GE C60 Instruction Manual page 384

5.7 CONTROL ELEMENTS
tion is declared in the corresponding phase and 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
wise the condition is bypassed), and
• The current subsequently drops out again
The algorithm is illustrated in the state machine diagram shown below.
5
Figure 5–110: ALGORITHM ILLUSTRATION – 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 will be picked up by breaker failure or instantaneous overcurrent protection.
The following settings are available for each element.
• BREAKER RESTRIKE 1 FUNCTION: This setting enable and disables operation of the breaker restrike detection ele-
ment.
• BRK RSTR 1 BLOCK: This setting is used to block operation of the breaker restrike detection element.
• BREAKER RESTRIKE 1 SOURCE: This setting selects the source of the current for this element. This source must
have a valid CT bank assigned.
• BREAKER RESTRIKE 1 PICKUP: This setting specifies the pickup level of the overcurrent detector in per-unit values
of CT nominal current.
• BREAKER RESTRIKE 1 RESET DELAY: This setting specifies the reset delay for this element. When set to "0 ms",
then FlexLogic operand will be picked up for only 1/8th of the power cycle.
5-248
operand is asserted for a short period of time. The
BRK RESTRIKE 1 OP
BREAKER RESTRIKE 1 HF DETECT
C60 Breaker Protection System
5 SETTINGS
setting is Enabled, other-
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