Instrumentation & Controls

Distributed control systems are powerful assets for new and modernized power plants. Thanks to three product generations of technology innovations, these systems now provide new benefits — including improved O&M efficiency, greater plant design flexibility, and improved process control and asset reliability — that help competitive plants advance in the game.

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?

Wireless technology is a mostly untapped resource in the power generation industry that can have a significant impact on the way business is done. It enables a greater degree of connectivity among devices for enhanced monitoring and asset utilization and has led to the development of new applications that improve productivity, uptime, and overall business performance.

Modern wireless systems improve productivity, monitoring activities, and safety at power plants by enabling the right people to be at the right place at the right time. Wireless technology can put hard-to-access process and asset information at your fingertips, wherever you are, to enable more accurate and timely decisions.

If the rotating equipment and boiler are a plant’s brawn, then a control system that efficiently integrates myriad plant functions is its brains. Luckily, in a power plant, we can perform a brain transplant when the control system becomes unreliable or too costly to maintain. But first, you have to justify that surgery.

In 2005, Jersey Central Power & Light (JCP&L), a subsidiary of Akron, Ohio – based FirstEnergy Corp., initiated a project to identify protection system improvements that could be made to proactively combat wind- and lightning-related weather events that create sustained power outages (Figure 2). JCP&L determined that these changes had the potential to improve the […]

Entergy christened its Performance Monitoring and Diagnostic Center several years ago to leverage the expertise of its most senior operators and technicians across the company’s entire fleet of plants. The center also makes use of advanced software tools that increase plant availability and reliability by identifying faults before they become major, unplanned outages. The center paid for itself for years to come with a single “big catch” last year.

Tackling substandard water sources / Control abrasive wear in scrubber piping / Sensors and final control elements

Documenting changes to the distributed control system and other digital plant applications should be considered a critical element of managing risk—and of safe, efficient daily operations and maintenance. Coming up with a practical configuration management approach, though, isn’t easy.

Control systems used by utilities and other operators of America’s industrial infrastructure increasingly rely on an Internet connection that makes them as vulnerable to hackers as any computer or network. One reason many utility control systems are vulnerable is that, unlike your ISP’s systems, they don’t record an audit trail that reveals the source of the attack.

Burning spot market fuels can reduce plant fuel costs, but it can also introduce unexpected operational problems throughout the boiler island. Orlando Utilities Commission’s Stanton Energy Center optimized its Unit 2 combustion system and improved O&M practices as part of a project to increase the unit’s fuel flexibility without degrading reliability or heat rate. OUC’s attitude: If you can measure it, you can manage it.

The ability to detect contaminated feedwater or steam before it can corrode the internals of a turbine or HRSG and cause a forced outage is worth millions. One knock against cation conductivity monitoring—still the most common technique for the early detection of contamination—is the difficulty of interpreting conductivity readings when the plant’s makeup contains significant levels of organics or CO₂. Here are the pros and cons of cation conductivity monitoriting and some alternative monitoring methods.

Modern predictive maintenance systems can monitor the health of most plant equipment. By sorting through the wealth of information those systems deliver, operators can discern important trends, including the early signs of a system or component failure.

Selecting the right turbine(s) for a specific power project is a complex process that poses two challenges. One is understanding which field experience cited by suppliers represents proven technology; the other is evaluating whether a turbine upgrade represents an evolutionary change or a revolutionary transformation that warrants further study before deploying it in the field. Here‘s how a leading EPC contractor makes technology-neutral equipment selection decisions on behalf of its customers.

Managing ongoing threats to power plants’ digital, telecommunications, monitoring, control, and automation systems is no longer just a good idea. It’s an essential element of superior plant operations and now a regulatory requirement as well, thanks to new critical infrastructure protection standards recently approved by FERC.

Lower Colorado River Authority recently put two separate plants at its Lost Pines Power Park under one functional management system. The project has already deployed a layered wireless infrastructure that allows the two plants to communicate at a fraction of the cost of a wired solution while providing a platform for optimizing work processes and reducing operating costs. What’s not to like?

