锅炉安全阀保护装置的改造

Retrofit of safety valve protection of boiler

广州发电厂 3号炉直流接地 ,主汽安全阀失电后误动打开 ,运行人员在控制室无法远控关闭安全阀。事故的主要原因是安全阀保护的设计有缺陷 ,电磁铁制作工艺差 ,安全阀起跳和回座的整定值与运行额定值相重叠。针对此情况 ,修改了原设计图 ,更换了性能好的电磁铁 ,修改了整定值 ,使运行额定值与回座值错开 ,避免电接点压力表触点打火。改造后 ,经过一年多的考验 ,运行稳定可靠。

Unit 3 boiler in Guangzhou Power Plant experienced DC ground fault; the main steam safety valve misopened after loss of electricity and could not be teleclosed by operators in control room. The accident was main ly due to the defect in the design of safety valve protection, the poor making o f the electromagnet as well as the overlap of the service rating and the setting for safety valve popping and reseating. Consequently, the original design diagr am was amended, quality electromagnet was used and the settings were modified an d made non-overlapping to prevent electric contact ignition of pressure meter. Satisfactory operation results were obtained after the retrofit.