The frequency response of transmission line (cable) transformers

Interest in transmission line power transformers (TLTs) as pulse transformers is continuing to grow as it becomes clear that these devices have several important advantages over conventional wound transformers. This paper describes the work that has been carried to produce models by which the frequency response of both linear and wound TLT structures can be predicted. Although different types of TLTs are used as voltage transformers, current transformers, pulse isolation transformers and pulse inversion transformers, this paper deals exclusively with transformers with voltage gain. In particular, the paper considers the frequency response of these transformers at low frequencies. It is shown that very low frequency operation is possible and this has important implications for pulse transformers required to transform pulses with long flat tops.