power quality improvement using shunt active …...power quality improvement using shunt active...

International Journal of Engineering, Management & Sciences (IJEMS)ISSN-2348 –3733, Volume-2, Issue-1, January 2015

9 www.alliedjournals.com

Abstract— Power quality is a very important issue.

Non-linear loads and semi-conductor devices connected to ACelectric mains generate unwanted signals (harmonics) in thedynamics of current which are responsible for additional powerlosses in heat loss and the risk of equipment damage ormalfunctioning.

In the simulink model of shunt active filter fuzzy logiccontroller and hysteresis current controller for reducing theharmonic distortion. Powergui tool of mat lab provides thefunction of FFT analysis which is very important to calculatetotal harmonic distortion in source current. By taking variousfiring angles the total harmonic distortion is calculated by FFTanalysis.

Index Terms—Shunt Active Filter, Fuzzy Logics, FFTanalysis, Harmonic Distortion

I. POWER QUALITY IN POWER SYSTEMSPower quality is a phrase that means different things to

different consumers. Power quality is defined in Institute ofElectrical and Electronic Engineers (IEEE) StandardIEEE1100 as “This is the method of power supply andgrounding sensitive electronic equipment and other nonlinearequipment in amanner such that is suitable for theequipment.” As appropriate as this description mightseem,the limitation of power quality to “sensitive electronicequipment and nonlinear equipment” might be subjecttodisagreement. Electrical equipment susceptible to powerquality or more suitableto lack of power quality would fallwithin a seemingly boundless domain.All electrical devicesare prone to failure or malfunction when exposed to oneormore than one power quality problems.

Examples of poor power quality

A. VOLTAGE SAG

Voltage sag (also called a “dip”) is a slight decrease in ther.m.s value of line voltage of 10 to 90 percent of the nominalline-voltage. The duration of a sag is 0.5 cycle to 1 minute[1.44–1.50].

B. Voltage swell

A voltage swell is the converse to the sag. A swell is abrief increase in the r.m.s of line-voltage of 110 to 180percent of the nominal line-voltage for duration of 0.5

Manuscript received January 18, 2015Kamalesh sharma, M.tech Scholar Apex Institute of Engineering

College JaipurSunil kumar goyal, Assistant Professor ,Manipal University, JaipurNagendra kumar swarnkar, 3Associate Professor at Apex Institute ofEngineering College, Jaipur

cycles to 1 minute. Sources of voltage swells are linefaults and incorrect tap settings in tap changers insubstations.

C. Transient

It is a brief, unidirectional variation in voltage and current, orboth on a power line. The Most Common The most commoncauses of impulsive transients are lightning strikes on powerline, switch on or off of inductive loads, or switching in thepower distribution system.

Interruption:Interruption is the reduction in line-voltage orline-current to less than 10% of the nominal, notexceeding 60 seconds in length.

Voltage Imbalance:A voltage “imbalance” is defined as variation in theamplitudes of 3-phase voltages, relative to another.

Flicker:Voltage fluctuations variations in the rmsline-voltage are relatively small (less than 5 percent).

II. POWER QUALITY INDICES UNDERHARMONIC DISTORTION

There are some power quality indices those arecomprehensibly described:

Total Harmonic Distortion:Total harmonic distortion (THD) is very importantindex. Which is widely used to describe power qualityagenda in transmission and distribution networks. Itconsiders the contribution of every individual harmoniccomponent on the signal. THD is given for voltage andcurrent signals, respectively, as given below:

(3.1)

Telephone Influence Factor (TIF):This index is found in IEEE-5197 as a measure of audiocircuit interference produced in electric power systemsby harmonics. It will thus use the total harmonicdistortion concept influenced by appropriate weightingfactors, ωh, that establish the sensitivity of the humanear to noise from different frequencies:

Power Quality Improvement Using Shunt ActiveFilterWith Fuzzy Logics

Kamalesh sharma, Sunil kumar goyal, Nagendra kumar swarnkar

Power Quality Improvement Using Shunt Active FilterWith Fuzzy Logics


(3.4)

