A Review of Research on Transformer DC Bias Caused by HVDC Transmission

Abstract The construction of AC and DC transmission in China is accelerating. And the grid is getting closer, which will make the grid structure strong. However, the tightly connected power grid is more vulnerable to space weather and HVDC. Now, the researches on transformer DC bias were summarized, and the researching methods and achievements were analyzed. The main reasons and basic theory were introduced, and so did the influences to transformer. The method is generally to establish a corresponding calculation model through actual measurement, simulation and calculation, and limiting, isolating, injecting DC current are main restraining measures.