The variable performance of the operating rate in power electrical systems makes difficult to comply with quality standards with regard to conventional inverse-time overcurrent relays due to the fixed setting parameters thereof. The present invention provides a phase protection adaptive relay capable of modifying the setting parameters thereof according to the power system changes. The inventive relay has two adaptive criteria: an adaptive starting current useful for adjusting the starting current according to the load current, thus being a more sensitive relay compared to conventional relays, particularly in minimum charge rates; and an adaptive operating time, which guarantees a constant coordination interval between the adaptive relay and an overcurrent protective device useful for acting against any fault current regardless of the magnitude thereof, either in a stable or dynamic state. The present adaptive relay presents a higher sensitivity for detecting faults, and a reduced ope ration time under charge conditions below the threshold value of conventional relays. The adaptive relay does not require being coordinated, since this process is automatically performed within the relay. Moreover, the present relay is obtained by only carrying out a minimum change in the conventional relay firmware, without additional costs.
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