High voltage transmission line transformer

One way to achieve high voltage is to use a step-up transformer. This report describes the design and the construction of a transmission line transformer using a high voltage cable for usage in the high voltage system TTHPM at FOI. Experimental results and equivalent electric circuit simulation models are presented. The measured input and output signals are analysed with parametric models giving the possibility to calculate step responses and Bode plots. A transmission line transformer works in the same way as an ordinary transformer. The input is transformed to the desired output using a step up or a step down configuration. The configuration described here uses a cable designed to withstand high voltage stress, the cable has a semi-conducting layer covering the inner copper wires and the outer plastic shielding. The design has proven to have a high coupling factor even though it uses an air core. This type of transformer is useful in applications where weight is an important factor, another advantage is the simple design and that it can be made to a low cost.