Research On Contamination Characteristics Of Insulators Under The Condition That UHC AC-DC Transmission Line With The Same Tower

It meets the general requirements of building resource-saving society that we set up the tower with multi-circuit transmission line, and it is the most effective way of improving the transmission capacity, saving the investment in the project and line corridor in area of developed economy, expensive land and dense housing. The multi-circuit transmission line on the same tower widely used in the UHV power grid project planned and constructed currently, will be the preferred solution to transmission channel problems in the difficult areas of local. The multi-circuit transmission line with AC-DC on the same tower in the EHV and UHV is in line with the general requirements of constructing resource-saving society, more and more attention has been paid to its insulation. This paper makes the contamination test in the pollution station of natural, and received the contamination of natural data. At the same time, we make a conclusion and comparison between the advantages and disadvantages of kinds of electromagnetic field numerical methods, according to the structural characteristics of insulator strings used in the computational model in this paper and the whole field, we choose the finite element method, calculated electric field distribution using ANSYS software and analyze the natural characteristics of contamination of the insulator in accordance with the natural pollution data. In addition, the computational model of finite element is established based on two circuits, one is the single-circuit transmission line with±800kV DC and the double-circuit transmission line with220kV AC on the same tower, the other one is the single-circuit transmission line with±800kV DC and the double-circuit transmission line with550kV AC on the same tower. And the electric field distribution is calculated, the influence of the electric field from the DC electric field to the insulator near the AC lines has been analyzed. Then the analysis of the results with the combination of electric field calculation and the contamination test of natural indicate that there are different characteristics between the DC and AC insulator surface contamination under the same operating environment, the contamination degree of the former is more severe than the latter; it can’t be ignored that the DC electric field is influential to the surface contamination of the insulator nearby, the distance between the AC insulator and the DC electric field will have an influence on its surface pollution level within a certain range.