IEC61439-1:2020的加热措施能防止凝露吗?--基于事实和理论的探讨

Do the Heating Measures in IEC 61439-1:2020 Prevent Condensation?--Exploration Based on Facts and Theories

为探讨《IEC 61439-1:2020 Low-voltage switchgear and controlgear assemblies-Part 1:General rules》内部加热措施对防止封闭空腔有害凝露的适用性,采用文献研究方法对经验事实初步分析。结果显示,内部加热措施被采用最多,但实施效果不佳,没有发现任何实际案例严格确证内部加热措施能防止有害凝露;一些案例还表明,内部加热诱发或加重凝露;还存在一些令人困惑的案例:内部已明显凝露、加热装置未启动。根据热力学理论和最新发现的热湿度效应规律,结合事实深入分析讨论。结论表明:IEC 61439-1:2020的封闭空腔内部加热措施不能防止有害凝露;热力学关于湿空气过程理论不适用于该过程分析。封闭空腔内部加热过程实际遵循热湿效应,这势必增加凝露风险。

In order to explore the applicability of internal heating measures to prevent harmful condensation in enclosed cavities in IEC 61439-1:2020 Low-voltage switchgear and control gear assemblies-Part 1:General rules,this paper uses the method of literature research to make a preliminarily analysis on the empirical facts.The results showed that internal heating measures are most commonly used,but the implementation effect is not good,and that no actual cases are found to strictly confirm that internal heating measures can prevent harmful condensation.Some cases also indicate that internal heating induces or aggravates condensation.There are also some confusing cases:the interior has been visibly condensed,and the heating device has not been activated.In addition,according to the theory of thermodynamics and the newly discovered law of heat and humidity effect,the paper combines with the facts to make an in-depth analysis and discussion.The conclusion shows that the internal heating measures in the closed cavity of IEC 61439-1:2020 cannot prevent harmful condensation,that the thermodynamic theory regarding wet air process is not applicable to the analysis of this process,and that the heating process inside the closed cavity actually follows the heat and humidity effect,which inevitably increases the risk of condensation.