Wired vs. Wireless Technologies for Communication Networks in Utility Markets
Many utility industry operators are looking for new ways to maximize their investment in communication networks while ensuring reliable, secure data transmission. There is a variety of communications solutions, the two most common being wireless technology and wired options-such as copper and fiber-optic cable.
By Ashish Sharma
Many utility industry operators are looking for new ways to maximize their investment in communication networks while ensuring reliable, secure data transmission. There is a variety of communications solutions, the two most common being wireless technology and wired options-such as copper and fiber-optic cable. While both have a place in utility market applications, such as distribution automation, we are beginning to see an increase in the use of wireless technology.
There are many factors contributing to this increase-including cost savings, flexibility and power consumption. When looking at the big picture, a utility operator will discover each technology has its own advantages and disadvantages. Many feel the most reliable option for a communication network is the traditional wired approach. On the other hand, with so many different types of wireless technologies, the decision making does not stop once an operator chooses wireless. Communication networks are not one-size-fits-all, and it is critical that utility operators understand the type of technology needed to have the most effective communication network for their individual system. In addition, they need to consider the economic factors when searching for the best system their budget allows.
Applying Wireless Data Radios to the Utility Industry
Wireless technology can improve data transmission for applications in many industries. When looking at utilities, for example, wireless enables distribution automation improvement for the smart grid. One example is recloser control. Traditionally, this action is manually handled. By operating resclosers, electricity can be re-routed over the grid to bypass problem areas. By applying automation, both time and costs are saved, leading to optimized grid operation. This is one example of how automating distribution automation can improve overall smart grid performance.
Industrially hardened data radios, in particular, offer proven, reliable data transmission and advantages where:
• The system owner wants to control the communications,
• Cell phone coverage is inconsistent or non-existent,
• Communication security is a priority, and
• Budgets require efficient communications investment.
In other words, data radios offer utility operators a viable solution for meeting their distribution automation requirements while cutting costs. As the industry continues its growth, the need to identify ways to lower infrastructure costs, improve time-to-market and increase performance with reliable, easily installed networks are no longer a wish, but a requirement.
As the smart gird continues to make strides in the power industry, utility operators are looking for economical ways to manage their systems. To do this efficiently, a communication system is required.
Wired vs. Wireless Solutions
The wireless radio class that is industrially hardened and proven to be reliable in the harshest environments is commonly deployed in mission-critical industrial applications and life-or-death military applications. These radios may offer the most effective, economical solution when compared to other options. When compared with fiber, for example, wireless systems are easy to install. If a buried cable is damaged and requires repair or replacement, the costs can be high. Wireless systems are relatively maintenance-free, and, if maintenance becomes necessary, they are easily maintained. Once installed, top class wireless systems rarely need servicing. If maintenance is required, the best systems provide information regarding a pending maintenance concern, and the location or type of maintenance required can be remotely detected. Operators, therefore, only send someone out for service if and when necessary, saving time and money. If correctly engineered and installed, wireless systems will last maintenance-free for years. At least one of the top class wireless manufacturers provides backwards compatible solutions throughout its product lines-saving on maintenance as well as stocking and replacement costs.
In addition, wired options are priced by the foot. With wireless data radios, pricing includes ranges expressed in miles. A pair of top class serial radios, for instance, will likely communicate across 60-mile links with line-of-sight designs.
Wireless Communication Systems and Options- Pros and Cons
If an operator decides that wireless is the best option for his or her system, there are many factors to consider. The usability and ease of installation that come with wireless brings many different options to employ communications needs. The major ones include:
• Wireless Data Radios: The top industrially hardened class of proprietary protocol wireless radios systems are easy to install and require minimal labor; they don't require trenching or expensive equipment. In addition, users can quickly obtain real-time data, be operational and don't have to wait until a network typology is complete. Once a remote radio and master radio are installed, users can immediately monitor these points.
• ZigBee: A standards-based wireless solution, Zigbee offers a self-healing mesh network. These products, however, also have a direct sequence protocol that is susceptible to interference, especially when compared with proprietary protocol systems. The range is extremely short compared to others, and, as users add repeaters to lengthen the range, the throughput quickly degrades. At 230 kilobits per second (Kbps), the throughput without repeaters is acceptable in many applications. To achieve the self-healing networks, however, repeaters are required as repeaters are added-decreasing throughput and increasing cost.
• Cell Phone/Satellite: Cell phone and satellite technologies are public systems and, therefore, not controlled by the plant owner. Carrier-based systems such as these include monthly fees that add to the overall ownership cost, making it even more costly over time. Cell phone-based systems do not have a history for being backwards compatible. Replacing old technology with new technology can be costly. In addition, consumer applications take priority in such networks because that is the main application. What are the advantages? Sometimes these systems can reach extreme or remote locations where it isn't feasible to lay fiber or deploy a full wireless communication network. This is especially true with satellite systems. Satellite systems add significant delays in data transmission and, therefore, are not a good fit for many applications.
