Smart Grid, Again? Really?

It’s understandable if that’s your reaction to what you anticipate will be yet another article extolling networked electric utility meters and talking refrigerators. These consumer-facing features continue to seem always another two or three years away from implementation. But what doesn’t get communicated nearly as often as all those Jetson-ian visualizations of our future connected universe are the little changes already happening. These advances are transforming the way utilities manage their operations—from transformers and generation assets, to connected residential photovoltaic (PV) systems, field-crew assignments and, well, just about everything else.

Improving our ability to move bulk electricity across system boundaries is becoming more important as remote renewable resources are called on to power urban centers and electric utilities search for ways to keep their customers’ lights on without building new generating plants. Moving electricity between operating regions is often impossible, though, because adjacent systems may be asynchronous, operating at different frequencies. The variable frequency transformer, featuring advanced (smart) sensing and communications technologies, now is helping to make such power transfers possible.

GE pioneered this technology and installed its first three transformers on the site of a 900-megawatt (MW) cogeneration plant in Linden, N.J. The turbines were installed in late 2009 to enable the transfer of up to 300 MW between the PJM Interconnection and the New York Independent System Operator. In December 2012, GE announced an additional 15 MW of capacity available for power transfers from one of the biggest electricity-­generating regions of the United States (its capacity totaled more than 185,000 MW, as of January 2012, according to Federal Energy Regulatory Commission figures) into New York City.

Making solar more useful

In a “dumb” grid, electricity runs one way—from a transmission system to a distribution system to a home or business. With PV panels popping up on residential and commercial rooftops (and even on utility poles in New Jersey), we’re beginning to send electricity in two directions, something local distribution systems weren’t designed to handle. As the number of systems grows, some worry that issues, such as clouds passing over PV-heavy neighborhoods (or utility-scale solar plants), could create voltage irregularities—on top of the transient events any distribution system already can suffer.

The gateway between a PV panel and the utility grid is the inverter, which turns PV-generated direct current into the alternating current acceptable to the grid. Researchers at the Electric Power Research Institute (EPRI) are working with manufacturers, such as Austin, Texas-based SolarBridge and Lawrence, Mass.-based Solectria Renewables, to define ways inverters could support the grid. For example, larger three-phase inverters used in large commercial and utility-scale installations could add reactive power, which could keep operations up and running during a transitory voltage sag that might otherwise have caused a brown-out or outage. Communications protocols now being developed will enable a utility to manage this functionality from a central control center.

Making buried lines visible

The outages following Superstorm Sandy this past fall showed just how vulnerable underground distribution lines can be. But these lines face a range of ongoing challenges in everyday operation, and line crews and area residents can’t see risks developing as they can with overhead wires. And, identifying where a problem might be located after the fact can be time-consuming and expensive.

Germantown, Md.-based Current has introduced a series of sensors that can pinpoint segment locations where underground faults are occurring. In addition, the system can help spot some issues before they occur by pinpointing degraded cables and monitoring current and voltage conditions. Electric utilities Xcel Energy and Pepco have begun incorporating the new devices in their grid-modernization efforts. 

Making critical data visible in the field

Effectively, using laptops in the field can require line crews to keep up with multiple applications and software packages, which can be a haphazard process, at best. EPRI has begun initial proof-of-­concept testing of an approach that brings together just about everything line personnel need to know on-site, using a simple, intuitive iPad-based interface; real-world testing is beginning this year.

The interface draws on the device’s geographic information system (GIS) capabilities and what’s called “augmented reality” (the ability to display location-based information, like, say, local restaurant reviews) over a location’s real-time image. For example, by pointing the device’s camera at a specific transformer, users could access line diagrams of existing circuits and equipment operating manuals, query the states of connected switches, and identify premises with outages. 

An important underlying enabling technology is the common information model, which is a new protocol for naming and messaging and was recently codified by the International Electrotechnical Commission. It is designed to enable communications across software packages and devices for cross-referencing. EPRI is working to bring this field-
visualization effort to market.

About the Author

Chuck Ross

Freelance Writer
Chuck Ross is a freelance writer and editor who has covered building and energy technologies for a range of industry publications and websites for more than 25 years. He specializes in building and energy technologies, along with electric-utility bus...

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