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Analysis on Stator Circulating Current Characteristics Under Rotor Short Circuit Faults of Turbo-generator

2010; Science Press; Linguagem: Inglês

1003-6520

Yonggang Li,

Magnetic Bearings and Levitation Dynamics

The rotor winding turn-to-turn short circuit fault is one of the main electrical faults of turbo-generators. The stator wingding parallel branches circulating current characteristics under normal condition and the fault were analyzed in order to monitor and diagnose the fault,and a diagnosis method for the fault based on the circulating current characteristics was put forward. Firstly,the turbo-generator parameters were analyzed under normal condition and the fault,viz. air-gap magnetomotive force,the magnetic permeability,the magnetic flux density. Secondly,the instantaneous electric potential equation of each stator parallel branch and the instantaneous electric potential difference between the two stator parallel branches was further deduced. Then,through analyzing the developing trend relationship between the harmonic circulating current and the fault parameters,the circulating current characteristics were investigated under the fault. The results show that the second harmonic circulating current increases when the rotor winding turn-to-turn short circuit fault occurs. Finally,the circulating current of a type SDF-9 generator was measured in laboratory to verify the theoretical analysis presented above.