GE Multilin G650 Manual page 204

5 SETTINGS
5.4.8.3 GENERATOR UNBALANCE (46)
The generator unbalance element protects the machine from rotor damage due to excessive negative sequence current.
Negative sequence current is used as operation element. The element has an inverse time stage (stage 1), typically used
for tripping, and a definite time stage (stage 2) typically used for alarm purposes.
Stage 1 trip time is based on an inverse time curve, defined by the equation:
where I is the generator rated current and K is the negative-sequence (I2
nom
the generator manufacturer.
GEK-113285A
K
=
T
⎛
I 2
⎜ ⎜
⎝
Inom * Ipkp
G650 Generator Protection & Control System
5.4 PROTECTION ELEMENTS
2
⎞
⎟ ⎟
⎠
2
T) capability constant normally provided by
5
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