GE C70 Instruction Manual page 308

5.6 GROUPED ELEMENTS
Up to three identical voltage differential elements, one per each VT bank configured in hardware, are provided.
5
The element responds to a differential signal between magnitudes of the bus and tap voltages. The latter is scaled using a
matching factor to account for the position of the tap. An automatic setting procedure is available under the
menu to calculate automatically the matching factor when installing the relay or after repairs of the bank.
The function works with grounded and ungrounded banks. In the latter case, the neutral point voltage must be measured by
the relay. For additional information, refer to the Theory of Operation and Application of Settings chapters.
The following settings are available for each voltage differential element.
5-184
VOLTAGE DIF 1 STG 3
MESSAGE
PKP DELAY:
VOLTAGE DIF 1 STG 4
MESSAGE
PKP DELAY:
VOLTAGE DIF 1
MESSAGE
DPO DELAY: 0.25 s
VOLT DIF 1 BLK STG1:
MESSAGE
Off
VOLT DIF 1 BLK STG 2:
MESSAGE
Off
VOLT DIF 1 BLK STG 3:
MESSAGE
Off
VOLT DIF 1 BLK STG 4:
MESSAGE
Off
VOLT DIF 1 TARGET:
MESSAGE
Self-Reset
VOLT DIF 1 EVENTS:
MESSAGE
Disabled
Figure 5–81: VOLTAGE DIFFERENTIAL BASIC CONNECTIONS
C70 Capacitor Bank Protection and Control System
Range: 0.00 to 600.00 s in steps of 0.01
1.00 s
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
VT bank
Phase
VT bank
Aux VT
For ungrounded
banks only
5 SETTINGS
COMMAND
BUS
SOURCE
87V
TAP
SOURCE
834738A1.CDR
GE Multilin