Info Technology World Wide

Part Two, Number 8

Technological applications in the tech area of "Power Grid Control".

8. Power Grid Control: Power grids carry the seeds of their own destruction: massive flows of electricity that can race out of control in just seconds, threatening to melt the very lines that carry them. Built in the days before quick-reacting microprocessors and fiber optics, these networks were never designed to detect and squelch systemwide disturbances. Instead, each transmission line and power plant must fend for itself, shutting down when power flows spike or sag. The shortcomings of this system are all too familiar to the 50 million North Americans from Michigan to Ontario whose lights went out last August: as individual components sense trouble and shut down, the remaining power flows become even more disturbed, and neighboring lines and plants fall like multimillion-dollar dominoes. Often-needless shutdowns result, costing billions, and the problem is only expected to get worse as expanding economies push more power onto grids.

Engineers are developing hardware and software to track electric flows across continent-wide grids several times a second, identify disturbances, and take immediate action. While such "wide area" control systems remain largely theoretical, one has been designed and if it works as advertised, it will make power outages 100 times less likely, protecting grids against everything from consumption-inducing heat waves to terrorism. It is possible to push more power through the grid while, at the same time, making the system more predictable and more reliable, according to some engineers.

Real-time control systems are a natural outgrowth of a detection system pioneered in the 1990s by the U.S.-government-operated Bonneville Power Administration, which controls grids in the Pacific Northwest. In this system, measurements from sensors hundreds to thousands of kilometers apart are coded with Global Positioning System time stamps, enabling a central computer to synchronize data and provide an accurate snapshot of the entire grid 30 times per second; fast enough to glimpse the tiny power spikes, sags, and oscillations that mark the first signs of instability. An earlier version of Bonneville's system helped explain the dynamics of the 1996 blackout that crippled 11 western U.S. states, Alberta, British Columbia, and Baja California; western utilities subsequently reconfigured their operations and have thus far avoided a repeat.

Many utilities are already implementing elements of real-time grid control‹for example, installing digital network controllers that can literally push power from one line to another or suppress local spikes and sags. Tied into a wide-area control scheme, these network controllers could perform more intelligently. The evolution toward real-time, wide-area sensing and control has begun.