AC Power System Handbook, 3rd Edition

Disturbances on the ac power line are what headaches are made of. Outages, surges, sags, transients: they combine to create an environment that can damage or destroy sensitive load equipment. They can take your system down and leave you with a complicated and expensive repair job.

Ensuring that the equipment at your facility receives clean ac power has always been important. But now, with computers integrated into a wide variety of electronic products, the question of ac power quality is more critical than ever. The computer-based systems prevalent today can garble or lose data because of power-supply disturbances or interruptions. And if the operational problems are not enough, there is the usually difficult task of equipment troubleshooting and repair that follows a utility system fault.