252
D90
PLUS
LINE DISTANCE PROTECTION SYSTEM – INSTRUCTION MANUAL
GROUPED PROTECTION ELEMENTS
CHAPTER 7: PROTECTION
Reset
Range: Instantaneous, Timed
Default: Instantaneous
The “Instantaneous” reset method is intended for applications with other relays, such as
most static relays, which set the energy capacity directly to zero when the current falls
below the reset threshold. The “Timed” reset method can be used where the relay must
coordinate with electromechanical relays.
Block
Range: any FlexLogic™ operand or shared operand
Default: Off
Assertion of the operand assigned to this setting blocks operation of the ground time
overcurrent element.
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 time overcurrent events in the
sequence of events recorder.
The logic for the ground time overcurrent 1 element is shown below. The logic is identical
for all ground time overcurrent elements.
Figure 213: Ground time overcurrent scheme logic
Ground instantaneous overcurrent
The ground instantaneous overcurrent element may be used as an instantaneous element
with no intentional delay or as a definite time element. The ground current input is the
quantity measured by the ground input CT and is the fundamental phasor magnitude.
NOTE
NOTE:
These elements measure the current that is connected to the ground channel of an AC
module. This channel may be equipped with a standard or sensitive input. The conversion
range of a standard channel is from 0.02 to 46 times the CT rating. The conversion range of
a sensitive channel is from 0.002 to 4.6 times the CT rating.
Select the
Settings > Protection > Elements > Group 1 > Current > Ground IOC
menu
item to open the ground instantaneous overcurrent configuration window.
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