Influence Of Voltage Fluctuation On Rotor Broken Bar Fault Detection Of Asynchronous Motor

At present,the asynchronous motor is the most important electrical load in the power system.On the one hand,the accurate detection of its fault has become an urgent problem to be solved.On the other hand,the introduction of a large number of power electronic equipment in the power system and the grid connection of new energy power generation system have resulted in increasingly serious voltage fluctuations.Therefore,it is of great significance to explore the influence of voltage fluctuation on the accuracy of motor fault detection.The specific research contents and results are as follows:Firstly,this paper researched the influence of voltage fluctuation on the fault detection method of rotor broken bar of asynchronous motor.Based on instantaneous reactive power signal analysis,the rotor bar fault detection method of asynchronous motor is presented.It is pointed out that the frequency component of amplitude modulation wave would be reflected in the instantaneous reactive power signal spectrum when the voltage fluctuates,and the accuracy of this kind of detection method would be adversely affected.And the correctness of the conclusion was verified by data simulation and experiment.Secondly,determine the threshold that affects the detection accuracy of the rotor broken bar fault of asynchronous motor.The fluctuation signal from the original voltage signal is extracted by singular value decomposition technique and Frobenius norm ratio method,and the concept of voltage fluctuation coefficient is proposed to quantify the magnitude of voltage fluctuation.The coefficient can also reflect the influence of voltage fluctuation on this kind of detection method;Furthermore,the threshold value of voltage fluctuation coefficient of asynchronous motor is derived based on whether it affects this kind of detection method.Finally,a fault detection method for asynchronous motor rotor broken bars which can immune to power supply voltage fluctuations has been proposed.Before the fault detection of broken rotor bars based on instantaneous reactive power signal analysis,the voltage signal fluctuation analysis is done to determine whether the voltage fluctuation affects the fault detection,which makes the traditional method more reliable.The data simulation and experimental results prove that this method is feasible.Compared to the traditional rotor bar fault detection method of asynchronous motor,this paper has considered the influence of voltage fluctuation.This method has engineering application value which can not only be used to improve the reliability of traditional detection technology but also broaden the research idea of the influence of voltage fluctuation on fault detection of asynchronous motor.