ABB RELION REX640 - 4.12.3.7 Signals; HCUBPTOC Input signals

Figure 637: Application example of capacitor bank unbalance protection
The phase current analog input I_A and at least one unbalance current
must be connected to the protection relay for the HCUBPTOC function to
start working.
Steps to measure natural unbalance current
1. The setting Natural Comp Enable must be set to “TRUE”.
2. The capacitor bank must be energized.
3. The capacitor bank compensated unbalance current I_COM_AMPL is observed
from Monitored data.
4. The command
Record unbalance must be activated by selecting the
value “Record” which stores the unbalance reference for future unbalance
calculations.
5. The compensated unbalance current ( I_COM_AMPL) is re-checked to be
approximately zero.
The natural unbalance recording should be made only during the steady-
state condition and when all the capacitor bank elements are assumed to
be in service.
4.12.3.7 Signals
Protection functions
1MRS759142 F
1138 REX640
Technical Manual