CB STEP-UP

TR

!lUX. TR

BUS TIE

-0---1-

ISTATION USEJ

AUX. TR

CB STEP-UP

TR

GEN.!

HV BUS

IOFFICE USE I

, - 7+-1+-2 = STATION USE

-3+-4~5+-6" NET GENERATION

Fig - 3.2 A Typic<ll single 1i';(, cii8gr<1U1of " Power station showing tho definitions of net geJ1cl'Gtion nnd stntion usc

r---.,

3.15

ductor surfaces. Whenthe potential gradient at the =nductor surface reaches about 30kv per em (max.value)[15], an ionisation of the air surrounding the conductor results.

Whena voltage higher than the critical voltage is applied between two parallel polished wires, the glow' is quite even. After operation for a short time ,reddish beads or tufts form along the wire,while around the surface of the wire there is a bluish white glow. As corona phenomenonis initiated,a hissing noise ^1S heard and ozone gas is formed which can be detected by its characteristic odour. The phenomenon of violet =lour, hissing noise and production of ozone gas in an overhead transmission line is knO\olI1as corona.

Consider two conductors of radii r em and splCed d em apart. If v is the phase to neutral potential, then potential at the conductor surface is.

given by

v

g

=---

volts/em r In dlr

In order that corona is formed,the value of g must be made equal to the breakdo\olI1strength of air. The breakdo\olI1strength of air at 76 em pressure and temperature of 250Cis 30 kv/em (max.) or 21.2 kv/em (rms) and is denoted by g.. If ^Vc is the phase to neutral potential under these =ndi tions, then

Vc

g. =---

r In dlr

Therefore,critica1 disruptive voltage

Vc

=

gorIn d/r

The value of go is directly proportional to alr density. Thus the breakdO\olI1

•.. '

: , \

HLf"(~ru~Lhor air at 11hlT'olll{~Lr'il~prcssun~ of b em I)f' mercury 1Uld tenlperature of

to (; l}(:(:(mH~s5/gu

:1. !12 l>

c' __

o air dcnsi.ty factor' =---

27:1 + t Under standard conditi.ons, thr; ~.'alue of

6'=1

TheIT~T()n~ crj tical diR["1Jptiv(~ vo.ll..fJ.ge

f Vc = gobrLnd/r

CorTn~.~Lion must. l.lll-'O be 1I1{.uj(~[or" tJH.~surface corKli.Lionof conductor. The irf"(~gulari.Ly on the surface of" a conductor (hx~rea...scs its breakdown volt..a.ge.

'I1H~HUr,rf1l:(~condition or conductor.

r~~

^accowiLc.d ror by TIIuILi.pl.y.ing the above express.j on by irrel!uJarity factor mo •.

Thcn~f.'ol.c'-cr-.i.tj,cal d.isr.upLivc voll.(J..g(~

I

Vo = mIl go bTLn<!/r' IlvIphase --- (3.1)

010 = 1 for' IX)1 Lshcd eOl.fuetors

=

^{O.9H to O.!12 for <!ir'ty conductors}

= O. H7 to O. HO for: s ITand,,,f cOrKfuetors

It. hwt ^{ix;f'lI ~.lf~(~n}!.lial. ill l'a~H' 1)1' paf.nll"~1 c(mdU(;torH,UI(~ COf'OrUl Itl.ow does

flot bc~ill at Ul(: eLisrl.lpLj v(~ vo.!t..a~e v(: but at a higher voltage v.,called

visua.l cI'it.iC1iJ vol t.J11~(~.'I11e pha~{~ to neutral. effective value of visual criti- (:al. vol.lJ.lJ~c.iH given by the f()II{)wing emp(.~r.i.caJ.fOl1l1uJa:

I

v.

=

0I.g05r(l+O.3/~')llld/r kv/phase

where, ^Tilv .is anoLher il'['(~~ula['ity racL()r~havjn~ a value of 1 for polished con- ductOl'S and 0.72 to O. H2 for' !'oll)jh cOJ.I"c!.o!'".

