Research On On-Line Monitoring And Condition Evaluation Method Of Ring Cabinet

The ring network cabinet is the key equipment in the current power grid operation,and the internal cable joint is the most prone to high temperature failure of the ring network cabinet.After years of research,most of the health monitoring of ring network cabinets focuses on the research level of temperature measurement methods,and there is little analysis of potential fault status assessment and early fault warning.Among them,current fluctuations,high current,excessive load,stress cone installation failure and other states are all problems that are prone to occur in the cable joints and arresters in the ring network cabinet,and the harmful impact caused cannot be underestimated.Taking the cable joints and arresters in the ring network cabinet as the research object,and taking the current carrying state assessment and early fault warning based on temperature information as the starting point,this paper is committed to solving the four major state monitoring difficulties of current fluctuation,high current,excessive load and stress cone installation failure of cable joints and arresters,and promotes the development of online monitoring and status assessment research of ring network cabinet.Firstly,the relationship between conductor current and temperature is analyzed,the current-carrying heating mechanism and three basic methods of heat transfer are expounded,and the mathematical relationship between conductor temperature and current is given and verified by numerical simulation.Then,combined with the needs of cable joints and arresters to realize state assessment and early fault warning,taking cable joints and arresters as research objects,analyzing and giving equivalent numerical models,obtaining the temperature field characteristics of each state of current fluctuation,high current,excessive load and stress cone installation fault,and reasonably designing the overall research scheme on this basis.Secondly,through a large number of data analysis and comparison,the three key characteristic information of peak,slope and maximum value of current fluctuation and current high state discrimination are obtained,and the state assessment and early fault warning model for current fluctuation and high current are constructed,and the current fluctuation and high current carrying state monitoring is carried out in laboratory simulation experiments,and the experimental results show that this method can achieve effective evaluation.In addition,based on the GWO-SVR prediction model,the maximum temperature inside the cable joint and arrester under excessive load is analyzed,and the maximum prediction error is 1.7°C and the maximum relative error is 1.89% through simulation experiments,which meets the prediction accuracy requirements of this experiment and realizes internal and external common monitoring.Therefore,based on the temperature information,this paper proposes an online monitoring and status evaluation method for ring network cabinet,and gives an evaluation method for current fluctuation and high current state according to the characteristics of cable joints and arresters,combined with numerical analysis of relative temperature changes.At the same time,a fault monitoring scheme for stress cone installation is proposed;Based on the GWO-SVR model,the maximum temperature inside the cable joint and arrester is predicted,so as to evaluate the state of excessive load,which is feasible in the high temperature prediction direction of the ring network cabinet.The research in this paper promotes the process of online monitoring and condition assessment methods of ring network cabinets,provides a theoretical reference for the actual working condition monitoring of ring network cabinets,and provides certain ideas for the status analysis and early fault warning of related power equipment.