A flexible approach for overcurrent relay characteristics simulation

Accurate models of overcurrent (OC) with inverse time relay characteristics play an important role for the coordination of power system protection schemes. This paper proposes a new method for modelling OC relays curves. The model is based on fuzzy logic and artificial neural network. The feedforward multilayer perceptron neural network is used to calculate the operating times of OC relays for various time dial settings (TDS) or time multiplier settings (TMS). The new model is more accurate than traditional models. The model has been validated by comparing the results obtained from the new method with linear and nonlinear analytical models.