计及负荷频率特性的风水电系统频率特性分析

随着新能源占比的升高，在水电资源丰富的云南电网中，依赖传统机组一次调频已不能满足云南异步联网系统频率稳定性的要求。针对大型水电水锤效应引起的功率反调问题，提出了一种计及负荷频率特性的风储联合调频控制策略。首先建立了传统电源(水轮机)、双馈风机、储能系统、综合负荷的频域模型传递函数；然后采用直流潮流法简化电网，得到了负荷扰动下风储节点频率响应解析式。在电力系统仿真程序PSD-BPA中搭建含风储、水机、负荷的四机系统。通过对解析式的理论分析和四机系统的仿真验证，分析了静态负荷模型比例、频率特征参数以及储能占比等因素对系统频率的影响。结果表明，计及负荷频率特性的风储联合调频能有效减小系统频率偏差。

Analysis of Frequency Characteristics of Wind-Hydro Power System Considering Load Frequency Characteristics

With the increase of the proportion of new energy, in the Yunnan power grid with abundant hydropower resources, relying on the primary frequency modulation of traditional units can no longer meet the requirements of frequency stability of Yunnan asynchronous networking system. For the power reverse adjustment caused by the water hammer effect of large hydropower, a wind-storage combined frequency modulation control strategy considering load frequency characteristics is proposed. Firstly, the frequency domain model transfer function of traditional power (turbine), doubly-fed wind turbine, energy storage system and comprehensive load is established. Then, the DC power flow method is used to simplify the electric network, and the analytical formula of frequency response of wind-storage node under load disturbance is obtained. The four\|machines system with wind\|stroage, water turbine and lood is built in the electromechanical transient simulation sofware PSD\|BPA. Through the theoretical analysis of the analytical formula and the simulation verification of the four-machine system, the influence of the proportion of static load model and frequency characteristic parameters and the proportion of energy storage on the system frequency is analyzed. The results show that the wind-storage combined frequency modulation considering the load frequency characteristics can effectively reduce the system frequency deviation.