Distribution Cable Condition Assessment Based On Multi-source Information

With the expansion of urban scale and the growth of electricity load,cable lines have gradually replaced overhead lines as the main force of urban distribution networks.Cross-linked polyethylene cable is widely used because of its excellent heat resistance,stable operation and excellent electrical performance.However,at present,there is a lack of scientific evaluation of the operating status of the cable,which cannot meet the needs of cable maintenance and elimination.The operation and maintenance management and maintenance of the cable are complicated.Therefore,it is imperative to implement condition-based maintenance based on multi-source information evaluation for distribution cables.Through the monitoring and evaluation of cable status,potential faults can be found in time,and the operation and maintenance management level and power system stability can be improved.The research on the condition evaluation of distribution cable mainly includes the selection of multi-source information parameters,the establishment of evaluation model,the research of multi-source information evaluation algorithm and the design of on-line monitoring system of distribution cable.The selection of multi-source information is analyzed from the various reasons that affect the cable fault,and the parameters that can fully reflect the cable state are selected.Then,according to the selected parameters,a suitable evaluation model is established.By integrating the multi-parameters of the cable into the multi-source information evaluation algorithm,and correcting the problems existing in the algorithm,good results have been achieved.Finally,according to the selected parameters and evaluation algorithm,the online monitoring system of distribution cable is designed.The main research contents of this thesis are as follows :1.Aiming at the problem of inaccurate evaluation results caused by single evaluation factors of distribution cable operation status,through the analysis of the structure and fault causes of the cable,the multi-source information is selected to comprehensively evaluate the status of the cable,and the state evaluation model is established.Simulation and experiment prove the effectiveness of the evaluation model.2.According to the established evaluation model,a multi-source information fusion algorithm based on evidence theory is proposed.Subjective and objective weighting is used to determine the weight of each index,which improves the rationality of weight setting,and introduces the distance between evidence to improve the problem of high conflict of evidence.Through the actual monitoring data of the cable,it is verified that the multi-source information evaluation algorithm can effectively reflect the running state of the cable.3.According to the selected parameters and the improved evaluation algorithm,a set of comprehensive evaluation system for distribution cable condition monitoring is designed.The hardware and software are designed,and a variety of sensors are connected to the terminal.The on-site installation and debugging of the monitoring terminal are completed,and the effectiveness of the online monitoring and evaluation system is verified.