Ground Fault Check - Siemens siprotec SJ62 User Manual

3 Mounting and Commissioning

3.3.11 Ground Fault Check

Ungrounded
Systems
433
Figure 3-37 Measuring voltages for the synchro-check
The ground fault test is only necessary if the device is connected to an isolated or res-
onant-grounded system and the ground fault detection is applied.
The device must thus have been preset during configuration of the device functions to
Gnd Fault 131
(address
section is not relevant.
The primary check serves to find out the correct polarity of the transformer connec-
tions for the determination of the ground fault direction.
DANGER!
Energized equipment of the power system ! Capacitive coupled voltages at discon-
nected equipment of the power system !
Non-observance of the following measure will result in death, severe personal injury
or substantial property damage.
Primary measurements must only be carried out on disconnected and grounded
equipment of the power system !
Using the primary ground fault method a most reliable test result is guaranteed. There-
fore please proceed as follows:
• Isolate the line and ground it on both ends. During the whole testing procedure the
line must be open at the remote end.
• Make a test connection between a single phase and ground. On overhead lines it
can be connected anywhere, however, it must be located behind the current trans-
formers (looking from the busbar of the feeder to be checked). Cables are grounded
on the remote end (sealing end).
• Remove the protective grounding of the line.
• Connect a circuit breaker to the line end that is to be tested.
• Check the direction indication (LED if allocated)
Disabled
) not equal to
If none of this is the case, this sub-
.
SIPROTEC 4, 7SJ62/63/64 Handbuch
C53000-G1140-C147-A, Edition 07.2015
Sens.