3.7

Power Loss due to CorOlla

The ions produced uy the e.l.ecl.!';c l'ie.l.d 1'esu.l.ts in space charges which move round the conductor. The energy requirt.'<l for the charges to remain in mo-

Lion is derived from t.he supply sysl.P.m.Thus.fonnaLion of corona is always Be- complished by energy loss which is dissipated in the form of light.heat,sound and chemical action. Peek (15) made a number of experiments to study the ef- feet of various parameters on the ,corona loss and he deduced an emperical for- mula for power loss which is given by

v =

phase to nelJtn~J. voltage in kv (rm.q) Vc

=

disruptive vol u.II{e(rm.q) per phase where,

"(f+25)

p

=

^{241 x 10-5}

-6r-~

r!d(v-vc )2

f

=

supply frequency in 117.

kw/km/phase

i

.

, ,

\

.

. ,

I

3.8

Bider the aver.age air temper'aLurT~IUKJ preHHUJ,(~ be

cd tical di sruptive voll.a,ge (ntis). us; ng equation (3.1) is 171.63 kv is for a fair weather condition.

derived

the maximumoperating voltage i.n BPDBsystem is 132 kv. Con- equation

The

At present,

system.

respectively in Bangladesh.

The approximate '.'.'.}

. .

..

^~

loss. under foul weather conditi.on is obtained by taking Vc as 0.8 times the ...."

fair weather va~lJe. The emperical relation as derived by Peek has certain

"'1

limi Lations and gives results only if t.he supply frequency lies between ~5.. to.

120 Hz,the conductor radi.us is greater than 0.25 an and the ratio v/vc>1.8 •. '

"1

"'1

21° c and 74 em of Mg'"

t l

" .t

For 636 !'D'I conductor with spac;ing 182.88 em, the: \ (line

~::I!

)

line) . As the cri tical disJ"UpUve voltage is nnJCh.higher (1. 3 times) than the ~

i

. operating voltage.no corona Joss occurs at the present Bangladesh power,\'l

,

I

3.1.1.3 Substation Loss

Substation loss is the energy spent in the substation excluding that consumedby the control office. This loss occurs in transformers and auxil- Iaries of the substation. The substation loss is computedas follows:

Substation loss

=

Imported energy in the substation _ Exported energy from the substation _ Substation office use

3.1.1.4 Distribution Loss

Distribution loss ~s the energy wasted by the distribution system,including ;primary distribution lines, distribution transformers, and

the service drop to the individual consumers. In a distribution feeder,losses occur for the following reasons:

i) Line losses on phase conductors ii) Line ^losses on ground wires

iii) Transformer iron and copper losses iv) Excess losses due to poor power factor

v) Excess losses due to load characteristics

vi) Excess losses due to load imbalance on the phases

3.1.1.5 Transformer Loss General

As the magnetic flux alternates periodically, from a maximumvalue +Qm in one direction to a maximumvalue --Q. in the other direction, two components of power loss are developed in the iron core of transformer. They are (i) the Hysteresis Loss, which is purely magnetic and results because the tiny magnetic

1.( "

3.~

parLic]i:;s pr<x:Juc(-~a kind or m{)l(~cular' fr-ic.::tion llB they terKJ to change align-

mcnt, Hith Lhc r'apid n:vcn\al~; or alt(~r'"al.ill,g (;'urT(~IlL and -(jj) the Eddy Current LOSStwhj_(~h is (-~le<~l,r'om;lgn<~Li(~ill (~tl;lracter a.mij,g eUIJHed by, lhe flow of cur- rent,s i.n the i:d.m in exactly Lhe smite way as in the trtUlsformer windings. '!he alK)v,~ two cOIllp<m,.,ntsof Ix)wer losses vary wilh different exponents for flux dei,sily ami frcquency and d"I""d a Iso up<m the wave shape of the impressed voltage. Ina.smuch a.s ,till' flux through the core of a constant-voltage trans-

ronnel' J'(~tIlaillsnearly cOlIsL;uIL,the c()n~ loss detcI'Tri.ned at no load ^can be 83-

