A.6 Definition of the Active Power Measurement
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7UM62 Manual
C53000-G1176-C149-3
Table A-2 shows that the operating ranges in generator and motor operation are mir-
rored around the reactive power axis. The measured power values also result from the
above definition.
If, for instance, the forward power monitoring or the reverse power protection is to be
used in a synchronous motor, parameter
must be set to
Motor
. As a result, the actual active power (according to the above definition) is mul-
tiplied with –1. This means that the power diagram is mirrored around the reactive
power axis and that the interpretation of the active power changes. This effect must
be considered when evaluating the metered energy values.
If, for instance, positive power values are to be obtained in an asynchronous motor,
the current direction (parameter
0201
) must be reversed. Param-
eter
remains set to
Generator
. This means that because of
the generator reference-arrow system the earthing of the CTs that must be entered in
the device is the opposite of the actual earthing. This leads to results that are compa-
rable to those of a load reference-arrow system.
