冲击式水电机组不同工况下孤网运行的稳定性分析

Stability Analysis of Pelton Hydropower Units Under Different Operating Conditions in Isolated Grid

我国西南建有大量的冲击式水电机组的水电站,这些水电站与电网联系薄弱,孤网运行稳定性问题突出。对此建立了冲击式水轮机的数学模型、完善了冲击式水电机组孤网分析模型,研究了孤网条件下冲击式水电机组的控制参数稳定域。首先,根据电站实际情况建立冲击式水轮机的非线性模型。其次,根据李雅普诺夫第一方法开展稳定性分析,在不同运行工况点对冲击式水轮机进行线性化,获得相关传递系数,代入孤网分析模型建立状态方程,根据临界稳定条件求出稳定域。最后,通过非线性模型仿真对分析结果进行验证。结果表明,喷针开度变化时对运行稳定域的影响较大,不能忽视;调速器参数整定时,需对所有运行工况进行分析,按最小稳定域工况进行参数优化。

There are a large number of hydropower stations with Pelton turbine in southwestern region,which have weak connections with the power grid and prominent stability issues in isolated grid operation.This article establishes a mathematical model of Pelton turbine,improves the analysis model for the isolated grid of Pelton turbine,and studies the stable range of control parameters for Pelton turbine in isolated grid.Firstly,a nonlinear model of the Pelton turbine is established based on the actual situation of the hydropower station.Secondly,stability analysis is conducted based on the Lyapunov first method.The state equation is established by linearizing the Pelton turbine at different operating conditions,calculating the relevant transfer coefficients,and substituting them into the isolated grid analysis model.The stability region is determined based on the critical stability conditions.Finally,the analysis results are validated through nonlinear model simulation.The results indicate that the changes in the opening of the spray needle have a significant impact on the operating stability region and cannot be ignored.When adjusting the parameters of the governor,it is necessary to analyze all operating conditions and optimize the parameters according to the minimum stable region conditions.