SUTlJt-rl W..; ~iconstanL loss over" the ^(~f1t.i.n~load range. With increased load the

flux .~.u~Luatty decreas(-~s hut t.he 1_(~alu.J..get.l1J~ :if1creu.c;es; Lhe variation is very snlfl.11 and Lhe el.T(,~-~Lsmore: or I(~SS neuLr"a]iZ("~.. rIlle- ~.L<:lHumptionof constancy is ,just:i f'iI~L

When th'e trans['omler supplies a load, the primary aJxi secondary currents

l)['{X.JIJC(~ "121l l.osses jll UH~i r' f"(~sp(~ctivf:: w.illd.ing-s. 'J11eHe losses are obviously variable with load. That .i.s why,it is call<.~i load loss or cu-Ioss. Note that Lh" copIK,r losses vary as U,o S'llla"O^0f' Lh", corr{,sp<mding primary and secon-

dary <=UTTeTILs and .this means,of' (~OUrH(-~, Ulat Lhey drop or ri.se sharply belowor

alx;v(~ th{~ rul] .l.oad,value h'h(~n UH~J.oud is, resJx~'ctively ,higher or lower than ["aLedKVA.For' example,wh<enI:.h" s(x:ond,u'y delivers a load. equal to one-half of raLc~dKVJ\tth(~coi-'Jx:~r :JOSS(~S hcc{)m(-~ orH-~-fourth of the fuJI loud eu-loss; at 1.5 LiJnes rat(~l I(VAt.!1"y Ix~,,)mo2 :2" Liinos as much

'l."

t.he full load copper losses.

Eddy cur:rcnt loss varif~s as UH~squaf'(~or t.he prrx.iuct of the flux. und UH-~ fn--~qtJcn<:y,alld l,y thos(~COlI:-;;tarlt factors wh~ich influence the resistance, vi""cortducLi vi Ly or Lh" :inm aJld the dimensions of the lam:i.nations. Thus the (~ddy ^curT{-~lIL .loss ¹⁸

3.10

where, J{e = proporL.i.onali.Ly constanL depending upon.

VOJUH}('~ of UH~c()n~, thich.rH~sgof the

]'aminaLions and regi'sLiviLy of steel.

13m = maximum [lux d(~m...>.i.ty in cor-e I' = frequency

The presence 01:'hysLersis losses in a transformer. core causes the

pr,'.IIWu'y to t.a].u~ current. which ha.'4a. c()mpor)(~nt. in phase with the impressed voIIJ.lge. '111eeffecL is 8iOl.i.lar 1.0 thaI. produced by (~jdy currents •• 1'he loss is a function 01' Lhe arca 01' tlte hysLeresis loop 01' the transformer core. The hYHb~reHiHloss can be. (,~xJH'(::sscd.by Sl.ei.nmetz'~ emlx.::riea.l equa.tion ;

where, Kb ="y\. v

=prol'ort.i.onaj.i. Ly cons Ulllt depending upon

. VO.!Ul"" arKl qual.i.ty of ^HLecl.

1'L

= SLc.i.nlll(eL",cocfLicient-.

r ::: rn~(l'l('~rH:Y

TIm::: r-t:lx'illn.nn flll:'< ('J(~nsit.y i.n (:()n.~.

'1.11(~ induc(~]emf." in .t.rnnsfOI1I1(~r'.coil. . .is E = 4. 411"1'1cp",x^{10- 8} vo.! ts •

,.,rhere, N::: Number of tur'ns in coil

<J)rn::: Ma.x:i.nn.nn

r

lux.

