Design Of The Layout And Insulation Structure Of 160kv HVDC Circuit Breaker

In recent years,high voltage DC circuit breaker has become the main technical bottleneck restricting the development of DC power grid,which has attracted wide attention from domestic and foreign scholars.However,the current researches on HVDC circuit breakers are mainly focused on topology study,but there are few research experience of engineering prototype and DC insulation design,which makes it cannot be put into practical operation.Based on the background of the Nan'ao 160 kV DC circuit breaker project,the topology of the coupling type mechanical DC circuit breaker is studied which has high competitive advantage.For the characteristics of multi-component,multiple potential,multi-break series,the research is conducted on the overall layout and insulation structure design,and the Electric Field Simulation research is carried out to validate the correctness of the design.Firstly,based on the PSCAD simulation software,the topology and working principle of the circuit breaker are analyzed in detail.According to the whole insulation requirement of the DC circuit breaker,it is necessary to design the voltage endurance capacity of each component in DC circuit breaker so that the component selection can be completed.On this basis,the overall design scheme of the insulation structure between different potential components in the DC circuit breaker is put forward: the components under high or low voltage are stratified and the modular unified platform is designed.On the basis of the overall scheme,the specific design objects including 21 kinds of air gap and 8 kinds of DC insulators which need to be taken into account in the design are analyzed.The PSCAD software is used to simulate the potential change condition of 9 nodes which are not connected with the ground potential under various working conditions.According to it,the insulation requirement of different design objects can be confirmed.Based on the above results,the external insulation design criteria is studied which is under coastal outdoor environment.According to respective insulation requirements,the minimum clearance of each air gap and insulation height of each insulator can be calculated.And the results are used as the constraints on the spatial relationship between the various components.So that the current design can meet various insulation distance requirements,with a compact structure,which easy to expand to a higher voltage level.According to the characteristics of the large-scale and complex structure of the threedimensional model of the DC circuit breaker,the finite element simulation software ANSYS is used to calculate the electric field of large-scale 3-D HVDC circuit breaker model through appropriate model simplification and reasonable mesh division.Finally,on the basis of the simulation results of DC circuit breaker under typical operating conditions,the rationality of the proposed insulation structure in this paper is verified.Then,the development of DC circuit breaker engineering prototype can be instructed effectively.