For utilities as well as process industries, OPC provides open connectivity through a series of specifications based on open standards, linking systems and devices from multiple vendors. OPC’s open communication architecture, focused on data access, provides information in a consistent manner to a variety of plant floor applications. Visibility of critical site system information, such as direct access to alarms, helps customers react quickly to avert potential system and equipment issues. Control systems from global automation supplier ABB leverage this standard interface when integrating with third-party systems and devices to deliver improved performance for its customers.

Western Kentucky Energy (WKE) generates electricity at four stations that it operates and maintains under a 25-year lease agreement with Big Rivers Electric Corp. WKE is a wholly owned subsidiary of E.ON U.S., Kentucky's primary energy services provider and one of the nation's largest, low-cost energy firms. Based in Louisville, E.ON U.S. is a diversified energy services company with businesses in power generation and project development; retail gas and electric products and utility services; and asset-based energy marketing.

WKE’s D.B. Wilson Station in Matanzas, Ky., began commercial operation in 1984 with one coal-fired generating unit for a station net generating capacity of 420,000 kilowatts. Its pollution control equipment includes a high-efficiency electrostatic precipitator, a scrubber that removes more than 90 percent of the sulfur dioxide from the flue gas, and a state-of-the-art selective catalytic reactor (installed in 2003) that removes more than 90 percent of the nitrous oxides from the flue gas. The plant has the versatility of both barge and truck fuel supply.

Efficient, cost-effective control of energy-generation and emissions management processes is critical to WKE.

OPC technology provides WKE with greater visibility of and access to key plant information, allowing the company to operate more quickly and efficiently. It connects a variety of programmable logic controllers (PLCs) on WKE’s Flue Gas Desulfurization (scrubbers) system to the ABB Harmony control system. WKE also uses the OPC Server to connect to a third-party historian for archiving purposes.

Using OPC, WKE transfers alarming information and brings plant data and equipment status to operators for viewing and response. Alarming is displayed on a main alarm list, which includes primarily outlying installations, such as motor and pump bearings and winding temperatures, as well as flows and pressures on cooling towers, water treatment and coal-handling processes throughout the Wilson plant.

Before all Wilson plant systems were linked with OPC, WKE’s PLC alarm list was located physically behind the operator. Other data—including temperature points on circulating water at the cooling towers and on the condenser under the Wilson turbine, as well asdata on fan control—was only available in the PLCs, and not accessible from other plant systems.

OPC has enabled all necessary information from many different screens and the PLC alarm list to be visible in front of the operator. This has been a great time- and cost-saver for WKE.

The scrubber at the Wilson facility is horizontal, which means that if slurry is not circulating, gas temperatures will melt the mist eliminator panels, rendering the module unusable. In one instance, pumps tripped on one such module; OPC connectivity made the alarm from the PLC visible on the ABB Harmony control system. The operator was instantly aware of and able to remedy the situation by getting the pumps restarted. This ability to reduce the time needed for decision and action in this situation saved WKE approximately $50,000 in potential equipment damage.

ABB provides a comprehensive range of control system products and solutions that enable utility and industry customers to improve their overall productivity. To find out more, visit www.abb.com/controlsystems.