Public Release: 

First Dynamic Voltage Restorer Enters Utility Service

Electric Power Research Institute

-- A new Custom Power device keeps sensitive industrial equipment operating through voltage fluctuations to maintain profits --

Anderson, South Carolina -- November 22, 1996 -- A momentary deviation in voltage that might stop production is quickly corrected at a rug manufacturing plant due to the world's first Dynamic Voltage Restorer (DVR).

The DVR, an electronic device that protects sensitive equipment from voltage fluctuations on a power line, keeps the equipment operating by rapidly injecting energy onto the line to compensate for a disturbance.

Developed by Westinghouse with funding from Duke Power and the Electric Power Research Institute (EPRI), the first DVR entered commercial service on the Duke Power system on August 26. The DVR improves the quality of power delivered to Orian Rugs in Anderson, South Carolina. Formal dedication of the facility is scheduled for today.

"A sharp voltage sag can cost us thousands of dollars," says Rick Gilbert, yarn production and technical manager at Orian. "First you have to clean up the mess of yarn that was on its way to a winder, then you may have to spend two hours restarting the equipment."

A voltage sag is a temporary drop in electric voltage from a momentary power disturbance. Disturbances can be caused by lightning strikes or trees that contact power lines of the interconnected electric distribution and transmission system.

The DVR on Duke's system has already prevented downtime at Orian Rugs by correcting a severe voltage sag, which occurred on October 20.

"We are very encouraged by the DVR's response to this event," says Steven Whisenant, system power quality manager at Duke Power. "We have been working with Orian to make their equipment less susceptible to voltage sags, but still needed to improve the delivery system. Upgrading the distribution feeder to a transmission line was not a viable option, and the DVR provided an alternative."

As computerized control becomes more common in many industrial processes, momentary power disturbances, such as voltage sags, swells, transients, or harmonics, that once might have gone unnoticed can now cause whole assembly lines to grind to a halt. Such disturbances can cause hours of lost production time which translates to a significant loss in profits.

Orian Rugs is located at the end of a long distribution feeder owned by Duke Power. Its highly-automated yarn manufacturing and rug weaving facility has been particularly affected by voltage sags caused by problems occurring "upstream" along the line.

The DVR is the latest and most advanced of several electronic power controllers that are part of the EPRI's Custom Power program. Custom Power is value-added power that electric utilities and other service providers will offer their customers.

"Now, Custom Power devices, like the DVR, are providing utilities better ways to control their distribution systems and improve power quality for customers with sensitive loads," said Karl Stahlkopf, vice president of EPRI's Power Delivery Group.

The DVR was developed at Westinghouse's Science and Technology Center in Pittsburgh. Two similar DVRs, one in Australia and one in Florida, will be commissioned by the end of this year.

"The advanced power electronics technologies now becoming available enable utilities to add new value in their power delivery systems by providing levels of power quality never before possible, to serve customers with sensitive loads," said John Kessinger, general manager of Westinghouse's Energy Management Division.

EPRI, established in 1973 and headquartered in Palo Alto, California, manages science and technology R&D for the electricity industry. More than 700 utilities are members of the Institute which has an annual budget of some $500 million.

Westinghouse Power Generation, headquartered in Orlando, Fla., is a market and technology leader in the global power business offering generation, transmission, and power delivery products and services.

Based in Charlotte, N.C., Duke Power is one of the nation's largest electric utilities -- serving 1.8 million customers in North Carolina and South Carolina.

(The Duke DVR has a rating of 2 MVA with 660 kJ of energy storage, and is capable of restoring a 50 percent voltage sag to 100 percent for a period of 30 cycles. Commercial orders are now being accepted for DVRs with ratings from 2 to 20 MVA, in 2 MVA increments.)


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