Research On Health Assessment And Prediction Method Of Dry-type Distribution Transformer

Dry type distribution transformer is one of the core equipment in the distribution system.Its main function is to transmit and distribute the electric energy.Therefore,its health status will directly affect the safety,stability and economy of the whole system.Overhaul the distribution transformer that has been put into operation can effectively reduce the failure rate and ensure its good health.The traditional regular maintenance mode of distribution transformer may not only cause unnecessary waste of human and material resources,but also lead to the damage of distribution transformer due to the failure of timely troubleshooting or too frequent maintenance.Condition based maintenance can overcome the shortcomings of regular maintenance,but at present,the research on condition based maintenance of distribution transformer in power company is mainly focused on oil immersed distribution transformer,and there is little research on dry-type distribution transformer.In this paper,the health assessment and prediction methods of dry-type distribution transformer are studied.Firstly,the common fault types and causes of dry-type distribution transformer are studied,and the relationship between the operating state and common faults is summarized.The indexes of state quantity that can affect the normal operation of dry-type distribution transformer are classified,and the evaluation standard of each index of state quantity is defined.On this basis,a step-by-step health assessment process is proposed,and the transformer status indicators are classified to form a set of classified and hierarchical health assessment index system for dry-type distribution transformerSecondly,based on Fuzzy Analytic Hierarchy Process(FAHP),the health assessment method of dry-type distribution transformer is studied.The membership function of state quantity index is improved by using health index,and the weight of state quantity index is optimized by introducing equilibrium function.An improved FAHP is proposed,and the evaluation results before and after the improvement are compared and verified by an example.Finally,on the basis of the research on the health assessment method of dry-type distribution transformer,combined with the idea of Monte Carlo state sampling method,Weibull distribution function and normal distribution function are used to describe the change trend of existing state indicators,and then mathematical modeling and random sampling are carried out,the health state prediction model of dry-type distribution transformer based on Monte Carlo method is established,and the validity of the model is verified by an example.