轴流转桨式水轮机协联关闭规律选择及优化分析

Selection and Optimization of Blades and Guide Vanes Closing Laws for Kaplan Turbines

合理的水轮机关闭规律对控制水电站水力过渡过程调保参数非常关键,由于桨叶-导叶双调节的存在,轴流转桨式水轮机的关闭规律的选择和优化较为复杂。基于对轴流转桨式机组协联飞逸曲线的特性分析,提出了一种新型导叶桨叶协联关闭规律:机组发生甩负荷时,导叶一段直线或折线关闭,桨叶一段直线开启,结合数值仿真计算分析,验证了该关闭规律能够显著降低蜗壳末端最大压力,而机组转速最大上升率略有升高。为了进一步优化所得协联关闭规律,建立了以蜗壳末端最大压力和机组转速最大上升率为控制指标的导叶关闭规律非线性优化模型,基于确定的桨叶开启动作方式,采用模拟退火智能算法优化导叶两段折线关闭规律,得到了能够满足调节保证计算要求的水轮机导叶桨叶协联关闭规律,且各指标的安全裕量分配较为合理。相关结论可为轴流转桨式水轮机的关闭规律选取和优化提供参考。

Reasonable closing law of the turbine is extremely important to the control of the hydraulic transient guarantee values in hydropower stations.Because of the regulation of both blades and guide vanes,the selection and optimization of the closing law of the Kaplan turbine is complex.A new joint movement mode of blades and guide vanes is proposed for Kaplan turbines through an analysis of the turbine runaway curves.That is,the blades quickly open as the guide vane quickly close in load rejection transient process.According to the numerical simulation results of an engineering example,the maximum pressure at the volute end is greatly reduced by adopting the closing law,while the maximum unit speed increases slightly,which verifies the effectiveness of the new closing law.Based on the determined blades opening mode,the nonlinear optimization model and simulated annealing algorithm are used to optimize the two-stage closing law of the guide vanes.The closing law that meets the regulating guarantee requirements is obtained.The conclusion provides reference for selecting the closing law of Kaplan turbines.