GE Multilin G60 Generator Protection System 5-207
5 SETTINGS 5.6 GROUPED ELEMENTS
5
5.6.10 GENERATOR UNBALANCE
PATH: SETTINGS GROUPED ELEMENTS SETTING GROUP 1(6) 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 which 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
nom
is the generator rated current and K is the negative-sequence capability constant nor-
mally provided by the generator manufacturer.
• GEN UNBAL INOM: This setting is the rated full load current of the machine.
• GEN UNBAL STG1 PICKUP: This setting defines the pickup of the stage 1 element expressed as a percentage of the
nominal current as specified by
GEN UNBAL INOM setting. It is typically set at the maximum continuous negative
sequence current rating of the machine.
• GEN UNBAL STG1 K-VALUE: This setting is the negative sequence capability constant. This value is normally pro-
vided by the generator manufacturer (refer to ANSI C50.13 for details).
• GEN UNBAL STG1 TMIN: This is the minimum operate time of the stage 1 element. The stage will not operate before
this time expires. This is set to prevent false trips for faults that would be cleared normally by system protections.
• GEN UNBAL STG1 TMAX: This is the maximum operate time of the stage 1 element. This setting can be applied to
limit the maximum tripping time for low level unbalances.
GENERATOR
UNBALANCE
GENERATOR UNBAL
FUNCTION: Disabled
Range: Disabled, Enabled
MESSAGE
GEN UNBAL SOURCE:
SRC 1
Range: SRC 1, SRC 2, SRC 3, SRC 4
MESSAGE
GEN UNBAL INOM:
0.800 pu
Range: 0.000 to 1.250 pu in steps of 0.001
MESSAGE
GEN UNBAL STG1
PICKUP: 8.00%
Range: 0.00 to 100.00% in steps of 0.01
MESSAGE
GEN UNBAL STG1
K-VALUE: 1.00
Range: 0.00 to 100.00 in steps of 0.01
MESSAGE
GEN UNBAL STG1 TMIN:
0.250 s
Range: 0.000 to 50.000 s in steps of 0.001
MESSAGE
GEN UNBAL STG1 TMAX:
600.00 s
Range: 0.0 to 1000.0 s in steps of 0.1
MESSAGE
GEN UNBAL STG1
K-RESET: 240.00 s
Range: 0.0 to 1000.0 s in steps of 0.1
MESSAGE
GEN UNBAL STG2
PICKUP: 3.0%
Range: 0.00 to 100.00% in steps of 0.01
MESSAGE
GEN UNBAL STG2 PKP
DELAY: 5.0 s
Range: 0.0 to 1000.0 s in steps of 0.1
MESSAGE
GEN UNBAL BLK:
Off
Range: FlexLogic operand
MESSAGE
GEN UNBAL TARGET:
Self-Reset
Range: Self-reset, Latched, Disabled
MESSAGE
GEN UNBAL EVENTS:
Disabled
Range: Enabled, Disabled
T
K
I
2
I
nom
⁄()
2
---------------------------
=