基于超长引水隧洞水电站巨大水流惯性的平压措施与机组运行控制策略的研究

For hydropower station with long-distance diversion tunnel, the extremely large flow inertia leads to the prominent contradictions between regulation parameters and control standard, stability and regulation quality. These two contradictions would bring great difficulties to the design for the measures of decreasing pressure and the security and stability of unit operation, restrict the hydropower development in Daguaiwan area. According to the above two contradictions, the study on the measures of decreasing pressure (the hydraulic design of surge chamber suitable for the extremely large flow inertia) and regulation guarantee, and the stability and regulation quality control of unit operation for hydropower station with long-distance diversion tunnel should be conducted on the basis of non-linear superposition mechanism of water hammer wave and surge in surge chamber, and the simplification solution of high order linear homogeneous differential equation with constant coefficients. This study is carried on from three aspects of theoretical analysis, numerical simulation and control strategy. The research purpose is: revealing non-linear superposition mechanism of water hammer wave and one or more surge in upper surge chamber; establishing the control strategy of stability and regulation quality of hydraulic and governor system based on frequency regulation mode, power regulation mode and servomotor stroke regulation mode; putting forward setting conditions of surge chamber on the base of regulation parameters, operation stability and regulation quality that considering wave superposition; making a hydraulic design criteria of multiple surge chamber system in transient process. The research results would lay the foundation of applied research and provide the support of key science and technology for the hydropower development in Daguaiwan area and the design and operation for other hydropower stations with long-distance diversion tunnel.

超长引水隧洞水电站水流惯性巨大，导致调保参数与控制标准之间、稳定性与调节品质之间矛盾十分突出，给此类水电站平压措施的设计和机组安全稳定运行带来了极大的困难，制约着雅鲁藏布江大拐弯水电开发的进展。本项目拟针对上述两个矛盾，以水击波与调压室涌波的非线性叠加机理和高阶线性常系数齐次微分方程的简化解法为基础，从理论分析、数值模拟和控制策略三个层面开展超长引水隧洞水电站的平压措施（即适合于巨大水流惯性的调压室水力设计）与调节保证、机组运行稳定性与调节品质控制的研究。力争揭示水击波与单个或多个上游调压室涌波的非线性叠加机理，建立基于水轮机频率功率开度三种调节模式的系统稳定性及调节品质控制策略，提出考虑波动叠加的基于调保参数、机组运行稳定性及调节品质的调压室设置条件，制定上游多调压室复杂平压系统的水力设计准则。为大拐弯水电开发、以及其他超长引水隧洞水电站设计运行奠定应用研究的基础和关键科学技术的支撑。

超长引水隧洞水电站是水电能源开发的一种重要的型式，在现阶段及未来时段的水电开发中将一直是极具竞争性的电站类型。但由于其引水隧洞水流惯性巨大，给平压设施的设置及机组运行的控制带来了巨大的挑战。本项目围绕平压设施的设置与设计、机组安全稳定运行与控制两个方面，开展了超长引水隧洞水电站调压室水力设计、设特殊型式/特殊组合平压设施超长引水隧洞水电站过渡过程特性、组合工况下超长引水隧洞水电站调压室涌浪的最不利设计与最有利运行、调压室通气洞过渡过程中的风速模拟、超长引水隧洞水电站调压室与电网联合作用下的水轮机调节系统暂态特性、基于水轮机调节模式的系统调节品质及调压室稳定断面和平压设施作用下的水轮机调节系统暂态过程控制研究等方面的研究，提出了超长引水隧洞水电站调压室水力设计方法、揭示了复杂型式/组合平压设施对超长引水隧洞水电站的适用性、建立了组合工况下超长引水隧洞水电站调压室涌浪的最不利设计与最有利运行设计理论、形成了调压室通气洞过渡过程中的风速模拟技术、揭示了超长引水隧洞水电站调压室与电网联合作用机理、发展了基于水轮机调节模式的系统调节品质及调压室稳定断面理论体系、提出了完整的平压设施作用下的水轮机调节系统暂态过程控制技术。项目研究取得的诸如调压室临界稳定断面、超长引水隧洞调压室水力设计、组合工况下调压室涌浪的最不利设计与最有利运行等新概念、新方法和新思路已经作为新的设计理念被应用到工程设计的实践中，提升了工程设计水平、增加了工程设计的安全性与可靠性，为超长引水隧洞水电站的建设运行提供了系统的理论基础和应用指导。