Abstract:

Correct sampling is the key technology to localized protection measurement and control device. According to the requirements of the protection and control device, a lowpass filter circuit with reasonable cutoff frequency should be designed to solve the problem of frequency aliasing. Since passing through the filter circuit will affect the amplitude and phase of the fundamental wave and harmonics, the corresponding compensation parameters need to be correct. It theoretical analysis the filter circuit cutoff frequency, amplitude and frequency characteristics as well as phase frequency characteristics，and protection program based on analytic results is designed. According to the amplitude and phase accuracy of the sampling value output of localization protection measurement and control device , the technical requirements of the localized protection measurement and control device are met.

Key words:

localized protection measurement and control device, sampling, lowpass filtering, frequency aliasing, amplitude frequency characteristics, phase frequency characteristics