GE G30 Instruction Manual page 595

CHAPTER 8: APPLICATION OF SETTINGS
The selection of all standard curves (and FlexCurves) is allowed for easy coordination with system relaying. For the
example system, an IEEE extremely inverse curve is used and a setting is chosen such that the operate time for a three-
phase fault on the high side of the transformer is 0.75 seconds. For simplicity, the power system contribution is not
considered.
The equation for an IEEE extremely inverse curve is as follows:
where A = 28.2, B = 0.1217, and p = 2. Solving for TDM, we have:
Since this element coordinates with system protections, a timed reset is chosen. The element must be blocked for a VT fuse
failure. The neutral source is chosen. Make the following changes in the EnerVista software or the front panel
GROUPED ELEMENTS  SETTING GROUP 1  PHASE CURRENT  PHASE TOC1
G30 GENERATOR PROTECTION SYSTEM – INSTRUCTION MANUAL
menu.
SETTINGS
Eq. 8-18
Eq. 8-19
Eq. 8-20
Eq. 8-21
Eq. 8-22
Eq. 8-23
Eq. 8-24
SETTINGS 
8
8-11