ffiDURGAPUR PROJECT LIMITED

(A GOVERNMENT OF WEST BENGAL TJNDERTAKING)

SUMMER TRAINING REPORT

DURATIQN: 21106/2010 TO 20/0712010

SI]BMITTED BY.

U.ROLL

STREAM

SEM

ID

SANJIV SHOME.

07 1230116020

ELECTRICAL ENGG.

.THo.

EE/07 /37

DEPARTMENT OF ELECTRICAL ENGINEERING.

JIS COLLEGE OF ENGINEERING,KALYANI.

,!

ACKNOWLEDGEMENT

THIS IS A REPORT ON THE VOCATIONAL TRAINING ON DURGAPUR PROJECTSLIMITED. DURING THIS REPORT ICANNOT HARDLY FORGET MR. ANUP GHOSAT{ASSISTANT MANAGER OF TRAINING DEPT. DPL) , MR. A.K BHATTACHARYA AND IAM GREATFUL TO THEM FOR PERMITTING ME UNDERTAKE TRAINING IN HISREPUTED CONCERN FOR A PERIOD OF 4 WEEKS. I ALSO PAY MY GRATITUDE TOTHE HEADS AND EMPLOYEES OF ALL DEPATMENTS FOR GIVING THEIR VALUABLETIME AND CORPORATION WHICH HELPED A LOT IN CLARIFYING OUR DOUBTS.

3'o year Electr ical EngineeringJIS COLLEGE OF ENGINEERING, KALYANI.

In this modern world the dependence of electricity is so much that it

has become a part of life. There has been ever increasing use of electric

power for domestic, commercial and industrial purposes. This is

achieved with the help of suitable power producing units, known ds

power plant or electric power generating station. The design of power

plant should incorporate two important aspects.

Firstly the selection and placing of necessary power generating

equipment should be such so that a maximum return wi l l result f rom a

minimum of expenditure over working of life of plant. Secondly the

operation of the plant should be such to provide cheap reliable and

continuous service.

"DURGAPUR PROJECT LIMITED" was established in the year 1950. lt has

one power plant, water works and coke oven plant. Our interest is

regarding the power plant. lt has 6 running units of total 671 MW

(300+30+77 +7 7 +7 7 +L10=67 1 ) ge nerati on ca pacities.

DPL OVERVIEW

Formation:The Durgapur Project Limited is a govemrnent organization incorporated on 6thSeptember, I 96 Iconsisting of coke oven batteries, by-product plant, gas-gnd projec! thermal power plantandwater works . It is under the administrative control of the department of Power, Govt. ofw.B.

Location:The organization -plants and administrative offices are located within 3 km. fromDdrgapurRailway Station and 1 km from G.T. Road.

Business:The Durgapur Projects Limited is the first under taking ofthe State govt. which has beenengaged in development of infrastructure for industries and was given t}te stature ofan"Industryfor Induskies". It has helped in development ofvarious large, medium and small scaleindustriesin and around Durgapur and other places within the state.

Activities:1. Gederation of Power and its distribution at l1 kV in its licensed area in Durgapur andtransmission of supply power to WBSEB.2. Production of metallurgical coke of Blast fumace, foundries, etc., coke oven gas asindustrial fuel and crude coal tar available from its recovery types of coke oven batteries.3. Treatment ant and distribution of water for drinking and industrial use.

Infrastructure:Land - l9l0 acres comprising of 1060 acres for plant and 850 acres for township.Railway Network - Separate railway exchange yard, @COP siding) with railwaymaintainedWieghbridge facility.

o)

Power plant3The organization is generaling power from its seven power units with an aggregatecapacity of701 M.W.and distributing to its consumers at various categories located in its comrnandareas atDurgapur and the received power is transmitted tbrough the West Bengal State ElectricityBoardGrid. The company ensuressteady and unintemrpted supply ofpower to its consumers.

More facts:Durgapur Projects Limited's total power generation capacity after the recent renovationand upgradation, today stands at 401 megawatt (MW). It is qngaged in all the threefunctional areas of a power utility -Generation, Transmission and Distribution. Itgenerates and distributes power in an unintemrpted mode at grid frequency. It has acluster of six generation units of different capacities. The largest rmit is of I I 0 MWcapacity followed by three of 77 MW each and two of 30 MW each. Two boilers are ofB&W, UK make, n'vo of B&W, USA make. The remaining two boilers are of Mitsubishiand ABL. Except one of BIIEL make, all other five generators are supplied by Siemens.The coal input for all t}e six units taken together is 6669 tonnes per day. The power tariffit offers to all its end users, is reasonably cheaper than many other power utilities in thecountry.

The growth in power in the DPL command area is around i0% per annum, the currentdemand being around 120 MW which is about 30% of the total power generationcapacity ofthe utility. It meets local demand through its captive kansmission anddistribution networks.

DPL's unit wise power platrt capacity, Coal input and Availability

:Coal Input MT/D

Boiler Make

iGenerator Make Siemens Siemens SiemensSiemens lSiemens

Availability (%) 100100

Bdw, inaw,

'.1

More about DPL

Durgapur Projects Ltd continuously strives at not only maintaining but improving thequality of its products further. Water, air and noise pollution is controlled bysophisticated equipment and monitored closely. The process control laboratories are fullyequipped with sophisticated and computerized equipments such CSR , CRI , GasChromatograph and Spectra Photometer.

The Environment Laboratory has state-of+he-art instruments such as Bacteriologicaltesting kits, Ambient air quality testing instruments , Stack monitoring instrument , Gasanalyzers , Noisemeter and Noise Surrey Systems.

Durgapur today assumes a significant position in the industrial map of West Bengal. Ithas a whole gamut of manufacturing units - fiom steel to power and from cement to

mining machinery. In the growth and expansion ofthis industrial base, Durgapur projectsLtd, the multi-utility company, wholly owned by the West Bengal Government, has beenplaying a pivotal role since early 60s. DPL-set up in 1961-is primarily a power utilityorganization but it has already made a mark in the market also as a manufacturer of worldstandard coke for various metallurgical applications. It also produces coke oven gas,which is being supplied to the neighbouring district of Kolkata. It produces another by-produc! namely, crude coal tar. It's rich human resources of450 highly skilled engineersand professionals besides around 5000-trained work force. A ll-member Board ofDirectors acts as a watchdog ofthe organization.

DPL today is a renovated and upgraded power utility. A total of six units of differentcapacities have an aggregate 4 I O-mega watt of installed capacity. After fulfilting totalrequirement of its command area customers, DPL surplus power goes to the West BengalState Electricity Board (WBSEB). DPL is the onlypower supplier within Durgapur.

One ofthe biggest advantages for DPL to serve itsclients is its production facilities being logisticallylinked with all the t}ree major modes oftransportation- rail, road and sea. Besides, Kolkataand Haldia in the qrst, ports like Vishirkhapatnam,Chennai in the south and Mumbai in the west alsohandle DPL products. Cutting across the states -from east to west and south to north- DPL is alsogearing up to spread its marketing wings abroad. The proposed list ofcountries includesSri Lank4 Bhutan, Dhaka and Quilon.

To ensure quality in every iep ofthe product processing, DpL has a well equippedlaboratory having sophisticated and computerized instruments such as GSR, CRI, GasCbromatograph, Spectro photometer etc. Environment is a key concern to the DpLauthorities. The Environment laboratory is equipped with bacteriological testing kits,

ambient air quality testing instrunients, stackmonitoring instruments, gas analyzers etc.

The sprawling township with adequateinfrastlucture facilities speaks for bpl,'s concemfor its most valuable resources-its emolovees.Besides adequate accommodation facilities, thecompany runs a hospital and an educationalinstitution to take care of its emolovees.

