By Lindsay Morris, Associate Editor
Where would the world be without wireless? We rely on hand-held wireless devices to keep us closer to family and up-to-date with anything from the stock market to movie times. In the power industry, wireless can be used to improve communications, lower costs, increase security and allow access to information previously not attainable.
|The Verizon Wireless Network Operations Center monitors cell sites and switches across affected areas. Photo courtesy Verizon Wireless.|
A wireless network installation at a power plant entails more than just the hand-held or Internet connection typical to the mainstream. Modern wireless networks are constructed with a series of wireless access points, or radio nodes, installed at strategic areas of interest within the plant.
|Hand-held programs like AspenTech's mobile application allow power plant managers to access plant information from any location. Photo courtesy AspenTech.|
A wireless network can consist of anything from a network of transmitters monitoring a single application to a full-scale network of wireless devices scattered across an entire facility to control multiple applications, including monitoring and supervisory control. The wireless network is typically accessible though handheld, mobile devices. This allows personnel to interact directly from a handheld device while performing maintenance rounds, data collection and inspection.
Power Plant Applications
A wireless network can have numerous applications in a traditional power plant setting. Wireless allows access to remote devices and opens up blind spots in a facility where measurements are not taken as often as they should be. By adopting wireless, operators, maintenance, IT personnel and plant management gain convenient access to information previously unattainable. For example, wireless technology can provide a cost-effective method for measuring water quality or corrosion in tanks and pipes.
"Steam traps, remote settling ponds, chemical treatment areas, storage areas; wireless affords the opportunity to glean measurements from areas like these that are difficult to monitor or not typically monitored," said Ray Rogowski, global marketing director for Honeywell's wireless business. This access can yield information that improves plant safety, reliability or efficiency.
|A BS&B Safety Systems' wireless transmitter (lower left) communicates to a receiver a quarter mile away. Photo courtesy BS&B Safety Systems.|
By conducting remote analytical pH readings, plant operators can monitor water quality, thereby eliminating the need to sift through maintenance logs and corrosion data. With wireless, all of the information is aggregated into a single set of data.
Wireless could also be used during the upgrade of equipment such as coal conveyors. Some conveyers are controlled by variable frequency drives (VFDs) that might be remotely located and require new cable runs for analog control and feedback signals or communication, said Mitch Dolenic, electronics sales manager for BS&B Safety Systems. Many coal conveyors are controlled by devices that apply either 100 percent power or 0 percent power, essentially a start/stop control. Potential benefits exist by upgrading these types of control to a VFD that incorporates wireless and allows for a range of speed control (0 through 100 percent, for example). This permits users to run a conveyor at half speed, ramp-up, ramp-down and vary speed based on load and demand. The power savings associated with this type of control can have significant paybacks, Dolenic said.
When upgrading to VFDs, the control signal wires usually used for contactors cannot be used because of extensive cabling requirements. Therefore, a power plant could use a wireless system to transfer analog data "control signals" between the VFDs and a centralized control system. This helps reduce project capital expense and also start-up time, Dolenic said.
Other applications for wireless include data sensing and collection on remote transformer stations, chimney stacks, cooling towers, boiler systems and steam traps and on rotating equipment like milling machines, kilns and turbines.
"Wireless technology can make turbine testing much more efficient since wireless can be easily incorporated for temporary and permanent measurements," said Mike Wojcik, director of enterprise data sales for Verizon Wireless.
Outside the power plant, wireless can be used in transmission substations to connect transmission lines, sometimes of the same voltage, and run them either to more or fewer lines. In more complicated scenarios, wireless solutions can connect lines of different voltages and convert them to the same voltage. Wireless can also be used at distribution substations to decrease the voltage transmitted from the main distribution station, enabling the power to be distributed to end-users.
Wireless devices are found at wind farms where they help to determine wind speed and kilowatt hour production. Wireless battery-operated devices provide the opportunity to gather data and effectively calculate production. Additionally, wireless has become a regular feature at some solar energy facilities, especially those in desert locations. With many hand-held wireless devices for solar and wind farms, plant managers are able to monitor the plant remotely. This saves on costs and time, since most solar and wind farms are in remote locations.
