多基地汽轮机调节系统保护油卸载阀卡涩原因分析

The Cause Analysis of the Protection Oil Unloading Valve Jam Fault of Steam Turbine Governing System in Several Nuclear Power Units

高压调节阀是核电汽轮机的关键设备之一,其动作的可靠性直接影响汽轮机的运行安全。已有10台ALSTOM半速汽轮机投入运行,其中8台机组存在保护油卸载阀(CVS)卡涩导致高压汽阀定期带负荷活动试验失败的问题,且该问题重复发生将对于机组安全运行造成严重影响。基于CVS结构特点,从阀门加工装配质量工艺、表面沉积产物、运行环境等方面,查明CVS频繁卡涩的关键影响因素以及故障机理;针对性地提出CVS装配间隙标准优化、驱动机构维修周期优化、油品漆膜关键指标管控等改进措施。新改进措施在多基地实施,结果表明:高压汽阀定期带负荷活动试验成功率大幅度提高,同时创造了巨大的经济效益。

High pressure regulating valve is one of the key equipment of nuclear power steam turbine,the reliability of its action directly affects the operation safety of steam turbine.Ten ALSTOM half-speed steam turbines have been put into operation.Among them,eight units have the problem that the protection oil unloading valve(CVS)jam leads to the failure of the periodic load activity test of the high-pressure steam valve,and the repeated occurrence of this problem will have a serious impact on the safe operation of the unit.Based on the structural characteristics of CvS,the key influencing factors and failure mechanism of cvS frequent jamming are identified from the aspects of valve processing and assembly quality process,surface deposition products and operating environment.The improvement measures such as CVS assembly gap standard optimization,drive mechanism maintenance cycle optimization and oil paint film key index control are put forward.The new improvement measures are implemented in multiple bases.The results show that the success rate of periodic load activity test of high pressure steam valve is greatly improved,and great economic benefits are created.