摩擦对水力机组大波动过渡过程影响研究
2016-01-13叶文波王煜于凤荣姜峰余国锋张云
叶文波+王煜+于凤荣+姜峰+余国锋+张云龙+蒋百超

摘 要: 运用MATLAB/Simulink软件对考虑摩擦和不考虑摩擦时一台水力机组在额定工况下甩负荷运行后的大波动过渡过程的仿真结果进行了比较,讨论了摩擦对电站甩负荷后的蜗壳末端水击压力、尾水管末端转速及水轮机真空度等因素的影响,进而为水电站在大波动调保计算时是否考虑摩擦的影响提供一定程度的参考.理论分析表明,摩擦对大波动过渡过程存在一定影响,但是在一定条件下,这种影响可忽略.仿真结果表明,不考虑摩擦时的水击压力和转速都略大于考虑摩擦时的水击压力和转速.对实际工程而言,这种偏大的计算结果是安全的.
关键词: 水力机组; 摩擦; 大波动; 仿真; 调保计算
中图分类号: TV 136 文献标志码: A
Influence of friction on the large oscillation transient
process of hydraulic unit
YE Wenbo, WANG Yu, YU Fengrong, JIANG Feng, YU Guofeng,
ZHANG Yunlong, JIANG Baichao
(Faculty of Metallurgical and Energy Engineering, Kunming University of
Science and Technology, Kunming 650093, China)
Abstract: Using the MATLAB/Simulink software, the simulation results of large oscillation transient process of one hydraulic unit under the rated condition were compared when the friction was considered or not. The influence of friction on the speed and pressure of hydraulic turbine after load shedding was discussed. The results can provide reference for calculation of regulating guarantee under large oscillation transient process. The theoretical analysis indicates that the friction has some influence on the large oscillation transient process, but this influence can be ignored. The simulation results show that the pressure and speed with no friction are higher than those with the friction, which is safe in terms of projects.
Keywords: hydraulic unit; friction; large oscillation; simulation; calculation of regulating guarantee
水电站过渡过程,尤其是大波动过渡过程,虽然历时短暂,但伴随着工况参数大幅度急剧变化[1].大波动过渡过程的本质是水击波的传播过程[2].在甩负荷时,水轮机流量的急剧变化会引起压力水管末端流量的急剧变化,水管内将出现非恒定流现象,从而使水轮机压力过水系统产生水击,同时由甩负荷引起的转速升高会对机组、厂房的安全造成威胁.调保计算的任务是保证压力和转速的升高不超过允许值.调保计算中所涉及的数学模型、计算过程都会考虑摩擦因素的影响.由摩擦造成的能量消耗使水锤波在管道中的传播不再是一个振幅不变的持续震荡过程……