6

THER n*IAL PO }VER S.f A"TIO N

In thermal power stations. mechanicai power is produced by a heat engine that transtormstherrnal energy, often irom c(lnrbustion of a fuer, into rotatiol ' lal energy. Most tnermal p'lwerstations produce steam. and these are sDmetirnes callect steam gower stations. Not allth€nnal energy can Ile transfornred into mechanical power, according to me secon'f law 6fthermodynamics. Therefore. there is always heat tost to the environment. lf this loss is employedas useful neat, for industrial processes or cistric{ neafir 'rg. d]e power piant is referred to as acogeneration power plant or cHP (cornbined heat-and-power) plant. In countries where districtheating is cornrnon, there are dedicated heat plants called neat-only l loiier stations, An iinpodanttlass of power statiol ' ls in the Middie East uses by-product heat fDr the desalination of warer

A steam power statlon worl{s on tne Rankin cycle, stearn is proctuced In the boiler hy uti l izingthe heat of coal cornilustion that is then expanded in the prime mover {i_8. steam turoiney anois condensed to he fed Into the boiler again. The steam turbine drivds the alternator whichc'Jnvens meci'ianicaily energiy of turlline int6 eiec-rric energy. This type of power' stauon is suitahlewhere coal ancl water are avail3ble in abundance ancl a large amount of electric power is to begenefated.

Thermalpourer plant

I Coal conwaytr

Z Stoker

3 Pulveri?er

4 Boiler

5 Coal Ash

6 Air praheater

7 Eleclr'oElalicprecipitater

B Smok*slack

3 Turbine

L0 Candenrer

11 Trsnsforrneys

l? Cooling toweru

!3 General+r

14 HiEh-vdltsgepowar linas

In a thermal power plant. steam is produced and used to spin a turbine that operates agenerator. Shown here is a diagram of a conventional t l ' lertTtal powerpiani.whicn uses coal, oii.ol 'natural gas as fuel to boil waterto produce the sieam. The eiectricity generated atthe plant issent to cor)sumers througn high-voltage p'lwer tines.

Powat ttatlon tans

DEHNAnON: A fan can bc dafttpd as a volum*ftc machrna whrch fika Fumo mov.,squanddas o, alr & gas trom ona ptaco b arrofil'.t. tn doing so k ovarco;&'lCEtan"i t"now by supplylng the nud wnh ',le

enctgy n rcssary fot c-orrtatncC mot on.

FANS USED IN POWER PLANT Fo/R Bo.'LER HOUSE:

t: Fo-read Ora{t,Fan (F.D fan):- To-tak._air from atmosphGr. at ambirnt tlinparatur. torupply .''.ndalty at| tt.c combqstion atr can lattrrr ba 5t2.d to ov.rcom. rt't tnr lofloilosras {pra3surtz.C syst ml orjust put tfi. air In firmrcG (balanccd draft unlt3).2. In-ducGd Drart Fan (t.D fan):- urcd ohry in barancad drart unal' to suck ttra ga5.5 .rJt ofth. tr|mrc. A throlr, 1tt.m int? th. :ta9!!-Hrndt.s fiy ash tad.n gas.i at ta;p.ratur. of126-2txt c.g c. sp.cd r.ldom exc..d, tooor.p.m.

3. Primary Atr Fan (p-A fanl:- Us.d for putv.riz.d systam. Urualy 3tz.d ,or ISOO r,p.m du.to hlghar prossurc.

4. Saar Alr Fan:-t sed to s.al m||r baarings, coar ta.dars and coar pip.s In casa of prassuratyp. mill. Sp..d d€p.nds on th. typr ot arrangcmrnts ot tan.6-. Itnitor air Fan: - urcd to provrd. nlc._3sary combusdon alr to ttrc rgnitor. A controldamp.r ls provld.d on lhe dlacharg€ wrrlcn mdauliioi-to ii.tt t.ltt a conliini crirr-ri'nttaipr.33ur. labout 75mm ot w.ct acros3 tgntto, wh,r arry lgnitor ls h ;;t;;itt;;i;;;t460r.p.m.

6. Scannar Atr Fan:{rscd to provlda n.cqs3ary cooling alr to t'ra ,tama scannaf3. Typlcalsp.sd 3O(Xrr.p.m.

RldrnaradvG tcad haatino svstam

ECONOIdTCS OF FEED HEAnN6: _ t, s'E,am is btcd from a turbina ancr E mada up tEtalent and any supe ?€at Is may pos.s.ss tp e trcatgr, !trr, systlz, is caltaat fegancfa,vQ,bcc.rBa tt'c ftuid (s|r,am) grvq -ui t|f,at whtch wo.rtd dJimJiwsc waspc to ''rr-

GoNDENSATE SyStE/tt

A typical cond.nsat syst$ conslgts 0f tha following:-

1. Condenser (lnctuding hot_well)2. Condensate pumps3. Air Extracton4. Gland cooters & L.p.heaters system5. Deaerator

co roE rsERThe functions of condenser are:-a) To provrde rowest economic heat rejection temperature tor the steam Thus savrng on steamrequtred per unit of electticlty.b) To convert exhaust steam td water reuse thus saving on feed warer requlrement.

c) Oeaera6on of make-up water introducing the condenser.

-l{

e

di To form a convenient point for introducing make-up wate.

Tne above crlagram as named and pointed as below :

1. Chimney.2. lD Fan.3. ESP.4. FO Fan.6. PA Fan.6. SCAPH.7- Air Pre Heater.8. Ecsnomlzer.9, Feed Water Llne.to. Primary SH(LTSri).11- Final SH12. Platent Stt.13. Extended Steam Watl14. Reheater.15. Super Heated Steam.16. Cold Reheat Line.17. Hot Reheat Une.18. Boiter Drum -

19. Down Comrl ler.20. BR Header2t. Fumace.Z2.Bumerzil. \l/ind Box.24. ]{ot PA Header.25. Cotd PA Heacter.2€. Coal Mil t .2'I . Caal Crusher.28. Seal Air Fan,29- RC Burner.30. PC Pipes_31 . Water Platent-31. HP Turblne.33- lP Turhine.34. LP Turbine-35. Condenser.3€- Ejector.

3T.CondensatePump.39. Gland Steam Coolers.39. LP Heaters.40. Deareator.41. Bol ler Feed Pumo.42.HP Heaters.43. Makeup Fump.44. Circulating WaterPump.45. Water Treatrnent plant.46. Confot Structure.47. Generator_44. Hydrogen Plant49. Main Transformer50, Aux. Transformer51. Alr Circui t Breaker.52. Cooling Towers.53. CT Pump.

Coal tji Electricitv

ft -a.r

Trcat m.nt Plrnt

I

Essential Equipmerrts in poril,er Generation

Tulbihe

The conversion ts generaily accomplashecl by passing tne fiuad through a system of stationafypassages or vanes that alternate with passages cDnsisting of finlike b'iades ittacneo to a rotor.By arranging tne flow. so tnat a tangentiai force, or torqu-, is exerted on the rotor btades, tnerotor turns. and work is Bxtracted. A steam turlrine coniists of a-rotor resting on bearings andenclosed in a cylandrical casing. The rotor is tumecl by steam impinging agairist auainto vanesor blades on which it exerts a force in the tangentlal direction. inus a steam turbane coutct beyjeweg as a complex series of windmill-iike arrangements, alt assemblect on the same snaft.Here three types of turbines are used-(i)High Pressure TurbtneiHpt,(i i) lnterm ediate Pressure Turbine(tp).(iiilLovy Pressure Turhine{LF,

G€ncrator

G.e-neJators driven hy high-speed steam turbines are almDst always constructed wiul horizontaishafts. The rotor diameter is usuatly limiterl to a maximum of aglut one meter because of thehlgh centrifugal forces produced- HigrFspeed generators areiniroieo within a ctosed cytinclrlcaistator houslng illat extends between tne bearings at the two enos. Tney arJ .ooiio ny-dyorogrngas circulating witrtin the housing and also rrequentty through clucts within the stator conduerors.veqy',large generators are cooled by circulating waier tnroirgn tne stator and rotor conductors.This is a synchronous generatof-

Transformer

Device that tEnsfers electric energy from one altemating-cuffent clrcuit to one or more otnerclrcults, elther increasing.{stepping up) or reducing {step-ping clown) the vonage. Transformerschange voltage through etectromagnetic inductioruJf *-*:. ;ifletc tines of ,orce (flux unes)builrJ up and collapse with the cn-nges in current pdssing tnrouln tne primiryioil,'lune.rt i,induced in anouler coil, called.the seConoary.

