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Technical description
4 Measurement functions
4.1 Measurement accuracy
VM59.EN001
VAMP 24h support phone +358 (0)20 753 3264
131
4.
Measurement functions
All the direct measurements are based on fundamental
frequency values. Most protection functions are also based on
the fundamental frequency values.
The figure shows a current waveform and the corresponding
fundamental frequency component f1, second harmonic f2 and
rms value in a special case, when the current deviates
significantly from a pure sine wave.
Figure 4-1 Example of various current values of a transformer inrush
current.
4.1.
Measurement accuracy
Phase current inputs I
L1
, I
L2
, I
L3
Measuring range
0.025 – 250 A
Inaccuracy
I
7.5 A
0.5 % of value or 15 mA
I > 7.5 A
3 % of value
The specified frequency range is 45 Hz – 65 Hz.
Residual current input I
0
Measuring range
0.003 – 5 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.
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.
Содержание VAMP 59
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