摘要
虚拟同步发电机(virtual synchronous generator,VSG)技术因其使逆变器能够模仿同步发电机的运行机制,不仅使分布式电源接入电网呈现友好特性,而且增强了电网的稳定性,从而得到了广泛的研究。然而传统VSG控制由于难以提供可控的无功功率而不具备低电压穿越(low voltage ride through,LVRT)能力,当远端发生故障导致电压下降时,难以提供无功支撑,容易出现电流过流等问题。因此,针对上述问题采用一种计及模式切换的低电压穿越控制方法。分析了VSG基本原理,针对换流器采用VSG控制,在传统LVRT方法的基础上,设计了VSG低电压穿越控制的方法。针对电网故障工况下换流器的LVRT问题,结合传统LVRT控制方案,采用一种模式切换控制策略,以柔性电力电子开关(SOP)为研究对象,通过仿真结果进行对比。仿真结果验证了VSG控制结合LVRT控制可以抬升电压,在表现出传统发电机动态特性的同时,还可以提升供电可靠性,同时该控制策略可以在表现出传统发电机动态特性的同时,加入低穿特性,可提升供电可靠性,帮助换流器度过瞬时暂态过程,同时发出无功功率支撑电压恢复,同时满足低电压穿越期间的电网需求。
The Virtual Synchronous Generator(VSG)technology has been widely studied because it enables the inverter to imitate the operation mechanism of synchronous generator,which not only makes the distributed generation access to the power grid friendly,but also enhances the stability of the power grid. However,the traditional VSG control does not have the ability of low voltage ride through(LVRT)because it is difficult to provide controllable reactive power. When the voltage drops due to a remote fault,it is difficult to provide reactive power support and is prone to current overcurrent. To this end,this paper proposes a low voltage ride through control method that takes into account mode switching.First,based on the establishment of the VSG control mathematical model,the VSG control is adopted for the converter,combined with the traditional LVRT control method,the VSG low voltage ride through control method is designed,so that the VSG provides reactive power support during the voltage drop. This control strategy can show the dynamic characteristics of traditional generators while adding low-pass characteristics to improve power supply reliability,help the converter to survive the transient process,and at the same time meet the grid requirements during the low voltage ride-through period. With Flexible Power Electronic Switch(SOP)as the research object,a simulation model is built using PSCAD/EMTDC. The simulation results verify the correctness and effectiveness of the proposed method.
作者
张蝶
李雨龙
袁旭峰
张腊华
熊炜
班国邦
ZHANG Die;LI Yulong;YUAN Xufeng;ZHANG Lahua;XIONG Wei;BAN Guobang(School of Electrical Engineering,Guizhou University,Guiyang 550025,Guizhou,China;Guizhou Electric Power Research Institute,Guiyang 550002,Guizhou,China)
出处
《电网与清洁能源》
北大核心
2022年第9期45-54,64,共11页
Power System and Clean Energy
基金
国家自然科学基金资助项目(51667007)
贵州省科学技术基金项目([2019]1128,[2018]5615)。
关键词
虚拟同步发电机
低电压穿越
无功支持
模式切换
virtual synchronous generator
low voltage ride through
reactive power support
mode switching
