Secure wireless technology targets utility distribution automation applications

Secure wireless technology targets utility distribution automation applications

When evaluating communications systems for the smart grid, utility decision makers must be prepared to face a lot of options, especially when it comes to wireless

BY CURT GOLDMAN,

Utility Market Manager
FreeWave Technologies
www.freewave.com

Today, wireless technology has become accepted as an optimal communication solution for applications in many industrial settings. In the oil and gas industry, for example, wireless technologies have become a leading, if not the go-to choice, for monitoring and control. The electric power and smart grid markets also continue to see an increase in the use of wireless technology, especially for distribution automation applications.

As utility operators and decision makers continue to look for new ways to make a smarter power grid, it has become clear that a secure communication network is critical in ensuring efficient and effective delivery of power. Each layer of the grid (generation, transmission, distribution and consumption) has varying requirements for monitoring and control. Wireless solutions are the “glue” that brings the smart grid together.

Fig. 1: As utility operators and decision makers continue to look for new ways to make a smarter power grid, it has become clear that a secure communication network is critical in ensuring efficient and effective delivery of power.

However, there is a challenge because while the use of wireless technology has begun to increase, the electric power industry traditionally has relied upon wired technologies for communication. Some utility operators still question the security capabilities of wireless because they simply are not familiar with all of the options available for the smart grid market.

Today there are wireless communication solutions that offer security features trusted for critical government and defense operations. For more than a decade, these technologies have proven to offer the same level (if not more) of secure data transmission as a wired solution. As more utility decision makers learn about this type of wireless technology and see it in action, they are adopting it as a viable solution.

In fact, wireless providers are consistently developing new control and monitoring technologies for distribution automation applications, such as fault circuit indicators and capacitor bank control. However, before learning about the latest wireless applications, it is critical for decision makers to understand the security advantages that certain wireless solutions offer.

Wireless for distribution automation

At the distribution automation layer, many critical functions and actions are automated, such as the monitoring of critical feeders, fault detection, isolation and restoration to reduce the duration and impact of outages, supporting the shifting of loads between sources to help avoid or alleviate overload conditions, controlling capacitor banks and more. The extension of intelligent control over electrical power grid functions to the distribution level and beyond (via distribution automation) is a key enabler for the smart grid.

For example, many electric utilities have implemented wireless communications solutions in supervisory control and data acquisition (SCADA) systems for better control over transmission-level equipment. However, as reliability and load requirements continue to increase, so does the need for a reliable data communications network to serve automation purposes within the grid.

Differentiating wireless technologies

When utility decision makers and/or operators begin their search for building out a communications network, it is clear they will find a variety of wireless options. As more decision makers choose wireless, emerging solutions continue to be developed as well.

In many cases, operators might find that different technologies are suited for different layers of the smart grid, leaving them confused and unsure of how to make the right choice for their particular need. Perhaps the most important caveat in selecting such a system is that utility decision makers must understand the communication requirements for their smart grid before they choose a solution.

No single technology can satisfy the requirements and all of the priorities of all utility operators, especially in a system as complex as the smart grid. For example, there are standardized wireless technologies that often are used for smart grid applications.

These industry-standards-based devices offer many positive attributes, however, a negative aspect is that the only requirement to connect this wireless system is an “off-the-shelf,” standards-based device (that is, Wi-Fi). When it comes to security, this could be perceived as a disadvantage because of widespread knowledge about what makes this wireless technology work and the protocols that are used.

For example, if someone wanted to use the Wi-Fi offered to a local coffee shop’s customers, all it may take is a Wi-Fi card, password, and a parking spot close enough to access the shop’s Wi-Fi signal. However, for an application that is sending small amounts of data across a short distance, a standards based device like ZigBee may be a good choice, but the utility must take security requirements into consideration as well.

It has been proven that proprietary systems and devices actually offer a higher degree of security. Intruders will find it much more difficult, if not impossible, to access the signal of proprietary wireless technology, such as frequency-hopping spread-spectrum (FHSS) data radios. In the distribution layer, where secure data transmission is essential in preventing blackouts and other detrimental events, FHSS may be an ideal communication option. FHSS radios include unlicensed systems, such as 900-MHz spread-spectrum radios.

What makes FHSS technology secure?

FHSS was developed in 1941 when Hedy Lamarr, an Austria-born actress, and George Antheil co-patented a secret communication system that allowed radio control of torpedoes that could not be easily discovered, deciphered or jammed by the enemy. ( http://patft.uspto.gov/netacgi/nph-Parser?Sect2=PTO1&Sect2=HITOFF&p=1&u=%2Fnetahtml%2FPTO%2Fsearch-bool.html&r=1&f=G&l=50&d=PALL&RefSrch=yes&Query=PN%2F2292387). The key to developing the system was frequency hopping — coordinated, rapid changes in radio frequencies that literally “hop” in the radio spectrum, thus evading detection and the potential of interference (being suppressed or jammed).

Lamarr’s idea was not implemented in the U.S. until 1962, when it was used by U.S. military ships during a blockade of Cuba (after the patent had expired). Today, it is the basis for modern FHSS wireless communication systems. FHSS wireless systems are very resilient when it comes to impairments such as interference (deliberate or coincidental) and “jamming.”

Other effects can be observed when wireless signals travel through space, such as the “multipath” phenomenon, simply because they use only very small amounts of radio spectrum at a time and don’t dwell (or remain) at that frequency long, instead “hop” quickly to another frequency.

