水电机组超低频振荡小信号模型及影响因素分析  

Small-signal Model and Influencing Factors Analysis of Ultra-low Frequency Oscillation in Hydropower Unit

作　　者：王鹏[1] 刘天琪[1] 王顺亮 江琴[1] 仰玲芳 李保宏[1] WANG Peng;LIU Tianqi;WANG Shunliang;JIANG Qin;YANG Lingfang;LI Baohong(School of Electrical Engineering,Sichuan University,Chengdu 610065,Sichuan Province,China)

机构地区：[1]四川大学电气工程学院,四川省成都市610065

出　　处：《中国电机工程学报》2020年第18期5942-5954,共13页Proceedings of the CSEE

摘　　要：近年来,水电机组占比较大的电网多次发生振荡频率低于0.1Hz的超低频振荡事件,严重影响了系统的安全稳定运行。为明晰超低频振荡发生场景,首先,建立单机无穷大系统和单机带负荷系统模型,分别推导了两系统在考虑与不考虑励磁和电力系统稳定器(power system stabilizer,PSS)时的线性化状态空间模型,求解出不同的振荡模式。然后,基于振荡幅值计算,提出用振荡能量级理论来评估系统主导振荡模式的方法,解释了受端为非无穷大系统时更容易产生超低频振荡的原因。其次,根据建立的单机带负荷系统状态空间模型,从机理上分析了励磁调节和PSS对系统超低频振荡的影响并确定了影响超低频振荡的因素,得出适当增加调速器比例与积分环节增益比值可以有效抑制超低频振荡。最后仿真验证了调速器、励磁系统和PSS对超低频振荡的影响,同时在单机无穷大系统中验证所提评估主导振荡模式方法的正确性。In recent years, ultra-low frequency oscillations with the frequency below 0.1 Hz have occurred many times in power grids where hydropower units account for a large proportion, which seriously affected the safety and stability of the system. In order to clarify the scene of ultra-low frequency oscillation, a single machine infinite bus system and a single machine load system models were first established in this paper, and the linearized state space models of the two systems were deduced when considering and not considering the excitation and power system stabilizer(PSS). Different oscillation modes were solved based on the state space models. Then based on the calculation of oscillation amplitude, the method of estimating the dominant oscillation mode of the system by the theory of oscillation energy level was proposed, which explains the reason why the ultra-low frequency oscillation is more likely to occur when the receiving end is a non-infinite system. Secondly, according to the established state space model of single-machine load system, the influence of excitation regulation and PSS on the ultra-low frequency oscillation of the system was analyzed. The factors affecting the ultra-low frequency oscillation were determined, and the proportion and integral of the governor were appropriately increased can effectively suppress the ultra-low frequency oscillation. Finally, the simulation verifies the influence of governor, excitation system and PSS on ultra-low frequency oscillation, and verifies the correctness of the proposed method for evaluating dominant oscillation mode in single machine infinite bus system.

关 键 词：超低频振荡 状态空间模型 振荡能量级 励磁调节 电力系统稳定器 

分 类 号：TM612[电气工程—电力系统及自动化]