Carbon dioxide emissions aren’t yet regulated by the EPA, but it’s likely they will be soon. There are many technically feasible, but as-yet-undemonstrated ways to reduce the considerable carbon footprint of any coal-fired plant, whether it uses conventional or unconventional technology. One promising approach to removing CO2 from a plant’s flue gas uses chilled ammonium bicarbonate to drive the separation process.

The dearth of commercial operating experience for advanced coal-fired facilities is forcing their early adopters and builders to use long development cycles and pay high costs for unique engineering design studies. A broad-based industry collaborative effort fostered by EPRI to address this issue is beginning to show results.

All fossil fuels carry some risk with their reward of an energy density that’s sufficient for producing electricity economically. For coal and natural gas, that threat is a fire or explosion. However, the risk of an explosion isn’t limited to gas-fired plants. Gas poses a threat to any plant that uses the fuel, even in small quantities for heating. Here’s an overview of what you should be doing to keep gas pipelines from corroding and exploding.

Last year, San Diego Gas & Electric tapped Boston-based EnerNOC Inc. to aggregate 25 MW of backup generators throughout SDG&E’s service area to relieve the grid when it’s stressed by peak demand for electricity. By combining stringent environmental controls with field-proven expertise managing distributed assets, EnerNOC has helped to improve grid stability in Southern California.

Single-window control of CHP plant’s energy converters / Safety stuffers entertain as they inform / Doubling up for a heavy load

The NERC auditors are coming / Winning encore for on-line pH monitoring / Using baloons as temporary barriers / How data logging can cut power bills

To make the most of their digital devices and enable the sharing of data by different departments, new and old plants alike need a reliable digital data infrastructure.

Over the past few years, U.S. nuclear power plants have begun replacing their obsolete analog control systems with digital control systems. Many of these projects have been completed successfully, yielding a tidy return on investment in the form of increased generation. However, some have encountered difficulties, which resulted in cost overruns and schedule delays. This minority of projects may have eroded the industry’s confidence in digital upgrade projects, but a well-run project is still one of your best options for squeezing the last drop of performance out of your plant.

How do you know if a pressure transmitter is giving poor results? Unless the transmitter actually fails, most operators won’t notice a very slow loss in accuracy or response time. Fortunately, the noise analysis technique can identify such changes before they cause a problem. The technique has been used to effectively measure the dynamic response of nuclear power plant pressure sensors and their associated sensing lines. It also can be applied to any plant that relies on accurate instrumentation for control and monitoring plant performance.

The average pulverized coal–fired coal plant is more than 30 years old and has a heat rate in the neighborhood of 10,300 Btu/kWh operating with an "off-design" coal. Add a high load factor (or increased cycling service), squeezed maintenance budgets, reduced plant staff, and increased time between overhauls to meet the plant’s pro forma, and you’ve got major stress. Fortunately, there is a way to come in under your NOx budget and lower the stress. Breathe deeply and read carefully.

Air and steam sootblowers have been the power industry’s solution to the slagging and fouling of boiler convective passes caused by flyash and combustion products. Manual cleaning systems have been superseded by computers and neural nets, but the basic cleaning apparatus remained unchanged—until now. Say hello to detonation waves. They can knock those deposits loose while markedly improving boiler heat transfer efficiency.

Tubing manufacturers have many alternatives for manufacturing and testing stainless steel tubing for feedwater heater and condenser applications. ASTM specifications are fairly generic in nature and only specify the minimum tube design and testing requirements—which may not be sufficient to provide the appropriate quality for a critical power plant application. To make the right material selections, it’s helpful to understand how welded stainless steel tubing is manufactured and its quality is checked.

Ongoing research into experience with plant- and fleet-level software reveals that these applications work side by side but do not necessarily function as an integrated “knowledge management” system. On the supplier side, the industry continues to be fragmented, with individual programs governing a narrow part of the overall plant.

PG&E mounts tidal power project / GE F-class turbine breaks record / Iowa welcomes ethanol-fed hog / NYPA upgrades pumped-storage plant / Bush blesses Browns Ferry 1 restart / Shearon Harris looks to live on / Nevada bets on solar thermal / Climate models questioned / POWER digest