Comparative analysis of stability limitations in weak grid-connected synchronous generator, VSC, and DFIG systems considering the power flow control dynamics
Comparative analysis of stability limitations in weak grid-connected synchronous generator, VSC, and DFIG systems considering the power flow control dynamics
复制标题
考虑潮流控制动力学的弱并网同步发电机、VSC 和 DFIG 系统稳定性限制的比较分析
DOI：
10.1049/iet-rpg.2018.5001
复制
发表时间：
2019
影响因子：
2.6
通讯作者：
Hu Jiabing
中科院分区：
文献类型：
--
作者：
Wang Dong;Hou Yunhe;Hu Jiabing
在传统电力系统中，同步发电机（SG）在弱电网条件下会遇到稳定性问题。最近，在逆变器接口系统中也观察到类似的问题，包括基于全电压源换流器（VSC）的高压直流和部分VSC接口的双馈感应发电机（DFIG）系统，但实际上这些不稳定性的根本原因尚未完全了解。本研究旨在为这些不稳定问题的根源提供可能的统一解释。借鉴SG不稳定机制的经验，对于VSC和DFIG系统，主要关注外部潮流控制的动力学，首先并行提出降阶模型。然后，围绕这些系统的有功功率控制环路进行分析，发现随着电网强度的减小，开环零点将向右半平面移动。右半平面零点（RHPZ）出现的边界是通过分析得出的。此外，还说明了关于这些确定的 RHPZ 局限性的一般解释，包括对稳定性的不利相位滞后效应和对稳定性边界的吸引效应。此外，还提供了这些系统中 RHPZ 起源的统一解释。进行时域仿真以验证分析。
In the conventional power systems, the synchronous generators (SGs) are known to suffer stability issues under weak grid conditions. Recently, similar problems are observed in the inverter interfaced systems, including the full voltage source converter (VSC)‐based high‐voltage DC, and partial VSC interfaced doubly fed induction generator (DFIG) systems, but the root causes of these instabilities in reality are not completely understood yet. This study aims to provide a possible unified explanation for the origin of these instability issues. With the experiences of SG's instability mechanism, for the VSC and DFIG systems, the dynamics of outer power flow controls are mainly focused, and the reduced‐order models are parallelly presented first. Then, centralised around the active power control loops of these systems for analysis, it is found that an open‐loop zero will move to the right half plane with grid strength decrease. The borders for the occurrence of right‐half‐plane zeros (RHPZs) are analytically derived. Further, a general interpretation regarding these identified RHPZs’ limitations, including the adverse phase lag effect on stability and the attraction effect on the stability boundary, is illustrated. In addition, a uniform explanation for the origin of the RHPZs in these systems is also provided. Time‐domain simulations are conducted to validate the analysis.