• Hybrid Communications: None of the systems previously described solve all problems in all situations. Hybrid networks-a blend of different technologies-often are important to consider. Hybrid networks also might include a mix of fiber, data radios, satellite or cell phone-based technologies. A hybrid system can be a more cost-effective solution for remote networks through lower hardware unit costs, fewer points requiring monthly fee-based satellite or cell connection modems, and lower power-consuming technologies.
Another Consideration for Wireless over Wired: The Copper Wire Theft Factor
A more recent factor in the surge of wireless technology is the increase in copper theft across the US. The struggling economy and increase in copper prices are key factors in this criminal activity. It has created such a major economic impact that in 2008 a Department of Energy report predicted copper theft costs nearly $1 billion per year. In March 2011, the cost of copper was nearly $5 per pound. Looking back 10 years, in March 2001, the going rate was under $1 per pound. This increase was sparked by a demand in developing nations such as China and India. In alignment with this increase, copper wire theft has become lucrative for thieves not only in the US, but around the world. They are paid cash by recyclers who often provide copper to commercial scrap dealers. Without physical proof that the copper has been stolen, these criminals easily remain under the radar. Despite the economic impact, there are no signs of it subsiding-making it critical for utility operators to take the initiative and protect their infrastructure.
Copper thieves often target power lines, heating and cooling pipes, and grounding wires-all necessary components of the modern world. According to open-source reporting, in March 2008, approximately 4,000 residents in Polk County, Fla., lost power after copper wire was stripped from an active transformer at a Tampa Electric Co. (TECO) facility. The blackout cost nearly $500,000. Because of examples such as this, operators are looking for ways to prevent thefts, and many are finding that using wireless technologies make them less of a target.
Thieves often have easy access to copper because many times utility sites are remotely located. Without a security system in place, thieves can easily access the metal in daylight, stripping the infrastructure of its critical elements. Today, replacing or choosing wireless communication technology as opposed to copper wire solutions is one way to fight copper theft. In the smart grid industry, most thieves are crafty enough to avoid stealing the copper wires from high-voltage electric distribution or transport lines; instead, they are going for the communication networks that are copper-based. With the smart grid, the consequences of disrupting critical data transmission can have expensive consequences, such as the power facility in Florida. Without proper data transmission, everything from power generation to distribution can be disabled. By using wireless for communication, operators can prevent copper theft. While copper communication lines historically were considered more secure, we are starting to see a shift in this thinking, especially in utility industries, as a direct result of copper wire theft. Operators, however, must understand wireless comes with its own set of security concerns. It is critical to look for a system that can handle potential threats.
Security for Wired vs. Wireless
Unlike traditional wire-lined data communication, wireless is based on electromagnetic waves using radio frequencies (RF) propagating through open space. This provides wireless with some unique advantages, as communication endpoints don't need to be tied down to a fixed location and dependent on a physical cable. The flexibility of wireless data communication, however, comes at a price. Electromagnetic waves are non-discriminatory when it comes to access. While a wired connection requires physical access to the cable, wireless connections can be made anywhere along the path where the electromagnetic waves propagate. Consequently, security-as in secure access-becomes more important for wireless data communication.
In 1941, Hedy Lamarr, an Austrian-born actress, and George Antheil co-patented a secret communication system that allowed radio control of torpedoes that could not easily be discovered, deciphered or jammed. The system used frequency hopping, or coordinated, rapid changes in radio frequencies that literally "hop" in the radio spectrum and evade detection and the potential of interference-in other words, being suppressed or jammed.
Her idea was ahead of its time and not implemented in the US until 1962, when it was used by US military ships during a blockade of Cuba, and is now the basis for modern Frequency Hopping Spread Spectrum (FHSS) wireless communication systems.
FHSS wireless systems are resilient to impairments such as interference and jamming. Other effects can be observed when wireless signals travel through space, such as the multipath phenomenon, because they use only small amounts of radio spectrum at a time and don't dwell long at that frequency-instead, they quickly hop to another frequency. This makes a Denial of Service (DoS) attack on FHSS systems difficult-but not impossible. Today, some top class wireless data radios use FHSS to ensure secure utility application data transmission, including distribution automation.
High costs, difficult installations, copper theft and more are driving operators to consider alternatives to wired solutions. In many industries, including the military, there is evidence that wireless data radios are a viable alternative. These technologies provide long-range, reliable and affordable solutions. A wireless system can potentially save a company millions of dollars in installation fees.
Operators, however, need to be aware that not all radios are created equal. Top class radios provide industrially hardened equipment and the flexibility to perform in nearly any situation. By using FHSS, they can also offer enhanced security, easing the minds of those who trust wired for its reputation as the most secure method for data transmission. The increase in copper theft also supports the case for wireless over wired and offers a reason for operators to think twice about choosing copper wiring. Any manufacturer who has a solid product offering is probably willing to provide operators with test equipment to prove the technology before they buy it. It is easy to use, quick to install, reliable and low risk. When return on investment is a key in determining the best communications solution, the benefits of top class wireless data radios should be part of every decision process.