3.11

E x J(J"

:md

4.44

r

^'N

10" E ll"

= (-~---)--

4.44 N 1\

r

where, A

=

^{Area of core}

For a given tr-dIlsfoI1TlCr,Nalld 1\'al'e consLant; therefore the terms in the bnlcket may be set equa.l to some constant K. Thus

E Urn

=

k

f

SUbHL.iLuting Ud~. vallJ(~ or flux d(~nBi,l.yHI IJH~foregoing core-JoHs' equations gives

E7.

p~= K., ^{[2 K2} (---) = K2 E2 1'2.

El. ⁶ -EI.6

Ilnd Ph = Kh f ^{K', G} (---) = K

, (---)

ft.6 1.'0.⁶

where,K. (Hid K2 are sjlllPl.y PI'oJX)I'Licmalj ty constants. Si.nce" the totul core Joss Pc is the sum of the hysteresis and eddy CUI'I'ent Losses,it foLLows tiJat

HI. ^fi

.1'0.6

It is esp:,c:iaJly imJxH'\;H1tto not" that for a given impressed vorlage E, Ul(~ (~:J<]y current ^.IOSg is ⁱIJ(J(_~r)(~rui(~r,L ()[ the frequency thi.s Loss .i~lhow{~ver'Jd.i.rectJy pn)I)()T'Li()flal t.o-the Hquan~of ^Lh(~impressc--demf. The hys- tel'esis .loss does ,⁰¹¹ U"e oU",1' Im,,,J,depend IJlxmboth the appLied voLtage' and it,s 1"re<luen(:y.

'nIl'

following 1;",.1" ,;!Iowstypical Josses ^1.1:1) for some three phase power

3.12

transformer operated at rated voltage expressed as no load and load. The losses at 75°c are as follows :

Table 3.1 :Loss data for Three-Phase Power Transformer

(Rated capacity 10/16 to 63/100 MVAand HVratings from 72.5 KVto 145 KVwith on-load tap-changer )

---

Rated =IJllCi,ty at ONAN0NAF10NAF2

(MVA)(MVA)(MVA)

No-Load Loss

(KW)

Load-Loss at

ONAN00AF1 00AF2 (KW) (KW) (KW) ---

10 12.5 16 12 40 65 102

12.5 16 20 14 46 75 117

16 20 25 16 55 86 135

20 25 31.5 19 64 100 158

25 31.5 40 23 72 115 184

31.5 40 50 30 82 135 210

40 50 63 37 93 145 234

50 63 80 44 102 161 262

63 80 100 52 119 192 300

---

Whena transformer is operating at rated load and voltage , the load loss and no-load loss can be easily determined. Occasionally,it is necessary to es- timate these losses when the transformer is operating above or below rated load and voltage. To determine approximately the losses when operating other than rated voltage,the losses at rated voltage should be multiplied by the

factors given in the following table [16];

Table 3.2 D.ist.ri!Jll!,loli transformer: Josses at olher

\

t.han. nl.L(~,J v()lLag(~

voltcuge Loss Loss

X. rated No-load Load loss vol tage Loss Loss

80

81 82 83

84

8f;

87 88 89 90 91

!!2

!!3

!14

!!7

!!8

0.61 0.62 0.64

0.67

o

^.6!1

0.71 0.72 0.74 0.76 0.77 0.7!!

0.81 0.8:t 0.85 0.88 O. !IO

0.!!2 0.!!5 0.!!8

1.56 1.52 1.47 .1".45 1. 41 I. :17 1.36 1.32 1.28 1.25 1.24 I. 21 I. 18 1.15 I • 1:1 1.11 1. O!!

1.07 1.04

1. 02

100

101

102 lO:!

104 105 106 107 108 10!l 110 III 112 113 114 115

lJ7 118 120

3.14

1.00 1.03 1.06 1.08 1.12 I. 15 1. 18 1.21 1.25 1.28 1.32 1.36 1.3!!

