GE D90 Plus Instruction Manual page 214

GROUPED PROTECTION ELEMENTS
NOTE:
204
This setting should be at least three times the
the Settings > Protection > Power System > AC Inputs - Current menu. Zone 1 is sealed
in with the current supervision.
Voltage Level
Range: 0.000 to 5.000 pu in steps of 0.001
Default: 0.000 pu
This setting is relevant for applications on series-compensated lines, or in general, if
series capacitors are located between the relaying point and a point for which the zone
shall not overreach. For plain (non-compensated) lines, this setting shall be set to zero.
Otherwise, the setting is entered in per unit of the VT bank configured under the distance
setting. Effectively, this setting facilitates dynamic current-based reach
Source
reduction. In non-directional applications, this setting applies only to the forward reach
of the non-directional zone.
The use of dynamic reach control by selection of a non-zero value for the
setting will disable the subcycle operating time for that particular zone.
Delay
Range: 0.000 to 65.535 seconds in steps of 0.001
Default: 0.000 seconds
This setting enables the user to delay operation of the distance elements and implement
a stepped distance backup protection. The distance element timer applies a short drop
out delay to cope with faults located close to the boundary of the zone when small
oscillations in the voltages and/or currents could inadvertently reset the timer.
Block
Range: any FlexLogic™ operand
Default: Off
This setting enables the user to select a FlexLogic™ operand to block the given ground
distance element. VT fuse fail detection is one of the applications for this setting.
Events
Range: Enabled, Disabled
Default: Disabled
This setting enables and disables the logging of ground distance events in the sequence
of events recorder.
The ground distance operation scheme for zone 1 is shown below.
Figure 179: Ground distance zone 1 operation scheme logic
The ground distance operation scheme for zone 2 is shown below. The logic is analogous
for zones 3 through 5.
Current Cutoff Level
PLUS
D90 LINE DISTANCE PROTECTION SYSTEM – INSTRUCTION MANUAL
CHAPTER 7: PROTECTION
setting specified in
Voltage Level