Snap Crackle & Pop! Three Stages of High Voltage Testing
Andrew Berry
Doctoral Candidate
University of Canterbury
How do you conduct high voltage testing in a difficult location? How do you apply a 47kV AC test voltage, to a stator at one of Australia’s largest power stations? And how do you do any of that without an unlimited local supply?
This paper describes the work conducted on a 23kV, 660MW generator in Australia. It covers the specialty three stage partial core resonant transformers used, and describes the tests conducted on site.
The transformers used were designed and built at the University of Canterbury, and constructed specifically to allow for a lightweight and portable set of test equipment. The set utilises a variable inductance in order to manipulate a resonant circuit, which consists of the inductive supply of the testing transformers and capacitive load of the stator under test. Establishing this resonance allows a limited primary supply to energise substantial pieces of plant to the voltages required for testing.
Testing involved tan delta assessment, partial discharge measurement, and a high potential dielectric withstand. All tests were conducted on each of the three phases of the generator separately, and yielded passing results.
Andrew Berry is a hands on engineer, and is always at ease while holding a spanner. Having completed his bachelors in engineering with first class honours at the University of Canterbury, he stuck around and was drawn in to the High Voltage Laboratory, where he has since been undertaking postgraduate research. Based there he has built coil guns, explosive art installations, and partial core transformers. He has had involvement with numerous electricity industry investigations relating to generator, transmission and distribution assets. Andrew is always happy for a chat (or to receive compliments on his beard).