Spooks on the Power Line? Induction Generators and the Public Utility

Small-scale industrial waste heat recovery and cogeneration schemes are increasingly popular. Simplicity and low cost often favor induction generators, but many engineers lack experience with them. Public utilities wonder if their systems (and other customers) will see dangerous overvoltage, frequency drift, harmonics, or uncontrolled backfeed of power when induction generators are on-line. The commonly anticipated problems-the most frequent ``what ifs?''-will be explained and shown to be either seldom real or easily dealt with. More importantly, they differ little from situations involving induction motor circuits, about which utilities seldom show concern.