中文摘要：

为了给出线路绝缘子不同污秽分布条件下直流污闪电压线性海拔修正系数，便于在海拔≤2km地区直流线路外绝缘的设计，实验研究了在实际海拔1970m条件下绝缘子电弧的发展特性。研究表明：绝缘子上下表面污秽分布情况对瓷绝缘子直流电弧发展路径影响较大，造成直流污闪电压随海拔升高下降的程度不同。通过比较不同海拔高度下（O与2km）210kN钟罩型绝缘子人工污秽试验结果，提出了绝缘子上下表面污秽分布均匀与不均匀两种条件下直流污闪电压线性海拔修正系数分别为6％和3％，并利用大吨位（300kN）钟罩型绝缘子试验结果验证了该线性修正系数。结果表明，该修正系数也适用于大吨位绝缘子。

英文摘要：

In order to put forward the linear correction factor under different contamination distribution condition, this paper presents the results of study on the contamination characteristics of porcelain insulators under uniform and non-uniform contamination distribution conditions in high altitude areas. The arcing behavior on natural polluted insulator surfaces was studied using a PCI 20005 high speed camera. Experimental results indicated that under uniform contamination, DC arcs levitated more easily from the porcelain surfaces, which led to a low utilization ratio of the insulator leakage distance, and made flashover voltage become very low. With non-uniform contamination, the arcs propagated along the insulator surface making full use of the leakage distance, resulting in a higher flashover voltage than with uniform contamination. Consequently, the effect of altitudes on flashover voltage differed greatly in the two different conditions. Flashover characteristics of 210kN anti-fog insulators were investigated with uniform and non-uniform conditions at different altitudes. Two different linear altitudes correction factors of flashover voltages for different contamination conditions were deduced by comparing the experimental results of 210kN anti-fog in- sulators at different altitudes. In addition, flashover characteristics of 300kN anti-fog insulator were also studied at different altitudes. Test results for 300kN anti-fog insulator indicate that the linear relationship is in good agreement with 300kN anti-fog insulator. Therefore, these correction factors can be used in outdoor insulation design for DC transmission projects.