2SY212-S Synchronism Check Relay


The 2SY212 synchronism check relay is designed to measure the phase angle between the monitored single phase voltages on the line & bus sides of a circuit breaker & verify that this angle is less than setting. If the measured angle has met this criteria for the time period defined by setting & the voltage magnitudes meet the criteria established by the Live Line/Bus & U/V Line/Bus settings, the output relay will be energised & the breaker permitted to close. Resetting will occur if either the phase angle or voltage magnitude stray outside the pre-set limits or if the sync check enable input is de-energised. Front panel LED’s provide visual indication of relay status & sync check function. Bus or Line U/V, Differential Voltage and Frequency Slip Close block functionality together with flexible synchronism check bypass logic caters for a diverse range of applications.

The standard Micro MATRIX human machine interface (HMI) is combined with fully solid state measuring circuitry to provide high accuracy, simple set up & flexible operation. Self-monitoring is carried out by hardware & software watchdogs. High contact rating output relays are employed. A USB programming port is provided for ease of establishing relay settings using a PC. Front panel mounted LED’s provide visual indication of relay status & sync check function.


  • Synchronism Check (25)
  • Adjustable phase angle and time delay
  • Flexible Live and Dead Voltage configuration
  • Bus or Line U/V Close Block
  • Voltage Differential Close Block
  • Frequency Slip Close Block
  • Flexible Synchronism Check Bypass Logic
  • Manual Safe to Close Feature





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