GE Multilin D60 Line Distance Protection System 5-2675 SETTINGS 5.7 CONTROL ELEMENTS5f) DIRECTIONAL COMPARISON BLOCKINGPATH: SETTINGS CONTROL ELEMENTS PILOT SCHEMES BLOCKING SCHEMEGenerally, the scheme compares the direction to a fault at all terminals of the line. Unlike the permissive schemes, theabsence of a blocking signal permits operation of the scheme. Consequently, the scheme is biased toward dependabilityand requires an "on/off" type of signaling.By default this scheme uses only a forward-looking over-reaching zone 2 distance element to identify forward faults.Ground directional overcurrent functions available in the relay can be used in conjunction with the zone 2 distance elementto increase the coverage for high-resistance faults. Also by default, only a reverse-looking zone 4 distance element to iden-tify reverse faults. Ground directional overcurrent functions available in the relay can be used in conjunction with the zone 4distance element for better time and sensitivity coordination.For proper operation, the zone 2 and 4 phase and ground distance elements must be enabled, configured and set per rulesof distance relaying. If used by this scheme, the selected ground directional overcurrent functions must be enabled, config-ured, and programmed accordingly.In single-pole tripping applications, the scheme uses local fault type identification provided by the phase selector togetherwith information received from the remote terminal.The scheme generates output operands ( DIR BLOCK TX INIT and DIR BLOCK TX1 STOP through DIR BLOCK TX4 STOP) thatcontrol the transmission of signals to the remote end(s). When used with telecommunications facilities the output operandsshould be assigned to operate output contacts connected to key the transmitter at the interface. BLOCKING SCHEMEBLOCKING SCHEMEFUNCTION: DisabledRange: Disabled, EnabledMESSAGE BLOCK SCHEME BLOCK:OffRange: FlexLogic™ operandMESSAGE BLOCK RX CO-ORD PKPDELAY: 0.010 sRange: 0.000 to 65.535 s in steps of 0.001MESSAGE TRANS BLOCK PICKUPDELAY: 0.030 sRange: 0.000 to 65.535 s in steps of 0.001MESSAGE TRANS BLOCK RESETDELAY: 0.090 sRange: 0.000 to 65.535 s in steps of 0.001MESSAGE BLOCK SCHEME SEAL-INDELAY: 0.010 sRange: 0.000 to 65.535 s in steps of 0.001MESSAGE GND DIR O/C FWD:OffRange: FlexLogic™ operandMESSAGE GND DIR O/C REV:OffRange: FlexLogic™ operandMESSAGE BLOCK SCHEME NO OFCOMM BITS: 1Range: 1, 2, or 4MESSAGE BLOCK SCHEME RX1:OffRange: FlexLogic™ operandMESSAGE BLOCK SCHEME RX2:OffRange: FlexLogic™ operandMESSAGE BLOCK SCHEME RX3:OffRange: FlexLogic™ operandMESSAGE BLOCK SCHEME RX4:OffRange: FlexLogic™ operandMESSAGE BLOCK SCHEME EVENT:OffRange: FlexLogic™ operand