"Key managers have less time to collect data and make insightful analysis and decisions," said Mark Gallant, director of industry marketing at AspenTech. "Less time means they have to work smarter, with real-time access to information to maintain and improve a plant's operations."
Thanks to wireless technology, minor disturbances can be handled before turning into a more serious interruption. Whereas users previously needed to be in the control room or in front of a monitor to track and manage plant performance, mobile applications and wireless devices make information available regardless of a user's location. "Adopters of wireless technology have reported this is helping them to avoid de-rating the unit and in some reported cases a trip event," Gallant said.
Wireless video systems can also be installed to guard the facility in addition to keeping an eye on processes. Verizon Wireless recently deployed IPVision's virtual video recorder solution at several power plants operated by one utility. The installation has been successful in securely monitoring the facility and reduced IT costs associated with traditional surveillance systems, said Wojcik.
Sky's the Limit
The realm of wireless can be as limited or as expansive as plant management desires. One wireless option for the power industry is to leverage public cellular broadband solutions enabled by Tier 1 and Tier 2 Mobile Network Operators (MNOs) or Mobile Virtual Network Operators (MVNOs). While the use of private radio networks or other unlicensed short-range technologies are currently more prevalent in power plant environments, many power and energy providers are realizing the cost, scalability and security advantages offered by public cellular network operators. By leveraging 2G, 3G and now 4G modules, gateways and routers as communications equipment, power providers can monitor their equipment from any location with an Internet connection by connecting their existing SCADA systems.
Public networks are available from MNOs like Verizon Wireless, AT&T, Sprint, Telus, Vodafone and Tier 2 and MVNOs like Cellular South, KORE networks and several other firms. Certified communications hardware is available from companies like Sierra Wireless.
A different type of wireless installation – sometimes referred to as "short-range" wireless or "local data collection" – is a wireless instrumentation backhaul. These installations typically run on WirelessHART or ISA100 networks. Short-range wireless includes the actual control and instrumentation installation at a power plant, offered by companies such as Emerson, Honeywell, BS&B Safety Systems and Verizon Wireless.
A third category of wireless installations is known as IEEE 802.15.4 wireless sensor networks that are condition-based maintenance (CBM). These systems are strictly used for predictive maintenance, prognostic health management or monitoring (PHM), and asset health management or monitoring. These installations are conducted by companies such as Sporian.
Just as cell phones have improved global communication by connecting millions of people, industrial wireless connects thousands of instruments together, allowing for a more productive work environment and easy access to data from anywhere in the world.
Wireless vs. Fiber Optics
Over the years, optical fibers replaced copper wire communications in core networks. Now, wireless technology is gradually replacing fiber optics. In general, fiber optic networks have been plagued with a stigma of being labor intensive and an expensive approach to connecting equipment. However, if a large bandwidth and an extremely high connection are needed, then "fiber optics is your only route," Dolenic said.
|Wireless could be used for plant safety applications such as showers and eye wash stations. Photo courtesy BS&B Safety Systems.|
For this reason, very high speed communications needs, such as those used for turbine anti-surge or high-speed motor controls and critical control applications, may not be appropriate for wireless communications and are not currently recommended, said Lara Kauchak, director of marketing for Emerson Process Management.
In the past, security has also posed a challenge. Because wireless signals are transmitted through the air, they can be intercepted. However, the "level of encryption and use of techniques like spread spectrum frequency hopping almost eliminate this fear," Dolenic said. Thanks to these improved security protocols built into the wireless networks and capabilities of wireless communication to prevent interception and hacking signals, many utilities using wireless no longer face security challenges.
In the general term of the word, "wireless" has also been dogged by connotations of unreliability. Wireless is inherently less reliable than hard line communications, said Michael Usrey, vice president of Sporian Microsystems. However, most wireless sensors for the utility industry contain logging capabilities that help minimize the impact of wireless network performance issues.
"Industrial wireless technology allows for a more dependable and consistent signal that is immune to radio-frequency noise," Dolenic said.
Today's wireless networks are as reliable as wired networks and in many cases just as fast, said Patrick Sweeney, director of marketing for Sierra Wireless' AirLink.
