Induction generator model in phase coordinates for fault ride-through capability studies of wind turbines

A phase coordinates induction generator model with time varying electrical parameters as influenced by magnetic saturation and rotor deep bar effects, is presented in this paper. The model exhibits a per- phase formulation, uses standard data sheet for characterization of the electrical parameters, is developed in C-code and interfaced with Matlab/Simulink through an S-Function. Saturation uses a direct non-linear magnetizing inductance versus input voltage function. Deep-bar effect is evaluated using voltage reliant correction factors to make both rotor resistance and leakage inductance dependent on the rotor speed. The investigation compares the behaviour of three models in the presence of external faults, namely the "classical" DQ model, a phase coordinates model with constant parameters and the proposed phase coordinates model with time varying rotor and magnetic electrical parameters. Case studies are conducted in a representative sized system and results show aptness of the proposed model over other two models. This approach is also constructive to support grid code requirements.