Simulation Analysis And Optimization Design Of 320kV XLPE Cable And Terminal Accessory

Flexible HVDC transmission is an important part of smart grid.Compared with the traditional power transmission,flexible HVDC has received extensive attention in the areas of island transmission,submarine cable,long-distance power transmission,AC and DC power supply,new energy and so on.HVDC cable system as a part of flexible HVDC is of important value.In order to promote the localization process of high voltage DC cables and the development of HVDC power cable transmission,this paper designs and analyzes the 320 kV XLPE DC cable and its terminal accessories on the theoretical analysis and simulation optimization and experimental test.First of all,in the theoretical analysis,this paper has calculated the dimension parameters and design requirements of each layer of 320 kV high voltage DC cable.It focuses on the analysis of the thickness of the XLPE insulation layer design.It caculates the steady state design strength and the pulse design field strength.Finally,it is concluded that the size of insulating layer is based on the design of domestic nanometer XLPE.At the same time,the structure and size of the terminal accessories are optimized in this paper.And the calculation of the parameters of the stress cone and the umbrella skirt are analyzed from the theoretical point of view.Then,in the aspect of experimental test,electrical conductivity properties of domestic nano crosslinked polyethylene and silicone rubber are studied by using the three electrode method.Based on the analysis of the data,the relationship between the conductivity of XLPE and SIR is obtained.Based on PEA,the distribution of the internal space charge of the materials with different electric field strength and temperature are studied.The test indicates that domestic material satisfies requires.According to the design structure,the electric field distribution of the 320 kV crosslinked polyethylene cable body is calculated by using the finite element simulation software both in steady state and inversion of field strength.And the electric field distribution in the cable body under the action of impact voltage is simulated and analyzed.Then in the aspect of terminal simulation analysis,the interface tangential field strength in the interior of the terminal is satisfied with the design requirements through optimal design of stress cone,reinforced insulation and insulation shielding layer lap length.In this paper,the 320 kV high voltage DC cable and its terminal accessories are designed from three aspects of theoretical analysis,experimental testing and simulation optimization.The structure parameters of the 320 kV DC cable body are calculated and the terminal attachment structure is designed.The research results of this paper can provide some reference for the design of HVDC cables in China.