Microcomputer Generated Protective Device Coordination an Interactive Approach

In recent years, expensive mainframe and mini computers have been applied to coordinate protective devices. A method of protective coordination is presented which can be run on an inexpensive microcomputer graphics system. This method is based on a "Computer Assisted Drafting" approach where the computer acts as a drawing aid to the power systems engineer. Various protective device time-current curves are selected from the computer database and drawn on the computers display screen. The settings of these displayed curves can then be optimized by the system engineer. Final results are drawn by a high quality pen plotter on standard time-current characteristic logarithmic paper.