Ground/Sensitive Ground Instantaneous Overcurrent Protection (50G/Sg) - GE 350-A9 Instruction Manual

CHAPTER 6: SETPOINTS
Ground/Sensitive Ground instantaneous overcurrent protection
(50G/SG)
350 FEEDER PROTECTION SYSTEM – INSTRUCTION MANUAL
The relay has one Ground/Sensitive Ground Instantaneous Overcurrent protection element
per setpoint group. The settings of these functions are applied to the gound/sensitive
ground current for pickup and trip flags. The Ground IOC pickup flag is asserted, when the
ground current is above the PKP value. The Ground IOC operate flag is asserted if the
element stays picked up for the time defined by the Ground IOC PKP Delay setting. If the
pickup time delay is set to 0.00 seconds, the pickup and operate flags will be asserted at
the same time. The element drops from pickup without operation, if the ground current
drops below 97-99% of the pickup value.
The following path is available using the keypad. For instructions on how to use the
keypad, please refer to Chapter 3 - Working with the Keypad.
PATH: SETPOINTS > S3 PROTECTION > SETPOINT GROUP 1(2) > GROUND IOC1(2)
GND IOC FUNCTION
Range: Disabled, Trip, Alarm, Latched Alarm
Default: Disabled
For details see Common
GND IOC PKP
Range: Disabled, 0.05 to 20.00 x CT in steps of 0.01 x CT
Default: 1.00 x CT
SENS.GND IOC PKP
Range: 0.005 to 3.00 x CT in steps of 0.001 x CT
Default: 1.00 x CT
This setting sets the ground overcurrent pickup level specified per times CT. For example,
a PKP setting of 0.9 x CT with 300:5 CT translates into 270A primary current.
GND IOC DELAY
Range: 0.00 to 300.00 sec in steps of 0.01 sec
Default: 0.00 sec
This setting provides selection for pickup time delay used to delay the operation of the
protection.
GND IOC DIRECTION
Range: Disabled, Forward, Reverse
Default: Disabled
This setting provides control to the Ground IOC1(2) function in terms of permitting
operation upon fault conditions in the selected current flow direction, and blocking it,
when faults occur in the opposite direction.
A special case is considered when fault direction is undefined. Then "BLK OC DIR UN"
setting in Ground Directional defines the fault direction.
OUTPUT RELAY X
For details see Common
BLOCK 1/2/3
For details see Common
setpoints.
setpoints.
setpoints.
S3 PROTECTION
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