Generator Unbalance (Ansi 46) - GE G30 Instruction Manual

CHAPTER 5: SETTINGS

5.7.8 Generator unbalance (ANSI 46)

SETTINGS  GROUPED ELEMENTS  SETTING GROUP 1(6)  GENERATOR UNBALANCE
 GENERATOR
 UNBALANCE
The generator unbalance element protects the machine from rotor damage due to excessive negative-sequence current.
The element has an inverse time stage that is typically used for tripping and a definite time stage typically used for alarm
purposes. The inverse time stage operating characteristic is defined by the following equation:
where
I is the generator rated current
nom
K is the negative-sequence capability constant normally provided by the generator manufacturer
— This setting is the rated full load current of the machine.
GEN UNBAL INOM
— Defines the pickup of the stage 1 element expressed as a percentage of the nominal current as
GEN UNBAL STG1 PICKUP
specified by the
GEN UNBAL INOM
the machine.
— The negative sequence capability constant. This value is normally provided by the generator
GEN UNBAL STG1 K-VALUE
manufacturer (see ANSI C50.13 for details).
— The minimum operate time of the stage 1 element. The stage does not operate before this time
GEN UNBAL STG1 TMIN
expires. This is set to prevent false trips for faults that would be cleared normally by system protections.
— The maximum operate time of the stage 1 element. This setting can be applied to limit the
GEN UNBAL STG1 TMAX
maximum tripping time for low level unbalances.
G30 GENERATOR PROTECTION SYSTEM – INSTRUCTION MANUAL
GENERATOR UNBAL

FUNCTION: Disabled
GEN UNBAL SOURCE:

SRC 1
GEN UNBAL INOM:

0.800 pu
GEN UNBAL STG1

PICKUP: 8.00%
GEN UNBAL STG1

K-VALUE: 1.00
GEN UNBAL STG1 TMIN:

0.250 s
GEN UNBAL STG1 TMAX:

600.00 s
GEN UNBAL STG1

K-RESET: 240.00 s
GEN UNBAL STG2

PICKUP: 3.0%
GEN UNBAL STG2 PKP

DELAY: 5.0 s
GEN UNBAL BLK:

Off
GEN UNBAL TARGET:

Self-Reset
GEN UNBAL EVENTS:

Disabled
setting. It is set typically at the maximum continuous negative sequence current rating of
GROUPED ELEMENTS
Range: Disabled, Enabled
Range: SRC 1, SRC 2, SRC 3, SRC 4
Range: 0.000 to 1.250 pu in steps of 0.001
Range: 0.00 to 100.00% in steps of 0.01
Range: 0.00 to 100.00 in steps of 0.01
Range: 0.000 to 50.000 s in steps of 0.001
Range: 0.0 to 1000.0 s in steps of 0.1
Range: 0.0 to 1000.0 s in steps of 0.1
Range: 0.00 to 100.00% in steps of 0.01
Range: 0.0 to 1000.0 s in steps of 0.1
Range: FlexLogic operand
,
Range: Self-reset, Latched Disabled
,
Range: Enabled Disabled
5
Eq. 5-48
5-217