核电DCC系统冗余CPU电源模块故障分析与技术改进

Fault Analysis and Technical Improvement of Redundant CPU Power Module of Nuclear Power DCC System

通过研究秦山三期核电站DCC系统冗余CPU电源模块的故障多发问题,调查了该型号电源模块多发的原因。考虑到该电源模块的使用环境无明显外界干扰,确定元器件缓慢老化是导致电源模块故障的根本原因。通过失效模式和影响分析方法分析模块的故障原因,得出模块内部DC/DC模块老化损坏导致电源模块失效这一结论。试验证明,DC/DC模块老化会使输出纹波增大,老化严重时产生的短路电流会通过电路线路损坏保险丝,导致电源单元的另一个冗余DC/DC模块承担全部输出。此外,故障严重时会损坏前端的AC/DC模块,使电源单元完全失效,甚至DCC系统下线。

Through the problem of multiple faults in redundant CPU power modules of DCC system in Qinshan nuclear power plant Phase III is studied,the reasons for the frequent occurrence of this type of power module were investigated.Considering that the power module’s use environment has no obvious external interference,it is pointed out that the slow aging of components is the root cause of power module failure.Through the failure mode and the impact analysis method,the failure reason of the module is analyzed, and the conclusion that the internal DC/DC module are damaged and the power module fails.Tests have shown that aging of DC/DC module will increase output ripple,and the short-circuit current generated during the fault will damage the fuse through the circuit line,so that another redundant DC/DC module of the power supply unit will bear all the outputs. In the event of a serious fault,the AC/DC module at the front end is damaged by the circuit line,so that the power supply unit is completely ineffective,and a serious short circuit may even cause the DCC system to go offline.