Chapter 21 - Commissioning Instructions
If the Local Values cell is set to Secondary, the values displayed should be equal to the applied secondary
voltage. The values should be within 1% of the applied secondary voltages. However, an additional allowance must
be made for the accuracy of the test equipment being used.
If the Local Values cell is set to Primary, the values displayed should be equal to the applied secondary voltage
multiplied the corresponding voltage transformer ratio set in the CT & VT RATIOS column. The values should be
within 1% of the expected values, plus an additional allowance for the accuracy of the test equipment being used.
ON-LOAD DIRECTIONAL TEST
This test ensures that directional overcurrent and fault locator functions have the correct forward/reverse
response to fault and load conditions. For this test you must first know the actual direction of power flow on the
system. If you do not already know this you must determine it using adjacent instrumentation or protection
For load current flowing in the Forward direction (power export to the remote line end), the A Phase Watts
cell in the MEASUREMENTS 2 column should show positive power signing.
For load current flowing in the Reverse direction (power import from the remote line end), the A Phase
Watts cell in the MEASUREMENTS 2 column should show negative power signing.
This check applies only for Measurement Modes 0 (default), and 2. This should be checked in the MEASURE'T SETUP column
(Measurement Mode = 0 or 2). If measurement modes 1 or 3 are used, the expected power flow signing would be opposite to
that shown above.
In the event of any uncertainty, check the phase angle of the phase currents with respect to their phase voltage.