电压凹陷特征量检测算法研究

Research on the Detection Method of Voltage Sag Characteristics

对于电压凹陷的三大特征量幅值、持续时间和相位跳变的准确检测是电压质量评估与抑制干扰首先要解决的重要课题。介绍了常用的凹陷特征量的有效值计算法、峰值电压法、基波电压分量法和单相电压变换平均值法 ,并以单相电源为参考电压采用 6 0°延时方法构造了一个虚拟的三相系统 ,借助dq变换将三相电压变换到d q轴 ,提出了有实用意义的d q分解平均值法和d q分解低通滤波法 ,可对单相电压凹陷的三大特征量进行瞬时计算。通过计算机仿真 ,对各种方法的适用性进行了详细的对比分析 ,结果表明本文所提方法具有较好的跟踪特性 ,适合于电压凹陷分析与动态电压恢复器 (DVR)的实时检测应用。

The correct detection of the voltage sag characteristics (its magnitude,duration and phase angle jump) is of great importance for the power quality evaluation and its mitigation.The existing methods including RMS voltage,peak voltage,fundamental voltage component and single phase average voltage are introduced.A fictitious three phase system is created from a reference single phase voltage by a 60 ° delay.With the d q conversion of voltages,two new methods,which are the average method of the d q conversion of instantaneous voltages and the low pass filter method of the d q conversion of instantaneous voltages,are proposed.The proposed methods can instantaneously quantify the phase angle jump,magnitude and duration for single phase voltage sag.By simulative calculation,the applicability of different methods is compared in detail.The result shows that the proposed methods possess the superiority of fast dynamic tracing performance and they are suitable for the analysis of voltage sag and the real time test of DVR.