GE b30, Instruction Manual, Page: 424 / 632

5-216 B30 BUS DIFFERENTIAL SYSTEM – INSTRUCTION MANUAL
GROUPED ELEMENTS CHAPTER 5: SETTINGS
5
BF1 N AMP SUPV PICKUP
— This setting is used to set the neutral current initiate and seal-in supervision level. Generally this
setting detects the lowest expected fault current on the protected breaker. Neutral current supervision is used only in the
three phase scheme to provide increased sensitivity. This setting is valid only for three-pole tripping schemes.
BF1 USE TIMER 1
— If set to "Yes," the early path is operational.
BF1 TIMER 1 PICKUP DELAY
— Timer 1 is set to the shortest time required for breaker auxiliary contact Status-1 to open, from
the time the initial trip signal is applied to the breaker trip circuit, plus a safety margin.
BF1 USE TIMER 2
— If set to "Yes," the main path is operational.
BF1 TIMER 2 PICKUP DELAY
— Timer 2 is set to the expected opening time of the breaker, plus a safety margin. This safety
margin was historically intended to allow for measuring and timing errors in the breaker failure scheme equipment. In
microprocessor relays this time is not significant. In B30 relays, which use a Fourier transform, the calculated current
magnitude ramps-down to zero one power frequency cycle after the current is interrupted, and this lag needs to be
included in the overall margin duration, as it occurs after current interruption. The Breaker Failure Main Path Sequence
figure that follows shows a margin of two cycles; this interval is considered the minimum appropriate for most
applications.
Note that in bulk oil circuit breakers, the interrupting time for currents less than 25% of the interrupting rating can be
significantly longer than the normal interrupting time.
BF1 USE TIMER 3
— If set to "Yes," the Slow Path is operational.
BF1 TIMER 3 PICKUP DELAY
— Timer 3 is set to the same interval as timer 2, plus an increased safety margin. Because this
path is intended to operate only for low level faults, the delay can be in the order of 300 to 500 ms.
BF1 BKR POS1
φ
A/3P
— This setting selects the FlexLogic operand that represents the protected breaker early-type auxiliary
switch contact (52/a). When using the single-pole breaker failure scheme, this operand represents the protected breaker
early-type auxiliary switch contact on pole A. This is normally a non-multiplied form-A contact. The contact can even be
adjusted to have the shortest possible operating time.
BF1 BKR POS2
φ
A/3P
— This setting selects the FlexLogic operand that represents the breaker normal-type auxiliary switch
contact (52/a). When using the single-pole breaker failure scheme, this operand represents the protected breaker auxiliary
switch contact on pole A. This can be a multiplied contact.
BF1 BREAKER TEST ON
— This setting is used to select the FlexLogic operand that represents the breaker in-service/out-of-
service switch set to the out-of-service position.
BF1 PH AMP HISET PICKUP
— This setting sets the phase current output supervision level. Generally this setting is to detect
the lowest expected fault current on the protected breaker, before a breaker opening resistor is inserted.
BF1 N AMP HISET PICKUP
— This setting sets the neutral current output supervision level. Generally this setting is to detect
the lowest expected fault current on the protected breaker, before a breaker opening resistor is inserted. Neutral current
supervision is used only in the three pole scheme to provide increased sensitivity. This setting is valid only for three-pole
breaker failure schemes.
BF1 PH AMP LOSET PICKUP
— This setting sets the phase current output supervision level. Generally this setting is to detect
the lowest expected fault current on the protected breaker, after a breaker opening resistor is inserted (approximately 90%
of the resistor current).
BF1 N AMP LOSET PICKUP
— This setting sets the neutral current output supervision level. Generally this setting is to 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 three-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 element 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 initiate 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 single-pole breaker failure schemes.