Providing premium power through distributed resources

The modern industrial facility depends on sensitive electronic equipment that can be shut down suddenly by severe power system disturbances. A large number of these disturbances on the power system are a result of line faults which can cause momentary voltage sags. This results in equipment malfunctioning and high restart cost. This papers describes the control of distributed resources as a solution to such problems. In particular the focus is on systems of distributed resources that can switch from grid connection to island operation without causing problems for critical loads.