Barzam A.B. Automation in Electrical Power Systems (Системная автоматика)

The

circuit

used

lor

calculations

is

similar

to

that

shown

in

Fig.

g-Ab.

In

thecaseofaone-endsupply,thecircuithasihofo'*shovainFig.=9-4c'

.!

The

equatious

det-ermining

whether

the

rt"it'"t-*i;i;;"-it

isusuitable

for

tne prupose

can

.be

obtained

anaiJtically.

Since

the

set

of eguation-< (g-Z)

is

Fig.

H.

Eguivalent

circuit

n'ith

one

open-circuited

pbase

'

(a)

circult

diagram; (b)

equivalent

circui!,

.

general

lcase;

1"1

eguiva)ent

circuit

s.ben

line is

supplied

-at

one

'end

colnmon

to

any

aslmmetric

operation,

\f,,e

assume

that .bry

:

ir.r,,

:

En.ph

and

then,

after

subtracting

expression'(g-7b)

and

then

1s-'zly

troil'is_z[,"i,}

obtain

ONE-PEASE

AU?OMATIC

RECLOSURE

After

solving

(9-13b)

and

(g-ib)

and

eriminating

ro,.

we

obrain

h'.os1Lzr*

Xzo)

-

i,etl2z12z2f

XzlXaof

{I,2222fl:

io,

[Xa11

Ee,

*

Ezo)

f

Xa2Xze]

bn.pn:i

Is- '

xze>z5l

'ftL"rt

-

T;5o-_1

(9-16)

*--P:1-!!9

eguivalent

impedance

of

the

eguivalent

circuit

inciudes

the

for-

ward-seguence

imptdqlqg

reduced

to

the

open-circuit,

poiut,

whicu

is

series-

connected

r,o

the

parailel

connecred

backwaidr

;d

;;rJ-;fi;Lo"i'i-p*dances.

cascodt

disconnec.tian.of

phase

at

earth

!a.ult.

To

anal yse

the

operation

of

the

prot.ective

relaflng

and

discrimiouiing'"d-"ot*-oi

F,ARI

iioiii;'it

is

importa.ut

ro

know

hon,

the

6

nX,

N

Fig.

9-5.

one'side

tripping_of

fgul.tv

q!"rg

in

the

pARc

cycre

during

one-phase

short

circuit

of

pbase

,4

(o)

clrcult

diagram

(figures-J,

2

and,

0

correolrond

-to,forward,

backward

and zero

seguences);

(D)

equivarent

circuir:"(c-'l

roFard:,

uil'riili'a-,

:igl"il*ipEititi.",rit"

lshown-in

biiit

eurrent

and

voltaee

values

vary

during.casclde

o-ne-side

tripping.

of

tle

faulty

phase

at

the

:yfj]-v,

ll{-:l.F;t-r,angniqion-ti"".iFie.

9-s)-;r;;"ii"r'on"r.

r is

rrisnanh6^{dr

r-^*

eL-

DruE

ur

,,u,sLatlotr

tvr'

en the

.ff

substation

side

all

the

three

ph"d;;;;"-lii#Iila]""

CEAPTER

NINE

303

and

hn.pn:

ittl"r-

ior2r,

bn.pn:

I:.rI,rr-_

iol,ro

In compliance

wirh

(g-l1)

i

nr:

-

(i^,

*

io)

y

De

presented

as

(9-t3a\

(e-{3b)

(e-r4)

(s-{5)

+

-

k

i-+

|

'taz

I

i

n.

pn

:

i

nrLrr*

(/a

r +

/r) 22,

:

i

n,

1.2r,

+

Ezz)

*

i

o1r"

CII{PTEN

NINE

ONE-PIIASE

AUTOIT{,ATIC

RECLOSURE

305

we

assume

a three-phase

system

where,

in

addition

to

the emf.

ioy,

tbe

emf

uo,

applied

across the

break

m

-

n and

the

voltage

ri:.."t

thl

short-circuit

point

act.

The

joint

effect

of the

eruf

and

voltages

is

such

that'the"conditioni

foi"ur".ot

aistiiuuiion

rroog

the

phases

of

the three-phase

circuit,

rvhich

"re

cuaiacierirti"

or

il*

"ry**etrjc

operation

under

con-

sideratioa,

are

satisfied.

These

conditions

are

[9-BJ.

(a)

No

current

fiqws

in

the

faulty

phase

i|t"

-

0

at

the

point

of

open

circuit.

(b)

l4lith

a

lateral

at

sbort

circuit,

no

eurrent

flows

ia the

sound phases

ir;

-

ig

:

o

and

the-

faulty

phase

carries

i;:

i!.

(c)

since

no

eenel.ltjon

is suppl!.ed

-irop

the

substation

f

and

the

neutral

conductor

of

the

rransformer

of-substarion

ris

i,iriuea,

ih"

;;;;;;;';;qril;

;[;;;_;&uence

curreDr

fiows

in

ail

phiset

tbrough

thil;;i"r

r

r;to

tu.'piiot

of

shorr.eircuir

l

if,*

:

ifl"

:

i

5'".

il'":/f''":

o

(d)

The

faulty phase

voltage

at the

point

of

one-rhase

short e.ir.n-*ir ic zoy.n

.ri*

-*

,l

From

the

calculation

d-iagrJms

of tte

.uprr"ro-"*1"*"-

"r"";,;;'"1.i,-,""""

"o

:

u'

"a"n"es--ir-i;:-9.-;;

thougb

e)

it

ir r.!",'th;;

oceuc'des

oi

cuffeiils'

voiiages

anti

imp-

,

since

i'fn:

i

Tn

aDo

u'irh

(9-25)

raken

inro

Frora

Fig.

g-Se

it

(Fig.

