GE Multilin C70 Capacitor Bank Protection and Control System 5-2275 SETTINGS 5.7 CONTROL ELEMENTS5• The current is initially interrupted.• 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 5–107: ALGORITHM ILLUSTRATION – STATE MACHINE TO DETECT RESTRIKEIn this way, a distinction is made between a self-extinguishing restrike and permanent breaker failure condition. The lattercan be detected by the breaker failure function or a regular instantaneous overcurrent element. Also, a fast succession ofrestrikes 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 musthave a valid CT bank assigned.• BREAKER RESTRIKE 1 PICKUP: This setting specifies the pickup level of the overcurrent detector in per-unit valuesof 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 mustbe logic “1” when breaker is open.• BRK RSTR 1 OPEN CMD: This setting assigns a FlexLogic operand indicating a breaker open command. It must belogic “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 belogic “1” when breaker is closed.Capacitor bankofflineCurrentinterruption(overcurrent)High-frequencyelevated currentRestrike detected:OP state assertedBreaker closeBreakercloseBreakercloseCapacitor bankonlineCurrentinterruption(overcurrent)Breaker opencommand or breakeropen state834768A1.CDR
