动态电压质量问题检测方法

就目前电能质量问题中常见的电压波动(骤升、骤降、闪变、谐波)检测技术进行了探讨。对经典的和目前众多热点研究的电压波动检测技术进行了分析,包括锁相技术中的过零锁相和软件锁相环(SPLL),以及波动特征量检测中的均方根值法、dq0变换法、改进窗口傅里叶变换法及研究最多的小波变换法,并对各种算法的优、缺点和适用范围作了分析、比较。过零锁相即硬件锁相(PLL)由鉴相器、环路滤波器、压控振荡器及分频器组成,其原理和结构较简单,但动态性能较差,且在畸变电压输入时锁相效果变差;软件锁相环是一种基于瞬时无功理论的锁相方式,其结构比较简单、动态响应速度快、能准确地锁定电源电压的基波正序分量,对谐波有很强的抑制作用,一般无需滤波环节。最后,对电压波动检测技术进行了总结。

Detection methods for dynamic voltage quality

Several common detecting techniques for voltage fluctuations such as swells,sags,flickers and harmonics are discussed.Classical and modern detecting techniques for them are analyzed,including zero-crossing PLL(Phase Locked Loop) and SPLL(Software PLL) in the phase locked method,and root mean square method,dq0 transformation method,improved window Fourier transformation as well as widely used wavelet transformation in the fluctuation character extraction.The merit and disadvantage of each algorithm are compared.The zero-crossing PLL i.e.hardware PLL,is comprised of PFD(Phase-Frequency Detector),loop filter,VCO(Voltage Control Oscillator) and frequency divider.It is really simple but poor in dynamic performance,and even worse in phase lock effect with distorted input voltage.Based on the instantaneous reactive power theory,the SPLL is simple,high speed and can exactly lock the fundamental positive sequence of source voltage,with strong suppression for harmonic and needless filter.Finally,detecting techniques for voltage fluctuation are concluded.