Low voltage caused by contingencies predicted by a high speed Z-matrix method

Previous work using the Z-matrix in the analysis of contingencies has been limited to the determination of over-loaded lines. In developing countries, where the transmission systems are weak, low voltage may occur as a result of a contingency. This paper is a report on a high speed method of determining voltage changes caused by the loss of transmission elements. This is an extention of the previous work on the analysis of contingencies using the Z-matrix. Test results of a single case of a double contingency on a major system are given.