High Voltage Pulse Transformer Employing Magnetic Self-Insulation

High-voltage pulse transformers are key elements of many pulsed power systems, where they provide an attractive alternative the Marx generators for providing short rise time voltage pulses. Unfortunately, the commonly used forms of insulation cannot be used above 500 kV, without considerable added complexity. Immersion in oil is effective, but leads to a heavy and bulky unit. Magnetic insulation provides the only practical form of insulation for much of the equipment used in ultrahigh voltage pulsed-power systems, including high power transmission lines and plasma opening switches. Although its adoption in transformers would bring significant advantages in both size and weight, a number of seemingly insurmountable problems have so far prevented this. Experiments on a 0.5 MV prototype transformer in which the magnetic field required for magnetic insulation is provided by the transformer current (ie magnetic self-insulation) have shown that the electromagnetic and mechanical design adopted can remove the previous difficulties. Details of the design are presented including theoretical predictions made using filamentary modelling, ANSOFTreg; software and MAGICreg; software, which are all valuable tools for use in the design of future transformers