Sensitive Ground-Fault Detection
Overview of Functions
2 functions are available for ground-fault detection: a directional one and a non-directional one.
The Directional sensitive ground-fault detection (ANSI 67Ns) serves:
•
For directional detection of permanent ground faults in isolated or resonant-grounded systems
•
For directional detection of fast extinguishing transient ground faults in isolated or resonant-grounded
systems
•
For determination of the faulty phase
•
For detection of high-impedance ground faults in effectively (solidly) or low-impedance (semi-solidly)
grounded systems
The Non-directional sensitive ground-fault detection (ANSI 51Ns) serves:
•
For ground-fault detection in isolated or resonant-grounded systems
•
For detection of high-impedance ground faults in effectively (solidly) or low-impedance (semi-solidly)
grounded systems
Structure of the Function
Directional Sensitive Ground-Fault Detection
The Directional sensitive ground-fault detection function can be used in protection function groups that
make current and voltage zero-sequence systems (3I0 and V0) available. The function comes factory-set with
a non-directional V0> stage with zero-sequence voltage/residual voltage, a directional 3I0> stage with cos
φ or sin φ measurement, and a directional transient ground-fault stage.
The following stages can be operated simultaneously within the function:
•
2 non-directional V0> stages with zero-sequence voltage/residual voltage
•
4 directional 3I0> stages with cos φ or sin φ measurement
•
2 directional transient ground-fault stages
•
4 directional 3I0> stages with φ(V0, 3I0) measurement
•
4 directional Y0> stages with G0 or B0 measurement (admittance method)
•
4 directional stages with phasor measurement of a harmonic
•
4 non-directional 3I0> stages
•
2 non-directional Y0> stages
•
2 non-directional pulse-pattern detection stages
The general functionality works across stages on the function level.
The group-indications output logic generates the following group indications of the entire function by the
logical OR from the stage-selective indications:
•
Pickup
•
Operate indication
6.15
6.15.1
6.15.2
Protection and Automation Functions
6.15 Sensitive Ground-Fault Detection
562 SIPROTEC 5, Overcurrent Protection, Manual
C53000-G5040-C017-8, Edition 07.2017
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