Research On State Evaluation Of Power Distribution Equipment Based On Health Index

With the expansion of the scale of smart grids and the continuous improvement of power supply reliability requirements,the maintenance mode has gradually changed from regular maintenance and after-sales maintenance to state-of-the-art maintenance.The condition assessment of equipment is the prerequisite for state-of-the-art maintenance and is an important reference for formulating maintenance strategies.As the terminal system of the power system,the health of the distribution network and its equipment has received extensive attention.The health of power distribution equipment is not only related to its own insulation aging,but also inseparable from its working environment and operating conditions.However,in the past research on the status evaluation of power distribution equipment,the health of the equipment was artificially evaluated based on the number of failures counted in the history of the equipment or the evaluation guidelines for the status of the distribution network equipment,which could not reflect the current true state of the equipment,that is,it was difficult to formulate economics reasonable maintenance measures.This paper introduces the health index(HI)as an index to evaluate the health status of the main equipment in the distribution network to characterize the true health status of the equipment.Firstly,the relationship between the common equipment failure rate and the running time and the graph are introduced.Based on the P-P diagram of the three distribution models,the Weibull distribution model is selected as the equipment failure rate calculation model.At the same time,the service age regression theory is introduced,and the influence of maintenance on equipment failure rate is explained.And focus on the estimation of Weibull distribution parameters based on the fault instance data of the transformer,and establish the calculation model of the transformer failure rate based on Weibull.Secondly,by analyzing the various factors that affect the health status of the actual power distribution equipment,the Analytic Hierarchy Process(AHP)method is used to give each factor a reasonable weight;based on the mapping relationship between the equipment failure rate and the health index,comprehensive consideration of the main power distribution equipment A failure rate correction model was established for factors such as operating time,operating status,and working environment;referring to the functional relationship between the power equipment health index and the failure rate,a power distribution equipment health index evaluation model considering multiple factors was constructed,and an example was adopted.The health status of key equipment in the actual distribution network is analyzed,and the health index of the equipment is given.The results show that the power distribution equipment state evaluation model proposed in this paper has intuitive results when evaluating the health state of the equipment,which is conducive to the flexible formulation of maintenance strategies.Finally,based on the equipment health index,the network equivalence method and the success flow method are used to establish a distribution network health index model,and the impact of changes in the equipment health index at different levels of the system on the health of the distribution network is analyzed.