Transients in Testing Transformers Due to the Generation of Switching Impulses

Testing transformers are used to advantage for the generation of switching impulses. Nevertheless, transients and overvoltages do occur, particularly in cascaded transformers with several stages. Different types of transients were investigated, namely the saturation of the iron core, the voltage distribution in cascades and the oscillations inside the HV winding. In addition to the measurements, digital computations with special equivalent circuits were carried out. The agreement between the results of measurements and calculations enabled suitable methods for the prevention of overvoltages to be devised.