导叶开启时间对水电站过渡过程的影响

Influence of wicket opening time on transient process of hydropower station

针对国内外规范对导叶开启时间的不同规定,结合理论推导和数值计算实例,分析了不同的导叶开启时间对水电站过渡过程的影响。实例研究结果表明,大波动过渡过程中的蜗壳动水压力、沿管道轴线的压力分布以及调压室阻抗孔口压差等参数均随导叶开启时间变化而变化。通过研究得到如下结论:国际电工技术委员会标准推荐的增负荷时间30～40s是合理的;在并入小网的水力干扰过渡过程中,需要将运行机组最大初始开度限制在最大临界开度之内,才能保证运行机组转速收敛于额定转速,以满足发电机和电网对调节系统的要求。

The effect of wicket opening time for water turbine on the transient process of hydropower station was studied by theoretical analysis and numerical calculation. The results of two calculation examples illustrate that the dynamic pressure in the spiral case, the pressure distribution along the conduit axis and the pressure difference at resistance orifice of surge tanks during large fluctuation transient process will vary with wicket opening time. It is concluded that: 1. the opening time proposed by International Electrotechnical Commission that the doable value of load augment time must be 30-40 s is reasonable; 2. during the happening of hydraulic interference transient in isolated power network, the maximum initial opening of the operation turbine should be limited within the maximum critical openings to meet the requirements of generator and power network on adjustment system and make the rotation speeds converge at rated value.