摘要
针对动态电压恢复器对电压暂降特征量检测的实时性和准确性要求,与移相小角度的αβ-dq变换相结合,提出了一种使用双结构数学形态学滤波的快速电压暂降检测方法。即将构造出的双结构数学形态学滤波器对电网单相电压中的谐波、噪声等干扰进行预处理后,将待测单相电压移相一个小角度形成相互垂直且正交的αβ两相电压,再采用αβ-dq变换并用数学形态学滤波器代替传统的二阶巴特沃斯低通滤波器实现对非直流量的滤波,实现实时、准确地检测电压暂降发生的起止时间、暂降幅值和相角变化;为避免锁相过程产生的延时和输出误差,用基波特征参考值代替锁相环节;该方法原理清晰、计算简单。仿真实验结果表明该方法具有抗干扰、延时小、检测结果准确性高的优点。
A method using a double structure of mathematical morphology filter for fast voltage sag detection is proposed in this paper to meet the requirements of both real time property and accuracy for the voltage sag detection characteristics of the dynamic voltage restorer, which combines a small angle shifting in phase with aβ-dq transform. After being pretreated by the constructed double structure mathematical morphology filter, the single-phase voltage containing harmonics and noises shifted in phase with a little angle and then become two perpendicular and orthogonal aβ phase voltage. And then the aβ-dq transform is conducted and mathematical morphology filter is utilized to replace the traditional second-order butterworth low-pass filter to smooth the straight flow. By this method, the real-time and accurate detection of voltage sag start-stop time and temporary decline in value and phase angle change can be realized. To avoid delay and output error produced during lock process, the fundamental characteristics of the reference value are used to take place of the phase-locked loop section. The principle of the method is concise and simple. The advantages of anti-interference, small time delay and good accuracy of the method are demonstrated by the simulation results and tests.
出处
《电力科学与工程》
2016年第1期58-63,共6页
Electric Power Science and Engineering
