Research On Distribution Network Condition Assessment Based On Health Index

With the popularization and development of smart grid,the maintenance mode of power grid equipment has gradually changed from traditional post fault maintenance and regular maintenance to condition based maintenance.As the premise of condition based maintenance,the importance of equipment condition assessment is self-evident.At present,with the rapid development of health index theory(HI)in China,a comprehensive and detailed state evaluation of distribution equipment and distribution network has been preliminarily realized,but this method weakens the impact of historical fault statistics and past experience on the analysis of health state.In the state evaluation,it is too real-time and pays attention to the comprehensive and detailed state information collection at the current time.When facing a large number of distribution network equipment with wide range and complex operation conditions,Ignoring the universality and operability of condition assessment,it is difficult for the actual operation of power grid staff.It is found that there is a certain correlation between the health index of the equipment and the failure rate.Therefore,based on the mapping relationship between health index and equipment failure rate,this paper proposes a complete method to select the optimal distribution model of distribution equipment failure rate function,which is composed of four parts.Firstly,the equipment fault information in the area is collected,and the information is preprocessed by exponential smoothing method(ES)to filter out the data points with high volatility;Then,find out the time when the equipment enters the loss period from the extreme point of curvature fluctuation,and process the data in sections;Then,five typical distribution models are used to fit the failure rate data in stable period and loss period,and the unknown parameters of various models are determined;Finally,by comparing the fitting effects of various distribution models through K-S test,the equipment life cycle failure rate function under the optimal distribution fitting is obtained.Secondly,this paper analyzes various factors causing equipment failure in actual operation,puts forward a real-time failure rate function model of distribution equipment considering the influence of seasonal and non seasonal factors,comprehensively calculates the regional equipment health index according to the mapping relationship between health index and equipment failure rate,and evaluates the status of equipment.Finally,the health index model of distribution network is established through the idea of network equivalence method and success flow method,and the impact of the fluctuation of health index of various equipment on the whole network under different actual operation states is considered.