Identifying security concerns with wireless

There are many security concerns when it comes to the smart grid. Electricity is one of the most essential pieces of our critical infrastructure. Without it people could not communicate, conduct business or complete many daily tasks.

A communications network that is constantly monitoring the smart grid can notify utility operators and pinpoint failure points along the grid. This is why it is absolutely essential for a reliable communication system. If the communications system is breached, then it leaves operators unable to receive a real-time update on the health of the grid. When it comes to wireless technologies, the two most common threats to data communication networks today are denial of service (DoS) and intrusion.

DoS is an attempt to make a computer resource or network unavailable to its intended users. DoS could be as simple as jamming an electric or electromagnetic signal or as sophisticated as saturating a system or network with communication and data traffic intended to overwhelm and avoid legitimate data to get through and be processed.

The consequences of DoS in the smart grid could lead to a transformer explosion, for example, if the technology is unable to monitor levels of cooling oil because it has been jammed or interrupted. Penetrating and intruding into a network or computer resource requires a different level of sophistication. The consequences can range from spying or stealing information to corrupting data or maliciously and intentionally causing harm or destruction by taking over network and/or computers and control systems.

When using a reputable provider of FHSS technologies, these types of security problems can be nearly eliminated. Wireless FHSS communication networks that have been used and proven by the military to be a reliable solution for many years are easy to install, if done properly, and can offer the same reliability and security that wired systems offer at a much lower cost. Because of the strengths of FHSS wireless data radios, utility decision makers who are familiar with this type of solution are increasingly implementing a wireless communication system into their smart grid, especially in the distribution layer.

Applications in distribution automation

Within distribution layer, there are a variety of devices connected to the main distribution system, such as substations, “inside the fence” systems, capacitor banks, reclosers and sensors. Automating distribution fulfills the utility’s objective to provide communications to all of these devices so that up time is maximized and that maximization is achieved affordably.

It is critical to have a highly reliable system with enhanced security features, accurate data and speed of data transmission. It has been proven that the right system tools will help the utility satisfy customers, shareholders, members, or taxpayers.

Fig. 2: Within distribution layer, there are a variety of devices connected to the main distribution system, such as substations, “inside the fence” systems, capacitor banks, reclosers and sensors. Automating distribution fulfills the utility’s objective to provide communications to all of these devices so that up time is maximized.

Communication options often include unlicensed systems or licensed systems. It is important to explore how fast data is needed and the amount of data that must be transferred. The 902–928-MHz band (IP unlicensed radios) is suited for transmitting a lot more data than a strictly licensed band.

In the 902–928-MHz band there might be 112 channels of communications that will be operating from 115 kbit/s to 1 Mbit/s. On the licensed band, however, systems are narrower. The Federal Communications Commission (FCC) allows a 12.5-kHz channel, 5-kHz channel, or 50-kHz channel and that translates to not as much data being passed. Common applications within distribution automation include AMI back haul, distribution management (DMS), substation automation (SSA), demand response (DR), supervisory control and data acquisition (SCADA), load management, Volt/VAR optimization and energy management (EMS). While these are some of the more well-known applications, wireless providers continue to develop new distribution automation technologies based on customer’s needs.

Capacitor bank control

Operators use capacitor banks to help correct things like power factor lag or phase shifts in alternating current (ac) electrical power supplies. They also can be used to increase stored energy and improve the power quality of the system.

When a reliable wireless network is used to control and monitor the capacitor banks, it ensures greater energy efficiency and a smoothly operating distribution system in the grid. Real-time data allows operators to receive critical data faster, and from remote locations.

Fault circuit indicator monitoring

Fault circuit indicators (FCI) situated along power lines are deployed to detect fault current. As many operators are aware, if the current defaults on a line with an FCI, it will know the distance that the current has failed from pole to pole.

Operators can then pinpoint the location of the fault along the power line. Many operators, however, are unaware that there are technologies available that can be embedded within the FCI, extract fault data and send it back to a central information center on a real-time basis.

Previously, this application required a relay of data to several different points before it was returned to a central point. Wireless technologies now available for this application are embedded within the FCI and can transmit data up to 60 miles, ensuring fast identification of a fault. This prompts a fast reaction from the utilities to help prevent a major blackout from occurring. This contributes to the goal of distribution automation mentioned above, by narrowing down problems when they occur along the line, which helps maximize up time, prevents power delivery issues and saves the utility money.

At the end of the day, effective data transmission keeps utility operators informed on the health of their smart grid, allows it to run smoothly and ensures proper delivery of power. By deploying a communication network for key applications in the grid, especially within distribution automation, the operators can have critical data delivered to their fingertips on a real-time basis.

This allows them to constantly monitor the system, and react in a timely manner in the event of a malfunction, whether it is a transformer running low on cooling oil, a fault on the power line, or the need to increase stored energy in capacitor banks when needed, among many other applications. This data all can be delivered with secure wireless technologies that are trusted for mission critical applications in multiple industries.

When evaluating communications systems for the smart grid, utility decision makers must be prepared to face a lot of options, especially when it comes to wireless. If security, reliability and real-time data are key criteria for a utility’s communications system, especially within distribution automation, then FHSS wireless data radios might be the best choice.

However, be prepared to research vendors as well — a reputable wireless provider will provide path study network design, offer excellent customer support and allow potential customers to conduct a pilot before purchasing a system. As wireless continues to become the standard for communications in the electric power market, utilities can continue to expect new options and applications for secure wireless technology. By having an awareness of the options on the market, a utility will be much more likely to find the system that meets their requirements. ■