) shows relayoperating time for a fault close to the circuit breaker ofeach relay and the third column indicates the TMS of therelays From Table 8 all of the values of Δ119905mb are small andpositive numbers The positive values of Δ119905mb show that
there is no miscoordination in the results For example Δ11990541
refers to the relay pairs (4 and 1) that are obtained at 03529seconds The values of the five coefficients of the objectivefunction 120573 120572
1 1205722 119872 and 119873 are obtained as 5855 15 5
125 and 6 respectively When a fault occurs at downstream
ISRN Power Engineering 9
Table 9 Comparison between the proposed method and themethod of [11]
Case 1 Case 2 Case 3 Case 4120573 = 1 120573 = 10 120573 = 10 120573 = 58551205721= 1 120572
1= 10 120572
1= 1 120572
1= 15
1205722= 100 120572
2= 1 120572
2= 10 120572
2= 5
119872 = 2 119872 = 2 119872 = 2 119872 = 125N = 2 N = 2 N = 2 N = 6
sumΔ119905 298211 24115 269 2219sumTMS 1515 1455 156 1132
operating time of the downstreamprotective relays would notbe affected [21] In current grading the pickup current waschosen by considering the maximum possible load currentdue to normal overloading or contingency conditions Theloads of the buses 11 and 26 are the static types and thereis no need to install overcurrent relays on these buses SoTMSs of relays 57 and 79 that are connected to these buses areconsidered to be 005 [22] and other TMSs were calculated
In Table 9 the results of the simulations for the four casesare illustrated In this table the first row shows the fourdifferent cases and the second and the third rows show theresults of the first index (sumΔ119905) and the second index (sumTMS)for these cases The three first cases are related to the methodof [11] where in these cases the coefficients of the objectivefunction are set before optimization processThe values of thecoefficients are shown in the first column of the tableThe lastcase shows the results of the proposed method The values ofΔ119905 in all cases are positive and have not any miscoordination
The advantage of the proposed method is revealed whenthe results of the proposed method (Case 4) are comparedwith the best results of the traditional method of [11]According to Table 9 the best sumTMS and sumΔ119905 of method[11] (between three cases 1 and 2 and 3) are 1455 and24115 respectively whereassumTMS andsumΔt of the proposedmethod are 1132 and 2219 respectively This means thatthe results of Case 4 related to the new proposed methodshow the best coordination So considering the coefficientsof objective function as a part of the optimization prob-lem results are better compared with conventional methodaccording to the results of Tables 4 and 9
7 Conclusion
In this paper a new flexible technique for overcurrent relayscoordination has been proposed In this new technique thecoefficients of the conventional objective functions have beenimproved by optimization problem to obtain the minimumvalues for the TMSs of the relays In the proposed tech-nique GAPSOA optimization method is used to solve theoptimization problem This proposed method is tested on 6-bus case study and 30-bus IEEE case study The results ofthe simulation show the flexibility of the technique and thebest reliability because of the smallest sumTMS and sumΔ119905mbcompared to the conventional coordination methods
Conflict of Interests
The authors declare that there is no conflict of interestsregarding the publication of this paper
References
[1] R Mohammadi H A Abyaneh F Razavi M Al-Dabbaghand S H H Sadeghi ldquoOptimal relays coordination efficientmethod in interconnected power systemsrdquo Journal of ElectricalEngineering vol 61 no 2 pp 75ndash83 2010
[2] K Mazlumi and H A Abyaneh ldquoRelay coordination and pro-tection failure effects on reliability indices in an interconnectedsub-transmission systemrdquo Electric Power Systems Research vol79 no 7 pp 1011ndash1017 2009
[3] D Birla R P Maheshwari and H O Gupta ldquoTime overcurrentrelay coordination a reviewrdquo International Journal of EmergingElectric Power Systems vol 2 no 2 2005
[4] M Ojaghi Z Sudi and J Faiz ldquoImplementation of full adaptivetechnique to optimal coordination of overcurrent relaysrdquo IEEETransactions on Power Delivery vol 28 no 1 pp 235ndash244 2013
[5] C W So and K K Li ldquoOvercurrent relay coordination byevolutionary programmingrdquo Electric Power Systems Researchvol 53 no 2 pp 83ndash90 2000
[6] CW So K K Li K T Lai and K Y Fung ldquoApplication of gen-etic algorithm for overcurrent relay coordinationrdquo in Proceed-ings of the 6th International Conference on Developments inPower System Protection pp 66ndash69 1997
[7] C W So and K K Li ldquoTime coordination method for powersystem protection by evolutionary algorithmrdquo IEEE Transac-tions on Industry Applications vol 36 no 5 pp 1235ndash12402000
[8] J A Sueiro E Diaz-Dorado E Miguez and J Cidras ldquoCoordi-nation of directional overcurrent relay using evolutionary algo-rithm and linear programmingrdquo International Journal of Elec-trical Power amp Energy Systems vol 42 no 1 pp 299ndash305 2012
[9] M Ezzeddine and R Kaczmarek ldquoA novel method for optimalcoordination of directional overcurrent relays considering theiravailable discrete settings and several operation characteristicsrdquoElectric Power Systems Research vol 81 no 7 pp 1475ndash14812011
[10] P P Bedekar and S R Bhide ldquoOptimum coordination ofovercurrent relay timing using continuous genetic algorithmrdquoExpert Systems with Applications vol 38 no 9 pp 11286ndash112922011
[11] F Razavi H A Abyaneh M Al-Dabbagh R Mohammadiand H Torkaman ldquoA new comprehensive genetic algorithmmethod for optimal overcurrent relays coordinationrdquo ElectricPower Systems Research vol 78 no 4 pp 713ndash720 2008
[12] D E Goldberg Genetic Algorithms in Search Optimization andMachine Learning Addison-Wesley Reading Mass USA 1989
[13] D Adler ldquoGenetic algorithms and simulated annealing a mar-rage proposalrdquo in Proceedings of the IEEE International Confer-ence on Neural Networks vol 2 pp 1104ndash1109 1993
[14] K Premalatha and A M Natarajan ldquoHybrid PSO and GA forglobalmaximizationrdquo International Journal of Open Problems inComputer Science and Mathematics vol 2 no 4 2009
[15] H-J Lee G Son and J-W Park ldquoStudy on wind-turbine gen-erator system sizing considering voltage regulation and over-current relay coordinationrdquo IEEE Transactions on Power Sys-tems vol 26 no 3 pp 1283ndash1293 2011
10 ISRN Power Engineering
[16] T Amraee ldquoCoordination of directional overcurrent relaysusing seeker algorithmrdquo IEEE Transactions on Power Deliveryvol 27 no 3 pp 1415ndash1422 2012
[17] P P Bedekar and S R Bhide ldquoOptimum coordination of direc-tional overcurrent relays using the hybrid GA-NLP approachrdquoIEEE Transactions on Power Delivery vol 26 no 1 pp 109ndash1192011
[18] R M Chabanloo H A Abyaneh S S H Kamangar and FRazavi ldquoOptimal combined overcurrent and distance relayscoordination incorporating intelligent overcurrent relays char-acteristic selectionrdquo IEEE Transactions on Power Delivery vol26 no 3 pp 1381ndash1391 2011
[19] H Sharifian H A Abyaneh S K Salman R Mohammadiand F Razavi ldquoDetermination of the minimum break point setusing expert system and genetic algorithmrdquo IEEE Transactionson Power Delivery vol 25 no 3 pp 1284ndash1295 2010
[20] Power system test cases 1999 httpwwweewashingtoneduresearchpstcapf30ieee30cdftxt
[21] P G Slade J-L Wu E J Stacey et al ldquoThe utility requirementsfor a distribution fault current limiterrdquo IEEE Transactions onPower Delivery vol 7 no 2 pp 507ndash515 1992
[22] J R S S Kumara A Atputharajah J B Ekanayake and FJ Mumford ldquoOver current protection coordination of distri-bution networks with fault current limitersrdquo in Proceedings ofthe IEEE Power Engineering Society General Meeting (PES rsquo06)Montreal Canada 2006
International Journal of
AerospaceEngineeringHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
RoboticsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Active and Passive Electronic Components
Control Scienceand Engineering
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
International Journal of
RotatingMachinery
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporation httpwwwhindawicom
Journal ofEngineeringVolume 2014
Submit your manuscripts athttpwwwhindawicom
VLSI Design
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Shock and Vibration
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Civil EngineeringAdvances in
Acoustics and VibrationAdvances in
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Electrical and Computer Engineering
Journal of
Advances inOptoElectronics
Hindawi Publishing Corporation httpwwwhindawicom
Volume 2014
The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
SensorsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Modelling amp Simulation in EngineeringHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Chemical EngineeringInternational Journal of Antennas and
Propagation
International Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Navigation and Observation
International Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
DistributedSensor Networks
International Journal of
2 ISRN Power Engineering
parts of the network Obviously in this case the number ofinterrupted customers increases and consequently the powerquality declines
In [10] continuous genetic algorithm has been usedin a ring fed distribution system for optimal coordinationof overcurrent relays In [11] an objective function hasbeen proposed in which the problem of miscoordinationhas almost been solved The objective function of [11] canprevent the appearance of inappropriate results which makemiscoordination Suitable parameter initializing has beenconsidered in the objective function of the paper that weightsboth the time and the delay time of the backup relays Themain shortcoming of the objective function of [11] is thatsomeof the coefficients of objective function are set by try anderror It is proved by experience that using such coefficientscannot guarantee accessing to the smallest operation time ofthe relays In some cases using inappropriate parameters inobjective function may result in some miscoordination
In this paper a new method for directional overcurrentrelay coordination is proposed in which not only the misco-ordination is omitted but also operation times of the relaysare the smallest This is because in this novel algorithmthe coefficients of the previous proposed objective functionare considered a part of the optimization problem So thecoefficients of the objective function are not constant andthey are not set by try and error In the proposed methodthe coefficients are calculated based on the optimizationtechnique The optimization problem of this paper is solvedusing a hybrid genetic and particle swarm optimizationalgorithmThismethod is applied to 6-bus and 30-bus samplenetworks The results of this method are compared with theresults of the existing ones The simulation results and thecomparisons demonstrate the effectiveness and the advantageof the proposed algorithm
2 Hybrid GA and PSO (HGAPSO) inRelay Coordination Application
By incorporating the GA into the PSO the novel HGAPSOalgorithm is obtained [12]TheHGAPSOA can provide betterresults [13] In this algorithm the initial population of GAis assigned by the solution of PSO The total numbers of theiterations are equivalently shared by GA and PSO First halfof the iterations are carried out by PSO and the solutionsare given as initial population of GA [14] In this section webriefly discuss the application of HGAPSOA in overcurrentrelay coordination According to Figure 1 at first the userinitializes the information such as algorithm parameters(population size iteration numbers mutation and crossoverrange) relay data and network data The HGAPSOA basicsin coordination of the DOCRs are described in 4 steps
Step 1 Initial Generation A number of random particles areproduced The variables of HGAPSOA are the TMSs of theDOCRs and the coefficients of the objective function Inour problem the number of the variables is equal to thenumber of the relays and the number of the objective functioncoefficients The TMSs are randomly generated between 005and 1
Step 2 Evaluate the Objective Function In this step the valueof the objective function is calculated for every gene anddiscerns between good and bad chromosomes
Step 3 PSO Operators In PSO box update the local bestposition experienced by every particle denoted as 119901best andupdate the best position experienced by whole particlesdenoted as 119892best
Step 4 GA Operators The best particles are selected as theinitial population of GA In this step the objective functionevaluation is compared with its initial best chromosome(minimum value in the TMS vector) If the evaluated valueis less than the initial best chromosome set the best chromo-some equal to the evaluated value Then update the positionof the genes by using crossover and mutation operators
Finally if any of the following stopping criteria (inthis study maximum number of iterations) then go to thefollowingmoduleThismodule is used to transfer the optimalrelay TMSs calculated fromHGAPSOA through the interfacesystem to each relay
3 Problem Statement
Toprevent overcurrent relaysmiscoordination and to find theoptimum results of the objective function of [11] the novelobjective function is formulated as follows
119874 sdot 119865 = 1205721timessum(119905
119894)119872
+ 1205722
timessum(Δ119905mb minus 120573 times (Δ119905mb minus1003816100381610038161003816Δ119905mb1003816100381610038161003816))119873
(1)
where 1205721 1205722 and 120573 are weighting coefficients119872 and 119873 are
even numbers 119905119894is the operating time of 119894th overcurrent relay
when a fault occurs next to the relay Δ119905mb is the discrimina-tion time between the main and backup overcurrent relaysΔ119905mb is obtained by
Δ119905mb = 119905b minus 119905m minus CTI (2)
where 119905b and 119905m are the operating time of the backup andmainrelays when a fault occurs next to the main relay The valueof coordination time interval (CTI) is mainly chosen basedon the practical limitations which consist of the relay over-travel time the breaker operating time and the safety marginfor the relay error [15] Generally the suitable CTI is selectedbetween 02 and 05 second In this study CTI is considered tobe 03 seconds According to the proposed objective functionof [11] the weighting coefficients (120573 120572
1 1205722) are set by try and
error and also the coefficients of (119872119873) are constant andcannot guarantee accessing to the smallest operation time ofthe relays
The first term of (1) is the sum of overcurrent relaysrsquooperating time and the second term is the coordinationconstraint To describe the role of the second term of theabove object function consider that Δ119905mb must be positivethen the relative expression (Δ119905mbminus120573sdot(Δ119905mbminus|Δ119905mb|) is equalto Δ119905mb Exactly the mentioned equation if Δ119905mb is negativeis as follows
(1 + 2120573) (Δ119905mb) (3)
ISRN Power Engineering 3
Start
Algorithm parameters inputpopulation size iteration numbermutation and crossover range
Relay and network data
Initial generation
Evaluate objectivefunction
End iteration
Record outputs relay
operation times relay
Update Pbest Position update
SelectionCrossoverMutation
Update gbest
GA operators
PSO operators
End
No
Yes
TMS 1205721 1205722MN
Figure 1 Flowchart of the proposed method
If the coefficient 120573 is a large number the value of (3)is greater than the Δ119905mb and the object function results ina large value and is not selected for the next iterations inthe optimization algorithm Consequently the output resultscontain no miscoordination
4 New Method
In this paper the five coefficients of (1) that is 120573 1205721 1205722
119872 and 119873 beside TMSs are incorporated as a part ofthe optimization parameters The new objective function isshown in (1)
To understand the importance of these coefficients thefollowing notes are helpful
(i) To assure minimizing the main relay operating timea great value must be assigned to 120572
1and119872
(ii) To assure minimizing the backup relay operationtime a great value must be assigned to 120572
2and119873
(iii) To prevent miscoordination and have faster andmoreaccurate convergence choose a large value for 120573 and119873
According to the above notes it is obvious that determin-ing these five coefficients as well as the TMS of the relayswith an optimization algorithm will result in a better relaycoordination Therefore the method presented in this paperoptimizes the objective function coefficients as well as theTMSs of the relays to have a tradeoff between the fast oper-ating time and preventing miscoordination The algorithmapplied to the relays coordination optimization problemfor the proposed technique is provided in Figure 1 In thefirst step of the algorithm the initial values are randomlyguessed The initial values consist of both relayrsquos TMS andthe coefficients of the objective function The relay settingsare packed into a packet each packet is a probable result forthe optimization problem and therefore each member of apacket represents a TMS of a relay In addition there are fiveextra coefficients that should be optimized which belong tothe objective function (120572
1 1205722 120573 119872 and 119873) In the second
step the packet is evaluated by the objective function of (1)The objective function determines the value of each packetby receiving the TMS of all relays After evaluation processthe best packet is chosen from the least objective functionoutput point of view In the next step finishing criteria ofalgorithm are checked to be the limited iterations and yield a
4 ISRN Power Engineering
prespecified fitness value If one of them is satisfied then thealgorithm terminates and goes to the next stage otherwise itreturns to the second step and starts the next iteration
5 Mathematical Overcurrent Relay Models
There are many mathematical models for the overcurrentrelays In this study the mathematical model of overcurrentrelays is considered to be the standard inverse type In thismathematical model the operating time of the overcurrentrelay is expressed as follows [16]
119905 =119896 times TMS(119894sc1198940)
119899
minus 1+ 119871 (4)
where 1198680is relay current setting 119868sc is short-circuit current
119879 is the relay operating time and TMS is the time multipliersetting of the relay TMS varies from 005 to 1 From the IECcurves for standard inverse type relays the parameters of (4)are assumed to be 119871 = 0 119896 = 014 and 119899 = 002
6 Comparison of the Results and Discussion
As described in Section 4 the values of the five coefficientsare variable so the output value of the objective function willnot be an appropriate criterion for comparing results of theproposed algorithm in [11] Therefore in order to gain thisaim two indicators are defined as follows
(i) Summation of TMSs If in a set of results of relay coor-dination there is not any miscoordination betweeneach two relays it can be said that the better coordina-tion has smaller summation of TMSs and therewithrelays have lower operating times
(ii) Summation of Difference between Each Time Opera-tion (sumΔ119905mb) For comparing two sets of the coor-dination results for example result 119860 and result 119861which do not have any miscoordination if value of(5) is true then the set of result 119860 is better than 119861Consider
119899
sum
(mb)=1(Δ119905(mb)119860 minus Δ119905(mb)119861) lt 0 (5)
In (5) the number of pairs of mainbackup (m b) relaysis equal to 119899 In this paper the proposed method is applied totwo different networks namely case study 1 and case study 2(case study 1 consists of 6 buses and case study 2 is the IEEE30-bus system) which are selected
61 Case Study 1 Network and Protection Information Casestudy 1 is 6-bus network shown in Figure 2 This networkconsists of 7 lines 6 buses 2 generators 2 transformers and14 overcurrent relays [17]
All the information about this network including short-circuit current of backup and main relays and relevant infor-mation relative to mainbackup relays have been provided in[11] and also are shown in Table 1
Table 1 Mainbackup pair information
Main relay Backup relay Primary relaySC current
Backup relaycurrent
