Analysis of DC Magnetic Bias Influences on Transformers

This paper is aimed at DC magnetic bias influences on power transformers which located close to an UHVDC ground electrode. The reasons for causing the DC magnetic bias and its influences on transformers are discussed. As the grounding DC current injected by the ground electrode of UHVDC project keeps increasing, the DC current flowing through transformer's neutral point, transformer vibration and noise level have been measured. By analyzing the testing results, how AC transformers are influenced by the DC magnetic bias have been researched.