构网型柔性直流系统动态特性分析

Analysis on Dynamic Characteristics of Grid-Forming VSC-HVDC Transmission System

随着新能源渗透率的不断增加,传统同步发电机装机容量下降,使得电网的惯性效应和阻尼能力逐渐降低。为了解决上述问题,以构网型柔性直流系统为研究对象,通过电气转矩分析法研究了影响构网型柔性直流系统惯量水平和阻尼特性的主要因素。研究结果表明:构网型柔性直流系统的虚拟同步发电机控制系数和下垂系数可以等效地调节系统的惯性和阻尼特性。仿真结果验证了研究结论的正确性和有效性,结论将有助于设计有效的构网型柔性直流系统控制策略,以辅助提升交直流混联大电网的惯量水平与阻尼能力。

With the increasing penetration rate of new energy resources,the installed capacity of traditional synchronous generators decreases,which makes the inertia effect and damping capacity of power grid gradually decrease.In order to solve the above problem,the grid-forming voltage source converter-based high-voltage direct current(VSC-HVDC)transmission system is taken as the research object,and the main factors affecting the inertia level and damping characteristics of grid-forming VSC-HVDC transmission system are studied by using the electrical torque analysis method.The research results show that the control coefficient and droop-coefficient of the virtual synchronous generator can adjust the inertia and damping characteristics of the grid-forming VSC-HVDC system.The simulation results verify the correctness and validity of the research conclusions,which will be helpful to design an effective control strategy for the grid-forming VSC-HVDC system to help improve the inertia level and damping capacity of AC-DC hybrid great power grid.