Siemens 7SJ85 - Page 1376

For directional testing, the Directional sensitive ground-fault detection function (67Ns) is configured and a
directional stage is switched on. For example, the directional 3I0> stage with cos φ or sin φ measurement.
The most reliable test is the one with a primary ground fault. Proceed as follows:
²
Isolate the line and ground it on both sides; on the farthest line end it must remain open during the
entire test.
²
Place a 1-phase ground fault bridge on the line. For overhead lines, this can be done at an arbitrary loca-
tion, in any case behind the current transformer (as seen from the busbar of the feeder to be tested). For
cables, the grounding is done on the farthest end (sealing end).
²
Remove the protective grounding from the line.
²
Switch on the circuit breaker on the line to be tested.
²
Check direction indicator (LED if routed).
² Check the indication
(_:302) Ground fault in the ground-fault log or fault log with regard to its
direction. The indication
(_:302) Ground fault forward must be logged as direction information.
If backward is determined as the direction, either with the current connections or the voltage connec-
tions, there is an inversion in the neutral path. For the display unknown , the ground current is probably
too low.
²
Switch the line off and ground it.
This completes the test.
Functional Tests
11.3 Direction Test of Ground Quantities for Directional Ground-Fault Functions
1376 SIPROTEC 5, Overcurrent Protection, Manual
C53000-G5040-C017-8, Edition 07.2017