9-5c)

i"fo:r'gi

1rig.

o_say

account.

expression

(g-24)

may

be

translormed

as

foilou,s

i'o':

-zi;n

(9_26)

is

seen

that

i

(e-27)

'

qs-zs;

(s-2e)

\ltith

account

of

-

u8c:

if;"';"

(9-20),

we

find

-Li6':(ji'-r

3")"f'".

After

substiLuting

the

value

of

tfc

from (g_2g)

i.nto

expression (g_23),

we

have

since

_

L'3.

:

i

oorrt,,

_(i

i.

_

rr

f;rr;

,;..

r3':ti:.:iT^

from

Fig.

9-5d

from

Fig.

9-5e

7'Gsc _

'

!A-

ITe:

Ii';-

f

G*

-

'2'_*I?t1:I|en

)sc_7oc, 7.Fsc

0

_:"0

_.t_iO

.

/

i.:

i

f,.+rf*

I\iith

closed

electrical

circuits

the

sum

of

the

emJ

and

voltage

drops

is

zero,

from

Fig.

9-5c

E

ta

-

UI'o

-

u'f-a.

:

ilor?

u

rloc r';sc

',

-u

2A-

u

zA:

t

fi2f",

-

cifi.-

u;.:

i

"o.rt*

i1'o+iTn+iff:o

i\

:

-ti

Tn4iffn1:o

es

ffi

-

i5

:

o

ir

follows,

rhat

sioce,

accortiing

to

tire

condition

characteristic

oI

the

asymmetry

under

consideration

l1:o

i

3*:rB':-2rii:

*ziTo

.''

-utr:

-ziTerS*_

rr

1"e*2i

il*)

,d*"

-

u";

:

-

2i

l'a"8*

-

slforf'.

Adding

the

riglrt

ald

left

sides

of

expressions

(g-21),

(g-22\

and (g-28),

.and

taking

inro

account,

that

ulc

:

0.

i-e.,

ti;i

+

uto+

u5'

:'o

"oa

ar

the point

of open

circujt,

{ir;:

:

Uo;

:

0

and

U\',q,

:

Ui"o

Ju6.,

i*,

obr,arn

i

ro

-

3uff

:

i

|,^r?u

+

i

y^

rfu+

I

B.rf,.

l\rith

(g-80)

taken

inro

account

i,o-euy:

i

1,o,f',

+

iTnrt*

-zi

T^zt*

i

ro-

3U3'

:

i

I'n

G?'"

+

,l',1

-Ziy^rf,,

substituting

the

varue

of

{c

from (g-31)

into

this

expression,

$,s

hrr.

t

ro_-

oi

l,orfu

-si

TAz[",

:

i

Ie

k?o

*

,?;,)

_

zil,org*

hence

Eu.:

to:il"n

ef'"

+"t""

+

(e-l

i)

(ri_18)

(9-1.9)

(e-20)

therefore:

tQ-r 4 \

(e-22)

(9_23)

(e-24)

and

(s-30)

(e-3{)

(s-32)

then

t.

e.

IT

---F

i1n:i#:i

i.

(e.25)

20--2076

i7"n:i";:

(e-33)

306

CEI.APTER

NINE

ONE.PHASE

AUTOMATIC

NECLOSURE

The

zero-segueDce

current

frowing

from

the

substation

M.

ifl'":

jf;'":if':

-

u\"o

aud

in

compliance

with

(g-g3)

j

Y*: =

2i"

-ffi

The zero-sequence

current

flowing from

the

substation

.F

if,"::

i

i"-itr

and

with

(9-33)

and (g-94)

taken

into

account

2r'

f.FsC

aLA

ro:"fffi

It

is

seen

from

the

above

exDressions

that.

q,hen

c.ase.edp trinnino nf an oorrho"r nl,^.^

is

used,-rhe

zero-sequence

"ur.eofJf}oodns

i" lb;

ji"elrF;";'fh;"",,'f,r;'ir"'I"'ii'"Ii-iy

are

far

riifferent

in

vaiue

from

tbe

ru.r.ot.-tio*irg

t" ir,"

on.-p'n-"r.'ruii;i;i?ffi;"

,i*

Ti"i

rlr''rf

when

the

faulty

phase

of

the

line

is

"oor"Ctr?

f;om

both the

substatjon

M

and

subst,a-

tion

.4,'

sides.

To

consider

tbe

effect

of

the

load

on

tbe current

flos,s

in the

phases

and

on their

sym-

metric

components,

the-

impedance.

,f"

and,

z{"'

and

tbe

c.orresponding

ioad

impedances

shouid

be

piaced

into

the

eguivalent

circuits.

T-his

done,

tbe current

calculations

are

made

.a'ith

due

cbnsideration

to

iEe-p;;ii"dm

i""iur".

oi tii"

tp."rti""

[,Ji"g-"-""rJized.

The

cai-

culation

technigues

are

dealt

wii,h

in speciai.literature't9-sj.

9-2.

