The quality of power quality directly affects the quality of industrial products. There are three standards for evaluating power quality. The first is voltage, which includes voltage fluctuation, voltage offset, voltage flicker, etc.; second is frequency fluctuation; and finally is the voltage waveform quality, that is, the symmetry of the three-phase voltage waveform and the distortion rate of the sine wave. , that is, the proportion of harmonics. Our country has clear standards and specifications for the three aspects of power quality.
With the development of science and technology, as well as the improvement of industrial production levels and people's living standards, a large number of nonlinear electrical equipment are put into operation in the power grid, resulting in an increasing proportion of harmonic components in the power grid. It not only increases the power supply loss of the power grid, but also interferes with the normal operation of the power grid's protection devices and automation devices, causing malfunction or refusal of these devices, directly threatening the safe operation of the power grid.