Displacement, Distortion and Total PowerFactor

With an increasing harmonic distortion environment, theconventional definition of power factor is that thecosine of the angle between fundamental frequencyvoltage and current has progressed to consider rmsvalues the signal’s, which make up the contribution ofelectrical components of various frequencies. Thus,displacement power factor (DPF) continues tocharacterize the power frequency factor

III. SOURCES OF HARMONICSThe ac power system harmonic problems are mainly

occur due to the substantial increase of non-linear loads due totechnological upgrades, such as the use of power electronicscircuits, devices and semiconductor, in ac/dc transmissionlinks, or loads in the control of power systems using powerelectronic or microprocessor controllers. sources ofharmonics are divided into given loads:

(a) Domestic loads.(b) Industrial loads.(c) Control devices.

Fig. 4.1. Source Harmonics

IV. SOLUTION OF HARMONIC DISTORTIONIn general, used the filters for the harmonic

distortion likes, harmonic filter as a passive and active filters.A. ACTIVE FILTERSActive power filters have being developed since beginning

of power system, when one of the first prototypes based oninstantaneous power theory was reported. The technology ofactive power filter has been developed during the past two orthree decades reaching full growth for harmonicscompensation, reactive power and voltage balance in acpower system. All active power filters are developed with

PWM converters (CSI orVSI). The different active powerfilter methods are shown in Fig 5

(a)

(b)Active power filter topologies implemented withPWMVSI.(a) Shunt active power filter.(b) Series activepower filter.

B. FUZZY LOGICFuzzy logic control is determined from fuzzy set theory in1965; where transition is between membership andnon-membership function. Therefore, limitation orboundaries of fuzzy sets can be undefined and ambiguous;FLC’s are an excellent choice when precise mathematicalformula calculations are not possible. Fig. 6.1.given belowshows block diagram of the fuzzy logic control scheme.

Block diagram of fuzzy logic controller

SIMULINK MODEL FOR THE NON-LINEAR LOADSYSTEM WITH SHUNT ACTIVE FILTER

Modelling for non-linear load with shunt active filter

shows the modeling for shunt active filter with non-linearload,fuzzy logic based for the power quality improvementfrom harmonic distortion. Whenever circuit breaker is closedthe filter is connected with the system of non linear load.



V. RESULTS

A. WITHOUT SHUNT ACTIVE FILTER

Waveforms of voltages and currents without shunt activefilter

Harmonic Distortion in Source Current

Waveform of source current for firing angle 15○

THD in source current for firing angle 15○




THD in source current for firing angle 45 ○

B. WITH SHUNT ACTIVE FILTER

Waveforms of source voltages and currents with shuntactive filter

Power Quality Improvement Using Shunt Active FilterWith Fuzzy Logics


Harmonic Distortion in Source Current


THD in source current for firing angle 15 ○



Values for total harmonic distortion can be summarised fordifferent firing angles as follows:

TABLE 8.1THD% FOR THE DIFFERENT FIRING ANGLES

CONCLUSIONThis paper has described and illustrated that when

the shunt active filter is connected with the system ofnon-linear load, current and voltage can be preventedeffectively from harmonic distortion. Therefore simulinkmodel of the shunt active filter is very useful for getting thenewer controlled strategy or advanced techniques for thefiltering of non-linear load.

In addition to this powergui FFT analysis provideseffective percentage values of total harmonic distortion fordifferent firing angles provided with the system of non linearload which provides prediction of harmonic distortion incurrent according to the specifications of the system.

FUTURE SCOPEIn place of shunt active filter simulink model can be

designed by using series active filter to eliminate voltageharmonics and to balance and regulate the terminal voltage ofload or line. Hybrid configuration can also be used for thecompensation of high power systems.

