GE D90 Plus Instruction Manual page 271

CHAPTER 7: PROTECTION
Neutral overvoltage
PLUS
D90 LINE DISTANCE PROTECTION SYSTEM – INSTRUCTION MANUAL
Pickup
Range: 0.000 to 1.100 pu in steps of 0.001
Default: 1.000 pu
This setting specifies the phase overvoltage pickup level in per-unit values.
Delay
Range: 0.00 to 600.00 seconds in steps of 0.01
Default: 1.00 seconds
This setting specifies the minimum operating time of the phase overvoltage element.
Reset Delay
Range: 0.00 to 600.00 seconds in steps of 0.01
Default: 1.00 seconds
This setting specifies the minimum reset time of the phase overvoltage element.
Block
Range: any FlexLogic™ operand or shared operand
Default: Off
Assertion of the operand assigned to this setting blocks the phase overvoltage element.
Events
Range: Enabled, Disabled
Default: Disabled
This setting enables and disables the logging of phase overvoltage events in the
sequence of events recorder.
The logic for the phase overvoltage element is shown below. The logic is identical for all
phase overvoltage elements.
Figure 228: Phase overvoltage scheme logic
There are three neutral overvoltage elements available. The neutral overvoltage element
can be used to detect asymmetrical system voltage condition due to a ground fault or to
the loss of one or two phases of the source. The element responds to the system neutral
voltage (3V_0), calculated from the phase voltages. The nominal secondary voltage of the
phase voltage channels entered in the
used when setting the pickup level.
GROUPED PROTECTION ELEMENTS
setting is the per-unit base
Phase VT Secondary
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