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March 1998


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Students' Animations Illustrate Tough Power Engineering Concepts

Animations can help explain difficult 3-dimensional concepts, such as rotating magnetic fields in an electric motor. A group of undergraduate and graduate students built six animations to illustrate such hard-to-visualize concepts as the operation of induction motors (top) and DC machines.


A multi-year student animation project may help numerous students more easily grasp abstract, three dimensional, and dynamic power engineering concepts.

Working with Professor Yilu Liu, Chris Richard (EE '98), Jason Hess (EE '97), David Smith (MSEE '96), Boyu Hou (MSEE '97) and Herb Brown (MSEE '95) developed multimedia examples of six power issues that typically confuse many students.

"In power engineering, we have a number of concepts that students traditionally have difficulty understanding because they are hard to visualize," Liu said. "These include transient phenomena on transmission systems, harmonics involved with transformer saturation, magnetic fields, and DC machine operation, among others."

One difficult concept she cited is the effect of line termination on the step front wave traveling along the transmission line. "Students accustomed to the short wires in their electronics labs are not used to thinking about voltages and currents 'bouncing' back when they reach their destinations. To address this problem we created a series of animations with different transmission line terminations.

"Another common problem," she continued, "is that students just don't get a good feel for the true vulnerability of the power system. We decided to illustrate this by showing lightning striking a line and tracking the resultant surge as it heads down the line to the transformer, where it is shunted off by a surge arrestor. This way the students can actually visualize the relative size of the surge, and understand what damage could result without adequate protection."

Other concepts are difficult to visualize because they involve three-quadrant plots, such as the harmonics introduced into the excitation current by the saturation of the magnetic core of a transformer, she explained. "For this concept, our animation has a built-in navigation system that lets the user move back and forth between frames to study the changes."

"There have been computer animations developed to illustrate some of these concepts in the past," Liu said. "However, they typically took a very long time to develop, and required hardware and software that were not available to the typical student. Authoring packages are now much faster and easier to use. Moreover, undergraduates now have access to enough computing power to run animations.

"The technology has reached the point where it is feasible to both create and use animation to teach these difficult concepts."

Liu's team created the animations in Micromedia Director 5 and 6. The six modules fit onto a single floppy disk, and need no special software to run in a Windows environment. Plans are being developed to make the animations available to EE undergraduate students.

The four-year project was funded in part by the National Science Foundation (NSF).

The Bradley Department of Electrical and Computer Engineering
Virginia Tech

Last Updated, April 29 1998
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