Fault Log and Fault Recording
You can select between the ground-fault log without fault recording or the normal fault log with fault
recording. If you set the parameter Operate & flt.rec. blocked to yes, the operate of the stage and
fault recording are blocked and the information automatically appears in the ground-fault log. Otherwise, the
operate and fault recording are not blocked and the information appears in the normal fault log.
Start and Stop of Fault Recording, Fault Logging, and General Pickup
The
Stabilized pickup
signal initiates fault recording, fault logging, and the general pickup of the func-
tion group. The fault recording starts according to the pre-trigger time before the
Stabilized pickup
signal rises.
With the reset condition of this stage, the fault recording, fault logging, and the general pickup of the function
group are terminated.
Influence on Other Functions to Avoid a Burst of Indications
In this case, the function uses the same mechanism as the Non-directional intermittent ground-fault
protection. For more information, refer to chapter Influence on Other Functions to Avoid a Burst of Signals,
Page 546.
Application and Setting Notes
No Start of the Automatic Reclosing Function
Automatic reclosing is not an effective measure against intermittent ground faults. For this reason, the Direc-
tional intermittent ground-fault protection function is not intended to start the Automatic reclosing func-
tion.
Routing of Pickup Signals
The signal
Pickup
is supposed to be routed to an LED and a relay. The signal
Limited pickup (log)
is
only reported to the fault log and communication interface until the signal
Intermittent gnd.flt.
is
issued. This scheme prevents a burst of indications.
NOTE
To avoid a burst of indications, do not route the signal
Pickup
to the operational log and to the fault log.
Parameter: Threshold
•
Default setting (_:16291:3) Threshold = 1.00 A
With the parameter Threshold, you set the threshold value of the ground current 3I0, measured as RMS
value.
A rather sensitive setting is possible to respond also to short ground faults since the pickup time shortens as
the ground-fault current increases.
Parameter: Directional mode
•
Default setting (_:16291:101) Directional mode = forward
With the parameter Directional mode, you define if the function operates in
forward
or in
reverse
direction.
Parameter: Pickup mode
•
Default setting (_:16291:102) Pickup mode = with 3I0>
6.14.4
Protection and Automation Functions
6.14 Directional Intermittent Ground-Fault Protection
558 SIPROTEC 5, Overcurrent Protection, Manual
C53000-G5040-C017-8, Edition 07.2017
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