-Ih-1:econgiiv uonaiu is calcutated hy multiptying

:19-q113.y voltage hy the ratio of the number or turns rn ine ieTondary coit to the number ottums in the primary coit, a quantity caflect the turn's ratio.Circuat braaFerA clrcult breaker is an automaticallFoperated electrical swltch clesigned to protect an eiectricatcircu.it from damage caused oy ovlrtdao or short circuit. rts nJs'i function is to detect a rauttconditlon and, by Interrupting continuity, to immediately discontinue electrical flow. unlike a fuse,which operates once and then has to tie reptaced, a circuit nreaxJi can be reset (either manualyor automaticallyJ to resume normal operation. circuit breakers are made in varyang sizes, fromsmall devlces that protect an inc,ivicluit nousehoto apprraniJuplo-trrg" switcng';Jide;rjnea toprotect high vottage cifcuits feeding an ertife city_

TYPES OF CIRCUIT BREAKERlvlany different classifications of circuit breakers can be made, hased on thelr features such asvoltage class, construction type, interupting type, and structurai features.

1, Alr Circult Brcaker2. Alr btast Circuit Breaker3, Tank type Butk Oit Circuit Breaker

rn

4. Minimum Oit Circui tBreaker

5, Sulphur Hexaftuoricte{SF6} Circuit Breai<er6, Vacuum Circuit Brealcer.

7, Low Voltage European Circuit Breaker

Coofno Tow€rs:

Ail tfiermal power piants produce waste neat as a byproduct of the usetut electricat energyproducecl. Natural dr_^ajt wgt,gooling towers at nuctear power plants anct at some large fosii lfuel -fired

power plants_ use lalge hypErtrotic cnimney-lii(e structures (as seen in the tmage atthe left) that release the waste ne# to the ambienf atmosphere oy'ure evaporation of wateriiovter left image). However, the mechanical Induced-draft or force+draft wit cooling rowersias s"-en in tl |e lmage to the right) in many large.tnermal power ptants. {nuclear power ptants.fossii fired power piants. petroleum refineries, petrocnemiial plants, geotrrermir,'lriomass anowaste to energy plants use fans to provicte air movernent upward thiough do,r/ncoming waterancl are nol hype.boljc chiftney-like sffuctures- The inducect or rorce+orEft io6ting rowers aratypically rectangular. box-like structures filled with a material that enhances the coniacting of theupflowing air and fl1e downflowing datef.In areas witn restricted water uie a dry cooling tower or radlator. dlrecfly air cooled. may benecessaly' since the cost or environrnental consequences of ontaining make-up water forevaporative cooling woulcl he prohibitive. These have lower efficiencf inc nifnur energl/consumption in fans than a wet. evapo(ative cooiing tou/er-where- economicalfy and environmentalty possibte. etectric companies prerer to use coogngwater from the ocean, or a iake rrr rivef, or._a cooling pond, instead of ; looring iewer. Thistype of coollng can save the cost of a cooting towei bno may nave lorrver ene-rgy costs forpumping cDoiing water through fte planfs heat exchangers. Hcwever, tne wasie heat cancause-the temperature of the water to rise. cletectably. P*orryer ptants ustng natural bodies ofwater for cooling must be designed to prevent intake of brganisms into the cofiting itiie.

Generator Transform€r

Regarding to physical size of national power systerns, rate 6f power excnange and transmissionlines capacity are increased. oy usJhg or -6ign

voitage G[nnorogy. step up or generatortransformers incrsase the produce,: vditage of piwer gerGrator! in griAi powlJr pilnts. Tnereforeit seems the unique tunction of these traniformers is the increasing-of generatoi voltage equat tovoltage of nationat grid.

But as you know. in small and individual pow€r systems (e.g. industrial power ptant andrelated power distribution system) the generator transiormers'are used as thd electromagnetcIntefface stage between g.enerator ano powe_r clistribution system- tn this mentioned system thetransrnission anci distriilut,on voltage is'rfiedium voitage, ttiererore output of generator may beused directy in distribution system -

Coal mlll I

A pulverized coaLfired boiler is an inclustrial or.utillty boller fl'lat generates thermal energyby h.uming putverized coal (also known as po\fldereo coat or coat dust) This type of boilerdominates tne electric power industry. providing steam to ctrive targe turbines, pulverized coalprovides the thermal energy which produces about 5oo/o of ffre worlo'i elecfric supply.Raw coal is fed througn a lentral ioat inlet at fte top or tne pulJerizer andfalls by gravriy to therBtating grincting table, mixing with classifier rejects returneb for re-grinding. centrifugat actionforces the coal outward lo tlle. grinding ring wnere it is putverized h;twee; the nng and threegrinding rollers- Grinding load. trinsmitieo rrom the tensioh rods through the lo;dlng irame to theroller assemtll les, nolds the rollers in contact_wim me grinding nng The roilers adjustverticalryas the depth of tfie coal loacl increases or decreases. A noz]zle ring on the outside perimeterof the grinding ring feeds prirnary airto the putverizer pyritei-Jno trarnp rnetat fa1 through thenozzle ring openlngs to be scraped into a re1ects noppjr. A sveam of low-veiociry atr carrtes

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The steam generating plant consists of boiler for production of steam and other auxiliaryequipment for the utilization of fuel gases.. BOILER

A boiler is an indispensabie part of a thermal power plant. In a boiler, we burn thecoal to produce heat energy. This heat energy will make the water to superheated steam.Then this steam is used to rotate the turbinJiotor into ve.y trigrr speed. From boiler,steam passes through superheater, economizer, and air pre-lreater and then passes throughchimney to atmosphere.I.n Dyepur Project Limited, there are six boilers. Here is the unitdescrintion- boiler

o STEAM TURBINEt:tffXY}:.:^:4i]yv of ttr; steam is first converred into kinetic energy is

:::'l:: :: ?l g: tf :"q1 ruj err, velo c i ty steam fail s on trre .-ilffi ffi; n,.. j'"-J j "..r,universally used as primemovers in all steam power plants.

o SUPERHEATERrnt tGutn p,oGd in the utiter is wet and is passed through a superheater whereit is divided and superheated by the flue gases on_ theiiway to chimney. Superheaterprovides two principal benefits firstly, the overall effrciency is increased. s"rorrJiy toomuch condensation in the last stages is avoided. The superheater steam is fed to tr-ubinethrough the main valve.

. ECONOMISEBit is basically a heat changer by which the temperature of feed water, comingfrom high pressure heater is increasedto the saturatioi temferature or slightly less thanthe saturation temperatue. corresponding to the drum pressure. The fed water is fed toeconomizer before supplying to the boilir. The economizer extracts a part of heat of fluegas to increase the feed water temperature.

r AIRPREHEATER tAn air preheater increases the temperature of the air supplied for coal burning byderiving heat from flue gasses. Air is or?v1n from the ut-orpt

"r. by a force draught fanand is passed through airpreheater supplyirlg to boiler nrmJce. The air preheater exractstie.at {rgm nut gut.i and increases the temperature of air used for coal combustion. Theprinciple benefits of heating the air increaJed thermal efficiency and increased steamcapacity per sq. meter of boiler surface.

wlsenDuon-Description Unit I Unit 2 Unit 3 Unit 4 Unit 5 Unit 6BolierMake

Babcock& Wilcox,UK

Babcock& Wilcox,UK

Babcock9,E

Wilcox,UK

Babcock&Wilcox,UK

Ir4itsubishi ABL

Coal(Mr/D)

504 504 t '260 t260 1293 1 848

o ALTtrRNATQR

3t3

i^The steam turbine is coupled t. an altcrnat.r. '[-he alternator con'crts mechanicar energyof turbine into electricd tncrgy. 'ttrc clectricot outpuirr-o'i the alternators is cielivercd tothe bus bar through transfornilr circuit Lreakers and isorators.

