State Assessment And Maintenance Of 220kV Transmission Lines Based On Big Data Analysis

The operation state of transmission line directly affects the reliability and security of power system.With the development of strong smart grid and ubiquitous power Internet of things in China,it is urgent to find a state evaluation and maintenance method which can reduce the maintenance cost as much as possible based on the transmission line state data.In this paper,big data analysis method will be used to establish transmission line state evaluation model,develop differentiated maintenance strategy,and guide transmission line to carry out state maintenance to meet the requirements of smart grid and ubiquitous power Internet of things.In the aspect of transmission line state evaluation modeling,the method of confidence is used to explore the quantitative relationship between parameters and line failure rate.Based on factor analysis method,a large number of parameters are simplified,and the key parameter system is established according to quantitative ordering.The relative deterioration degree and membership function are used to calculate the failure rate.AHP is used to calculate the weight of the importance degree of each layer and determine the weight coefficient of each parameter and unit.Finally,the state evaluation model of transmission line is formed by weighted accumulation.In the aspect of state evaluation model modification,the established state evaluation model is modified based on the equipment operation life and operation environment,the calculation formula of equipment aging is established,the aging constant is determined according to big data statistics,curve fitting,etc.,and the aging coefficient is calculated by substituting the equipment operation life.According to the impact of environmental factors on the evaluation of line status,special sections are divided,and then the highest defect level of key parameters caused by environmental impact is determined,and the environmental correction coefficient is determined according to the highest defect level.In the aspect of maintenance strategy formulation,according to the evaluation results of transmission line condition evaluation model and comprehensive maintenance cost,the differential classification processing is carried out.The maintenance types are divided into three types,and four types of maintenance time limit are set according to the evaluation results interval.According to the status evaluation results,appropriate maintenance types and reasonable maintenance time limit are selected to carry out maintenance work.In the aspect of case verification,two typical 220kV transmission lines are selected,their equipment account,operation record,fault and defect database and other data are retrieved,their health status is evaluated,and compared with the evaluation results of the existing evaluation system.The final evaluation results are used to select the corresponding type of maintenance,and the health status of the line is evaluated after the maintenance time limit.Based on the analysis of big data and supported by Yantai Power Grid in Shandong Province,an effective state evaluation model of 220kV transmission line in this area is established.On this basis,the maintenance strategy with differentiated function is developed to guide the development of condition based maintenance.