Power Research & Development Consultants Pvt. Ltd.#1Protection Two typesunit non unitlinenon unit type (distance)Comparenit typePrimary & !ac" # upprotectionslocalremote$one o% protection Power Research & Development Consultants Pvt. Ltd.#&Distance relays(non' unit)relay(a1) (a2 ) (a0%ault$1) $2 ) $0 Power Research & Development Consultants Pvt. Ltd.#*Distance Relay+,pressions %or (mpedance calculations(Positive se-uence impedance)Phase to .round /ault(a'0)1A2 (a1 $1 3 (a2 $2 3 (a0 $0 2 (a1 $1 3 (a2 $2 3 (a0 $0' (a0 $13 (a0 $12$14(a1 3 (a2 3 (a0 5 3 $1$0 ' $1$1(a02$14 (a 3 *"(a0 567 $ero se-uence compensation %actor 62$0 ' $13 $1 Power Research & Development Consultants Pvt. Ltd.#8Phase to Phase %ault(9'c)(b 2 ' (c : (b0 2 ' ; : (c0 2 ' ; :1b2 (b1 $1 3 (b2 $2 2 (b $1 1c2 (c1 $1 3 (c2 $2 2 (c $1 21b #1c (b #(c$14(b #(c 54(b #(c 52$1 Power Research & Development Consultants Pvt. Ltd.#3=>?o LoadLoadReverse Power Research & Development Consultants Pvt. Ltd.#@Poly'phase protection* ph'ph* ph'.relays1 &*T3T3$3$2T2T1$1$4Reverse%ault/orwardRelayT2$2T1$1 Power Research & Development Consultants Pvt. Ltd.#A$1$2$3$4RB,B,$3$2$1$4R' Transients in volta0e & current inputs' Load +ncroachment' Tolerance %or %ault resistance(RF)' Power swin0 e%%ects' Parallel lines: Cutual couplin0 Power Research & Development Consultants Pvt. Ltd.#DEwitched Distance protection Ewitchin0 networ"s to ensure measurin0 elements connected to correct phase under %ault conditions Ewitchin0 networ"s controlled 9y %ault detectors responsive to current) impedance or com9ination o% current and volta0e.Limitations7 Fperatin0 time increases /irst to identi%y the %ault phases To switch the measurin0 elements to correct phases Power Research & Development Consultants Pvt. Ltd.#G+,7 $one'1 Fperation re-uires * %unctions startin0Phase selectionmeasurementPoly phase distance protection Does not use special switchin0 or phase selective networ"s 9ut use special com9ination o% relayin0 si0nals Power Research & Development Consultants Pvt. Ltd.#1;Etartin0 relaysFperates %or selected phases dependin0 on type o% %ault and ener0ies switchin0 networ"s %or measurin0 elementsFvercurrent starter relaysCurrent settin0 considerations7Depends on ma, load current) ma,. sound phase currentsTo provide 9ac"'up %unctionnder volta0e starter relaysResistance earthed systems(* phase # to # neutral connected under volta0e element)(mpedance starter relay(mproves %ault covera0e Power Research & Development Consultants Pvt. Ltd.#11Distance protection 9ased on in%ormation lin"sTo avoid delayed operation %or internal %aults 9eyond Hone'1 settin0 Provides co'ordinated trippin0 9etween line ends(n%ormation lin" throu0h pilot'wire) power # line # carrier.Trippin0 Echemes Received si0nal is used %or direct trippin0 Received si0nal and the conditions o% the relays at the receivin0 endThree 9asic arran0ements 9ased on trip command Direct inter trippin0 permissive under reach permissive over reach Power Research & Development Consultants Pvt. Ltd.#1&Direct trippin0 operation o% relays at either end initiate trippin0 at that end and transmits the in%ormation to initiate trippin0 9y remote end relays should ensure correct trippin0 in the presence o% inter%erencePro9a9ility o% incorrect trippin0 as speed o% communication channel increases Ipplied mainly to trans%ormer %eeder where circuit 9rea"er is not associated with trans%ormerPermissive inter trippin0 Trippin0 action o% received si0nal is made dependant on %ault detectin0 relayReduces the ris" o% unwanted trippin0 due to noiseJinter%erence Power Research & Development Consultants Pvt. Ltd.