GE Multilin L90 Line Differential Relay 5-1375 SETTINGS 5.5 GROUPED ELEMENTS5ï BF1 N AMP LOSET PICKUP: This setting sets the neutral current output supervision level. Generally this settingshould 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.ï BF1 LOSET TIME DELAY: Sets the pickup delay for current detection after opening resistor insertion.ï BF1 TRIP DROPOUT DELAY: This setting is used to set the period of time for which the trip output is sealed-in. Thistimer 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 Tripsignal on longer than the "reclaim" time.ï BF1 PH A INITIATE / BF1 PH B INITIATE / BF 1 PH C INITIATE: These settings select the FlexLogicô 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.ï BF1 BKR POS1 φB / BF1 BKR POS 1 φC: These settings select the FlexLogicô operand to represents the protectedbreaker 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 for1-pole breaker failure schemes.ï BF1 BKR POS2 φB: Selects the FlexLogicô operand that represents the protected breaker normal-type auxiliaryswitch contact on pole B (52/a). This may be a multiplied contact. This setting is valid only for 1-pole breaker failureschemes.ï BF1 BKR POS2 φC: This setting selects the FlexLogicô operand that represents the protected breaker normal-typeauxiliary switch contact on pole C (52/a). This may be a multiplied contact. For single-pole operation, the scheme hasthe same overall general concept except that it provides re-tripping of each single pole of the protected breaker. Theapproach shown in the following single pole tripping diagram uses the initiating information to determine which pole issupposed to trip. The logic is segregated on a per-pole basis. The overcurrent detectors have ganged settings. Thissetting 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 givenvia output operand BKR FAIL 1 TRIP OP.
