Generator Response and Exposure During the June 25, 1998 Northern MAPP Disturbance

On June 25, 1998, there was a large power system disturbance in the MAPP region. The event was initiated by storm-related transmission line trips in the Minneapolis and St. Paul, Minnesota area at a time when the lines were heavily loaded. It resulted in electrical islanding of the northern portion of MAPP from the rest of the North American power grid. Recorded power flows and frequencies during the event provide insight into the response of the machines and operators. Analysis of the event has pointed out room for improvement in turbine governor controls, recording devices, information and control systems, and operator training.