Secondary injection test set
Updated 2026-10-27
Data records
- The same set can inject on the secondary side of a current transformer to measure ratio, polarity, burden impedance and the excitation curve, applying a voltage to the secondary winding and measuring the resulting voltage on the primary side.
- The set combines an adjustable current source, alternating and direct voltage sources, a variable-frequency generator, a phase angle shifter and a battery simulator for the relay's auxiliary supply, stores settings and results, and shows the injected current and voltage waveforms in an oscilloscope view.
- Because secondary injection currents are far lower than primary injection currents, the sets are compact and portable, and a built-in control panel lets the main tests be run without a computer and with little training.
- Pickup is found by ramping the injected quantity; where a high-set overcurrent element would be overloaded by a sustained current, short pulses of increasing amplitude (pulse ramping) locate the pickup point while protecting the thermal rating of the relay.
- A secondary injection test set injects currents and voltages at the level of the relay or trip-unit secondary circuit, so that pickup, operating time and characteristics are checked without the high primary currents that the instrument transformers would otherwise supply.
- Secondary injection verifies the relay or trip unit alone and tells nothing about the current transformer or the wiring between it and the relay, so primary injection remains the full-path commissioning test while secondary injection serves routine maintenance.
- A single-phase set provides one current output, one voltage output and one binary input for the trip contact; virtually all single-phase protection can be tested, three-phase protection is tested one phase at a time, and a built-in capacitor gives the phase shift needed for directional relays.
Elsewhere in the family
- Trip Unit Secondary Injection related entry on Circuit Breaker Reference
- Protective Relay Element Tests related entry on Protective Relay Reference
Sources
- Doble product page, T 1000 PLUS secondary injection relay test set, web page edition, Doble. Held as: Public page. Publisher page
- Megger application page, Multi-phase relay testers for quick fault verification, web page edition, Megger. Held as: Public page. Publisher page
- Megger application page, Primary Injection Testing Solutions, web page edition, Megger. Held as: Public page. Publisher page
- Megger product page, SVERKER 650 relay and substation test system, web page edition, Megger. Held as: Public page. Publisher page
Changelog (15 entries)
| Date | Revision | Change |
|---|---|---|
| 2026-10-27 | created (instr.secondary-injection-test-set.ct-checks) | |
| 2026-10-27 | review_status unreviewed -> software_reviewed (instr.secondary-injection-test-set.ct-checks) | |
| 2026-10-27 | created (instr.secondary-injection-test-set.outputs-and-measurement) | |
| 2026-10-27 | review_status unreviewed -> software_reviewed (instr.secondary-injection-test-set.outputs-and-measurement) | |
| 2026-10-27 | created (instr.secondary-injection-test-set.portability) | |
| 2026-10-27 | review_status unreviewed -> software_reviewed (instr.secondary-injection-test-set.portability) | |
| 2026-10-27 | created (instr.secondary-injection-test-set.pulse-ramping) | |
| 2026-10-27 | review_status unreviewed -> software_reviewed (instr.secondary-injection-test-set.pulse-ramping) | |
| 2026-10-27 | created (instr.secondary-injection-test-set.purpose) | |
| 2026-10-27 | revised (instr.secondary-injection-test-set.purpose) | |
| 2026-10-27 | review_status unreviewed -> software_reviewed (instr.secondary-injection-test-set.purpose) | |
| 2026-10-27 | created (instr.secondary-injection-test-set.scope-limit) | |
| 2026-10-27 | review_status unreviewed -> software_reviewed (instr.secondary-injection-test-set.scope-limit) | |
| 2026-10-27 | created (instr.secondary-injection-test-set.single-phase-set) | |
| 2026-10-27 | review_status unreviewed -> software_reviewed (instr.secondary-injection-test-set.single-phase-set) |
Cite this page
Cite the governing standard for the fact itself; cite this page as the finding aid.
"Secondary injection test set." Test Instrument Reference. 2026-10-27. https://www.testinstrumentreference.com/instruments/secondary-injection-test-set/.
Test Instrument Reference, Secondary injection test set (Oct. 27, 2026), https://www.testinstrumentreference.com/instruments/secondary-injection-test-set/.
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title = {Secondary injection test set},
howpublished = {\url{https://www.testinstrumentreference.com/instruments/secondary-injection-test-set/}},
organization = {Test Instrument Reference},
publisher = {Test Instrument Reference},
year = {2026},
note = {last substantive change 2026-10-27}
}{{cite web |title=Secondary injection test set |website=Test Instrument Reference |publisher=Test Instrument Reference |url=https://www.testinstrumentreference.com/instruments/secondary-injection-test-set/ |date=2026-10-27 |access-date=}}