GE D90 Plus Instruction Manual page 263

CHAPTER 7: PROTECTION
Ground time overcurrent
NOTE:
PLUS
D90 LINE DISTANCE PROTECTION SYSTEM – INSTRUCTION MANUAL
Figure 215: Neutral directional overcurrent 1 scheme logic
This element can provide a required time-delay operating characteristic versus the applied
current or be used as a simple definite time element. The ground current input value is the
quantity measured by the ground input CT and is the fundamental phasor or RMS
magnitude. Two methods of resetting operation are available: "Timed" and
"Instantaneous." When the element is blocked, the time accumulator resets according to
the reset characteristic. For example, if the element reset characteristic is set to
"Instantaneous" and the element is blocked, the time accumulator clears immediately.
These elements measure the current that is connected to the ground channel of an AC
module. This channel can 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 TOC menu to
open the ground time overcurrent configuration window.
GROUPED PROTECTION ELEMENTS
253