New-Tech Magazine Europe | Dec 2015 Digital edition

and various wireless technologies including ZigBee, 6LoWPAN, and sub- 1GHz connectivity. Consumers tend to associate smart grids with smart meters-home- monitoring devices that can provide the consumer with fine-grained data about usage trends-allowing them to modify consumption to, for example, take advantage of cheaper tariffs and allow utilities to smooth demand peaks. However, smart-grid metering comprises much more than the individual devices outside of homes, factories, and offices. Advanced- metering infrastructure (AMI) provides the two-way communications necessary for utilities to automate billing, remotely connect/disconnect individual meters, and implement demand-response programs. AMI networks also provide the ability for real-time monitoring of grid operations and immediate notification of outages to accelerate utilities’ response. What is more, renewable energy is a major challenge as generation extends beyond hydroelectricity and wind farms to “microgrids” comprising groups of households feeding power back into the network from solar panels. The inverter is a critical component responsible for the control of electricity flow between the PV cells making up the panel and the power grid. The challenge for engineers is how to do this in an efficient, reliable, and cost- effective manner[2]. In the U.S., ten states-including California, Florida, New York, Pennsylvania, and Texas-are leading the national effort to deploy the country’s smart grid. Together, these states have already been the recipients of $1.9 billion of the $4.5 billion earmarked in the American Recovery and Reinvestment Act for investment in the smart grid. This momentum is set to increase and is fueling demand for the electronics that are the foundation of many smart-grid systems. Silicon vendors have reacted by developing a range of components that enable electronic engineers to design products that underpin smart-grid applications; and

Figure 1: Smart grids will feature conventional and diversified electricity generation. (Courtesy of Infineon)

each of these products demands a power supply uniquely matched to the exacting demands of intelligent electricity distribution. Reacting to outages Apart from efficiency improvements, the key advantage of a smart grid is its ability to recover from faults caused by factors such as lightning, high winds, or falling tree branches. Utilities are understandably keen to prevent catastrophic failures such as the Northeast blackout of 2003. This was a widespread power outage that affected an estimated 10 million people in Ontario, Canada and 45 million people in eight U.S. states. Some people were without power for two days. Smart grids incorporate protection devices such as circuit breakers, which cut the supply when they detect anomalous events such as excess current or voltage. By establishing the location of the fault and taking advantage of the bi-directional energy flows enabled by a smart grid, utilities can isolate the small section of distribution line where the fault has occurred while using alternative lines to quickly restore power to the rest of

the grid. Many of these protection devices depend on power supplies from major semiconductor companies. Texas Instruments (TI), for example, offers a small form-factor, 12W power supply reference design to power the protection relays used in smart-grid circuit breakers (Figure 2). The design is notable because it is able to handle a wide range of both Figure 2: Wide-input-range power supply reference design for protection relays from Texas Instruments.

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