INSTRUCTIONS INTRODUCTION

Transcription

1 Westinghouse. L NSTALLATON OPERATON MANTENANCE NSTRUCTONS TYPES HKB/TCU - SKB/TCU & SKBU RELAYS NTRODUCTON This instruction leaflet describes the overall functioning of HKB/TCU, SKB/TCU and SKBU relays when used in conjunction with a TC power line carrier channel. Detailed description of operation, as well as setting and maintenance recommendations for the individual relays for the phase comparison system are covered in the individual relay instruction leaflets; intended to supplement these relay instructions. Unless other1vise stated, the HKB/TCU, the description here is the following sections of this leaflet apply to all SKB/TCU and SKBU relaying systems. APPLCATON Phase comparison carrier relaying is a well established system for the high speed protection of power transmission lines. The type HKB, SKB and SKBU relay are the high speed carrier relays used in conjunction with power line carrier equipment to provide complete phase and ground fault protection of a transmission line section. The basic concept of these schemes are the same as differential relaying. These relays operate on line current only, and no source of ac line potential is required. Consequently, it will not trip during a system swing or out-of-step conditions. For normal application for two-terminal lines, the fault detector settings are determined from a comparison of the maximum load and minimum fault currents. With the required 1.25 ratio between FD-2 and FD-1 pickup, can usually be obtained. reasonaole settings For three-terminal lines which approximately have equal currents fed in two-terminals and the current sum flows out the third terminal of the line, used. the ratio of 2.5 oetween FD-2 and FD-1 pickup should be Since these relaying systems operate only during a fault, the carrier channels are available at all other times for the transmission of other functions. EQUPMENT COMPLEMENT The equipment complement of these relaying systems are listed in Table. The functions of each unit are: NEW NFORMATON EFFECTVE MARCH 1968

2 interuptions in carrier caused by arcing over of protective gaps in the tuning equipment. The unction of the squelch circuit is to hold off the carrier for a period of 150 ms after the breaker "a" contact opens. This is to prevent undesirable carrier blocking of another terminal which might be somewhat slower in tripping because of a lower value of fault current or of some other reasons at that terminal. External Fault During an external fault, when the fault detectors pickup. Carrier is transmitted from the two ends of the line on alternate half cycles. This occurs because the current at one end of the line has reversed with respect to the current for an internal fault. n this case, the local (or remote 0 if current reversed at the remote end) squaring amplifier will be shifted 180, in Fig. 5, as shown i.e. the input from the remote squaring amplifier of the comparer AND will have a blocking signal while the local squaring amplifier output has a tripping signal. As a result there will be no tripping signal output from the comparer and tripping will be blocked. Transient Blocking Since the sequence filter and the low pass filter contain reactive circuit elements, discharge of their stored energy after the clearing of an external fault might cause an incorrect relay operation or a false tripping may result during a sudden reversal in the direction of fault power flow in the protected line, due to the sequential clearing of a fault on a parallel line. n order to improve the security of this relaying system against such conditions, transient blocking circuit has been added. For any fault, operates, if tripping does not occur in less than 2 cycles after FD-2 the Flip-Flop will be desensitized so that a transient pulse cannot operate it. However, if an internal fault developes before the external fault is cleared, the change in phase position of the local and remote carrier pulses will cancel the transient blocking after approximately 2 cycles to allow a slightly delayed tripping. SYSTEM FUNCTONAL TEST PROVSONS t is desirable to check periodically the condition of the carrier set to determine its ability to send and receive a carrier signal. a test switch 85/PB is connected to the carrier start elements. a For this purpose Pressing the test pushbutton sends a carrier signal which is received by the remote receiver to operate an alarm relay TT-l and energize a milliammeter. set is not functioning properly, does not deflect, f the carrier the alarm is not heard and the milliammeter indicating trouble which must be investigated and corrected. Operation of these relaying systems for all faults are dependent upon correct functioning of the carrier equipment components as l rell as the HK8, SKB or SKBU relay itself. The test facilities which including a type W2 switch and a special testing transformer provide a simple manually operated test procedure for these systems that will check the combined relay and carrier equipment. Detailed test procedure is described in.lr and , for the HKB/TCU, SKB(TCU, and SKBU phase comparison relaying systems respectively. -4-

3 " T T TERMNALS.(408C367) lr OF TC OR TCU SET. 8U/TC Phase Comparison Relaying System. TRP CRCUT -6- " 18,., 8-P! 85-RS 85-TR 8 -TS POSTON CON PUL PUSH T2 T1 OFF '. L AB AB 12 CARR 11: RELAYNG AB AB 5 AB 6... AB 7 TfST t """'\ ron CD,..,. CD 12 CD 0 CD 5 ) CD 6 to 1 EF EF EF EF 5 EF 6 NTE::NAL EF 7 TT-l RELAY SCHEMATC i88a123 TYPE Ht(8 RELAY 88A291 Ji:\1n:ST ltuhuttom -- RESERVE SiGNAL TEST!29C703 TEST RDf[T 'USH8UTTetf - CARRER TEST SWTCH(W21 -- rt[st SWTCH S UPf>LEO WTH] ASSU18LED COMlCTCMS THUS ETERNAL CONNTONS NEED ONLY H: MADE AT DESGNATED - TERMNAL E' 85 TS ""F- WESTNGHOUSE MAD N U.S.A

