The drop of insulation performance of insulator under icing or snow weather is one of the important causes of grid accident. Although domestic and foreign scientists had carried out many researches on icing insulators, the study on snow-covered insulators is relatively lacking. The influence of snow-covered insulators on transmission line insulation safety cannot be ignored. Therefore, it is necessary to study the performance of snow-covered insulators. Generally, there are even snow accretion and uneven snow accretion on insulators. This paper simulates natural snowing environment in the artificial climate chamber. Regarding polluted suspension glass and ceramic insulators, the influences of even and uneven snow accretions on their negative DC flashover characteristics and flashover process are compared. It is shown that the influence of uneven snow accretion on DC flashover characters is greater than that of even snow accretion when the degrees of snow accretion are the same, while in the case of heavier pollution on insulators, the influence of snow accretion shape on insulators deceases, particularly, under severe pollution, the snow accretion shape has no impacts on insulator flashover voltage. The snow flashover process is similar to pollution flashover at the initial stage while similar to ice flashover in the end. With uneven snow accretion, the flashover path develops along the leeward side of insulators.%在覆冰雪环境下,输电线路绝缘子绝缘特性下降是导致电网事故的重要原因之一,目前国内外学者对绝缘子覆冰开展了大量的研究,但对绝缘子覆雪的研究相对缺乏,而绝缘子覆雪对输电线路绝缘安全的影响不可忽视,因此开展对绝缘子覆雪特性的研究十分必要.绝缘子覆雪形态一般分为均匀与不均匀两种,该文在多功能人工气候室内模拟自然覆雪环境,比较悬式污秽玻璃绝缘子与瓷绝缘子两种积雪形态对其直流负极性闪络特性和闪络过程的影响.结果表明:在覆雪程度相同时,不均匀覆雪比均匀覆雪对绝缘子直流闪络影响更大,且随着绝缘子表面的污秽度增加,积雪形态对绝缘子的影响逐渐减小,在重度污秽情况下,覆雪形态对绝缘子闪络的影响趋近于无;绝缘子覆雪闪络过程前期类似污秽闪络,后期类似覆冰闪络,不均匀覆雪绝缘子闪络路径沿着背风面雪层发展.
展开▼
