虚拟惯性时间常数对互联电网小干扰稳定影响研究

传统同步发电机的惯性时间常数是不变的物理参数,虚拟同步发电机的推广与应用使得系统惯性时间常数具有可变性和可调性,继而有可能影响互联系统的小干扰稳定性。论文以VSC-HVDC为研究对象,对其进行虚拟同步发电机控制建模,然后基于特征分析法,对等值联网系统求解低频振荡衰减因子的解析表达式,分析了不同场景下惯性时间常数对小干扰稳定水平的影响程度,发现当惯性时间常数与阻尼系数在同一个数量级时对小干扰稳定有较大影响。最后在两区四机经典模型中验证了结论,对于虚拟同步发电机参数整定和研究互联系统的小干扰稳定性分析及控制具有一定的参考价值。

Research of Influence of Virtual Inertia Time Constant on Interconnected Power System Small Disturbance Stability

In the traditional power system, the inertia time constant of a synchronous generator is an invariant physical parameter. However, with the application and popularization of the virtual synchronous generators, the inertia time constant of the system becomes variable and adjustable, which may affect the small disturbance stability of the interconnected system. VSC-HVDC is taken as the research object and the virtual synchronous generator control is built on it. Then, based on the eigenvalue analysis method, the analytic expression of the low-frequency oscillation attenuation factor for the equivalent networking system is solved, and the degree of influence of the inertial time constant on the stability level of small disturbance is analyzed. In the proposed method, the inertia time constant has a great influence on the small disturbance stability when being in the same order of magnitude with damping coefficient. Finally, the influence of the inertia time constant on the regional low frequency oscillation mode is verified in the classical model of 2-area 4-generator, which has certain reference value for the analysis and control of the regional small disturbance stability of the interconnected power system and the virtual synchronous generator parameter setting.