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The control module is able to measure three
phase currents, active and reactive power and
energy. The phase currents are measured via the
1 A or 5 A current inputs of the feeder terminal.
For measuring active and reactive power the
module includes two mA-inputs. The output
signals of external measuring transducers are
wired to these two inputs. Energy can be meas-
ured in two ways; by using input 7 as a pulse
counter or integrating the measured power. If
the pulse counter is used an external energy
meter with a pulse output is needed.
Phase currents
The three phase currents are displayed locally
and transferred in actual kiloamperes via the
serial bus. To be able to do this the current
measurement must be scaled. The scaling is
based on the entered rated current of the pri-
mary side of the primary current transformer.
Example 12: Scaling of the phase current meas-
urement.
The nominal current of the primary side of the
primary current transformers is 400 A. The
current must be given in amperes. The scaling
factor is 400.00.
>99WS9:400.00:XX
; Set scaling factor S9 to 400.00
>99WV151:1:XX
; Store the programmed parameters
The scaling factor can be programmed within
the range 0.00…10000.00. The default value of
variable S9 after factory testing is 200.00.
Active and reactive power
The value of the active power is displayed locally
and transferred in actual megawatts via the serial
bus. Correspondingly the value of the reactive
power is displayed locally and transferred in
actual megavars via the serial bus. Both negative
and positive power values can be measured.
The power measurement is enabled or disabled
by means of parameter S91. As a default power
measurement is disabled (S91=0). The input
signal range of the mA-inputs is -20…20 mA.
The following setting parameters are used for
scaling the inputs:
S12 = Low limit of the mA signal related to
active power, sign
S13 = High limit of the mA signal related to
active power, sign
S14 = Low limit of the mA signal related to
reactive power, sign
S15 = High limit of the mA signal related to
reactive power, sign
S16 = Value of active power corresponding to
the mA signal at low limit, sign
S17 = Value of active power corresponding to
the mA signal at high limit, sign
S18 = Value of reactive power corresponding to
the mA signal at low limit, sign
S19 = Value of reactive power corresponding to
the mA signal at high limit, sign
After the power measurement has been enabled
the low and high limits of the mA signals are
given and then the corresponding values of
active and reactive power.
Scaling of
measurements
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