Study on the Flashover Characteristics of Air Gaps for San-Hu II ± 500kv Double Line Transmission Towers

摘要

Flashover characteristics of the upper frame airgaps for ±500kV DC double line transmission towers areresearched by impulse flashover test on real size simulationtower, and the test curves are presented. Tests about Flashovercharacteristics impacts of the lower crossbeam on the upperframe air gaps are carried out, the test curves are given in thispaper under the precondition that the distance of upper line toupper crossbeam and tower body is 4.4m and the distance ofupper line to lower crossbeam is 2.7m-4.2m. Combined with thetest result curves when the upper frame gaps have the samedistance and the correction formula with different tower width,the curves of lower frame air gaps are also given in this paper.Based on the over-voltage and the switching impulse flashovercharacteristics on air gaps, the minimum clearances for the airgaps of upper and lower frame of ±500kV DC double linetransmission towers from the Three Gorges Hydropower Stationto Shanghai are presented.