摘要
低频振荡暂态是电力系统中常见的一种电能质量扰动,其直接影响电力系统的安全、稳定运行。通过对影响时频分析算法检测精度的窗函数进行了研究,提出一种基于优化窗函数改进S变换的低频振荡暂态检测方法。首先,对时频分析算法中窗函数随检测频率变化的改变特性进行分析,确定了适用于低频振荡暂态扰动检测的优化窗函数,并利用其构造了改进S变换算法;其次,通过利用卷积定理、Fourier变换及其逆变换,推导了改进S变换算法快速实现的计算表达式,获取了包含信号幅值、相位信息的二维时频矩阵,给出了改进算法的实现流程;最后,采用包含低频振荡暂态扰动的电网信号对改进算法进行了测试。该优化算法对低频振荡暂态扰动表现出相对最佳的时频能量聚集性能,实际实验中所测得扰动中心频率为600 Hz,与扰动的生成频率相吻合,验证了改进算法的可行性和有效性。
Low-frequency oscillation transient is a common type of power quality disturbance in power system,directly affecting the safe and stable operation of power system.A low-frequency oscillation transient detection method based on an improved S-transform using an optimized window function is proposed.Firstly,the changing characteristics of the window function with detection frequency in time-frequency analysis algorithms are analyzed,identifying an optimized window function suitable for detecting low-frequency oscillation transients.This optimized window function is then utilized to construct an improved S-transform algorithm.Secondly,through the application of the convolution theorem,Fourier transform,and its inverse transform,a computational expression for the fast implementation of the improved S-transform algorithm is derived,resulting in a two-dimensional time-frequency matrix containing signal amplitude and phase information.The implementation process of the improved algorithm is provided.Finally,the improved algorithm is tested using power grid signals containing low-frequency oscillation transients.The algorithm demonstrates relatively optimal timefrequency energy concentration performance for low-frequency oscillation transients.In practical experiment,the detected disturbance center frequency is 600 Hz,consistent with the generation frequency of the disturbance,verifying the feasibility and effectiveness of the improved algorithm.
作者
江青柳
梁成斌
陈光贵
王嵘瑜
贺青
JIANG Qingliu;LIANG Chengbin;CHEN Guanggui;WANG Rongyu;HE Qing(College of Electrical Engineering,Guizhou University,Guiyang,Guizhou 550025,China;Guizhou Institute of Measurement and Testing,Guiyang,Guizhou 550025,China;Department of Electromagnetic,National Institute of Metrology,Beijing 100029,China)
出处
《计量学报》
北大核心
2025年第1期133-140,共8页
Acta Metrologica Sinica
基金
贵州省科技支撑计划项目(2024一般136)
贵州大学自然科学专项科研基金(202313)。
关键词
电磁计量
电能质量扰动
改进S变换
低频振荡暂态
窗函数优化
时频能量聚集
electromagnetic metrology
power quality disturbance
modified S-transform
low-frequency oscillatory transients
optimization window function
time-frequency energy concentration
