采用时频坐标变换的大规模交直流系统多模态仿真方法

Multi-domain Simulation Method for Large-scale AC/DC Systems Based on Time-Frequency Coordination Transform

为了准确地仿真大规模交直流系统的动态特性和各个元件之间的相互影响,亟需一种高精度、高效率的仿真方法。为此,文中提出了基于时频坐标变换的大规模交直流系统多模态仿真方法。在该方法中,直流系统采用时频变换模型进行建模并划分到频移子系统,可以在保证精度的前提下采用更大的步长进行仿真,使仿真效率明显改善。同时还对频移子系统与电磁子系统之间的接口模型,即多模态接口传输线模型进行了优化设计。该接口模型可同时反映动态过程的瞬时值波形和相量值波形。最后,采用国内某实际含有四端柔性直流系统的大规模交直流系统作为案例进行测试,证实了所提方法的有效性。

In order to accurately simulate the dynamics of large-scale AC/DC systems and interactions between individual components, a simulation method with high precision and efficiency is highly required. A multi-domain simulation method for largescale AC/DC systems based on time-frequency coordination transform is proposed. In this method, DC systems are partitioned into the phasor-shift sub-systems, which are presented by their phasor-shift models based on the time-frequency coordination transform. This method can adopt large time-step to improve the efficiency while the accuracy is guaranteed. Further, a multidomain interface model between phasor-shift sub-systems and electromagnetic sub-systems,which is also called interface transmission line model,is optimally designed. The interface model can reflect both instantaneous and wide-band phasor waveforms simultaneously. Finally, an actual AC/DC system integrating four-terminal flexible DC system in China has validated the effectiveness of the proposed method.