Experiences testing large machines with high-voltage partial-core transformers


Dr Andrew Lapthorn
University of Canterbury

For many reasons, such as commissioning, maintenance and performing investigations; it may be necessary to perform high-voltage tests on large rotating plant. These tests can include, partial discharge investigations, insulation power factor and ac withstand tests or high potential testing. To perform these tests the stator’s insulation needs to be raised to a high voltage.

This can be challenging as the stator’s insulation capacitance can be significant and requires large amounts of reactive power to energise, which can put a strain on the current capacity of the low voltage distribution board. Often reactive power compensation in the form of high-voltage tuneable inductors is required adding complexity and costs to the testing. At the University of Canterbury we have developed a unique solution to this problem in the form of a high-voltage partial-core transformer. This presentation will discuss the development of this technology as well as highlight its application on several sites in New Zealand and Australia.

Andrew received an NZCE from Christchurch Polytechnic in the late 1990’s and proceeded to work as an electronic technician for a number of years. He then went to the University of Canterbury and received his BE(Hons) and PhD in 2008 and 2012 respectively. He is currently employed as Senior Lecturer at the University of Canterbury specialising in electric machines and high voltage engineering. Andrew is responsible for managing the high voltage laboratory at UC and regularly engages with the electricity industry through consultancy and high voltage testing services. He is a member of Engineering New Zealand and the Institute of Electronic and Electrical Engineers.