CHAPTER 7: PROTECTION
GROUPED PROTECTION ELEMENTS
D90
PLUS
LINE DISTANCE PROTECTION SYSTEM – INSTRUCTION MANUAL
241
Select the
Settings > Protection > Elements > Group 1 > Current > Neutral TOC
menu
item to open the neutral time overcurrent configuration window.
Figure 205: Neutral time overcurrent configuration settings
The following settings are available for each neutral time overcurrent element.
Function
Range: Enabled, Disabled
Default: Disabled
This setting enables and disables the neutral time overcurrent protection element.
Source
Range: LINE (SRC 1), BKR 1 (SRC 2), BKR 2 (SRC 3)
Default: LINE (SRC 1)
This setting selects the signal source for the neutral time overcurrent protection
element.
Input
Range: Phasor, RMS
Default: Phasor
This setting selects how neutral current input quantities are interpreted by the D90
Plus
.
Inputs can be selected as fundamental phasor magnitudes or total waveform RMS
magnitudes as required by the application.
Pickup
Range: 0.000 to 30.000 pu in steps of 0.001
Default: 1.000 pu
This setting specifies the neutral time overcurrent pickup level in per-unit values.
Curve
Range: IEEE Mod Inv, IEEE Very Inv, IEEE Ext Inv, IEC Curve A, IEC Curve B, IEC Curve C, IEC
Short Inv, IAC Ext Inv, IAC Very Inv, IAC Inverse, IAC Short Inv, I2t, Definite Time, FlexCurve A,
FlexCurve B, FlexCurve C, FlexCurve D
Default: IEEE Mod Inv
This setting selects the inverse time overcurrent curve style.
TD Multiplier
Range: 0.00 to 600.00 in steps of 0.01
Default: 1.00
This setting specifies a multiple of the base curve shape specified by the
Curve
setting.
Programming this value to zero results in an instantaneous response to all current levels
above pickup.