Great River Energy (GRE) is a not-for-profit electric cooperative that generates and transmits power for 28 member cooperatives throughout southern, central, and northern Minnesota and northwestern Wisconsin. With a generating capacity of more than 1,100 MW, Coal Creek Station in Underwood, N.D., is the cooperative’s largest power plant.
The plant operates two boilers fueled by lignite coal, which is supplied by nearby Falkirk Mine. Lignite is a softer coal that contains higher water content than other types of coal. GRE uses a patented coal-refining process called DryFining, which utilizes waste heat from the plant to dry and refine the coal, making it burn cleaner and more efficiently.
Recently, GRE upgraded the consoles in the control room at Coal Creek Station to improve ergonomics for workers monitoring plant operations (Figure 1). The primary reason for the upgrade was to improve the operators’ sightlines to the top row of monitors in the control room. In order to see the top monitors, operators were tilting their heads too far back and experiencing eyestrain from trying to focus on information on the screens.
|1. Coal Creek Station distributed control system console. Courtesy: Winsted Corp.|
GRE worked with Winsted Corp. to design and install new ergonomic consoles. In order to eliminate any need to drill holes in the floor or move wires or cabling, the new consoles needed to fit the existing footprint and floor penetrations.
“The control room upgrade was really a team effort between our operations, electrical and instrumentation, IT, safety and management staff and Winsted Custom Division along with their installation team,” said Mark Baisch, control room operator at Coal Creek Station. Together, Winsted and GRE created a design that includes three custom Matrix-Evo consoles in a horseshoe formation.
Two of the consoles sit back-to-back, with each controlling one of the two power generation units (Figure 2). They are laid out identically, so regardless of which unit an operator is controlling, the process is the same. For instance, the turbine generator control is always on the left no matter which console you are facing. Each of these consoles has five monitors mounted to it, plus the operator’s local area network computer.
|2. Coal Creek Station control room. Courtesy: Winsted Corp.|
The third console controls the coal-refining process. It’s a bit smaller than the other consoles and has only four stations, but otherwise it houses the same equipment. The reason for this is that the control system is operator-based, which means operators can run any of the controls from any of the three workstations, depending on how they log in.
More Than Just Aesthetics
To improve sightlines and reduce physical stress to operators, Winsted followed ergonomic standards for control room design outlined in ISO 1106. The monitors on each of the consoles are mounted several inches below the work surface using a unique, track-style mounting system. The system uses an integrated horizontal aluminum track, which enables easy adjustment of post-mounted brackets.
While the vast majority of the control system is digital and controlled via computer, there are a number of hard panel switches mounted to the console that must also be visible and accessible. “The new consoles meet the operators’ needs,” said Baisch. “They solved the neck strain issues and improved the visibility of the top monitors.”
Additional console features included metal base cabinets and Corian work surfaces to reduce combustibles in the control room for safety and insurance reasons. Winsted also incorporated some slat wall panels that allowed file management systems for paperwork, books, and a phone tray to be kept off the work surface. The new console also maintained the Americans with Disabilities Act (ADA) requirements, allowing enough space for a wheelchair or other assistive device to roll through.
In addition to ergonomic and ADA considerations, it was important that the new consoles be scalable to allow for future upgrades to the control room. The track mounting system supports a wide variety of monitor arrays. This will allow GRE to eventually replace the existing 20-inch monitors (4:3 aspect ratio) with today’s more common 22-inch model (16:9 aspect ratio) without having to make any alterations to the console.
From design to installation, the console upgrade in the control room at Coal Creek Station was a success. Winsted worked closely with GRE to complete the installations during plant outages, so disruption to plant operations was never a concern. Most importantly, the consoles provided vastly improved ergonomics for control room operators, enabling them to do their jobs more comfortably and with greater efficiency.
—Rusty Hellen, senior designer for Winsted Custom Division ([email protected]).