Research On Electric Field Distribution Characteristics Of Valve-side Outlet Device Of±800kV Converter Transformer

At present,the outlet device of±800kV converter transformer relies on the import,and the ±800kV outlet device is one of the key insulation structures of the converter transformer.It is increasingly important and urgent to study the key technology of the insulation design of the±800kV outlet device.In this paper,the valve side outlet device of±800kV converter transformer is used to study the characteristics of electric field distribution of outlet device under AC and DC electric field,the optimization method of insulation design,and the test method and test scheme of insulation margin of outlet device.The main research work and main results of this paper are as follows:(1)Aiming at the two mainstream outlet devices of "straight-tube" and "different forms",a simulation model for calculating the AC-DC electric field of the line device is established.The calculation of the AC-DC electric field distribution of the device is completed based on Maxwell 2D simulation software.(2)The effects of the thickness of the single layer of the casing plate,the meandering ring diameter and position,and the thickness of the single-layer cardboard board on the electric field distribution were studied.The results show that reducing the thickness of the single-layer plate and increasing the number of layers can reduce the field strength of the first plate of the casing;the electric field strength of the end of the casing is small;the thickness of single-layer cardboard of the screen is small for influence of the electric field strength.(3)According to the demand of power line withstand voltage test,DC withstand voltage test and polarity reversal test of outlet device,combined with inversion boosting method,the test method and test plan for the insulation margin of the outlet device are proposed for the test to find the outlet device.The weak link of the insulation structure,to test the insulation margin requirements of the weak link.In this paper,based on the study of the electric field distribution characteristics of the outlet device under the action of AC and DC electric field,the electric field strengths of the "straight-tube" and "different-form" two-wire outlets are compared and analyzed.The design and optimization of the insulation structure of the outlet device are proposed from various aspects.The ideas and methods have established the test methods and schemes of the test equipment,which has reference and guiding significance for the research and manufacture of the outlet device of±800kV converter transformer.