Analysis of Voltage Distribution Characteristics in UHVDC Converter Transformer Winding Based on the Reduced-Scale Model

Based on the similarity theory, a reduced-scale model is proposed to study the voltage distribution characteristics in ultrahigh-voltage direct current converter transformer windings under the impulse voltage. Through comparing the distribution characteristics of electric field intensity and magnetic flux intensity of the scale model with that of the original model, the effectiveness of the reduced-scale method is verified. Furthermore, the actual production design is also considered in the model. The matrices of the inductance, capacitance, and resistance parameters for the reduced-scale model are obtained by finite element method. Then, the multi-conductor transmission line model is set up to study the propagation process of impulse voltage along the windings of the converter transformer. The voltage distribution curve is obtained under a standard lighting impulse voltage and the turn-to-turn fault is taken into consideration as well. The simulation results are the basis for the following experimental study.