ABB Switzerland Ltd REG 316*4 1MRB520049-Uen / Rev. F
3-326
E. Setting instructions
The measurement function must be carefully set to obtain the
best accuracy. The following must be observed:
· C.t./v.t. input channel reference values
The reference values for the voltage and current input
channels must be set such that, when the rated values are
applied to the inputs, 1.000 UN and 1.000 IN are measured
by the function.
In most cases it will be possible to retain the default refer-
ence setting (1.000) for the c.t. and v.t. input channels. Note
that any changes made to the reference value of a three-
phase voltage or current I/P applies to all phases.
· “Angle” setting for phase error compensation
The parameter “Phase-angle” must be correctly set in order
to measure real and apparent power correctly. In most cases
it will be possible to retain the default reference setting of 0.0
degrees when measuring the phase-to-ground voltage and
current of the same conductor.
Other settings may be necessary in the following cases:
a) A phase-to-phase voltage is being measured, e.g. meas-
urement of the R phase current in relation to the R - S
voltage:
=> phase compensation: +30.0°
b) Compensation of c.t. and v.t. phase errors.
=> phase compensation: according to calibration,
e.g. (
-5.0°...+5.0°)
c) Change of measuring direction or correction of c.t. or v.t.
polarity.
=> phase compensation: +180.0° or
-180°
Where several of these factors have to be taken into consid-
eration, the phase compensation in all the cases must be
added and the resultant set.
The angles given apply for connection according to the
connections in Section 12.
· Power reference value “PN”
In most cases it will be possible to retain the default refer-
ence setting (1.000). Since the errors in the voltage and
current reference values add geometrically, a fine setting is
recommended to achieve the best possible accuracy.
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