Tyae-s

of Discriminating

Erements

of

pARC

Devices

at

fault'

when

two

or

three

voltage.

relays

function

siuaultaneously,

this

mav

be

the

case

when

tyo

p["*.

ui,

"irtni&;;;""

the

case

of

a

rhree_phase

shori

.'li:?l!

iil

JJ';:1,:'"11

**,fi::

:#i"'.f

"

il

I'u,

n

o *,

"i

"

v,

-

J

-i

h-e

a

e

v

i

ce

s

o

tripped.

carr]'

the

current

B/o

and

the

voltage

coils

to

tlie

voitagej

of phases"A,

B

and

C

The

relay

contacts

are

con_

nected

so

that

f.he rr",.,+o.+l..j

l-],

int,endpd +^'-l.t-lLf^:i""1tt

slreult

;

_

__:

4vr

ur

rlr1.lru5

r,le

DIeakeI

Of

pbase

A

is

compleied

throueh

the

tripping

bontacr

oi

th,

,.friro"?cted

to

voitage

[/oo.

phase

I

is.

compieted

through

the

closing

r.oltage

i,'ao

arrcJ

the

breaking

contacls

Fig'

g-7'

ttl:"il

of

faulted

p'ase

discriminaror

.$,itn

power

reray

(o)

circuit

ciiagram;

(b)

diagram

or

*ljlif;tt;;i#Fr""r.",,

,"

earrrred;

retay

p.R

307

(s34)

(s.35)

Flg.

9-6.

Circuit

of

faulted

nhq"o utic^-;*..

nator

*,ith

undervoltffe*iilii""".",-

the

voltage

Uc,o

and

through

the

make

contact

of

the

relay

connected

to

the

The

circuit

tripping

the

lrr"i..,

of

contacts

of

the

relav

c.onnected

to

the

'i:AJ

-

*lL"suLsrion

{fiq:€4-\44en

{

ene-phaseifi"rt

-1"*:+-""o..

or t}eiiae;

thC tqrrff rv nhoca

"^l+^-^

.I-^ J i't- - r. r .

;L-^::.T^"r^_::1:u.v\rrL(fBri.."l.rp"

auu

L.oe vorlage

rela\r

connected to

tnls

pnase

T+ io ^i^* ;-:9

","'*yreus

Lrr-t'

orrcul

^\

ro

Devl

1rurrr

[ne

vgctor

diagram

fiillil^ll

phase.,4,

.the

"*..it'

sr.

vIil

Lr

r-eray

rs

retrably

braked

n,ith

closes

its

contact

to perhit

the

protection

system

to

trip the

breaker

of

the

frhai

t

tor

trippine

the hnoor,o- ^r *L ^_^ ^

(e-lb)

tt,t

fr.,

rh;

;;;;;'r

Toflffl.*!

rlort

makes

t,he

first

rplo.=, +,,-.-=-r--

tl

the

e

ff

e

ci

c;;

;il;;i,;',il

";i,"#

;r;"j:?#:

308

CI{.A,PTER NINE

the faulty

phase.

It

is easilv

seen that

in

the case of short

circuits on

the

other

phases,

the discriminating

elemeut

operates

simiiarly.

At

the receiving

substations

the

potential

transformers are

generally instal-

led at

the

low-teasion side

of the

power

transformer. The

discriminating

ele-

rnents

with

power

relays make

it

possibie

for them

to be supplied

from

the

voltage

transformers instalied at

the

delta-connection

side of

the

power

trans-

former

which

uses an earthed neutral

star-to-delta connection. Account

is taken

of

the fact

that

a

certain

interphase

voltage

of

the

delta

side corresponds

to a cer-

tain

phase

voltage

at the star

side.

For

example, interphase

voltages

(-U"'o,),

From

protectibn

Cl

os

tng

.ol-

a

-ur_il

t

g7y

relevs-

ARA,ARts.lEt'

froni

cuteni

stariint

ARA-/ AR8.2

3r_

Lt

A.

T

c-

(")

Fig. 9-8. Circuit of

phase

discriminator

u'ith

power

relal,

of

cosine

t-vpe

u'hen

the

vottage

coils are-suppiied from

the

delta side of

tire

power

-transformer

with

star-connected s'indings

and

deita-connected

neutral

point

(o)

circuit

diagram;

(D)

<iiagrams of currents and

voltages

(-U

o,r,)

and

GA

".r,)

at

the

delta

side

of

the

power transformer

correspond

to the

phase

voltages

U

,.r,

U

6o

and

Upn at

the

st.ar

side

(Fig.

9-8b).

The

reiay

(Fig.

9-?a)

can

be

Lonnetted

by the

ci4cuit

shon'n in Fig.

9-8a

to

ensure

similar

discrimination.

Illustrated

in

Fig.

9-9 is the

circuit

of

a

current

discriminator

for

an

PARC

deviee

instaile.d

at the supply

end

of

the

line. The

current

relays

CRA.

CRB

and

C.RC are

current cut,offs

connected

t.o the currents

of

faulty

phases

v'ith

a

reach covering

the entire transmission

line. If a one-phase

short circuit

occurs.

then one current relay functions

and closes

one of the

auxiliary

rela)ts AnA,

ARB

or

ARC,

u,-hich

trips the faultl'phase

and

triggers

the ARC

device.

The

Iatter

recloses the breakei.

In

the

case

of

unsuccessful

reclosure,

the faulty

phase

is tripped

repeatedly and

the

consumer

is supplied

from

a

two-pha-se and

earth

circuit.

When a

two-

or

three-phase short circuit

occurs!

the circuit

shown

in

Fig.

9-9 assures

the

tripping of all

three

phases

u'ith their

subsequent

automatic

onrrfttrrralortcnl API lpRanJ /Pf frrnnfinn

qlf

v

tv

vr

rraall. aLrru

"With

}ines

supplied

from

both

ends, impedance

relays

with their

phase

-..--^-+ ^*l -^1+^-^ ^^:f ^ ^*^--:-^,1 ^- ,1:-^^{:^-^l i**nJ^-^o -olo-rc ao.rrrinc

outIttllt

auu

YuItdtHY

9utID

vurrrBIZELI

uI LrltEULtt lrol

lrlryquarrw

rerqvYa wra3r

r&6

Fig. 9-9.

