Secondary Injection Test for Protection Relay
Secondary injection testing checks a protection relay by injecting current and voltage into its secondary inputs, simulating the signals a current or voltage transformer would deliver during a fault. It verifies relay settings and operating times without needing primary current, so it is the standard method for routine relay testing.
Relay test sets in the manufacturer's range cover single-phase, three-phase and six-phase injection. The TEST-750 covers single phase work; the TEST-330 covers three phase work with five voltage outputs; the TEST-630 covers six phase work for differential and distance protection. The test list for a three-phase set includes differential, distance, overcurrent, overvoltage, impedance, power direction, setting group, state sequence and fault waveform reproduction, among others.
A secondary injection test plan should list each protection function to be tested, the settings to be verified, the test currents and voltages, and the expected operating times. Record the injected values, the relay response, the operating time, and any setting changed during the test. A relay that passes at one setting but is used at another has not been tested; test at the settings actually in service.
Before ordering, confirm the relay types, the number of outputs needed, the test functions required, and the delivery terms. Ask for the current datasheet to be confirmed in writing before ordering.
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What to confirm before ordering
Before payment, confirm the model, the specification from the current datasheet, the quantity, the price, the lead time, and the delivery terms, in writing. Ask in your inquiry to confirm the payment terms, the trade terms, and the reply time you should expect, rather than assuming any of them. No price, minimum order or lead time figure is stated on this site.
Send an inquiry: include the model, the test or measurement requirement, and the quantity you need. Before payment, confirm the model, the specification from the current datasheet, the quantity, and the delivery terms.