Design of a Harmonic Filter for a Grid Connected Doubly Fed Induction Generator under Unsymmetrical Fault Conditions

Abstract

The analysis and controlling of harmonics in a doubly fed induction generator (DFIG) is studied under the unsymmetrical fault conditions in MATLAB/SIMULINK software. The proposed DFIG uses wind energy as the primary source for which is used for power generation. Wind energy is a non-polluting renewable energy resource that is available free of cost but when the wind is used, harmonics are introduced into the power system, so voltage imbalances occur in the grid. In order to mitigate the voltage imbalances (or) ripples in the voltage or current, LCL filters are introduced in the wind turbine because they are chiefly used for high power and low-frequency applications. Various unsymmetrical faults are simulated by referring the specifications selected and analysed with the tripping time for the desired duration of time in the circuit breaker, voltage and current waveforms are analysed only during the transient period on the basis of FFT analysis to know about THD content.