" ELECTRO.ITATIC. prrECrprT.{TOR (ESp) D'

There is variou gat tl"*[iiui."r. a.i]iililem prate tvpe of erecrrosraricprecipitator is very usefur as it gau."99y",efficien;;."n;tn"ipr. components of anelectrostatic precipitator are trvo set.s of electroderinrluiu,lJ from each orher. The firsr setts composed of rows of electricallv grounded ".;;;i;i;il cartea collecring erectrodesbetween which are dust laden gas i" n"*r.'n. ...oni ,.iJf er.ctroaes coisists of wires,called the discharge or emitrin! erectrodes rhar.are

".";;;;i"cked each pair pararel*i?#:.ash

particles are coil"tt"J in rtre cotte.,irrg.r.rirodes and ger ..;up;rared fromSPECIFICATION OF E.S.P.

IN EACH SERIESNO Or'etrarrren pr-are vt l

4*66* I

. BOILER FEED ptjt\tP

B4_IED PowER (KREVOLUTION PER

UENCY (HZ PHASE (MINUTE_.-*

STATORINSULATION-CLASSRO'foREFFICIENCY h%POWER FACTOR (COSTOTAL WEIGHT (KCMANUFACTURED Bi

RREL CAGE

NO OF TBANSpOnrvfEnTRAFO RECTIFIER sET

n4?7 Aot-HA 43180DC VO[-T (KV

CU RRENT (AI\4pS l, pH,q.S H o,360,157voL17m49.45, l . 148

HINLANDM

4, 6600v,400 A

t4A' l

i^

. INDUCED DRAUGHT FANI

CTIJRED BY CI{OIviF'|ON GREAVES

RATED POWER 671.4 KW / 900 HPREVOLUTION PER MINUTE 740FREQUENqY (HZ), Pr{ASE (0) -50, 03RATED VOLTAGE (VOLT) 6600RATED CURRENT (AMP) 1A

,a

RATTNG MCRINSULATION CLASS FDU'1'Y st, cD (MOTOR)ALT 1000 MAMBIENT TEMPERATURE CMANUF

I. FORCED DRAUGHT FAN:

r EI-ECTRIC OIL HEATER:

RATED CURRENT (AMP^a.+)

-RATED POWER, PHASE (6)

6600375 KW / 5m HP. 03

REVOLUI'ION PER MINUTE 988POWER FAC'|OR 0.8MANUFAC']-I.JRED BY BHEt,

TYPESERIAL NO

INDIREC'Tt -84.6C1-0S I

NO OF ELEMENTS ti0POWER (Kw) 60BATED VOLTAGE (voLr) 440lFrArE (0) 03MANUFAC'ruRED BY PENNWALT INDOAT LIMI'TED

\>

ALTERNATOR

A'c' generators are usually ca'ed alternators .lhey are also called synchronousgenerators, Rotating machines that rotates at a speed fixed by the supply frequency andthe number of poles are called synchronous machines.

:. goNSrRUCrIoNsimilar to the other rotating machines, an alternator consists of fwo main partsnamely' the stator and rotor' The sltor is the stationu.y port orthe machine. It carries thearmature windins in which the voltage is generated. rire butput of the machine is taken

fr:,T;rfi*. rheiotor ir tr'..olutinJi;; ortn.

-*rri,,* il.,oro,produces rhe main

l .wucrroNThe various pattt oFth"Gl*clude the frame, stator core, stator wi'dings andcooling arrangemen!. The frame rnuy u. or cast iron for'small size machines and weldedsteel type for large size machines. In order to.reduce hysieresis and eddy crurent lossesthe stator core is assembred witrr hilrr giade silicon .on*ni *."r laminations.

2. tgro4 coNsrRACrroN

"r,,"*HTl,T#: tvpts.Ft6Gristruction namelv, the salient pore type and

The term salGnt il)oles nroiecrino nrr+ ffJ::::lfc

or projecting' Thus, a salient pole rotor consists .f:.*::**':,9,-",::3:T3;'y".i;"d;#."J:b;;*fi :tJiffiffi:";ff;"':::,ff;,orporesand operate at lower sneerl sn ir dri'o- L' r,,^+^- !--L:and operate at lower speed,o it ariu"n d;Jilffi; mes called hydro alternators or hydrogenerators.

A cylindrical rotor machine is also called a non salient pore.rotor machine. It has its rotorconstructed that it forms a lmooth cylinder. The cylindi.ui roto, lvpe alternator has rwoor four poles on the rotor. cylindrical rotor type aiternators are driven by steam or gasturbine' cylindrical rotor fype alternators ara called turboalternator or turbogenerator.The machines are bu't in iit"*u.i "ii^rings

from to Mv,ito over 1500 MVA.In this plant cylindrical rotor typ. uri..nrors a{e used for generation.

*Excitation *"*ip-tffii by passing curent in the field winding. In

for excitation.this plant there are two types of system usedr) D.C. SYSTEMDirect current is required to excite the field_winding on the rotor of the synchronousmachine' D'c' is supplied to the rotor field uy u o"!"n"raiol cdteo exciter. Ths exciter issupplied current by a smaller D.c. generator caltedlilot exciter. The main and pilotexciters are mounted on the main siaft of ,fr" alternator.

lindrical rotor

2) A.C. SYSTEM

\6+

There are two types of ac excitation system. Rotating system: this is a high frequencyexcitation system' pennanent magnet pilot exciter and uncontrolled rectifier. staticexcitation is generator fed static excitation system with controlled rectifier and rectifiertransformer.

* coqLING SYSTEMIn this plant cooling is done in unit 1 and 2 by air. The closed circuit air closedgenerator has shaft mounted fans for circulation unaiori"ontur water cooled air coolersare mounted in the hot duct. rn case of unit 3,4,5 hy;;;;;;';oo[ng is done. Fourhorizontal hydrogen gas coolers are axially *o*t"j'on ti;i;p half of the generatorcasing.

B I }

SPECIFICATION OF ALTERNATORS

r UNIT NO 1&2 ALTERNATER

RATED VOLTAGE r 1000v+-7.5%VRATED CURRENT 3440ABASE MVA 37.5 MVAPFIASE I

J

SPEED 3000 R.P.MFREQTJENCY 5OHzPOWER FACTOR 0.8EXCITATION 205 VOLT! ,408AmpCONNECTION YYMANUFACTURED BY bNUHLISH ELECTRIC

. UNIT NO 3&4&5 ALTERNATER

RATED VOLTAGE 11000V+-75%VRATED CURRENT 4650t4600t4330/3940ABASE MVA 88.s I 81 .5 t82.5 /7 s.0 MVA

3000 R.P.M

POWER FACTOR 0.87l0.88/0.8/0.9EXCITATION 3 81 /37 21384/366Volts,665 I 650 I 67 0 I 640

FOR F]2 COOLING 1.05/1 .05/0.5/0.065 KG/CMMANUFACTURED BY

e UNIT NO 6 ALTERNATER

.I'\TDtrL LL L

t TGP 234260t2HRATiNG UUN I INIOUSHYDROGEN PRES SUREE(AlI\d) 2APARENT O/P (KVA) 137.500ACTTVE o1P (Kw) I IU,UUUPOWER FACTOR (COSd) 0.8 LAGRATEp VOLTAGE (VOLT) I 1000RATED CURRENT (AMPS) 220REVOLUTION PER MTNUTE 3000FREQUENCY (HZ) 50PHASE CONNECTION YYGENERATEI{ TERMINAL oMANUFACTURED BY SIMENS

'l t8

TRANSFORITER

r INTRODUCTION:A transformer is a static device which consists of two or more stationary electric

circuits' Interlinked by a common magnetic circuit for the purpose of transferring electricalenergy between them. The transfers of energy from one circuit to another takes place without achange in frequency.

r CORBThe transformer core is a closed magnetic circuit through the mutual flux i.e, the flux

which links with both the rvinding passes. The core material and construction should be suchthat both the magnetizing current and the core tosseb are minimum. The cores of transformersare laminated in order to reduce eddy current losses. The laminations are generally made up of0.33-0.5 mm thick. These laminations are made of the so called transformir grade steelcontaining 3-5% silicon. The steel used for transformers are generally hot roilerj or cold rolled.But in recent years cold rolled steel is preferred over hot rolled as it allows much morE fluxdensities up to about 1.8 wb/mz.

