Compensation Method 2 - GE L90 Instruction Manual

CHAPTER 8: APPLICATION OF SETTINGS
contact with the
BLOCK GPS TIME REF
2. Create FlexLogic similar to that shown as follows to block the 87L element on GPS loss if step change in the channel
delay occurs during GPS loss conditions or on a startup before the GPS signal is valid. For three-terminal systems, the
operand must be ORed with the
87L DIFF 1 TIME CHNG
output is reset if the GPS signal is restored and the 87L element is ready to operate.
3. Assign virtual output BLOCK 87L (VO1) to the 87L Current Differential Block setting (
SETTING GROUP  LINE DIFFERENTIAL...  CURRENT DIFFERENTIAL  CURRENT DIFF BLOCK
backup protection, raise an alarm, and perform other functions as per the given protection philosophy.

8.3.3 Compensation method 2

Enable GPS compensation on the loss of the GPS signal at any terminal and block the 87L element after a specified time.
This is a simple and conservative way of using the GPS feature. Follow steps 1 and 3 in compensation method 1. The
FlexLogic is simple: 87L DIFF GPS FAIL-Timer-Virtual Output Block 87L (VO1). It is recommended that the timer be set no
higher than 10 seconds.
L90 LINE CURRENT DIFFERENTIAL SYSTEM – INSTRUCTION MANUAL
setting.
87L DIFF 2 TIME CHNG
CHANNEL ASYMMETRY COMPENSATION USING GPS
FlexLogic operand. The Block 87L (VO1)
SETTINGS  GROUPED ELEMENTS 
). It can be used to enable
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