With the 3I0 harm. dropout ratio parameter, you define the dropout threshold for the Min. 3I0>
harmonic parameter.
Lowering this dropout threshold enlarges the range and the period of direction determination under fluctu-
ating zero-sequence harmonics. Siemens recommends using the default setting.
Parameter: Directional mode
•
Default setting (_:106) Directional mode = forward
With the Directional mode parameter, you define for which direction result the function generates the
pickup state:
•
If the Directional mode parameter is set as forward or reverse, the stage picks up when the direc-
tion result equals the parameterized direction, and the
Pickup
is signaled with the determined direction.
•
If the Directional mode parameter is set as non-directional, the stage picks up regardless of the
direction result, and the
Pickup
is signaled with the unknown information.
Parameter: Operate delay
•
Default setting (_:6) Operate delay = 1.00 s
The Operate delay parameter determines the time during which the pickup conditions must be met to
issue the operate indication. The operate indication is issued when this time expires.
NOTE
When both the Operate delay and the Dir.-result extension are applied, the Operate delay
should usually be set to a considerably greater value than the Dir.-result extension. If the Operate
delay is less than the Dir.-result extension, the function will operate for each fault regardless of
the fault duration, as long as the fault direction equals the set direction.
Parameter: Operate & flt.rec. blocked
•
Default setting (_:2) Operate & flt.rec. blocked = no
With the Operate & flt.rec. blocked parameter, you block the operate indication, the fault recording,
and the fault log. In this case, a ground-fault log is created instead of the fault log.
Parameter: Blk. by meas.-volt. failure
•
Default setting (_:10) Blk. by meas.-volt. failure = yes
You use the Blk. by meas.-volt. failure parameter to control the behavior of the stage when a
measuring-voltage failure is detected.
A measuring-voltage failure can only be detected if one of the following 2 conditions is met:
•
The device-internal supervision function Measuring-voltage failure detection is configured and
enabled.
•
The binary input signal
>Open
of the function block Voltage-transformer circuit breaker is connected to
the voltage-transformer circuit breaker.
Parameter Value
Description
yes
The protection stage is blocked (= default setting). Siemens recommends
using the default setting.
no
The protection stage is not blocked.
Protection and Automation Functions
6.15 Sensitive Ground-Fault Detection
606 SIPROTEC 5, Overcurrent Protection, Manual
C53000-G5040-C017-8, Edition 07.2017
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