Overcurrent protective device coordination by computer

Overcurrent protective device coordination is defined, and the advantages of computerizing this process are explained. A computer program written by the authors, who are engineers responsible for performing coordination studies, is discussed. The program was written with emphasis on engineering flexibility. It can select settings for overcurrent protective devices to satisfy loading and protection requirements and to achieve the greatest possible degree of selective operation. Since complete selectivity is seldom possible, a means is provided whereby the engineer can indicate where compromises in coordination should be made. The data used by the program is discussed, as well as the setting process and the program output.