GE C70 Instruction Manual page 481

CHAPTER 5: SETTINGS
5.8.10.2 Breaker arcing current
SETTINGS  CONTROL ELEMENTS  MONITORING ELEMENTS  BREAKER 1(3) ARCING CURRENT
 BREAKER 1
 ARCING CURRENT
There is one breaker arcing current element available per CT bank, with a minimum of two elements. This element
calculates an estimate of the per-phase wear on the breaker contacts by measuring and integrating the current squared
passing through the breaker contacts as an arc. These per-phase values are added to accumulated totals for each phase
and compared to a programmed threshold value. When the threshold is exceeded in any phase, the relay can set an
output operand to "1." The accumulated value for each phase can be displayed as an actual value.
The operation of the scheme is shown in the following logic diagram. The same output operand that is selected to operate
the output relay used to trip the breaker, indicating a tripping sequence has begun, is used to initiate this feature. A time
delay is introduced between initiation and the starting of integration to prevent integration of current flow through the
breaker before the contacts have parted. This interval includes the operating time of the output relay, any other auxiliary
relays, and the breaker mechanism. For maximum measurement accuracy, measure the interval between change-of-state
of the operand (from 0 to 1) and contact separation for the specific installation. Integration of the measured current
continues for 100 ms, which is expected to include the total arcing period.
The feature is programmed to perform fault duration calculations. Fault duration is defined as a time between operation of
the disturbance detector occurring before initiation of this feature, and reset of an internal low-set overcurrent function.
Correction is implemented to account for a non-zero reset time of the overcurrent function.
Breaker arcing currents and fault duration values are available under the
menus.
BREAKER 1(3)
— Select the same output operands that are configured to operate the output relays used to trip the
BKR 1 ARC AMP INT-A(C)
breaker. In three-pole tripping applications, configure the same operand to initiate arcing current calculations for poles A,
B, and C of the breaker. In single-pole tripping applications, configure per-pole tripping operands to initiate the calculations
for the poles that are actually tripped.
— This setting is used to program the delay interval between the time the tripping sequence is
BKR 1 ARC AMP DELAY
initiated and the time the breaker contacts are expected to part, starting the integration of the measured current.
— Selects the threshold value above which the output operand is set.
BKR 1 ARC AMP LIMIT
C70 CAPACITOR BANK PROTECTION AND CONTROL SYSTEM – INSTRUCTION MANUAL
BKR 1 ARC AMP

FUNCTION: Disabled
BKR 1 ARC AMP

SOURCE: SRC 1
BKR 1 ARC AMP INT-A:

Off

BKR 1 ARC AMP INT-C:

Off
BKR 1 ARC AMP

DELAY: 0.000 s
BKR 1 ARC AMP LIMIT:

1000 kA2-cyc
BKR 1 INTERRUPTION

RATING: 31.5 kA
BKR 1 CLR ARC AMPS:

Off
BKR 1 ARC AMP BLOCK:

Off
BKR 1 ARC AMP

TARGET: Self-reset
BKR 1 ARC AMP

EVENTS: Disabled
Range: Disabled, Enabled
Range: SRC 1, SRC 2, SRC 3, SRC 4, SRC 5, SRC 6
Range: FlexLogic operand
Range: FlexLogic operand
Range: 0.000 to 65.535 s in steps of 0.001
2
Range: 0 to 50000 kA -cycle in steps of 1
Range: 0.0 to 100.0 kA in steps of 0.1
Range: FlexLogic operand
Range: FlexLogic operand
Range: Self-reset, Latched, Disabled
Range: Disabled, Enabled
ACTUAL VALUES  RECORDS  MAINTENANCE 
CONTROL ELEMENTS
5
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