高水头混流式水轮机过速保护研究  

Research on overspeed protection of high-head Francis turbine

作　　者：沈钊根 叶志强 SHEN Zhao-gen;YE Zhi-qiang(Zhejiang Fuchunjiang Hydropower Equipment Co.,Ltd.,Hangzhou 311121,China)

机构地区：[1]浙江富春江水电设备有限公司,浙江杭州311121

出　　处：《水电站机电技术》2021年第6期1-3,112,共4页Mechanical & Electrical Technique of Hydropower Station

摘　　要：高水头混流式水轮发电机组,引水系统长,机组尺寸小,转速高。为控制发电机转子的线速度,因而其发电机的转动惯量小,导致甩负荷时的转速上升最大值与水轮机的稳态最大飞逸转速很接近,有时甚至高于水轮机的最大稳态飞逸转速。通过加大引水系统尺寸或加大发电机的转动惯量来降低过渡过程时的过速值,经济性和技术性均很差。如何在这种高水头混流式水轮机特有的特性下,成功地实现水轮发电机组的二级保护,同时实现电网要求的甩负荷不出现事故停机要求?本文以一国外电站为实例,重点论述高水头混流式水轮机的调节保证计算的结果及水轮机各水头出力下的飞逸转速特性,按不同电网及电站的实际运行要求,提出可选择性的解决方案,对国内外水电站的高水头混流式水轮机的二级过速保护设计具有一定的参考意义。The high-head Francis turbine generators unit have long water diversion systems,small unit sizes,and high speeds.In order to control the linear speed of the generator rotor,the rotational inertia of the generator is small,which leads to the maximum value of speed rise during load rejection close to the maximum steady-state runaway speed of the turbine,and sometimes even higher than the maximum steady-state runaway speed of the turbine.By increasing the size of the water diversion system or the rotational inertia of the generator to reduce the overspeed value during the transition process,the economy and technology are very unsatisfactory.How to successfully realize the secondary protection of the hydro—generator unit under the unique characteristics of this high—head Francis turbine,and at the same time realize the load rejection required by the power grid without accident shutdown requirements?Taking a foreign power station as an example,this paper focuses on the calculation results of the regulation guarantee of high-head Francis turbine and the runaway speed characteristics of output power of the turbine under each head.According to the actual operation requirements of different power grids and stations,alternative solutions are proposed,it could be a reference for the design of secondary overspeed protection of high-head Francis turbines in domestic and foreign hydropower plants.

关 键 词：高水头混流式水轮机 二级机械过速保护 二级电气过速保护 飞逸转速 

分 类 号：TV734.2[水利工程—水利水电工程]