1.44 1.48 1.52 1.56 1.60 1.65 1.74

1.00 O. !l8 0.96 0.!!4 0.!!3

O.!lJ 0.89 0.88 0.86 0.84 0.83 0.81 0.80 0.79 0.77 0.76 0.75 0.73 0.72 0.70

Wh(!fln trans l'o Tl1Jcr . ()TX~nl L(~sother thilTi ra t(:~dJ^{oad, no J.Oi.uJ} I.()HH remains

COIlB t..Jlllt ut fulJ. J.<)(ldva IU(~.1.':\ (IjSCIJ~,S(~J(.~arJjer but Ul(~ load Joss v(lries as

follows :

'II 0 OJd

Load Loss = ( )2 X Load loss at f'aLed load I,.^{ate d}

KVh oad KVratcd

= (

^{)2 X ( )2 X} I~ad loss at rated load

KVA,.alt!d KVload

Table .1.:J i.s a Sl.UTnnaryof the J^(~SS(~Hfor some transformers at~ variou..q load levels

Table :1.:1 :DlsLrlbution Lran"roIlller' No .load

and load losses versus varioUs load ,levels.

TI1111s:l'onner No .load Lotlll I.osses

(RW)

at various load

.si~e loss levd.s

(KVA)

(RW)

50% 100% 150% 200% ~50%

5 0.lH5 0.0:17

o

.1!\1 0.323 0.572 0.8!J:l 10 0.070 O.OGO 0.237 0.532 0.941 1.473 25 0.2:10 0.118 0.167 1.018 1.860 2.903 50 0.225 0.204 0.808 1.814 '3.222 5.030 100 0.100 0.375 1.191 3.318 5.945 9.283 250 0.925 0.781 3.105 6.!J72 12.383 19.336 ---

The empirical relationship [6] between load factor and loss factor at the distribution transformer is given by

Loss Factor

=

O.15(Load Factor) + O.85(Load Factor)2 and for the grid transformers,the loss factor is given by

Loss Factor

=

O.30(Load Factor) + O.70(Load Factor)2

It should be noted that the load factor refered to in the above expressions is the load factor at the transformer,and not the system load factor. The energy losses are derived from the following equations :

No Load Loss(KWH)

=

No Load Loss (KW)x no. of hours

Load 10ss(KWH)= Peak Load 10ss(KW)x no. of hours x Loss factor

Therefore.to~~ energy loss of a tr~former for a particular period ~s giv('J}by

Energy loss(KWH)

=

No Load loss(J{W)x no. of hours

+ Peak Load loss(J{W)x no. of hours x Loss factor

Sample Calculations of Transformer Loss

Based on the above discussions , losses of some sample transformers now in operation in BPDBsystem have been calculated. The peak danan<i,input/output energy and operation time have been obtained from the log sheets recorded at power stations and sub-stations. First, the load factor and the loss factor were calculated and then the iron loss and the copper loss were calculated.

Data available for iron and copper losses per transformer capacity have been

- -...,~..:.- ~, "'4-& •• '"-•.; ••>.•.••i.)••..,~-'.

. . ..•, .1

lJH(-:~d. Bul. wtH.~U dut.a waH not avai Illhle. t.ypic:aJ dalJ!. aVI1..i.lllble in IIVulufacturera

cut"lOgUCRhave lx~enu'l(~L 1\ calcul.ation Rheet us given in Table 3.4 have been URedto show the detail ^arx! step by step calculation of transfonner losses.

The .I.0'lR resul t for ROil", salllp.!e HLep-up tn.lJLqfonners and grid sub-station tram;fonners are given in Tabl.e 3.5 ,.UXJ 3.6. Xn a similar manner, losses for all trdlisformers can be obl~lined.

on,e reHult of the analysis is sUlIllll(~risedin the following table

I•

I

•

Item

FY

1985-86 FY 1986-87

~I

"

Power Energy Power Energy Table - 3.7: Losses in % of net generation

---~---

---

• Step-up transformer Grid substation

0.38 0.34 0.37 0.34

.

^' .

.

