EMERSON'S ABILITY TO SEAMLESSLY INTEGRATE EXISTING I/O REDUCES COSTS AND TIME
08 December 2005 - Emerson Process Management

Emerson Process Management announced today that Progress Energy is replacing the legacy controls on all four units of its 2,462-megawatt Roxboro Steam Plant with Emerson's Ovation expert control system. The multi-year project, which is being coordinated and supervised by Emerson's Power & Water Solutions industry center, began with installation of Unit 2 controls in April 2005, and continues as Ovation controls are installed at the plant's remaining three units as part of Progress Energy's adoption of a centralized, integrated control strategy for Roxboro, one of the largest power plants in the United States.

Although in place only a few months, Ovation's coordinated control schemes have helped Unit 2 improve ramp rates by 3 percent – from 91 percent in 2004 to 94 percent to date in 2005. In addition, Ovation's tighter control strategies have helped improve Unit 2 superheat temperature by +/- 5 degrees Fahrenheit regulation during load ramps.

The Ovation system will also enable the Roxboro plant to maintain environmental excellence. The old unit control systems were at maximum capacity, prohibiting the addition of new controls for selective catalytic reduction and scrubber systems. Now, with the Ovation system in place, Roxboro Unit 2 has been able to integrate and start-up a recently added SCR system along with the plant controls. In addition, a flue gas desulphurization system using Foundation fieldbus will also seamlessly link to the Ovation controls. The digital bus technologies of Ovation systems, as part of Emerson's PlantWeb digital plant architecture, present further opportunities for operations improvement in Progress Energy's ongoing replacement of legacy controls.

The integrated Ovation control system is replacing distributed control systems that were data linked to a host of other PLC-based systems throughout the plant. The DCS systems and PLCs all used Genius I/O blocks for 20,000 remote I/O points. Due to a tight outage schedule and added costs, it was not feasible to replace the existing Genius I/O with new modules.

Migrating the controls for the four-unit plant required Emerson to address a number of challenges, including supplying reliable and affordable redundant interfaces to the station's 2,700 Genius I/O blocks, furnishing operators with a centralized coordinated system for improving plant operation, installing the system within a 30-day outage schedule, and providing flexibility for adding new plant controls.

Emerson was the only vendor that provided a total modernization solution, including redundant interfaces to the plant's Genius I/O blocks. Linking the existing I/O to the Ovation system saved considerable construction and startup resources, as well as startup and checkout time. In fact, Emerson estimates that replacing the I/O would have added $3 million in hardware costs and $1 million in labor costs to the project. Furthermore, installing the new Ovation system for Unit 2 was accomplished within a 30-day scheduled outage, an impossible task if the I/O were to be totally replaced with new modules.

"We had specific requirements for interfacing to our existing I/O," said Steve Lowery, senior engineering technical support specialist, Roxboro Steam Plant. "Emerson was the only vendor that provided a total solution that met not only our interface specifications, but all our process control goals."

The Ovation interface to the Genius I/O is a bus master for up to 29 I/O blocks that exchanges point information with the Ovation controller. This interface provides seamless, full integration of all remote I/O with the Ovation network. The Ovation Developer Studio incorporates an interface Explorer tool that allows complete configuration of the Genius modules once they have been initialized with communications baud rates and addresses through a hand-held device. Ovation point tags are directly assigned to a channel on a Genius I/O block, which eliminates the need for register mapping.

"Without Emerson's integrated solution, each PLC I/O block would have had to be individually configured by someone onsite. Now, with the Developer Studio integrated tools, we are able to save considerable time by reconfiguring all the I/O blocks from one workstation," said Lowery. "What could have taken hours now only takes minutes through an automatic download from the Ovation system."

"By offering a solution that seamlessly integrated their existing I/O, Emerson allowed Progress Energy to take advantage of the latest technologies while still maintaining their existing investment," explained Bob Yeager, president of Emerson Power & Water Solutions. "Furthermore, this project illustrates the types of performance improvements utilities have come to expect when they adopt an integrated control strategy based on Ovation technology."

http://www.emersonprocess.com

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