Research On Temperature Field And Ampacity Of Power Cables

With the development of industry in our country, electric energy has played an increasingly important role in the production and life in recent decades. It has become an indispensable part of human social production and life. As the carrier of electric power transmission, cable circuit is widely used in power generation, transmission, substation and power distribution systems because of its unique advantages. If cables work in overload operation, it will damage the insulation of the cable, long-term in a load running state, will accelerate insulation aging, and ultimately lead to power failure, and even cause fire. During the light load operation of the cable line, the current carrying capacity of the cables is not fully utilized, resulting in the waste of the non-ferrous metal resources. Therefore we must be accurately determine the current carrying capacity of cable, match the cable load flow and power load size, so as to improve the service life of the cable, ensure the safety, reliability and economy of power supply line. Different ways of laying, cable’s ampacity is different, through the establishment the actual laying model of power cables, using numerical analysis theory of cable’s ampacity can be accurate determination of cable line of maximum current carrying capacity.This paper introduced research status of power cable temperature field and ampacity, cable carrying several flow methods to determine and the cable is classified according to different standards, analyzes the basic structure and functions of the cable body. The heat transfer and current carrying capacity of the cable are analyzed in combination with several laying methods used in cable engineering. Based on the theory of numerical analysis, for power cable were electromagnetic analysis, using the ANSYS simulation software, of the buried cable loop to build a physical model, analysis the model of the temperature field distribution, we get the value of three-phase cable core temperature, the cable load flow simulation computation, analysis the different factors influence trend of flow of the loading, summed up the relevant measures to improve the carrying capacity of the cable. At the same time, on cable ampacity calculation was conducted for the system theory, the ANSYS simulation results and theoretical calculation results are comparative analysis, to verify the accuracy of the simulation results, the load flow calculation results and cable manufacturers sample ampacity given values compared that cable product nameplate upload flow margin, according to the engineering experience, the load flow calculation result is credible. Finally, the calculation and analysis of the induction voltage of the metal sheath of the cable line is carried out, and the fire protection measures are introduced, which provides reference for the practical cable engineering.