WANG Zezhong, WANG Huan, YANG Xiaoxiao, et al. DC Magnetic Bias Analysis of UHV Transformer Based on Axisymmetric Model[J]. High voltageapparatus, 2020, 56(4): 87-94.
WANG Zezhong, WANG Huan, YANG Xiaoxiao, et al. DC Magnetic Bias Analysis of UHV Transformer Based on Axisymmetric Model[J]. High voltageapparatus, 2020, 56(4): 87-94. DOI: 10.13296/j.1001-1609.hva.2020.04.014.
DC Magnetic Bias Analysis of UHV Transformer Based on Axisymmetric Model
Aiming at the time-consuming problem of the DC magnetic bias calculation for three-dimensional model of UHV autotransformer
an equivalent axisymmetric two-dimensional model is established by analyzing the features of magnetic circuit structure of UHV Transformer so as to effectively reduce the computation scale of DC magnetic bias.The correctness and effectiveness of the axisymmetric model are verified by comparing with the three-dimensional model.The axisymmetric model can complete the calculation of DC magnetic bias in a relatively short time
effectively reduce the computation workload
and guarantee the accuracy of calculation.And it has a certain advantage over the three-dimensional model.Based on the axisymmetric simulation model
the influences of series resistance and time step on the calculation accuracy of DC magnetic bias are analyzed
and the range of the series resistance is obtained.Finally
the DC magnetic bias of UHV transformer under different DC current is calculated according to the magnetic-circuit coupling principle in time domain
and the electromagnetic effect of DC magnetic bias is analyzed.The results show that with the increase of DC magnetic bias current
the waveforms of excitation current and winding current distort seriously
and large harmonic components are produced
which will threaten the safe and stable operation of transformers and even the power system.