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Special Report ­
Information Technology

 April 1997



Links to a More Reliable Power Network

photo of USA at night

Keeping the lights on - Advances in information and communications technology can improve the reliability, quality, and efficiency of electric power networks. Measurement systems developed by engineers at Virginia Tech use the Global Positioning System to obtain precise, simultaneous measurements along the grid.

As computers grow more capable, they are being used in increasing numbers to help the world's power networks operate more securely, more reliably and more economically. The time is nearing when incidents such as those that caused last summer's blackouts on the west coast would be isolated and accommodated before they could disrupt entire regions.

The vision involves fitting every power station on the grid with measurement devices and computers, which would communicate via land lines and use the transmission of Global Positioning System (GPS) satellites to obtain precise, simultaneous measurements from power networks.

These simultaneous measurements from the network would be used by different levels of a hierarchy of control centers. At the local area level, the data would be used to isolate a problem if something goes wrong. The power equipment involved in the incident could instantly be isolated to minimize disruption and keep it from affecting the whole grid.

At the regional or national level, the data would be used to determine precisely how much energy is required across the region, where would be the least expensive place for it to be generated, and how best to route it in times of stress on the power networks. This would enable utilities to produce power more efficiently and economically. The data also would be used to manage the grid's recovery from major disruptions caused by lightening strikes, tornadoes, floods or fires.

"We are nowhere near that vision," said Professor Arun Phadke, director of the Department's Center for Power Engineering. "Although we do have the equipment and the computer tools."

Phadke and his group at Tech developed the synchronized phasor measurement unit in the early 1980s. The device is a microprocessor-based system using GPS satellite signals that measures the voltages and currents at a power station. The unit was commercialized in 1985 and is manufactured by Macrodyne. To date, more than 200 devices have been installed worldwide. However, to network the entire U.S. power grid would require tens of thousands of installed devices.

"We really need more devices installed," Phadke commented. "Everybody is investigating the benefits of the device...most major companies have a few on their system and are assessing their performance.

"Although the device is more than 15 years old, its design and function have been shown to be precisely what we need for the foreseeable future. We still measure voltage and current," Phadke said. "What has changed is what can be done with the measurements we make."

"As computers have become more powerful, it has enabled us to develop many more applications. It is the enhanced applications of these measurements that will bring about the reliable, economical power network of Phadke's vision.

"The devices cannot measure without a computer," he explained. "And the data collecting and decision-making at the local and regional control centers require sophisticated processing and computation."

Utilities operate with tight profit margins, and the cost of installing computers and devices at every power station can seem daunting. However, ultimately, the sophisticated measurement systems and advanced application software will bring about a revolution in how we manage our supply of electric energy.


The Bradley Department of Electrical Engineering
Virginia Tech

Last Updated, June 10, 1997
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