低谐波畸变的快速主动移频式孤岛检测方法  

Fast Active Frequency Drift Islanding Detection Method with Lower Total Harmonic Distortion

作　　者：邹培源 黄纯[1,2] 白振宇 石雁祥 王永红[2] 

机构地区：[1]湖南大学电气与信息工程学院,长沙410082 [2]伊犁师范学院电子与信息工程学院,伊宁835000

出　　处：《电力系统及其自动化学报》2018年第1期58-63,共6页Proceedings of the CSU-EPSA

基　　金：国家自然科学基金资助项目(51677060)

摘　　要：主动频率偏移法是光伏发电并网系统较常用的孤岛检测方法。通过增大扰动强度可以加快检测出孤岛,但同时增加了谐波畸变量,扰动强度可由截断系数来表征,因此选取合适的截断系数是一研究难点。针对现有算法不能兼顾电能质量和孤岛检测速度的问题,提出一种新的截断系数控制策略,并根据公共耦合点电压频率的偏移量和偏移变化率对正反馈系数进行动态模糊优化。建立孤岛检测的Simulink仿真模型,仿真分析表明该方法在电网正常供电运行时截断系数较小,有效降低逆变器输出电流的谐波畸变量;电网断电后能快速、准确检测出孤岛,不存在检测盲区。Active frequency drift （AFD） method is commonly used in islanding detection for grid-connected photovoltaic generation system. The increase of disturbance intensity characterized by chopping fraction can speed up the detection of islanding, however, it also magnifies the total harmonic distortion （THD）. Therefore, it is a hard work to select a suit- able chopping fraction. With the consideration that the existing algorithms cannot keep a balance between power quality and islanding detection speed, a new control strategy of chopping fraction is proposed in this paper. Moreover, according to frequency drift and its variation rate of the point of common coupling （PCC） voltage, dynamic fuzzy optimization is performed on the positive feedback coefficient. A simulation model of islanding detection is established, and simulation results show that the proposed method can reduce the THD of inverter current by minimizing the chopping fraction under normal condition, and detect islanding quickly and accurately after power off without non-detection zone（NDZ）.

关 键 词：光伏发电 孤岛检测 主动频率偏移法 模糊优化 截断系数 

分 类 号：TM615[电气工程—电力系统及自动化]