The invention provides an
electric energy quality regulation method,
voltage temporary
change detection method and dynamic
voltage restorer. The
voltage temporary
change detection method comprises thefollowing steps: acquiring an electric
grid voltage signal, selecting a
decomposition scale, performing initial
wavelet transformation, and acquiring
wavelet coefficients of a first set
frequency band and a second
frequency band; performing single reconstruction for the
wavelet coefficient of the first
frequency band, and acquiring a fundamental wave
signal of the electric
grid voltage; performing secondary wavelet transformation, acquiring a first frequency band component and a second frequency band component; performing single reconstruction for the second frequency band component, and determining start and
stop time of occurrence of voltage temporary change; and performing single reconstruction for the first frequency band component, and determining fundamental wave electric
grid voltage temporary amplitude information. Double wavelet transformations are used for detection of the voltage
signal containing temporary change and
harmonic waves, based on wavelet transformation
multiresolution analysis characteristics and singularity detection property, decoupling of
harmonic waves and temporary change
electric energy quality problems is solved,
noise influence is restrained, accurate positioning of a temporary change signal is completed, time
delay can be reduced effectively, and influence on electric grid real-time compensation is reduced.