【摘 要】
：
2008年中国南方地区遭受历史罕见的覆冰灾害,绝缘子在低温高湿环境下的覆冰闪络成为电力系统中的频发事故.基于低温下高锰酸钾溶液的冷凝实验可知,冰水相变过程中盐分会发生
【机 构】
：
清华大学深圳研究生院,中国电力科学研究院
论文部分内容阅读
2008年中国南方地区遭受历史罕见的覆冰灾害,绝缘子在低温高湿环境下的覆冰闪络成为电力系统中的频发事故.基于低温下高锰酸钾溶液的冷凝实验可知,冰水相变过程中盐分会发生迁移,过冷却水的凝结由底层向表层逐步发展.洁净绝缘子盐分迁移实验表明,融冰水电导率接近于覆冰水电导率的1.5～2.5倍,冷凝速度愈慢,盐分迁移现象愈明显;表面污秽主要影响底层冰融冰水的电导率,而对表层冰的影响较小.由110kV全尺寸玻璃绝缘子覆冰闪络实验可知,污秽的存在会造成融冰路径的变化,底层冰由于具有较高的含盐量而首先融化,与洁净绝缘子相比,染污0.1mg/cm2的试品泄漏电流在20mA以上的维持时间提高了2.86倍.结果表明:冰水相变前盐分的迁移会改变冰层中的盐分分布状态,引起融冰过程中泄漏电流的升高,这是造成覆冰闪络电压降低的重要原因.
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