8 9 4961 4108 7 4961 15202 7 5362 15282 1 5362 8043 2 3334 33344 3 2234 22345 4 1352 13526 5 4965 4116 14 4965 152214 1 4232 79414 9 4232 4071 6 2682 26829 10 1443 144310 11 2334 233411 12 3480 348012 14 5365 152912 13 5365 80513 8 2490 24907 5 4232 4077 13 4232 794
Table 2 119868119897max information
Relay number Maximum loadcurrent Relay number Maximum load
current1 416 8 4582 666 9 4503 500 10 4584 666 11 5415 458 12 4586 458 13 5007 541 14 666
Table 3 The input parameters of the optimization algorithm
Mutate range 03Crossover range 07Number of variables 19Number of population 100Maximum iteration 200Maximum subiteration GA 10Maximum subiteration PSO 10
Table 2 shows the maximum load current passingthrough the relays The way of the relay current settings isdescribed as follows [11]
1198680= 12 times 119868
119897max (6)
ISRN Power Engineering 5
R1
R2
R3R4
R5R6R7
R8R9
R10
R11R12R13
R14
sim
sim
Figure 2 Case study 1 network
32
21 61
63
22
18
46
3
12
44
4
49
95250
5
753483
64
62
23
84
82
41
20
1659
79
5442
85 8657
7
19 8
45 6
48
47
24 6725
68
69
65
70 26
56
12733376
7774
31
30
143855
58
15
39
81
4035
36
37
78
72
13
80
71
66
29
Figure 3 IEEE 30-bus system
6 ISRN Power Engineering
Table 4 The coordination results
Coordination output Reference [11] GAPSOTMS1
015 0066TMS2
035 01833TMS3
025 0146TMS4
01 0069TMS5
01 008TMS6
025 013TMS7
02 012TMS8
025 012TMS9
005 0095TMS10
015 0135TMS11
025 0174TMS12
04 0273TMS13
01 005TMS14
015 011199051
05894 0271199052
12173 0661199053
09621 0581199054
06636 0461199055
07660 0611199056
07623 041199057
07059 0431199058
07625 0371199059
03479 06611990510
06883 06411990511
09835 07111990512
11847 08211990513
04665 02411990514
05944 043Δ11990589
0 0Δ11990587
04673 0296Δ11990527
00028 0Δ11990521
06290 0Δ11990532
02657 0Δ11990543
02057 0Δ11990554
01885 0Δ11990565
0 0Δ119905614
04825 0418Δ119905141
13181 0258Δ119905149
0 0Δ11990516
00532 0Δ119905910
03173 0Δ1199051011
02195 0Δ1199051112
00492 0Δ1199051214
00489 0Δ1199051213
08135 0065Δ119905138
02292 0Δ11990575
0 0Δ119905713
14086 0511sumΔ119905 6699 155sumTMS 275 1741
Table 5 The object function parameters
1205721 251205722 01120573 15722119872 100119873 2
Table 6 Algorithm parameters information
Mutate range 03Crossover range 08Number of variables 91Number of population 200Maximum iteration 500Maximum subiteration GA 10Maximum subiteration PSO 10
All control parameters of algorithm are listed in Table 3The number of the variables in optimization problem is 19Fourteen of the variables are related to the TMS of the relaysand the remaining five variables are the coefficients of theobjective function that is 120573 120572
1 1205722119872119873
The results of the proposedmethod by GAPSO algorithmand the best results of [11] are compared in Table 4 The bestresults of [11] are shown in the second column of Table 4Thethird column of Table 4 represents feasible results for coordi-nation of the relays using the proposed method From Table4 all Δ119905mb values are small and positive and the largest Δ119905mbis 0511 secThe results mean there is not anymiscoordinationin the results Table 4 shows two superiority indicatorsthat is sumTMS and sumΔ119905mb optimized using the proposedalgorithm The first superiority indicator (sum119879119872119878) for theresults of [11] is 275 and for the proposed method is 1741and the second superiority indicator (sumΔ119905mb) for the resultsof [11] is 6699 sec and for the proposed method is 155 secThe superiority indicators show that the results would bemore optimized when the coefficients are optimized by theproposed algorithmThe advantage of thismethod is revealedwhen this new method is compared with the result of [11] inwhich the parameters are set manually in Table 4
With attend to Table 4 more relays operating time thatare earn from proposed method are smaller than [11] Forexample 119905
2in the proposedmethod is 066 seconds and in [11]
is 12173 seconds or 11990512
in proposed method is 082 secondsand in [11] is 11847 sec Also the values of the five parametersof objective function are shown in Table 5
62 Case Study 2 Network and Protection Information Forthe other test case 30-bus IEEE network is considered Thisnetwork has 86 OC relays It consists of 30 buses (132- and33-kV buses) 37 lines 6 generators 4 transformers and86OC relays [18] The distribution section of network thatwill be studied here is shown in Figure 3 [19] The generatortransmission lines and transformer information are givenfrom [20]
ISRN Power Engineering 7
Table 7 Coordination output results
Relay number 119879 TMS1 03092 01172 03092 01173 03467 01194 02095 00685 07561 01026 05671 02277 0248 00918 07271 01899 05679 010710 06679 024511 067 024112 0423 016013 0621 019514 09412 02515 09268 017016 02343 007417 05493 013918 05749 019019 03947 010520 05669 016321 02716 005922 05094 009023 05468 013924 07716 014225 07482 021726 06391 023927 06033 020328 06351 018429 06351 018430 06358 018331 04274 008832 05374 011833 0252 009034 02694 008935 03322 008436 08262 017437 04902 010638 01732 00539 01731 006140 01627 006841 06102 012342 02748 011543 0656 02544 02103 007645 02249 008446 0397 008147 01756 005648 05501 0179
Table 7 Continued
Relay number 119879 TMS49 07792 015550 01803 006151 0654 021152 06578 016653 06173 012954 05556 009355 10366 022456 05839 014358 06095 017659 02618 006560 04635 012961 02769 005662 03095 006163 03954 006664 05534 012865 03576 009466 05278 009967 05855 009968 07435 016169 05109 009570 06543 011371 02269 007872 0477 014373 02072 007074 06521 020475 03362 010476 05226 011577 02853 007378 04494 011680 04341 013781 03934 011182 08588 015483 09303 020284 05091 007785 03488 014486 03566 0079
In this paper four different cases are simulated for asuitable comparison Three cases are simulated according tothemethod of [11] in which the objective function coefficientsare set manually and the last case is simulated according tothe method proposed in this paper in which the objectivefunction coefficients are not set before simulation and theoptimization results show the values of the coefficients Allcases are evaluated by HGAPSO algorithm and all controlparameters of algorithm are listed in Table 6 The parametersare considered the same as 4 test cases A number of variablesin new method are considered 91 86 variables for relaysnumber and 5 variables for (120573 120572
1 1205722119872119873) and for method
proposed in [11] are considered 86Firstly the results of the proposed method by GAPSOA
are shown in Tables 7 and 8 The first column of Table 7
8 ISRN Power Engineering
Table 8 Time difference for each pair of MB relays
Δ11990541
03529 Δ1199051816
00021 Δ119905344
0 Δ1199051557
0 Δ1199055671
00122Δ11990561
0 Δ1199051916
01591 Δ119905145
00337 Δ1199055557
0 Δ1199055871
00025Δ11990571
03146 Δ1199052016
0 Δ119905345
0 Δ1199051458
01002 Δ1199052672
0Δ119905451
03418 Δ1199052118
10402 Δ119905146
0 Δ1199055558
0 Δ1199052772
0Δ11990542
03529 Δ1199052319
0 Δ119905246
0 Δ119905859
0 Δ1199052872
0Δ11990562
0 Δ1199053219
00027 Δ119905647
0 Δ1199054759
05927 Δ1199053072
0Δ11990572
03146 Δ1199056419
0 Δ119905747
03238 Δ1199054859
01788 Δ1199055672
0Δ119905442
03565 Δ1199052220
05459 Δ1199054447
03147 Δ1199051860
0 Δ1199055872
0Δ11990553
0 Δ1199052321
00023 Δ1199054547
03 Δ1199051960
01665 Δ1199052673
00003Δ11990584
0 Δ1199053221
0 Δ1199054648
0 Δ1199052060
00008 Δ1199052773
0Δ119905164
056 Δ1199056221
02384 Δ119905449
0 Δ1199055960
03069 Δ1199052873
0Δ119905484
01792 Δ1199057022
0 Δ119905749
0 Δ1199051761
0 Δ1199052973
0Δ11990585
0 Δ1199052423
03009 Δ1199054449
0 Δ1199051961
0 Δ1199055673
00081Δ119905165
05385 Δ1199052524
0 Δ1199054549
0 Δ1199052061
0 Δ1199055873
0Δ119905475
05848 Δ1199056925
0 Δ119905450
03518 Δ1199055961
0 Δ1199057174
02501Δ11990596
06558 Δ1199056826
04949 Δ119905650
0 Δ1199051762
0 Δ1199057274
0Δ119905107
0015 Δ1199056527
02957 Δ1199054450
03118 Δ1199051862
00312 Δ1199052375
00048Δ119905117
0 Δ1199053128
0 Δ1199054550
02971 Δ1199052062
00022 Δ1199056275
02319Δ119905127
02883 Δ1199057228
0 Δ1199051651
03311 Δ1199055962
03093 Δ1199056475
0Δ119905137
00488 Δ1199053129
0 Δ1199054751
03843 Δ1199051763
0 Δ1199057376
04701Δ119905437
00184 Δ1199057129
0 Δ1199054851
0 Δ1199051863
00059 Δ1199057476
0Δ119905517
00165 Δ1199053330
0 Δ1199054952
0 Δ1199051963
01605 Δ1199057577
0Δ119905108
00076 Δ1199057430
0 Δ1199051153
0 Δ1199055963
03125 Δ1199057678
0Δ119905118
0 Δ1199053331
0 Δ1199051253
02759 Δ1199056164
0 Δ1199057778
0Δ119905128
02671 Δ1199057331
00514 Δ1199051353
00489 Δ1199056365
0 Δ1199053779
0Δ119905138
00494 Δ1199053432
06332 Δ1199054353
00171 Δ1199053266
00072 Δ1199057879
02437Δ119905438
00161 Δ1199053533
0 Δ1199055053
05228 Δ1199056266
02319 Δ1199053680
0Δ119905508
05093 Δ1199057733
00416 Δ1199055153
00163 Δ1199056466
0 Δ1199057880
03633Δ119905539
0 Δ1199053534
02067 Δ1199051054
0 Δ1199056667
0 Δ1199058581
0Δ1199055210
00881 Δ1199057634
0 Δ1199051254
0 Δ1199056768
0 Δ1199058681
0Δ1199054211
03288 Δ1199053635
0 Δ1199051354
0 Δ1199052769
00239 Δ1199054082
0Δ1199051412
00006 Δ1199053735
02988 Δ1199054354
0 Δ1199052869
0 Δ1199058082
0Δ1199051512
0 Δ1199053937
02264 Δ1199055054
0 Δ1199052969
0 Δ1199058182
0Δ1199052613
0005 Δ1199054037
02523 Δ1199055154
0 Δ1199053069
00006 Δ1199053983
0Δ1199052713
0027 Δ1199058137
0 Δ1199051055
0 Δ1199055669
00331 Δ1199058083
0Δ1199052813
00001 Δ1199053938
03152 Δ1199051155
0 Δ1199055869
00202 Δ1199058183
0Δ1199052913
00001 Δ1199054038
03684 Δ1199051355
0 Δ1199052670
00155 Δ1199058284
0Δ1199053013
0 Δ1199058038
00055 Δ1199054355
0 Δ1199052870
0 Δ1199055485
0Δ1199055813
00262 Δ1199054139
0 Δ1199055055
0 Δ1199052970
0 Δ1199051086
0Δ1199052615
0 Δ1199058440
0 Δ1199055155
0 Δ1199053070
00003 Δ1199051186
00116Δ1199052715
0 Δ1199058341
0 Δ1199051056
00082 Δ1199055670
00368 Δ1199051286
02807Δ1199052815
0 Δ1199053842
01969 Δ1199051156
0 Δ1199055870
00215 Δ1199051386
00363Δ1199052915
0 Δ1199058642
0 Δ1199051256
02863 Δ1199052671
0 Δ1199055086
05105Δ1199053015
0 Δ1199053843
05089 Δ1199054356
00169 Δ1199052771
00031 Δ1199055186
0Δ1199055615
0 Δ1199058543
03278 Δ1199055056
05088 Δ1199052971
00142Δ1199051716
00001 Δ119905244
00333 Δ1199055156
00146 Δ1199053071
0006
shows relay number the second column (119879) shows relayoperating time for a fault close to the circuit breaker ofeach relay and the third column indicates the TMS of therelays From Table 8 all of the values of Δ119905mb are small andpositive numbers The positive values of Δ119905mb show that
there is no miscoordination in the results For example Δ11990541
refers to the relay pairs (4 and 1) that are obtained at 03529seconds The values of the five coefficients of the objectivefunction 120573 120572
1 1205722 119872 and 119873 are obtained as 5855 15 5
125 and 6 respectively When a fault occurs at downstream
ISRN Power Engineering 9
Table 9 Comparison between the proposed method and themethod of [11]
Case 1 Case 2 Case 3 Case 4120573 = 1 120573 = 10 120573 = 10 120573 = 58551205721= 1 120572
1= 10 120572
1= 1 120572
1= 15
1205722= 100 120572
2= 1 120572
2= 10 120572
2= 5
119872 = 2 119872 = 2 119872 = 2 119872 = 125N = 2 N = 2 N = 2 N = 6
sumΔ119905 298211 24115 269 2219sumTMS 1515 1455 156 1132
operating time of the downstreamprotective relays would notbe affected [21] In current grading the pickup current waschosen by considering the maximum possible load currentdue to normal overloading or contingency conditions Theloads of the buses 11 and 26 are the static types and thereis no need to install overcurrent relays on these buses SoTMSs of relays 57 and 79 that are connected to these buses areconsidered to be 005 [22] and other TMSs were calculated
In Table 9 the results of the simulations for the four casesare illustrated In this table the first row shows the fourdifferent cases and the second and the third rows show theresults of the first index (sumΔ119905) and the second index (sumTMS)for these cases The three first cases are related to the methodof [11] where in these cases the coefficients of the objectivefunction are set before optimization processThe values of thecoefficients are shown in the first column of the tableThe lastcase shows the results of the proposed method The values ofΔ119905 in all cases are positive and have not any miscoordination
The advantage of the proposed method is revealed whenthe results of the proposed method (Case 4) are comparedwith the best results of the traditional method of [11]According to Table 9 the best sumTMS and sumΔ119905 of method[11] (between three cases 1 and 2 and 3) are 1455 and24115 respectively whereassumTMS andsumΔt of the proposedmethod are 1132 and 2219 respectively This means thatthe results of Case 4 related to the new proposed methodshow the best coordination So considering the coefficientsof objective function as a part of the optimization prob-lem results are better compared with conventional methodaccording to the results of Tables 4 and 9
7 Conclusion
In this paper a new flexible technique for overcurrent relayscoordination has been proposed In this new technique thecoefficients of the conventional objective functions have beenimproved by optimization problem to obtain the minimumvalues for the TMSs of the relays In the proposed tech-nique GAPSOA optimization method is used to solve theoptimization problem This proposed method is tested on 6-bus case study and 30-bus IEEE case study The results ofthe simulation show the flexibility of the technique and thebest reliability because of the smallest sumTMS and sumΔ119905mbcompared to the conventional coordination methods
Conflict of Interests
The authors declare that there is no conflict of interestsregarding the publication of this paper
References
[1] R Mohammadi H A Abyaneh F Razavi M Al-Dabbaghand S H H Sadeghi ldquoOptimal relays coordination efficientmethod in interconnected power systemsrdquo Journal of ElectricalEngineering vol 61 no 2 pp 75ndash83 2010
[2] K Mazlumi and H A Abyaneh ldquoRelay coordination and pro-tection failure effects on reliability indices in an interconnectedsub-transmission systemrdquo Electric Power Systems Research vol79 no 7 pp 1011ndash1017 2009
[3] D Birla R P Maheshwari and H O Gupta ldquoTime overcurrentrelay coordination a reviewrdquo International Journal of EmergingElectric Power Systems vol 2 no 2 2005
[4] M Ojaghi Z Sudi and J Faiz ldquoImplementation of full adaptivetechnique to optimal coordination of overcurrent relaysrdquo IEEETransactions on Power Delivery vol 28 no 1 pp 235ndash244 2013
[5] C W So and K K Li ldquoOvercurrent relay coordination byevolutionary programmingrdquo Electric Power Systems Researchvol 53 no 2 pp 83ndash90 2000
[6] CW So K K Li K T Lai and K Y Fung ldquoApplication of gen-etic algorithm for overcurrent relay coordinationrdquo in Proceed-ings of the 6th International Conference on Developments inPower System Protection pp 66ndash69 1997
[7] C W So and K K Li ldquoTime coordination method for powersystem protection by evolutionary algorithmrdquo IEEE Transac-tions on Industry Applications vol 36 no 5 pp 1235ndash12402000
[8] J A Sueiro E Diaz-Dorado E Miguez and J Cidras ldquoCoordi-nation of directional overcurrent relay using evolutionary algo-rithm and linear programmingrdquo International Journal of Elec-trical Power amp Energy Systems vol 42 no 1 pp 299ndash305 2012
[9] M Ezzeddine and R Kaczmarek ldquoA novel method for optimalcoordination of directional overcurrent relays considering theiravailable discrete settings and several operation characteristicsrdquoElectric Power Systems Research vol 81 no 7 pp 1475ndash14812011
[10] P P Bedekar and S R Bhide ldquoOptimum coordination ofovercurrent relay timing using continuous genetic algorithmrdquoExpert Systems with Applications vol 38 no 9 pp 11286ndash112922011
[11] F Razavi H A Abyaneh M Al-Dabbagh R Mohammadiand H Torkaman ldquoA new comprehensive genetic algorithmmethod for optimal overcurrent relays coordinationrdquo ElectricPower Systems Research vol 78 no 4 pp 713ndash720 2008
[12] D E Goldberg Genetic Algorithms in Search Optimization andMachine Learning Addison-Wesley Reading Mass USA 1989
[13] D Adler ldquoGenetic algorithms and simulated annealing a mar-rage proposalrdquo in Proceedings of the IEEE International Confer-ence on Neural Networks vol 2 pp 1104ndash1109 1993
[14] K Premalatha and A M Natarajan ldquoHybrid PSO and GA forglobalmaximizationrdquo International Journal of Open Problems inComputer Science and Mathematics vol 2 no 4 2009
[15] H-J Lee G Son and J-W Park ldquoStudy on wind-turbine gen-erator system sizing considering voltage regulation and over-current relay coordinationrdquo IEEE Transactions on Power Sys-tems vol 26 no 3 pp 1283ndash1293 2011
10 ISRN Power Engineering
[16] T Amraee ldquoCoordination of directional overcurrent relaysusing seeker algorithmrdquo IEEE Transactions on Power Deliveryvol 27 no 3 pp 1415ndash1422 2012
[17] P P Bedekar and S R Bhide ldquoOptimum coordination of direc-tional overcurrent relays using the hybrid GA-NLP approachrdquoIEEE Transactions on Power Delivery vol 26 no 1 pp 109ndash1192011
[18] R M Chabanloo H A Abyaneh S S H Kamangar and FRazavi ldquoOptimal combined overcurrent and distance relayscoordination incorporating intelligent overcurrent relays char-acteristic selectionrdquo IEEE Transactions on Power Delivery vol26 no 3 pp 1381ndash1391 2011
[19] H Sharifian H A Abyaneh S K Salman R Mohammadiand F Razavi ldquoDetermination of the minimum break point setusing expert system and genetic algorithmrdquo IEEE Transactionson Power Delivery vol 25 no 3 pp 1284ndash1295 2010
[20] Power system test cases 1999 httpwwweewashingtoneduresearchpstcapf30ieee30cdftxt
[21] P G Slade J-L Wu E J Stacey et al ldquoThe utility requirementsfor a distribution fault current limiterrdquo IEEE Transactions onPower Delivery vol 7 no 2 pp 507ndash515 1992
[22] J R S S Kumara A Atputharajah J B Ekanayake and FJ Mumford ldquoOver current protection coordination of distri-bution networks with fault current limitersrdquo in Proceedings ofthe IEEE Power Engineering Society General Meeting (PES rsquo06)Montreal Canada 2006
International Journal of
AerospaceEngineeringHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
RoboticsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Active and Passive Electronic Components
Control Scienceand Engineering
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
International Journal of
RotatingMachinery
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporation httpwwwhindawicom
Journal ofEngineeringVolume 2014
Submit your manuscripts athttpwwwhindawicom
VLSI Design
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Shock and Vibration
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Civil EngineeringAdvances in
Acoustics and VibrationAdvances in
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Electrical and Computer Engineering
Journal of
Advances inOptoElectronics
Hindawi Publishing Corporation httpwwwhindawicom
Volume 2014
The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
SensorsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Modelling amp Simulation in EngineeringHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Chemical EngineeringInternational Journal of Antennas and
Propagation
International Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Navigation and Observation
International Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
DistributedSensor Networks
International Journal of
ISRN Power Engineering 3
Start
Algorithm parameters inputpopulation size iteration numbermutation and crossover range
Relay and network data
Initial generation
Evaluate objectivefunction
End iteration
Record outputs relay
operation times relay
Update Pbest Position update
SelectionCrossoverMutation
Update gbest
GA operators
PSO operators
End
No
Yes
TMS 1205721 1205722MN
Figure 1 Flowchart of the proposed method
If the coefficient 120573 is a large number the value of (3)is greater than the Δ119905mb and the object function results ina large value and is not selected for the next iterations inthe optimization algorithm Consequently the output resultscontain no miscoordination
4 New Method
In this paper the five coefficients of (1) that is 120573 1205721 1205722
119872 and 119873 beside TMSs are incorporated as a part ofthe optimization parameters The new objective function isshown in (1)
To understand the importance of these coefficients thefollowing notes are helpful
(i) To assure minimizing the main relay operating timea great value must be assigned to 120572
1and119872
(ii) To assure minimizing the backup relay operationtime a great value must be assigned to 120572