Circuit of current

discriminating

elcment

of

PAFC

devjce

for ]jnes

supplied from

one

end

(supply

end)

CRA.

CFB,

CRC

-

contacts of

curent

rela.ys;

e44, A4q,_ARC

-

auxiliar-1'

rela),s;

ARsP

-

auxiriarv

'"'1t;Jrtl t6'Elil*oi:'fi

ooLlF-'"3;f;r"t;"",i.

Bc-c

-

blocking

coh

-

9-10.

Circuit of

PARC

devjce

djscrinrine!ilrn

plernon! pn:nln'i:,rr

Lrrryru-!

rrr6

dance

relay

CPA

CFR

"_

/FSD

.i

.

ARA'I

Ann

LtLar,rl-

-lR*l'

devtce.sterl;ng

Trippinc

of one

or

fhreue

poles

o.a

brealter

310

CEIAPTER

NINE

311

ONE.PEASE

AUTOMATIC

RECLOSTjRE

l1?:.*lfiJrh;r{;1..*

nio

and

tbe

voltage

a*+he

fauity

phase

are

used

as

fautt-v

The

circuit

of

a

discriminator

emproying

an

impedance

relay

is

shou,n

in

Fig'

9-10'

when.earth

i"tlt.-*"rr

the

airrri-io*ior,

.oonected

ro

the

current

and voltage.

of

the

faulty

ph";,

measures

the

imped.ance

lr.,l:Y-!

l/'.

I

!\'hen

oniv

one

phase

i-q

earthed

the

terminal

impedance

of

fhe

fault5'

phase

-

(e_36)

relav

of

the

When

k:

i,,

:

s!rsc,-

i.e.,

the

reiay

terminai

seguence

impedance

fr^m

th,e

relay

ABE

.Ma -I4sc

-o

-21

"y*

(9-39)

impedance

is proportional

to

the

forward_

to

the

point

of

thl

"uorlii"*ii]'fr,"

;;1"r,

Af+o- ^JJi-- ^--r

r

Lr

r's

f

auLIllIH

aflLI

that

for

transmission

-

i!t*"Y".

,

i}".zllse

t

j!yr",!ru

l._:

-

'

-

.

i-lJ

-fl

i#:"

t.

suDtractlng

t

ftsciritrs.

in

the

numerator

and

considering

]ins5

sMsc

J

2gi'",

*-e

obtain

Hence

-.4/..,c

f

Jt{sc

i

jll

s,:

-t

..'

pi.

--

r

o

{r}/".-,11

,.,

_

'ph

?

Mtc

:,,

:

i.ysc

-

*

(z{sc

_

7tu*1

t

;;-

Fig'

9-11'

coanection

diagram

of

PARc

device

discriminating

elernent

empior,-

ioE

diractional

irnpedancerelays

car{rjpg

i,:Upr.

";;;a:;;,,

*

nr,"

(o)

clrcuit

diagram;

(b)

cbaracteristics.sbon,n

as-

coordinatq-3|

l.E

r

-

cbaractertstjc

of

raurted

pirase

rbiiiirl-:iniri.teristic

ar

td;-ii;€;'wbose

Jmpedance

ii

a,

operates,

if

this

impedance

is

l

r,l:l

..9.--'

l=

ru.,

cos

(s

-

.,)

(e.40)

n'here

zp-u

:r*l:ll

pick;up

-ilf6i*t,

r*rte

.diamerer

of

the

characrerisric

circle

as

deierrained-t5r1h.-x'i"a

;x

axes

(Fig

.

g_Lrb)

Li:t"t

if:"Lt:r:he

curren

L

I'p

niki

oand

the

voltage

uo;

impressed

a

:

rela]'

internal

ansle,.determining

the

max-imum

sensitivit5.

region.

The

angie

a is

usilailv

tukl"ls'Equ"r

to

the

angle

of

the

rine

under

protection,

gi

:

60

to

g0

degrJes

lf

the

end

of

l,-e-"tol

+

(b_1,

th-e

axes

r?

and

ia)

'p_,,

js

easily

seen

froin'Fjg.

g_1il

"r;;

;;;r!:1

::::igh-t

""ql:,!:*"d

on

tire

side.zo-,.

conse-

larn

curve

so

that

at,any

values

oI

cos

(rp

_

at

'

:

.,

-"

o"l'r:,,!,

"*"#

r;

lj *t.e"

oi.

r"i

""

i

J c

u t

i

#

arc

near

the insrall";t;;;i-;;:;6-iil.X",r,

r,rre

retay

tn

tbe

case

of

short

ciic.fiir< rhr^,,_I" ^-

rera.v

and

it'-ivp'

"1"

*[,i'iil""'=Tiil:l:1T:!!i',ff,,:;fl"ill'.,ili"l.*i:f?i:H""gliT

3t:'fi:::Xff

tnif

l?,il,per

cent

*;;;i;

"r

r"#iiii"rJl'Jlr,'(tbe

characterisiic

or

rle

rerav

is

(e-37)

(e-38)

-

I*n*l

+

r

*r" 1r,.|1".

-

"trl.",

iMsc

i

en*

kiy*

oMsc

-I

if;;,.1-xi{*

312

CEAPTER NINE

th9*o in

Fig. 9-13

is

a

circuit of

a

pARC-B

device

develo

ed

at,

the

All-Uni-

nstitute

o

The

wide

practical

use

of such

devices in

porver

s1'stems

is mainly

hindered

bl'

the

complexitv

of

the

PARC

device

circuits.

