Analysis of DC Bias Electromagnetic Characteristics of Three-phase Five-limb Transformers with Different Properties of Load
Three-phase five-limb transformers are widely used in China's distributing networks and are important equip-ment in supply stations.With the continuous development of ultra-high voltage technology,the phenomenon of DC bias has become increasingly frequent in recent years.DC bias is extremely harmful to transformers,including core saturation,increased losses,temperature rise vibration,all of which affect the normal operation of transformers.In severe cases,it may even affect the stability of power grid.Therefore this paper establishes a three-dimensional finite element field circuit coupling calculation model for three-phase five-limb transformers to analyze the current distortion mode and physical rea-sons when DC bias occurs on the load side with different properties of loads.
three-phase five-limb transformerDC biasfield circuit coupling modelexcitation current