Secondary Injection Testing

Secondary Injection Testing is carried out to determine the correct operation of circuits connected to the secondary side of the control circuit transformers.

These include Protection relays, metering and low voltage devices such as shunt trips, sensors and transducers. The focus of Secondary Injection Testing relates to Protection relay testing and Circuit Breaker trip tests.

Protection Relay Testing is performed to ensure that the trip functions of a relay under various fault conditions are maintained within the manufacturer’s specification.

The testing of single phase and three phase relays include:

• Trip Timing checks as per settings
• Correct operation of Auxiliary contacts
• Alarm functions
• Polarity checks
• Physical conditions

We have test set OMICRON356 with additional equipment available via external hire partners. Unit is accompanied by a full Relay toolkit including specific manufacturer’s test blocks, test probes, resistors, multi-meters and various hand tools.

Circuit Breaker secondary injection testing is an alternative to the standard Primary Injection Testing. Secondary injection testing can be carried out if Primary Injection is not possible or only the trip function requires to be tested. These tests prove the operation of the trip units are within the manufacturer’s trip time curves.

Modern Circuit Breakers have test points located in the trip circuit to allow for manufacturer specific tests sets to be used to prove the trip circuits. These units simulate the trip circuit currents to ensure the trip units operate as intended. Older Circuit breaker designs can be the open wiring design type where the trip circuits are accessible and standard secondary injection test sets can be used.