GE M60 Instruction Manual page 519

CHAPTER 5: SETTINGS
breaker restrike condition is declared in the corresponding phase and the
period of time. The user can add counters and other logic to facilitate the decision making process as to the appropriate
actions upon detecting a single restrike or a series of consecutive restrikes.
A restrike event (FlexLogic operand) is declared if all of the following hold:
• The current is initially interrupted
• The breaker status is open
• An elevated high frequency current condition occurs (if the
the condition is bypassed), and
• The current subsequently drops out again
The algorithm is illustrated in the following state machine diagram.
Figure 5-176: Algorithm illustration of state machine to detect restrike
In this way, a distinction is made between a self-extinguishing restrike and permanent breaker failure condition. The latter
can be detected by the breaker failure function or a regular instantaneous overcurrent element. Also, a fast succession of
restrikes is picked up by breaker failure or instantaneous overcurrent protection.
The following settings are available for each element.
BREAKER RESTRIKE 1 FUNCTION
— Blocks operation of the breaker restrike detection element.
BRK RSTR 1 BLOCK
— Selects the source of the current for this element. This source must have a valid CT bank
BREAKER RESTRIKE 1 SOURCE
assigned.
— Specifies the pickup level of the overcurrent detector in per-unit values of CT nominal
BREAKER RESTRIKE 1 PICKUP
current.
BREAKER RESTRIKE 1 RESET DELAY
picked up for only 1/8th of the power cycle.
M60 MOTOR PROTECTION SYSTEM – INSTRUCTION MANUAL
— Enables and disables operation of the breaker restrike detection element.
— Specifies the reset delay for this element. When set to "0 ms," then FlexLogic operand is
operand asserts for a short
BRK RESTRIKE 1 OP
BREAKER RESTRIKE 1 HF DETECT
CONTROL ELEMENTS
setting is Enabled, otherwise
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