Interconnection protective devices that have not previously been tested as part of the interconnection system with their associated instrument transformers or that are wired in the field shall be given an on-load test during commissioning. This test will verify proper wiring, polarity, sensing signals, CT/PT ratios and operation of the measuring circuits. The on-load test shall be made with the power system energized and carrying a known level of voltage and current. The magnitude and phase angle of each alternating-current (AC) voltage and AC current connected to the protective device will be measured and the results compared to expected values.
For protective devices with built-in metering functions that report current and voltage magnitudes and phase angles, or magnitudes of current, voltage, and real and reactive power, the metered values can be compared to the expected values. Otherwise, calibrated portable ammeters, voltmeters and phase-angle meters shall be used.