~

,

transf onner 0.35 0.40 _0.38

--- ---

Dielectric Loss 3.1.1.6

IIIhen voltage is applied between two plates seperated by

nUlllberof free electrons is

dielectric, the few free electrons that are present

from cuthod to B1"xic. This is b,,,ned a cond\lclion/lealu~e current ( from anode

Most of Il,e energy which flows into the insulation in the high.

is

I

in the insulation drift ,-"'

J !

to cathode ) and represents power loss into the insulation. In insulation, •the: . \

.

\

. ^,

low,and us a result the resistivity of'

ther'.

_!,

• ,

,

material

fonn of charging current is returned to the system as the voltage alternates.

However, some is lost in the fonn of heat. This heat loss is known as the'.

\

3.17

Table_";!'~jTre.nst'ormer Loss Ca.tculation Sheet llt _ SIS in FY__

,.' t~IW)

tKW)

(IKWH I (;1 VA )

(HRS)

(A)

(C)

TOTAL IET=£I+EC) tX)=ET/DtiOO COPPER (H)

;PEAK DEMAND (B) :OUTAGE TIME : CAPACITY

: COPPER IDC)

: = H'(B/A'pf)tt2 (KW)

:---~--- ----:

TOTAL Irr'Ol+or:) : IKW) :

IX)=!. r/BtlOU ; (X) :

' ,

.---,

: ENERGY : IRON lEI) :

: = DIt(8760-C) ,

: - - - ---- - - --- -- - - - -- -- ..._-- -- .-- - ---"~=--- - ~

: COPPER (EC) : :

: = CCt(~7oU-C)*G : :

:---~--- ---:

,,

,

,

,,

:---

,,

:---~---

--- ,,

:---~._--- ---

:---

---~---

.:LOAD FACTOR (F=D/(H7ijO.c)ltB) : •

:---~--- ---:

:LOSS FACTOR (G=atF+tl-a)tFtF).: •

:---

LOSS :CALCULATION

:TRANSFORMER :ENERGY DESPATCH IDl

:LC.~S---- _

: I RO:i (I ): (KW)

:=========================================================================;======

: :DEMAND : IHON IflI=I) tKW)

:---~--- ----

:=====.===============================================

=======================~====:

:. MONTH ENERGY DESPATCH (KWH) :OUTAGE TIME (ImS): PEAK DEMAND (MW) :

---

---~-:

JUL : t

AUG :

SEP :

OCT :

NOV :

DEC :

JAN :

FEB :

MAR :

APR MAY

JUN

.---~---~---~----

; REMARKS

,

,

'---,

: TOTAL ; I KWHI I HRS) : I MWI :

:==========================================================================;=====:

==========================~=========================================~======~=~==

3.18

r

Table - 3.9(a) :Transformer .Loss Calculation in FY 1?8S-S6 Ge~efator Step-up Transfcrmers

Total loss

POl4Er Ef:ergl'

(K~J) (%} (H\m) (:)

Copper Loss PUler energy POl';2:' Ene!"'})'

(KW) {/1UH) (r.~n (H~!H)

Iron loss

---

--- --- ---

Name Transformer Despatch Outage Peak load loss Losses (nil

of Cap. Energy Time DE'Qano Factor Factor

Staton ^{(HVA) (H~IH) (Hours) (HU) (PU}} \PU) _{iron. C'jPPf'f}

Ashl!ganj (GT- 1) 76 289575.D3 2175 57 D.771 D.647 28 23D ^2f; 184.38 159.72 63B.741 187.72 0.33 823.12! D ,,',_{.• 0} Ashuganj (uT-2) 78.5 9413:.75 6144 60 0.60 0.462 .37 290 37 96.79 209.16 252.784 246.!6 0.41 349.57~ 0.37

Ashuganj (sT) 47 51055 6941 35 0.802 0.6908 22 180 22 40.02 123.23 154.21 145.23 0.41 194.23 0.38

---

T-~t,l~ ~.;(t.) -T!.ansformer LClss Caleui-3tictfl in r'- ~';26-B7

GenErator Step-up Transformers

t)-J;1i?

