Fault Features Study of Doubly Fed Induction Generators on the Stator Windings Turn-to-Turn Short Circuit

Abstract

Doubly fed induction generators (DFIG) are gradually used in wind power generation, and its capacity is becoming bigger and bigger. Turn-to-turn short circuit of winding is common fault in DFIG, and in order to study the steady electromagnetic characteristic of DFIG with the stator windings turn-to-turn short circuit, a simulation model is built based on the finite element method. In order to improve the accuracy, the excitation current in finite element is calculated by multicircuit equation. The proposed model is employed to simulate the magnetic field and current of stator and rotor windings when turn-to-turn short circuits occur on stator windings of DFIG. From the simulated result, we obtained the frequency spectrum of magnetic flux density of air gap, analyzed the difference of magnetic field and line current of stator and rotor windings between faulty and healthy generators, and concluded the feature of stator inter-turn fault in DFIG.