Issue:
The P3 relay does not show frequency readings during a real or virtual injection test.
Product:
PowerLogic™ P3 Relay
Environment:
Testing scenario using virtual or secondary voltage injection.
Cause:
The frequency is not measured if:
- The maximum of the three phase-to-phase or phase-to-neutral voltages is less than 5.5 × (VT primary / VT secondary) (primary voltage reference).
- The secondary voltage injection is less than 5.5 V.
This is a design condition to ensure accurate frequency measurement.
Resolution:
Increase the magnitude of the injected voltage during the virtual injection test. After raising the voltage above the required threshold, the frequency readings will appear as expected.
