面向超低频振荡的水电调速器与SVC附加频率控制参数联合优化

Joint Optimization of Hydroelectric Governor and SVC with Additional Frequency Control Parameters for Ultra-low Frequency Oscillation

摘要:

互联电网超低频振荡抑制对系统安全稳定运行至关重要，现有研究仅考虑水电调试器PI控制参数优化的措施，可能导致水电调频能力降低。随着电网中静止无功补偿器(SVC)数量的显著增长，通过SVC附加频率控制为超低频振荡抑制提供了新的思路,于是提出了一种SVC附加频率控制与水电调速器PI参数联合优化方法。首先,建立了包含水轮机和SVC的单机单负荷系统等值模型，分析SVC的附加频率控制原理，并分析所提模型对系统超低频振荡的抑制作用；在此基础上，以超低频振荡阻尼系数和水电机组一次调频性能为优化目标，通过优化设计控制器参数以提升系统整体的超低频振荡抑制能力；最后，在PSCAD/EMTDC平台上搭建了水电机组和SVC仿真模型，对所提方法进行有效性验证。仿真结果表明，该方法可有效提升高比例水电电网超低频振荡阻尼能力，同时提升水电机组调频能力。

Abstract:

Ultra-low frequency oscillation suppression of interconnected power grid is crucial for safe and stable grid operation. The existing studies only consider optimizing the PI control parameters of hydroelectric governer, which may reduce the hydroelectric frequency regulation capability. The significant growth of static var compensators (SVC) in power grid introduces a new idea for ultra-low frequency oscillation suppression. A method to jointly optimize SVC with additional frequency control and PI parameters of hydroelectric gover-nors is proposed. Firstly, an equivalent model of a single-machine single-load system is established, which contains a hydraulic turbine and SVC. The principle of SVC with additional frequency control and its suppression effect on ultra-low frequency oscillation of system are analyzed. On this basis, taking damping coefficient of ultra-low frequency oscillation and primary frequency regulation performance of hydropower units as optimization objectives, the controller parameters are optimally designed to improve the overall capability of ultra-low frequency oscillation suppression. Finally, a simulation model for the hydropower units and SVC is constructed on PSCAD/EMTDC platform, which verifies the effectiveness of the proposed method. The simulation results show that the proposed method can effectively improve the damping capacity of ultra-low frequency oscillations in power grid with high proportion of hydropower, and can also improve the frequency regulation capability of hydropower units.