采用HHT-LES算法的交流微网电压暂降快速检测

Rapid detection of voltage sag in AC micro-grid using HHT-LES algorithm

微电网惯性小、容量小,微源或负载的波动极易造成交流馈线的电压暂降,影响系统的稳定性.提出一种融合希尔伯特-黄变换(HHT)和最小方差滤波(LES)算法的HHT-LES电压暂降快速检测方法.利用短时HHT自适应采样算法实现可变窗口采样,并结合改进型LES算法实现对电压暂降的时间、幅值和相位跳变时刻的检测.仿真模型表明,与d-q变换或HHT方法相比,系统响应速度和检测精度都可提高20%.基于上述方法研制的新型电能质量综合控制器(NPQC)样机,在微网电压暂降实验平台进行验证;分析该算法对响应时间与检测精度的影响.试验结果表明,该算法可在5.2ms内实现对微电网电压暂降的快速检测.

In micro-grid of small inertia and small capacity,micro-source or load fluctuations can easily cause the AC feeder voltage drop,affecting the system's stability.Aiming at this problem,a HHT-LES voltage sag rapid detection method was proposed with integration of Hilbert-Huang transform(HHT)and least error squares(LES)algorithm.The variable window sampling was realized by the short time HHT adaptive sampling algorithm;the time,amplitude and phase transition time of the voltage sag were realized by using the improved LES algorithm.The simulation model shows that the system's response speed and detection accuracy can be increased by 20% compared with the d-q transformation or HHT method.Based on the above method,the NPQC prototype was developed and verified on the micro-grid voltage drop test platform;the influence of the algorithm on the response time and detection accuracy was analyzed.The experimental results show that the algorithm can detect the voltage sag of micro-grid within 5.2 ms.