Research On Health Status Assessment Method Of Distribution Transformer

The distribution transformer undertakes the tasks of transforming voltage,distributing and transmitting electric energy in the distribution network,and its smooth operation is related to the safety of the entire power system.Then there are many distribution transformers and various types.In the actual operation process,they are easily affected by various factors,resulting in the occurrence of distribution transformer failures.Therefore,in order to ensure the safe and stable operation of distribution transformers,the health assessment of its operating status is extremely critical.This topic is to evaluate the health status of distribution transformers.The main work and research results are as follows:(1)It is proposed to use fuzzy Delphi method to screen the index parameters of distribution transformers,and to construct an index system for evaluating the health status of distribution transformers.The fuzzy Delphi method is used to screen the evaluation indexes of distribution transformers by component,and the set of key index parameters of distribution transformers is determined,including quantitative indexes,qualitative indexes and monitoring indexes.(2)Identify abnormal monitoring data of distribution transformers based on sliding windows.Under the common constraints of the mean value and the adjacent difference value under normal circumstances,the abnormal data set is found in each sliding window,and the abnormal data type is judged,and the identified valid abnormal data interval is used for the subsequent health status evaluation of the distribution transformer.(3)A method for evaluating the health status of distribution transformers based on multi-information fusion is proposed.Combined with quantitative data,qualitative data and monitoring data,the constant weight of the indicators is calculated by the AHP method,and the degraded variable weight of the indicators is calculated by introducing the equilibrium function combined with the constant weight,so as to build a set pair analysis and improve the evidence theory of distribution transformer health Evaluate the model.The comprehensive connection degree of the set pair analysis and calculation index layer is used as an independent evidence body,and the evidence body is modified by improving the evidence theory and introducing the evidence deterioration factor and the timeliness factor.Then,the synthetic rules are used to integrate the information of quantitative indicators,qualitative indicators and monitoring indicators,and the comprehensive decision-making criteria are used to evaluate the health of distribution transformers.The feasibility of the health state assessment method proposed in this paper is verified through comparative analysis of examples.(4)Based on the health status assessment results of the distribution transformers over the years,the life expectancy is predicted.Using the obtained health index of distribution transformers over the years,two models of GM(1,1)and ARIMA are used to fit and predict the remaining life of distribution transformers,and the prediction effect of the model is judged according to the relative error.Through example simulation,the GM(1,1)model is preferred to predict the health index of distribution transformers in the future.