4 TRPPNG Olii[CTON... U' o- LNE TRAP " ',. " 0, '1 ',,..... " " c 2,. 5 CARRER TEST SWTCH 1/TS afbu df1 T2 Tl f5[5 F6 6 2,..., i 2 SKBU SEQ NETVQK i: TEST TRANSFORMER fl V 60 CYC ( 1..,JfASE WTH REMOTE END) H LOW-PAS FLTER PHAS!: " SPLTT!:" TUNER :t! FD-2 ' -- ''o--l!:::;.. --n.. CARR Ti T...:,-: T,' Lf TS... fi!""' COUAL CABLE TO CAUtl[lt CANET lll " l ri....,. r 3 reyng Jl CRCUT t!--j '' g!; ' i U snunch +45V S,:;; WTR i kl.-:r. "'' l F )"'3" -!----- NORMAL L----+-,-- ONDUCTED jl>t!l;> c!>--.., Rl...,.PN CONNECTOR OF SKBU Fig. 2 External Connection of SKBU/T j

5 120V 60"-' TEST SOURCE {N PHASE WTH RUlOTE ENOl Fig. 1 COA TO TYPETC CARRER SET TRANSFORMER {SEC) SHELDED TW STED PAR (SHELD GROUNDED} l o CARRER CABN!.,.PN CONNECT External Connection of HKB/T

6 c-} CARRER LL RECEVED ALARM C Phase Comparison Relaying System. BkR NO 2 TRP CRCUT POS-G- -8- DE\/ NO DEVCE 74 TT-l RE LAY 1848 AA41 78 SKBU RELAY 17& : B51 rs TYPE W2 TEST SWTCH TC TR-1 RE AY TC CARRER SET 3R A 99. L B<R' NO TRP CRCOlT POS " ' T '" ,..... Tit CARR[R 0" TEST TEST 2 0 ON ( ON 'vi[w 9 H ' CS " Yi... as,rs TYPE W> CARR RlillSWJCJ, POSTON TE T CONTA f ()1j HANoLE OUT HANO.[ OUT.. N,. A5-8" A6-B6 A7-8, Cl Dl - K - G -H G7-7 : DENOTES CONTACT CLOSED 5476Dl7 --

7 A L Fig. 4 NTERNAL FAULT A B (\[\[V f---i 1---f J---1 -alock J l-..j 1--J -- -TRP '-- local and remote squaring ampllfien have tripping output during them lnle,...lt when ca"le< 1101 tra...,..ltted. 87 HKB, SKB,S<BU 17 TCU + 87 AND 87 ARE N A SAME PACKAGE FOR S<BU. 87 AA D1.] TRP N N ELAY d 1 t;( : g: L 1 j HKB/TCU/TC SYSTEM ONLY j 863A193 Block Diagram of Phase Comparison Relaying Logic. -LOCK -TliiP Fig. 5 LOCAL SEQUENCE NETWORK OUTPUT LOCAL SQUARNG AMPliFER OU11'J1' local CARRER REMOTE CARRER REMOTE SQUARNG AMPLFER 01J11'111' TRPPNG PULSES Phase Comparison Transmitter Keying ETERNAL FAULT A B NONE NoM that remote squaring amplifier oul has contlnuaus blocling polarity o external fault, since t responds to i the local and,.,..,.. co"*' sig'

8 ST 0 PAR toundfd) l8c423) T CR7 T U: PHONE JACkS ON $W TCHOAftO,(FRONT VEW! Jl AT RGHT J2AT LEFT) Phase Comparison Relaying System. TRP CRCUT POS,tr- res± CS CS.Ut 78 TO -10- BACK UP RELAY DEVCE NO. 74,.,., 15-P 85-RS &-Tit 85-TS. L TS W2 CARR. TEST SW ONT AB POSTON ol pnsh Tl Tl f""i"" ON... AB'l AB NAMEPLATE AB 5 AB 6 AB7 o.. CD n:st \ ro CD2 TE:ST2-=-0 :::- CD co 5 CD 6.J \ 0 7 EF ff12 EF EF EF 6 EF 7 HHUNAL CH:rolTC W STNGHOUR MAD( 1ft U.S A. TVPl TT-l RELAY lha 323 fyh SQ MlAY TCU S(T CAtlti.R TU'T ltus...,tton RESU' ltcttal TUT lltc701 TilT ltt: T 'USHeUTTON CARRDt T!:ST SWTCH (W2) J ltest SWTCH S SUPPU 0 WTiol ASSfML[D CONN!TOS THUS ETERNAl CONNECTfOM 1ED ONLY E W.OE AT DSGNAT!O Tf ltiiin.a.. fl : U:.ll Fl 5476Dl6

9 TRPPNG DRECTON TEST TRANifOtM[t "-' TEST SOURCE (N PHASE WTH REMOTE END) -9- Fig. 3 COA TO TYPE TC CARRER SET r CARRER SKB SAT TRA 1- SEC WNDN CAE ---.>-PN CONNECTO External Connections of SKB

10 . L lfestnghouse ELECTRC CORPORATON ELAY-NSTRUMENT DVSON NEWARK, N. J. Printed in U.S.A.