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4.2 RMS values
4 Measurement functions
Technical description
138
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VM50.EN004
Voltage input U
The usage of voltage inputs depends on the configuration
parameter voltage measurement mode. For example, U is the
zero sequence voltage input U
0
if the mode “U
0
” is selected.
Measuring range
0 – 160 V
Inaccuracy
0.5 % or 0.3 V
The specified frequency range is 45 Hz – 65 Hz.
Residual current input I
0
Measuring range
0 – 10 xI
n
Inaccuracy I
1.5 xI
n
0.3 % of value or 0.2 % of I
n
I > 1.5 xI
n
3 % of value
The specified frequency range is 45 Hz – 65 Hz.
The rated input I
n
is 5A, 1 A or 0.2 A. It is specified in the order
code of the relay.
Frequency
Measuring range
16 Hz – 75 Hz
Inaccuracy
10
mHz
The frequency is measured from current signals.
THD and harmonics
Inaccuracy
I, U > 0.1 PU
2 % units
Update rate
Once a second
The specified frequency range is 45 Hz – 65 Hz.
4.2.
RMS values
RMS currents
The device calculates the RMS value of each phase current. The
minimum and the maximum of RMS values are recorded and
stored (see chapter 4.5).
2
15
2
2
2
1
...
f
f
f
rms
I
I
I
I
RMS voltages
The device calculates the RMS value of each voltage input. The
minimum and the maximum of RMS values are recorded and
stored (see chapter 4.5).
2
15
2
2
2
1
...
f
f
f
rms
U
U
U
U