GE L90 Instruction Manual page 227

5 SETTINGS
• BF1 N AMP LOSET PICKUP: This setting sets the neutral current output supervision level. Generally this setting
should detect the lowest expected fault current on the protected breaker, after a breaker opening resistor is inserted
(approximately 90% of the resistor current). This setting is valid only for 3-pole breaker failure schemes.
• BF1 LOSET TIME DELAY: Sets the pickup delay for current detection after opening resistor insertion.
• BF1 TRIP DROPOUT DELAY: This setting is used to set the period of time for which the trip output is sealed-in. This
timer must be coordinated with the automatic reclosing scheme of the failed breaker, to which the breaker failure ele-
ment sends a cancel reclosure signal. Reclosure of a remote breaker can also be prevented by holding a Transfer Trip
signal on longer than the "reclaim" time.
• BF1 PH A INITIATE / BF1 PH B INITIATE / BF 1 PH C INITIATE: These settings select the FlexLogic™ operand to ini-
tiate phase A, B, or C single-pole tripping of the breaker and the phase A, B, or C portion of the scheme, accordingly.
This setting is only valid for 1-pole breaker failure schemes.
φ
• BF1 BKR POS1 B / BF1 BKR POS 1
breaker early-type auxiliary switch contact on poles B or C, accordingly. This contact is normally a non-multiplied Form-
A contact. The contact may even be adjusted to have the shortest possible operating time. This setting is valid only for
1-pole breaker failure schemes.
φ
• BF1 BKR POS2 B: Selects the FlexLogic™ operand that represents the protected breaker normal-type auxiliary
switch contact on pole B (52/a). This may be a multiplied contact. This setting is valid only for 1-pole breaker failure
schemes.
φ
• BF1 BKR POS2 C: This setting selects the FlexLogic™ operand that represents the protected breaker normal-type
auxiliary switch contact on pole C (52/a). This may be a multiplied contact. For single-pole operation, the scheme has
the same overall general concept except that it provides re-tripping of each single pole of the protected breaker. The
approach shown in the following single pole tripping diagram uses the initiating information to determine which pole is
supposed to trip. The logic is segregated on a per-pole basis. The overcurrent detectors have ganged settings. This
setting is valid only for 1-pole breaker failure schemes.
Upon operation of the breaker failure element for a single pole trip command, a 3-pole trip command should be given
via output operand
BKR FAIL 1 TRIP OP
GE Multilin
φ
C: These settings select the FlexLogic™ operand to represents the protected
.
L90 Line Differential Relay
5.5 GROUPED ELEMENTS
5-137
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