Numerical Calculation of Temperature Field and Ampacity of High-voltage Lines Using MATLAB

As more and more power cables are being used in power circuits,identifying the thermal field distribution of power cables and cable ampacity is very important to improve the capacity utilization of power cables so that adequate adjustment of cable loading can be achieved.Consequently,we evaluated the ampacity of XLPE cables laid in duct with pipes,which was 230 kV high voltage power cable in 250 MVA transformer substation.Using the principle of heat transfer theory and finite element method(FEM),we developed a model for power cable thermal field,in which complex triangle finite element was divided as meshes in region,namely,dense meshes in cables and sparse ones in other areas were divided so as to improve the running speed of the program and operation precision.The thermal field of cables and surrounding cables was computed using FEM.The results show that through simulation with MATLAB,the temperature field distribution of the cable and its surroundings are obtained,the ampacity of single XLPE power cable systems are calculated by iteration method,proving that FEM can be used to analyze temperature field of underground cable system.