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2 Functions
Table 2-13
The table 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 1108 ACTIVE POWER must be set to Motor.
This multiplies the actual active power (according to the above definition) with –1. This
means that the power diagram is symmetrical around the reactive power axis and the
interpretation of active power changes. This effect must be considered when evaluat-
ing the metered energy values.
If for instance positive power values are to be obtained with an asynchronous motor,
the current direction at the allocated CT set (e.g. parameter 210 CT Starpoint)
must be reversed. Parameter 1108 ACTIVE POWER remains in the default setting
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 comparable to those of a consumer reference-
arrow system.
214
Operating Ranges for Synchronous and Asynchronous Machines
Synchronous generator
Asynchronous generator
Synchronous motor
Asynchronous motor
7UM61 Manual
C53000-G1176-C127-3
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