Review of research on measurement technologies of DC high voltage

High Voltage Direct Current (HVDC) transmission technology as a new mode of power transmission is widely used all around the world and becomes more and more important because of its low cost and high reliability. Direct Current (DC) high voltage transformers are one of the most important equipment in HVDC transmission systems. On the basis of the application of DC high voltage transformers, in this paper the main principles and characteristics of DC voltage transformers are summarized. The key issues of resistance/resistance-capacitance voltage dividers are analyzed in practical use. Considering the problems generated when using optical sensing principle for DC voltage measurement, this paper also presents some researches on this issue.