Generator Unbalance (Ansi 46) - GE G60 Instruction Manual

GROUPED ELEMENTS

5.7.10 Generator unbalance (ANSI 46)

SETTINGS  GROUPED ELEMENTS  SETTING GROUP 1(6)  GENERATOR UNBALANCE
 GENERATOR
 UNBALANCE
5
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
GEN UNBAL STG1 PICKUP
specified by the
GEN UNBAL INOM
the machine.
GEN UNBAL STG1 K-VALUE
manufacturer (see ANSI C50.13 for details).
GEN UNBAL STG1 TMIN
expires. This is set to prevent false trips for faults that would be cleared normally by system protections.
GEN UNBAL STG1 TMAX
maximum tripping time for low level unbalances.
5-246
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
— Defines the pickup of the stage 1 element expressed as a percentage of the nominal current as
setting. It is set typically at the maximum continuous negative sequence current rating of
— The negative sequence capability constant. This value is normally provided by the generator
— The minimum operate time of the stage 1 element. The stage does not operate before this time
— The maximum operate time of the stage 1 element. This setting can be applied to limit the
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
,
Range: Enabled Disabled
G60 GENERATOR PROTECTION SYSTEM – INSTRUCTION MANUAL
CHAPTER 5: SETTINGS
,
Disabled
Eq. 5-26