Simnler resuire;ients fnr thp

protection

and

aut.omatic

devices

often

call

for

repia-

cement

of

one-pha-.e

ARC

devices

n'ith three-phase

ones

when

it,

i-s permitted

under

the

operating

condi-

tions

of the

power

-c-ystem.

9-3.

PARC

Circuit

Fig.

9-13.

Circuit diagram

of

PAnC-3

device

DRA,

DRE,

DRC-

contacts

of

dis-

crioinailng

lelars

installed

on

pha-

ses

,{,

B,

C,, AP.A,

IANB,

ARC,

J-4R,

EA.R

-

auxiliary

relay,

type

HIIP-I

i

2ATR,

AATF,

sATR

-

,risy

witb delaTed'

dropout;

'64.R

arLd

zAR

-

auxiliary

reial's;

tTR_

tine

reiaJ;

v.Ro

-

relal

ol zerc.

sequence

voltage;

BC-A,

BC-8,

BC-C

-

blocking

contacts

of break-

ers;

J.R

-

indicatinq

.rela);

S.R

-

sert€s

resrSlor

from

outpul

rclcu

of

protecttan

untti

operoltng

*.,to

tlAC

(lram

Apoa)

6lP-3

7tR-J

5t

t

rclotJ

ttoa

int

?Fqtir?g

rP-

+-.

L

(tu

rno

n{

tdaus

'4*.-t

DPE

@;1y

R]

#v4l

-vL

|

4!y

llrR-t

I-'

ft-}t--l

trR-t

/zt;n i

,E

IAR-

I

tF.F-t

l--4---

ApA-z tRB-3

*/l-/L-

ARE-?/

lPt-J

_

--JL

IRC'2,-

lqh'J

z

t

Y,--Y-!

-i

+

I

;

/7P

LJ

4 7AE

'qtArR

-

*-$;-

3AP-I

'/L

ln

)HJ

IAR.

S

'AR

DC-;

oeYIOe

o

tes

as

f

ts-51

ower

Engineering

for 220-kV

]ines. The

'r-/L

314

CITAPTER

NINE

Tire

relavs 6AR

v

possible

misoperation

of

the

PARC

device

in

the

case of

a

baked contact.

when

a

fault

occurs

on the

other

phases

the

outout

relavs

ocked

and

operation

i9

prohibited

by

contacrs

ARA,

ARB

and

ARC

through

by-

.

On

]ines

sriqf.lie{

at

one

grs,

the

PARC

device

requires

a breaker

ai the

re.

e.piwino on.l \f,i it.h

*h^ oi* ^+ o^-.i*- ^1i:.ipmeni

and

,i-piiiyi"jTir"

secondarv

rn

be

equipped

u'ith

double-shor

TPARC

ontrolled

either

manuaiir.

or

remotell,

the

receiving

end

is

not iurnished

;i;[

ossible

interruptions

to the

po*rer

sup_

atrso

promotes

automatic

reclosures

of

a

PARC

device

is

inst,alled

oa the

line.

rt

circuit

on tire

line,

the

substation

is

le

taken

into

account

when selecting

a

re

substation

i."

furnisired

u'ith

.rmo1._

for.

them.

The

most

practicable

is

the

'e

current

source

automatically

changed

ut,omobile

engine,

for

example)

rvhich

ed.

'nished

with

a

hreaker

at the

receiving

1-|

.p*riiies

thar

pole-after-pole

autol

'ith

:n errf nrnof in ilro-na *^ +--,^ -L^ -^

operation

q'hen

tlie

PARC

operation

is

unsuccessful.

To.speed

rffliru

power

sup-

ply

to

the

load,

when

a

fa,uit

persists

oo

oor

plrse

of

rh6

ri"ulin.

preliminary

work

outlined

below

must

be-

done.

ONE-PIIASE

AU

TOIUATIC

RECLOSURE

(a)

It

is necessar)'

to

ascertain

(with

due

considerati

ansmlsslon

sys

possibili['

of

persisting

-short

circuits

because

of

slect

to

prepare

the

jines

for

two-phase

operation

when

they

;o;l

il;-i.;;;;J

e{(

ting

o{ s}iding

contact

iTR-Z

of

time

rela1,

ITR. The

cJosing

circuit

is

excited

through

the

two

series-connected

contacts

of

relavs

6AR

an{

7AR

to

eliminate

cted

from

the

.4.Rou1

relay.

3r0

CETAPTER NINE

ONE-PEASE

AUTOMATIC

RECLOSURE

317

Itppiy

conditions,

u'hile

other Iines are under

repair.

For this,

the

iine

must

be

tested

(b)

Calculations

and

tests

must

be

carried

out

to

determine

the

maxitrrurn

aiso includes

the

unearthing

of some

transformer

neutral-s in

order to

iimit

tire

zero--qeguence

currents in two-phase

operation

and the installation

of

drainage

coil-s or other devices

ou

the

communication

lines

to

lessen

the

interfr..rr."..

(c)

Instructions

on

the

line

transfer

to tv'o-phase

working

under

emergency

conditions must

be

deveioped

and

issued

to

station

personn-el.

-

(q)

To enable t.he transfer

of

a

given

line

to two-phase

*'orking

without

de-

iav for preparaiion,

for ihis

proi.ective

reia;'i1*

anrj lutomatic

deiices

must

be

used

on

the

line anri

other

elements

of

the

po\r'er

Slrstem.

9-5.

Conclusions

2.

