冻融循环试验对绝缘子机械性能的影响研究

绝缘子是电力系统中使用量最大的器件,当运行中的任何一片绝缘子出现机械故障,就有可能造成掉串的严重事故,造成不可估量的损失。将4种类型的绝缘子预加不同应力,放入高低温交变试验箱,在绝缘子水泥胶合剂、钢脚和瓷件之间注入少量的纯净水,模拟冻融循环的环境条件,经冻融循环试验后再进行机械破坏负荷试验。研究表明:冻融循环将对A型和C型的绝缘子的机械破坏负荷产生显著影响,其机械破坏负荷随着预加应力增加或冻融循环次数增加而降低;而对于B型和D的绝缘子冻融循环的影响是有限的即冻融循环试验后该类型的绝缘子机械破坏负荷不会出现明显的变化;对于部分钢脚出现松动的D型绝缘子,由于水分子更容易渗透到水泥胶合剂与钢脚之间的裂隙当中,冻融循环试验后,水泥胶合剂性能出现明显的下降,导致绝缘子机械破坏负荷显著降低。

Study on the Influence of Freeze-thaw Cycles Test on the Mechanical Capacity of Insulator

Insulator is the most used device in the overhead transmission line. In the operation, if mechanical fault occurs on any piece of insulator, it may cause serious bunch-drop accidents and cause immeasurable losses. In this paper,4 different types of insulators which are prestressed different stresses were tested in high-low temperature test box. In order to simulate the freeze-thaw cycle condition,between cement compo, steel pin and porcelain, a small amount of pure water was injected. The mechanical failure load test was carried out after the freeze-thaw cycle test. Research shows that: the mechanical failure load of insulators for type A and type C were significantly influenced by freeze-thaw cycle test, and the mechanical failure load of these insulators decreases with the increase of pre-stress or increase in the number of freeze-thaw cycles. But, for the insulator of type B and type D, the effect of freeze-thaw cycles test is unconspicuous, i.e. after freeze-thaw cycle test the mechanical failure load of these insulators don't obviously change. It also needs to be pointed out that for insulator of type D with steel pin loosening;the mechanical failure load was reduced significantly after freeze-thaw cycles test. Because during the freeze-thaw cycles test, the water molecules more easily penetrate into crack between cement compo and steel pin, and the performance of cement compo decreased obviously.