GE C70 Instruction Manual page 373

CHAPTER 5: SETTINGS
• The breaker status is open
• An elevated high frequency current condition occurs and the current subsequently drops out again
The algorithm is illustrated in the following state machine diagram.
Figure 5-132: 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 current.
BREAKER RESTRIKE 1 PICKUP
BREAKER RESTRIKE 1 RESET DELAY
picked up for only 1/8th of the power cycle.
— Assigns a FlexLogic operand indicating the open position of the breaker. It must be logic "1" when
BRK RSTR 1 BRK OPEN
the breaker is open.
— Assigns a FlexLogic operand indicating a breaker open command. It must be logic "1" when the
BRK RSTR 1 OPEN CMD
breaker is opened, either manually or from protection logic.
— Assigns a FlexLogic operand indicating a breaker close command. It must be logic "1" when the
BRK RSTR 1 CLS CMD
breaker is closed.
C70 CAPACITOR BANK PROTECTION AND CONTROL SYSTEM – INSTRUCTION MANUAL
Capacitor bank
offline
Current
interruption
(overcurrent)
High-frequency
elevated current
Current
interruption
(overcurrent)
Restrike detected:
OP state asserted
— 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
Breaker open
command or breaker
open state
Breaker
close
Capacitor bank
online
Breaker
close
Breaker close
834768A1.CDR
CONTROL ELEMENTS
5
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