摘要：AbstractThe technological advances of the electrical power system have brought several benefits including more robust and safe operation. Microprocessor-based digital relays may provide important features such as allowing quick and efficient setting according to the network changes. Considering the load variations throughout the day, such function becomes essential to maintain the coordination of the protection system. Adjusting the parameters of an overcurrent protective device manually may introduce non-optimal settings, mostly due to the difficulties in dealing with many possible solutions. This paper shows the modeling of an adaptive protection system based on Fuzzy Logic which parametrizes the pick-up current of inverse-time overcurrent relays by not demanding a centralized processing structure and communication among them. Two variables are taken into account: the pre-fault current and the variation of current. The IEEE 4-bus test system is used in ATP-EMTP program to illustrate the method considering several load, short-circuit and fault resistance values. The results confirms the benefits of smart protection system which adapts automatically according to the changes and has considerable sensitivity for high impedance faults. The proposed method is not dependent of system size.
