| 绝缘子的基本性能 |
| 添加时间：2018/11/8 14:13:35 浏览次数： |
| 绝缘子的基本性能包括电气、机械和热性能。此外，还有耐环境和耐老化等性能。 The basic properties of insulators include electrical, mechanical and thermal properties. In addition, it also has the properties of environmental resistance and aging resistance. ①电气性能：沿着绝缘表面发生的破坏性放电称为闪络，闪络特性是绝缘子的主要电气性能。对于不同电压等级，绝缘子的耐受电压要求各不相同，其指标有工频干、湿耐压、雷电冲击耐压、雷电冲击截波耐压、操作冲击耐压等。为避免在运行中击穿，绝缘子的击穿电压高于闪络电压。在出厂试验中，可击穿型的瓷绝缘子一般经过火花试验，即加高压使绝缘表面发生频繁的火花，维持一定时间，看是否被击穿。某些绝缘子还需经过电晕试验，无线电干扰试验，局部放电试验和介质损耗试验等。高海拔地区绝缘子，因空气密度下降而使电气强度下降，因此，其耐受电压换算到标准大气条件时应相应提高。污秽绝缘子受潮时的闪络电压大大低于其干、湿闪络电压，因此，污秽地区须加强绝缘或采用耐污型绝缘子，其爬电比距（爬电距与额定电压之比值）应较正常型高。直流绝缘子与交流绝缘子相比较，其电场分布较差，又有吸附污粒和电解作用，闪络电压较低，一般要求有特殊的结构设计和更大的爬电距离。 Electrical performance: The destructive discharge along the insulating surface is called flashover, which is the main electrical performance of insulators. For different voltage levels, insulators have different requirements for withstanding voltage, including dry power frequency, wet withstanding voltage, lightning impulse withstanding voltage, lightning impulse interception withstanding voltage, operation impulse withstanding voltage and so on. In order to avoid breakdown during operation, the breakdown voltage of insulators is higher than flashover voltage. In the factory test, the breakdown type porcelain insulators usually undergo spark test, that is, adding high voltage to make frequent sparks on the insulating surface, and maintain for a certain period of time to see if they are broken down. Some insulators also need to undergo corona test, radio interference test, partial discharge test and dielectric loss test. The electrical strength of insulators in high altitude areas decreases due to the decrease of air density. Therefore, the withstand voltage of insulators should be increased when converted to standard atmospheric conditions. The flashover voltage of polluted insulators is much lower than that of dry and wet insulators when they are wet. Therefore, in polluted areas, it is necessary to strengthen insulation or adopt pollution-resistant insulators, and the creepage ratio (the ratio of creepage distance to rated voltage) should be higher than that of normal insulators. Compared with AC insulators, DC insulators have poorer electric field distribution, adsorption of dirt and electrolysis, lower flashover voltage, and generally require special structure design and larger creepage distance. ②机械性能：绝缘子在运行中常受到导线的重力和张力、风力、覆冰重量、绝缘子自重、导线振动、设备操作机械力、短路电动力、地震和其他机械力的作用。有关标准对机械性能规定有严格的要求。 (2) Mechanical properties: Insulators are often subjected to the action of conductor gravity and tension, wind force, icing weight, insulator self-weight, conductor vibration, equipment operation mechanical force, short-circuit electric force, earthquake and other mechanical forces. The relevant standards have strict requirements for mechanical performance. ③热性能：户外绝缘子要求有耐受温度急变的能力。例如瓷绝缘子要求经几次冷热循环而不开裂。绝缘套管因有电流通过，其零部件和绝缘件的温升以及容许短时电流值均须符合有关标准的规定。 Thermal performance: outdoor insulators require the ability to withstand sudden temperature changes. For example, porcelain insulators require several cycles of cold and heat without cracking. Due to the passage of current in insulating bushing, the temperature rise of its parts and insulating parts and the allowable short-term current value must conform to the relevant standards. |
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