GE L90 Instruction Manual page 276

5.6 CONTROL ELEMENTS
SCHEME 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 is
successful (there is no initiating signal and the breakers are closed) the reset timer will time out, returning the scheme to
the 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, the
scheme 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 open
the 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 the
incomplete sequence timer. The setting of this timer determines the maximum time interval allowed for a single reclose
shot. If a close breaker 1 or 2 signal is not present before this time expires, the scheme goes to "Lockout".
There are four other conditions that can take the scheme to the Lockout state, as shown below:
• Receipt of 'Block' input while in the reclose-in-progress state
• The reclosing program logic: when a 3P Initiate is present and the autoreclose mode is either 1 Pole or 3Pole-A (3 pole
autoreclose for single pole faults only)
• Initiation of the scheme when the count is at the maximum allowed
• 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 be
sent to Lockout. The scheme will be also sent to Lockout if one breaker fails to reclose and the setting
is set to "Lockout".
OPTION
5
Once the Lockout state is set it will be latched until one or more of the following occurs:
• The scheme is intentionally reset from Lockout, employing the Reset setting of the Autorecloser;
• The Breaker(s) is(are) manually closed from panel switch, SCADA or other remote control through the
setting;
CLOSE
• 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 within
30 ms of the Breaker Any Phase Open input. This feature is intended to prevent reclosing if one of the breakers was open
in 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 (
can be transferred direct to the Breaker 2 if
Lockout by the incomplete sequence timer.
2. When the reclosing sequence 2-1 is selected and Breaker 2 is blocked (
can be transferred direct to the Breaker 1 if
Lockout 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:
• Autoreclose scheme is paused after it was initiated.
• Autoreclose scheme is in the Lockout state.
• Autoreclose mode is programmed for three-pole operation
• 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 when
reclosing onto a permanent single phase fault.
• 1.25 cycles after the single-pole reclose is initiated by the
5-186
AR BKR1 BLK
is set to "Yes". If set to "No", the scheme will be sent to
AR TRANSFER 1 TO 2
AR BKR2 BLK
is set to "Yes". If set to "No" the scheme will be sent to
AR TRANSFER 2 TO 1
signal.
AR 1P INIT
L90 Line Differential Relay
5 SETTINGS
AR BKR FAIL
AR BRK MAN
operand is set) the reclose signal
operand is set) the reclose signal
GE Multilin