Converting Min Ii 67Ig1 To 350 32N - GE Multilin 3 Series Manual

CHAPTER 2: CONVERTING SETTINGS FILES
3 SERIES RETROFIT – INSTRUCTION MANUAL
2.5

Converting MIN II 67IG1 to 350 32N

The 67IG function in MIF II, Option "S", is overcurrent protection specifically designed for
detecting ground faults for isolated ground systems.
Isolated Ground Directional Control in the MIN II relay provides directional protection for
ungrounded systems. In this type of system the neutral is completely isolated from the
ground, as a result of this the ground fault current value is minimum and produced only by
the line capacitive coupling. The relay operation is based on the presence of this capacitive
current plus the detection of an overvoltage condition.
Figure 2-1: MIN II functional block diagram, option S
This same protection can be provided by the 350 relay using the Wattmetric Ground Fault
(32N) element. The Wattmetric ground fault element, also called the Wattmetric Zero-
sequence Directional element, responds to power derived from zero-sequence voltage and
zero-sequence current in a direction specified by the element characteristic angle. The
angle can be set within all four quadrants, so the measured power can be active or
reactive or some combination thereof. Therefore the element can be used to sense either
forward or reverse ground faults in either inductively, capacitively, or resistively grounded
networks.
In order to convert the settings from MIN II 67IG to 350 32N, the settings must be
transferred using the Enervista Setup software, and the Power pickup must be calculated.
CONVERTING MIN II 67IG1 TO 350 32N
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