ABB Relion 670 series, Technical Manual

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Trip time
Fault resistance
R
Trip
R
Alarm
IEC11000002-1-en.vsd
10 FilterLength
×
2 FilterLength
×
IEC11000002 V1 EN-US
Figure 220: Trip time characteristic as function of fault resistance
A third high level step for the detection of excitation system ground faults on the AC side of the
excitation rectifier is available. This step uses the network frequency (50 or 60 Hz) for the
evaluation. If a ground fault occurs at the AC side of the excitation system rectifier, there is a
fundamental frequency component at the measured voltage and current injection points.
The third high level step is not applicable if mixed signals are used, that is when the REX060 is
used for both rotor and stator ground fault protection and only two, instead of four, analog inputs
on the IED are used.
7.13.9 Technical data
GUID-FFB37FA4-5C9D-477D-9ACF-8A39A4B30649 v3
Table 187: ROTIPHIZ technical data
Function Range or value Accuracy
Fault resistance sensitivity Can be reached 500 kΩ
Typically 50 kΩ
Injection frequency (75.000 - 250.000) Hz ±0.1 Hz
Trip limit of fault resistance (100 - 100000)Ω 5% of 1 kΩ at R
f
≤ 1 kΩ
5% of set value at 1 kΩ < R
f
≤ 20 kΩ
10% of set value at R
f
> 20 kΩ
Alarm limit of fault resistance (100 - 1000000)Ω 5% of 1 kΩ at R
f
≤ 1 kΩ
5% of 10 kΩ at 1 kΩ < R
f
≤ 20 kΩ
10% of set value at 20 kΩ < R
f
≤ 200 kΩ
Table continues on next page
Section 7 1MRK 502 066-UUS B
Impedance protection
408
Technical manual