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Circuit Breaker Testing

Circuit Breaker Testing and Anlysis

We provide

  • commissioning works for medium and high voltage circuit breakers
  • complete maintenance and preventive program
  • services in case of damage, malfunctions or any other circumstance  

All the above are provided according to the latest applicable international standards and will be followed by relevant test reports.

  • Insulation resistance measurements (IR – DAR – PI)

These are cornerstone tests for CB condition monitoring. These tests indicate the insulating quality of a dielectric by applying a DC voltage and measuring the current flow to present the insulation value in ohms and trend this value over a time interval of 10 minutes. ATE uses a series of testers (up to 70kV) to perform the measurements




  •  Capacitance and tan δ measurements 

 The measurement and trending of the dielectric loss angle of circuit breaker bushings is an important tool in the condition monitoring regime. The values and the trend will show degradation of the insulation and can be used in predictive assessment to determine the best time for costly maintenance. ATE uses the MEGGER DELTA 4000 test unit to perform measurements to the highest accuracy.


  •  Time test 

The time that a CB takes to operate is very important as it needs to be fast enough to clear the fault rapidly and to fit within the grading allowances for the protection scheme. Another factor that is not as widely known is the importance of the velocity of the contacts at the point that the primary contacts part as this determines how effectively the CB will break the current. To determine the velocity, acceleration and deceleration of the contacts through the stroke, a time/travel test needs to be performed. ATE uses SA100 and PME-500-TR units to perform the following operations

  • CLOSE operation
  • OPEN operation
  • CLOSE - OPEN operation



  • Contact resistance measurements

Contact resistance measurement is a simple and effective test that can determine whether high resistances are present in the primary contact and HV connections that could to heating and failures. ATE uses micro- ohmmeter WRM-40 manufactured by VANGUARD INSTRUMENTS Inc.