Breaker Failure - GE D90 Plus Instruction Manual

GROUPED PROTECTION ELEMENTS

Breaker failure

276
Events
Range: Enabled, Disabled
Default: Disabled
This setting enables and disables the logging of auxiliary overvoltage events in the
sequence of events recorder.
The figure shows the logic for the auxiliary overvoltage element. The logic is identical for all
auxiliary overvoltage elements.
Figure 239: Auxiliary overvoltage 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 needs to trip all breakers, both local and remote, that can
supply current to the faulted zone. Usually operation of a breaker failure element causes
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.
Two schemes are provided: one for three-pole tripping only and one for three pole plus
single-pole operation. The philosophy used in these schemes is identical. The operation of
a breaker failure element includes three stages: initiation, determination of a breaker
failure condition, and output.
Figure 240: Breaker failure main path sequence
The current supervision elements reset in less than 0.7 of a power cycle up to a multiple of
pickup of 100 (threshold set at 0.01 of the actual fault current), shown as follows.
PLUS
D90 LINE DISTANCE PROTECTION SYSTEM – INSTRUCTION MANUAL
CHAPTER 7: PROTECTION