The ultra high voltage reactor bushing is an important equipment to realize the electrical connection between the reactor and the valve tower. High altitude application environment puts forward higher requirement for electrical structure design of reactor bushing. The paper mainly discusses the design of the internal and external insulation structure. The research content are divided into three parts

the calculation of dry arc distance of the bushing porcelain is discussed. The design and analysis of the tail of the

bushing

the corona ring and the inner insulation of the bushing has been done. The three dimensional electric field simulation models have been set up to calculate and analyze the insulation performance of the bushing. The results show that the elevation correction of the external ring and the flashover voltage of the porcelain under high altitude should be done

and the calculation shows that the correction coefficient are 2.07 and 1.36 respectively

and the end of the bushing should install with double type ring.The insulation distance of the hollow porcelain insulator is designed as 8 500 mm. The insulation distance of the bushing tail is designed as 1 955 mm. The maximum field strength of the corona ring is 1.251 kV·mm

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and the maximum field strength on the surface of tail corona ring is 16.962 kV·mm

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. The axial field strength of the bushing core near center conductor is higher than the flange side

and the maximum field strength is 0.55 kV·mm

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. The results of the paper can provide the theoretical basis for the design of the insulation of the reactor transformer bushing used in the UHV transmission project.