By Johel Comas and Rob Barden
Platte River Power Authority Rawhide Energy Station Unit 1 is a 280 NET MW load unit that in 2016 had a capacity factor of 91.57 percent, the third highest for comparably sized US coal plants. However, such high performance does have a downside — there is very little opportunity for plant operators to gain much-needed experience in efficiently executing startups/shutdowns and confidently managing upset conditions.
Half of the Rawhide Unit 1 operators have less than a few years of experience, and a notable portion of their experienced operators will retire in coming years. When new plant controls were recently installed, the plant knew that to attain true operational excellence from their operators they needed to commit to a formal training and certification program, which in Rawhide’s case meant using a high-fidelity simulator.
Rawhide’s previous experience with simulation proved disappointing in that neither engineering nor operations took full ownership, which resulted in the simulator becoming outdated and unused. This time around, they were determined to chart a different course to extract the most value they could from it. Rawhide chose simulation technology that would not only retain its value as a training tool for the operations staff, giving them a safe environment in which to become adept at handling complex operating scenarios, but could also be kept up to date with industry standards and used by the engineering staff for control logic testing, patch verification and continuous improvement of plant operating procedures.
In less than four months, Rawhide will have conducted over 400 man-hours of operator training and is already seeing significant benefits, including a 44 percent reduction in startup and shutdown time and related fuel usage. Rawhide discusses the value of the simulator from both an operation and an engineering perspective and how it is helping to drive consistency, cultural change and continuous operational improvement.
Rawhide Unit 1 is a 280 NMW load unit that in 2016 had a capacity factor of 91.57 percent, the third highest for comparably sized US coal plants. Headquartered in Fort Collins, Colorado, Platte River Power Authority (PRPA) has long been a proponent of using simulators for training both experienced and inexperienced operators.
Their previous experience with simulation, however, proved disappointing in that neither engineering nor operations took full ownership of the simulator, resulting in it not getting the attention and maintenance required to function properly or be used effectively.
Over the past several years, Rawhide Energy Station has been seeing a relatively high turnover of operations personnel. Half of the Rawhide Unit 1 operators have less than a few years of experience, and a notable portion of their experienced operators will retire in coming years. While good news on almost any other front, the fact that Rawhide Unit 1 runs continuously with very few maintenance issues was a disadvantage to them in terms of operator training. On the positive side, the unit recently completed a run time of 393 days without any forced or planned outages. On the downside, operations personnel were not getting much opportunity to refresh/hone their skills or gain much-needed experience in efficiently executing startups/shutdowns and confidently managing upset conditions. In fact, PRPA had noticed that startups and shutdown times were getting longer and were often inconsistent.
All of this, coupled with the recent change out of their Foxboro controls to Emerson’s Ovation system, convinced plant management that to attain true operational excellence they needed to commit to a formal training and certification program based on high-fidelity simulation. They wanted a simulator that would not only retain its value as a training tool for the operations staff, giving them a safe environment in which to become adept at handling complex operating scenarios, but one that could also be easily maintained and used by engineering staff for control logic testing, patch verification and continuous improvement of plant operating procedures.
Rawhide chose Emerson’s Ovation embedded simulation technology in which the high-fidelity plant models are built with and maintained using the same familiar engineering tools as the DCS, something that would allow Rawhide to more easily maintain the simulator, keeping it current with control logic and other plant changes.
At this point, the project goals were quite clear for PRPA: Implement a new high-fidelity simulator that could a) be used by the operations department to train control room and FGD operators, and b) be used by the engineering and I&E departments for control logic testing, patch verification and development of other skills.
PRPA’s vision was to use the simulator to drive cultural change, consistency in plant operations, and continuous operational improvement.
1) The new simulator would need to be on site and ready to use within 12 months.
2) The simulator training room would need to be located as close to the real control room as possible; however, it would not fully replicate the main control room due to cost considerations and the need to make efficient use of the newly built training room.
3) The new simulator models would need to fully replicate the main plant and FGD controls not just for training purposes, but so that plant engineers could also use it to fully test logic, graphics, and patches prior to loading them into the real Ovation DCS environment.
Rawhide engineers also wanted to be sure that they’d have the capability to make simulator tuning and algorithm modifications themselves so that they could avoid the mistakes of the past and keep the simulator current with the real plant, thereby retaining the value of their investment over the long term.
To ensure a successful project, PRPA and Emerson had to work collaboratively, as a single team, toward these common goals and objectives.
One of the most important factors in the success of the project was having a single, Emerson project manager to oversee the entire project from start to finish – from initial design, to testing, to installation and commissioning. After an initial team meeting held at the Rawhide Energy Station, Emerson began work on creating the high-fidelity models for the unit. PRPA provided Emerson with a lot of information including newly written startup and shutdown procedures to guide them in developing the simulator. Four months later, PRPA attended the first of five two-week verification meetings at Emerson headquarters in Pittsburgh, PA. PRPA opted to travel to all verification and factory acceptance test meetings rather than conduct them virtually because they felt this option provided them with the best environment to work closely with Emerson and develop a solid, long-term working relationship.
Throughout the process, PRPA brought different operations crews to the verification meetings, giving everyone an opportunity to contribute and “own” part of this important project. The rotations were scheduled during a crew’s relief week, maximizing their effectiveness while minimizing disruption to normal work schedules.
The initial plan was for PRPA to make four, two-week trips, but some unforeseen issues required them to schedule an additional two-week trip. Once this bump in the road had been resolved, the process moved quickly and the Factory Acceptance Test went smoothly. The new simulator was shipped to Rawhide in October 2016 and the Site Acceptance Test was completed just prior to Thanksgiving.
“In a quest for continuous improvement, Rawhide plans to continue using the simulator to refine operating procedures and further reduce startup and shutdown time.”
Benefits of Embedded Simulation
Since installation of the new simulator, Rawhide’s engineering department has been able to do exactly what it wanted – test all major logic changes without risk to the actual plant, watching the outcomes as they play out in real-time in the simulated environment. This capability has greatly enhanced their efficiency and contributed to the overall success of the department — not only are they testing logic changes, but they are also able to confidently load Microsoft and Ovation security patches on the real system after testing them in the simulated environment, making it easier and less stressful to keep the control system up to date. The engineering department has also used the simulator as a test bed when making global changes to graphic macros and overviews, saving considerable time and stress while eliminating the risk of a unit trip.
Platte River Power Authority has been quite pleased with the impact that the new high-fidelity simulator has had on their training program. In the first four months, operations completed over 400 man-hours of simulator training and have already seen significant benefits, including a 44% reduction in the time operators require to perform plant startup and shutdown scenarios.
In a quest for continuous improvement, Rawhide plans to continue using the simulator to refine operating procedures and further reduce startup and shutdown times. Rawhide operators are now able to experience operating conditions and malfunctions that most of them had not previously seen.
With the high-fidelity simulator being used as a cross-functional tool, Rawhide is in the enviable position of being able to test logic changes, install patches and determine graphics best practices prior to implementing them on the “real” Ovation DCS. The ability to make changes in a controlled virtual environment without worrying about taking the unit off line is invaluable to PRPA as they continue to drive toward a culture of operational excellence at Rawhide Energy Station.