Application And Setting Notes - Siemens 7SJ82 Manual

Capacitor Bank Protection
7.4 Current-Unbalance Protection for Capacitors, 3-Phase
Pickup, Tripping Delay
Supervision of the counter contents is phase-segregated. If a counter reaches the preset threshold (parameter
Max. no. of def. elem. phs A , Max. no. of def. elem. phs B , Max. no. of def.
elem. phs C), the stage picks up. When using the parameter Type of counting groups , a selection is
made whether the supervision function occurs group-segregated or with the sum value of both groups. The
pickup starts the time delay. If the time delay has elapsed, the operate indication will be issued.
Automatic Compensation
If the automatic compensation function is enabled, the counter stage is working. If this is not the case, the
readiness status of the stage changes to the state
7.4.5.2

Application and Setting Notes

General Notes
•
The setting notes for the current-threshold value for counting faulty C-elements are provided in chapter
7.4.3.2 Application and Setting Notes
•
In order to react quickly to the simultaneous fault of many C-elements, always use an overcurrent-protec-
tion stage I> with a short tripping delay (< 100 ms) in addition to the counter stage. This is necessary as
the counter function counts each current jump only once, regardless of its height.
Parameter: Type of counting groups
•
Default setting (_:13651:104) Type of counting groups = segregated
When using the parameter Type of counting groups, you specify whether the group-segregated
counter status or the sum of both group counters are compared to the threshold.
Parameter: Maximum Number of Faulty Elements, Operate delay
•
Default setting (_:13651:101) Max. no. of def. elem. phs A = 10
•
Default setting (_:13651:102) Max. no. of def. elem. phs B = 10
•
Default setting (_:13651:103) Max. no. of def. elem. phs C = 10
•
Default setting(_:13651:6) Operate delay = 0.00 s
Set the parameters for the specific application.
It is possible to configure several stages for different tasks:
•
Reporting only (with or without fault record)
Use this stage to report 1 or 2 faulty C-elements. To do this, set the 3 parameters Max. no. of def.
elem. phs A, Max. no. of def. elem. phs B and Max. no. of def. elem. phs C to a
small value (1 or 2). The parameter Operate delay can be set to 0.
If you would like to prevent the operate (tripping) and fault logging (fault log and fault record), set the
parameter Operate & flt.rec. blocked to yes.
If you would like to prevent only the operate (tripping) and the fault logging must occur, remove this
stage from the interface Trip to the circuit breaker (see also
faces with Circuit-Breaker Function Group).
•
Indication with delayed operate
Use this stage to report in case of some faulty C-elements and set a relatively long time delay of the
operate, for example, 2 hours. During this time, the fault of the C-elements can be clarified. If it is
possible to find a solution, the counter status can be reset manually. This way, the stage drops out. If a
solution cannot be found within 2 hours, the stage trips and disconnects the capacitor bank.
•
Immediate operate
The stage is used to initiate the operate immediately after a larger number of C-elements became faulty.
1000
Warning.
as you must set this parameter across all stages.
5.4.2 Structure of the Function Group, Inter-
SIPROTEC 5, Overcurrent Protection, Manual
C53000-G5040-C017-8, Edition 07.2017