Updating control and automation systems at old coal-fired plants

Paul Boughton

Operated by Korea Midland Power Company (KOMIPO), Boryeong is the biggest thermal power station complex in the country. With a generating capacity of 4800MW, it accounts for 7.4percent of Korea’s total electrical output.

Construction of the two original coal-fired units began in 1979 and was completed four years later. In 1983 and 1984, units 3, 4, 5 and 6 were added – bringing capacity up to 3000MW. The addition of a 1800MW combined cycle plant in 2002 brought the complex up to today's overall capacity.

KOMIPO has now awarded Emerson Process Management a contract to replace the existing controls on the two original coal-fired units with its PlantWeb digital plant architecture.

Previously, the two units each utilised multiple control systems – analogue Toshiba turbine controls and a Bailey820 analogue system that controlled each unit’s Babcock & Wilcox boiler and balance of plant processes.

Burner management

Installation of Emerson’s Ovation expert control system will offer an integrated control solution for the nearly 25-year-old units. The Ovation system, a key technology that powers PlantWeb architecture, will monitor and control all major equipment, including the boiler, turbine and boiler feedwater pump turbine, as well as the burner management system and balance of plant processes.

“This project, in which separate islands of automation are replaced with a tightly integrated control system, is a model for how to modernise controls of an existing power generating facility,” said Bob Yeager, president of the power and water solutions division of Emerson.

“By adopting an integrated control strategy based on our PlantWeb architecture and Ovation technology, we expect Boryeong units 1 and 2 to achieve greater operational efficiency and enhanced plant performance – all of which will help KOMIPO best serve the burgeoning electricity needs of this region,” he added.

Installing the integrated Ovation solution will unify boiler and turbine operations, thereby translating into a number of significant operational benefits. For example, fully co-ordinated boiler and turbine control not only enhances unit-wide compatibility, but also contributes to improved unit stability, responsiveness and thermal efficiencies; tighter overall control of plant operations; and a more streamlined view of key plant and turbine parameters.

In all, Emerson’s Ovation system will manage 12000I/O points at each unit. For additional efficiency, operators will be able to monitor and control operations of units 1 and 2 from a central control room.

Other components of Emerson’s automation solution include AMS Suite: Intelligent Device Manager and intelligent field devices, including Fisher I/P positioners (57perunit) and displacement level transmitters (24perunit), as well as Rosemount temperature transmitters (556perunit), differential pressure transmitters (11perunit), differential level transmitters (18perunit) and pressure transmitters (fiveperunit).

Emerson’s power and water solutions industry centre will engineer, install and supervise the project. Both retrofitted units are expected to be operational in 2009.
“Emerson has demonstrated their knowledge of large control system retrofit projects in general, as well as an understanding of our objectives for this modernisation project, in particular,” said JungHyun Park, plant management team manager, power generation department, KOMIPO. “Their ability to provide a comprehensive, integrated automation solution that takes advantage of the latest technologies was exactly what we were looking for in an automation supplier for this project.”

Under a separate contract, Emerson is migrating its previous-generation WDPF control system to the Ovation system for balance-of-plant processes at Boryeong units 4 and 6. The unit 4 project is complete, while the migration for unit 6 is currently underway.

Another company taking the PlantWeb/Ovation route is Hastings Utilities in Nebraska. The expert control system is to be used a new 220MW coal-fired power plant being built at the Whelan Energy Centre in Nebraska.

The plant will be owned by Public Power Generation Agency (PPGA) which consists of five public power entities: Grand Island Utilities, Hastings Utilities, Heartland Consumers Power District, Municipal Energy Agency of Nebraska (MEAN), and Nebraska City Utilities. Black & Veatch. is the engineering firm for the project.
The new unit, expected to begin commercial operation in 2011, joins an existing 77MW coal-fired plant that has been in service at the Whelan Energy Centre since 1981.

“Nebraska and the Midwest region are facing an increased demand for electricity,” said Allen Meyer, PPGA project construction manager. “The additional megawatts produced by this plant will help PPGA member companies meet the needs of their customers and, therefore, have a positive impact on the region.”

The Ovation system will manage a total of 4500I/O points. It will monitor and control the unit’s boiler, as well as the burner management system, flue gas desulphurisation system and balance of plant processes. In addition to the Ovation system, Emerson will also provide AMSTM Suite: Intelligent Device Manager, as well as 200 Rosemount3051T pressure transmitters and 74 Rosemount3051C differential pressure transmitters.

Emerson has a longstanding relationship with Hastings Utilities: not only does the utility's North Denver generating station also rely on Ovation technology, Emerson’s legacy 7300 controls were also the original controls for Whelan unit 1. In fact, in a project completed in November 2007, Whelan Energy Centre's boiler and turbine controls were replaced with Emerson’s Ovation system.

According to Emerson, aligning a unit’s boiler and turbine control is advantageous, translating into:

unit-wide compatibility; improved unit stability, responsiveness and thermal efficiencies; tighter overall control of plant operations; and a concise view of key plant and turbine parameters.

Demand response infrastructure

Based in Baltimore, Maryland, BGE is the state’s largest gas and electricity utility. It currently has over 1.2m electricity customers and 640000 natural gas customers.
The company has selected Honeywell to provide marketing, installation and call centre support for the its residential demand response infrastructure (DRI) programme.

The new Honeywell UtilityPRO thermostat also will be a key incentive for the programme, which will help cut energy costs for participating customers and give the utility greater control of peak consumption on hot days when air conditioning use strains the power grid.

BGE and Honeywell expect to enroll an estimated 420000 customers in the programme, almost 50percent of the utility’s residential customer base with central air conditioning. This is 20-30percent above typical demand response participation, making this one of the US’s largest and most significant residential programmes to date. BGE estimates its DRI programme will reduce over 600MW of peak energy use by 2012, equivalent to the generation capacity of a small- to mid-sized power plant.

Wireless technology

BGE customers who enroll in the programme can receive a free, professionally installed Honeywell UtilityPRO – a digital touchscreen thermostat designed specifically for demand response programmes. This features wireless technology that lets BGE communicate with the thermostats, and cycle air conditioners on and off for brief intervals.

The change in temperature in the home is hardly noticeable, and the cycling helps limit energy consumption on the hottest spring and summer days.
Built on the same platform as Honeywell VisionPRO, the best-selling, award-winning programmable thermostat (Fig.1), UtilityPRO features intuitive touchscreen interaction and a large, easy-to-read backlit display. It also offers online programming capabilities so users can adjust settings via the Internet.

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