基于电网频率控制的水电站调压室设置条件研究

Surge tank is one of the important hydropower station buildings, it's main setting purpose is to reduce the flow inertial of penstock,in order to meet the regulation guarantee requirements and improve the dynamic response ability of hydropower station governing system to meet the grid frequency control requirements. At present, the researches about the setting conditon of surge tank mainly focus on the regulation guarantee requirements and do not take the grid frequency control requirements into consideration. In this project, starting with the grid frequency control requirements for hydropower station, the setting condition of surge tank will be deeply studied by theoretical analysis and numerical simulation. The main research contents are as follows: Clarify the grid frequency control requirements for the hydro generator units governing system according to the characteristics of modern power system; Estabilsh the nonlinear mathematical model of frequency control of parallel running hydro generator units, according to the role and realization mode of hydro generator units in the grid frequency control; Research on the influence factors of dynamic quality of hydro generator units governing system, and clarify the influence mechanism; Establish the relationship between the dynamic quality of hydro generator units governing system and the setting condition of surge tank, Derive the setting condition of surge tank meeting the grid frequency control requirements, perfect the design theory of surge tank.

调压室的主要作用是减小压力管道的水流惯性，满足调节保证的要求，同时提高水电站调节系统的动态响应能力以满足电网频率控制的要求。目前我国调压室设计中未考虑电网频率控制对水电机组的要求，不仅给水轮机调节带来了极大困难，而且危害到整个电网的稳定及供电质量。本项目拟从电网频率控制对水电站的要求入手，采用理论分析与数值仿真相结合的方法，对调压室设置条件进行深入研究。主要研究内容为：根据现代电力系统的特点，明确电网频率控制对水电机组调节系统动态特性的要求，建立并列运行水电机组参与电网频率控制的非线性数学模型，并基于水电站实际运行数据对数学模型进行修正；利用数值计算研究水电机组参与电网频率控制的动态性能，找出主要影响因素，阐明影响机理；在此基础上研究动态品质与调压室设置条件之间的关系，利用非线性数学分析方法得出满足电网频率控制要求的水电站调压室设置条件，完善水电站调压室设计理论。

本项目基于电网频率控制对水轮机调节系统并网运行的要求，对调压室设置条件进行了深入的研究。明确了电网频率控制对水电机组动态响应过程的要求，为调压室设置条件的研究提供了衡量标准；建立了并列运行水电机组参与电网频率控制的非线性数学模型，并开发了相应的数值计算软件；通过数值仿真，分析了水电机组分别在孤网及并大网方式下的频率调节动态响应过程，研究了引水系统水流惯性、机组容量占电网比重、水轮机特性等因素对调节品质的影响，并找出了影响水电机组调节品质的最不利工况；从理论上分析了水电机组频率控制动态响应过程，并基于电网频率控制的要求从理论上得出了水电机组调压室的设置条件，完善了水电站调压室设计理论，极大推动了我国水电站调压室设计水平的进步。