To improve

tbe

operation of ARC

tlevices,

it

is

good

practice

to

combine

the

operation

of PARC and

TPARC device-s.

3.

One-phase

ARC for

single

lines supplied

at one

end needs

the

installation

best

made up

of impedance

reialz5

or

rvith the

aid

of

directional

imped.ance

rela-

I,s

connected to

the

p-hase

voltage

and

current

/pr,

*

Ho.

6.

When a PARC

device

is

installed

on the

iini,

one

must

take

iuto

account

the

fact

that

a

breaker

ya5'trip

tbe

phase-from

one

side

both w-hen

tiis

phase

is

at

an

earth fauit

and

when

it

is

not. Changes

in

the

zero-sequence

current

should

not cause

maifunction

of the

protective

rela,ving,

starting

and d,isorimi-

nating

elements

of

the

PARC

devicei.

9-6.

Review

Questions

l.

Describe tbe

advantages.and

ciisadvantages

of PARC

as

compared

*-ith

HSARC and

asynchronous

ARC

of the

tie

lines.

2.

Substantiate

the

use of

distance-

reiays

for

making

!p -the

discriminating

elements

of PARC

devices,

Wbat

are

the

desirable

characteristi"i-of'tttesl

;;1;;;?'-"

--_,._":_l{,"y .ihl.E,

ciirectionai

power

reiays

connected

ro

,r"o-r"qu"o""'",tr."nt

and

phase

vurtag'es

De lllslalleo

as

dlScrrmrnatrng

elements

ai the

supply

end

of a Iine

sufplied

from

one

end?

4'

\\'hat

are the peculiarities

of

two,phases-earth

operation

of a receiving

substadion?

5.,Tfe.

ope.rafing

current

of

earth-faulr

protection

responsive

to the

3r'^

"oiruot

is chosen

as

needed

for

discri mination

against

an

unbalan"..urt".ili

in

tir"-c"r.

ii''a'n-external

short

:].:_"jl^T^d, igylt:0_3i"; ]\[ust

tlre

operating

setting

of the

prorecrion

le-cningea,

iiit*

iin.

done

and

operators

given

instructions.

/ F l.

device

are-

simply

accomplished

from

the supp}5'

side

through

the

use of

cur-

rent

or

voltage

relays

or by means

of directiohal

power

relays

from

the

recei-

ving

side.

is

s*'i[ched

over to

peiiorm

proiouged

opeiation

r"nder

ttJt;;-ph;.*--;;h

corrdirions?

-,"^

9-^.ltl,Jl

llr,t::_,::l,g.lo_ll.-.:1'-:d.io

zero-seque.n",

"u.r"ot

fo*-it

"

="ppi.r-.ri,;;;;r;

^,r_ Y-

."

1", l"".PruuEULtuu

uu-tllrtsut'eu

L0

_zgl

6-SetUe.n0e

CUffent.

lfom

tfie Supply

SUbStati

side

respond

to

interphase

short

circuits

a[

the

s'ecolC:rr;,,

sice

,:f

tl,*

r,u*,ciiransfornlei

[he receiYing

substation

if the transformer ororrn n^ncrcre ^f .;--lo--i.i-^ *-^--.^-*^--,,,i

rruy

rsrj-'r,uu.

r/u

rilr,sl'puase

suorl

.ulfoul[S

AL

tF.e'gecolrC:lf:!, S;Ct

r:I

Liic

grot,ef

i)_""^nSfotnlei r;I

:l]:,:Y,-t]5:*^:!."Ji_":

il,!,h: transformer

group.coDsisti

of

single-phJse

transtormers ri,ith

thejr

windings

being

star-delta

connected

ufialritre

""ralti"r.'si'"f;;;

ojln" transformer

group

phases

is

disconnected

because

of a

fault?

7. \Vh}'does

the

operation

oI

PARC

devices

influence

the

perlonnance

of overhead

communication

iines?

Give reasons.

^r,^_11^,9o^T,p31. lFe

opera.tio.n

of eiectricai

circuits

with

a

dead-earthed

neutral

and

pole-

a.lter-pole

AHC

devices

on

the Iines

with

the

operation

of circuits

having

their

neutral

eaithed

through

an

arc

extinguishipg.coil.

Is

it^praciieabie

t"

r.- p"1.:;li;;-?;i;'r*"r,r*r".

in

the

cotnpensated

(reactor

earthed)

circuitsl

12' lVhv

is

it

t,hat

most

of

the

faults

on

overhead

transmission

Iine." are

one-phase faults

to

earth?

,^_.,

13. 2_20-Iv

lines

are

furnished

with PARC

devices.

Is it pracricable

ro install TpARC

devrees

on the-se

lines

too?

:lqJP*^RS-gu,:i"..:'

How

can

ibe action

of the

rpnnC

a.ri;e

b;

p."[ilii",i'Jo"iog

operarion

ol the

PARC

device

n'hen

the

former

is

connected

into

the

circriit

.ho","-inligl

A:af

15.

A

dead ending

transmission

line

is

furnished

with

PARC

devices

ine.

b-sl. A

one-

phase

short

cjrcuit

has-occurred

on tbe

phaie

,a

,l

p"int

s7.

n;i;;*"

il;difi!""r,"d berween

tlle I'alugs

Ot the zero-sAfirrpnno.rrrFohtc fl^.,,i--;- +L^ l:*^ r/Ar -.-r r:r:--^ ---L^- ^lr

three phases

of the

break-er

are closed

at,

both

being

disconnected

in the c.esr.sdp rnnnnpr r'+ho

ends

of the line

and

when

the faulty hase

is

It[

and

not

from

tlre

side

of

substation

.,\i).

not

taken

into

account.

tion

to the power

system, the

discriminating

elements of

the

PARC

device are

e

load

curreni-of

the

receiving

substation

js

318

CIIAPTER

NINE

Chapter

I'en

- -

solutioa.