Fuzzy logic controller has been used with hysteresis currentcontroller and PLL synchronisation in simulink model, whichcan be replaced by neural network controller. In the simulinkmodel of shunt active filter

REFERENCES

[1] JoãoAfonso, MaurícioAredes, Edson Watanabe &Júlio Martins,University of Minho - Industrial Electronics Dept., “Shunt Active Filter forPower Quality Improvement,” International Conference UIE 2000 –Electricity for a Sustainable Urban Development Lisboa, Portugal, pp.683-691, 1-4 November 2000.

[2] Bhim Singh, Kamal Al-Haddad &Ambrish Chandra, “A New ControlApproach to 3-phase Active Filter for Harmonics and Reactive PowerCompensation” -IEEE Trans. on Power Systems, Vol. 46, No. 5, pp. 133–138, Oct-1999.

Sr.No.

Firingangle indegree

THD%(Beforefiltering)

THD%(Afterfiltering)

1 15 27.86 5.292 30 31.75 5.74

3 45 36.11 5.87



[3] Karuppanan P &KamalakantaMahapatra Dept. Of National Instituteof Technology Rourkela, India-769008, “Fuzzy Logic Controlled ActivePower Line Conditioners for Power Quality Improvements,” InternationalConference on Advance in Energy Conversion Technologies (ICAECT2010), pp. 177-181, Jan 07-10-2010.

[4] B.Suresh Kumar, K.Ramesh Reddy &V.Lalitha, “PI, Fuzzy LogicControlled Shunt Active Power Filter for Three-Phase Four-Wire Systemswith Balanced, Unbalanced and Variable Loads,” Journal of Theoretical andApplied Information Technology, pp. 122-130, 2005-2011.

[5] Joao L. Fonso, Member IEEE, H.J Ribeiro De Silva & Julio S.Martins,Member IEEE “Active Filter For Power Quality Improvement.” IEEE PortoPower Tech Porto, Portugal, (ISBN: 0 7803 7139 9), 10-13 Sept. 2001.

[6] SoumiaKerrouche&FatehKrim, “Three-Phase Active Power FilterBased On Fuzzy Logic Controller” International Journal of Sciences andTechniques of Automatic Control & Computer Engineering, IJ-STA,Volume 3, N◦1, pp. 942-955, 1, July 2009.

[7] G.Jaykrishn& K.S.R. Anjaneyulu, “Fuzzy logic control based threephase shunt active filter for voltage regulation and harmonicsreduction,”International Journal of Computer Applications (0975 – 8887),Volume 10– No.5, pp. 13-19, November 2010.[8] D C Bhonsle, N K Zaveri&Dr R B Kelkar, “Design and Simulation ofSingle Phase Shunt Active Power Filter for Harmonic Mitigation inDistribution System”, The International Conference on ElectricalEngineering, pp.1-8, 6, July 2008.[9]J. L. Afonso, C. Couto, J. S. Martins, “Active Filters with Control Basedon the p-q Theory”, IEEE Industrial Electronics Society Newsletter, vol. 47,No. 3, pp. 5-10, Sept. 2000.

[10] Adrian GLIGOR, “Design and Simulation of a Shunt Active Filter inApplication for Control of Harmonic Levels” ActaUniversitatisSapientiaeElectrical and Mechanical Engineering, pp.53-63, Jan. 2009.

[11] S. Saad& L. Zellouma, “Fuzzy Logic Controller for Three-Level ShuntActive Filter Compensating Harmonics and Reactive Power”, Electric PowerSystems Research 79, pp. 1337-1341, May. 2009.

[12] AbdelmadjidChaoui, Jean-Paul Gaubert&FatehKrim, “Power QualityImprovement Using DPC Controlled Three-Phase Shunt Active Filter”,Electric Power Systems Research 80, pp. 657-666, Jan. 2010.

[13] Salem Rahmania, Kamal Al-Haddad &Hadi Youssef Kanaan, “AComparative Study of Shunt Hybrid and Shunt Active Power Filtersfor Single-Phase Applications: Simulation and Experimental Validation”,Mathematics and Computers in Simulation 71, pp. 345–359, May 2006.

power quality improvement using shunt active …...power quality improvement using shunt active...

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