Federal Triangle: Micro-Grids and Power Islands
When you think of the fact that only $20 of $79 billion in annual cost is industry's share of national economic loss due to electric power interruptions (residential is $2 B and commercial is $57 B), does that make you think, "It's not my problem" or "sorry about that, dude?" This is a huge problem and getting bigger; a complex subject discussed at the Reliability Summit sponsored by Information Forecast Inc of Canoga Park, Calif., and held in Washington, D.C. the last days of September.
Electric power grid reliability for consumers means "no blackouts" but in the power sector it means "no cascading outages or uncontrolled separation of interconnected systems" and therein is a subtle difference. Blackouts are mostly distribution failures and local in nature, while the cascading outages can originate anywhere after the generating station but usually begin in the transmission network-the electricity pipelines. So grid reliability requires real-time, dynamic monitoring systems to measure conditions that describe reliability. The old way of measuring reliability and risk associated with failure was to account for peak load scenarios; that is, use static probabilities to assess failures and not account for system dynamics. New technology allows real-time feature measurements, which give moment-to-moment update of reliability and risk. These analyses no longer measure independent events, and even account for human error (such as failure to act or to execute incorrect actions in grid management) and assess protective and control system dynamics as significant contributors to system health and performance. What is emerging today is a more reasonable approach for industry users to shift suddenly into "power island mode" by disconnecting from the grid and becoming autonomous during times of high risk and declining reliability. This would have been a much better alternative for U.S. Steel Gary Works during the power outage of 14 August 2003 when they were caught with a furnace that froze into a load of metal that became a $250 million loss. Further, it was a loss not covered by insurance, because available technology could have prevented the problem.
Most industrial operations contain all the pieces to make needed measurements, the distributed and programmable logic controllers, SCADA and all the databases and transaction monitors that can report worldwide events in seconds. As usually happens, it is a combination of events that foretell problems as they emerge, when correct response is needed, before effects are irreversible. This is now possible, due to what folks in the grid reliability sector call a "real-time performance management platform." When a grid monitor detects anomalies in grid stability, users can reconfigure their place in the grid topology and prevent participation in a collapse. In practice, this is done by measuring power line voltage, current and frequency, and identifying increases in reactive power while real power decreases. When a transition from positive to negative power factor occurs early in this scenario and loss of coherency or other frequency abnormalities are witnessed, a problem is coming. With ability to calculate phase angle in real time, it is feasible to know when to become an island and disconnect from the grid. What Michehl Gent, President of North American Electric Reliability Council, said, "it all happened in about nine seconds" is not fact; there was a warning of more than 2.5 hours for those with abilities installed to read the signs.
All this has little force and effect in our government controlled world, so it is up to prudent business executives to do for themselves what bureaucracies do not. Since government (FERC) directed (Orders 888 and 889) separation of power generation and transmission and resulting Regional Transmissions Organizations (RTO) have inadequate investment with a declining quality infrastructure, reliability problems are forecast to get worse. Therefore, it is suggested that larger users and those in a vulnerable community of interest explore forming micro-grids; this is not a form of "distributed generation" but creates a "power island" during times of grid instability. Typically, for a single facility to consider micro-grids, use is 0.5 MW and multiple facility load is 1 to 4 MW. Payback is from 6 to 20 years, efficiency is dramatically better than conventional, reliability can be over "five-nines," and prices are higher but reasonable.
At the conference and in research for this article, several information sources appeared and are www.osisoft.com, www.navigantconsulting.com, and www.kema.com.
I have only verneer knowledge on the subject and make no recommendations other than micro-grids seem like something worth checking.