Another tidbit from my ERCOT friend in Texas. I don't know where he got it from.
Blackout called almost inevitable, communications system inadequate, early analysis finds- When an electrical transmission line sagged into a tree just outside Cleveland at 3:32 p.m. on Aug. 14, the events that would lead to the greatest power failure in North American history began their furious avalanche, according to an extensive analysis of the blackout. The failure of that transmission line was crucial, because it put enormous strain on other lines in Ohio. Soon, the utility that serves southern Ohio, with its overloaded lines close to burning up, sealed itself off, creating, in very real terms, an electrical barrier between southern and northern Ohio. What happened next, by this account, was almost inevitable: To the north, Cleveland, starving for electricity, began to drain huge, unsustainable amounts of power from Michigan and then across the Canadian border in Ontario, knocking out more lines and power plants and pushing the crisis to the borders of northwestern New York. First the New York system, acting to protect itself, sealed the state's border with Canada, the analysis found. But that only created a devastating problem: New York power plants, without anywhere to quickly send electricity not needed within the state, overloaded their own system. That in turn quickly led to a general shutdown. That picture, based on data from the utilities involved, was presented by Cambridge Energy Research Associates, a private energy consulting firm. Both Pat Wood 3rd, chairman of the Federal Energy Regulatory Commission, and Cambridge Energy are unequivocal on one emerging aspect of what went wrong: the system for communication among the people and organizations that operate that part of the electrical grid was inadequate. When problems soar around the grid in seconds, as they did that day, Wood said, you need to make sure that the communication between the different regions can move similarly fast. That cannot happen in the current setup, in which the various oversight organizations are fragmented and often connected only by phone lines, Wood said. Michael Holstein, vice president and chief financial officer at the Midwest Independent Transmission System Operator, which helps manage electrical flows on the grid for some companies in the region, called the Cambridge Energy analysis an interesting hypothesis. But he rejected any suggestion that a lack of communication could have contributed to the problems. At a certain point in time things happened so fast that human intervention was not possible, Holstein said. That assessment was echoed by the organization that carries out day-to-day management of the grid in New York, the New York Independent System Operator. Ken Klapp, a spokesman for that organization, said events moved too quickly for humans to react and keep the state from going dark. Several officials from industry groups charged with preventing blackouts said that the Cambridge analysis seemed consistent with information they had collected so far. The analysis also meshed with data released by American Electric Power, the southern Ohio utility that sealed itself off from the developing trouble to protect its lines and customers. In its case, as happened elsewhere around the system, sturdy circuit-protecting sensors and relays detected enormous flows in wires headed toward its region of Ohio. Henry Fayne, American Electric's executive vice president for energy delivery, said, It is likely that the automated controls tripped some transmission lines moments before they would have burned down because of extremely high power flows out of our system. American Energy officials insisted that they had been in extensive contact with officials with FirstEnergy, the utility whose lines were failing to the north, during roughly an hour of escalating trouble. According to Cambridge Energy, the slide to darkness started when the loss of a single transmission line near Cleveland at 3:06 p.m., in itself an unremarkable event, was followed at 3:32 by the shutdown of a second line after it overheated and sagged into the tree. Normally, procedures would have delayed sales of power or diverted them through other lines. But those actions can require half an hour or more, according to various utility officials, and there was only about half an hour to go before the troubles hurtled through the system. American Electric Power's safety systems isolated the trouble spot, as designed. But the severing of the two crucial Ohio lines was the equivalent of suddenly damming an onrushing stream: the flow had to divert to find a way to reach the Cleveland area. The power did that by spilling around the barrier into Indiana, then into Michigan and finally back to Ohio. Within a few seconds, the modest amounts of power, around 200 megawatts, that was flowing from a utility in lower Michigan, the International Transmission Company, soared to 10 times that amount. At about the same time, the power that had been flowing from International Transmission to Ontario suddenly reversed, pouring still more electricity onto that part of the grid, while another Michigan utility began supplying power to the very same area in an effort to meet the demand. The chain of events overwhelmed lines and power plants on the International Transmission system, and they all began shutting down. By a little after 4:10, most of the system was out of service. Aug 25, 2003.
