Electric-field Simulation of Insulation Type Test of ±420kV HVDC Flexible Converter Valve

摘要

In order to observe the electric-field distribution of insulation type test of ±420kV flexible converter valve. This work builds the 3D model of ±420kV flexible converter valve tower, Ansoft is used to simulate the electrostatic field. Results show that: when the flexible converter valve is doing a high voltage test, the negative potential in suspension conductors will be generated, the potential distribution degree are various, this phenomenon may be caused by the density difference of electric charges which are induced by different potential between left and right valve components; Results of electric-field simulation for each component suggest that, electric-field concentration likes to appear in the corner of shield and grading ring, and the tip position on capacitor metal component etc., the corner of 1th and 5th layer shields have the maximum electric-field 2×10~6V/m, this value is <3 kV/mm, as for the valve components, the electric-field of 1th～4th layers' valve component are higher than that of the 5th layer's valve component, the reason may be that: because the 5th layer's valve component has a large distance from the top plane (0V), the electric-field lines distribution is sparse, so the electric-field is low; the electric-field value of insulators such as supporting insulators are 10~5V/m order of magnitudes, this is lower compared to the breakdown threshold 2×10~7V/m of insulator materials itself.