Testing & Commissioning
Secondary Injection Testing
Secondary injection testing injects test currents and voltages at the relay itself, proving the protection picks up, times and trips exactly as its settings intend, without energising the primary circuit.
Secondary injection testing applies test currents and voltages directly at the protection relay, rather than through the primary circuit. It confirms the relay picks up at the right value, times correctly and trips as intended, without needing to energise the primary equipment or create a real fault.
It is the difference between believing the protection is configured correctly and having verified it.
What secondary injection testing covers
- Pickup value verification against applied settings
- Timing verification across the protection curve
- Trip output confirmation to the switching mechanism
- Earth fault and sensitive earth fault element testing
- Reclose sequence verification
- Test record documenting injected values and measured response
What matters in practice
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Tests the settings, not just the relay
A functioning relay with wrong settings fails exactly as badly as a faulty one. Injection testing verifies the configuration that was actually applied.
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Multiple points on the curve
Testing at a single current value confirms very little. Verification across the curve is what demonstrates the timing characteristic is correct.
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Measured accuracy
The reclosers we work with specify phase current measurement accurate to the greater of one percent or two amps, which is the benchmark test results are read against.
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Documented results
Injected values and measured response are recorded, so a future engineer has evidence rather than an assurance.
Related services
Need protection verified?
Tell us what you need and where the site is, and we will scope the work and quote it.