Development method of a new broadband high precision voltage divider and comparative analysis of measurement accuracy

The measurement and control of harmonics in extra high voltage direct current (EHV DC) transmission lines is an important guarantee for the safe operation of the EHV DC transmission system. According to the operation it is concluded that when the grid frequency fluctuates, the frequency of AC harmonics will also fluctuate. In the face of frequency fluctuations, the measurement results obtained from the raw data have a large error and have exceeded the design requirements. In order to explore the proper measurement method, further research on voltage harmonics in AC-DC networks under wide band is needed. The new wide-band high-precision voltage divider is the main equipment for measurement and control protection in extra-high voltage DC transmission lines. In this paper, the new wide-band high-precision voltage divider is described from several aspects, such as development method, stray capacitance additional error solution method, experimental test, and experimental result analysis. The experimental results show that the new wide-band high-precision voltage divider can accurately measure the harmonics in the AC-DC transmission network and is verified by Fourier analysis, and the measurement accuracy can meet the accuracy requirements of less than 0.2% at 50Hz and less than 1% from 50-3000Hz.