GE L90 Instruction Manual

Also see for L90: Communications manual Communications guide Instruction manual Instruction manual Instruction manual

Contents

5-186 L90 Line Differential Relay GE Multilin5.6 CONTROL ELEMENTS 5 SETTINGS5SCHEME RESET AFTER RECLOSURE:When a reclose output signal is sent to close either breaker 1 or 2 the reset timer is started. If the reclosure sequence issuccessful (there is no initiating signal and the breakers are closed) the reset timer will time out, returning the scheme tothe reset state, with the shot counter set to 0, making it ready for a new reclose cycle.In two breaker schemes, if one breaker is in the out-of-service state and the other is closed at the end of the reset time, thescheme will also reset. If at the end of the reset time at least one breaker, which is not in the out-of-service state, is openthe scheme will be sent to Lockout.The reset timer is stopped if the reclosure sequence is not successful: an initiating signal present or the scheme is in Lock-out state. The reset timer is also stopped if the breaker is manually closed or the scheme is otherwise reset from lockout.LOCKOUT:When a reclose sequence is started by an initiate signal the scheme moves into the reclose-in-progress state and starts theincomplete sequence timer. The setting of this timer determines the maximum time interval allowed for a single recloseshot. If a close breaker 1 or 2 signal is not present before this time expires, the scheme goes to ìLockoutî.There are four other conditions that can take the scheme to the Lockout state, as shown below:ï Receipt of ëBlockí input while in the reclose-in-progress stateï The reclosing program logic: when a 3P Initiate is present and the autoreclose mode is either 1 Pole or 3Pole-A (3 poleautoreclose for single pole faults only)ï Initiation of the scheme when the count is at the maximum allowedï If at the end of the reset time at least one breaker, which is not in the out-of-service state, is open the scheme will besent to Lockout. The scheme will be also sent to Lockout if one breaker fails to reclose and the setting AR BKR FAILOPTION is set to ìLockoutî.Once the Lockout state is set it will be latched until one or more of the following occurs:ï The scheme is intentionally reset from Lockout, employing the Reset setting of the Autorecloser;ï The Breaker(s) is(are) manually closed from panel switch, SCADA or other remote control through the AR BRK MANCLOSE setting;ï 10 seconds after breaker control detects that breaker(s) were closed.BREAKER OPEN BEFORE FAULT:A logic circuit is provided that inhibits the Close Breaker 1(2) output if a reclose initiate (RIP) indicator is not present within30 ms of the Breaker Any Phase Open input. This feature is intended to prevent reclosing if one of the breakers was openin advance of a reclose initiate input to the recloser. This logic circuit resets when the breaker is closed.TRANSFER RECLOSE WHEN BREAKER IS BLOCKED:1. When the reclosing sequence 1-2 is selected and Breaker 1 is blocked ( AR BKR1 BLK operand is set) the reclose signalcan be transferred direct to the Breaker 2 if AR TRANSFER 1 TO 2 is set to ìYesî. If set to ìNoî, the scheme will be sent toLockout by the incomplete sequence timer.2. When the reclosing sequence 2-1 is selected and Breaker 2 is blocked ( AR BKR2 BLK operand is set) the reclose signalcan be transferred direct to the Breaker 1 if AR TRANSFER 2 TO 1 is set to ìYesî. If set to ìNoî the scheme will be sent toLockout by the incomplete sequence timer.FORCE 3-POLE TRIPPING:The reclosing scheme contains logic that is used to signal trip logic that three-pole tripping is required for certain conditions.This signal is activated by any of the following:ï Autoreclose scheme is paused after it was initiated.ï Autoreclose scheme is in the Lockout state.ï Autoreclose mode is programmed for three-pole operationï The shot counter is not at 0, i.e. the scheme is not in the reset state. This ensures a second trip will be three-pole whenreclosing onto a permanent single phase fault.ï 1.25 cycles after the single-pole reclose is initiated by the AR 1P INIT signal.