Simulation analysis on the capacity occupancy of reactive power equipment under DC bias of transformers

Le résumé fourni par la source

When the high voltage direct current (HVDC) system operates in ground-return-mode (GRM), ground return current with high amplitude up to several thousand amperes will penetrate into the earth. Such DC current will flow through AC lines with star-connecting and grounding at both ends, and intrude the neutral point of the transformers of the line in turn. Therefore, it will increase the reactive power consumption of the transformer and occupy the capacity of reactive power compensation equipment, as well as threaten the security and stability of the power grid. A simulation model of typical substation system operating under DC bias is established, based on which the quantitative analysis of the variation of the excitation current and the condition of reactive power consumption for transformers under different bias current is carried out. The analysis results show that the excitation current is seriously distorted and the reactive power consumed increases sharply under DC bias current with high amplitude, which occupies a large amount of reactive power compensation equipment capacity. Therefore, extremely adverse impact can be brought out on the reactive power balance and the voltage regulation of the power grid. In addition, the results of this paper are of significant reference value for researches on the reactive power characteristics of DC bias as well as the support capability of short-circuit voltage under DC bias.

Ce résumé expose les affirmations des auteurs. BNTIC ne l’interprète pas comme une validation indépendante des résultats.