Interchange Capability and Contingency Evaluation by a Z-Matrix Method

A technique is described that permits the determination of the amount of power which can be imported from (or exported to) neighboring companies, without overloading "limiting" lines during an emergency situation, when certain "key" lines are out of service. The method is a multiple contingency extention of a technique described earlier.[1] The advantage of the method is the reduction in computer running time, as compared to the time required to obtain the equivalent information by complete power flow solutions, for the several conditions to be studied. The program has been extensively used with good success.[2]