Ji Yuxi, He Wei, Cheng Shijie, Kurths Jürgen, Zhan Meng
The State Key Laboratory of Advanced Electromagnetic Engineering and Technology, School of Electrical and Electronic Engineering, Huazhong University of Science and Technology, Wuhan, 430074, China.
Potsdam Institute for Climate Impact Research, Telegraphenberg, Potsdam, D-14415, Germany.
Sci Rep. 2020 Jun 19;10(1):9946. doi: 10.1038/s41598-020-66635-0.
Power flow studies in traditional power systems aim to uncover the stationary relationship between voltage amplitude and phase and active and reactive powers; they are important for both stationary and dynamic power system analysis. With the increasing penetration of large-scale power electronics devices including renewable generations interfaced with converters, the power systems become gradually power-electronics-dominant and correspondingly their dynamical behavior changes substantially. Due to the fast dynamics of converters, such as AC current controller, the quasi-stationary state approximation, which has been widely used in power systems, is no longer appropriate and should be reexamined. In this paper, for a better description of network characteristics, we develop a novel concept of dynamic power flow and uncover an explicit dynamic relation between the instantaneous powers and the voltage vectors. This mathematical relation has been well verified by simulations on transient analysis of a small power-electronics-based power system, and a small-signal frequency-domain stability analysis of a voltage source converter connected to an infinitely strong bus. These results demonstrate the applicability of the proposed method and shed an improved light on our understanding of power-electronics-dominant power systems, whose dynamical nature remains obscure.
传统电力系统中的潮流研究旨在揭示电压幅值与相位以及有功和无功功率之间的静态关系；它们对于电力系统的静态和动态分析都很重要。随着包括与变流器相连的可再生能源发电在内的大规模电力电子设备的渗透率不断提高，电力系统逐渐由电力电子主导，相应地其动态行为也发生了显著变化。由于变流器（如交流电流控制器）的快速动态特性，电力系统中广泛使用的准静态状态近似不再适用，应重新审视。在本文中，为了更好地描述网络特性，我们提出了一种新颖的动态潮流概念，并揭示了瞬时功率与电压矢量之间的明确动态关系。通过对基于小型电力电子的电力系统的暂态分析以及连接到无穷大母线的电压源变流器的小信号频域稳定性分析进行仿真，很好地验证了这种数学关系。这些结果证明了所提方法的适用性，并为我们理解动态本质仍不明确的电力电子主导型电力系统提供了更深入的见解。