#1*Permissive under reachi. Kith independent controlL Fperates independently o% the received inter trip si0nalL (nstantaneous operation o% $one'& and operation o% receive relay results in trippin0ii. Iccelerated distance protectionPermissive inter trip # over reachin0L $one'1 relays with e,tended reach L Trippin0 at each end depends on the operation o% Hone'1 relay at 9oth ends Power Research & Development Consultants Pvt. Ltd.#18Disadvanta0e/or low %ault level) trippin0 at one end is delayed) resultin0 in delayed operation!loc"in0 Echemes 9loc"s the operation on detectin0 reverse %aults at a relay location either end 9loc"s the operation o% other Power Research & Development Consultants Pvt. Ltd.#1FRF>BR'a,isRIDR(LIT+RIL CSIR F/ TRICT(F? R+ILQ Power Research & Development Consultants Pvt. Ltd.#&8Rcal21cos T(cos31sin T (sin(cos T(cos3(sin T (sin>cal21sin T(cos'1cos T (sin(cos T(cos3(sin T (sinLo0ic7a) D(ETI?C+ PRFT+CT(F?>B

cal

fRB 3>caltanM Rcal< Rf >caltan3 Power Research & Development Consultants Pvt. Ltd.#&F1)Tcot FR(% >B2M >cal M >B1: RB1 3 (>cal ' >B1)Tcot M Rcal M RF1 ' (>cal ' >B1)Tcot (% >F2M >cal M >F FR>B M >cal M >B2 : RB M Rcal M RFFR Power Research & Development Consultants Pvt. Ltd.#*;Khere RF) RF1 and RB ) RB1 are resistance reach settin0 in the %orward and reverse direction respectively. >F) >F1 and >F2 are%orward reactance reach settin0s. >B) >B1 and >B2 arereverse reactance reach settin0s. is the settin0 an0le.Rcal and >cal are computed values o% R and > Power Research & Development Consultants Pvt. Ltd.#*1Power Ewin0sL Eur0es o% Power resultin0 a%ter the removal o% a short circuit.LResultin0 %rom connectin0 a 0enerator to the system at an instant when they are out o% phase(Loss o% Eynchronism).Power Ewin0 !loc"in0L Ceasured impedance should lie in power swin0 9and %or more than the preset value o% the timer (in ms)L Relay operation 9loc"ed %or %ew seconds Power Research & Development Consultants Pvt. Ltd.#*&>Ro%%set$one'*$one'&$one'1(R3>3)(R2>2)(R1>1) Power Research & Development Consultants Pvt. Ltd.#**R1 2$1$cos >1 2$1$sin R2 2$2$cos >2 2$2$sin R3 2$3$cos '$offse&cos >3 2$3$sin '$offse&sin $one'1$one'&$one'* Power Research & Development Consultants Pvt. Ltd.#*8Relay Eettin0s$1) $2) $1)$one'1) $one'& & $one'* %orward reach settin0s$offseReverse reach settin0 %or $one'*Characteristic an0le to suit line an0le(8cal 7 Ceasured values o% Resistance & Reactance computed usin0relayin0 al0orithm))R) > 7 Relay reach settin0s) (R1 ' >1)%or $one'1) (R2 # >2)%or $one'&) (R3 # >3)%or $one'*r 7 computed value o% radius Power Research & Development Consultants Pvt. Ltd.#*@/ault Detection Lo0icr& M r&! r&! 7 Etored threshold values o% s-uare o% radius . Compared %or threeDi%%erent Hones (Hone detection)Timers o% predetermined relays are initiated i% the %ault is detected in $one'&and $one'* Power Research & Development Consultants Pvt. Ltd.#*ALoadLoadIdditional%aultcovera0e>>F>F2>F1>B2>B1RB1RF1RFRB>BR/ault characteristic o% Distance Relay Power Research & Development Consultants Pvt. Ltd.#*DConclusions di0ital distance relayin0 schemes 9ased on DEP processors have led to the reassessment o% relayin0 al0orithms %or developin0 hi0h per%ormance numeric distance relays.Euita9le pre'%ilterin0 techni-ues 9ased on ((R and /(R %ilters improves the per%ormance o% numeric relays.+valuation studies show that short data window al0orithms can 9e used %or hi0h speed distance desi0nsCultiprocessor 9ased con%i0uration %or hi0h speed and accurate distance relay desi0ns has 9een proposed.The relia9ility o% multiprocessor 9ased relays can 9e improved 9y e,ecutin0 several al0orithms in parallel and 9y FRJI?D 0atin0 their outputs to issue trip si0nal durin0 %aults.