| Cable line capacity increase is of great significance to cope with the rapid growth of urban electricity demand.In order to ensure the safety of cable line capacity increase,it is necessary to evaluate the current carrying hot spot status of the whole cable line.At present,the cable accessories and many laying environments have abrupt local points which may overheat and become current carrying hot spots.The cable terminal is one of the main components of the current carrying hot spot of the cable line.Due to the need to remove the shielding layer at the end of the cable during its installation,the electric field and temperature field at the fracture of the shielding layer will be distorted,forming a potential threat point of failure.Therefore,it is very important to study the basic distribution characteristics of temperature field and electric field of cable terminal.This paper first introduces the structure of the cable line in the distribution network in detail,focusing on the types of cable terminals and the heating mechanism of cable terminals,and introduces the calculation method of cable loss and heat transfer process.It provides a theoretical basis for the numerical calculation of temperature field and electric field of cable terminal.On this basis,the numerical simulation calculation model of plug in GIS cable terminal(GIS terminal)is established.On the basis of the numerical simulation calculation model,the axial distribution characteristics of temperature field between GIS terminal and cable body are compared and analyzed.The relationship between the maximum temperature of cable core and the temperature difference of insulation layer under different core current carrying and outer surface temperature is proposed.The current carrying capacity and appearance of cable core are discussed The influence of surface temperature on the steady-state temperature field of GIS terminal.The electric field distribution of GIS terminal has become a new problem to be solved in the safe operation and test of cable lines.In order to improve the stability and safety of the operation,this paper analyzes the location where the electric field intensity is relatively concentrated in the cable terminal,and comprehensively considers the actual application environment and production situation of GIS terminal,and puts forward the main insulation,stress cone insulation material and stress cone metal part of GIS terminal The calculation method of the influence of curvature radius and semi conductive shielding layer structure on the electric field distribution provides a theoretical basis for seeking the optimal parameters of electric field distribution in GIS terminal.This paper also built a 110 kV GIS cable terminal high current experimental platform,and measured the temperature distribution of GIS terminal and cable body at different node positions under different load currents,the maximum temperature of core and the temperature difference between GIS terminal and cable body are studied.The axial distribution characteristics of temperature field between GIS terminal and cable body are further summarized and analyzed.The research results of this paper can provide reference for power dispatching and operation and maintenance departments to evaluate the current carrying capacity of cable lines,and provide theoretical support for the optimization of internal structure of GIS cable terminals. |
PDF Full Text Request