Application And Setting Notes - Siemens 7SJ82 Manual

Capacitor Bank Protection
7.5 Current-Unbalance Protection for Capacitors, 1-Phase
Definition of the Group and Fault Location in Case of a Capacitor Dual Switching
If the capacitor is designed with dual switching function, the following definition is assumed:
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Figure 7-24
The black dot indicates the orientation of the current transformer. For the connection of the current trans-
former shown in the previous figure, the following definition applies:
•
Group 1: C1
•
Group 2: C2
In order to determine the fault location (group 1 or 2) correctly, use the parameter Capacitor element
type (in FB General of the Capacitor bank function group) to tell the device whether the elements of the
capacitor bank have internal fuses or not.
The angle reference of the unbalanced-current phasor to the reference current I
direction of the unbalanced current and, thus, the affected group is determined. If the direction cannot be
determined with confidence, an appropriate indication will be generated.
7.5.3.2

Application and Setting Notes

Parameter: MP selection
•
Default setting (_:13501:81) MP selection = None
With the MP selection parameter, you can select from a list the measuring point that is connected to the
I Unbalanced interface of the Capacitor bank function group.
The setting applies equally to all stages of the function.
In the default setting, a measuring point is not selected. You must select a measuring point. If you do not
select a measuring point, an inconsistency is indicated via the read-only parameter Consistency failure.
Parameter: Automatic compensation
•
Default setting (_:2311:101) Automatic compensation = no
The parameter applies equally to all stages of the function that work with compensated measurands.
If no counter stages are applied, Siemens recommends to switch the automatic compensation off and use the
manual compensation. You can find more information on this recommendation in chapter
and Setting Notes
If the counter stages are applied, the automatic compensation must be switched on, otherwise the counting
function will not work.
Parameter: De-energ.time w/o comp.
•
Default setting (_:2311:104) De-energ.time w/o comp. = 2.00 s
In case of networks faults, the faulty phases are discharged. With the returning voltage after fault clearance,
charging takes place. For such conditions, Siemens recommends that no automatic full compensation takes
1008
Definition of the Fault-Location Information
(setting notes for the operate delay of the I> stage).
is used to determine the
c
7.5.4.2 Application
SIPROTEC 5, Overcurrent Protection, Manual
C53000-G5040-C017-8, Edition 07.2017