GE UR T60, Instruction Manual

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5-256 T60 Transformer Protection System GE Multilin
5.7 CONTROL ELEMENTS 5 SETTINGS
5
• 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 state machine diagram shown below.
Figure 5–143: 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.
• BRK RSTR 1 BRK OPEN : This setting assigns a FlexLogic™ operand indicating the open position of the breaker. It
must be logic “1” when breaker is open.
• BRK RSTR 1 OPEN CMD : This setting assigns a FlexLogic™ operand indicating a breaker open command. It must be
logic “1” when breaker is opened, either manually or from protection logic.
• BRK RSTR 1 CLS CMD : This setting assigns a FlexLogic™ operand indicating a breaker close command. It must be
logic “1” when breaker is closed.
Capacitor bank
offline
Current
interruption
(overcurrent)
High-frequency
elevated current
Restrike detected:
OP state asserted
Breaker close
Breaker
close
Breaker
close
Capacitor bank
online
Current
interruption
(overcurrent)
Breaker open
command or breaker
open state
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