某核电站主变中性点套管结构设计缺陷分析及改进

Architectural Design Defect Analysis of Neutral Bushing of Main Transformer in a Nuclear Power Station and Its Improvement

某核电站500KV升压变压器在检修完成后在进行本体抽真空处理时,多次发生纯瓷型中性点套管瓷套断裂造成变压器绝缘油外漏的事件,针对此状况,结合变压器油箱结构、中性点套管结构、安装固定方式、抽真空期间变压器油箱应力分布及箱壁变形情况等进行综合分析和计算,提出改进方案,并在现场进行了实施和验证。

After completing the overhaul of the 500KV boost transformer in a nuclear power station,when carrying out the body evacuation treatment,the insulating oil leakage of transformer,which caused by the fracture of the porcelain sleeve of the neutral bushing of pure porcelain type,occurs many times.In view of this situation,combined with the structure of transformer fuel tank,the structure of neutral point bushing,the installation and fixing mode,the stress distribution of transformer oil tank during vacuum pumping and the deformation of tank wall,the comprehensive analysis and calculation are carried out.The improvement scheme is put forward and implemented and verified in the field.