Power, control two different issues

Advanced control applications are not in widespread use in the power industry. Why?
Successful applications exist, but it takes work and education. You’ll need to study the technology and published experiences, work closely with and rely on technology vendors, and plan properly for success, short and long term.

At the last ISA Power Industry (POWID) conference this past June, Jacques Smuts of OptiControls presented some thought-provoking results from a survey on the requirements for implementing advanced control applications in the power industry.

The survey reported road blocks such as insufficient funding for advanced control projects, doubt about the existence of sufficiently proven technology, and shortage of adequately skilled personnel.

Barriers to implementing sequential automation applications included the lack of guidelines or published papers on the subject. Vendor incentive and configuration tools are also waning, the survey found.

“It’s interesting to see that the quality and volatility of operating procedures, availability and reliability of field instrumentation, increased cost of maintenance, and high operator skill level make implementing sequential automation projects less attractive, especially in the U.S.” Smuts said.

So what does the power industry need to make implementing advanced control applications an attractive option and a success?

Requirements for success
“If you want to do a sequential automation project, you’ll need management buy-in,” Smuts said. “You have to have an on-site champion during design and commissioning, and the design team needs to be multi-disciplined.”

Someone who understands what you can and can’t do with this sequential logic inside the DCS is critical to the success of the project. “Accurate, comprehensive, and stable operating procedures are a must,” he said. “If you don’t have the manpower, you can contract it from a system integrator company. But you have to be prepared to upgrade field instrumentation and automate hand valves.”

“Allow enough time for commissioning, and plan on increased maintenance,” he said.

The barriers to implementing automated control loop monitoring and tuning tools are complex, he said. “You’re competing with humans already doing the tasks manually, and automating it requires advanced knowledge and skills. You have to understand what the software is doing and interpret the results. It’s beyond an operator or junior technician to do that – it’s more of a job for a senior technician or engineer,” he said.
Cost justification is difficult as well, especially for loop monitoring. Where’s the return? “It could cost up to $40,000 to implement it. Network security issues are a problem, especially in nuclear plants. “If you can’t get data, the software doesn’t work, and you can’t just go connect software to nuclear equipment.”

“If you look at a typical refinery, they have teams of advanced control engineers. Their job is just to maintain the APC applications,” he said. “In the power industry we don’t have that. There aren’t specialists in APC at a site, sometimes not even in the entire company. As an industry, we’re short on APC-skilled people. Also, this technology is competing with advanced regulatory control (feedforward, cascade, etc.), which is already available in the DCS to help us control our complex plant. The incremental benefits are not always so obvious. There is a lot of uncertainty. How much will we get back on our investment?”

Requirements for success also include using the right APC technology. Model predictive control is mostly used for steam temperature control, neural networks for combustion control, and expert systems for smart sootblowing.

Rely on vendor or consultant expertise “because we don’t have the skills in the power industry,” he said.

“You will need additional instrumentation and will have to modify your DCS to accept these APC signals. The APC sends set points and biases down to your control loops in the DCS. So your DCS-based controls have to be in good shape as well.

Extensive training is required, and some of the tools are not user-friendly. You’ll need someone on site who’ll understand how to get APC back up and running. And you’ll have to train the operator on the workings of the new technology.

That’s where the onsite champion comes in – it could even be someone who oversees two or three sites. “The APC doesn’t have to run for the plant to run. The first time it makes a weird move, the operator turns it off. The champion has to ask why? And then train the operator or do whatever is necessary to get it turned back on. Otherwise, these systems will all get turned off.”

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