Check synchronising

Check Synchronising – Reyrolle 7SR157

Reyrolle 7SR157

The Reyrolle 7SR157 Argus is a combined check and system synchronising relay designed to carry out controlled closing of a circuit breaker using measurements of the line and bus voltages.

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Features & functions

Check synchronising Reyrolle 7SR157


The relay will prevent the closure of a circuit breaker if the differences in phase angle, slip frequency or magnitude of the voltage falls outside prescribed limits.


If the parameters are within limits, the relay will issue an output which can be used to close the circuit breaker directly or in conjunction with an auto-reclose scheme.


Housed in a 4U high, size E4 case, the relay provides instrumentation and fault data with integrated input and output logic, data logging and fault reports. Communication access to the relay functionality is via a front USB port for local PC connection or rear electrical RS485 port for remote Connection.



  • Undervoltage detector (25)

  • Differential-voltage detector (25)

  • Voltage levels (live and dead status) (25)

  • Close-circuit supervision (74)

  • VT Fail (60)


  • Voltage trim (magnitude and phase) (25)

  • System-split detector (25)

  • Check synchronizing (25)

  • Check synchronizing close guard (25)

  • System synchronizing (25)

  • Close on zero synchronizing (25)

  • System-split lockout (25)

  • Synchronizing bypass (25)


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