并网逆变器的电磁暂态同步稳定问题

Electromagnetic transient synchronization stability with grid-connected inverters

新能源通过并网逆变器(grid-connected inverter,GCI)汇集正深刻地改变着现代电力系统的动态特性,由同步发电机主导的机电暂态稳定分析因未全面计及电磁暂态影响而面临失效。该文综述了一类大扰动使新能源发电机组故障穿越期间,GCI与主网失去同步,引发对应机组退出系统的电磁暂态同步稳定问题。首先介绍了GCI的电流源和电压源型控制结构,指出与同步发电机同步机理的异同;其次介绍了体现电力电子特征的关注要素和兼顾精度与速度的简化条件;进而介绍了面向该问题典型的建模-分析流程和稳定性提升策略;最后展望了面向未来电力系统暂态稳定的研究挑战。

The integration of new energy sources through grid-connected inverters(GCI)is changing the dynamic characteristics of modern power systems.Electromechanical transient stability analyses for systems dominated by synchronous generators are no longer comprehensive since they do not take the electromagnetic transients into account.This paper presents an overview of electromagnetic transient synchronous stability issues of GCI during fault ride-throughs of new energy generation units caused by large disturbances in which the GCI loses synchronization with the main system which causes the corresponding generator to go offline.This paper describes the GCI current source and voltage source control and the synchronization mechanism compared with that of the synchronous generator.This paper then introduces the key factors characterizing the power electronics and simplifications that give fast accurate results.Then,this paper introduces the typical modeling-analysis process and stability improvement strategies.Finally,further research challenges are identified to improve the power system stability.