Tele-Protection Signal List for 132 kV Line Protection:132 kV
Line Protection with Distance (21) Relay as Main & Directional
Over
Current/Earth Fault (67/67N) as Back-upRelay Type Signal
Remarks
Main (21) 21 Tx (Distance Sent) Generally Under-Reaching21 Rx
(Distance Received)
Back-up (67N)67N Tx (DSEF/DEF Sent)
Generally Over-Reaching67N Rx (DSEF/DEFReceived)
Breaker Fail
DTT-1 (Direct TransferTrip) Rx Separate Communication Channels
should be
Used for Each Signal SentDTT-2 (Direct TransferTrip) Rx
DTT-1 (Direct TransferTrip) Tx Separate Communication Channels
should be
Used for Each Signal ReceivedDTT-2 (Direct TransferTrip) Tx
132 kV Line Protection with Line Differential (87L) Relay as
Main & Directional OverCurrent/Earth Fault (67/67N) as
Back-up
Main (87L)Inter-Tripping Signal should be Internally Sent/r
by the Same Fibre-Optic Channel with Whichboth End 87L Relays
are Communicating.
Back-up (67N)67N Tx (DSEF/DEF Sent)
Generally Over-Reaching67N Rx (DSEF/DEFReceived)
Breaker Fail
DTT-1 (Direct TransferTrip) Rx Separate Communication Channels
should be
Used for Each Signal SentDTT-2 (Direct TransferTrip) Rx
DTT-1 (Direct TransferTrip) Tx Separate Communication Channels
should be
Used for Each Signal ReceivedDTT-2 (Direct TransferTrip) Tx
