| With the rapid development of The Times,electric power has become an important part of human survival and development,and the security of electric power has also attracted extensive attention from various countries.The main equipment used in power transmission is power cable.The reliability of cable has a decisive influence on the overall stability of power system.Nowadays,XLPE is the most widely used power cable material in the world.The aging degree of cable insulation material in the use process directly determines the service life of the cable.During the aging of cable insulation,temperature,as a major factor,directly determines the aging speed.A basic parameter on the power cable is the load rate.If the load rate is high,the overload problem will occur to the cable,which will increase the temperature of the cable and accelerate the aging speed.Excessive cable temperature indicates that the cable has a fault or a large load,which directly threatens the stable transmission of electric power.It can be seen that if the real-time temperature of cable operation is mastered,the operation process of the cable system can be ensured to be more reliable and safe.Cross-linked polythene cable for single core,the author of this paper,first introduced the structure and composition of crosslinked polyethylene cable,know the cable heating and heat transfer principle,using the theory of heat transfer,the thorough analysis,single core cable temperature field by finite element software cable temperature field simulation calculation,get the steady state under the cable temperature field distribution of the radial,studies the current carrying capacity in different,contact resistance,environmental temperature,insulation condition,the influence of temperature field in cable can obtain cable distribution curve of temperature under various conditions,using the simulation technology to master the cable core and outer skin temperature presents a linear correlation trend,It lays a foundation for the subsequent inversion calculation.Then in view of the cable core temperature cannot directly calculate the reality problem,according to cable temperature field distribution,the establishment of a cable ontology transient thermal path model and simplified equivalent,thermal resistance and heat capacity is put forward based on the parameters of the cable core 2transient thermal order road model and arithmetic circuits,transient thermal path model calculation formula of the electric circuit analysis,obtained a kind of simple and feasible,using coefficient inversion monitoring forecast core temperature of cable core temperature inversion algorithm.To test and verify the accuracy and effectiveness of the simulation and inversion algorithm,designed and built a set of cable temperature rise test platform,cable surface temperature detection method is analyzed,followed by a cable,experimental study on the temperature distribution through the contrast test of single core cable steady temperature and the simulation model for temperature,the error,the scope of the permit test verifies the correctness of the simulation calculation.At the same time,the difference between the temperature of the cable core and the temperature of the outer surface and the ambient temperature is obtained,and the temperature monitoring points are selected reasonably.Then,the inversion algorithm is applied to calculate the temperature of the cable core.The conclusion that the inversion algorithm is suitable for both the steady state and the transient state is obtained,which verifies the correctness and effectiveness of the inversion algorithm. |
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