2and119873
(iii) To prevent miscoordination and have faster andmoreaccurate convergence choose a large value for 120573 and119873
According to the above notes it is obvious that determin-ing these five coefficients as well as the TMS of the relayswith an optimization algorithm will result in a better relaycoordination Therefore the method presented in this paperoptimizes the objective function coefficients as well as theTMSs of the relays to have a tradeoff between the fast oper-ating time and preventing miscoordination The algorithmapplied to the relays coordination optimization problemfor the proposed technique is provided in Figure 1 In thefirst step of the algorithm the initial values are randomlyguessed The initial values consist of both relayrsquos TMS andthe coefficients of the objective function The relay settingsare packed into a packet each packet is a probable result forthe optimization problem and therefore each member of apacket represents a TMS of a relay In addition there are fiveextra coefficients that should be optimized which belong tothe objective function (120572
1 1205722 120573 119872 and 119873) In the second
step the packet is evaluated by the objective function of (1)The objective function determines the value of each packetby receiving the TMS of all relays After evaluation processthe best packet is chosen from the least objective functionoutput point of view In the next step finishing criteria ofalgorithm are checked to be the limited iterations and yield a
4 ISRN Power Engineering
prespecified fitness value If one of them is satisfied then thealgorithm terminates and goes to the next stage otherwise itreturns to the second step and starts the next iteration
5 Mathematical Overcurrent Relay Models
There are many mathematical models for the overcurrentrelays In this study the mathematical model of overcurrentrelays is considered to be the standard inverse type In thismathematical model the operating time of the overcurrentrelay is expressed as follows [16]
119905 =119896 times TMS(119894sc1198940)
119899
minus 1+ 119871 (4)
where 1198680is relay current setting 119868sc is short-circuit current
119879 is the relay operating time and TMS is the time multipliersetting of the relay TMS varies from 005 to 1 From the IECcurves for standard inverse type relays the parameters of (4)are assumed to be 119871 = 0 119896 = 014 and 119899 = 002
6 Comparison of the Results and Discussion
As described in Section 4 the values of the five coefficientsare variable so the output value of the objective function willnot be an appropriate criterion for comparing results of theproposed algorithm in [11] Therefore in order to gain thisaim two indicators are defined as follows
(i) Summation of TMSs If in a set of results of relay coor-dination there is not any miscoordination betweeneach two relays it can be said that the better coordina-tion has smaller summation of TMSs and therewithrelays have lower operating times
(ii) Summation of Difference between Each Time Opera-tion (sumΔ119905mb) For comparing two sets of the coor-dination results for example result 119860 and result 119861which do not have any miscoordination if value of(5) is true then the set of result 119860 is better than 119861Consider
119899
sum
(mb)=1(Δ119905(mb)119860 minus Δ119905(mb)119861) lt 0 (5)
In (5) the number of pairs of mainbackup (m b) relaysis equal to 119899 In this paper the proposed method is applied totwo different networks namely case study 1 and case study 2(case study 1 consists of 6 buses and case study 2 is the IEEE30-bus system) which are selected
61 Case Study 1 Network and Protection Information Casestudy 1 is 6-bus network shown in Figure 2 This networkconsists of 7 lines 6 buses 2 generators 2 transformers and14 overcurrent relays [17]
All the information about this network including short-circuit current of backup and main relays and relevant infor-mation relative to mainbackup relays have been provided in[11] and also are shown in Table 1
Table 1 Mainbackup pair information
Main relay Backup relay Primary relaySC current
Backup relaycurrent
8 9 4961 4108 7 4961 15202 7 5362 15282 1 5362 8043 2 3334 33344 3 2234 22345 4 1352 13526 5 4965 4116 14 4965 152214 1 4232 79414 9 4232 4071 6 2682 26829 10 1443 144310 11 2334 233411 12 3480 348012 14 5365 152912 13 5365 80513 8 2490 24907 5 4232 4077 13 4232 794
Table 2 119868119897max information
Relay number Maximum loadcurrent Relay number Maximum load
current1 416 8 4582 666 9 4503 500 10 4584 666 11 5415 458 12 4586 458 13 5007 541 14 666
Table 3 The input parameters of the optimization algorithm
Mutate range 03Crossover range 07Number of variables 19Number of population 100Maximum iteration 200Maximum subiteration GA 10Maximum subiteration PSO 10
Table 2 shows the maximum load current passingthrough the relays The way of the relay current settings isdescribed as follows [11]
1198680= 12 times 119868
119897max (6)
ISRN Power Engineering 5
R1
R2
R3R4
R5R6R7
R8R9
R10
R11R12R13
R14
sim
sim
Figure 2 Case study 1 network
32
21 61
63
22
18
46
3
12
44
4
49
95250
5
753483
64
62
23
84
82
41
20
1659
79
5442
85 8657
7
19 8
45 6
48
47
24 6725
68
69
65
70 26
56
12733376
7774
31
30
143855
58
15
39
81
4035
36
37
78
72
13
80
71
66
29
Figure 3 IEEE 30-bus system
6 ISRN Power Engineering
Table 4 The coordination results
Coordination output Reference [11] GAPSOTMS1
015 0066TMS2
035 01833TMS3
025 0146TMS4
01 0069TMS5
01 008TMS6
025 013TMS7
02 012TMS8
025 012TMS9
005 0095TMS10
015 0135TMS11
025 0174TMS12
04 0273TMS13
01 005TMS14
015 011199051
05894 0271199052
12173 0661199053
09621 0581199054
06636 0461199055
07660 0611199056
07623 041199057
07059 0431199058
07625 0371199059
03479 06611990510
06883 06411990511
09835 07111990512
11847 08211990513
04665 02411990514
05944 043Δ11990589
0 0Δ11990587
04673 0296Δ11990527
00028 0Δ11990521
06290 0Δ11990532
02657 0Δ11990543
02057 0Δ11990554
01885 0Δ11990565
0 0Δ119905614
04825 0418Δ119905141
13181 0258Δ119905149
0 0Δ11990516
00532 0Δ119905910
03173 0Δ1199051011
02195 0Δ1199051112
00492 0Δ1199051214
00489 0Δ1199051213
08135 0065Δ119905138
02292 0Δ11990575
0 0Δ119905713
14086 0511sumΔ119905 6699 155sumTMS 275 1741
Table 5 The object function parameters
1205721 251205722 01120573 15722119872 100119873 2
Table 6 Algorithm parameters information
Mutate range 03Crossover range 08Number of variables 91Number of population 200Maximum iteration 500Maximum subiteration GA 10Maximum subiteration PSO 10
All control parameters of algorithm are listed in Table 3The number of the variables in optimization problem is 19Fourteen of the variables are related to the TMS of the relaysand the remaining five variables are the coefficients of theobjective function that is 120573 120572
1 1205722119872119873
The results of the proposedmethod by GAPSO algorithmand the best results of [11] are compared in Table 4 The bestresults of [11] are shown in the second column of Table 4Thethird column of Table 4 represents feasible results for coordi-nation of the relays using the proposed method From Table4 all Δ119905mb values are small and positive and the largest Δ119905mbis 0511 secThe results mean there is not anymiscoordinationin the results Table 4 shows two superiority indicatorsthat is sumTMS and sumΔ119905mb optimized using the proposedalgorithm The first superiority indicator (sum119879119872119878) for theresults of [11] is 275 and for the proposed method is 1741and the second superiority indicator (sumΔ119905mb) for the resultsof [11] is 6699 sec and for the proposed method is 155 secThe superiority indicators show that the results would bemore optimized when the coefficients are optimized by theproposed algorithmThe advantage of thismethod is revealedwhen this new method is compared with the result of [11] inwhich the parameters are set manually in Table 4
With attend to Table 4 more relays operating time thatare earn from proposed method are smaller than [11] Forexample 119905
2in the proposedmethod is 066 seconds and in [11]
is 12173 seconds or 11990512
in proposed method is 082 secondsand in [11] is 11847 sec Also the values of the five parametersof objective function are shown in Table 5
62 Case Study 2 Network and Protection Information Forthe other test case 30-bus IEEE network is considered Thisnetwork has 86 OC relays It consists of 30 buses (132- and33-kV buses) 37 lines 6 generators 4 transformers and86OC relays [18] The distribution section of network thatwill be studied here is shown in Figure 3 [19] The generatortransmission lines and transformer information are givenfrom [20]
ISRN Power Engineering 7
Table 7 Coordination output results
Relay number 119879 TMS1 03092 01172 03092 01173 03467 01194 02095 00685 07561 01026 05671 02277 0248 00918 07271 01899 05679 010710 06679 024511 067 024112 0423 016013 0621 019514 09412 02515 09268 017016 02343 007417 05493 013918 05749 019019 03947 010520 05669 016321 02716 005922 05094 009023 05468 013924 07716 014225 07482 021726 06391 023927 06033 020328 06351 018429 06351 018430 06358 018331 04274 008832 05374 011833 0252 009034 02694 008935 03322 008436 08262 017437 04902 010638 01732 00539 01731 006140 01627 006841 06102 012342 02748 011543 0656 02544 02103 007645 02249 008446 0397 008147 01756 005648 05501 0179
Table 7 Continued
Relay number 119879 TMS49 07792 015550 01803 006151 0654 021152 06578 016653 06173 012954 05556 009355 10366 022456 05839 014358 06095 017659 02618 006560 04635 012961 02769 005662 03095 006163 03954 006664 05534 012865 03576 009466 05278 009967 05855 009968 07435 016169 05109 009570 06543 011371 02269 007872 0477 014373 02072 007074 06521 020475 03362 010476 05226 011577 02853 007378 04494 011680 04341 013781 03934 011182 08588 015483 09303 020284 05091 007785 03488 014486 03566 0079
In this paper four different cases are simulated for asuitable comparison Three cases are simulated according tothemethod of [11] in which the objective function coefficientsare set manually and the last case is simulated according tothe method proposed in this paper in which the objectivefunction coefficients are not set before simulation and theoptimization results show the values of the coefficients Allcases are evaluated by HGAPSO algorithm and all controlparameters of algorithm are listed in Table 6 The parametersare considered the same as 4 test cases A number of variablesin new method are considered 91 86 variables for relaysnumber and 5 variables for (120573 120572
1 1205722119872119873) and for method
proposed in [11] are considered 86Firstly the results of the proposed method by GAPSOA
are shown in Tables 7 and 8 The first column of Table 7
8 ISRN Power Engineering
Table 8 Time difference for each pair of MB relays
Δ11990541
03529 Δ1199051816
00021 Δ119905344
0 Δ1199051557
0 Δ1199055671
00122Δ11990561
0 Δ1199051916
01591 Δ119905145
00337 Δ1199055557
0 Δ1199055871
00025Δ11990571
03146 Δ1199052016
0 Δ119905345
0 Δ1199051458
01002 Δ1199052672
0Δ119905451
03418 Δ1199052118
10402 Δ119905146
0 Δ1199055558
0 Δ1199052772
0Δ11990542
03529 Δ1199052319
0 Δ119905246
0 Δ119905859
0 Δ1199052872
0Δ11990562
0 Δ1199053219
00027 Δ119905647
0 Δ1199054759
05927 Δ1199053072
0Δ11990572
03146 Δ1199056419
0 Δ119905747
03238 Δ1199054859
01788 Δ1199055672
0Δ119905442
03565 Δ1199052220
05459 Δ1199054447
03147 Δ1199051860
0 Δ1199055872
0Δ11990553
0 Δ1199052321
00023 Δ1199054547
03 Δ1199051960
01665 Δ1199052673
00003Δ11990584
0 Δ1199053221
0 Δ1199054648
0 Δ1199052060
00008 Δ1199052773
0Δ119905164
056 Δ1199056221
02384 Δ119905449
0 Δ1199055960
03069 Δ1199052873
0Δ119905484
01792 Δ1199057022
0 Δ119905749
0 Δ1199051761
0 Δ1199052973
0Δ11990585
0 Δ1199052423
03009 Δ1199054449
0 Δ1199051961
0 Δ1199055673
00081Δ119905165
05385 Δ1199052524
0 Δ1199054549
0 Δ1199052061
0 Δ1199055873
0Δ119905475
05848 Δ1199056925
0 Δ119905450
03518 Δ1199055961
0 Δ1199057174
02501Δ11990596
06558 Δ1199056826
04949 Δ119905650
0 Δ1199051762
0 Δ1199057274
0Δ119905107
0015 Δ1199056527
02957 Δ1199054450
03118 Δ1199051862
00312 Δ1199052375
00048Δ119905117
0 Δ1199053128
0 Δ1199054550
02971 Δ1199052062
00022 Δ1199056275
02319Δ119905127
02883 Δ1199057228
0 Δ1199051651
03311 Δ1199055962
03093 Δ1199056475
0Δ119905137
00488 Δ1199053129
0 Δ1199054751
03843 Δ1199051763
0 Δ1199057376
04701Δ119905437
00184 Δ1199057129
0 Δ1199054851
0 Δ1199051863
00059 Δ1199057476
0Δ119905517
00165 Δ1199053330
0 Δ1199054952
0 Δ1199051963
01605 Δ1199057577
0Δ119905108
00076 Δ1199057430
0 Δ1199051153
0 Δ1199055963
03125 Δ1199057678
0Δ119905118
0 Δ1199053331
0 Δ1199051253
02759 Δ1199056164
0 Δ1199057778
0Δ119905128
02671 Δ1199057331
00514 Δ1199051353
00489 Δ1199056365
0 Δ1199053779
0Δ119905138
00494 Δ1199053432
06332 Δ1199054353
00171 Δ1199053266
00072 Δ1199057879
02437Δ119905438
00161 Δ1199053533
0 Δ1199055053
05228 Δ1199056266
02319 Δ1199053680
0Δ119905508
05093 Δ1199057733
00416 Δ1199055153
00163 Δ1199056466
0 Δ1199057880
03633Δ119905539
0 Δ1199053534
02067 Δ1199051054
0 Δ1199056667
0 Δ1199058581
0Δ1199055210
00881 Δ1199057634
0 Δ1199051254
0 Δ1199056768
0 Δ1199058681
0Δ1199054211
03288 Δ1199053635
0 Δ1199051354
0 Δ1199052769
00239 Δ1199054082
0Δ1199051412
00006 Δ1199053735
02988 Δ1199054354
0 Δ1199052869
0 Δ1199058082
0Δ1199051512
0 Δ1199053937
02264 Δ1199055054
0 Δ1199052969
0 Δ1199058182
0Δ1199052613
0005 Δ1199054037
02523 Δ1199055154
0 Δ1199053069
00006 Δ1199053983
0Δ1199052713
0027 Δ1199058137
0 Δ1199051055
0 Δ1199055669
00331 Δ1199058083
0Δ1199052813
00001 Δ1199053938
03152 Δ1199051155
0 Δ1199055869
00202 Δ1199058183
0Δ1199052913
00001 Δ1199054038
03684 Δ1199051355
0 Δ1199052670
00155 Δ1199058284
0Δ1199053013
0 Δ1199058038
00055 Δ1199054355
0 Δ1199052870
0 Δ1199055485
0Δ1199055813
00262 Δ1199054139
0 Δ1199055055
0 Δ1199052970
0 Δ1199051086
0Δ1199052615
0 Δ1199058440
0 Δ1199055155
0 Δ1199053070
00003 Δ1199051186
00116Δ1199052715
0 Δ1199058341
0 Δ1199051056
00082 Δ1199055670
00368 Δ1199051286
02807Δ1199052815
0 Δ1199053842
01969 Δ1199051156
0 Δ1199055870
00215 Δ1199051386
00363Δ1199052915
0 Δ1199058642
0 Δ1199051256
02863 Δ1199052671
0 Δ1199055086
05105Δ1199053015
0 Δ1199053843
05089 Δ1199054356
00169 Δ1199052771
00031 Δ1199055186
0Δ1199055615
0 Δ1199058543
03278 Δ1199055056
05088 Δ1199052971
00142Δ1199051716
00001 Δ119905244
00333 Δ1199055156
00146 Δ1199053071
0006
shows relay number the second column (119879) shows relayoperating time for a fault close to the circuit breaker ofeach relay and the third column indicates the TMS of therelays From Table 8 all of the values of Δ119905mb are small andpositive numbers The positive values of Δ119905mb show that
there is no miscoordination in the results For example Δ11990541
refers to the relay pairs (4 and 1) that are obtained at 03529seconds The values of the five coefficients of the objectivefunction 120573 120572
1 1205722 119872 and 119873 are obtained as 5855 15 5
125 and 6 respectively When a fault occurs at downstream
ISRN Power Engineering 9
Table 9 Comparison between the proposed method and themethod of [11]
Case 1 Case 2 Case 3 Case 4120573 = 1 120573 = 10 120573 = 10 120573 = 58551205721= 1 120572
1= 10 120572
1= 1 120572
1= 15
1205722= 100 120572
2= 1 120572
2= 10 120572
2= 5
119872 = 2 119872 = 2 119872 = 2 119872 = 125N = 2 N = 2 N = 2 N = 6
sumΔ119905 298211 24115 269 2219sumTMS 1515 1455 156 1132
operating time of the downstreamprotective relays would notbe affected [21] In current grading the pickup current waschosen by considering the maximum possible load currentdue to normal overloading or contingency conditions Theloads of the buses 11 and 26 are the static types and thereis no need to install overcurrent relays on these buses SoTMSs of relays 57 and 79 that are connected to these buses areconsidered to be 005 [22] and other TMSs were calculated
In Table 9 the results of the simulations for the four casesare illustrated In this table the first row shows the fourdifferent cases and the second and the third rows show theresults of the first index (sumΔ119905) and the second index (sumTMS)for these cases The three first cases are related to the methodof [11] where in these cases the coefficients of the objectivefunction are set before optimization processThe values of thecoefficients are shown in the first column of the tableThe lastcase shows the results of the proposed method The values ofΔ119905 in all cases are positive and have not any miscoordination
The advantage of the proposed method is revealed whenthe results of the proposed method (Case 4) are comparedwith the best results of the traditional method of [11]According to Table 9 the best sumTMS and sumΔ119905 of method[11] (between three cases 1 and 2 and 3) are 1455 and24115 respectively whereassumTMS andsumΔt of the proposedmethod are 1132 and 2219 respectively This means thatthe results of Case 4 related to the new proposed methodshow the best coordination So considering the coefficientsof objective function as a part of the optimization prob-lem results are better compared with conventional methodaccording to the results of Tables 4 and 9
7 Conclusion
In this paper a new flexible technique for overcurrent relayscoordination has been proposed In this new technique thecoefficients of the conventional objective functions have beenimproved by optimization problem to obtain the minimumvalues for the TMSs of the relays In the proposed tech-nique GAPSOA optimization method is used to solve theoptimization problem This proposed method is tested on 6-bus case study and 30-bus IEEE case study The results ofthe simulation show the flexibility of the technique and thebest reliability because of the smallest sumTMS and sumΔ119905mbcompared to the conventional coordination methods
Conflict of Interests
The authors declare that there is no conflict of interestsregarding the publication of this paper
References
[1] R Mohammadi H A Abyaneh F Razavi M Al-Dabbaghand S H H Sadeghi ldquoOptimal relays coordination efficientmethod in interconnected power systemsrdquo Journal of ElectricalEngineering vol 61 no 2 pp 75ndash83 2010
[2] K Mazlumi and H A Abyaneh ldquoRelay coordination and pro-tection failure effects on reliability indices in an interconnectedsub-transmission systemrdquo Electric Power Systems Research vol79 no 7 pp 1011ndash1017 2009
[3] D Birla R P Maheshwari and H O Gupta ldquoTime overcurrentrelay coordination a reviewrdquo International Journal of EmergingElectric Power Systems vol 2 no 2 2005
[4] M Ojaghi Z Sudi and J Faiz ldquoImplementation of full adaptivetechnique to optimal coordination of overcurrent relaysrdquo IEEETransactions on Power Delivery vol 28 no 1 pp 235ndash244 2013
[5] C W So and K K Li ldquoOvercurrent relay coordination byevolutionary programmingrdquo Electric Power Systems Researchvol 53 no 2 pp 83ndash90 2000
[6] CW So K K Li K T Lai and K Y Fung ldquoApplication of gen-etic algorithm for overcurrent relay coordinationrdquo in Proceed-ings of the 6th International Conference on Developments inPower System Protection pp 66ndash69 1997
[7] C W So and K K Li ldquoTime coordination method for powersystem protection by evolutionary algorithmrdquo IEEE Transac-tions on Industry Applications vol 36 no 5 pp 1235ndash12402000
[8] J A Sueiro E Diaz-Dorado E Miguez and J Cidras ldquoCoordi-nation of directional overcurrent relay using evolutionary algo-rithm and linear programmingrdquo International Journal of Elec-trical Power amp Energy Systems vol 42 no 1 pp 299ndash305 2012
[9] M Ezzeddine and R Kaczmarek ldquoA novel method for optimalcoordination of directional overcurrent relays considering theiravailable discrete settings and several operation characteristicsrdquoElectric Power Systems Research vol 81 no 7 pp 1475ndash14812011
[10] P P Bedekar and S R Bhide ldquoOptimum coordination ofovercurrent relay timing using continuous genetic algorithmrdquoExpert Systems with Applications vol 38 no 9 pp 11286ndash112922011
[11] F Razavi H A Abyaneh M Al-Dabbagh R Mohammadiand H Torkaman ldquoA new comprehensive genetic algorithmmethod for optimal overcurrent relays coordinationrdquo ElectricPower Systems Research vol 78 no 4 pp 713ndash720 2008
[12] D E Goldberg Genetic Algorithms in Search Optimization andMachine Learning Addison-Wesley Reading Mass USA 1989
[13] D Adler ldquoGenetic algorithms and simulated annealing a mar-rage proposalrdquo in Proceedings of the IEEE International Confer-ence on Neural Networks vol 2 pp 1104ndash1109 1993
[14] K Premalatha and A M Natarajan ldquoHybrid PSO and GA forglobalmaximizationrdquo International Journal of Open Problems inComputer Science and Mathematics vol 2 no 4 2009
