QUOTE(goamerica @ Aug 14 2003, 11:09 PM)
The only conclusion i can reach is that the lastest internet Worm, "Blaster" as it is called, converged on the systems at the Niagra-Mohawk plant & disrupted the systems, taking out the fail-safes and the grid itself was fried with help from the Worm
However in two previous major power outages in the New York area, there was no Internet for a worm to affect...
On the local television, they were showing the control room, and pointing out that the power variations were enough to "trip us off the grid" somewhere near Grand Rapids. The latest report was that 21 power plants failed within less than three minutes.
What they were describing was sensors, and relays. They would be absolutely impervious to an Internet virus. This is comparable to using a remote control to turn on your television. A sensor in the television picks up a signal from the remote and energizes, or deenergizes a relay. The actual relay in your television these days is most likely electronic; but at the power station, it will be more like a giant light switch. A relay, like a light switch either allows power to flow or interrupts it.
The power systems are designed so that a power overload will draw on other suppliers on the grid, but when it is being used to near maximum capacity, one small overload can really add up.
When I was an apprentice electrician, I miswired a control circuit in a classroom situation. The control circuit was protected by a 5 amp 120 volt fuse on a power limited control transformer. The transformer was tapped off 10 amp fuses on a 460 volt motor starter circuit. That was supplied by a 100 amp 460 volt breaker, supplied by a transformer which stepped down from a 2300 volt transformer, supplied by a 13,600 volt power generator. When the instructor examined my wiring and pushed the start button, there was a direct short to ground. The 5 amp fuse held, etc. We dumped the main generator off the grid, and took out power to 18 buildings.