Research On Detection Method Of Stator Winding Inter-Turn Short Circuit Fault Of DFIG

With the increasingly severe energy crisis and environmental problems,the wind power industry has gained widespread attention and development.For the moment,double-fed induction generators are the mainstream of wind power generation,and the stator winding inter-turn short circuit is one of the common faults of double-fed induction generator.Since the double-fed induction generator is generally remote or offshore and difficult to maintain,if the stator winding inter-turn short circuit fault cannot be detected in time and effectively,the fault will expand and damage the generator itself and the power grid.Therefore,it is of great significance to realize the detection of the stator winding inter-turn short circuit fault of the double-fed induction generator.The main research work completed in this paper is as follows:(1)Based on the multi-loop theory,the variation of inductance parameters before and after the stator winding inter-turn short circuit fault of the double-fed induction generator is analyzed.Based on this,a mathematical model of the double-fed induction generator under normal conditions and the occurrence of stator winding inter-turn short circuit fault is established.(2)From the theoretical point of view,the rotor side spectrum characteristics of the double-fed induction generator under the condition of stator winding inter-turn short circuit fault are analyzed,and the simulation verification is carried out by MATLAB.(3)The high frequency resolution characteristic of the Estimation Of signal parameters via rotational invariance technique(ESPRIT)is used to accurately estimate the frequency of the characteristic component of the rotor current signal,and the extended Prony algorithm is used to determine the frequency components.The amplitude,which forms a new method for detecting the stator winding inter-turn short circuit fault stator winding of the doubly-fed induction generator combined with ESPRIT and extended Prony algorithm.In addition,A new method for detecting the stator winding inter-turn short circuit of the doubly-fed induction generator is proposed by combining the Duffing system signal detection with the APES(Amplitude and Phase EStimation)algorithm.Using the sensitivity of the Duffing system to the initial parameters such as the amplitude of the power,the frequency to be tested and the strong immunity to the background noise,the presence or absence of the fault feature to be tested is judged according to the phase trajectory change.Based on this,the APES algorithm is used to determine the amplitude of the fault feature,which makes up for the insufficiency of the Duffing system to provide accurate amplitude.Comparing these two methods with thetraditional Fast Fourier Transform(FFT)algorithm based stator winding inter-turn fault detection method,the results show that these two methods are convenient and effective,which provides a new idea for the fault detection of doubly-fed induction generator.