. BUSHINGSTransformers are connected to higlt voltage lines, and, therefore, care must be taken to

prevent flashover from the high voltage connection to the earlhed banks. The bushing consistsof a currert canying part in the form of a conducting rod, bus or cable, a porcelain cftinO.1.installed in a hole in the transforrner cover and used for isolating the curint carrying part. Thesimplest bushing is a molded, high quality glazed porcelain insulator with a.onju.ioi rhroughits centre. This bushing is used {or voltages upto 33 KV.The bushings used for transformershaving voltages above 36 KV are either oil filled or capacitor fype.

. TAP CI{ANGERThe voltage of power-networks supplied by transformers can be controlled by changing

the ratio of transformation of the transformers. The change in ratio of transformation can beaffected by providing tappings on the transformer windings.Ihe tappings are connectionsprovided at different places in the windings and therefore, the number of tums included in thecircuit at one tap is different from the number of turns at another tap. The tappings may bechanged when the transformer is disconnected from the supply. This is called ofi-circuit tapchanging. The off-circuit tap changing is used for occasion;l adjustments, as in distributiontransformers. The tappings can also be. changed while the transiormer is energized or on load.This is known as on load tap changer.-

FERRANTI TAP CHANGER GEAR:

NO, OF POSITION T7RESISTOER VALUE . 0.855c2SUPPLY TO MOTOR 230 V.OIL QUANTITY:SWITCH COMPONENT 382 LTR, (330KG)GEAR BOX 137 LTR, ( l lSKG)WEIGHT (EMPTY) 715 KCTOTAI., WEIGHT l l63KGMANUFACTURED BY SIEMENS

t0

o COOLINGth" ttansflo.mer is a static device which converts energy at one voltage level to another

voltage level' During this process of energy transfer. losses occur in the windines and coreof the transformer. These losses appear as heat. The heat developed in the trans-formers isdissipated to the surroundings. For this emission of heat, coolingbecomes necessary intransformers.

The different types of cooling involved in transformers are:l. Oil natural air natural.2. Oil natural air forced.3. Oil natural water forced.4. Forced circulation of oil.

a) Oil forced Air natural.b) Oil forced Air forced.c) Oil forced Water forced.

. WINDTNGSThe anangement as well as construction of transformers varies in shell and core type

transformers. Shell type transformers use sandwich type of winding with coils shaped inpancakes. In that case L.V. and H.V. windings are split up into a number of coils. h,ach highvoltage coil is placed between two low voltage coils. This subdivision of H.V and L.V coilgives a bener coupling between the two windings. Concentric type of windings is prefened forcore type of transformers. Each limb is wound with a group of coils consisting of both primaryand secondary windings which are concentric to each other.

tq

19l lI t

r GENERATING TRANSFOBJVIER FOR UNIT(l&2)

There is a reactor that limits the fault cunent. The rating of the reactor is 6.6 KV. It isused for feeding 6.6 KV for the plant.

. GENERATING TRANSFORMER FOR UNIT(3&5)a

r GENERATING TRANSFONMN,N FOR UNIT 4

KVA RATING (KVA) 37s00RATED VOLTAGE(AT NO LOAD)KV)HV SIDE r32 f,vLV SIDE 6rvIMPEDANCE VOLTAGE AT 75"C I I .I O% AT ABOVE RATINGCONNECTION SYMBOL YndlFREQUENCY 50HzWEIGHT OF CORE & WINDING(tones) JJ

TOTAL WEIGHT (tones) 66

QUANTITY OF Oll(gallons) 4048MANUFACTURED BY ENGLISH ELECTRIC CO LTD.

MVA RATING (MVA) 42.5 59.5 85RATED VOLTAGE(AT NO LOAD)KV)TIV SIDE t32 lcvLV SIDE I I KVLINE CURRENT(Amns)HV SIDE 372.22LV SIDE 4679.3CONNECTION SYMBOL YndlFREOUENCY 5OHzTYPE OF COOLING ONAN.ONAF.OFAFTEMPARATURE RiSE OiL("C) 40TEMPARATURE RISE WINDINGfl C) 55

MANUFACTURED BY B.I{.E.L.

KVA RATING KVA) 85000RATED VOLTAGE(AT NO LOADXKV)HV SIDE t an

L)Z KvLV SIDE : ' l l KVLINE CURRENT(Amos)FIV SIDE 372LV SIDE 4680CONNECTION SYMBOL YndlFREOUENCY, 5}HzTYPE OI"- COOLING oFw

2lt1,

EARTHING TRANSFSRMER

EARTHING TRANSFORMER (CONNECTION DIAGRAM)

2U2V2WN

RATED VOLTAGE (V) 33000FREQUENCY (HZ) 50NO OF PHASE (0) 03CONNECTION ON SYIV{BOLS ZTYPE OF COOLING ONAN,TOTAL MASS (KG) I 980VOLUME OF INSULATING OIL (LTR) s50INSULATION LAVEL CLASS ARATED SHORT TIME CURRENT &DURATION (AMPS, SEC)

287,30

ZERO SEQUENCE IMPEDENCE 209,9MANUFACTURED BY TRUVOLT ENGG. CO. PVT. LIMITED

(KOLKATA)

ELECTRIC OIL HEATER:

SERIAL NO r -84-60-09 INO OF ELEMENTSPOV/ER (KRATED Vo.TAGE_ryoL

MANUFACTURED B' PENNWALT M

lapggEp DRAUGHT FAN:VITED POWER

671.4 KW / 900 HPREV O L Ufi O-N PER M INL]TEFREQUENCY (U.),PHASERATED VOLTAGE CVOLRATED CURRTNTAMP

TNSULATiONTLASS

sI, cD (MOTOR

AMBIENT TEMPMTUREMANUFACTURED BY CROMPTON GREAVES

FORCED DNEUGHT FAN:RATED CUNNEIVT GRATED VOI-AGE CVOLRATED POWsuHase 3?5 KW / 500 HP, 03REVOLUTION PER MTNdiEPOWER FACTORMANUFACTUNTO ET

FERRANTI TAP CHANGER GEAR:NO. OF POSITIONRESISTOER VALUEqulll.Y ro MOroROIL QUANTITY:swrTCH qOMPONENT

382 LTR, (330KGllzlTR, (l tsKG715 KGTOTAL WEIGHT1163KGMANUFACTURED BV

AIR BREAKER ISOLATOR:RATED VOLTAGE ryOLRATED CURRE TTGMPSSHORT CIRCUITTTME (^-il4PSII\4IlLSE VOLTAGE r050 KV

1000 Kc/AS&S POWER Gean r-ilr,rlTeD

MANUFACTURED BY

TRANSFORMER RECTIFIERVOLT AMPS RATING(KVA)

16 CONNECTION SINGLE PHASE OPENBRIDGE CONNECTION

TREQUENCY (HZ) 50 PEAK DC VOLTAGE ry) 70000PHASE (d) 0l AVARAGE DC cuRRENr (l'vrps] 0.23low voLTAcE SrDE (V) 380 AMBIENT TEMPERATURE 6OUCCURRENT (AMPS) A1 1 wErcHT OF CASE A Flrrnqc Kcl 600HIGH VOLTAGE SrDE (-V) 53300 WETGHT OF THE OIL (LTR) 580CURRENT (AMPS) 0.3 rorAi, WETGHT (KG) 1 550% IMPEDENCE s.79 MANUFACTURED BY BHELWEIGHT OF THETRANSFORMER (KG)

