VAMP 59 - 4 Measurement Functions; Measurement Accuracy

Technical description
4 Measurement functions
4.1 Measurement accuracy
VM59.EN001
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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.