Stator Ground Fault - GE G60 Instruction Manual

CHAPTER 8: APPLICATION OF SETTINGS
Set the zone 3 reach at 120% of the generator transient reactance. Compare the time delay of this element to the
generator decrement curve to verify the adequacy of this setting.
An mho shape has been chosen for this example. Therefore, the quadrilateral settings are left at their default values. Make
the following changes in the EnerVista software or the front panel
 DISTANCE  PHASE DISTANCE Z1(3)

8.2.10 Stator ground fault

8.2.10.1 Auxiliary overvoltage
Stator ground fault protection is implemented with an overvoltage element connected at the generator neutral resistor.
The auxiliary overvoltage element is used in this example. The auxiliary voltage input has been assigned previously to the
NEUTRL source. In this example, the element is set to protect 97% of the stator against ground faults.
Set the time delay longer than the longest normal clearing time for faults outside the generator zone. If the phase VTs are
wye-connected, then also coordinate this element with VT secondary fuses to prevent false operations for VT secondary
ground faults. For the sample system, a time delay of 1 second is to be used. Make the following changes in the EnerVista
software or the front panel
SETTINGS  GROUPED ELEMENTS  SETTING GROUP 1  VOLTAGE ELEMENTS  AUXILIARY OV1
menu.
G60 GENERATOR PROTECTION SYSTEM – INSTRUCTION MANUAL
SETTINGS  GROUPED ELEMENTS  SETTING GROUP 1
menus.
SETTINGS
Eq. 8-28
Eq. 8-29
8
Eq. 8-30
8-9