In a power distribution system, overcurrent protective devices are used to isolate only the faulty section so that the remaining system can continue to operate normally. Since faults can occur anywhere in the system, many protective devices are required, such as fuses, relays and reclosers. In a good practice, the isolated area must be as small as possible and only the devices nearest to the fault should operate. To perform this task, time discrimination between successive devices must be correctly chosen to provide the necessary means for the coordination of protection. Therefore, the algoritm of overcurrent coordination for different protective devices needs to be formulated to provide a consistent approach to decide the selection,characteristics and settings of devices used. Thes algorithms of coordination can be incorporated into computer simulation to improve the present manual method of carrying out coordination study. In this respect, the computer aided coordination study will provide an attractive alternative for the coordination of variousprotective devices. This simulation of overcurrent coordination, as well asthe approach to the modelling of TCC curves are needed to be designed for a successful implementation of a semi-automated coordination study. It is the purpose of this project to look into the various elements needed for a succeful implementation of overcurrent coordination by computer.