430

l+ 2-3T SILTCON RECTIFIER POWER UNIT:

. BOILER FEED PUMP

?_!!{D U C T I VE VO L TA G E TRANS F o RM ER :

:CAPACITO R VO LTAG E TRANS F O RM ER

B4TED PowER (Kw) 4000REVOLUTION PER MINUTE 2986FREQUENCY (HZ), PHASE (d) 50, 03STATOR 4 6600V,400 AINSULATION CLASS BROTOR SQURREL CAGEEFFICIENCY (n%) 96.6POWER FACTOR (COS 0) 0.914rgTAL WETGHT (KG) 22000MANUFACTURED BY BHEL

A.N ia- lnVOLTS 15000/{3 r00/{3BURDEN (VA) 300ACCURACY CLASS 05HIGHEST SYSTEM VOLTAGE (KV) 170THERMAL LIMITING O/? CVA) 1 500VOLTAGE FACTOR 1.2 CONT /1.5-3.00 SECINSULATION LAVEL (KV) 325 I 750TOTAL WETGHT (KG) 575 xt}%V/ELGHT OF OrL (Kc) 100 r10%MANUFACTURED BY CROMPTON GREAVES

FREQUENCY (HZ) ' 50Hsv (KV) LlU

TNSULATION LAVEL (KV) 325 I 750EQUIL CAPACITANCE (pF) 4400 + 10Vo -5oAcAP OrL (KG) 35 + r00AEMU OrL (KG) 65 + l jyoTOTAL WETGHT (KG) 450 + IjyoVF 1.2 CONS / i ,5 -30 sEC

A.N la- lnVOLTS 1 s000/{3 100/!3BURDEN (VA) 200ACCURACY CLASS 1.0MANUT.AC |URED BY CROMPTON GREAVES

L4t \

. PROTECTIVE RELAYS:

it detects the fault and initiates the operation of the circuit breaker toisolate the defective element from the rest of the system .The relays detect theabnormal cbnditions by measuring the electrical quantities rvhich are different undernormal and fault condition.

A fypical relay circuit has three parts - (1) the primary winding of a currenttransformer (C.T.) connected in series with the line to be protected. (2) Second part consistsof secondary winding of C.T. and relay operating coil. (3) It has a source of supply, the tripcoil of the circuit breaker and the relay stationary co?tacts. With a short circuit current in theline increases enonnously and a healry current flow through the relay coil causes the relay tooperate by closing its contacts and it closes the trip circuit of the breaker making the circuitbreaker open and isolating the faulty section from the rest ofthe system

(1)Selectivity (2) Speed (3) Sensitivity (4) Reliability (5) Simpticity (6)Economy.

o Basic relays: These operate with the current or voltage supplied by transformersconnected in many combinations to the system element to be protected. The two mainoperating principles are Electromagnetic attraction and Electromagnetic induction.

o Distance or impedance relays: Here the operation is governed by the ratio ofapplied voltage to current in the protected circuit. The torque produced by acurrent element us opposedby the torque produced by a voltage element .Therelay will operate when the ratio VA is less than a pre-set value .In operation, thevoltage element of the relay is excited through a potential transformer (P.T.) formthe line to be protected.'The current element of the relay is excited from a currenttransformer (C.T.) in series with the line.

. Translav relay:Here the balance or opposition is between voltages induced in the secondary

coils wound on the magnets and not between the secondary voltages of the line currenttransformers. Since C.T. used with translay scheme have only two supplies to a relay coil,they can be made of normal designs with out any air gaps. It permits this scheme to beused for feeders ofany voltage.

r Bucholz Relav r'

It is a gas-actuated relay installed in oil-immersed transformer to protect againstfaults.Construction: IA domed vessel is placed in the connecting pipe between the main tank and theconservator with two elements the upper element has a mercury type switch attachedto a flsat. The lower element has another mercury type switch fixed on a hinged typeflap located in the direct path of the flow of oil from the transformer to theconservator. The upper element closes an alarm circuit during incipient faults but thelower element trips the circuit breaker for severe internal faults.

L{l rt t )

* BUS BABUATEruAT

Flere mostly Aluminium pipes confirming to IS-5032 are used to anangethe rigid bus connection. The size of the conductor depends on the voltage like:-

1. 40 mm2. 65 mm3. 80 mm4. 100 mm

The materials commonly used for the bus bar and connection of strain typeare ACSR and AAAC.Bundled conductors are also used but with higher rating or toreduce corona losses.

The bus bar material and size of it should be able enough for the electricaland mechanical requirements of the application for which they are chosen.

When a number of lines operating at a same voltage have to be directlyelectrically connected.

e Bus bar arrangsment

Single bus bar arrangement.Single bus bar system with sectionalisation.Double bus bar anansement.

The bus bars and the connection are supported on pedestal insulators. Asthe bus bar is rigid, clearance is remaining constant. The distance between bus bar andground is not very large so maintenance is easy. Now due to the large diameter of thepipes the corona iosses are considerably less. The systern is more stable then the straintypes.

* CIRCUIT BR.EAKER

A circuit breaker is a piece of equipments which can:-i) Make or break a circuit either manually or by the remote control under

normal condition.ii) Break a circuit automatically under fault condition.iii) Make a circuit either manually or,by remote control under fault

condition.A circuit breaker is consists of fixed and moving contacts remain closed and

not open automatically, until the system became faulty. When fauit occurs

then the trip coils of the breaker get energized and moving contacts are pulied

upuri, thus the opening the circuits under fault condition when two contacts

are separated then in that small space between two electrodes a high voltage is

a)b)c)

I

L\.t+

. CLissif ication of circuit brc:rkr:rs

a) Bulk oi l circuit breaker'b) Minimum oil circuit brcaker'c) Self blast oil cirdfrtbriaker.d) Forced blast oil circuit breaker'

e) Axial blast air circtrit breaker'

D Cross blast air circuit breaker'

B) Sulphur Hexa Fluride (SF6) circuit breaker'

h) Vacuum circuit breaker IVCB)'

Llorvever, now vAccUM and SFo circuit breakers are mostly used'

The circuit breakers are normally mounted on individual structures' The circuit breakcrs

have fixed locations and the station la;'out is ii', such a \\'ay that adequatc scction

clearance is al..va)'s from the live parts.

. MINIMUM OIL CIRCUIT BREAKER (MOCB)

. SFoCIRCUIT BREAKER;

9545, l 52. IASME SIrC VII IDIVlDESIGN CORE

CAPACITY (LTIT)wonrctNc PRESSURE (KG/CM')TEST PRESSURE (KG/CMMANUFACTURED BY

RATED VOLTACE (KV) 145

NOnunl cuRRENr (AM!!) 3150DDENI I t rNTT\/ (H7\ 50

650NETEN LIGHTING IMPULSE WITI{S'I AN I-)\T^I T^T-: t r PtrAK {KV\

t vsr " . . . -

" r r _

ffinreclqL 1.540

DURS'| ION Oh SHUK I UII( \ ,UI T

St-tonr ctncutr enEnruNc cuRRsry!SYMMETRICAL (KA) ' -

4044-8ASYMMETRICAI. (KA) -- -- - *

SHOPRT CIREUIT MAKINC CURP.ENTPEAK (KA) -ouT oF PHASE BREAKiNC cu4BsNT'154)

r00

100-0.3s-co-3MIN-CO6.4 BARSFr, OAS PRESSTJRE AT 20"C' lOlJ l lpa

roTAt- MAss oi' sFo GAs (KG) l ' )

TOTAL WEIGI. I I ' (KG) I 402

tdla

ISOLATORBy isolator rvc disconnecIrepai ri n.t purpose. Isolator

i) I ' lorizontal ly.i i ) Vert ical ly.

lll9gT crRCUr f |rN,,r:AMI'S

a part of the system for general maintenance andare t\\'o types

r 60076.24

Horizontalry isorators takes more space than the verticaill, isorators. In asubstation horizontaty isorators ar6 preferred ;.;-;;i,. tr tot ",

ma-ximurninfluence or substation layout.

r AIR BREAKER ISoLAToR:

L4TED VOLI'AGrI ryoLRATED CURRENT (AMPS

IMPULSE VOLTT\C,I r050 KVWEIGHT1000 KG/AMANUFACTURED BY S&S POWER GEAR LIMII I .D

, l t 2g

CURREI{T TRANSFORMER

This is a step down transformer which steps down the current into a known ratio.Current transformer mainly two types:

i) BUSHTNG TYPEThis type of current transformer is used normally within the

transformer busing.iD woulYp IYPE

These are simply mounted current transformer, normallybackbone of the substation. The complete layout of the substation with piotectionis very much depended on the .urr.ni transforrner. The location of currenttransformer must proportional with the location of the circuit breaker.

