Directional Ground Fault (Compensated/Resonant-Grounded); Directional Ground Fault (In Isolated Electrical Power Systems) - Siemens SICAM Manual

Directional Ground Fault (Compensated/Resonant-Grounded)

4.1.17
In the compensated/resonant-grounded system, the Petersen coil is configured to match the capacitive
charging currents, such that when a ground fault occurs, a negligible fault current flows. The characteristic
angle is set to 0°. A boundary of +90° is used to detect the direction of the resistive component within residual
currents.
With the cos φ method, the watt-metric residual current is calculated in case of a fault. This method of deter-
mining the ground-fault detection is implemented in the watt-metric method. For more information about the
watt-metric method, refer to
In the vector method, the ground-fault detection occurs if the total current I
The device calculates the active power of the zero sequence (P0) and if the value is falling in the 1st and the
4th quadrant, then the direction is forward. If the active power of the zero sequence (P0) is falling in the 2nd
and 3rd quadrant, then the direction is shown as reverse.
For more information about directional ground-fault parameters (compensated/resonant-grounded), see
Table A-3 and refer to the Fault Parameter > Ground-Fault Detection > Neutral-point Treatment menu.
[dw_sfcm-grndflt-comp-res, 1, en_US]
Figure 4-11
NOTE
i
i
The undetermined area for the device MLFB 6MD2321-1AA00-1AA0 is 10° and the respective angles
change accordingly.
The undetermined area for the device MLFB 6MD2322-1AA00-1AA0 is 20° and the respective angles
change accordingly.
4.1.18

Directional Ground Fault (in Isolated Electrical Power Systems)

During ground fault on the isolated distribution system, no fault path is detected and subsequently no fault
current flows. The phase-to-neutral capacitive charging current of the healthy phases for the entire system is
supplied through the fault path. This produces a current that is used to detect the presence of the ground
fault. It appears as a residual current which lags the residual voltage by 90°. The characteristic angle is -90°.
The device calculates the reactive power of the zero sequence (Q0). If the value is falling in the 1st and the
2nd quadrant, then the direction is reverse. If the reactive power of the zero sequence (Q0) is falling in the 3rd
and 4th quadrant, then the direction is shown as forward.
For more information about directional ground-fault parameters (isolated grounded), see
to the Fault Parameter > Ground-Fault Detection > Neutral-point Treatment menu.
SICAM, Feeder Condition Monitor, Manual
E50417-H8940-C580-A4, Edition 03.2019
4.1.20 Ground-Fault Detection with Cos φ/Sin φ
Directional Ground Fault (Compensated/Resonant-Grounded) for Vector Method
Device Functions
4.1 Description
Measurement.
> is exceeded.
N
Table A-3 and refer
43