Activation/Blocking Counting
If at least one counter stage is enabled, the counting function is active. Furthermore, the counting function
works only if the automatic compensation is enabled.
In order to prevent counting as a consequence of the charging process, the counter function is implicitly
blocked for 250 ms by setting
I
unbal.,comp.
to 0 A, after the capacitor energizing has been detected.
Measurands, Counting
The measurand is the 1-phase compensated unbalanced current I
unbal.,comp.
. If a single C-element is faulty, an
unbalance occurs between the neutral points of the 2 capacitor banks. This unbalance causes an unbalanced
current; this means, a small current jump occurs in the unbalanced current. Set the parameter Thresh.
defective C-elem., so that this current jump can be detected (see also 7.5.3.2 Application and Setting
Notes). The unbalanced current that was caused by the fault must exceed the threshold for 100 ms before the
affected phase and the affected group are determined and counting (incrementing the counter) takes place.
The angle reference of the unbalanced-current phasor to the reference current I
c,A
is used to determine the
phase of the faulty C element. Thus, phase-segregated counting is possible. There is one counter for each
phase and group. After the counting, the existing unbalance is compensated; this means, the unbalance is
reset to 0 A. If the faulty group cannot be determined, the unbalance is also compensated.
Resetting/Setting the Counters
You can reset or set the counters of group 1 and group 2 via:
•
On-site operation panel directly on the device
•
Online DIGSI connection to the device
•
Binary input
>Reset all counters
(only reset of all counters)
•
Communication connection with the control center
You can directly set or reset the counters via IEC 61850 by setting the counter values to the desired value. If
you want to reset the counters via DNP3, IEC 60870-5-103, Modbus, or IEC 60870-5-104, an additional config-
uration with CFC is necessary. For more information, refer to chapter 7.5.3.2 Application and Setting Notes.
Functional Measured Values
Values
Description Primary Secondary % Referenced to
(_:2311:300) Iunbl.cp Compensated unbalanced
current I
unbal.,comp.
kA A Parameter Rated primary
current
(_:2311:301) Iunbl. Non-compensated unbal-
anced current I
unbal.
kA A Parameter Rated primary
current
(_:2311:323) Cp.vect. Compensation vector I
comp.,vect.
kA A Parameter Rated primary
current
You can find the value of the parameter Rated primary current of the preceding table in the chapter
6.1.8 Settings according to the specified parameter MP selection.
I
comp.,vect.
is normalized with I
c
. The normalization is carried out no matter if the parameter Normalization
with Ic is set to yes or no. I
comp.,vect.
keeps its value unchanged until the next compensation occurs.
[fo_compensation vector, 1, en_US]
Where:
I
unbal.op.
Operational unbalanced current at the moment the compensation is carried out
I
c,rated
Rated current of the capacitor bank
I
c
Current of the capacitor bank at the moment the compensation is carried out
Capacitor Bank Protection
7.5 Current-Unbalance Protection for Capacitors, 1-Phase
SIPROTEC 5, Overcurrent Protection, Manual 1007
C53000-G5040-C017-8, Edition 07.2017
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