PJM Interconnection: model of a smooth operator [electric utility experience]

During the summer of 1999, searing heat waves across the United States set air conditioners roaring and brownouts rolling through the grid-that network of substations, transformers, cables and towers that conducts the flow of electricity from supply center to demand point. Here, the author describes how, while local utilities faced outages at the distribution level in the mid-Atlantic states, grid operator PJM Interconnection LLC, of Norristown, Pa., kept its transmission network humming, though not without some difficulty and what the company calls "learning experiences".