The outputs of the function are the ALARM START, ALARM, START, TRIP, and BLOCKED signals. The
capacitor bank current unbalance function uses a total of eight (8) separate setting groups which can
be selected from one common source.
The function can operate on instant or time-delayed mode. The function includes CT saturation
checking which allows the function to start and operate accurately during CT saturation.
The operational logic consists of the following:
• input magnitude selection
• input magnitude processing
• saturation check
• threshold comparator
• block signal check
• time delay characteristics
• output processing.
The inputs for the function are the following:
• operating mode selections
• setting parameters
• digital inputs and logic signals
• measured and pre-processed current magnitudes.
The function outputs the ALARM START, ALARM, START, TRIP and BLOCKED signals which can be
used for direct I/O controlling and user logic programming. The function generates general time-
stamped ON/OFF events to the common event buffer from each of the five (5) output signals. In the
instant operating mode the function outputs START and TRIP events simultaneously with an equivalent
time stamp. The time stamp resolution is 1 ms. The function also provides a resettable cumulative
counter for the ALARM START, ALARM, START, TRIP and BLOCKED events.
Measured input
The function block uses analog current measurement values. The monitored magnitude is equal
to RMS values. A -20 ms averaged value of the selected magnitude is used for pre-fault data
registering.
Table. 5.3.2.2 - 54. Measurement inputs of the Iuc> function.
Signal
Description
Time base
IL1RMS
RMS measurement of phase L1 (A) current
5ms
IL2RMS
RMS measurement of phase L2 (B) current
5ms
IL3RMS
RMS measurement of phase L3 (C) current
5ms
A
AQ
Q-C213
-C213
Instruction manual
Version: 2.04
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