用电负荷增加引起的绝缘加速老化与电气火灾

Accelerated Insulation Aging Due to Increase of Electrical Load and Electrical Fire

导体绝缘老化如果得不到及时维护会导致短路或接地故障从而引发火灾。导体的绝缘老化有多种原因,如长时间通过过负荷电流会使导体超过最高运行温度并加速绝缘老化。但在某些情况下,用电负荷增加时线路过负荷保护却不能避免导体超过最高运行温度。本文分析线路负荷电流、断路器额定电流、导体允许持续载流量和绝缘加速老化之间的关系,提出配电线路设计时需注意的问题和处理的方法。

If the conductor insulation aging cannot timely maintained,it will lead to a short circuit or grounding fault which can cause a fire. There are a variety of causes for conductor insulation aging,for example,prolonged over-load current through the conductor would exceed the maximum operating temperature and speed up the insulation aging. However,in some cases,the over-load protection cannot avoid that the conductor exceeds the maximum operating temperature when the electrical load increases. By analysis of the relationship between the circuit load current,the rated current of the circuit breaker,the allowable continuous current-carrying capacity of the conductor and accelerated insulation aging,the problems that should be paid attention to and the treatment methods are proposed for the design of distribution lines.