janitza UMG 96-S2, User Manual And Technical Data

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13.8 Checking the individual powers
If an incorrect phase conductor (phase) is
assigned to a current transformer, the associated
power is incorrectly measured and displayed.
The phase conductor and current transformer
are correctly assigned on the device if there is no
voltage present between the phase conductor
and the associated current transformer (primary).
To ensure that a phase conductor is assigned
to the correct current transformer at the voltage
measurement input, the respective current
transformer can be short circuited on the
secondary side. The apparent power displayed
by the device must then be zero in this phase
conductor (phase).
If the apparent power is displayed correctly, but
the active power is displayed with a negative
(“-”) sign, then the current transformer terminals
are reversed or power is being delivered to the
energy supply company.
13.9 Checking the sum powers
If all voltages, currents and powers are correctly
displayed for the respective phase conductor,
the sum powers measured by the device are
also correct. For confirmation, compare the sum
powers measured by the device with the work of
the active and reactive power counter located in
the supply.