A one-phase

short

circuit

at point

sc.

The

breakerso.f

both

from

ttu

sidc

ol

iubstation

M ani

from'tt,

,ii

"f

iiariiiii""i.

the

zero-sequence

current

in the

poiit

of shori-"ii*ii-l-"t

point

the

three ph.ases

are

cl.oseC

In compliance

s'ith

(g-g)

.SC)

is

rEC

-

r0

-

ipn

x"i'+

Zzf

-7

zzroc

(9-41)

:i:::^,':!'-3"f

3na fef,

are

rhe

fonvard-,

backward-

and

zero-sequence

impedances

reduced

to

the point

o{

short

circuit.

As

the

effect

of

the

receiving

substation

]oad-is

negiected

and

no

generation

is

available

f#fir'J;j:1.0T:t"'

.F,

taken

trr;-;;;;";;r*;h;

;;;i;-F-s;

i,

f;ii:';;i,,,o-,.quon"*

TEREE.PHASE

AUTOMATIC

RECLOSURE

OF

TRANSFORMERS

A}-D

BUSBARS

Eph

10-1.

General

A

cascode

iriooi'ng

o!

a

laulty

ph*f.

Phase'l

ti'tripprd't'rom

thc

sidz of

substation

It[.

From.ylu

sitic

o1

'si.bsiatto"

i,f di

ihr-ior",

pnoses

remain

closed.

(Fip.

g_5).

After

rrippine

a

.phase

fron the

side

dt iulst"i'i*';'-l;;-r.;"_:Lou#t.

current

ar rhe

point

ol

shorf

iircirit

is-aeteimi*a

lv

":pression

(g-gi).

ir

;;;j;;r#i:iirr'fri-34)

rb.e

vaiue

of

_the

cuneot

lightl,r

liowing

from

subdt"tioo

?-

possible

not

only

afrer

clearing

short

after

trip-ping

short

circuits

on tf,e

bu_"_

ver

transformers.

i\{oreover,

the

automa_

different

functions.

Automatic

testing

r8c

The

zero-seguence

cumeDt

-Gsc 1 -Grc '

zfttzf,t'

-Gec

'

-Fec

to

-'l-

-o

flowing

in

the

section

M-SC

is

7'Msc- iGrc-isc

Xt|'

-'o

lF

(w2)

(e-43)

(e44)

i Msc

t0

:

.phase

faiis

to

be

tripped

from

Da eli-up

zero-sequ

eDce

.cuffent

2in

i

Yu:

"f"

+

r?r,

+

A,zf

"i

++1;

To quantitatively

evaluate

tbe

changes

in tbe

current,

assume

that

zfsc

:

4"3..

and

"?'":

"G2"":0.

1

,ft.,

After

the

iaultv

glasg,is

tripped

from,

the

side

of

the

supply

substation,

s,ith

the

above-

mentioned

relationihip-i,

the

cuiient

i; th;';[';g

;i

ii,iti

a"op. abour

25 rimes,

n,hite

r]re

zero-segueDce

current

flo*'ing

in the

line

frdm

the

substation'jiy'

de"ie"*.

alout

10

times.

1l $l|opt

drop

or

rhe

cuneit

at

the

pl;";;i

;hr;-;ir*ir

mai.

;rrtt**

tbe

arc

and

result

in

a successful

pole-after-pole

rr"iosur",-er*

*f.,r,

ihe

phaie

is

t"ifpea

from

one

sjde

oniy.

If

the

faulty

arc

persists,

tbe

the

side

of

substation

.tv- and

the sbort-circuit

vr^u

I

urtL,urLrtrD,

.{-LUrrUIXa

LIg

tg-SLfng

;;;_-.^;;*:;_*j:::_,_o.rl"r,Lue

ousoars-

a-re

deenergized

is most

easy.

Somelprotection

installed

on the

line

from

t

rherer;;;;--'#;";l:i,;ifi1[iirJ""'il"!ii:":f;#;

flT3ffirJ'1,?'T,.

i1'"::to*f]iil".'ii*

#;

opera.ting_conditions,

jr

whicb

a

p.hiie

at

earth

l"uit-ii

iJpptia

;t;;;-;;d.

A

failure

of tbe

back-up

proteciion

ar it,"

*uppty;od;"t

ffus.

th;;fi.il;sion,,of

a

one-

phase

short

circuit.

v

rrr

Lrrri

r.lu-\rJars

ano

rile

power

suppl-r'

to

when

the

busbar-s

s1.g

tripped.

Stiif

*o..

of

the

normal

substatibn

circuit

after

condition.

the

consumers

deenergized

at thi

iime

difficult

is

the

automatic

restoration

finding

that

the

busbars

are

in

Eood

The

most

diffie.rrlf. is fho e,,*^"-^+.

nection

circuit

of the

power

station.

ers

are

Da

tcularly

effeetive

for

cases

of

one-end

}oad,

feeding'from

these

transformers.

As

the

back-up protection

of

the

transformers

is

brought

into

action

when

short

circuits

occur

on

the

L.T.

busbars

(often

no

differential

protection

is used

to

protect

these

buslars)ind

also

when

short

circuits-on

the

outgoing

lines

cannot

be cleared,,

ro6*.rtol

ARC

restores the

power

supply

to the

entire

area.

