Research On State Assessment Method Of Subway 35kV Switchgear Based On Multi-feature Fusion

In recent years,the rail transit industry has developed rapidly,and many regions in the country are vigorously building subways.The health status of 35 kV switchgear in rail transit power system is very important for the safe operation of metro.At present,the maintenance method of 35 kV switchgear in subway is regular maintenance.With the increase of subway stations,the number of switchgear is also increasing.Regular maintenance cannot achieve the task of timely maintenance and defect elimination for all equipment,which makes the power supply reliability of subway reduced for equipment with hidden dangers or defects.Aiming at the problems of insufficient utilization of historical data of35 kV switchgear,single feature state evaluation and inaccurate overall equipment state evaluation,this paper proposes a study on the state evaluation method of 35 kV switchgear based on multi feature fusion.It can not only more accurately assess the health status of the switch cabinet,but also judge the health status of important parts such as circuit breakers,busbars and cables inside the open cabinet,and carry out targeted maintenance and defect elimination for equipment with potential safety hazards,so as to improve the maintenance efficiency and ensure the safety and reliability of subway power supply.The research object of this paper is a 35 kV switch cabinet with the model of 8DA10 in a substation of Shanghai Metro.The operation data of the switch cabinet is obtained through PSCADA online monitoring,power outage maintenance test and staff inspection.Considering the characteristics of equipment installation and operation,16 characteristic quantities that can represent the health status of the switch cabinet are selected.The data of the characteristic quantities are normalized,and an improved spatial hierarchical structure model of the switch cabinet is constructed by combining the analytic hierarchy process,The trigonometric fuzzy number method is used to determine the constant weight of the TEV detection value,ultrasonic value,cable joint temperature,busbar temperature and other characteristics of the switch cabinet,and then the variable weight method is introduced to ensure the balance of the state evaluation.Finally,the health status of the switch cabinet is evaluated by solving the correlation degree in combination with the improved matter-element extension theory.The evaluation process is demonstrated by an example,and compared with the traditional correlation function evaluation results,it proves that the proposed method is true and effective for the health status evaluation of switchgear.