[15] H-J Lee G Son and J-W Park ldquoStudy on wind-turbine gen-erator system sizing considering voltage regulation and over-current relay coordinationrdquo IEEE Transactions on Power Sys-tems vol 26 no 3 pp 1283ndash1293 2011
10 ISRN Power Engineering
[16] T Amraee ldquoCoordination of directional overcurrent relaysusing seeker algorithmrdquo IEEE Transactions on Power Deliveryvol 27 no 3 pp 1415ndash1422 2012
[17] P P Bedekar and S R Bhide ldquoOptimum coordination of direc-tional overcurrent relays using the hybrid GA-NLP approachrdquoIEEE Transactions on Power Delivery vol 26 no 1 pp 109ndash1192011
[18] R M Chabanloo H A Abyaneh S S H Kamangar and FRazavi ldquoOptimal combined overcurrent and distance relayscoordination incorporating intelligent overcurrent relays char-acteristic selectionrdquo IEEE Transactions on Power Delivery vol26 no 3 pp 1381ndash1391 2011
[19] H Sharifian H A Abyaneh S K Salman R Mohammadiand F Razavi ldquoDetermination of the minimum break point setusing expert system and genetic algorithmrdquo IEEE Transactionson Power Delivery vol 25 no 3 pp 1284ndash1295 2010
[20] Power system test cases 1999 httpwwweewashingtoneduresearchpstcapf30ieee30cdftxt
[21] P G Slade J-L Wu E J Stacey et al ldquoThe utility requirementsfor a distribution fault current limiterrdquo IEEE Transactions onPower Delivery vol 7 no 2 pp 507ndash515 1992
[22] J R S S Kumara A Atputharajah J B Ekanayake and FJ Mumford ldquoOver current protection coordination of distri-bution networks with fault current limitersrdquo in Proceedings ofthe IEEE Power Engineering Society General Meeting (PES rsquo06)Montreal Canada 2006
International Journal of
AerospaceEngineeringHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
RoboticsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Active and Passive Electronic Components
Control Scienceand Engineering
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
International Journal of
RotatingMachinery
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporation httpwwwhindawicom
Journal ofEngineeringVolume 2014
Submit your manuscripts athttpwwwhindawicom
VLSI Design
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Shock and Vibration
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Civil EngineeringAdvances in
Acoustics and VibrationAdvances in
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Electrical and Computer Engineering
Journal of
Advances inOptoElectronics
Hindawi Publishing Corporation httpwwwhindawicom
Volume 2014
The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
SensorsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Modelling amp Simulation in EngineeringHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Chemical EngineeringInternational Journal of Antennas and
Propagation
International Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Navigation and Observation
International Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
DistributedSensor Networks
International Journal of
4 ISRN Power Engineering
prespecified fitness value If one of them is satisfied then thealgorithm terminates and goes to the next stage otherwise itreturns to the second step and starts the next iteration
5 Mathematical Overcurrent Relay Models
There are many mathematical models for the overcurrentrelays In this study the mathematical model of overcurrentrelays is considered to be the standard inverse type In thismathematical model the operating time of the overcurrentrelay is expressed as follows [16]
119905 =119896 times TMS(119894sc1198940)
119899
minus 1+ 119871 (4)
where 1198680is relay current setting 119868sc is short-circuit current
119879 is the relay operating time and TMS is the time multipliersetting of the relay TMS varies from 005 to 1 From the IECcurves for standard inverse type relays the parameters of (4)are assumed to be 119871 = 0 119896 = 014 and 119899 = 002
6 Comparison of the Results and Discussion
As described in Section 4 the values of the five coefficientsare variable so the output value of the objective function willnot be an appropriate criterion for comparing results of theproposed algorithm in [11] Therefore in order to gain thisaim two indicators are defined as follows
(i) Summation of TMSs If in a set of results of relay coor-dination there is not any miscoordination betweeneach two relays it can be said that the better coordina-tion has smaller summation of TMSs and therewithrelays have lower operating times
(ii) Summation of Difference between Each Time Opera-tion (sumΔ119905mb) For comparing two sets of the coor-dination results for example result 119860 and result 119861which do not have any miscoordination if value of(5) is true then the set of result 119860 is better than 119861Consider
119899
sum
(mb)=1(Δ119905(mb)119860 minus Δ119905(mb)119861) lt 0 (5)
In (5) the number of pairs of mainbackup (m b) relaysis equal to 119899 In this paper the proposed method is applied totwo different networks namely case study 1 and case study 2(case study 1 consists of 6 buses and case study 2 is the IEEE30-bus system) which are selected
61 Case Study 1 Network and Protection Information Casestudy 1 is 6-bus network shown in Figure 2 This networkconsists of 7 lines 6 buses 2 generators 2 transformers and14 overcurrent relays [17]
All the information about this network including short-circuit current of backup and main relays and relevant infor-mation relative to mainbackup relays have been provided in[11] and also are shown in Table 1
Table 1 Mainbackup pair information
Main relay Backup relay Primary relaySC current
Backup relaycurrent
8 9 4961 4108 7 4961 15202 7 5362 15282 1 5362 8043 2 3334 33344 3 2234 22345 4 1352 13526 5 4965 4116 14 4965 152214 1 4232 79414 9 4232 4071 6 2682 26829 10 1443 144310 11 2334 233411 12 3480 348012 14 5365 152912 13 5365 80513 8 2490 24907 5 4232 4077 13 4232 794
Table 2 119868119897max information
Relay number Maximum loadcurrent Relay number Maximum load
current1 416 8 4582 666 9 4503 500 10 4584 666 11 5415 458 12 4586 458 13 5007 541 14 666
Table 3 The input parameters of the optimization algorithm
Mutate range 03Crossover range 07Number of variables 19Number of population 100Maximum iteration 200Maximum subiteration GA 10Maximum subiteration PSO 10
Table 2 shows the maximum load current passingthrough the relays The way of the relay current settings isdescribed as follows [11]
1198680= 12 times 119868
119897max (6)
ISRN Power Engineering 5
R1
R2
R3R4
R5R6R7
R8R9
R10
R11R12R13
R14
sim
sim
Figure 2 Case study 1 network
32
21 61
63
22
18
46
3
12
44
4
49
95250
5
753483
64
62
23
84
82
41
20
1659
79
5442
85 8657
7
19 8
45 6
48
47
24 6725
68
69
65
70 26
56
12733376
7774
31
30
143855
58
15
39
81
4035
36
37
78
72
13
80
71
66
29
Figure 3 IEEE 30-bus system
6 ISRN Power Engineering
Table 4 The coordination results
Coordination output Reference [11] GAPSOTMS1
015 0066TMS2
035 01833TMS3
025 0146TMS4
01 0069TMS5
01 008TMS6
025 013TMS7
02 012TMS8
025 012TMS9
005 0095TMS10
015 0135TMS11
025 0174TMS12
04 0273TMS13
01 005TMS14
015 011199051
05894 0271199052
12173 0661199053
09621 0581199054
06636 0461199055
07660 0611199056
07623 041199057
07059 0431199058
07625 0371199059
03479 06611990510
06883 06411990511
09835 07111990512
11847 08211990513
04665 02411990514
05944 043Δ11990589
0 0Δ11990587
04673 0296Δ11990527
00028 0Δ11990521
06290 0Δ11990532
02657 0Δ11990543
02057 0Δ11990554
01885 0Δ11990565
0 0Δ119905614
04825 0418Δ119905141
13181 0258Δ119905149
0 0Δ11990516
00532 0Δ119905910
03173 0Δ1199051011
02195 0Δ1199051112
00492 0Δ1199051214
00489 0Δ1199051213
08135 0065Δ119905138
02292 0Δ11990575
0 0Δ119905713
14086 0511sumΔ119905 6699 155sumTMS 275 1741
Table 5 The object function parameters
1205721 251205722 01120573 15722119872 100119873 2
Table 6 Algorithm parameters information
Mutate range 03Crossover range 08Number of variables 91Number of population 200Maximum iteration 500Maximum subiteration GA 10Maximum subiteration PSO 10
All control parameters of algorithm are listed in Table 3The number of the variables in optimization problem is 19Fourteen of the variables are related to the TMS of the relaysand the remaining five variables are the coefficients of theobjective function that is 120573 120572
1 1205722119872119873
The results of the proposedmethod by GAPSO algorithmand the best results of [11] are compared in Table 4 The bestresults of [11] are shown in the second column of Table 4Thethird column of Table 4 represents feasible results for coordi-nation of the relays using the proposed method From Table4 all Δ119905mb values are small and positive and the largest Δ119905mbis 0511 secThe results mean there is not anymiscoordinationin the results Table 4 shows two superiority indicatorsthat is sumTMS and sumΔ119905mb optimized using the proposedalgorithm The first superiority indicator (sum119879119872119878) for theresults of [11] is 275 and for the proposed method is 1741and the second superiority indicator (sumΔ119905mb) for the resultsof [11] is 6699 sec and for the proposed method is 155 secThe superiority indicators show that the results would bemore optimized when the coefficients are optimized by theproposed algorithmThe advantage of thismethod is revealedwhen this new method is compared with the result of [11] inwhich the parameters are set manually in Table 4
With attend to Table 4 more relays operating time thatare earn from proposed method are smaller than [11] Forexample 119905
2in the proposedmethod is 066 seconds and in [11]
is 12173 seconds or 11990512
in proposed method is 082 secondsand in [11] is 11847 sec Also the values of the five parametersof objective function are shown in Table 5
62 Case Study 2 Network and Protection Information Forthe other test case 30-bus IEEE network is considered Thisnetwork has 86 OC relays It consists of 30 buses (132- and33-kV buses) 37 lines 6 generators 4 transformers and86OC relays [18] The distribution section of network thatwill be studied here is shown in Figure 3 [19] The generatortransmission lines and transformer information are givenfrom [20]
ISRN Power Engineering 7
Table 7 Coordination output results
Relay number 119879 TMS1 03092 01172 03092 01173 03467 01194 02095 00685 07561 01026 05671 02277 0248 00918 07271 01899 05679 010710 06679 024511 067 024112 0423 016013 0621 019514 09412 02515 09268 017016 02343 007417 05493 013918 05749 019019 03947 010520 05669 016321 02716 005922 05094 009023 05468 013924 07716 014225 07482 021726 06391 023927 06033 020328 06351 018429 06351 018430 06358 018331 04274 008832 05374 011833 0252 009034 02694 008935 03322 008436 08262 017437 04902 010638 01732 00539 01731 006140 01627 006841 06102 012342 02748 011543 0656 02544 02103 007645 02249 008446 0397 008147 01756 005648 05501 0179
Table 7 Continued
Relay number 119879 TMS49 07792 015550 01803 006151 0654 021152 06578 016653 06173 012954 05556 009355 10366 022456 05839 014358 06095 017659 02618 006560 04635 012961 02769 005662 03095 006163 03954 006664 05534 012865 03576 009466 05278 009967 05855 009968 07435 016169 05109 009570 06543 011371 02269 007872 0477 014373 02072 007074 06521 020475 03362 010476 05226 011577 02853 007378 04494 011680 04341 013781 03934 011182 08588 015483 09303 020284 05091 007785 03488 014486 03566 0079
In this paper four different cases are simulated for asuitable comparison Three cases are simulated according tothemethod of [11] in which the objective function coefficientsare set manually and the last case is simulated according tothe method proposed in this paper in which the objectivefunction coefficients are not set before simulation and theoptimization results show the values of the coefficients Allcases are evaluated by HGAPSO algorithm and all controlparameters of algorithm are listed in Table 6 The parametersare considered the same as 4 test cases A number of variablesin new method are considered 91 86 variables for relaysnumber and 5 variables for (120573 120572
1 1205722119872119873) and for method
proposed in [11] are considered 86Firstly the results of the proposed method by GAPSOA
are shown in Tables 7 and 8 The first column of Table 7
8 ISRN Power Engineering
Table 8 Time difference for each pair of MB relays
Δ11990541
03529 Δ1199051816
00021 Δ119905344
0 Δ1199051557
0 Δ1199055671
00122Δ11990561
0 Δ1199051916
01591 Δ119905145
00337 Δ1199055557
0 Δ1199055871
00025Δ11990571
03146 Δ1199052016
0 Δ119905345
0 Δ1199051458
01002 Δ1199052672
0Δ119905451
03418 Δ1199052118
10402 Δ119905146
0 Δ1199055558
0 Δ1199052772
0Δ11990542
03529 Δ1199052319
0 Δ119905246
0 Δ119905859
0 Δ1199052872
0Δ11990562
0 Δ1199053219
00027 Δ119905647
0 Δ1199054759
05927 Δ1199053072
0Δ11990572
03146 Δ1199056419
0 Δ119905747
03238 Δ1199054859
01788 Δ1199055672
0Δ119905442
03565 Δ1199052220
05459 Δ1199054447
03147 Δ1199051860
0 Δ1199055872
0Δ11990553
0 Δ1199052321
00023 Δ1199054547
03 Δ1199051960
01665 Δ1199052673
00003Δ11990584
0 Δ1199053221
0 Δ1199054648
0 Δ1199052060
00008 Δ1199052773
0Δ119905164
056 Δ1199056221
02384 Δ119905449
0 Δ1199055960
03069 Δ1199052873
0Δ119905484
01792 Δ1199057022
0 Δ119905749
0 Δ1199051761
0 Δ1199052973
0Δ11990585
0 Δ1199052423
03009 Δ1199054449
0 Δ1199051961
0 Δ1199055673
00081Δ119905165
05385 Δ1199052524
0 Δ1199054549
0 Δ1199052061
0 Δ1199055873
0Δ119905475
05848 Δ1199056925
0 Δ119905450
03518 Δ1199055961
0 Δ1199057174
02501Δ11990596
06558 Δ1199056826
04949 Δ119905650
0 Δ1199051762
0 Δ1199057274
0Δ119905107
0015 Δ1199056527
02957 Δ1199054450
03118 Δ1199051862
00312 Δ1199052375
00048Δ119905117
0 Δ1199053128
0 Δ1199054550
02971 Δ1199052062
00022 Δ1199056275
02319Δ119905127
02883 Δ1199057228
0 Δ1199051651
03311 Δ1199055962
03093 Δ1199056475
0Δ119905137
00488 Δ1199053129
0 Δ1199054751
03843 Δ1199051763
0 Δ1199057376
04701Δ119905437
00184 Δ1199057129
0 Δ1199054851
0 Δ1199051863
00059 Δ1199057476
0Δ119905517
00165 Δ1199053330
0 Δ1199054952
0 Δ1199051963
01605 Δ1199057577
0Δ119905108
00076 Δ1199057430
0 Δ1199051153
0 Δ1199055963
03125 Δ1199057678
0Δ119905118
0 Δ1199053331
0 Δ1199051253
02759 Δ1199056164
0 Δ1199057778
0Δ119905128
02671 Δ1199057331
00514 Δ1199051353
00489 Δ1199056365
0 Δ1199053779
0Δ119905138
00494 Δ1199053432
06332 Δ1199054353
00171 Δ1199053266
00072 Δ1199057879
02437Δ119905438
00161 Δ1199053533
0 Δ1199055053
05228 Δ1199056266
02319 Δ1199053680
0Δ119905508
05093 Δ1199057733
00416 Δ1199055153
00163 Δ1199056466
0 Δ1199057880
03633Δ119905539
0 Δ1199053534
02067 Δ1199051054
0 Δ1199056667
0 Δ1199058581
0Δ1199055210
00881 Δ1199057634
0 Δ1199051254
0 Δ1199056768
0 Δ1199058681
0Δ1199054211
03288 Δ1199053635
0 Δ1199051354
0 Δ1199052769
00239 Δ1199054082
0Δ1199051412
00006 Δ1199053735
02988 Δ1199054354
0 Δ1199052869
0 Δ1199058082
0Δ1199051512
0 Δ1199053937
02264 Δ1199055054
0 Δ1199052969
0 Δ1199058182
0Δ1199052613
0005 Δ1199054037
02523 Δ1199055154
0 Δ1199053069
00006 Δ1199053983
0Δ1199052713
0027 Δ1199058137
0 Δ1199051055
0 Δ1199055669
00331 Δ1199058083
0Δ1199052813
00001 Δ1199053938
03152 Δ1199051155
0 Δ1199055869
00202 Δ1199058183
0Δ1199052913
00001 Δ1199054038
03684 Δ1199051355
0 Δ1199052670
00155 Δ1199058284
0Δ1199053013
0 Δ1199058038
00055 Δ1199054355
0 Δ1199052870
0 Δ1199055485
0Δ1199055813
00262 Δ1199054139
0 Δ1199055055
0 Δ1199052970
0 Δ1199051086
0Δ1199052615
0 Δ1199058440
0 Δ1199055155
0 Δ1199053070
00003 Δ1199051186
00116Δ1199052715
0 Δ1199058341
0 Δ1199051056
00082 Δ1199055670
00368 Δ1199051286
02807Δ1199052815
0 Δ1199053842
01969 Δ1199051156
0 Δ1199055870
00215 Δ1199051386
00363Δ1199052915
0 Δ1199058642
0 Δ1199051256
02863 Δ1199052671
0 Δ1199055086
05105Δ1199053015
0 Δ1199053843
05089 Δ1199054356
00169 Δ1199052771
00031 Δ1199055186
0Δ1199055615
0 Δ1199058543
03278 Δ1199055056
05088 Δ1199052971
00142Δ1199051716
00001 Δ119905244
00333 Δ1199055156
00146 Δ1199053071
0006
shows relay number the second column (119879) shows relayoperating time for a fault close to the circuit breaker ofeach relay and the third column indicates the TMS of therelays From Table 8 all of the values of Δ119905mb are small andpositive numbers The positive values of Δ119905mb show that
there is no miscoordination in the results For example Δ11990541
refers to the relay pairs (4 and 1) that are obtained at 03529seconds The values of the five coefficients of the objectivefunction 120573 120572
1 1205722 119872 and 119873 are obtained as 5855 15 5
125 and 6 respectively When a fault occurs at downstream
ISRN Power Engineering 9
Table 9 Comparison between the proposed method and themethod of [11]
Case 1 Case 2 Case 3 Case 4120573 = 1 120573 = 10 120573 = 10 120573 = 58551205721= 1 120572
1= 10 120572
1= 1 120572
1= 15
1205722= 100 120572
2= 1 120572
2= 10 120572
2= 5
119872 = 2 119872 = 2 119872 = 2 119872 = 125N = 2 N = 2 N = 2 N = 6
sumΔ119905 298211 24115 269 2219sumTMS 1515 1455 156 1132
operating time of the downstreamprotective relays would notbe affected [21] In current grading the pickup current waschosen by considering the maximum possible load currentdue to normal overloading or contingency conditions Theloads of the buses 11 and 26 are the static types and thereis no need to install overcurrent relays on these buses SoTMSs of relays 57 and 79 that are connected to these buses areconsidered to be 005 [22] and other TMSs were calculated
In Table 9 the results of the simulations for the four casesare illustrated In this table the first row shows the fourdifferent cases and the second and the third rows show theresults of the first index (sumΔ119905) and the second index (sumTMS)for these cases The three first cases are related to the methodof [11] where in these cases the coefficients of the objectivefunction are set before optimization processThe values of thecoefficients are shown in the first column of the tableThe lastcase shows the results of the proposed method The values ofΔ119905 in all cases are positive and have not any miscoordination
The advantage of the proposed method is revealed whenthe results of the proposed method (Case 4) are comparedwith the best results of the traditional method of [11]According to Table 9 the best sumTMS and sumΔ119905 of method[11] (between three cases 1 and 2 and 3) are 1455 and24115 respectively whereassumTMS andsumΔt of the proposedmethod are 1132 and 2219 respectively This means thatthe results of Case 4 related to the new proposed methodshow the best coordination So considering the coefficientsof objective function as a part of the optimization prob-lem results are better compared with conventional methodaccording to the results of Tables 4 and 9
7 Conclusion
In this paper a new flexible technique for overcurrent relayscoordination has been proposed In this new technique thecoefficients of the conventional objective functions have beenimproved by optimization problem to obtain the minimumvalues for the TMSs of the relays In the proposed tech-nique GAPSOA optimization method is used to solve theoptimization problem This proposed method is tested on 6-bus case study and 30-bus IEEE case study The results ofthe simulation show the flexibility of the technique and thebest reliability because of the smallest sumTMS and sumΔ119905mbcompared to the conventional coordination methods
Conflict of Interests
The authors declare that there is no conflict of interestsregarding the publication of this paper
References
[1] R Mohammadi H A Abyaneh F Razavi M Al-Dabbaghand S H H Sadeghi ldquoOptimal relays coordination efficientmethod in interconnected power systemsrdquo Journal of ElectricalEngineering vol 61 no 2 pp 75ndash83 2010
[2] K Mazlumi and H A Abyaneh ldquoRelay coordination and pro-tection failure effects on reliability indices in an interconnectedsub-transmission systemrdquo Electric Power Systems Research vol79 no 7 pp 1011ndash1017 2009
[3] D Birla R P Maheshwari and H O Gupta ldquoTime overcurrentrelay coordination a reviewrdquo International Journal of EmergingElectric Power Systems vol 2 no 2 2005
[4] M Ojaghi Z Sudi and J Faiz ldquoImplementation of full adaptivetechnique to optimal coordination of overcurrent relaysrdquo IEEETransactions on Power Delivery vol 28 no 1 pp 235ndash244 2013
[5] C W So and K K Li ldquoOvercurrent relay coordination byevolutionary programmingrdquo Electric Power Systems Researchvol 53 no 2 pp 83ndash90 2000
[6] CW So K K Li K T Lai and K Y Fung ldquoApplication of gen-etic algorithm for overcurrent relay coordinationrdquo in Proceed-ings of the 6th International Conference on Developments inPower System Protection pp 66ndash69 1997
