•
Measurement of the RMS value:
This method of measurement determines the current amplitude from the sampled values according to
the defining equation of the RMS value. Harmonics are included in the analysis.
Blocking the Stage via Binary Input Signal
You can block the stage externally or internally via the binary input signal
>Block stage
. In the event of
blocking, the picked up stage will be reset.
Blocking the Time Delay
You can use the binary input signal
>Block delay & op.
to prevent the start of the time delay and thus
also the operate indication. A running time delay is reset. The pickup is indicated and a fault record is opened.
Blocking the Tripping via the Device-Internal Inrush-Current Detection Function
The Blk. w. inrush curr. detect. parameter allows you to define whether the operate indication of
the stage should be blocked by exceeding of the threshold values due to an inrush current. In case of a
blocking, the stage picks up. The start of the time delay and the operate indication are blocked. The function
indicates this through a corresponding indication. If the blocking drops out and the threshold value of the
stage is still exceeded, the time delay is started.
Application and Setting Notes
Parameter: Blk. w. inrush curr. detect.
•
Default setting (_:27) Blk. w. inrush curr. detect. = no
With the Blk. w. inrush curr. detect. parameter, you determine whether the tripping is blocked
during the detection of an inrush current.
Parameter: Method of measurement
•
Recommended setting value (_:8) Method of measurement = fundamental comp.
With the Method of measurement parameter, you define whether the stage uses the fundamental
comp. (standard method) or the calculated RMS value.
Parameter Value
Description
fundamental comp.
Select this method of measurement if harmonics or transient current peaks
are to be suppressed.
Siemens recommends using this method as the standard method.
RMS value
Select this method of measurement if you want the stage to take harmonics
into account (for example, at capacitor banks). Consider that aperiodic DC
components present in the secondary circuit are measured and can cause
an overfunction.
For this method of measurement, do not set the threshold value of the
stage to less than 0.1 I
rated,sec
. If currents from more than one measuring
point are added up in the current interface of a function group, the setting
value should not be set lower than 0.1 I
rated,sec
multiplied by the number of
added currents.
Parameter: Threshold
•
Default setting (_:3) Threshold = 0.050 A
The Threshold parameter allows you to set the threshold value of the ground current 3I0.
Parameter: Pickup delay
•
Default setting (_:102) Pickup delay = 0.00 s
6.15.11.2
Protection and Automation Functions
6.15 Sensitive Ground-Fault Detection
614 SIPROTEC 5, Overcurrent Protection, Manual
C53000-G5040-C017-8, Edition 07.2017
To Next Page
Loading...
