Applications for electric power and the Smart Grid
For electric power operators, achieving efficient and reliable power delivery is crucial. Technological developments continue to guide the industry toward a smarter grid. One development is the implementation of communication networks in the electric grid. With the right communication network in place, a Smart Grid can reduce peak demand, shift usage to off-peak hours, lower total energy consumption and improve reliability.
However, the right communication system is different for each layer of the Smart Grid. At the distribution automation layer, for example, many actions are managed, such as demand for and control over the amount of electricity created/required versus the amount used/delivered to the use point. To effectively automate the distribution grid, a reliable communication network is required that balances speed, distance, security and ease of use.
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Smart Grid layers
Defining a Communication Network
A wireless communication network consists of broadcast points (transmitters) with receivers and transceivers where both fixed and mobile units can communicate with each other over broad geographic locations using radio waves. In the industrial world, including the Smart Grid, a communication network mostly will be comprised of fixed applications with a radio connected to a remote terminal unit (RTU), programmable logic controller (PLC) or some other intelligent device. Often, there is an input/output (I/O) device in the wireless network that communicates with a central location where the Supervisory Control and Data Acquisition (SCADA) network and telemetry is monitored and controlled.
Wireless Technologies for a Communication Network
No single wireless technology can satisfy the requirements and priorities of all applications, especially for a system as complex as the Smart Grid. The first step in determining which technology is the best choice for each layer of the Smart Grid is to evaluate what is most important to the operator in a communications system and what their individual needs are in advance. For some applications, reliability is critical. In the distribution layer, it is critical to have a highly reliable system with enhanced security features, accurate data and speed of data transmission.
Industrially-hardened wireless radios, including unlicensed frequency hopping spread spectrum (FHSS) and licensed frequency radios, are reliable in the harshest environments and are deployed daily in mission-critical industrial and military applications. At the distribution automation layer, they may offer the most reliable, economical solution.
For example, compared to fiber, wireless systems are easy to install. If a buried optical cable is damaged and requires repair or replacement, the costs can be high.
Some wireless systems provide information regarding pending maintenance concerns, and the location or type of maintenance required can be easily detected remotely. With this pinpoint information, operators send a technician out for service to the precisely right location if/when needed, saving time and resources.
If designed and installed correctly, wireless systems will last maintenance-free for years. Additionally, when compared to satellite and cellular options, certain wireless radio providers do not incur monthly fees that make satellite and cellular solutions more expensive over time. In fact, most comparisons show recurring data fees from cellular communications over a two-year period are equal to the cost of all devices for the same network with unlicensed FHSS radios.
FHSS radios also offer advanced security features that protect the Smart Grid from attack. For example, a major security concern is denial of service (DoS). In a DoS attack, an intruder accesses the network and blocks communication by crippling the network with excessive data. At this point, the utility no longer controls what is happening on the grid. This is dangerous and could cause a variety of risks, from a homeland security issue, to safety of the operators and teams of people working in the field.
It is critical to know whether the power is off in a certain area, if it is working in other areas and the high-level system view to keep workers and residents safe. At the distribution automation layer, FHSS wireless systems have proven to be very resilient to DoS by design. These wireless data radios use tiny amounts of radio spectrum at a time and will “hop” to another frequency quickly. Comparing this to standards-based radios (example: 802.11, Wi-Fi) which are available at electronics and retail stores, this makes a DoS attacks on FHSS systems difficult, if not completely impossible.
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Smart Grid application
Monitoring with Wireless I/O
Also available for electric power operators are wireless I/O radios that use FHSS technology. Wireless I/O offers substantial and measurable cost savings in terms of engineering, installation and logistics as well as dramatic improvements in the frequency and reliability of field data collection.
In applications with a central processing device, wireless I/O enables users to extract full diagnostic data and predictive intelligence from the devices that then automatically notify the appropriate personnel of the precise problem before a costly asset, unit or plant shutdown occurs. I/O acts as the eyes, ears and hands of the wireless communication network whose overall goal is to deliver more value from the same assets.
As a result, wireless I/O is becoming increasingly popular to help reduce expenditures.
The majority of wireless I/O systems being deployed today are used for data acquisition, but increasingly more users are using wireless I/O in control applications. The electric power and Smart Gird markets, in particular, have many processes that can benefit from wireless I/O.
Wireless I/O for Power Transformer Monitoring
One example of a wireless I/O application in the Smart Grid is power transformer monitoring. Located in distribution substations and throughout the distribution grid, transformers critical. Transformers take extremely high voltages from power generation or transmission and decrease the energy level for proper distribution and delivery. This process is crucial for safe and efficient energy distribution to power homes and businesses. With extremely high power levels flowing through the transformers, it is often necessary to use a cooling system to prevent damage, most commonly using oil cooling. A damaged transformer is extremely costly to the utility and can cause power outages in the communities receiving power
With wireless
