GE UR Series C70 Instruction Manual page 250

5.6 GROUPED ELEMENTS
Up to three identical phase current unbalance elements, one per each CT/VT module configured in hardware, are provided.
The element responds to a differential current signal measured via window-type CTs as a vectorial current difference
between two parallel banks. With the two capacitors in the same phase identical, the said differential current is zero. Small
differences between the capacitors of a given phase result in a small circulating current. Subtracting an adequate portion of
5
the total bank current in a given phase compensates for this inherent unbalance current.
The relay allows manual setting of the inherent unbalance factors, or automatically via the
information, refer to the Theory of Operation and Application of Settings chapters.
The following settings are available for all three elements.
5-126
CUR UNBALCE 1 STG 4
MESSAGE
PKP DELAY:
CUR UNBALCE 1
MESSAGE
DPO DELAY: 0.25 s
CUR UNBL 1 BLK STG1:
MESSAGE
Off
CUR UNBL 1 BLK STG2:
MESSAGE
Off
CUR UNBL 1 BLK STG3:
MESSAGE
Off
CUR UNBL 1 BLK STG4:
MESSAGE
Off
CUR UNBALCE 1
MESSAGE
TARGET: Self-Reset
CUR UNBALCE 1
MESSAGE
EVENTS: Disabled
Grounding method not
relevant, neutral points
must be connected together
Figure 5–56: PHASE CURRENT UNBALANCE BASIC CONNECTIONS
C70 Capacitor Bank Protection and Control System
Range: 0.00 to 600.00 s in steps of 0.01
0.20 s
Range: 0.00 to 600.00 s in steps of 0.01
Range: FlexLogic™ operand
Range: FlexLogic™ operand
Range: FlexLogic™ operand
Range: FlexLogic™ operand
Range: Self-reset, Latched, Disabled
Range: Disabled, Enabled
C70 CAPACITOR BANK RELAY
Phase
CT bank
Window / core-
balance CTs
Phase
CT bank
5 SETTINGS
menu. For more
COMMANDS
BANK
SOURCE
60P
DIF
SOURCE
8347516A1.CDR
GE Multilin