254
D90
PLUS
LINE DISTANCE PROTECTION SYSTEM – INSTRUCTION MANUAL
GROUPED PROTECTION ELEMENTS
CHAPTER 7: PROTECTION
Events
Range: Enabled, Disabled
Default: varies with UR
Plus
-series model; refer to the EnerVista UR
Plus
Setup software
This setting enables and disables the logging of ground instantaneous overcurrent
events in the sequence of events recorder.
The logic for the ground instantaneous overcurrent 1 element is shown below. The logic is
identical for all ground instantaneous overcurrent elements.
Figure 215: Ground instantaneous overcurrent scheme logic
Negative-sequence time overcurrent
The negative-sequence time overcurrent element may be used to determine and clear
unbalance in the system. The input for calculating negative-sequence current is the
fundamental phasor value.
Two methods of resetting operation are available: timed and instantaneous. When the
element is blocked, the time accumulator will reset according to the reset characteristic.
For example, if the element reset characteristic is set to instantaneous and the element is
blocked, the time accumulator will be cleared immediately.
Select the
Settings > Protection > Elements > Group 1 > Current > Negative Sequence
TOC
menu item to open the negative-sequence time overcurrent configuration window.
Figure 216: Negative-sequence time overcurrent configuration settings
The following settings are available for each negative-sequence time overcurrent element.
Function
Range: Enabled, Disabled
Default: Disabled
This setting enables and disables the negative-sequence time overcurrent protection
element.
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