Breaker Failure - GE D90 Plus Instruction Manual

CHAPTER 7: PROTECTION

Breaker failure

PLUS
D90 LINE DISTANCE PROTECTION SYSTEM – INSTRUCTION MANUAL
Source
Range: LINE (SRC 1), BKR 1 (SRC 2), BKR 2 (SRC 3)
Default: LINE (SRC 1)
This setting selects the signal source for the auxiliary overvoltage protection element.
Pickup
Range: 0.000 to 1.100 pu in steps of 0.001
Default: 0.300 pu
This setting specifies the auxiliary overvoltage pickup level in per-unit values.
Pickup Delay
Range: 0.00 to 600.00 seconds in steps of 0.01
Default: 1.00 seconds
This setting selects the minimum operating time of the auxiliary overvoltage element.
Reset Delay
Range: 0.00 to 600.00 seconds in steps of 0.01
Default: 1.00 seconds
This setting specifies the minimum reset time of the auxiliary overvoltage element.
Block
Range: any FlexLogic™ operand or shared operand
Default: Off
Assertion of the operand assigned to this setting blocks the auxiliary overvoltage
element.
Events
Range: Enabled, Disabled
Default: Disabled
This setting enables and disables the logging of auxiliary overvoltage events in the
sequence of events recorder.
The logic for the auxiliary overvoltage element is shown below. The logic is identical for all
auxiliary overvoltage elements.
Figure 187: Auxiliary overvoltage scheme logic
In general, a breaker failure scheme determines that a breaker signaled to trip has not
cleared a fault within a definite time, so further tripping action must be performed. Tripping
from the breaker failure scheme should trip all breakers, both local and remote, that can
supply current to the faulted zone. Usually operation of a breaker failure element will cause
clearing of a larger section of the power system than the initial trip. Because breaker
failure can result in tripping a large number of breakers and this affects system safety and
stability, a very high level of security is required.
GROUPED PROTECTION ELEMENTS
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