GE L90 Instruction Manual page 569

CHAPTER 5: SETTINGS
• 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 three-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; that is, the scheme is not in the reset state. This ensures a second trip is three-pole when
reclosing onto a permanent single phase fault.
• 1.25 cycles after the single-pole reclose is initiated by the
Zone 1 extent
The zone 1 extension philosophy here is to apply an overreaching zone permanently as long as the relay is ready to
reclose, and reduce the reach when reclosing. Another zone 1 extension approach is to operate normally from an
underreaching zone, and use an overreaching distance zone when reclosing the line with the other line end open. This
philosophy can be programmed via the line pickup scheme.
The "Extended Zone 1" is 0 when autoreclose is in lockout or disabled and 1 when autoreclose is in reset.
• When "Extended Zone 1" is 0, the distance functions are set to normal underreach Zone 1 setting
• When "Extended Zone 1" is 1, the distance functions can be set to Extended Zone 1 Reach, which is an overreaching
setting
• During a reclose cycle, "Extended Zone 1" goes to 0 as soon as the first CLOSE BREAKER signal is issued
0) and remains 0 until the recloser goes back to reset
>
Settings
The single-phase autoreclose settings are as follows.
— This setting selects the Autoreclose operating mode from the four available reclose modes (Mode 1: 1 & 3 Pole,
AR MODE
Mode 2: 1 Pole, Mode 3: 3 Pole-A and Mode 4: 3 Pole-B), which functions in conjunction with signals received at the initiation
inputs as described. The autorecloser runs in this mode until a different mode is activated through the AR Mode Activation
inputs explained as follows.
to — This setting selects an operand for activating the corresponding AR mode in runtime. Mode
Mode 1 Mode 4 Activation
change via activation input takes place when only one of the four activation inputs is high and the
(that is, reclose is not in progress) and also the mode to be activated is different from the existing mode, otherwise the
activation input is ignored and the existing mode continues to be used. See details in the Mode Control Logic diagram.
— This setting specifies the number of reclosures that can be attempted before reclosure goes to
AR MAX NUMBER OF SHOTS
lockout when the fault is permanent.
— This setting selects the autoreclose initiation mode. When selected as "Protection AND CB," the
AR INITIATE MODE
autoreclose element is initiated by protection operation and begins incrementing the autoreclose dead time timer when a
circuit breaker is open. Breaker status is determined from breaker auxiliary contacts which need to be correctly configured
in breaker settings. In "Protection only" initiation mode, the autoreclose element is initiated by protection operation and
begins incrementing the dead time when protection resets, without the need of breaker auxiliary contacts.
— This input selects an operand that blocks the reclose command for breaker 1. This condition can be for
AR BLOCK BKR1
example: breaker low air pressure, reclose in progress on another line (for the central breaker in a breaker and a half
arrangement), or a sum of conditions combined in FlexLogic.
— This setting represents the closing time for the breaker 1 from the moment the "Close" command is
AR CLOSE TIME BKR1
sent to the moment the breaker contacts are closed in the "Protection AND CB" mode or when Open Pole is reset in the
"Protection only" mode. In the "Protection Only" mode,
case of the unsuccessful reclose attempt or 20 ms after Open Pole is reset in case of the successful reclosure attempt.
L90 LINE CURRENT DIFFERENTIAL SYSTEM – INSTRUCTION MANUAL
(AR BKR2 BLK
is set to "Yes." If set to "No" the scheme is sent to
AR TRANSFER 2 TO 1
signal
AR 1P INIT
is reset if either protection operates again in the
AR1 CLOSE BRK 1
CONTROL ELEMENTS
operand is set) the reclose signal
(AR SHOT COUNT
operand is low
AR RIP
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