基于Hilbert变换和dq变换的电压暂降检测新方法

New Method for the Detection of Voltage Sag Based on Hilbert Transform and dq Transform

在对电能质量问题的研究中,电压暂降已被认为是影响许多用电设备正常、安全运行的最严重的动态电能质量问题之一。为准确测量电压暂降的特征量,提出了一种基于Hilbert变换和dq变换的电压暂降检测新方法。首先根据实测电压及其Hilbert变换来构造αβ静止坐标系,然后将αβ静止坐标系变换到dq旋转坐标系,最后由dq变换结果求得暂降电压的幅值和相角。与常规的电压暂降检测方法90°延时法的仿真对比实验验证了新方法是正确和有效的,新方法克服了90°延时法存在的短时扰动现象,检测准确度高于90°延时法,并且响应时间更短。

The voltage sag is one of the most serious dynamic power quality problems which influence normal and safe operation of many electric equipments. In order to accurately measure characteristic parameters of voltage sag, we proposed a novel detection method of voltage sag based on Hilbert transform and dq transform. First, the αβ coordinate was structured accordingto actual measured voltage and its Hilbert transform, and then the αβ static coordinate was transformed into the dq rotating coordinate, and finally the amplitude and phase angle of voltage sag were calculated from dq transform outcome. Compared with 90°delay method, conventional voltage sag detection method, the simulation results verify that the new method is correct and effective. The new method which has short response time overcomes the short disturbance of 90° delay method, and has slightly higher detection accuracy than 90°delay method.