Surface Electric Field Calculation And Structural Optimization Of Valve Hall Fittings Of Uhvdc Converter Station

In pace with strong promotion of the UHVDC construction,the converter station valve hall that is the core part of AC and DC conversion has a significant impact on the safe operation of the entire transmission system.In valve hall,the electromagnetic field distribution is extremely complex,and the electric field distortion and corona discharge of equipment tip are easy to occur.Therefore,the study on surface electric field intensity of the valve hall fittings has an important guiding significance for the construction of converter station.This paper has the following research on valve hall of ±800kV UHV converter station as the main object:According to the connection of high-end valve hall equipment,a full-size model for valve hall is created,which is meshed reasonably.The voltage value of key parts in a frequency cycle as the boundary condition of surface electric field intensity calculation is obtained by the simulation model of ±800kV UHVDC transmission system.The surface electric field intensity of high-end valve hall fittings is calculated with Galerkin boundary element method.The Galerkin boundary element method only needs to mesh the surface of model,which avoids the complicated meshing of 3D model and reduces the meshing difficulty and the calculating cost.The result shows that the maximum electric field intensity of entire valve hall model appears in busbar connection of phase B at the side of low voltage for 14.7kV/cm in this design,and is lower than limiting value of the corona electric field intensity.The method and result of the simulation provide an important reference for design of valve hall fittings.The voltage value of key parts was obtained by the ±800kV UHVDC transmission system for hierarchical connection,and the surface electric field intensity of low voltage valve hall based on UHVDC hierarchical connection to AC is checked.Combined with the electric field simulation results,the electric field distribution of typical fittings in the low voltage valve hall is optimized,and a suitable structure design that is applied to ±800kV valve hall fittings is proposed,which make the surface electric field strength of valve hall fittings at a reasonable level.The calculation result provides data support for the design and construction of UHVDC project for hierarchical connection.