Quantitative analysis of transformer DC bias risk influencing factors

DC current intrusion into the transformer makes the transformer magnetic density working point shift, generating DC bias magnetism, which jeopardizes the safe operation of the power system. In order to achieve this, firstly, the mechanism of DC bias generation is analyzed and a simulation model of DC bias current is established, secondly, a DC bias calculation model is constructed in Xinjiang based on the measured soil resistivity and AC grid structure, and the influencing factors of DC bias current are quantitatively analyzed, and lastly, the influence of the DC bias current on transformer DC resistance and transformer DC resistance is investigated and analyzed in order to provide a better solution for the safe operation of power system. Finally, by comparing and analyzing the calculation results, the influence of different earth resistivity, grounding pole distance and transformer DC resistance on DC bias current is obtained, which provides some guidance for the prevention of DC bias in existing substations and substations in the planning period.