电力科技与环保2026，Vol.42Issue(4)：517-528,12.DOI:10.19944/j.eptep.1674-8069.2026.04.001
660MW超超临界双中压缸热电联产机组甩负荷试验转速异常分析及解决措施
Analysis and solutions for abnormal speed during load rejection test of 660 MW ultra-supercritical dual intermediate pressure cylinder cogeneration unit
摘要
Abstract
[Objective]Load rejection test is a core procedure in the startup and acceptance of coal-fired power units,serving to verify dynamic regulation safety under sudden load loss conditions,which directly impacts grid reliability and must strictly comply with industry standards.To address the technical gap in speed control during load rejection for China's first 660 MW ultra-supercritical dual-intermediate-pressure cylinder cogeneration unit,a 50%load rejection test and abnormal mechanism study were conducted.[Methods]In this study,the pre-verification and formal tests of the unit load rejection were completed first.Based on the dynamic energy balance model of the steam turbine rotor and Ebsilon thermal system simulation,the causes of the abnormal speed surge were analyzed,a systematic optimization scheme was proposed,and the effectiveness of the scheme was verified through a repeated test.[Results]In the pre-verification phase,the closing times of 12 key steam valves all met the design requirements,and the main steam valve tightness test,as well as the over-speed protection control(OPC)and electrical overspeed tests,were all qualified.However,in the first formal test,after the unit was disconnected from the grid,the high-pressure and intermediate-pressure regulating valves closed rapidly,yet the maximum speed surged to 3 183 r/min,exceeding 106%of the rated speed,and the test was terminated.The study revealed that the closing time of the butterfly valve in the intermediate pressure cylinder connecting pipe was 850 ms,which failed to meet the design requirements and resulted in continuous work done by the steam;meanwhile,the main and reheat steam temperatures were 62℃and 67℃lower than the design values,and the high-pressure heater(HP heater)was not put into operation,leading to excessive work done by the intermediate and low-pressure cylinders.The coupling of these three factors intensified the speed surge.After optimization,the closing time of the butterfly valve was shortened to 350~370 ms.Meanwhile,the HP heater system was put into operation,and the main and reheat steam temperatures were controlled to be≥590℃.In the repeated 50%load rejection test,the maximum speed of the unit reached 3 135 r/min,which was no more than 105%of the rated speed,the speed stabilized at the rated value within 60 seconds,and all parameters met the specification requirements.[Conclusion]This study reveals for the first time the multi-factor coupling mechanism of speed surge during load rejection of dual intermediate pressure cylinder units.The established technical system of"valve dynamic optimization-thermal parameter matching-system balance regulation"fills the industry gap,provides a replicable scientific paradigm for the safety acceptance of similar high-parameter CHP units,and has important academic value and engineering significance for improving the adaptability of new-type coal-fired power units to extreme working conditions and ensuring the stable operation of the energy and power system.关键词
甩负荷试验/超超临界机组/DEH控制系统/双中压缸/蝶阀Key words
load rejection test/ultra-supercritical unit/DEH control system/dual intermediate pressure cylinder/butterfly valve分类
能源科技引用本文复制引用
章津勖,陈国庆,于强,王晨,陈健,胡耘,蒋国安,何新荣..660MW超超临界双中压缸热电联产机组甩负荷试验转速异常分析及解决措施[J].电力科技与环保,2026,42(4):517-528,12.基金项目
国家能源投资集团有限责任公司科技创新项目(GJNY-23-68) （GJNY-23-68）
国家能源投资集团有限责任公司科技创新项目(GJNY-23-159) （GJNY-23-159）