Instaliation

of

ARC

del-ices

on

the transformers

of

a distribution

network

iying

drilling

derricks).

Infrequenriy

a

;ufficient

to

ensure

its

response to

short

to the

consurrer

is

not isblated

asainst

s motors

driving the

derrick

mechinisms

to

overroad

ariows the

consuncers

ro

r..#rt*tl1*J'r-.""i:t$iT:::T.tJtfii:t$SJr:

signed

starting

secluence.

The

use

of busbar

and

transformer

ARC

is

regarded as

mandatort,

tl0-21.

Rejection

of

their

use

must

be'

substantiated

eacil

ti,ne.

When

busblr and

transformer

ARC

devices

faii

to

operate

or

w'hen thelr

1re

taL:en

out

of ser.,,ice

{tO Undgrso rgnair for instnnep\

qt.nf.inn

noy.ennnal

q}r,',,1'l

i--^"1i.+^1,, -^^l^^^

ih*"o...wq"al"f

'!;;;i;;E;;;;;-";i;;;;i";;;"j;,"t:;';';'(l;;';j;

breaker-s

only')

by hand

on site.

Exceptions are

wiren an

iniolerable

current

surge

occurs

due to

asynchronous

voltaqe.

Ire protections

against

internai troubles

amage

are preseut.

one

reclosure is

per-

rends tlie

tcnsumer's

supplv

[10-2],

eris in

rural

areas

g'ith

their

connection

rrotective

relaf

ing

devices

and

breakers

the problem

of devising

a

device

capab-

es

n'ith good

ones

within

a

specified

Good

results

are

produced

by the

use

of

ARC

devices

on

the

lines

of railrvav

traction

s-vstems.

These

devices

mav

be

widelv

appliedlin

110-220-380-voit

instai-

Iations,

since

daiiy

experience

indicate

that the

c"itses

of a

short

circuit

are

mbst

often self-eliminated

after

deenergizing.

In

a series

of

cases

power

plants

and

substations

use automatic

protection

ciicuit

breakers

to

contrbi

the

cond.i-

tion

of

the

operating

current

circuits

aL

48-220

volts

and

the

potential

trans-

formers

circuits.

It

is

good

practice

to

have

circuit

breakers

of

'a

design

v'hich

assures

ARC

operation.

THREE.PH.ASE

ANC

OF

TRANSFOR}IEFS

AND

EUSBAR.S

10-2.

Automatic

Testing

oiBusbars

for

fnsulation

lli-t^

t,t:"*i

t::trilii:l

"x

:J,:: T,?1,

"-l

:

i'..-,

l::!

y:

o

p

era

r

es

.

a

n

a

c

r i

o

n p

r

o

h

i

b

i

-

t

i

ng

si gna1,

sent

.i*

utt

"ori,rril;

",iii,

?.'i.,i

ll

oni"'i['J'-;;;;]#T""Ti'iil6"iJf

'"":l'ii"1,-":""::1"1J*:.'"^-ll::;";ili-

l1l.r:

connections

except

tor

ihe

::'ff

::';:,lr|.liTsJ':ll,ill:yif

r*:q*{,it.t'*tii""?:i:r'fr

:-*L'i,:*:

lf

,Ti"ff

iii#|""'inll,illl".*"q::::_$;$d';ir;;.";'fr

3'aT.i*:"r',H:

:i,,i*:,,i::::::::*1":l|:;i.;;i$';#;.0*.l:ii,i;l;ll?,fl?rt:;l

;i ;f I";].i; l:"u. _ f :

":

::Iti:

"r

"

-fi,e

ffi

:T

":il:S$:l"j;

;;,11?f

,;:

lfl

:i::

;i'l?,l;Tl#,,JT"*::f

*,,;::,.ji:q.ii";il'i,:"T:i:ti";":?lffi

;Tii,.,lJ;

3j;,:Jy"ding

personnel

either-"i""";rill

l',1"

;'rY"il:l'r"-."

"?...#:?:1ijf*!

CETAPTER

TEN

The

choice

of a

hrpnl,o. inra-r^,1 r^- ..

- -

r

remenr

or

r,eepinJ

irl.

Ji-#;?

{,,"t'r"j;'JTT;TTi

ff:"#flfr[t

#ff::i*"-

fti;

lf#;':ij.Tfr

as

smau

as

pracricabre,

;'i;;ih;

iJrio.u*

is

mide

to

a

per_risring

ot

discriminator-\,.

Hog,ever.

it

ma3,

be

after

recover\-

of

tlie

substatior,

"irtu;i

rotecti

on.

The

principies

underlying

ARC

operations

in

a

series

of

power

S5rs1g*.,

[10-3

and 10-&]

xpd

rormeo

rrom

ru'o

rines.

To

this

end,.";

p;ffi;;tryu

o,iii",

["f:t-#"L:"ffit

de'ices

of the

l"ea[eil$

il'iiler"'tio"Jd"riig"rn.

operation

of

the

differen-

tial

protection.

In

order

to

eaie

the

load

on

the

*st

ces

must

have

air".r"i^pirr.io"r"6inss.

Thi" r,,-o"^?g:-L1tl"]I ll:

Alc

devi-

on the

substation

busbars, used

the

transfor-

Il the

substation

is

sunnliod f.^# **,^*i---,.]__Pil

rs in

the

case

L

a

persisting

short

circuit.

No

asynchronous

rt I r

r!

uatq

De

used.

2t

-2a76

rrDeo rn tne

nex

ARC

o

tions

on

A^ ^ -.1

see

u'O€f,flef

Barzam A.B. Automation in Electrical Power Systems (Системная автоматика)

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