This is a step down transformer which step down the current inknown ratio.

RATIO VA CLASS ISF ALF VK600-300-150/5A

60 5P 10 200

600-300-i50/5A

60 5P 10 200

600-300-150/5A

60 0.5 1.5

INSULATION LEVEL 6501275KVSTR 26KAl3 SECMANUFACTURED BY TARIT APPLIANCES & EQUIPMENT PVT. LTD.

L){ro

{. POTENTIAL TRANSFORMER

. This is a step down transformer which step down the voltagem Known ratlo.They are two types:D Electromagnetic type.ii) Capacitor type.

capacitor type potential transformers are cheaper thanelectromagnetic type. Electromagnetic type potential transformers are used wherehigher accuracy needed. ln normal application capacitor fype potentialtransformer are used for higher voltage due to lower cost.

For synchronization purpose, another type potential transformer isused' Potential transformers are also connected on ihe feeder side of circuitbreaker.

o INDUCTIVE TYPE POTENTIAL TRANSFORMER:

r CAPACITIVE TYPE POTENTIAL TRANSFoRMER

BURDEN ryAACCURACY CLASSHIGHEST SYSTEM VOLTAGE (KVTHERMAL LIMITING O/P ffAVOLTAGE FACTOR 1.2 CONT /1.5-3.00 sECINSULATION LAVEL 325 / 7s0IOTAL WETGHT (KG 575 t I j%xiElcHT oF OrL (KG) 100 r10%MANUFACTURED BY CROMPTON GREAVES

FREQUENCY (HZ) 50HSV (KV) T70fNSULATION LAVEL (KV) 325 I 7s0EQUIL CAPACITANCE (pF) 4400 + t0% -5%cAP OrL (KG) 35 !. r0%EMU orl ({c) I 65 ! 10V,IqrAr wErcHr (KG) 450 + 19o7"VF 1.2. CONS / 1.s -30 sEc

A-N la 1nVOLTS 15000/a/3 100/{3BURDEN (VA) 200ACCURACY CLASS 1,0MANUI.-AC URED BY CROMPTON GREAVES

1r 2bcLl

O IIIGHTNING ARRESTERl

A Substation has to be shielded against direct lightning strokes eitherby provision of overhead earth wires or spikes. The choices between the two methodsdepend on several factors, economy being the most important consideration among them.Generally spike method involves structures than the alternative of using earth wires.Some time separating lightning wastes are used on the sub station on basis of the substation area and height of the bus bars. Generally an angle of shield of about 450 for thearea considered-ailequate-fo} the design of lightiring protection arrangement.

Without direct strokes, the sub station devices have to be protectedagainst traveling waves due to the lightning strokes on the line entering the sub stationand for this purpose lightning arrester is used. In a sub station the most importantequipments are transformers so, lightning arrester are situated near transformers. There isa insulation co-ordination with the lightning arresters with each equipments present in thesub station. As the focal point of the investigation. The power frequency and over voltageexceeding the rating on the arrester should be calculated.

Classification of lightning arrester is:i) Rod gap arrester.ii) Hom gap arrester.iii) Multigap arrester.iv) Expulsion type lightning arresterv) Valve type lightning arrester.

. SPECIFICATION OF LIGHTNING ARRESTER

RATED VOLTAGE (KV) 110RATED CURRENT KA). uS 10, 10/20SHORT CIRCUIT CURRENT fi(A). uS 100, 5/10RESIDUAL DISCHARGE VOLTAGE(KV)

73.24

ISL (AMPS) 400MANUFACTURED BY SIMEANS - S CHEKERTWERKE

z1

Max steam Pressure =721<g/cm2At turblne lnlet

Feect tank temperature =158'c11't extracflon bteam quantity =15 ton/hrF.W. outlet temPerature =215'c2nd extraction pi:essut-e = ! 3-7 kg/cm2

2nd extraction steam temP- =3O4'ci"o extractlon steam quantity =16-9 ton/hrF.W. temperature =158'c

4s exsaction pressure =3-31 t(g/Cm24tr extraction bteam temP. =168'cS extracuon steam quantity =15'4 ton/hrF .W. tem P in VAC heat =88 '2'ccondensate temp- in hot-well =45'c

THE 7jh ullr:r QF -DqL

=9358cu.m=<4.652MWm^2

| =<' l .582MWm"2

1. Fumace ddailsi)Furnace Volumeiiltvtax net neat input per unit plan area

iiiltvtax bumer zone heat release rate

2. SH/RH/Economtz€r tub€ PichingPrimary HeaterPanel Divlsion superheaterPiaten SuPerneater

detalls= 1 l4mm=61mm=64mm (outermost space ls 67mm)

3L

= 102mm=50-8m=70mm= 120mm= 102mm

3. Mll lsi)Total no. Of Mltts =6 mins!i) ry" of miils required with worst coat =S miftsi lr) No. of mll fs requlred wlth design coaf =4 mii ls

4. IDiFDIPA fans

l lYlgil on Frow(%) (Based on 50% BMCR frow)PA FAN:4006 FD FAN: 2Oolo tD FAN: 2oololi) Margin on Head (%) (Based on SO% evrCn fiowjPA FAN.4O06 FD FAN: 4Oolo ID FAN: 4oolo

5. Elcctro-staGlc prccipltatorl) No. of etectric fietds in sefiesli)Specifi c C oilecting Arealii)Treament fimelv)cas Vetocityv) Coftecting etectrode spacing

6. DuctThiclrncss

Final Superheaterwalt ReheaterMedium ReheaterFinal ReheaterEconomizer

l) Air ductsii) Gas ducts

7. TurblnoRated OutputFresn PressureFresh TemperatureReheat TernperatureRated SpeedExhaust Pressure

9. Tnrnrf,ormcrNo- of Transformer,)Unlt Auxitfary Transformer A

=6mm

Before ESP plate thicl<ness =gmrnAfter ESP ptate thfckness =gmm

=7fieids=247 -48m^Am^3/sec=39secs=O-63m/sec=3OOmm 1rs S tTetds)& 4OOmm(tast 2 f ietds)

=3O0MW=16-67MPa=537cteg. C=537cieg.C=30O0rpm=0-O096MPa

=3(2untt&lstat ion)

L GincratorXaled Capactty =3S3MVAFaleq 9utput =eooMWlpr.ud.s_peeo =3o0orpm?tator Vottage =2OkVStator Current _1o1g9AFrequency =SOHzPower Factor =o-g5wincting connectioncooun$-w-atl;ft& of srator winding ]Xrr^rrn,9!g!19 water pressure of stator winoing =o.idrvip"Fiefd CurrentFierd vortase :;8lf

/t l

:Lg\--Er

HF-.-1

'luiv)

tl$

ll Iil.T

x' (DXEra ?a

o:t

o5

6rE

a ai=uoeE

ne'J+-

: : ;_

tfg_6rid subsil

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RELAYS

The main furrction of a protective relay is to detect ancj to measure abnornralcondition & isolate the faufV section from the circuit by closing the contacts in thetripping circuit. The faulted signal achieved by cornparing two quantit ies either inamplitude or in phase.Signal relays function to register the operation of some relay by flag indicalion.According to the nature of actuating quantify to which the relay responds cunent,voltage. power. i:eactance, impedanrei frequenoy and direction change theyrespond to. Relay which respond to the actuating quantity when it exceed apredeternrined values are over relays and if they operate when the valueactuating quantity drops below a predetermined value they are known as underrelays

THE euRPo.sE oF FRoTEcrlYF FEU\ys MAY BE cl-AsstFt,Ep AS-

1, Cver current protection.2. Eann fault protecticn.3. Reverse po! ' /er prctection.. i . l i r ioer,;ci tag€ protection.5. Undei frequency protection.

