构网型SVG改善系统电压跌落的空间分布特性与影响因素分析

Spatial Distribution Characteristics and Analysis of Influencing Factors for Voltage Sag Mitigation by Grid-Forming SVG

中文关键词:电压跌落  构网型静止无功发生器  阻抗矩阵修正模型  空间分布特性  配置容量

keywords:voltage sag  grid-forming SVG  impedance matrix correction model  spatial distribution characteristics  configured capacity

中文摘要:高比例新能源系统电压支撑能力下降，短路故障可能导致大范围新能源机组进入低电压穿越。针对这一问题，首先，构建了计及构网型静止无功发生器（static var generator，SVG）接入的节点阻抗矩阵修正模型，提出了电压跌落改善量的计算方法；其次，引入节点电气距离指标，建立电压跌落改善函数，定量分析了构网型SVG电压跌落改善效果的空间分布特性；再次，基于电压跌落改善函数分析了构网型SVG配置容量、配置节点自阻抗等因素对电压跌落改善效果的影响；最后，在改进的IEEE 39节点系统中验证了电压跌落改善空间分布特性与影响因素结论的正确性。结果表明：构网型SVG电压跌落改善的空间分布特性与配置点和故障点位置有关；此外，在自阻抗较高的节点配置构网型SVG或增大构网型SVG配置容量，可提升其电压跌落改善效果。

Abstract:To address the reduced voltage support capability in high-proportion renewable energy systems and solve the problem that short-circuit faults may cause large-scale renewable energy units to enter low-voltage ride-through，this paper conducts in-depth research. Firstly，a modified nodal impedance matrix model considering the integration of grid-forming static var generator （SVG） is constructed，and a calculation method for voltage sag improvement margin is proposed. Secondly，the index of nodal electrical distance is introduced to establish a voltage sag improvement function，which is used to quantitatively analyze the spatial distribution characteristics of voltage sag mitigation effect by grid-forming SVG. Furthermore，based on the voltage sag improvement function，the impacts of factors such as the configured capacity of grid-forming SVG and the self-impedance of configurated nodes on the voltage sag mitigation effect are analyzed. Finally，the correctness of the conclusions about the spatial distribution characteristics and influencing factors of voltage sag mitigation is verified in the modified IEEE 39-bus system. The results indicate that the spatial distribution characteristics of voltage sag mitigation by grid-forming SVG are related to the locations of both the configured point and the fault point； in addition，configuration of grid-forming SVG at nodes with higher self-impedance or increasing the configured capacity of grid-forming SVG is conducive to enhancing its voltage sag mitigation effect.