构网型储能变换器在新能源接入场景下 并网稳定性分析及提升策略

Grid-connected Stability Analysis and Improvement Strategy for Grid-forming Energy Storage System in New Energy Access Scene

构网型储能变换器因具备解决新能源消纳、提升系统转动惯量等能力,被视作构建新型电力系统的关键设备。文中围绕构网型储能接入对新能源场站并网稳定性的影响开展研究工作。首先建立构网型与跟网型储能变换器特征阻抗模型,分析构网型与跟网型储能接入对于新能源场站并网稳定性的影响,研究结果表明,储能以构网形式接入更有利于提升新能源场站并网稳定性。在此基础上,探究构网型储能变换器对于新能源场站阻抗特性的影响规律,针对其弱主导频段中新能源机组负阻特性凸显问题,提出一种提升构网型储能变换器阻抗主导能力的自主阻抗适配控制,在系统谐振频率的实时检测基础之上,实现不同电网工况下自适应阻抗适配,有效提升了新能源场站并网系统稳定性。最后,通过RT-LAB控制硬件在环完成相关频率特性及其自主阻抗适配控制方法有效性的实验验证。

The grid-forming(GFM)energy storage system(ESS)is regarded as the key equipment for building a new-type power system because of its ability to solve new energy consumption and improve the rotational inertia of the system.This paper focuses on the influence of GFM-ESS access on the grid-connected stability of new energy power stations.First,the modeling and frequency characteristics of GFM-ESS and grid-following energy storage system(GFL-ESS)are presented,and the influence of GFM-ESS and GFL-ESS on the grid-connected system stability is analyzed.The results show that the GFM-ESS is more conducive to improving the grid-connected system stability.On this basis,the influence of the GFM-ESS on the impedance characteristics of the new energy power station is explored.In view of the prominent negative resistance characteristics of the new energy unit in the weak dominant frequency band,an autonomous impedance adaptive control is proposed to improve the impedance dominant ability of the GFM-ESS.Based on the real-time detection of the system resonance frequency,the autonomous impedance adaptation with different grid conditions is realized,the GFM-ESS can effectively improve the grid-connected system stability.Finally,the experimental verification of the relevant frequency characteristics and the effectiveness of the autonomous impedance adaptation control method are depicted by the hardware-in-the-loop platform.