Circuit Breaker Operation Time (In-Service) (GIS)

In-service testing methods First trip and Voltage Based Timing (VTM) show degradation accumulated during long idle times better than their off-service counterparts because to prepare a breaker for off-service testing, it has to be operated at least once. For the First trip test method connections are made at the trip coils and the CT’s secondary side. For the Voltage Based Timing (VTM) measurement method, the connections are made at the trip cols and the VT’s secondary side. These test methods are very well suited to detected degraded lubricants, contaminated surfaces or corroded mechanical elements.

Some medium-voltage GIS types have their main contacts sealed for lifetime. Thus, they cannot be accessed easily by the test device. Thus, Voltage-based Timing Measurement (VTM) is the only measurement method available to measure the timing of such medium voltage GIS types. The measurement method can be applied to all breakers with a voltage detection system (VDS) that makes the main voltages accessible.