[7] C W So and K K Li ldquoTime coordination method for powersystem protection by evolutionary algorithmrdquo IEEE Transac-tions on Industry Applications vol 36 no 5 pp 1235ndash12402000
[8] J A Sueiro E Diaz-Dorado E Miguez and J Cidras ldquoCoordi-nation of directional overcurrent relay using evolutionary algo-rithm and linear programmingrdquo International Journal of Elec-trical Power amp Energy Systems vol 42 no 1 pp 299ndash305 2012
[9] M Ezzeddine and R Kaczmarek ldquoA novel method for optimalcoordination of directional overcurrent relays considering theiravailable discrete settings and several operation characteristicsrdquoElectric Power Systems Research vol 81 no 7 pp 1475ndash14812011
[10] P P Bedekar and S R Bhide ldquoOptimum coordination ofovercurrent relay timing using continuous genetic algorithmrdquoExpert Systems with Applications vol 38 no 9 pp 11286ndash112922011
[11] F Razavi H A Abyaneh M Al-Dabbagh R Mohammadiand H Torkaman ldquoA new comprehensive genetic algorithmmethod for optimal overcurrent relays coordinationrdquo ElectricPower Systems Research vol 78 no 4 pp 713ndash720 2008
[12] D E Goldberg Genetic Algorithms in Search Optimization andMachine Learning Addison-Wesley Reading Mass USA 1989
[13] D Adler ldquoGenetic algorithms and simulated annealing a mar-rage proposalrdquo in Proceedings of the IEEE International Confer-ence on Neural Networks vol 2 pp 1104ndash1109 1993
[14] K Premalatha and A M Natarajan ldquoHybrid PSO and GA forglobalmaximizationrdquo International Journal of Open Problems inComputer Science and Mathematics vol 2 no 4 2009
[15] H-J Lee G Son and J-W Park ldquoStudy on wind-turbine gen-erator system sizing considering voltage regulation and over-current relay coordinationrdquo IEEE Transactions on Power Sys-tems vol 26 no 3 pp 1283ndash1293 2011
10 ISRN Power Engineering
[16] T Amraee ldquoCoordination of directional overcurrent relaysusing seeker algorithmrdquo IEEE Transactions on Power Deliveryvol 27 no 3 pp 1415ndash1422 2012
[17] P P Bedekar and S R Bhide ldquoOptimum coordination of direc-tional overcurrent relays using the hybrid GA-NLP approachrdquoIEEE Transactions on Power Delivery vol 26 no 1 pp 109ndash1192011
[18] R M Chabanloo H A Abyaneh S S H Kamangar and FRazavi ldquoOptimal combined overcurrent and distance relayscoordination incorporating intelligent overcurrent relays char-acteristic selectionrdquo IEEE Transactions on Power Delivery vol26 no 3 pp 1381ndash1391 2011
[19] H Sharifian H A Abyaneh S K Salman R Mohammadiand F Razavi ldquoDetermination of the minimum break point setusing expert system and genetic algorithmrdquo IEEE Transactionson Power Delivery vol 25 no 3 pp 1284ndash1295 2010
[20] Power system test cases 1999 httpwwweewashingtoneduresearchpstcapf30ieee30cdftxt
[21] P G Slade J-L Wu E J Stacey et al ldquoThe utility requirementsfor a distribution fault current limiterrdquo IEEE Transactions onPower Delivery vol 7 no 2 pp 507ndash515 1992
[22] J R S S Kumara A Atputharajah J B Ekanayake and FJ Mumford ldquoOver current protection coordination of distri-bution networks with fault current limitersrdquo in Proceedings ofthe IEEE Power Engineering Society General Meeting (PES rsquo06)Montreal Canada 2006
International Journal of
AerospaceEngineeringHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
RoboticsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Active and Passive Electronic Components
Control Scienceand Engineering
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
International Journal of
RotatingMachinery
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporation httpwwwhindawicom
Journal ofEngineeringVolume 2014
Submit your manuscripts athttpwwwhindawicom
VLSI Design
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Shock and Vibration
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Civil EngineeringAdvances in
Acoustics and VibrationAdvances in
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Electrical and Computer Engineering
Journal of
Advances inOptoElectronics
Hindawi Publishing Corporation httpwwwhindawicom
Volume 2014
The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
SensorsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Modelling amp Simulation in EngineeringHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Chemical EngineeringInternational Journal of Antennas and
Propagation
International Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Navigation and Observation
International Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
DistributedSensor Networks
International Journal of
ISRN Power Engineering 5
R1
R2
R3R4
R5R6R7
R8R9
R10
R11R12R13
R14
sim
sim
Figure 2 Case study 1 network
32
21 61
63
22
18
46
3
12
44
4
49
95250
5
753483
64
62
23
84
82
41
20
1659
79
5442
85 8657
7
19 8
45 6
48
47
24 6725
68
69
65
70 26
56
12733376
7774
31
30
143855
58
15
39
81
4035
36
37
78
72
13
80
71
66
29
Figure 3 IEEE 30-bus system
6 ISRN Power Engineering
Table 4 The coordination results
Coordination output Reference [11] GAPSOTMS1
015 0066TMS2
035 01833TMS3
025 0146TMS4
01 0069TMS5
01 008TMS6
025 013TMS7
02 012TMS8
025 012TMS9
005 0095TMS10
015 0135TMS11
025 0174TMS12
04 0273TMS13
01 005TMS14
015 011199051
05894 0271199052
12173 0661199053
09621 0581199054
06636 0461199055
07660 0611199056
07623 041199057
07059 0431199058
07625 0371199059
03479 06611990510
06883 06411990511
09835 07111990512
11847 08211990513
04665 02411990514
05944 043Δ11990589
0 0Δ11990587
04673 0296Δ11990527
00028 0Δ11990521
06290 0Δ11990532
02657 0Δ11990543
02057 0Δ11990554
01885 0Δ11990565
0 0Δ119905614
04825 0418Δ119905141
13181 0258Δ119905149
0 0Δ11990516
00532 0Δ119905910
03173 0Δ1199051011
02195 0Δ1199051112
00492 0Δ1199051214
00489 0Δ1199051213
08135 0065Δ119905138
02292 0Δ11990575
0 0Δ119905713
14086 0511sumΔ119905 6699 155sumTMS 275 1741
Table 5 The object function parameters
1205721 251205722 01120573 15722119872 100119873 2
Table 6 Algorithm parameters information
Mutate range 03Crossover range 08Number of variables 91Number of population 200Maximum iteration 500Maximum subiteration GA 10Maximum subiteration PSO 10
All control parameters of algorithm are listed in Table 3The number of the variables in optimization problem is 19Fourteen of the variables are related to the TMS of the relaysand the remaining five variables are the coefficients of theobjective function that is 120573 120572
1 1205722119872119873
The results of the proposedmethod by GAPSO algorithmand the best results of [11] are compared in Table 4 The bestresults of [11] are shown in the second column of Table 4Thethird column of Table 4 represents feasible results for coordi-nation of the relays using the proposed method From Table4 all Δ119905mb values are small and positive and the largest Δ119905mbis 0511 secThe results mean there is not anymiscoordinationin the results Table 4 shows two superiority indicatorsthat is sumTMS and sumΔ119905mb optimized using the proposedalgorithm The first superiority indicator (sum119879119872119878) for theresults of [11] is 275 and for the proposed method is 1741and the second superiority indicator (sumΔ119905mb) for the resultsof [11] is 6699 sec and for the proposed method is 155 secThe superiority indicators show that the results would bemore optimized when the coefficients are optimized by theproposed algorithmThe advantage of thismethod is revealedwhen this new method is compared with the result of [11] inwhich the parameters are set manually in Table 4
With attend to Table 4 more relays operating time thatare earn from proposed method are smaller than [11] Forexample 119905
2in the proposedmethod is 066 seconds and in [11]
is 12173 seconds or 11990512
in proposed method is 082 secondsand in [11] is 11847 sec Also the values of the five parametersof objective function are shown in Table 5
62 Case Study 2 Network and Protection Information Forthe other test case 30-bus IEEE network is considered Thisnetwork has 86 OC relays It consists of 30 buses (132- and33-kV buses) 37 lines 6 generators 4 transformers and86OC relays [18] The distribution section of network thatwill be studied here is shown in Figure 3 [19] The generatortransmission lines and transformer information are givenfrom [20]
ISRN Power Engineering 7
Table 7 Coordination output results
Relay number 119879 TMS1 03092 01172 03092 01173 03467 01194 02095 00685 07561 01026 05671 02277 0248 00918 07271 01899 05679 010710 06679 024511 067 024112 0423 016013 0621 019514 09412 02515 09268 017016 02343 007417 05493 013918 05749 019019 03947 010520 05669 016321 02716 005922 05094 009023 05468 013924 07716 014225 07482 021726 06391 023927 06033 020328 06351 018429 06351 018430 06358 018331 04274 008832 05374 011833 0252 009034 02694 008935 03322 008436 08262 017437 04902 010638 01732 00539 01731 006140 01627 006841 06102 012342 02748 011543 0656 02544 02103 007645 02249 008446 0397 008147 01756 005648 05501 0179
Table 7 Continued
Relay number 119879 TMS49 07792 015550 01803 006151 0654 021152 06578 016653 06173 012954 05556 009355 10366 022456 05839 014358 06095 017659 02618 006560 04635 012961 02769 005662 03095 006163 03954 006664 05534 012865 03576 009466 05278 009967 05855 009968 07435 016169 05109 009570 06543 011371 02269 007872 0477 014373 02072 007074 06521 020475 03362 010476 05226 011577 02853 007378 04494 011680 04341 013781 03934 011182 08588 015483 09303 020284 05091 007785 03488 014486 03566 0079
In this paper four different cases are simulated for asuitable comparison Three cases are simulated according tothemethod of [11] in which the objective function coefficientsare set manually and the last case is simulated according tothe method proposed in this paper in which the objectivefunction coefficients are not set before simulation and theoptimization results show the values of the coefficients Allcases are evaluated by HGAPSO algorithm and all controlparameters of algorithm are listed in Table 6 The parametersare considered the same as 4 test cases A number of variablesin new method are considered 91 86 variables for relaysnumber and 5 variables for (120573 120572
1 1205722119872119873) and for method
proposed in [11] are considered 86Firstly the results of the proposed method by GAPSOA
are shown in Tables 7 and 8 The first column of Table 7
8 ISRN Power Engineering
Table 8 Time difference for each pair of MB relays
Δ11990541
03529 Δ1199051816
00021 Δ119905344
0 Δ1199051557
0 Δ1199055671
00122Δ11990561
0 Δ1199051916
01591 Δ119905145
00337 Δ1199055557
0 Δ1199055871
00025Δ11990571
03146 Δ1199052016
0 Δ119905345
0 Δ1199051458
01002 Δ1199052672
0Δ119905451
03418 Δ1199052118
10402 Δ119905146
0 Δ1199055558
0 Δ1199052772
0Δ11990542
03529 Δ1199052319
0 Δ119905246
0 Δ119905859
0 Δ1199052872
0Δ11990562
0 Δ1199053219
00027 Δ119905647
0 Δ1199054759
05927 Δ1199053072
0Δ11990572
03146 Δ1199056419
0 Δ119905747
03238 Δ1199054859
01788 Δ1199055672
0Δ119905442
03565 Δ1199052220
05459 Δ1199054447
03147 Δ1199051860
0 Δ1199055872
0Δ11990553
0 Δ1199052321
00023 Δ1199054547
03 Δ1199051960
01665 Δ1199052673
00003Δ11990584
0 Δ1199053221
0 Δ1199054648
0 Δ1199052060
00008 Δ1199052773
0Δ119905164
056 Δ1199056221
02384 Δ119905449
0 Δ1199055960
03069 Δ1199052873
0Δ119905484
01792 Δ1199057022
0 Δ119905749
0 Δ1199051761
0 Δ1199052973
0Δ11990585
0 Δ1199052423
03009 Δ1199054449
0 Δ1199051961
0 Δ1199055673
00081Δ119905165
05385 Δ1199052524
0 Δ1199054549
0 Δ1199052061
0 Δ1199055873
0Δ119905475
05848 Δ1199056925
0 Δ119905450
03518 Δ1199055961
0 Δ1199057174
02501Δ11990596
06558 Δ1199056826
04949 Δ119905650
0 Δ1199051762
0 Δ1199057274
0Δ119905107
0015 Δ1199056527
02957 Δ1199054450
03118 Δ1199051862
00312 Δ1199052375
00048Δ119905117
0 Δ1199053128
0 Δ1199054550
02971 Δ1199052062
00022 Δ1199056275
02319Δ119905127
02883 Δ1199057228
0 Δ1199051651
03311 Δ1199055962
03093 Δ1199056475
0Δ119905137
00488 Δ1199053129
0 Δ1199054751
03843 Δ1199051763
0 Δ1199057376
04701Δ119905437
00184 Δ1199057129
0 Δ1199054851
0 Δ1199051863
00059 Δ1199057476
0Δ119905517
00165 Δ1199053330
0 Δ1199054952
0 Δ1199051963
01605 Δ1199057577
0Δ119905108
00076 Δ1199057430
0 Δ1199051153
0 Δ1199055963
03125 Δ1199057678
0Δ119905118
0 Δ1199053331
0 Δ1199051253
02759 Δ1199056164
0 Δ1199057778
0Δ119905128
02671 Δ1199057331
00514 Δ1199051353
00489 Δ1199056365
0 Δ1199053779
0Δ119905138
00494 Δ1199053432
06332 Δ1199054353
00171 Δ1199053266
00072 Δ1199057879
02437Δ119905438
00161 Δ1199053533
0 Δ1199055053
05228 Δ1199056266
02319 Δ1199053680
0Δ119905508
05093 Δ1199057733
00416 Δ1199055153
00163 Δ1199056466
0 Δ1199057880
03633Δ119905539
0 Δ1199053534
02067 Δ1199051054
0 Δ1199056667
0 Δ1199058581
0Δ1199055210
00881 Δ1199057634
0 Δ1199051254
0 Δ1199056768
0 Δ1199058681
0Δ1199054211
03288 Δ1199053635
0 Δ1199051354
0 Δ1199052769
00239 Δ1199054082
0Δ1199051412
00006 Δ1199053735
02988 Δ1199054354
0 Δ1199052869
0 Δ1199058082
0Δ1199051512
0 Δ1199053937
02264 Δ1199055054
0 Δ1199052969
0 Δ1199058182
0Δ1199052613
0005 Δ1199054037
02523 Δ1199055154
0 Δ1199053069
00006 Δ1199053983
0Δ1199052713
0027 Δ1199058137
0 Δ1199051055
0 Δ1199055669
00331 Δ1199058083
0Δ1199052813
00001 Δ1199053938
03152 Δ1199051155
0 Δ1199055869
00202 Δ1199058183
0Δ1199052913
00001 Δ1199054038
03684 Δ1199051355
0 Δ1199052670
00155 Δ1199058284
0Δ1199053013
0 Δ1199058038
00055 Δ1199054355
0 Δ1199052870
0 Δ1199055485
0Δ1199055813
00262 Δ1199054139
0 Δ1199055055
0 Δ1199052970
0 Δ1199051086
0Δ1199052615
0 Δ1199058440
0 Δ1199055155
0 Δ1199053070
00003 Δ1199051186
00116Δ1199052715
0 Δ1199058341
0 Δ1199051056
00082 Δ1199055670
00368 Δ1199051286
02807Δ1199052815
0 Δ1199053842
01969 Δ1199051156
0 Δ1199055870
00215 Δ1199051386
00363Δ1199052915
0 Δ1199058642
0 Δ1199051256
02863 Δ1199052671
0 Δ1199055086
05105Δ1199053015
0 Δ1199053843
05089 Δ1199054356
00169 Δ1199052771
00031 Δ1199055186
0Δ1199055615
0 Δ1199058543
03278 Δ1199055056
05088 Δ1199052971
00142Δ1199051716
00001 Δ119905244
00333 Δ1199055156
00146 Δ1199053071
0006
shows relay number the second column (119879) shows relayoperating time for a fault close to the circuit breaker ofeach relay and the third column indicates the TMS of therelays From Table 8 all of the values of Δ119905mb are small andpositive numbers The positive values of Δ119905mb show that
there is no miscoordination in the results For example Δ11990541
refers to the relay pairs (4 and 1) that are obtained at 03529seconds The values of the five coefficients of the objectivefunction 120573 120572
1 1205722 119872 and 119873 are obtained as 5855 15 5
125 and 6 respectively When a fault occurs at downstream
ISRN Power Engineering 9
Table 9 Comparison between the proposed method and themethod of [11]
Case 1 Case 2 Case 3 Case 4120573 = 1 120573 = 10 120573 = 10 120573 = 58551205721= 1 120572
1= 10 120572
1= 1 120572
1= 15
1205722= 100 120572
2= 1 120572
2= 10 120572
2= 5
119872 = 2 119872 = 2 119872 = 2 119872 = 125N = 2 N = 2 N = 2 N = 6
sumΔ119905 298211 24115 269 2219sumTMS 1515 1455 156 1132
operating time of the downstreamprotective relays would notbe affected [21] In current grading the pickup current waschosen by considering the maximum possible load currentdue to normal overloading or contingency conditions Theloads of the buses 11 and 26 are the static types and thereis no need to install overcurrent relays on these buses SoTMSs of relays 57 and 79 that are connected to these buses areconsidered to be 005 [22] and other TMSs were calculated
In Table 9 the results of the simulations for the four casesare illustrated In this table the first row shows the fourdifferent cases and the second and the third rows show theresults of the first index (sumΔ119905) and the second index (sumTMS)for these cases The three first cases are related to the methodof [11] where in these cases the coefficients of the objectivefunction are set before optimization processThe values of thecoefficients are shown in the first column of the tableThe lastcase shows the results of the proposed method The values ofΔ119905 in all cases are positive and have not any miscoordination
The advantage of the proposed method is revealed whenthe results of the proposed method (Case 4) are comparedwith the best results of the traditional method of [11]According to Table 9 the best sumTMS and sumΔ119905 of method[11] (between three cases 1 and 2 and 3) are 1455 and24115 respectively whereassumTMS andsumΔt of the proposedmethod are 1132 and 2219 respectively This means thatthe results of Case 4 related to the new proposed methodshow the best coordination So considering the coefficientsof objective function as a part of the optimization prob-lem results are better compared with conventional methodaccording to the results of Tables 4 and 9
7 Conclusion
In this paper a new flexible technique for overcurrent relayscoordination has been proposed In this new technique thecoefficients of the conventional objective functions have beenimproved by optimization problem to obtain the minimumvalues for the TMSs of the relays In the proposed tech-nique GAPSOA optimization method is used to solve theoptimization problem This proposed method is tested on 6-bus case study and 30-bus IEEE case study The results ofthe simulation show the flexibility of the technique and thebest reliability because of the smallest sumTMS and sumΔ119905mbcompared to the conventional coordination methods
Conflict of Interests
The authors declare that there is no conflict of interestsregarding the publication of this paper
References
[1] R Mohammadi H A Abyaneh F Razavi M Al-Dabbaghand S H H Sadeghi ldquoOptimal relays coordination efficientmethod in interconnected power systemsrdquo Journal of ElectricalEngineering vol 61 no 2 pp 75ndash83 2010
[2] K Mazlumi and H A Abyaneh ldquoRelay coordination and pro-tection failure effects on reliability indices in an interconnectedsub-transmission systemrdquo Electric Power Systems Research vol79 no 7 pp 1011ndash1017 2009
[3] D Birla R P Maheshwari and H O Gupta ldquoTime overcurrentrelay coordination a reviewrdquo International Journal of EmergingElectric Power Systems vol 2 no 2 2005
[4] M Ojaghi Z Sudi and J Faiz ldquoImplementation of full adaptivetechnique to optimal coordination of overcurrent relaysrdquo IEEETransactions on Power Delivery vol 28 no 1 pp 235ndash244 2013
[5] C W So and K K Li ldquoOvercurrent relay coordination byevolutionary programmingrdquo Electric Power Systems Researchvol 53 no 2 pp 83ndash90 2000
[6] CW So K K Li K T Lai and K Y Fung ldquoApplication of gen-etic algorithm for overcurrent relay coordinationrdquo in Proceed-ings of the 6th International Conference on Developments inPower System Protection pp 66ndash69 1997
[7] C W So and K K Li ldquoTime coordination method for powersystem protection by evolutionary algorithmrdquo IEEE Transac-tions on Industry Applications vol 36 no 5 pp 1235ndash12402000
[8] J A Sueiro E Diaz-Dorado E Miguez and J Cidras ldquoCoordi-nation of directional overcurrent relay using evolutionary algo-rithm and linear programmingrdquo International Journal of Elec-trical Power amp Energy Systems vol 42 no 1 pp 299ndash305 2012
[9] M Ezzeddine and R Kaczmarek ldquoA novel method for optimalcoordination of directional overcurrent relays considering theiravailable discrete settings and several operation characteristicsrdquoElectric Power Systems Research vol 81 no 7 pp 1475ndash14812011
[10] P P Bedekar and S R Bhide ldquoOptimum coordination ofovercurrent relay timing using continuous genetic algorithmrdquoExpert Systems with Applications vol 38 no 9 pp 11286ndash112922011
[11] F Razavi H A Abyaneh M Al-Dabbagh R Mohammadiand H Torkaman ldquoA new comprehensive genetic algorithmmethod for optimal overcurrent relays coordinationrdquo ElectricPower Systems Research vol 78 no 4 pp 713ndash720 2008
[12] D E Goldberg Genetic Algorithms in Search Optimization andMachine Learning Addison-Wesley Reading Mass USA 1989
[13] D Adler ldquoGenetic algorithms and simulated annealing a mar-rage proposalrdquo in Proceedings of the IEEE International Confer-ence on Neural Networks vol 2 pp 1104ndash1109 1993
[14] K Premalatha and A M Natarajan ldquoHybrid PSO and GA forglobalmaximizationrdquo International Journal of Open Problems inComputer Science and Mathematics vol 2 no 4 2009
[15] H-J Lee G Son and J-W Park ldquoStudy on wind-turbine gen-erator system sizing considering voltage regulation and over-current relay coordinationrdquo IEEE Transactions on Power Sys-tems vol 26 no 3 pp 1283ndash1293 2011
10 ISRN Power Engineering
[16] T Amraee ldquoCoordination of directional overcurrent relaysusing seeker algorithmrdquo IEEE Transactions on Power Deliveryvol 27 no 3 pp 1415ndash1422 2012
