Research On Chaotic Mechanism Of Air Gap Partial Discharge In Solid Insulating Materials

It is a common phenomenon that partial discharge occurs in electrical equipment due to defects such as air gap in insulating materials.With the development of partial discharge,insulation breakdown will eventually occur.At present,many scholars have carried out a lot of research on the use of chaotic characteristics of partial discharge for discharge identification and insulation diagnosis,but there are relatively few studies on the causes of chaotic characteristics of partial discharge,so it is hard to systematically establish the relationship between chaotic characteristics and partial discharge characteristics.In order to better play the guiding role of chaotic characteristics of partial discharge in the diagnosis of insulation deterioration,It is necessary to study the mechanism affecting the chaotic phenomenon of partial discharge.In this paper,based on the concept and characteristics of chaotic systems,the characteristics and characterization of chaotic systems are introduced,and the correlation between chaotic systems and partial discharge is preliminarily analyzed.In order to study the main physical mechanism leading to chaos in the process of partial discharge,this paper conducts modeling and simulation of small spherical air gap partial discharge under flat electrode based on the concept of induced charge.In the model,the positive and negative feedback of space charge field,discharge delay and the influence of random factors on discharge are comprehensively considered.The simulation results are consistent with the experimental results of other scholars.The accuracy of the model is verified.Based on the partial discharge model,the feedback of space charge to the electric field generated by discharge in the air gap,the feedback of space charge to the electric field and the discharge delay,and the influence of random factors based on the feedback on the partial discharge behavior are studied respectively.The chaotic characteristics of partial discharge are characterized qualitatively by constructing the time series diagram of reversed polarity apparent discharge and the attractors of different parameter time series.The results show that the feedback mechanism of space charge to electric field and discharge delay can lead to chaotic phenomena of partial discharge,and the asymmetry of positive and negative feedback is the main reason for the chaotic characteristics of partial discharge.Randomness is not a necessary condition for the chaotic character of the local amplifier,but it will interfere with the inherent chaotic character of the local amplifier itself.Based on the simulated discharge time series,the maximum Lyapunov index,correlation dimension and Kolmogorov entropy were calculated under different conditions.Combined with the simulated discharge parameters,the influence of feedback mechanism on the chaotic characteristics of partial discharge was quantitatively studied.The results show that,considering the feedback of space charge to electric field and discharge delay,the amount of discharge and the decay rate of space charge affect the chaotic characteristics of partial discharge,and the rapid decay rate of space charge will weaken the chaotic characteristics.In addition,the positive feedback in the discharge process is the main reason for the aggravated complexity of partial discharge.The larger the asymmetry between positive and negative feedback is,the more obvious the chaotic characteristics of partial discharge are.