北重阿尔斯通首台600 MW发电机密封油系统特点及问题分析

北重阿尔斯通公司首台600 MW超临界汽轮发电机组,该型发电机的密封瓦为三流环式结构,包括空侧环路、氢侧环路,真空油路。在发电机密封油系统调试及整套启动阶段,发生了空侧密封油差压到零的跳机和氢侧密封油泵频繁跳泵的故障。原因为:空侧油冷油器进口三通阀阀芯装反;空侧密封油差压降低,空侧直流密封油泵自启;密封油回油气泡过多,造成氢侧泵进口油住开关测量为虚假油位。经过相应措施后,基本解决了密封油系统存在的问题,但是回油中含气量超出原设计值,增强回油管道的消泡能力问题还有待解决。

Features and Problems Analysis of Sealing Oil System of Beijing Heavy Alstom First 600 MW Generator

The sealing pads of the first 600 MW turbo-generator (the first 600 MW supercritical pressure generating trait made by ALSTOM Beizhong Power Co.Ltd)are of three-flow ring type configuration,including air side ring loop,hydrogen side ring loop and vacuum oil circuit.In the debugging period of generator sealing oil system and the start-up period of whole unit,tripping-out f allure of generator as a result of air side sealing oil differential pressure dropping to zero and the frequent tripping-out failures of hydrogen side sealing oil pump occurred.The causes were:The valve spool of three-way valve at the inlet of air side oil cooler was installed reversely;air side D.C sealing oil pump self-starting up as a result of dropping of air side sealing oil differential pressure; bubble in the return sealing oil too much,leading to,the switehing measure ment of inlet oil level of hydrogen side pump being false oil level.After the corresponding measures were taken,the problems existing in the sealing oil system have been basically solved but why the gas content in the return oil exceeds the originally designed value,and how to strengthen the bubble-eliminating capability of return oil pipe have not been solved yet.