01

Stlltic'r1

Transformer Despat.:h (Iii t\J90 PEa~_ Load Loss LyS52S (t:W) iron L0SS C;:,pper Less Cap. Energy . Time ^Demand FactOr- Factor

(NVA) (HWH) (Hours) (HW) (PU) (PU) Iron Copper rGiJer Energy , POi~et- Energy

U:i!) (r.!-!F: (fiJi (HWH)

Total L0S~

P('ti~fr Energy (KW) (r) (~~JH) (.i)

---

AS,hugan j (GT -]) ^{, 76} 25'i11l.7' ^'),LO,)"

...•

.,. "0r:;'-, 0.754 0.624 28 230 ^'),.. 165.'6 165.3::; 607.695 193.38 0.33 773.655 0.30

"'

t\shuganj (GT-2) 78.5 243922.17 2289 S4 0.698 0.5504 ~\/~, 2')0 ";,," ^239.427 169. 4~ &06.278 206.42 0.38 845.70 0.35

_Asnuganj (ST! ^p 101522 S065 34 0.808 0.70 22 180 22 Sl.?? !!6.29 300.7i 138,2::t 0.41 382.D6 0.38

"'

3.19

,

^:

-.:_---_._-' ----~--

,_._---_._---'---'---'----'---~---~~---'-~-~---_ •._---_.- .---

Table - 3.'Lli :fransfoner los~ CalclJ1at!on in rr 1:9S-26 IJUJj rv rrJn:;!cr;~I~

lo:al less IJue

of

~tJ~kn

fransfor,er Despatch Cap. Energy (~'1'" (/H:!!)

Outage Time (Hr;ursl

leak

~~m.1.,J ,~,:,.:11

loa,j Fat h1t

l~:J~

loss Factor (Ful

lossesil~)

;n~C,);,pr

IrM lo-:;s

?,:a;-r E.~'~:.;or {WI U:w~l

CCPPH lilss

FC!1~r £nH'i1 ([~l i~HI

F,m~r

{uo (:) ii:~!!;^f:l~r'~.,L~j

...__ ._--_._ _--- -- --- - _ -._ _..- --_ , --_.__ .

:!!sna~ad fl 5S 165699.235 11 ~j C.S7j 0..1028 j~.'ll 163.7 j.l..n jOS.f; Ji.?~ 2~1.2~ 101.81 O.Ii S61.G] o.^j~

ihsnaba1 It 55 165697.235 !~ 33 0.5:': 0.1028 .il:?! 168.: 3'1.91 jIJS.:.'S J4:]3 2~LCg5 109.;19 O.:J 5;:.3j5 0.:4 ':leuHi:;;ur H SO

lIeu llirpur 12 50

152500 146565

28.;

IOU 43

35.5

O.iO& 0.237 37

o.m ^{0.3024 3:}

).15

145 31 31

323.053 132.4 27J.98 320.33 90.2~ 236.Z5

169.~ O.;? 59].1)38 141.21 0.36 556.59

0.j9 0.3g To"gi U

ron9i 12

H.l 15

JjU]9 180180

13 13

2J.a 31.5

0.:07 0.562 27.5 100 0.6S~ 0.J~56 53.2 HS.Z

27.5 2~O.5~ 33.74 165.56 59.2 509.0]5 96.95 ~20.2a

61.2~ 0.29 106.1 155.IS 0.49 n~.jSS

0.00 0.52

r'J!si II 63 93390 2~2 26 o.m 0.2513 ~~ 161

••

^{37~.n2 33.85 12.~6 77.9S 0.30 l~i.~5 O.lS}

lulsi n 6J 98160 _II' 26 ^O.H 0.2615 " ¹⁶¹

••

^{3CO.~Z' 33.:J5 78.29 77.SS 0.30 -i~.it O.~i}

Table Hfcbl :Transformer loss Calculation in FY 11S6.~]

jj2/33 IV rr~nsforilers

Pellu Energy POller Enugy (1'1 (H1IHI (1'1 (1ilIH1

~a:e of Station

TransferRer ~!Spatch Cap. Energy

IMYI) IIl1IHI

OutJge Tiile CHoursl

Peak lo.!d oe.and Factor OM . (lUI

Loss Factor (lUI

losses (rW) Iron Copper

Iron loss Copper loss Total loss POller Energy

I(WI UJ (:l1IHI III

... _ _ -

..

