Contingencies Evaluated by a Z-Matrix Method

A method has been developed suitable for on-line evaluation of contingencies that requires a relatively small computer. The effect on critical lines, produced by removing a line from service or by changing the generation schedule, can be determined as an on-line function of a computer that is installed in the system operator´s office. The method can also be used by system planning personnel to reduce the number of detailed power flow cases that must be made in an expansion study.