Read more great articles at http://www.engineering.com/
Tom Lombardo posted on December 28, 2014
A society that relies on technology becomes extremely vulnerable when the technology fails, and since most of our gadgets are electrical, protecting the power grid is a top priority. Failures can be caused by human error, weather, animals, or acts of malevolence, so grid designers must build in safeguards in order to keep faults from taking down major portions of the grid. The National Research Council published two documents that outline the potential problems with the US electrical grid and offer potential solutions based on current or near-future technology. Obviously the reports don't go into great detail, for security reasons. As Data (the android in Star Trek: The Next Generation) once said, "If you had an off switch, would you want everybody to know about it?" With that said, they did highlight areas that need to be addressed. Here's a brief overview. I've provided links to the original documents if you want to read more.
THE PROBLEMS
Because much of today's power generation causes pollution, the majority of electrical power is generated by large generators located away from population centers. Even wind farms, although pollution-free, need to be located in big open fields, away from tall obstructions found in cities. Long transmission lines carry electricity from the power plants to the consumers, although the route isn't direct. A break in one of these transmission lines - accidental or intentional - can cause widespread power outages like the 2003 event that blacked out portions of northeastern US and southern Canada.Real-time control must constantly balance supply and demand, and if that control breaks down major failures can occur. High-voltage transformers are large, expensive, and built overseas. If one or more of these transformers were attacked, it could take months to get it replaced. Although the grid can reroute power around some failed sections, there isn't enough extra capacity to handle the additional power from a major branch.Distributed generation is a double-edged sword. On one hand, it offers the possibility of independent microgrids that generate power for a small area. Hospitals, universities, and military bases are beginning to take this approach to protect themselves against grid failures. Although this helps the entities who use the microgrid, it also presents a challenge to the overall grid. Since microgrids are usually connected to the national grid, power flows both ways. Much of the power coming from a microgrid is generated by renewable sources whose output varies from moment to moment, making it difficult for grid operators to predict exactly how much energy is available at any given instant. Energy storage helps to alleviate the intermittent nature of renewable sources, but it presents the same issues as other distributed generation sources.
THE SOLUTIONS
The council offered several recommendations to enhance the grid's reliability, which include upgrading power plant and transmission line infrastructure, incorporating more grid-level storage (batteries, compressed air, pumped hydro, and supercapacitors), adding capacitor banks to handle variations in reactive power, installingadvanced circuit protection and communication equipment, and designing fault-tolerant computer hardware and software for use in grid control centers. In the event of a terrorist attack, it's likely that multiple systems would be affected. New strategies and protocols are needed to ensure that the automated systems that deal with single-mode failures don't adversely affect each other.
In any fault-tolerant system, there are critical points that simply must not fail. Substations represent these points in the grid's infrastructure, as do the aforementioned high-voltage transformers. The report suggests redesigning these components so they can be housed more securely indoors or underground.Smart grid technology can provide intelligent load-shedding, allowing limited resources to be directed towards critical customers like hospitals, police, firefighters, and military bases. But as the grid becomes "smarter" it's also more susceptible to cyber attacks. Appropriate levels of software security must evolve along with the control hardware and software to prevent hackers from interfering with grid operations.
OPPORTUNITIES
The report suggests that renewable energy sources, microgrids, and their associated integration technology take on a greater role in US energy production. Much of the same equipment that's needed to shift our energy production from fossil fuels to renewable sources is also a part of the strategy to make the grid more reliable and secure. As these tools evolve and grow side-by-side, care must be taken to ensure that the technology addresses all aspects of energy production, including quality, reliability, and security.The good old transformer - two coils of wire magnetically coupled - is the workhorse of the electric grid. Although simple and reliable, it's not particularly efficient and not at all programmable. Intelligent transformers made of high-power electronics could handle the stepping up and down of voltages, as current transformers do, and also deal with varying demand, routing of power, and reactive power compensation. Likewise, smart switches and circuit breakers can intelligently route power, isolate faults, and communicate with the grid operators and with other equipment.Here's one that might interest students who are looking for career opportunities. According to the National Research Council, "Going forward, the electric power industry will need increasingly more eclectic workers with skills to address digitization and the complexity of electronics, communications, computers, and highly integrated systems; the integration and operation of renewable energy sources. Much of this modernization will be driven by consumers' increasing demands for near-perfect reliability and quality of supply at a reasonable cost and by ever tighter environmental constraints."
Our century-old power grid runs surprisingly well; as a result, we've been lulled into complacency with the "if it ain't broke don't fix it" syndrome. Upgrading it will be a significant investment, but one that will pay dividends in advanced technology, high-tech jobs, economic growth, and national security. Are you up for the challenge?
