机-电耦联条件下水力发电系统暂态分析

本文研究了水电站引水、水轮发电以及调节控制系统(水-机-电系统)的耦联建模及暂态分析方法。在水-机-电系统耦联框架下,首先基于耦合水击理论的4-方程模型,利用其结合部耦合机制,通过压力钢管与水轮机活动导叶的结合部耦合连接水轮机系统,导出了引水系统与水轮机系统的耦联模型。其次,将水轮机模型综合特性曲线转化成对应不同开度的插值特性曲线,结合一阶发电机模型和调速器控制方程,导出了水轮机系统与电力系统的耦联关系,从而建立了单机单管无调压井水力发电系统水-机-电耦联非线性模型及其求解方法,实现了具有不同物理属性的力学系统内部参数耦联的暂态分析。数值算例表明,提出的模型和计算方法能反映水力发电系统暂态过程与电力负荷扰动的动力学机制,可较好地响应来自电力系统的功率扰动,并有效预测暂态过程中各系统的参数变化规律。

Transient modeling of hydraulic electricity-generating system in water-machine-electricity coupling conditions

This paper is concerned with coupling modeling and analysis methodology of transients in interacting constitutions of water-conveying system,hydro-turbine electricity generating system,and speed-governing control system (referred as water-machine-electricity system) for a hydroelectric station. Firstly, under the interacting framework of the water-machine-electricity system, an analytical solution in frequency domain for 4-equation model in fluid-structure interaction was obtained, and the junction coupling of penstock with turbine wicket gates was applied to yield coupling model of the water-conveying and hydro-turbine electricity generating systems. Then, based on turbine model hill chart curves that are transferred into a set of interpolation curves with different openings of wicket gates, one-order model of electricity-generating machine and dynamical equation of speed-governor were used to express modeling of hydro-turbine electricity generating and electricity systems. So, a nonlinear coupling model of the water-machine-electricity system with a one-penstock and one-machine system without a surge tank was established,and a monolithic analysis method of the transients of the systems in coupling condition was proposed. The simulating results show that the modeling proposed is able to be well responsive to power perturbations from an electric system,and predictions of the dynamical parameters of the systems are completely fare well.