GE C70 Instruction Manual page 279

5 SETTINGS
MESSAGE
MESSAGE
MESSAGE
MESSAGE
MESSAGE
MESSAGE
MESSAGE
MESSAGE
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
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.
Figure 5–63: PHASE CURRENT UNBALANCE BASIC CONNECTIONS
The following settings are available for all three elements.
GE Multilin
CUR UNBALCE 1 STG 4
PKP DELAY: 0.20 s
CUR UNBALCE 1
DPO DELAY: 0.25 s
CUR UNBL 1 BLK STG1:
Off
CUR UNBL 1 BLK STG2:
Off
CUR UNBL 1 BLK STG3:
Off
CUR UNBL 1 BLK STG4:
Off
CUR UNBALCE 1
TARGET: Self-Reset
CUR UNBALCE 1
EVENTS: Disabled
Window / core-
balance CTs
Grounding method not
relevant, neutral points
must be connected together
C70 Capacitor Bank Protection and Control System
5.6 GROUPED ELEMENTS
Range: 0.00 to 600.00 s in steps of 0.01
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
COMMANDS
C70 CAPACITOR BANK RELAY
Phase
BANK
CT bank
SOURCE
60P
Phase
DIF
SOURCE
CT bank
8347516A1.CDR
5
menu. For more
5-155