[17] P P Bedekar and S R Bhide ldquoOptimum coordination of direc-tional overcurrent relays using the hybrid GA-NLP approachrdquoIEEE Transactions on Power Delivery vol 26 no 1 pp 109ndash1192011
[18] R M Chabanloo H A Abyaneh S S H Kamangar and FRazavi ldquoOptimal combined overcurrent and distance relayscoordination incorporating intelligent overcurrent relays char-acteristic selectionrdquo IEEE Transactions on Power Delivery vol26 no 3 pp 1381ndash1391 2011
[19] H Sharifian H A Abyaneh S K Salman R Mohammadiand F Razavi ldquoDetermination of the minimum break point setusing expert system and genetic algorithmrdquo IEEE Transactionson Power Delivery vol 25 no 3 pp 1284ndash1295 2010
[20] Power system test cases 1999 httpwwweewashingtoneduresearchpstcapf30ieee30cdftxt
[21] P G Slade J-L Wu E J Stacey et al ldquoThe utility requirementsfor a distribution fault current limiterrdquo IEEE Transactions onPower Delivery vol 7 no 2 pp 507ndash515 1992
[22] J R S S Kumara A Atputharajah J B Ekanayake and FJ Mumford ldquoOver current protection coordination of distri-bution networks with fault current limitersrdquo in Proceedings ofthe IEEE Power Engineering Society General Meeting (PES rsquo06)Montreal Canada 2006
International Journal of
AerospaceEngineeringHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
RoboticsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Active and Passive Electronic Components
Control Scienceand Engineering
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
International Journal of
RotatingMachinery
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporation httpwwwhindawicom
Journal ofEngineeringVolume 2014
Submit your manuscripts athttpwwwhindawicom
VLSI Design
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Shock and Vibration
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Civil EngineeringAdvances in
Acoustics and VibrationAdvances in
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Electrical and Computer Engineering
Journal of
Advances inOptoElectronics
Hindawi Publishing Corporation httpwwwhindawicom
Volume 2014
The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
SensorsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Modelling amp Simulation in EngineeringHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Chemical EngineeringInternational Journal of Antennas and
Propagation
International Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Navigation and Observation
International Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
DistributedSensor Networks
International Journal of
6 ISRN Power Engineering
Table 4 The coordination results
Coordination output Reference [11] GAPSOTMS1
015 0066TMS2
035 01833TMS3
025 0146TMS4
01 0069TMS5
01 008TMS6
025 013TMS7
02 012TMS8
025 012TMS9
005 0095TMS10
015 0135TMS11
025 0174TMS12
04 0273TMS13
01 005TMS14
015 011199051
05894 0271199052
12173 0661199053
09621 0581199054
06636 0461199055
07660 0611199056
07623 041199057
07059 0431199058
07625 0371199059
03479 06611990510
06883 06411990511
09835 07111990512
11847 08211990513
04665 02411990514
05944 043Δ11990589
0 0Δ11990587
04673 0296Δ11990527
00028 0Δ11990521
06290 0Δ11990532
02657 0Δ11990543
02057 0Δ11990554
01885 0Δ11990565
0 0Δ119905614
04825 0418Δ119905141
13181 0258Δ119905149
0 0Δ11990516
00532 0Δ119905910
03173 0Δ1199051011
02195 0Δ1199051112
00492 0Δ1199051214
00489 0Δ1199051213
08135 0065Δ119905138
02292 0Δ11990575
0 0Δ119905713
14086 0511sumΔ119905 6699 155sumTMS 275 1741
Table 5 The object function parameters
1205721 251205722 01120573 15722119872 100119873 2
Table 6 Algorithm parameters information
Mutate range 03Crossover range 08Number of variables 91Number of population 200Maximum iteration 500Maximum subiteration GA 10Maximum subiteration PSO 10
All control parameters of algorithm are listed in Table 3The number of the variables in optimization problem is 19Fourteen of the variables are related to the TMS of the relaysand the remaining five variables are the coefficients of theobjective function that is 120573 120572
1 1205722119872119873
The results of the proposedmethod by GAPSO algorithmand the best results of [11] are compared in Table 4 The bestresults of [11] are shown in the second column of Table 4Thethird column of Table 4 represents feasible results for coordi-nation of the relays using the proposed method From Table4 all Δ119905mb values are small and positive and the largest Δ119905mbis 0511 secThe results mean there is not anymiscoordinationin the results Table 4 shows two superiority indicatorsthat is sumTMS and sumΔ119905mb optimized using the proposedalgorithm The first superiority indicator (sum119879119872119878) for theresults of [11] is 275 and for the proposed method is 1741and the second superiority indicator (sumΔ119905mb) for the resultsof [11] is 6699 sec and for the proposed method is 155 secThe superiority indicators show that the results would bemore optimized when the coefficients are optimized by theproposed algorithmThe advantage of thismethod is revealedwhen this new method is compared with the result of [11] inwhich the parameters are set manually in Table 4
With attend to Table 4 more relays operating time thatare earn from proposed method are smaller than [11] Forexample 119905
2in the proposedmethod is 066 seconds and in [11]
is 12173 seconds or 11990512
in proposed method is 082 secondsand in [11] is 11847 sec Also the values of the five parametersof objective function are shown in Table 5
62 Case Study 2 Network and Protection Information Forthe other test case 30-bus IEEE network is considered Thisnetwork has 86 OC relays It consists of 30 buses (132- and33-kV buses) 37 lines 6 generators 4 transformers and86OC relays [18] The distribution section of network thatwill be studied here is shown in Figure 3 [19] The generatortransmission lines and transformer information are givenfrom [20]
ISRN Power Engineering 7
Table 7 Coordination output results
Relay number 119879 TMS1 03092 01172 03092 01173 03467 01194 02095 00685 07561 01026 05671 02277 0248 00918 07271 01899 05679 010710 06679 024511 067 024112 0423 016013 0621 019514 09412 02515 09268 017016 02343 007417 05493 013918 05749 019019 03947 010520 05669 016321 02716 005922 05094 009023 05468 013924 07716 014225 07482 021726 06391 023927 06033 020328 06351 018429 06351 018430 06358 018331 04274 008832 05374 011833 0252 009034 02694 008935 03322 008436 08262 017437 04902 010638 01732 00539 01731 006140 01627 006841 06102 012342 02748 011543 0656 02544 02103 007645 02249 008446 0397 008147 01756 005648 05501 0179
Table 7 Continued
Relay number 119879 TMS49 07792 015550 01803 006151 0654 021152 06578 016653 06173 012954 05556 009355 10366 022456 05839 014358 06095 017659 02618 006560 04635 012961 02769 005662 03095 006163 03954 006664 05534 012865 03576 009466 05278 009967 05855 009968 07435 016169 05109 009570 06543 011371 02269 007872 0477 014373 02072 007074 06521 020475 03362 010476 05226 011577 02853 007378 04494 011680 04341 013781 03934 011182 08588 015483 09303 020284 05091 007785 03488 014486 03566 0079
In this paper four different cases are simulated for asuitable comparison Three cases are simulated according tothemethod of [11] in which the objective function coefficientsare set manually and the last case is simulated according tothe method proposed in this paper in which the objectivefunction coefficients are not set before simulation and theoptimization results show the values of the coefficients Allcases are evaluated by HGAPSO algorithm and all controlparameters of algorithm are listed in Table 6 The parametersare considered the same as 4 test cases A number of variablesin new method are considered 91 86 variables for relaysnumber and 5 variables for (120573 120572
1 1205722119872119873) and for method
proposed in [11] are considered 86Firstly the results of the proposed method by GAPSOA
are shown in Tables 7 and 8 The first column of Table 7
8 ISRN Power Engineering
Table 8 Time difference for each pair of MB relays
Δ11990541
03529 Δ1199051816
00021 Δ119905344
0 Δ1199051557
0 Δ1199055671
00122Δ11990561
0 Δ1199051916
01591 Δ119905145
00337 Δ1199055557
0 Δ1199055871
00025Δ11990571
03146 Δ1199052016
0 Δ119905345
0 Δ1199051458
01002 Δ1199052672
0Δ119905451
03418 Δ1199052118
10402 Δ119905146
0 Δ1199055558
0 Δ1199052772
0Δ11990542
03529 Δ1199052319
0 Δ119905246
0 Δ119905859
0 Δ1199052872
0Δ11990562
0 Δ1199053219
00027 Δ119905647
0 Δ1199054759
05927 Δ1199053072
0Δ11990572
03146 Δ1199056419
0 Δ119905747
03238 Δ1199054859
01788 Δ1199055672
0Δ119905442
03565 Δ1199052220
05459 Δ1199054447
03147 Δ1199051860
0 Δ1199055872
0Δ11990553
0 Δ1199052321
00023 Δ1199054547
03 Δ1199051960
01665 Δ1199052673
00003Δ11990584
0 Δ1199053221
0 Δ1199054648
0 Δ1199052060
00008 Δ1199052773
0Δ119905164
056 Δ1199056221
02384 Δ119905449
0 Δ1199055960
03069 Δ1199052873
0Δ119905484
01792 Δ1199057022
0 Δ119905749
0 Δ1199051761
0 Δ1199052973
0Δ11990585
0 Δ1199052423
03009 Δ1199054449
0 Δ1199051961
0 Δ1199055673
00081Δ119905165
05385 Δ1199052524
0 Δ1199054549
0 Δ1199052061
0 Δ1199055873
0Δ119905475
05848 Δ1199056925
0 Δ119905450
03518 Δ1199055961
0 Δ1199057174
02501Δ11990596
06558 Δ1199056826
04949 Δ119905650
0 Δ1199051762
0 Δ1199057274
0Δ119905107
0015 Δ1199056527
02957 Δ1199054450
03118 Δ1199051862
00312 Δ1199052375
00048Δ119905117
0 Δ1199053128
0 Δ1199054550
02971 Δ1199052062
00022 Δ1199056275
02319Δ119905127
02883 Δ1199057228
0 Δ1199051651
03311 Δ1199055962
03093 Δ1199056475
0Δ119905137
00488 Δ1199053129
0 Δ1199054751
03843 Δ1199051763
0 Δ1199057376
04701Δ119905437
00184 Δ1199057129
0 Δ1199054851
0 Δ1199051863
00059 Δ1199057476
0Δ119905517
00165 Δ1199053330
0 Δ1199054952
0 Δ1199051963
01605 Δ1199057577
0Δ119905108
00076 Δ1199057430
0 Δ1199051153
0 Δ1199055963
03125 Δ1199057678
0Δ119905118
0 Δ1199053331
0 Δ1199051253
02759 Δ1199056164
0 Δ1199057778
0Δ119905128
02671 Δ1199057331
00514 Δ1199051353
00489 Δ1199056365
0 Δ1199053779
0Δ119905138
00494 Δ1199053432
06332 Δ1199054353
00171 Δ1199053266
00072 Δ1199057879
02437Δ119905438
00161 Δ1199053533
0 Δ1199055053
05228 Δ1199056266
02319 Δ1199053680
0Δ119905508
05093 Δ1199057733
00416 Δ1199055153
00163 Δ1199056466
0 Δ1199057880
03633Δ119905539
0 Δ1199053534
02067 Δ1199051054
0 Δ1199056667
0 Δ1199058581
0Δ1199055210
00881 Δ1199057634
0 Δ1199051254
0 Δ1199056768
0 Δ1199058681
0Δ1199054211
03288 Δ1199053635
0 Δ1199051354
0 Δ1199052769
00239 Δ1199054082
0Δ1199051412
00006 Δ1199053735
02988 Δ1199054354
0 Δ1199052869
0 Δ1199058082
0Δ1199051512
0 Δ1199053937
02264 Δ1199055054
0 Δ1199052969
0 Δ1199058182
0Δ1199052613
0005 Δ1199054037
02523 Δ1199055154
0 Δ1199053069
00006 Δ1199053983
0Δ1199052713
0027 Δ1199058137
0 Δ1199051055
0 Δ1199055669
00331 Δ1199058083
0Δ1199052813
00001 Δ1199053938
03152 Δ1199051155
0 Δ1199055869
00202 Δ1199058183
0Δ1199052913
00001 Δ1199054038
03684 Δ1199051355
0 Δ1199052670
00155 Δ1199058284
0Δ1199053013
0 Δ1199058038
00055 Δ1199054355
0 Δ1199052870
0 Δ1199055485
0Δ1199055813
00262 Δ1199054139
0 Δ1199055055
0 Δ1199052970
0 Δ1199051086
0Δ1199052615
0 Δ1199058440
0 Δ1199055155
0 Δ1199053070
00003 Δ1199051186
00116Δ1199052715
0 Δ1199058341
0 Δ1199051056
00082 Δ1199055670
00368 Δ1199051286
02807Δ1199052815
0 Δ1199053842
01969 Δ1199051156
0 Δ1199055870
00215 Δ1199051386
00363Δ1199052915
0 Δ1199058642
0 Δ1199051256
02863 Δ1199052671
0 Δ1199055086
05105Δ1199053015
0 Δ1199053843
05089 Δ1199054356
00169 Δ1199052771
00031 Δ1199055186
0Δ1199055615
0 Δ1199058543
03278 Δ1199055056
05088 Δ1199052971
00142Δ1199051716
00001 Δ119905244
00333 Δ1199055156
00146 Δ1199053071
0006
shows relay number the second column (119879) shows relayoperating time for a fault close to the circuit breaker ofeach relay and the third column indicates the TMS of therelays From Table 8 all of the values of Δ119905mb are small andpositive numbers The positive values of Δ119905mb show that
there is no miscoordination in the results For example Δ11990541
refers to the relay pairs (4 and 1) that are obtained at 03529seconds The values of the five coefficients of the objectivefunction 120573 120572
1 1205722 119872 and 119873 are obtained as 5855 15 5
125 and 6 respectively When a fault occurs at downstream
ISRN Power Engineering 9
Table 9 Comparison between the proposed method and themethod of [11]
Case 1 Case 2 Case 3 Case 4120573 = 1 120573 = 10 120573 = 10 120573 = 58551205721= 1 120572
1= 10 120572
1= 1 120572
1= 15
1205722= 100 120572
2= 1 120572
2= 10 120572
2= 5
119872 = 2 119872 = 2 119872 = 2 119872 = 125N = 2 N = 2 N = 2 N = 6
sumΔ119905 298211 24115 269 2219sumTMS 1515 1455 156 1132
operating time of the downstreamprotective relays would notbe affected [21] In current grading the pickup current waschosen by considering the maximum possible load currentdue to normal overloading or contingency conditions Theloads of the buses 11 and 26 are the static types and thereis no need to install overcurrent relays on these buses SoTMSs of relays 57 and 79 that are connected to these buses areconsidered to be 005 [22] and other TMSs were calculated
In Table 9 the results of the simulations for the four casesare illustrated In this table the first row shows the fourdifferent cases and the second and the third rows show theresults of the first index (sumΔ119905) and the second index (sumTMS)for these cases The three first cases are related to the methodof [11] where in these cases the coefficients of the objectivefunction are set before optimization processThe values of thecoefficients are shown in the first column of the tableThe lastcase shows the results of the proposed method The values ofΔ119905 in all cases are positive and have not any miscoordination
The advantage of the proposed method is revealed whenthe results of the proposed method (Case 4) are comparedwith the best results of the traditional method of [11]According to Table 9 the best sumTMS and sumΔ119905 of method[11] (between three cases 1 and 2 and 3) are 1455 and24115 respectively whereassumTMS andsumΔt of the proposedmethod are 1132 and 2219 respectively This means thatthe results of Case 4 related to the new proposed methodshow the best coordination So considering the coefficientsof objective function as a part of the optimization prob-lem results are better compared with conventional methodaccording to the results of Tables 4 and 9
7 Conclusion
In this paper a new flexible technique for overcurrent relayscoordination has been proposed In this new technique thecoefficients of the conventional objective functions have beenimproved by optimization problem to obtain the minimumvalues for the TMSs of the relays In the proposed tech-nique GAPSOA optimization method is used to solve theoptimization problem This proposed method is tested on 6-bus case study and 30-bus IEEE case study The results ofthe simulation show the flexibility of the technique and thebest reliability because of the smallest sumTMS and sumΔ119905mbcompared to the conventional coordination methods
Conflict of Interests
The authors declare that there is no conflict of interestsregarding the publication of this paper
References
[1] R Mohammadi H A Abyaneh F Razavi M Al-Dabbaghand S H H Sadeghi ldquoOptimal relays coordination efficientmethod in interconnected power systemsrdquo Journal of ElectricalEngineering vol 61 no 2 pp 75ndash83 2010
[2] K Mazlumi and H A Abyaneh ldquoRelay coordination and pro-tection failure effects on reliability indices in an interconnectedsub-transmission systemrdquo Electric Power Systems Research vol79 no 7 pp 1011ndash1017 2009
[3] D Birla R P Maheshwari and H O Gupta ldquoTime overcurrentrelay coordination a reviewrdquo International Journal of EmergingElectric Power Systems vol 2 no 2 2005
[4] M Ojaghi Z Sudi and J Faiz ldquoImplementation of full adaptivetechnique to optimal coordination of overcurrent relaysrdquo IEEETransactions on Power Delivery vol 28 no 1 pp 235ndash244 2013
[5] C W So and K K Li ldquoOvercurrent relay coordination byevolutionary programmingrdquo Electric Power Systems Researchvol 53 no 2 pp 83ndash90 2000
[6] CW So K K Li K T Lai and K Y Fung ldquoApplication of gen-etic algorithm for overcurrent relay coordinationrdquo in Proceed-ings of the 6th International Conference on Developments inPower System Protection pp 66ndash69 1997
[7] C W So and K K Li ldquoTime coordination method for powersystem protection by evolutionary algorithmrdquo IEEE Transac-tions on Industry Applications vol 36 no 5 pp 1235ndash12402000
[8] J A Sueiro E Diaz-Dorado E Miguez and J Cidras ldquoCoordi-nation of directional overcurrent relay using evolutionary algo-rithm and linear programmingrdquo International Journal of Elec-trical Power amp Energy Systems vol 42 no 1 pp 299ndash305 2012
[9] M Ezzeddine and R Kaczmarek ldquoA novel method for optimalcoordination of directional overcurrent relays considering theiravailable discrete settings and several operation characteristicsrdquoElectric Power Systems Research vol 81 no 7 pp 1475ndash14812011
[10] P P Bedekar and S R Bhide ldquoOptimum coordination ofovercurrent relay timing using continuous genetic algorithmrdquoExpert Systems with Applications vol 38 no 9 pp 11286ndash112922011
[11] F Razavi H A Abyaneh M Al-Dabbagh R Mohammadiand H Torkaman ldquoA new comprehensive genetic algorithmmethod for optimal overcurrent relays coordinationrdquo ElectricPower Systems Research vol 78 no 4 pp 713ndash720 2008
[12] D E Goldberg Genetic Algorithms in Search Optimization andMachine Learning Addison-Wesley Reading Mass USA 1989
[13] D Adler ldquoGenetic algorithms and simulated annealing a mar-rage proposalrdquo in Proceedings of the IEEE International Confer-ence on Neural Networks vol 2 pp 1104ndash1109 1993
[14] K Premalatha and A M Natarajan ldquoHybrid PSO and GA forglobalmaximizationrdquo International Journal of Open Problems inComputer Science and Mathematics vol 2 no 4 2009
[15] H-J Lee G Son and J-W Park ldquoStudy on wind-turbine gen-erator system sizing considering voltage regulation and over-current relay coordinationrdquo IEEE Transactions on Power Sys-tems vol 26 no 3 pp 1283ndash1293 2011
10 ISRN Power Engineering
[16] T Amraee ldquoCoordination of directional overcurrent relaysusing seeker algorithmrdquo IEEE Transactions on Power Deliveryvol 27 no 3 pp 1415ndash1422 2012
[17] P P Bedekar and S R Bhide ldquoOptimum coordination of direc-tional overcurrent relays using the hybrid GA-NLP approachrdquoIEEE Transactions on Power Delivery vol 26 no 1 pp 109ndash1192011
[18] R M Chabanloo H A Abyaneh S S H Kamangar and FRazavi ldquoOptimal combined overcurrent and distance relayscoordination incorporating intelligent overcurrent relays char-acteristic selectionrdquo IEEE Transactions on Power Delivery vol26 no 3 pp 1381ndash1391 2011
[19] H Sharifian H A Abyaneh S K Salman R Mohammadiand F Razavi ldquoDetermination of the minimum break point setusing expert system and genetic algorithmrdquo IEEE Transactionson Power Delivery vol 25 no 3 pp 1284ndash1295 2010
[20] Power system test cases 1999 httpwwweewashingtoneduresearchpstcapf30ieee30cdftxt
[21] P G Slade J-L Wu E J Stacey et al ldquoThe utility requirementsfor a distribution fault current limiterrdquo IEEE Transactions onPower Delivery vol 7 no 2 pp 507ndash515 1992
[22] J R S S Kumara A Atputharajah J B Ekanayake and FJ Mumford ldquoOver current protection coordination of distri-bution networks with fault current limitersrdquo in Proceedings ofthe IEEE Power Engineering Society General Meeting (PES rsquo06)Montreal Canada 2006
International Journal of
AerospaceEngineeringHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
RoboticsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Active and Passive Electronic Components
Control Scienceand Engineering
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
International Journal of
RotatingMachinery
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporation httpwwwhindawicom
Journal ofEngineeringVolume 2014
Submit your manuscripts athttpwwwhindawicom
VLSI Design
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Shock and Vibration
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Civil EngineeringAdvances in
Acoustics and VibrationAdvances in
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Electrical and Computer Engineering
Journal of
Advances inOptoElectronics
Hindawi Publishing Corporation httpwwwhindawicom
Volume 2014
The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
SensorsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Modelling amp Simulation in EngineeringHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Chemical EngineeringInternational Journal of Antennas and
Propagation
International Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Navigation and Observation
International Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
DistributedSensor Networks
International Journal of
ISRN Power Engineering 7
Table 7 Coordination output results
Relay number 119879 TMS1 03092 01172 03092 01173 03467 01194 02095 00685 07561 01026 05671 02277 0248 00918 07271 01899 05679 010710 06679 024511 067 024112 0423 016013 0621 019514 09412 02515 09268 017016 02343 007417 05493 013918 05749 019019 03947 010520 05669 016321 02716 005922 05094 009023 05468 013924 07716 014225 07482 021726 06391 023927 06033 020328 06351 018429 06351 018430 06358 018331 04274 008832 05374 011833 0252 009034 02694 008935 03322 008436 08262 017437 04902 010638 01732 00539 01731 006140 01627 006841 06102 012342 02748 011543 0656 02544 02103 007645 02249 008446 0397 008147 01756 005648 05501 0179
Table 7 Continued
Relay number 119879 TMS49 07792 015550 01803 006151 0654 021152 06578 016653 06173 012954 05556 009355 10366 022456 05839 014358 06095 017659 02618 006560 04635 012961 02769 005662 03095 006163 03954 006664 05534 012865 03576 009466 05278 009967 05855 009968 07435 016169 05109 009570 06543 011371 02269 007872 0477 014373 02072 007074 06521 020475 03362 010476 05226 011577 02853 007378 04494 011680 04341 013781 03934 011182 08588 015483 09303 020284 05091 007785 03488 014486 03566 0079
In this paper four different cases are simulated for asuitable comparison Three cases are simulated according tothemethod of [11] in which the objective function coefficientsare set manually and the last case is simulated according tothe method proposed in this paper in which the objectivefunction coefficients are not set before simulation and theoptimization results show the values of the coefficients Allcases are evaluated by HGAPSO algorithm and all controlparameters of algorithm are listed in Table 6 The parametersare considered the same as 4 test cases A number of variablesin new method are considered 91 86 variables for relaysnumber and 5 variables for (120573 120572
1 1205722119872119873) and for method
proposed in [11] are considered 86Firstly the results of the proposed method by GAPSOA
are shown in Tables 7 and 8 The first column of Table 7
8 ISRN Power Engineering
Table 8 Time difference for each pair of MB relays
Δ11990541
03529 Δ1199051816
00021 Δ119905344
0 Δ1199051557
0 Δ1199055671
00122Δ11990561
0 Δ1199051916
01591 Δ119905145
00337 Δ1199055557
0 Δ1199055871
00025Δ11990571
03146 Δ1199052016
0 Δ119905345
0 Δ1199051458
01002 Δ1199052672
0Δ119905451
03418 Δ1199052118
10402 Δ119905146
0 Δ1199055558
0 Δ1199052772
0Δ11990542
03529 Δ1199052319
0 Δ119905246
0 Δ119905859
0 Δ1199052872
0Δ11990562
0 Δ1199053219
00027 Δ119905647
0 Δ1199054759
05927 Δ1199053072
0Δ11990572
03146 Δ1199056419
0 Δ119905747
03238 Δ1199054859
01788 Δ1199055672
0Δ119905442
03565 Δ1199052220
05459 Δ1199054447
03147 Δ1199051860
0 Δ1199055872
0Δ11990553
0 Δ1199052321
00023 Δ1199054547
03 Δ1199051960
01665 Δ1199052673
00003Δ11990584
0 Δ1199053221
0 Δ1199054648
0 Δ1199052060
00008 Δ1199052773
0Δ119905164
056 Δ1199056221
02384 Δ119905449
0 Δ1199055960
03069 Δ1199052873
0Δ119905484
01792 Δ1199057022
0 Δ119905749
0 Δ1199051761
0 Δ1199052973
0Δ11990585
0 Δ1199052423
03009 Δ1199054449
0 Δ1199051961
0 Δ1199055673
00081Δ119905165
05385 Δ1199052524
0 Δ1199054549
0 Δ1199052061
0 Δ1199055873
0Δ119905475
05848 Δ1199056925
0 Δ119905450
03518 Δ1199055961
0 Δ1199057174
02501Δ11990596
06558 Δ1199056826
04949 Δ119905650
0 Δ1199051762
0 Δ1199057274
0Δ119905107
0015 Δ1199056527
02957 Δ1199054450
03118 Δ1199051862
00312 Δ1199052375
00048Δ119905117
0 Δ1199053128
0 Δ1199054550
02971 Δ1199052062
00022 Δ1199056275
02319Δ119905127
02883 Δ1199057228
0 Δ1199051651
03311 Δ1199055962
03093 Δ1199056475
0Δ119905137
00488 Δ1199053129
0 Δ1199054751
03843 Δ1199051763
0 Δ1199057376
04701Δ119905437
00184 Δ1199057129
0 Δ1199054851
0 Δ1199051863
00059 Δ1199057476
0Δ119905517
00165 Δ1199053330
0 Δ1199054952
0 Δ1199051963
01605 Δ1199057577
0Δ119905108
00076 Δ1199057430
0 Δ1199051153
0 Δ1199055963
03125 Δ1199057678
0Δ119905118
0 Δ1199053331
0 Δ1199051253
02759 Δ1199056164
0 Δ1199057778
0Δ119905128
02671 Δ1199057331
00514 Δ1199051353
00489 Δ1199056365
0 Δ1199053779
0Δ119905138
00494 Δ1199053432
06332 Δ1199054353
00171 Δ1199053266
00072 Δ1199057879
02437Δ119905438
00161 Δ1199053533
0 Δ1199055053
05228 Δ1199056266
02319 Δ1199053680
0Δ119905508
05093 Δ1199057733
00416 Δ1199055153
00163 Δ1199056466
0 Δ1199057880
03633Δ119905539
0 Δ1199053534
02067 Δ1199051054
0 Δ1199056667
0 Δ1199058581
0Δ1199055210
00881 Δ1199057634
0 Δ1199051254
0 Δ1199056768
0 Δ1199058681
0Δ1199054211
03288 Δ1199053635
0 Δ1199051354
0 Δ1199052769
00239 Δ1199054082
0Δ1199051412
00006 Δ1199053735
02988 Δ1199054354
0 Δ1199052869
0 Δ1199058082
0Δ1199051512
0 Δ1199053937
02264 Δ1199055054
0 Δ1199052969
0 Δ1199058182
0Δ1199052613
0005 Δ1199054037
02523 Δ1199055154
0 Δ1199053069
00006 Δ1199053983
0Δ1199052713
0027 Δ1199058137
0 Δ1199051055
0 Δ1199055669
00331 Δ1199058083
0Δ1199052813
00001 Δ1199053938
03152 Δ1199051155
0 Δ1199055869
00202 Δ1199058183
0Δ1199052913
00001 Δ1199054038
03684 Δ1199051355
0 Δ1199052670
00155 Δ1199058284
0Δ1199053013
0 Δ1199058038
00055 Δ1199054355
0 Δ1199052870
0 Δ1199055485
0Δ1199055813
00262 Δ1199054139
0 Δ1199055055
0 Δ1199052970
0 Δ1199051086
0Δ1199052615
0 Δ1199058440
0 Δ1199055155
0 Δ1199053070
00003 Δ1199051186
00116Δ1199052715
0 Δ1199058341
0 Δ1199051056
00082 Δ1199055670
00368 Δ1199051286
02807Δ1199052815
0 Δ1199053842
01969 Δ1199051156
0 Δ1199055870
00215 Δ1199051386
00363Δ1199052915
0 Δ1199058642
0 Δ1199051256
02863 Δ1199052671
0 Δ1199055086
05105Δ1199053015
0 Δ1199053843
05089 Δ1199054356
00169 Δ1199052771
00031 Δ1199055186
0Δ1199055615
0 Δ1199058543
03278 Δ1199055056
05088 Δ1199052971
00142Δ1199051716
00001 Δ119905244
00333 Δ1199055156
00146 Δ1199053071
0006
shows relay number the second column (119879) shows relayoperating time for a fault close to the circuit breaker ofeach relay and the third column indicates the TMS of therelays From Table 8 all of the values of Δ119905mb are small andpositive numbers The positive values of Δ119905mb show that
there is no miscoordination in the results For example Δ11990541
refers to the relay pairs (4 and 1) that are obtained at 03529seconds The values of the five coefficients of the objectivefunction 120573 120572
1 1205722 119872 and 119873 are obtained as 5855 15 5
125 and 6 respectively When a fault occurs at downstream
ISRN Power Engineering 9
Table 9 Comparison between the proposed method and themethod of [11]
Case 1 Case 2 Case 3 Case 4120573 = 1 120573 = 10 120573 = 10 120573 = 58551205721= 1 120572
1= 10 120572
1= 1 120572
1= 15
1205722= 100 120572
2= 1 120572
2= 10 120572
2= 5
119872 = 2 119872 = 2 119872 = 2 119872 = 125N = 2 N = 2 N = 2 N = 6
sumΔ119905 298211 24115 269 2219sumTMS 1515 1455 156 1132
operating time of the downstreamprotective relays would notbe affected [21] In current grading the pickup current waschosen by considering the maximum possible load currentdue to normal overloading or contingency conditions Theloads of the buses 11 and 26 are the static types and thereis no need to install overcurrent relays on these buses SoTMSs of relays 57 and 79 that are connected to these buses areconsidered to be 005 [22] and other TMSs were calculated
In Table 9 the results of the simulations for the four casesare illustrated In this table the first row shows the fourdifferent cases and the second and the third rows show theresults of the first index (sumΔ119905) and the second index (sumTMS)for these cases The three first cases are related to the methodof [11] where in these cases the coefficients of the objectivefunction are set before optimization processThe values of thecoefficients are shown in the first column of the tableThe lastcase shows the results of the proposed method The values ofΔ119905 in all cases are positive and have not any miscoordination
The advantage of the proposed method is revealed whenthe results of the proposed method (Case 4) are comparedwith the best results of the traditional method of [11]According to Table 9 the best sumTMS and sumΔ119905 of method[11] (between three cases 1 and 2 and 3) are 1455 and24115 respectively whereassumTMS andsumΔt of the proposedmethod are 1132 and 2219 respectively This means thatthe results of Case 4 related to the new proposed methodshow the best coordination So considering the coefficientsof objective function as a part of the optimization prob-lem results are better compared with conventional methodaccording to the results of Tables 4 and 9
7 Conclusion
In this paper a new flexible technique for overcurrent relayscoordination has been proposed In this new technique thecoefficients of the conventional objective functions have beenimproved by optimization problem to obtain the minimumvalues for the TMSs of the relays In the proposed tech-nique GAPSOA optimization method is used to solve theoptimization problem This proposed method is tested on 6-bus case study and 30-bus IEEE case study The results ofthe simulation show the flexibility of the technique and thebest reliability because of the smallest sumTMS and sumΔ119905mbcompared to the conventional coordination methods
Conflict of Interests
The authors declare that there is no conflict of interestsregarding the publication of this paper
References
[1] R Mohammadi H A Abyaneh F Razavi M Al-Dabbaghand S H H Sadeghi ldquoOptimal relays coordination efficientmethod in interconnected power systemsrdquo Journal of ElectricalEngineering vol 61 no 2 pp 75ndash83 2010
[2] K Mazlumi and H A Abyaneh ldquoRelay coordination and pro-tection failure effects on reliability indices in an interconnectedsub-transmission systemrdquo Electric Power Systems Research vol79 no 7 pp 1011ndash1017 2009
[3] D Birla R P Maheshwari and H O Gupta ldquoTime overcurrentrelay coordination a reviewrdquo International Journal of EmergingElectric Power Systems vol 2 no 2 2005
[4] M Ojaghi Z Sudi and J Faiz ldquoImplementation of full adaptivetechnique to optimal coordination of overcurrent relaysrdquo IEEETransactions on Power Delivery vol 28 no 1 pp 235ndash244 2013
[5] C W So and K K Li ldquoOvercurrent relay coordination byevolutionary programmingrdquo Electric Power Systems Researchvol 53 no 2 pp 83ndash90 2000
[6] CW So K K Li K T Lai and K Y Fung ldquoApplication of gen-etic algorithm for overcurrent relay coordinationrdquo in Proceed-ings of the 6th International Conference on Developments inPower System Protection pp 66ndash69 1997
[7] C W So and K K Li ldquoTime coordination method for powersystem protection by evolutionary algorithmrdquo IEEE Transac-tions on Industry Applications vol 36 no 5 pp 1235ndash12402000
[8] J A Sueiro E Diaz-Dorado E Miguez and J Cidras ldquoCoordi-nation of directional overcurrent relay using evolutionary algo-rithm and linear programmingrdquo International Journal of Elec-trical Power amp Energy Systems vol 42 no 1 pp 299ndash305 2012
[9] M Ezzeddine and R Kaczmarek ldquoA novel method for optimalcoordination of directional overcurrent relays considering theiravailable discrete settings and several operation characteristicsrdquoElectric Power Systems Research vol 81 no 7 pp 1475ndash14812011
[10] P P Bedekar and S R Bhide ldquoOptimum coordination ofovercurrent relay timing using continuous genetic algorithmrdquoExpert Systems with Applications vol 38 no 9 pp 11286ndash112922011
[11] F Razavi H A Abyaneh M Al-Dabbagh R Mohammadiand H Torkaman ldquoA new comprehensive genetic algorithmmethod for optimal overcurrent relays coordinationrdquo ElectricPower Systems Research vol 78 no 4 pp 713ndash720 2008
[12] D E Goldberg Genetic Algorithms in Search Optimization andMachine Learning Addison-Wesley Reading Mass USA 1989
[13] D Adler ldquoGenetic algorithms and simulated annealing a mar-rage proposalrdquo in Proceedings of the IEEE International Confer-ence on Neural Networks vol 2 pp 1104ndash1109 1993
[14] K Premalatha and A M Natarajan ldquoHybrid PSO and GA forglobalmaximizationrdquo International Journal of Open Problems inComputer Science and Mathematics vol 2 no 4 2009
[15] H-J Lee G Son and J-W Park ldquoStudy on wind-turbine gen-erator system sizing considering voltage regulation and over-current relay coordinationrdquo IEEE Transactions on Power Sys-tems vol 26 no 3 pp 1283ndash1293 2011
10 ISRN Power Engineering
[16] T Amraee ldquoCoordination of directional overcurrent relaysusing seeker algorithmrdquo IEEE Transactions on Power Deliveryvol 27 no 3 pp 1415ndash1422 2012
[17] P P Bedekar and S R Bhide ldquoOptimum coordination of direc-tional overcurrent relays using the hybrid GA-NLP approachrdquoIEEE Transactions on Power Delivery vol 26 no 1 pp 109ndash1192011
[18] R M Chabanloo H A Abyaneh S S H Kamangar and FRazavi ldquoOptimal combined overcurrent and distance relayscoordination incorporating intelligent overcurrent relays char-acteristic selectionrdquo IEEE Transactions on Power Delivery vol26 no 3 pp 1381ndash1391 2011
[19] H Sharifian H A Abyaneh S K Salman R Mohammadiand F Razavi ldquoDetermination of the minimum break point setusing expert system and genetic algorithmrdquo IEEE Transactionson Power Delivery vol 25 no 3 pp 1284ndash1295 2010
[20] Power system test cases 1999 httpwwweewashingtoneduresearchpstcapf30ieee30cdftxt
[21] P G Slade J-L Wu E J Stacey et al ldquoThe utility requirementsfor a distribution fault current limiterrdquo IEEE Transactions onPower Delivery vol 7 no 2 pp 507ndash515 1992
[22] J R S S Kumara A Atputharajah J B Ekanayake and FJ Mumford ldquoOver current protection coordination of distri-bution networks with fault current limitersrdquo in Proceedings ofthe IEEE Power Engineering Society General Meeting (PES rsquo06)Montreal Canada 2006
International Journal of
AerospaceEngineeringHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
RoboticsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Active and Passive Electronic Components
Control Scienceand Engineering
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
International Journal of
RotatingMachinery
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporation httpwwwhindawicom
Journal ofEngineeringVolume 2014
Submit your manuscripts athttpwwwhindawicom
VLSI Design
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Shock and Vibration
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Civil EngineeringAdvances in
Acoustics and VibrationAdvances in
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Electrical and Computer Engineering
Journal of
Advances inOptoElectronics
Hindawi Publishing Corporation httpwwwhindawicom
Volume 2014
The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
SensorsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Modelling amp Simulation in EngineeringHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Chemical EngineeringInternational Journal of Antennas and
Propagation
International Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Navigation and Observation
International Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
DistributedSensor Networks
International Journal of
8 ISRN Power Engineering
Table 8 Time difference for each pair of MB relays
Δ11990541
03529 Δ1199051816
00021 Δ119905344
0 Δ1199051557
0 Δ1199055671
00122Δ11990561
0 Δ1199051916
01591 Δ119905145
00337 Δ1199055557
0 Δ1199055871
00025Δ11990571
03146 Δ1199052016
0 Δ119905345
0 Δ1199051458
01002 Δ1199052672
0Δ119905451
03418 Δ1199052118
10402 Δ119905146
0 Δ1199055558
0 Δ1199052772
0Δ11990542
03529 Δ1199052319
0 Δ119905246
0 Δ119905859
0 Δ1199052872
0Δ11990562
0 Δ1199053219
00027 Δ119905647
0 Δ1199054759
05927 Δ1199053072
0Δ11990572
03146 Δ1199056419
0 Δ119905747
03238 Δ1199054859
01788 Δ1199055672
0Δ119905442
03565 Δ1199052220
05459 Δ1199054447
03147 Δ1199051860
0 Δ1199055872
0Δ11990553
0 Δ1199052321
00023 Δ1199054547
03 Δ1199051960
01665 Δ1199052673
00003Δ11990584
0 Δ1199053221
0 Δ1199054648
0 Δ1199052060
00008 Δ1199052773
0Δ119905164
056 Δ1199056221
02384 Δ119905449
0 Δ1199055960
03069 Δ1199052873
0Δ119905484
01792 Δ1199057022
0 Δ119905749
0 Δ1199051761
0 Δ1199052973
0Δ11990585
0 Δ1199052423
03009 Δ1199054449
0 Δ1199051961
0 Δ1199055673
00081Δ119905165
05385 Δ1199052524
0 Δ1199054549
0 Δ1199052061
0 Δ1199055873
0Δ119905475
05848 Δ1199056925
0 Δ119905450
03518 Δ1199055961
0 Δ1199057174
02501Δ11990596
06558 Δ1199056826
04949 Δ119905650
0 Δ1199051762
0 Δ1199057274
0Δ119905107
0015 Δ1199056527
02957 Δ1199054450
03118 Δ1199051862
00312 Δ1199052375
00048Δ119905117
0 Δ1199053128
0 Δ1199054550
02971 Δ1199052062
00022 Δ1199056275
02319Δ119905127
02883 Δ1199057228
0 Δ1199051651
03311 Δ1199055962
03093 Δ1199056475
0Δ119905137
00488 Δ1199053129
0 Δ1199054751
03843 Δ1199051763
0 Δ1199057376
04701Δ119905437
00184 Δ1199057129
0 Δ1199054851
0 Δ1199051863
00059 Δ1199057476
0Δ119905517
00165 Δ1199053330
0 Δ1199054952
0 Δ1199051963
01605 Δ1199057577
0Δ119905108
00076 Δ1199057430
0 Δ1199051153
0 Δ1199055963
03125 Δ1199057678
0Δ119905118
0 Δ1199053331
0 Δ1199051253
02759 Δ1199056164
0 Δ1199057778
0Δ119905128
02671 Δ1199057331
00514 Δ1199051353
00489 Δ1199056365
0 Δ1199053779
0Δ119905138
00494 Δ1199053432
06332 Δ1199054353
00171 Δ1199053266
00072 Δ1199057879
02437Δ119905438
00161 Δ1199053533
0 Δ1199055053
05228 Δ1199056266
02319 Δ1199053680
0Δ119905508
05093 Δ1199057733
00416 Δ1199055153
00163 Δ1199056466
0 Δ1199057880
03633Δ119905539
0 Δ1199053534
02067 Δ1199051054
0 Δ1199056667
0 Δ1199058581
0Δ1199055210
00881 Δ1199057634
0 Δ1199051254
0 Δ1199056768
0 Δ1199058681
0Δ1199054211
03288 Δ1199053635
0 Δ1199051354
0 Δ1199052769
00239 Δ1199054082
0Δ1199051412
00006 Δ1199053735
02988 Δ1199054354
0 Δ1199052869
0 Δ1199058082
0Δ1199051512
0 Δ1199053937
02264 Δ1199055054
0 Δ1199052969
0 Δ1199058182
0Δ1199052613
0005 Δ1199054037
02523 Δ1199055154
0 Δ1199053069
00006 Δ1199053983
0Δ1199052713
0027 Δ1199058137
0 Δ1199051055
0 Δ1199055669
00331 Δ1199058083
0Δ1199052813
00001 Δ1199053938
03152 Δ1199051155
0 Δ1199055869
00202 Δ1199058183
0Δ1199052913
00001 Δ1199054038
03684 Δ1199051355
0 Δ1199052670
00155 Δ1199058284
0Δ1199053013
0 Δ1199058038
00055 Δ1199054355
0 Δ1199052870
0 Δ1199055485
0Δ1199055813
00262 Δ1199054139
0 Δ1199055055
0 Δ1199052970
0 Δ1199051086
0Δ1199052615
0 Δ1199058440
0 Δ1199055155
0 Δ1199053070
00003 Δ1199051186
00116Δ1199052715
0 Δ1199058341
0 Δ1199051056
00082 Δ1199055670
00368 Δ1199051286
02807Δ1199052815
0 Δ1199053842
01969 Δ1199051156
0 Δ1199055870
00215 Δ1199051386
00363Δ1199052915
0 Δ1199058642
0 Δ1199051256
02863 Δ1199052671
0 Δ1199055086
05105Δ1199053015
0 Δ1199053843
05089 Δ1199054356
00169 Δ1199052771
00031 Δ1199055186
0Δ1199055615
0 Δ1199058543
03278 Δ1199055056
05088 Δ1199052971
00142Δ1199051716
00001 Δ119905244
00333 Δ1199055156
00146 Δ1199053071
0006
shows relay number the second column (119879) shows relayoperating time for a fault close to the circuit breaker ofeach relay and the third column indicates the TMS of therelays From Table 8 all of the values of Δ119905mb are small andpositive numbers The positive values of Δ119905mb show that
there is no miscoordination in the results For example Δ11990541
refers to the relay pairs (4 and 1) that are obtained at 03529seconds The values of the five coefficients of the objectivefunction 120573 120572
1 1205722 119872 and 119873 are obtained as 5855 15 5
125 and 6 respectively When a fault occurs at downstream
ISRN Power Engineering 9
Table 9 Comparison between the proposed method and themethod of [11]
Case 1 Case 2 Case 3 Case 4120573 = 1 120573 = 10 120573 = 10 120573 = 58551205721= 1 120572
1= 10 120572
1= 1 120572
1= 15
1205722= 100 120572
2= 1 120572
2= 10 120572
2= 5
119872 = 2 119872 = 2 119872 = 2 119872 = 125N = 2 N = 2 N = 2 N = 6
sumΔ119905 298211 24115 269 2219sumTMS 1515 1455 156 1132
operating time of the downstreamprotective relays would notbe affected [21] In current grading the pickup current waschosen by considering the maximum possible load currentdue to normal overloading or contingency conditions Theloads of the buses 11 and 26 are the static types and thereis no need to install overcurrent relays on these buses SoTMSs of relays 57 and 79 that are connected to these buses areconsidered to be 005 [22] and other TMSs were calculated
