Automatic impulse voltage routine testing of distribution transformers

Distribution transformers are often produced by highly automated production lines. Overall factory throughputs for small transformers sometimes reach one unit per minute. This throughput requires a fully automatic impulse test system capable of generating and analysing an impulse even few seconds. In addition, production information has to be integrated and verified by a host computer retrieving instantaneous pass/fail information from the impulse test system. High speed, high system reliability and correct pass/fail decisions are the challenges in implementing such an automated test system. In future, sophisticated analysis tools such as coherence and transfer functions with tolerance bands could be implemented. This allows a further refinement of pass/fail decisions which have to be investigated