February 1, 2009

Power Plant Automation: Where We Are and Where We’re Headed

Roger A. Leimbach,

Over the past decade, power plant control systems have evolved from DCS-centered platforms with proprietary software, to open systems using industry standard hardware and software, and then to totally integrated plant automation systems with almost unlimited connectivity and the ability to interrogate field instruments from many different manufacturers. What’s next?

Today’s power plant control room is evolving into an almost office-like setting, typically quiet and with few staff. Gone are the large boiler-turbine generator (BTG) boards and vertical panels populated with indicators and strip chart recorders. Also gone are the numerous manual/auto control stations that allowed plant operators to individually access final control elements.

New technology has significantly changed the purpose of the control room. No longer a place where operators control, it is now just one of several portals for an integrated team of experts with the common objective of maximizing the value of the plant’s assets (Figure 1).

1.Control rooms are evolving. Gone are the large boiler-turbine gauge panel boards, the walls of instruments, and strip chart recorders. Decisions are made by a team of experts, most of whom will not be on site. Today’s automation systems include portals that allow people from all over the world to access information in real time. Courtesy: Metso Automation USA Inc.

Over the past 10 years automation platforms have progressed from primarily proprietary hardware and software designs to systems that maximize the use of industry standard hardware and software. The Microsoft invasion has eclipsed most distributed control system (DCS) platforms. In addition, the hardware, including controllers and I/O modules, has gotten smaller while its computing power has increased geometrically.

Automation systems are also fast becoming commodities, yet generating companies (gencos) have not relaxed their requirements for a rugged design that includes components and modules that meet high standards for reliability. The typical power plant automation system is populated with rugged I/O modules that meet strict standards for isolation, surge-withstand capability, and environmental specifications. Remote terminations external to the I/O modules are still prevalent in many power plant installations and will surely be with us in the future.

Off-the-shelf hardware solutions have resulted in lower prices for hardware such as I/O modules and even controllers. Studies have shown that the value of hardware included in system shipments continues to fall while the value of software applications continues to rise. However, just because the technology is available doesn’t necessarily mean the technology is appropriate at any price.

At the same time, several different computer bus architectures have evolved, and no single one is more accepted than the others: Fast Switched Ethernet, Foundation Fieldbus, Profibus, ASI, DeviceNet, and others have all found wide acceptance by vendors and users alike. However, most automation system suppliers distinguish themselves with applications and services that are specific to an industry. The ability to supply products and services that enhance operations — increasing availability, increasing efficiency, and controlling emissions — is a major requirement of the power industry today, and its importance will grow in the future.

Beyond cheap computing and advanced software applications, an automation system must be designed to optimize the economics of plant assets. Deregulation has required greater awareness of optimizing operations. Maximizing availability, efficiency, and safety are crucial roles of an automation system. Furthermore, monitoring, reporting, and controlling emissions have been elevated, in some cases to the highest corporate level, largely because of regulatory scrutiny. In sum, the current operational environment is far more sophisticated than at any time before, yet we’ve just barely scratched the surface of automation system capabilities.