电压凹陷的改进S变换检测方法  

Detection Method of Voltage Sag Using Modified S-transform

作　　者：易吉良[1] 彭建春[1] 

机构地区：[1]湖南大学电气与信息工程学院,湖南长沙410082

出　　处：《湖南大学学报（自然科学版）》2010年第10期52-56,共5页Journal of Hunan University:Natural Sciences

基　　金：国家自然科学基金资助项目(50677015)

摘　　要：提出了一种利用改进S变换模时频矩阵检测电压凹陷特征量的方法.为达到最优分析性能,在保证基频幅值向量平直性的基础上,使其过渡时间最小,以此确定改进S变换的窗宽系数,从而能够准确检测出持续时间小于2个周期的短时电压凹陷幅值.提出利用基频幅值差分向量检测电压凹陷的起止时刻,以克服现有S变换方法对噪声敏感和定位效果受突变幅度影响的缺陷.通过与S变换方法的比较,证明了本文方法明显提高了电压凹陷幅值检测能力和起止时刻定位能力.This paper presented a new detection method of voltage sag feature value,which was extracted from the module matrix of modified S-transform.In order to get the optimal performance,the parameter related to time-frequency resolution was determined on the basis of the flatness and minimal transition time.By means of the optimal time-frequency resolution,the amplitude of voltage sag duration less than 2 cycles could be detected accurately.The difference vector of base frequency was employed to detect sag duration so as to overcome the flaws of exiting S-transform-based methods,whose effects were unsatisfied when there were strong noise and no amplitude abrupt.A comparison between S-transform-based method and modified-S-transform-based method was made,and the results showed that the later was superior to the former in magnitude detection and duration localization.

关 键 词：电压凹陷 改进S变换 凹陷幅值 定位 

分 类 号：TM711[电气工程—电力系统及自动化]