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Teaching Power Transformer Testing to Undergraduates

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2019 ASEE Annual Conference & Exposition


Tampa, Florida

Publication Date

June 15, 2019

Start Date

June 15, 2019

End Date

June 19, 2019

Conference Session

Energy Conversion and Conservation Division Technical Session 1

Tagged Division

Energy Conversion and Conservation

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Paper Authors


Glenn T. Wrate P.E. Northern Michigan University

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Glenn T. Wrate received his B.S.E.E. and M.S.E.E. from Michigan Technological University (MTU) in 1984 and 1986, respectively. While attending MTU, he worked for Bechtel Power Corporation on the Belle River and Midland power generating stations. After graduating MTU, he worked for the Los Angeles Department of Water and Power from 1986 to 1992, primarily in the Special Studies and High Voltage DC (HVDC) Stations Group. He returned to MTU in 1992 to pursue a Ph.D. in Electrical Engineering. While completing his research he worked in the relay testing group at Northern States Power Company in Minneapolis.
After obtaining his Ph.D., Glenn accepted an appointment as an Assistant Professor in the Electrical Engineering and Computer Science department at the Milwaukee School of Engineering (MSOE). In 1999 he was promoted to Associate Professor, in 2001 he won the Falk Engineering Educator Award and was promoted to head the Master of Science in Engineering (MSE) program. He received the Karl O. Werwath Engineering Research Award in 2003. In 2004 he moved from the MSE program to take over the Electrical Engineering program. After guiding the program through accreditation, he stepped down in 2007.
Dr. Wrate has now returned to his boyhood home and is teaching as a full professor at Northern Michigan University. He is a member of HKN and IEEE, a Registered Professional Engineer in California, and is a past chair of the Energy Conversion and Conservation Division of ASEE.

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Many educational electrical power laboratories do not have access to utility-sized three-phase and single-phase power transformers, voltage regulators, and utility-grade instrument transformers. At XXX, a utility consortium has donated a 2500-kVA, three-phase, General Electric, 32.8-kV – 2,400-V, grounded wye to delta, type OA-T transformer; a 333-kVA, single-phase, McGraw-Edison, 34.4kV – 277-V, type OA transformer; five voltage regulators, and several current and potential transformers. With test equipment obtained from a grant from the Department of Energy (DOE) and other equipment donated by local industry, the students perform insulation resistance, transformer turns ratio, oil breakdown, and power factor/dissipation factor testing on these transformers. These tests are in addition to the standard laboratory tests performed on small transformers to determine polarity, turns-ratio, equivalent circuit parameters via open- and short-circuit tests, and voltage regulation. This paper will discuss the problems encountered running these tests with undergraduates, including safety concerns. It will also discuss the students’ interactions and their impressions of the testing, and look at methods to evaluate how well they learned the testing methods and the transformer operational concepts. The tests on the large power transformers are performed in this order: 1) a Megger MIT525 is used to perform the insulation resistance and polarization index tests, 2) a Megger TTR-320 is used to perform the transformer turns-ratio tests, 3) a Megger OTS 60 PB or Hipotronics OC-60-A portable oil tester is used to perform a breakdown voltage test on the oil from a Hampden H-OFT-180 oil-filled transformer trainer, and 4) a Megger Delta 3000 is used to perform the power factor/dissipation factor tests at 10 kV. In addition to learning how to use the test equipment safely, the students must also learn the software to run the tests and collect the data. It is hoped that this paper provides insight into testing large power transformers and suggestions for others who are interested in teaching these tests.

Wrate, G. T. (2019, June), Teaching Power Transformer Testing to Undergraduates Paper presented at 2019 ASEE Annual Conference & Exposition , Tampa, Florida. 10.18260/1-2--33352

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