摘要
由于无法辨析并网点(point of common coupling,PCC)电压跌落的本质原因,光伏电站低压穿越(low voltage ride through,LVRT)控制与现有的孤岛保护在同时满足动作条件时缺乏选择性,影响系统的安全稳定。为研究与光伏LVRT相互协调的孤岛检测方法,根据孤岛现象和电压暂态扰动现象发生时PCC谐波电压的差异,提出一种基于光伏并网点谐波电压突变的无功功率扰动孤岛检测方法。该方法在检测到PCC处的谐波电压突变后,经40 ms延时,对光伏逆变器输出的无功电流采用基于PCC频率变化量函数进行扰动,使PCC频率超出正常范围,实现孤岛检测功能。仿真结果表明:方法在保证与LVRT协调配合的前提下能在较短时间内完成对光伏电站孤岛状态的检测;此外在故障特征量较小的工况下方法依然可靠适用,消除了传统孤岛检测方法盲区的同时保证了孤岛检测的准确性。
Due to the inability to identify the essential causes of the voltage drop at the point of common coupling(PCC),it’s not sure how to choose the low voltage ride through(LVRT)control of photovoltaic power plants or the island protection when satisfying the operating conditions at the same time,which affects system security and stability.To study the islanding detection method coordinated with photovoltaic LVRT,a reactive power disturbance islanding detection method based on the harmonic voltage mutation at the PCC was proposed according to the difference of the harmonic voltage at the PCC between the phenomenon of islanding and the voltage transient disturbance.In this method,after a delay of 40 ms,the reactive current output by the photovoltaic inverter was perturbed by a function based on the PCC frequency variation when harmonic voltage mutation at the PCC is detected,so that the PCC frequency exceeds the normal range and realizes the island detection.The simulation results show that the method can detect the islanding state of photovoltaic power plants in a short time under the premise of ensuring the coordination with LVRT.In addition,the method is still reliable and applicable under the condition of small fault feature quantity,which eliminates the blind area of traditional islanding detection method and ensures accuracy of islanding detection.
作者
戴志辉
何静远
于礼瑞
张艺宏
吴桐
赵謇
DAI Zhi-hui;HE Jing-yuan;YU Li-rui;ZHANG Yi-hong;WU Tong;ZHAO Jian(Hebei Key Laboratory of Distributed Energy Storage and Microgrid,North China Electric Power University,Baoding 071003,China)
出处
《电机与控制学报》
EI
CSCD
北大核心
2023年第3期10-20,共11页
Electric Machines and Control
基金
国家自然科学基金(51877084)。
关键词
光伏电站
低压穿越
孤岛检测
电压暂态扰动
谐波电压
无功功率扰动法
无功电流
photovoltaic power plant
low voltage ride through
islanding detection
voltage transient disturbance
harmonic voltage
reactive power disturbance method
reactive current
