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Teaching Power Circuit Breaker Testing to Undergraduates

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2018 ASEE Annual Conference & Exposition


Salt Lake City, Utah

Publication Date

June 23, 2018

Start Date

June 23, 2018

End Date

July 27, 2018

Conference Session

Energy Conversion and Conservation Division Best Papers

Tagged Division

Energy Conversion and Conservation

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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 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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Most educational electrical power laboratories do not have access to a working 69-kV SF6 Puffer Circuit Breaker. At XXX, a utility consortium has donated a Siemens SP-72.5-40, 1200 A continuous, circuit breaker. The students perform travel time, insulation resistance, contact resistance, and power factor/dissipation factor testing on this breaker. This paper will discuss the problems encountered running these tests with undergraduates, including safety and power concerns. It will also discuss the student’s interactions and their impressions of the testing, and look at methods to evaluate how well they learned the testing methods and the circuit breaker operational concepts. The travel time test requires that both 120 Vac (for the compressor) and 125 Vdc (for the controls) be provided to the breaker. On the breaker tested, a large spring is used to open the interrupters, while a pneumatic system is used to close the breaker. A Doble TDR 900 is used to perform the test. This test instrument has inputs for 1) the linear transducer that measures the movement of the operating mechanism, 2) the status (open or close) of all three interrupters, 3) the current through the trip and open coils, and 4) the battery (or dc supply) voltage. It controls the circuit breaker tripping and closing so that trip, close, Trip-Free (CO), Reclose (O-C), C-O, O-CO, and O-C-O tests can be run. A Megger MIT525 is used to perform the insulation resistance and polarization index tests. Power to the breaker must still be provided for this test since the interrupters are tested in both open and closed positions. A DV Power Micro Ohmmeter RMO200G is used to perform the contact resistance test at 200 A. Finally, a Megger Delta 3000 is used to perform the power factor/dissipation factor tests at 10 kV. This test also requires that the circuit breaker is powered, since, again, the interrupters are tested both the open and closed position. 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 in testing large circuit breakers and suggestions for others that are interested in running these tests.

Wrate, G. T. (2018, June), Teaching Power Circuit Breaker Testing to Undergraduates Paper presented at 2018 ASEE Annual Conference & Exposition , Salt Lake City, Utah. 10.18260/1-2--31060

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