Signal Sources; Stator Differential; Generator Unbalance - GE G60 Instruction Manual
Generator protection system
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- Instruction manual (780 pages) ,
- Communications manual (532 pages) ,
- Instruction manual (722 pages)
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SETTINGS
CHAPTER 8: APPLICATION OF SETTINGS
8.2.3 Signal sources
Two sources are required for this application example. The "LINE" source uses the phase and auxiliary VT inputs and the CT
input wired to the generator output CT. The "NEUTRL" source uses the phase VT inputs and the CT input wired to the
generator neutral CT. Including the phase VT inputs for both sources allows the user to choose the location of elements
that use both voltage and current. Elements using the auxiliary VT input are assigned to the "NEUTRL" source.
Make the following changes in the EnerVista software or the front panel
and the
SETTINGS SYSTEM SETUP SOURCE 1
menus.
SETTINGS SYSTEM SETUP SOURCE 2
8.2.4 Stator differential
The "LINE" and "NEUTRL" sources are required for the stator differential element. The minimum pickup can usually be set
as low as 0.05 pu (corresponding to 0.25 A secondary or 400 A primary in this example). Set the
setting
STATOR DIFF SLOPE 1
to accommodate for CT errors; a setting of 10% is adequate in most instances. Set the
setting to
STATOR DIFF SLOPE 2
accommodate errors due to CT saturation; a setting of 80% is recommended for most applications. The
STATOR DIFF BREAK
setting must be greater than the maximum load expected for the machine. Set the
setting at the
1
STATOR DIFF BREAK 2
level where CT saturation is expected to occur.
Make the following parameter changes in the EnerVista software or the front panel
SETTINGS GROUPED ELEMENTS
menu.
SETTING GROUP 1 STATOR DIFFERENTIAL
8
8.2.5 Generator unbalance
Stage 1 of the generator unbalance element is typically used to trip the generator. In this example, the I
capability of the
2
2
machine is 8% and the I
T capability is 10. The generator nominal current is:
2
Eq. 8-5
The minimum operate time of stage 1 is to be set to 0.25 seconds, the maximum operating time is to be 10 minutes, and
the reset time is to be set to 4 minutes.
8-4
G60 GENERATOR PROTECTION SYSTEM – INSTRUCTION MANUAL
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