双机回热系统抽背式小汽机背压分级控制策略  

Priority Control Strategy for BEST Back Pressure in Double-turbine Echelon Cycle Regenerative System

作　　者：王坚 马栋 付琼 李军锋 张文祥 宋放放 WANG Jian;MA Dong;FU Qiong;LI Junfeng;ZHANG Wenxiang;SONG Fangfang(Central Southern China Electric Power Design Institute Co.,Ltd.,of China Power Engineering Consulting Group,Wuhan Hubei,430071;National Energy Group Yueyang Generation Co.,Ltd.,Yueyang Hunan,414100;Dongfang Turbine Co.,Ltd.,Deyang Sichuan,618000)

机构地区：[1]中国电力工程顾问集团中南电力设计院有限公司,湖北武汉430071 [2]国家能源集团岳阳发电有限公司,湖南岳阳414100 [3]东方电气集团东方汽轮机有限公司,四川德阳618000

出　　处：《东方汽轮机》2024年第4期74-79,共6页Dongfang Turbine

摘　　要：文章提出了1000 MW级一次再热或二次再热机组采用双机回热系统时抽背式小汽机的背压分级控制策略,包括配置了排汽调节阀、中压缸抽汽或辅助蒸汽至混合集箱的补汽管路及调节阀、混合集箱至下一级低加的溢流管路及调节阀、混合集箱至凝汽器的溢流管路及调节阀等背压控制方法;合理设定抽背式小汽机背压的工作范围为0.09~0.72 MPa,启停期间设定值为0.2 MPa。制定了小汽机背压控制措施的优先级,分级使用方法和策略;本文提出的小汽机背压控制方法和策略,同时监控小汽机排汽背压、小汽机末级组、次末级组压比和7、8号低加工作压差多个关键指标,在保持双机回热系统在高参数上的优势的同时,保证抽背式小汽机和各级低加安全运行,保持小机进汽阀全开,减少节流损失和排汽溢流损失,提高运行的经济性。A priority control strategy is proposed on the back pressure regulation of the back pressure extraction steam turbine(BEST)in double-turbine echelon cycle regenerative system power plant.Measures are adopted including control valve on the exhaust piping,replenish steam piping and control valve from auxiliary steam system to the mixing header,overflow valve from the head to next level LP heater,overflow valve from the head to the condenser.The optimized BEST back pressure is chosen to be 0.2 MPa during start and 0.6 MPa during normal operation with the limit from 0.09 MPa to 0.72 MPa.A priority control strategy is proposed with the different control level recommended.The BEST back pressure,pressure ratio between final blades and final blades earlier stage,differential pressure between LP7&LP8 are all should be under supervisory control under this strategy,so as to ensure the safety operation of the BEST&LPs,with the inlet valve full open.Efficiency under variable unit load is improved under this priority strategy.

关 键 词：双机回热系统 抽背式汽轮机 背压 控制策略 优先级 

分 类 号：TK262[动力工程及工程热物理—动力机械及工程]