基于db4小波的短时电压变动检测和录波实现

Detection and fault record of short duration voltage variation based on db4 wavelet

针对基于50Hz基波的短时电压变动信号检测和数据压缩对小波基的特殊要求,利用仿真实验证明了db4小波在短时电压变动检测和数据压缩与重构方面的独特优势,提出了一种基于db4小波的短时电压变动检测和录波实现的方法;提出了可以利用短时电压变动后的1/2个周期数据窗求短时电压变动的幅值。利用db4小波对短时电压变动信号就行了时频分析,准确得到了短时电压变动发生的起止时刻和短时电压变动幅值,实现了短时电压变动数据压缩与重构和故障录波。介绍了小波变换的基本原理,给出了算法仿真和系统实现的结构框图。通过实验仿真,证明了算法的可行性和准确性。在此基础上,利用Lab VIEW设计了短时电压变动信号发生和检测系统。运行结果表明,系统测量准确可靠,性能优良,操作简单方便。

According to the special requirements of detection and data compression for the 50Hz fundamental short du-ration voltage variation signals to the wavelet basis , the best effective wavelet basis db 4 was gotten by using simulation experiment , which had excellent performance both on detection of short duration voltage variation and digital fault data recorded compression and decompression .The amplitude of short duration voltage variation is gotten by 1/2 cycle data window .The db4 was applied for time-frequency analysis of short duration voltage variation signals , to accurately esti-mate the starting and ending moments and amplitude of the short duration voltage variation , and digital fault data re-corded compression and decompression is achieved .Basic principles of the wavelet transform were briefly introduced , and then the algorithm simulation and the system block diagram were given .Simulation experiment results verify the feasibility and accuracy of this algorithm .Moreover , a signal occurrence and detection system of short duration voltage variation based on LabVIEW was developed .The operation results show that system is easy to operate with accurate and reliable measurement and excellent performance .