ABB RELION REX640 Technical Manual page 1138

Protection functions
Figure 637: Application example of capacitor bank unbalance protection
Steps to measure natural unbalance current
1.
2.
3.
4.
5.
4.12.3.7 Signals
1138
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.
Natural Comp Enable must be set to "TRUE".
The setting
The capacitor bank must be energized.
The capacitor bank compensated unbalance current I_COM_AMPL is observed
from Monitored data.
Record unbalance must be activated by selecting the
The command
value "Record" which stores the unbalance reference for future unbalance
calculations.
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.
1MRS759142 F
REX640
Technical Manual