Aside from being lower cost and less intense to install than wired solutions, wireless is also more flexible, because it is not a permanent fixture in the plant. "It can be easily upgraded, maintained and managed, unlike fiber," Dolenic said.
One of Emerson Process Management's customers left them with a memorable quote: "Fiber is not forever." In the customer's situation, an existing fiber optic network had degraded over time during cold weather. "Replacing the network in a large distributed facility would have been very expensive," Kauchak said. "Their solution was to provide a wireless backhaul of the plant network using wireless transmission."
Pre-existing fiber optic networks at facilities are now fairly common. Therefore, a whole scale replacement with a wireless backhaul is typically not warranted without additional business drivers, like network extensions or requirements for wireless-enabled solutions. "There's no real reason to rip and replace," said Honeywell's Rogowski. Honeywell often installs wireless as a backup to — or an extension of — a fiber optic network. It also makes sense for a green field plant to go completely wireless, Rogowski said.
No Wires = Less Dollars
The major benefit wireless brings is the cost savings associated with the installation of the communications system, said Mike Koch, solutions architect for the utility practice of Motorola Solutions. Depending on the installation location, it may be impractical or even impossible to dig a trench to lay fiber optic cable. For example, laying fiber optic cable would be nearly impossible in or around steam straps or settling ponds. Emerson's Rosemount 708 wireless acoustic transmitter has been used to monitor steam traps within a power plant, resulting in a savings of up to $4 million per site.
Even if a cabled option is possible at a site, a fiber optic installation can cost $200 to $1,000 a foot, Koch said. On average, wireless can be 40 to 60 percent less expensive than wired for the total installed cost, said Emerson's Kauchak. Additionally, wireless can be up to 70 percent faster to install, helping accelerate project schedules, she said.
While the cost of wireless installation has stayed consistent in recent years, it is expected to rise in the next five to 10 years, Dolenic said. With consumer electronics, prices typically fall year after year as the technology advances – sometimes resulting in sacrifices related to quality and durability. However, "industrial wireless products do not trend in this fashion," Dolenic said. Industrial wireless prices have the potential to increase as providers seek out technological advancements and rigorous testing over the next few years.
Wireless in the Real World
Wireless can have a number of applications in a power plant. Here are a few examples of how power plants have adopted wireless networks:
- San Diego Gas & Electric wanted to implement a wireless architecture throughout the Palomar Energy Center combined cycle plant to access data that was previously unattainable through traditional wired solutions. Emerson installed five applications of its WirelessHART network, which have been used to provide access to additional plant and process data and helpful in improving operational efficiencies.
- Verizon Wireless deployed BlackBerrys integrated with SAP at a utility's power plant. This capability gave the workforce access to tools leading to increased production.
- A power plant in Europe recently used Honeywell wireless temperature transmitters to measure steam used for heavy oil burners. The transmitters were used to replace a wired solution that would have taken two months to install. The wireless solution, however, took two days to install.
- A Nebraska power plant installed Honeywell wireless technology to monitor its remote oil tanks. The plant is now able to efficiently monitor water runoff where electricity is not available.
- Central Iowa Power Cooperative (CIPCO) collects power measurements each month for both billing purposes and planning initiatives. The cooperative was previously using a process called probing that required field workers to physically collect meter data using an analog phone. The process was costly and time-consuming. CIPCO decided to install Sierra Wireless' AirLink Raven XT solution, enabling remote management, configuration and troubleshooting capabilities. The system has enabled CIPCO to monitor and control its network of wireless gateways from one central location, lowering the total cost of ownership.
Before a large-scale wireless installation begins, all power plant departments should develop an understanding of what the installation will entail. Wireless installers recommend that the wireless implementation be viewed as a partnership between the plant operator, company IT department and wireless supplier. Each party has a share in determining the outcome of the installation.
When a plant's decision to install wireless is supported company-wide, the facility can fully reap the benefits associated with the installation, including cost savings, increased monitoring capabilities and enhanced plant security. Some plants may only install wireless on settling ponds or storage tanks, while other facilities might undergo an entire wireless overhaul. Whether big or small, a wireless installation can have a powerful impact on the way a plant is managed and monitored.