GE D90 Plus Instruction Manual page 280

GROUPED PROTECTION ELEMENTS
Neutral overvoltage
270
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.
The neutral overvoltage element can provide a time-delayed operating characteristic
versus the applied voltage (initialized from FlexCurves A, B, or C) or be used as a definite
time element. The source assigned to this element must be configured for a phase VT.
VT errors and normal voltage unbalance must be considered when setting this element.
This function requires the VTs to be wye-connected.
Select the Settings > Protection > Elements > Group 1 > Voltage > Neutral OV menu to
open the neutral overvoltage configuration window.
Figure 232: Neutral overvoltage configuration settings
The following settings are available for each neutral overvoltage element.
Function
Range: Enabled, Disabled
Default: Disabled
This setting enables and disables the neutral overvoltage protection element.
Figure 231: Phase overvoltage logic
Phase VT Secondary
PLUS
D90 LINE DISTANCE PROTECTION SYSTEM – INSTRUCTION MANUAL
CHAPTER 7: PROTECTION
setting is the per-unit base