~ _ _

~_

^{_ -}

.. _

^~

^..

^{_ _ _ _ _ __ __}

^{_-_ _._}

^{_ _ _ ~_.}

Hasnabadit

Hasnabad 12 55 55

152193 152198

US 3.5

;So

;S

O.~S7 0.tsJ3 j4.n 168.7 O.lSl 0.2BJl lUI 163.l

3'(91 30S.6~ 91.42 2J6.6 R9I 305.64 99.U 246.6

134.33 O.lS 552.N IlU3 0.35 552.24

0.36 0.3G :lell Hirpur 11 50

nell Hirpur 12 50

151110 146009

65.5 2Ull

46 41

0.l78 0.213 J) 0.~0i9 0.2388 '37

145 145

J) l7

321.69 151.52 280.60 m.06 120.l7 25i1.?11

188.52 0.41 602.1'J IS7.3. 0.39 574.01

O.~O 0.39

Jongj II U.I 131104 32.8 0.15~ O.ZSS ~7:S 100 27.5 ZiO.84 ]6.39 190.65 10.1.88 0.32 431.1:) 0.j3

Tongi 12 15 Illi60 43.6 O.H? 0.276 58.2 445.2' 58.2 5O~.l.71 ISS.;5 H? 243.95 0.56 958.11 0.56

fnlc:j 11 lFJ'lsi 12

63 .63

106161

!J?5.~0 I'S7 52

32.5 50

0.18 0.21

0.305l U 0.1l2 ••

161 161

u u

~.3:1 52.9 IOS.81 j8j.15 125.2 H3.n

96.9 0.00 1Jr.l.Z 169.2 O.3J ~m.:l6

0.18 O.is

.'.~

^-

3.20

It.1 ~

r ,'. . ( . ',' •

~.

:"::-""'t_,l~ .~; •••;..~.•...

....;..;.t_~..•••...,;,.~•....-&:e>' ., •..:t....

bY••..

. .,.^~Z-~~. .•^{••"b '.:..'} t. ^.<'i~...•..•.^..•••,;;....^' ._.)-.•^{~- p.., If. .'}

"

d iel,.x::I .•.ie lOBs. ^~,.•.

•

Cable i", a sorL oj' capaciLoJ' wiLh Lhe core and the sheath Lwo plaLc", of Lhe condcnser scpcraLe'<1 by c..IielccLric maLerial. The

I,

'f

fonning. the

,I

equivalent

.:.1

ci,ecuiL fur this reslHI.aJlce H and a

"' sYHLelllis '-"pf'esenLe'<1by ^l.l parallel combination of lealmg';' "

. ^. .

^'

.

^'('

capac;,!."nec C. 111e equj valent eireui t with i La pbasqr'.

..

d.i,/.tgI7l1n;s given ill fig. 3.3 . The JOSH irr Lhe dieh,e!.ric is due to the loss in'"

,.,.' '4 ,

r---

1~

1

t,

,'.

, ,

,','

",~c.

v R

Lhc cqu.;vaLcrrL leakl.tgc

",,,i

^{s Lmll;e.}

P

=

^V2/R

Fr"om pha ..<.RlJ'dj l~n1JlI,

,

••• "

• t ;., "t'

.f ~

, '

l " "'-f

~ t... .••._.•.:...•

,

..

" •...

.•.

..~

^.",,'

• t

"

^t

I

I

I I I

I

"IR ^{V ..~~'}

Equivalent circuit'

. .

I

--- (~

VIR