Protective Devices Coordination via Computer Graphics

A method of coordinating short-circuit protective devices by the use of computer-generated graphics is described. Manufacturers´ time-current characteristic (TCC) curves for protective devices are stored and used by the program in choosing the ratings and settings of devices to produce a fully coordinated system. Computer drafting techniques output both a one-line diagram and time-current characteristic curves on conventional 4¿ by 5 cycle log-log format.