风电场引发火电机组次同步振荡的机理及影响因素研究

风能资源的大规模开发利用是实现能源转型升级的必然途径。然而,大规模风电场并网稳定性问题逐渐凸显,实际系统中出现了风电场引发火电机组次同步振荡现象。建立了风火联合外送系统模型,应用谐波响应法和复转矩系数法分析了风电场引发火电机组次同步振荡的机理。在此基础上,分析了火电机组轴系扭振特性、风电场容量、风速、风机转子侧变频器内环增益系数以及风电场至火电机组的电气距离对次同步振荡的影响。结果表明,轴系扭振模态可观测度越高、风电场容量越大、风机风速越高、风机转子侧变频器内环增益系数越大以及风电场与火电机组的电气距离越远,火电机组次同步振荡越剧烈。通过IEEE第一基准模型和IEEE39节点系统的时域仿真验证了上述结论的有效性。

Study on the mechanism and influencing factors of subsynchronous oscillations induced by wind farms in a fossil fuel power plant

Large-scale development and utilization of wind energy is a significant way to achieve energy transformation and upgrading. However, the stability of large-scale wind farms connected to the grid has become an increasing problem. In an actual system, wind farms cause Sub-Synchronous Oscillation (SSO) of thermal power units. This paper establishes a model of a wind farm and thermal power unit combined delivery system. It applies the harmonic response method and the complex torque coefficient method to analyze the mechanism of SSO induced by wind farms in a fossil fuel power plant. Influencing factors on SSO such as the torsional vibration characteristics of the shafts, the capacity of the wind farm, the wind speed, the gain coefficient of inner current loop of RSC and the electrical distance from the wind farm to the thermal power unit are analyzed. The results show that the higher the observability of the torsional vibration mode of the shaft system, the larger the wind farm capacity, the higher the fan speed, the larger the gain coefficient of inner current loop of RSC and the farther the electric distance between the wind farm and the thermal power unit, the more severe SSO of the thermal power unit. The validity of the above conclusion is verified by time domain simulation of the first IEEE standard model and the IEEE39-bus system. This work is supported by the National Natural Science Foundation of China (No. 51677066).