THE DIFFERENT TYPES OF PROT CTIVE BEI-AYS ALONG WITH THEIROPERATIONS

1) Ovelcurren! [9laYs The operating time of all over current relays tends robecome asymptotic to a definite minimum value with increasing the vaf ue ofcurrent. This is inherent in electrornagnetic relays due to saturition of themagnetic circuit. So by varying the point of saturation diiferent char.acteristics areobtaineci these area) Defini:e rimeb) Inverse cjefinite mininrum lrnre.c) Very inverse Id) Extremely inverseThe torque of these refays are proportional to the flux produced by rhe soiheguan| i tyasincurrenlorvo| tageoperatedretay2) P-lre-ctlonal rglfl,yp= lt operates al high speed, witlr lrigh sensitrvity & lon vatueslvith adequate short time lhermal rating.

v

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33

Electricity distributionElectricity distribution is the final stage in the delivery (before retail) of elecfricity to endusers. Adistribution system's network carries electricity from the transmission system anddelivers it toconsumels. Typically, the network would include medium-voltage (less than 50 kV)power lines,electrical substations and pole-rlourted transforners, low-voltage (less than I kV)distributionwiring and sometimes electricity meters

Power Distribution at DPLUnlike many other places, a major incentive for any entrepreneur to set up industrialunits, toexpand existing units in Durgapur is the gteady and unintemrpted availability of power.DurgapurProjects Ltd is the sole supplier of polver (at I IKV) within Durgapur. It offers anattrastive powersupply package to industry:To maintain the qualrty of the product, stable power supply is one of the most importantingredients. The industrial units in Durgapur unlike many other industrial zones in thecountry,ertjoy this enviable power situation.Even the prospective investors can feel huppy and comfortable while considering newprojects inDurgapur industrial belt as DPL has surplus power and offers a number of incentives toset upunits there.

DPL assures:

Continuous availability of power

Quick response for Electricity connectionTariff concessions to all Industries (11 KV) link to Time-of-the Day (ToD) metering.Further incentives offered to new industries, industrial expansion projects andRehabilitation of sick units as approved by the regulatory Commission.

34

Transmission & Distribution

The transmission and distribution system of DPL with jurisdiction of an area of about 60sqkilometers includes the following :-a) 132 KV transmission line measuring 19 cirsuit kilometers served through three sub-stationsof 180 MVA oapacrty.b) 1l KV transmission/distribution line measuring 393 circuit kilometersc) LT distribution line network measuring 4250.5 circuit kilometers.

Distribution network configurations

Distribution networks are typically oftwo types, radial or interconnected. A radialnetwork leaves .the station and passes through the network area with no normal connection to hny othersupply.This is typical of long rural lines with isolated load areas. An interconnected network isgenerallyfound in more urban areas and will have multiple connections to other points of supply.Thesepoints of connection are normally open but allow various configurations by the operatingutilityby closing and opening switches. Operation of these switches may be by remote controlfrom acontrol centre or by a lineman. The benefit of the interconnected model is that in theevent ofafault or required maintenance a small area of network can be isolated and the remainderkept onsupplyWithin these networks there may be a mix of overhead line construction utilizingtraditional utilitypoles and wires and, increasingly, underground construction with cables and iqdoor orcabinetsubstations. HoweVer, underground distribution is significantly more expensive thanoverheadconstructiort. In part to reduce this cost, underground power lines are sometimes co-located withother irtility lines in what are called Common utitity ducts. Distribution feedersemanating from asubstation are generally controlled by a circuit breaker which will open when a fault isdetected.Automatic Circuit Reclosers may be installed to further segregate the feeder thusminimizing the

?{

impact of faults.Long feeders experience voltage drop requiring capacitors or voltage regulators to beinstalled.Characteristics of the supply given to customers are generally mandated by contractbetween thesupplier and custolner. Variables of the supply include' AC or DC - Virtually all public electricity supplies are AC today. Users of largeamounts ofDC power such as some glectric railways, telephone exchanges and industrial prooessessuch as aluminium smelting usually either operate their own or have adjacent dedicatedgenerating equipment, or use rectifiers to derive DC from the public AC supply.. Voltage, including tolerance (usually +10 or -15 percentage)' Frequency, commonly 50 & 60 Hz,l6.6Hzfor some railways and, in a few olderindustrial and mining locations, 25H2,'Phase configuration (single phase, polyphase including two phase and three phase)'Manimum demand (usually measured as thelargest amount ofpower delivered within al5 or 30 minute period during a billing period)' Load Factor, expressed as a ratio of average load to peak load over a period of time.Load factor indicates the degree of effective utilization of equipment (and capitalinvesfinent) of distribution line or system.. Power factor of connected load.

38

Location and Capacity of three l32lll KV Grid Sub-stations

l. - -".*-- -*- * ----..-,^..-*.--.-...-.-,-..,.-J, -, .**-- -*--i.

Location

iAvailability

jAdvantage

j

l

At the factory premises of flindustan Fertilizerl

3l ' txL+Lo+tu31.5 MVA

%I<M from G T Road and 3 KM fromDurgapur Railway Station

By the side of IWS MAMC

IjI

I'iI

iAvailability

iAdvantage

: l32KV/ II KVB-Zane

Jt'txf t JrzTt31.5 MVA

40 MVA

I KM from G T Road and 4 KM from iDurgapur Railway Station ii

i."','^"'.."".,..,*+ -----*j

To be constructed

lGrowth

: l32KV/l l KV C-Zone

By the side of IWS Durgapur Chemicals I: , . . , - __*- j

* *t , 3t't1 | ,2,?*4,tLf-xt i

Under process '/i

3 KM from G T Road and 3 KM fromDurgapur Railway Station

Under commissioning phase

4T

CONCLUSION

one of the blggest aclvanhges for DPL to serve its clier*s ls its production lacllifies belngloglstically linked wifi all the three major modes of transportafion. rall, roao and sea- Besides:Kolkata and Halctla ln the east, ports like vishakhapatnam, chennal In the south ancl MumhaiIn the west also handle DPL products. cutting across the states - from east to west and southto north- DPL is also gearing up to spread lts marketing wlngs abroad. The proposect ilst ofcountries includes srl Lanka, Bhutan, Dhaka and Quiton.

To ensure quality in every step of the procluct processing. DPL has a weil equlppedlaboratory haying sophisticated and computerized instruments such as GSR, CRi ,'Gaschromatograph, Spectro photometerEtc. Envlronmefit is a key concem to the DpL authortties.The Environment laboratory is equipped wlth bacteriologicaf testing klts, ambieril air qualitytestlng instrurnents, stack monitorlng instruments, gas anatlaers etc.

The sprawling township wift adequate lnfrastructure facillties speaks for Dpus concernfor its most valuable resources-lts employees. Besides adequate accommodation faciliiles. thecompany rulns a hospital and an educatonal instituflon to take eare of its emptoyees.

Evel. Yte_Prospective investors can Jeel happy and comfoftabte white conslderingnew projects in Durgapur industrial belt as DPL has surplus power and offers a number oflficentlves to set up units there.

DPL assures:'' Continuous availabillty of power'' Quick response for Electicity connection" Tariff concessions to alt Industies (1 I KV) l inkto Time-of-the Day (ToD) metering.' Further incentives offered to ney/ industries, industrial expansion projects and' Rehabil itauon of sicl( units as approvect by the regulatory commission_