In Table 9 the results of the simulations for the four casesare illustrated In this table the first row shows the fourdifferent cases and the second and the third rows show theresults of the first index (sumΔ119905) and the second index (sumTMS)for these cases The three first cases are related to the methodof [11] where in these cases the coefficients of the objectivefunction are set before optimization processThe values of thecoefficients are shown in the first column of the tableThe lastcase shows the results of the proposed method The values ofΔ119905 in all cases are positive and have not any miscoordination
The advantage of the proposed method is revealed whenthe results of the proposed method (Case 4) are comparedwith the best results of the traditional method of [11]According to Table 9 the best sumTMS and sumΔ119905 of method[11] (between three cases 1 and 2 and 3) are 1455 and24115 respectively whereassumTMS andsumΔt of the proposedmethod are 1132 and 2219 respectively This means thatthe results of Case 4 related to the new proposed methodshow the best coordination So considering the coefficientsof objective function as a part of the optimization prob-lem results are better compared with conventional methodaccording to the results of Tables 4 and 9
7 Conclusion
In this paper a new flexible technique for overcurrent relayscoordination has been proposed In this new technique thecoefficients of the conventional objective functions have beenimproved by optimization problem to obtain the minimumvalues for the TMSs of the relays In the proposed tech-nique GAPSOA optimization method is used to solve theoptimization problem This proposed method is tested on 6-bus case study and 30-bus IEEE case study The results ofthe simulation show the flexibility of the technique and thebest reliability because of the smallest sumTMS and sumΔ119905mbcompared to the conventional coordination methods
Conflict of Interests
The authors declare that there is no conflict of interestsregarding the publication of this paper
References
[1] R Mohammadi H A Abyaneh F Razavi M Al-Dabbaghand S H H Sadeghi ldquoOptimal relays coordination efficientmethod in interconnected power systemsrdquo Journal of ElectricalEngineering vol 61 no 2 pp 75ndash83 2010
[2] K Mazlumi and H A Abyaneh ldquoRelay coordination and pro-tection failure effects on reliability indices in an interconnectedsub-transmission systemrdquo Electric Power Systems Research vol79 no 7 pp 1011ndash1017 2009
[3] D Birla R P Maheshwari and H O Gupta ldquoTime overcurrentrelay coordination a reviewrdquo International Journal of EmergingElectric Power Systems vol 2 no 2 2005
[4] M Ojaghi Z Sudi and J Faiz ldquoImplementation of full adaptivetechnique to optimal coordination of overcurrent relaysrdquo IEEETransactions on Power Delivery vol 28 no 1 pp 235ndash244 2013
[5] C W So and K K Li ldquoOvercurrent relay coordination byevolutionary programmingrdquo Electric Power Systems Researchvol 53 no 2 pp 83ndash90 2000
[6] CW So K K Li K T Lai and K Y Fung ldquoApplication of gen-etic algorithm for overcurrent relay coordinationrdquo in Proceed-ings of the 6th International Conference on Developments inPower System Protection pp 66ndash69 1997
[7] C W So and K K Li ldquoTime coordination method for powersystem protection by evolutionary algorithmrdquo IEEE Transac-tions on Industry Applications vol 36 no 5 pp 1235ndash12402000
[8] J A Sueiro E Diaz-Dorado E Miguez and J Cidras ldquoCoordi-nation of directional overcurrent relay using evolutionary algo-rithm and linear programmingrdquo International Journal of Elec-trical Power amp Energy Systems vol 42 no 1 pp 299ndash305 2012
[9] M Ezzeddine and R Kaczmarek ldquoA novel method for optimalcoordination of directional overcurrent relays considering theiravailable discrete settings and several operation characteristicsrdquoElectric Power Systems Research vol 81 no 7 pp 1475ndash14812011
[10] P P Bedekar and S R Bhide ldquoOptimum coordination ofovercurrent relay timing using continuous genetic algorithmrdquoExpert Systems with Applications vol 38 no 9 pp 11286ndash112922011
[11] F Razavi H A Abyaneh M Al-Dabbagh R Mohammadiand H Torkaman ldquoA new comprehensive genetic algorithmmethod for optimal overcurrent relays coordinationrdquo ElectricPower Systems Research vol 78 no 4 pp 713ndash720 2008
[12] D E Goldberg Genetic Algorithms in Search Optimization andMachine Learning Addison-Wesley Reading Mass USA 1989
[13] D Adler ldquoGenetic algorithms and simulated annealing a mar-rage proposalrdquo in Proceedings of the IEEE International Confer-ence on Neural Networks vol 2 pp 1104ndash1109 1993
[14] K Premalatha and A M Natarajan ldquoHybrid PSO and GA forglobalmaximizationrdquo International Journal of Open Problems inComputer Science and Mathematics vol 2 no 4 2009
[15] H-J Lee G Son and J-W Park ldquoStudy on wind-turbine gen-erator system sizing considering voltage regulation and over-current relay coordinationrdquo IEEE Transactions on Power Sys-tems vol 26 no 3 pp 1283ndash1293 2011
10 ISRN Power Engineering
[16] T Amraee ldquoCoordination of directional overcurrent relaysusing seeker algorithmrdquo IEEE Transactions on Power Deliveryvol 27 no 3 pp 1415ndash1422 2012
[17] P P Bedekar and S R Bhide ldquoOptimum coordination of direc-tional overcurrent relays using the hybrid GA-NLP approachrdquoIEEE Transactions on Power Delivery vol 26 no 1 pp 109ndash1192011
[18] R M Chabanloo H A Abyaneh S S H Kamangar and FRazavi ldquoOptimal combined overcurrent and distance relayscoordination incorporating intelligent overcurrent relays char-acteristic selectionrdquo IEEE Transactions on Power Delivery vol26 no 3 pp 1381ndash1391 2011
[19] H Sharifian H A Abyaneh S K Salman R Mohammadiand F Razavi ldquoDetermination of the minimum break point setusing expert system and genetic algorithmrdquo IEEE Transactionson Power Delivery vol 25 no 3 pp 1284ndash1295 2010
[20] Power system test cases 1999 httpwwweewashingtoneduresearchpstcapf30ieee30cdftxt
[21] P G Slade J-L Wu E J Stacey et al ldquoThe utility requirementsfor a distribution fault current limiterrdquo IEEE Transactions onPower Delivery vol 7 no 2 pp 507ndash515 1992
[22] J R S S Kumara A Atputharajah J B Ekanayake and FJ Mumford ldquoOver current protection coordination of distri-bution networks with fault current limitersrdquo in Proceedings ofthe IEEE Power Engineering Society General Meeting (PES rsquo06)Montreal Canada 2006
International Journal of
AerospaceEngineeringHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
RoboticsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Active and Passive Electronic Components
Control Scienceand Engineering
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
International Journal of
RotatingMachinery
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporation httpwwwhindawicom
Journal ofEngineeringVolume 2014
Submit your manuscripts athttpwwwhindawicom
VLSI Design
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Shock and Vibration
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Civil EngineeringAdvances in
Acoustics and VibrationAdvances in
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Electrical and Computer Engineering
Journal of
Advances inOptoElectronics
Hindawi Publishing Corporation httpwwwhindawicom
Volume 2014
The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
SensorsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Modelling amp Simulation in EngineeringHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Chemical EngineeringInternational Journal of Antennas and
Propagation
International Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Navigation and Observation
International Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
DistributedSensor Networks
International Journal of
ISRN Power Engineering 9
Table 9 Comparison between the proposed method and themethod of [11]
Case 1 Case 2 Case 3 Case 4120573 = 1 120573 = 10 120573 = 10 120573 = 58551205721= 1 120572
1= 10 120572
1= 1 120572
1= 15
1205722= 100 120572
2= 1 120572
2= 10 120572
2= 5
119872 = 2 119872 = 2 119872 = 2 119872 = 125N = 2 N = 2 N = 2 N = 6
sumΔ119905 298211 24115 269 2219sumTMS 1515 1455 156 1132
operating time of the downstreamprotective relays would notbe affected [21] In current grading the pickup current waschosen by considering the maximum possible load currentdue to normal overloading or contingency conditions Theloads of the buses 11 and 26 are the static types and thereis no need to install overcurrent relays on these buses SoTMSs of relays 57 and 79 that are connected to these buses areconsidered to be 005 [22] and other TMSs were calculated
In Table 9 the results of the simulations for the four casesare illustrated In this table the first row shows the fourdifferent cases and the second and the third rows show theresults of the first index (sumΔ119905) and the second index (sumTMS)for these cases The three first cases are related to the methodof [11] where in these cases the coefficients of the objectivefunction are set before optimization processThe values of thecoefficients are shown in the first column of the tableThe lastcase shows the results of the proposed method The values ofΔ119905 in all cases are positive and have not any miscoordination
The advantage of the proposed method is revealed whenthe results of the proposed method (Case 4) are comparedwith the best results of the traditional method of [11]According to Table 9 the best sumTMS and sumΔ119905 of method[11] (between three cases 1 and 2 and 3) are 1455 and24115 respectively whereassumTMS andsumΔt of the proposedmethod are 1132 and 2219 respectively This means thatthe results of Case 4 related to the new proposed methodshow the best coordination So considering the coefficientsof objective function as a part of the optimization prob-lem results are better compared with conventional methodaccording to the results of Tables 4 and 9
7 Conclusion
In this paper a new flexible technique for overcurrent relayscoordination has been proposed In this new technique thecoefficients of the conventional objective functions have beenimproved by optimization problem to obtain the minimumvalues for the TMSs of the relays In the proposed tech-nique GAPSOA optimization method is used to solve theoptimization problem This proposed method is tested on 6-bus case study and 30-bus IEEE case study The results ofthe simulation show the flexibility of the technique and thebest reliability because of the smallest sumTMS and sumΔ119905mbcompared to the conventional coordination methods
Conflict of Interests
The authors declare that there is no conflict of interestsregarding the publication of this paper
References
[1] R Mohammadi H A Abyaneh F Razavi M Al-Dabbaghand S H H Sadeghi ldquoOptimal relays coordination efficientmethod in interconnected power systemsrdquo Journal of ElectricalEngineering vol 61 no 2 pp 75ndash83 2010
[2] K Mazlumi and H A Abyaneh ldquoRelay coordination and pro-tection failure effects on reliability indices in an interconnectedsub-transmission systemrdquo Electric Power Systems Research vol79 no 7 pp 1011ndash1017 2009
[3] D Birla R P Maheshwari and H O Gupta ldquoTime overcurrentrelay coordination a reviewrdquo International Journal of EmergingElectric Power Systems vol 2 no 2 2005
[4] M Ojaghi Z Sudi and J Faiz ldquoImplementation of full adaptivetechnique to optimal coordination of overcurrent relaysrdquo IEEETransactions on Power Delivery vol 28 no 1 pp 235ndash244 2013
[5] C W So and K K Li ldquoOvercurrent relay coordination byevolutionary programmingrdquo Electric Power Systems Researchvol 53 no 2 pp 83ndash90 2000
[6] CW So K K Li K T Lai and K Y Fung ldquoApplication of gen-etic algorithm for overcurrent relay coordinationrdquo in Proceed-ings of the 6th International Conference on Developments inPower System Protection pp 66ndash69 1997
[7] C W So and K K Li ldquoTime coordination method for powersystem protection by evolutionary algorithmrdquo IEEE Transac-tions on Industry Applications vol 36 no 5 pp 1235ndash12402000
[8] J A Sueiro E Diaz-Dorado E Miguez and J Cidras ldquoCoordi-nation of directional overcurrent relay using evolutionary algo-rithm and linear programmingrdquo International Journal of Elec-trical Power amp Energy Systems vol 42 no 1 pp 299ndash305 2012
[9] M Ezzeddine and R Kaczmarek ldquoA novel method for optimalcoordination of directional overcurrent relays considering theiravailable discrete settings and several operation characteristicsrdquoElectric Power Systems Research vol 81 no 7 pp 1475ndash14812011
[10] P P Bedekar and S R Bhide ldquoOptimum coordination ofovercurrent relay timing using continuous genetic algorithmrdquoExpert Systems with Applications vol 38 no 9 pp 11286ndash112922011
[11] F Razavi H A Abyaneh M Al-Dabbagh R Mohammadiand H Torkaman ldquoA new comprehensive genetic algorithmmethod for optimal overcurrent relays coordinationrdquo ElectricPower Systems Research vol 78 no 4 pp 713ndash720 2008
[12] D E Goldberg Genetic Algorithms in Search Optimization andMachine Learning Addison-Wesley Reading Mass USA 1989
[13] D Adler ldquoGenetic algorithms and simulated annealing a mar-rage proposalrdquo in Proceedings of the IEEE International Confer-ence on Neural Networks vol 2 pp 1104ndash1109 1993
[14] K Premalatha and A M Natarajan ldquoHybrid PSO and GA forglobalmaximizationrdquo International Journal of Open Problems inComputer Science and Mathematics vol 2 no 4 2009
[15] H-J Lee G Son and J-W Park ldquoStudy on wind-turbine gen-erator system sizing considering voltage regulation and over-current relay coordinationrdquo IEEE Transactions on Power Sys-tems vol 26 no 3 pp 1283ndash1293 2011
10 ISRN Power Engineering
[16] T Amraee ldquoCoordination of directional overcurrent relaysusing seeker algorithmrdquo IEEE Transactions on Power Deliveryvol 27 no 3 pp 1415ndash1422 2012
[17] P P Bedekar and S R Bhide ldquoOptimum coordination of direc-tional overcurrent relays using the hybrid GA-NLP approachrdquoIEEE Transactions on Power Delivery vol 26 no 1 pp 109ndash1192011
[18] R M Chabanloo H A Abyaneh S S H Kamangar and FRazavi ldquoOptimal combined overcurrent and distance relayscoordination incorporating intelligent overcurrent relays char-acteristic selectionrdquo IEEE Transactions on Power Delivery vol26 no 3 pp 1381ndash1391 2011
[19] H Sharifian H A Abyaneh S K Salman R Mohammadiand F Razavi ldquoDetermination of the minimum break point setusing expert system and genetic algorithmrdquo IEEE Transactionson Power Delivery vol 25 no 3 pp 1284ndash1295 2010
[20] Power system test cases 1999 httpwwweewashingtoneduresearchpstcapf30ieee30cdftxt
[21] P G Slade J-L Wu E J Stacey et al ldquoThe utility requirementsfor a distribution fault current limiterrdquo IEEE Transactions onPower Delivery vol 7 no 2 pp 507ndash515 1992
[22] J R S S Kumara A Atputharajah J B Ekanayake and FJ Mumford ldquoOver current protection coordination of distri-bution networks with fault current limitersrdquo in Proceedings ofthe IEEE Power Engineering Society General Meeting (PES rsquo06)Montreal Canada 2006
International Journal of
AerospaceEngineeringHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
RoboticsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Active and Passive Electronic Components
Control Scienceand Engineering
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
International Journal of
RotatingMachinery
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporation httpwwwhindawicom
Journal ofEngineeringVolume 2014
Submit your manuscripts athttpwwwhindawicom
VLSI Design
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Shock and Vibration
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Civil EngineeringAdvances in
Acoustics and VibrationAdvances in
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Electrical and Computer Engineering
Journal of
Advances inOptoElectronics
Hindawi Publishing Corporation httpwwwhindawicom
Volume 2014
The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
SensorsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Modelling amp Simulation in EngineeringHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Chemical EngineeringInternational Journal of Antennas and
Propagation
International Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Navigation and Observation
International Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
DistributedSensor Networks
International Journal of
10 ISRN Power Engineering
[16] T Amraee ldquoCoordination of directional overcurrent relaysusing seeker algorithmrdquo IEEE Transactions on Power Deliveryvol 27 no 3 pp 1415ndash1422 2012
[17] P P Bedekar and S R Bhide ldquoOptimum coordination of direc-tional overcurrent relays using the hybrid GA-NLP approachrdquoIEEE Transactions on Power Delivery vol 26 no 1 pp 109ndash1192011
[18] R M Chabanloo H A Abyaneh S S H Kamangar and FRazavi ldquoOptimal combined overcurrent and distance relayscoordination incorporating intelligent overcurrent relays char-acteristic selectionrdquo IEEE Transactions on Power Delivery vol26 no 3 pp 1381ndash1391 2011
[19] H Sharifian H A Abyaneh S K Salman R Mohammadiand F Razavi ldquoDetermination of the minimum break point setusing expert system and genetic algorithmrdquo IEEE Transactionson Power Delivery vol 25 no 3 pp 1284ndash1295 2010
[20] Power system test cases 1999 httpwwweewashingtoneduresearchpstcapf30ieee30cdftxt
[21] P G Slade J-L Wu E J Stacey et al ldquoThe utility requirementsfor a distribution fault current limiterrdquo IEEE Transactions onPower Delivery vol 7 no 2 pp 507ndash515 1992
[22] J R S S Kumara A Atputharajah J B Ekanayake and FJ Mumford ldquoOver current protection coordination of distri-bution networks with fault current limitersrdquo in Proceedings ofthe IEEE Power Engineering Society General Meeting (PES rsquo06)Montreal Canada 2006
International Journal of
AerospaceEngineeringHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
RoboticsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Active and Passive Electronic Components
Control Scienceand Engineering
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
International Journal of
RotatingMachinery
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporation httpwwwhindawicom
Journal ofEngineeringVolume 2014
Submit your manuscripts athttpwwwhindawicom
VLSI Design
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Shock and Vibration
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Civil EngineeringAdvances in
Acoustics and VibrationAdvances in
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Electrical and Computer Engineering
Journal of
Advances inOptoElectronics
Hindawi Publishing Corporation httpwwwhindawicom
Volume 2014
The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
SensorsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Modelling amp Simulation in EngineeringHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Chemical EngineeringInternational Journal of Antennas and
Propagation
International Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Navigation and Observation
International Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
DistributedSensor Networks
International Journal of
International Journal of
AerospaceEngineeringHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
RoboticsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Active and Passive Electronic Components
Control Scienceand Engineering
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
International Journal of
RotatingMachinery
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporation httpwwwhindawicom
Journal ofEngineeringVolume 2014
Submit your manuscripts athttpwwwhindawicom
VLSI Design
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Shock and Vibration
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Civil EngineeringAdvances in
Acoustics and VibrationAdvances in
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Electrical and Computer Engineering
Journal of
Advances inOptoElectronics
Hindawi Publishing Corporation httpwwwhindawicom
Volume 2014
The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
SensorsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Modelling amp Simulation in EngineeringHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Chemical EngineeringInternational Journal of Antennas and
Propagation
International Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Navigation and Observation
International Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
DistributedSensor Networks
International Journal of