GE D90 Plus Instruction Manual page 256

GROUPED PROTECTION ELEMENTS
246
The positive-sequence restraint must be considered when testing for pickup accuracy and
response time (multiple of pickup). The operating quantity depends on how test currents
are injected into the relay. For single-phase injection, the operating quantity is
For three-phase pure zero-sequence injection, the operating quantity is
Select the Settings > Protection > Elements > Group 1 > Current > Neutral IOC menu to
open the neutral instantaneous overcurrent configuration window.
Figure 211: Neutral instantaneous overcurrent configuration settings
The following settings are available for each neutral instantaneous overcurrent element.
Function
Range: Enabled, Disabled
Default: Disabled
This setting enables and disables the neutral instantaneous 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 instantaneous overcurrent
protection element.
Pickup
Range: 0.000 to 30.000 pu in steps of 0.001
Default: 1.000 pu
This setting specifies the neutral instantaneous overcurrent pickup level in per-unit
values.
Delay
Range: 0.00 to 600.00 seconds in steps of 0.01
Default: 0.00 seconds
This setting delays the assertion of the
timing coordination with other elements and relays.
Reset Delay
Range: 0.00 to 600.00 seconds in steps of 0.01
Default: 0.00 seconds
This setting specifies a delay for the reset of the neutral instantaneous overcurrent
element between the operate output state and the return to logic 0 after the input
passes outside the defined pickup range. This setting is used to ensure that the relay
output contacts are closed long enough to ensure reception by downstream equipment.
NEUTRAL IOC OP
PLUS
D90 LINE DISTANCE PROTECTION SYSTEM – INSTRUCTION MANUAL
CHAPTER 7: PROTECTION
operands. It is used to achieve
Eq. 23
Eq. 24