一种改良的主动频率偏移孤岛检测方法

An Islanding Detection Method of Improved Active Frequency Drift

摘要:

分布式发电系统中的孤岛检测问题是目前研究的难点，特别是传统主动频率偏移法在逆变器输出功率与负载功率平衡或者不平衡程度较小时，较难检测出孤岛并且输出电流存在较大的谐波含量。针对这个问题，在光伏并网发电系统中提出了一种改良的主动频率偏移孤岛检测方法。该方法把主动频率偏移与卡尔曼滤波的谐波估计相结合组成判断是否发生孤岛的依据。在Matlab/Simulink下进行系统仿真，验证了该方法有效地减少了传统主动频率偏移法存在的检测盲区，也明显地降低了逆变器输出电流的谐波含量。

Abstract:

Island detection in the distributed power generation system is the difficulty of the current research. In particular, the traditional active frequency drift method is difficult to detect the islanding phenomenon and the current-output?has large harmonics contents when the inverter output power and load active power balance or a small degree of imbalance. For this problem, an improved active frequency drift island detection method is proposed in PV grid-connected power generation system. This method combines the active frequency drift and Kalman filtering of harmonic estimation method to determine whether or not it is produced the islanding phenomenon. At the same time, by reducing the frequency detection threshold, the traditional active frequency drift method reduces effectively non-detection zone, and reduces significantly the inverter output current harmonic contents. Simulation of Matlab/Simulink is carried out to verify the effectiveness of the proposed method.