秦山第二核电厂离相封闭母线出线箱局部过热问题研究

Study on Partial Overheat of the Isolated Phase Busbar Outlet Box in Qinshan NPP Phase Ⅱ

文章介绍了秦山第二核电厂全连自冷离相封闭母线出线箱的结构,对封闭母线出线箱局部过热的机理进行了研究。研究表明,涡流损耗集中、通风冷却不足是造成出线箱局部过热的根本原因,据此确定了"分散涡流,阻断环流,加强通风"的改进原则,设计制造了新结构的试验出线箱并成功地进行了温升试验。新结构出线箱上箱体各侧面板间、上箱体与下箱体间增加绝缘,上箱体增加两台冷却风机。新结构出线箱投入运行后,热点温度大幅降低,改善了运行环境,保障了机组的安全运行,对同类问题的分析处理具有一定借鉴意义。

This paper recommended the structure of the isolated phase busbar outlet box installed in Qinshan Ⅱ. The study on partial overheat of the outlet box shows that the ultimate causes are the loss of concentrated eddy current and short of cooling. So the improvement principles of ＂distributing eddy current, cutting off inductive circle current and strengthening of ventilation＂ were determined. A new stmcture test outlet box was designed and manufactured, and the temperature rising experiment was carried out. Some alterations were made in the new stmcture outlet box, e.g. isolating materials were added between side plates of the upper outlet box, and also between the upper and lower outlet box. Two cooling blowers were added to the upper outlet box. After putting into operation, the hot-spot temperature of the new outlet box was greatly lowered down. Thus the operation environment was improved, and the operation safety ensured. It can be useful references for analyzing and dealing with similar problems.