Design Of HVDC Xlpe Cable Accessories Based On COMSOL Simulation

The power industry plays a decisive role in the economic development.Therefore,it is extremely crucial to ensure that the power is reliably and economically delivered to the load center of power consumption.Compared with the traditional AC transmission system,DC transmission system has the advantages of large transmission capacity,long transmission distance,fast and flexible power regulation,low risk of large-scale chain failure,and reliable system operation.As an important part of HVDC transmission system,HVDC cables are widely used in wind power grid connection,island power supply and long-distance transmission across sea.As one of the key equipment in DC transmission,whether HVDC can operate safely is crucial to the stability of HVDC transmission network.HVDC Cable accessories are the most critical part of DC cable system.Complicated components and processes lead to multiple faults,which has great influence on the stable operation of the system.At present,many theories and methods are put forward for the optimization design of DC cable accessories,which improves the performance of the accessory,especially the failure probability of cable terminal.However,the cable joint is still unstable in the experiment and operation,the article aims at summarizing the previous technical experience,using the new calculation method and theory,completes the simulation design and the analysis verification to the key joint and the test terminal of the DC cable.Based on the experimental research and the material properties of the DC cable accessories,the finite element simulation calculation is used to deepen the analysis.The design of HVDC XLPE cable accessories is completed through actual case analysis and model tests.The experimental study measured the dielectric properties of HVDC cable insulation(XLPE)and accessory insulation(silicone rubber),including the dielectric spectra,electrical conductivity and breakdown field strength as a basis for simulation analysis and structural design.In the part of theoretical research,the most important part of the cable system operation,HVDC cable joint,is firstly analyzed,the temperature distribution and electric field distribution in the joint under transient and steady conditions are analyzed,the characteristic parameters are obtained,and the model is optimized.Secondly,Finally,the actual case analysis and model test verification are carried out to show the problems existing in the design of accessories and their optimization methods in DC cable operation and test.Based on the research of material properties,the thesis bases on the theoretical method and optimizes the design of accessories of ± 320 HVDC cables and test terminal of ± 500 HVDC cables by simulation.The achievement will provide some reference for the development of flexible DC cable transmission system in our country.The simulation calculation method can be applied to the design of DC cable system accessories with higher voltage level such as ± 500 kV.