Development of Air Core Type 500 kV HV Pulse Transformer

Cylindrical type air core pulse transformers capable of passing high voltage and energy pulse waveforms with high efficiency and low distortion require a much more delicate design balance of physical dimensions and electrical parameters than iron or ferrite core units. The structure of an air core high voltage pulse transformer is relatively simple, but considerable attention is needed to prevent breakdown between transformer windings. Since the thickness of the windings in spiral type is on the order of sub-millimeter, field enhancement at the edge of the windings is very high. It is, therefore, important to find proper electrical insulation parameter to make the system compact. Several shapes of the winding are considered for air core pulse transformer development. Requirements of the transformer are 170 nH inductance at primary side, 500 kV. In this paper, we will describe a design procedure, parameters, measurement and experiment results of air core type 500 kV HV pulse transformer.