Modeling and simulation of inverse time overcurrent relay using Matlab/Simulink

Overcurrent relay is an important relay used to protect transmission and distribution feeders, transformer, bus coupler etc. It can be used as main or backup protection relays. The modeling of overcurrent relay and other protection relays is important in the research on the effects of network parameters and configurations on the operation of these relays. This research deal with modeling and simulation of inverse time overcurrent relay using commonly used Matlab/Simulink software. The developed model was tested with single line to ground fault and phase to phase fault with various fault locations and fault resistances to evaluate phase and earth detectors in sensing the fault current. Simulations results show the feasibility of the software to be used to develop the relay.