Modeling overcurrent relay characteristics

摘要

An approach to computer modeling of the time-current characteristics of protective devices that relies on interactive manipulation and fitting of the curves, which are modeled mathematically as splines is presented. The approach is much easier to use than the commonly used curve-fitting methods, which are reviewed, and it does not require a digitizer. It has been applied successfully in a PC-based short-circuit and relay coordination program for overcurrent relays, fuses, and reclosers.