Research On Fault Diagnosis Of Stator Winding Inter-turn Short Circuit Fault Of Doubly-fed Induction Generator Under Unbalanced Voltage

At present,the doubly-fed induction generator(DFIG),as one of the main model of wind power is paid attention to by the people,because of the bad running environment of DFIG,and long time operation,the malfunction probability is bigger,the stator winding inter-turn short circuit fault is a major cause of winding fault,And the probability of this kind of fault is bigger,such as can't effectively diagnose the faults in time,will cause great damage to the motor itself.At this stage,the fault diagnosis of stator winding inter turn short circuit fault of DFIG is mainly studied by monitoring the change of two aspects of the electrical quantity and non-electric quantity.However,most of these methods are in the condition of power network voltage balance,and there is little research on the fault diagnosis of stator winding inter turn short circuit fault of DFIG under unbalanced voltage.Based on the multi loop theory,this paper establishes the mathematical model of the normal and inter turn short circuit fault in the stator winding of DFIG under unbalanced voltage and unbalanced conditions.In this paper,the concept and process of negative sequence apparent impedance is introduced,and analysis of sources of relevant negative sequence components.From the theoretical analysis of the obtained voltage unbalance without inter-turn short circuit and voltage balance of stator winding inter turn short circuit fault of a DFIG rotor phase current spectrum characteristics,and the two kinds of afore-mentioned circumstances and unbalanced voltage occurred stator winding inter-turn short circuit fault are simulated.The data obtained from the simulation are processed by vector graphic method to obtain the relevant negative sequence components,waveform analysis of the obtained phase current,and the negative sequence component is obtained by using the method of vector graphic.Using the phase current of stator phase current waveform figure and rotor frequency spectrum analysis method,the negative sequence apparent impedance method and negative sequence current method research under unbalanced voltage DFIG stator winding inter-turn short circuit fault.Simulation results verify the correctness of the above three methods for further research of unbalanced voltages DFIG stator winding fault diagnosis method of providing a certain reference value.