The Analysis System Of Transformer Insulation Aging Based On Polarization And Depolarization Current

Transformer is one of the most important equipment in power system,which takes the responsibility of energy transfer and voltage conversion.Its status affects the operation safety of power system.In the event of a fault,it will cause huge losses.Transformer insulation aging is one of the important reasons that cause transformer failure.The transformer insulation is not only influenced by normal operation of the loss,but also by the electrical,thermal,mechanical and external interference.Therefore,the effective and accurate assessment of the transformer insulation state can not only prevent potential faults of the transformer,improve the stability of the power system,but also maximize the service life of the transformer and reduce the operating cost of the power grid,so it is significant.Firstly,dielectric response is introduced.According to the principle of dielectric response,the time-domain polarization process of dielectric response is analyzed to obtain the derivation method of the conductivity of the transformer.The dielectric loss angle formula is obtained according to the dielectric frequency response,which reflects the polarization degree of the dielectric.The polarization type of dielectric polarization process is studied,the various types of polarization reaction time and influencing factors is summarized.These theories lay the theoretical foundation for polarization depolarization experiments.Secondly,this paper presents the identification method of extended Debye model parameter based on chicken swarm optimization algorithm.Chicken swarm optimization algorithm is introduced and the advantages of the algorithm are summarized,such as fast convergence speed and not easy to fall into the local extreme point.It is proposed that using the logarithmic error function of depolarization current as fitness function of flock algorithm can enlarge error of the current wave tail and identify the extended Debye model parameters corresponding to the identification curve.Finally,the simulation experiments show that the algorithm has high precision and meets the requirements of parameter analysis.Finally,this paper designs a transformer insulation aging analysis system based on polarization depolarization current.A testing platform integrated with software and hardware was set up,which tested transformer to obtain the polarization depolarization current.The Debye model parameters of the depolarization curve were identified by chicken swarm optimization algorithm.The results evaluated the paper insulation aging state.Test interface is designed,it can analyze transformer insulation status with the conductivity region based on operating life.The results show that the system has high accuracy and speed of analysis,and has good guiding significance for transformer maintenance.