Setting-free method for detection of asymmetrical faults during power swings

•The frequency components of p3ϕ(t) can be used as a fault indicator.•p3ϕ(t) oscillates at twice fundamental frequency when an asymmetrical fault occurs.•p3ϕ(t) oscillates at slip frequency (between 0.3 and 3Hz) during power swings.•A setting-free fault detector is developed based on the frequency components of p3ϕ.•The setting-free feature removes any daunting efforts of parameter tuning. This manuscript describes a setting-free fault detector based on the unique features of electric power. In contrast to the common practice in fault detection, which uses immediate signals, i.e., voltages and currents, the proposed technique has been inspired by raising this question “What if the information of voltages and currents are gathered in one quantity and fault detection is developed on this basis?” An intelligent choice can be the electric power, as it comprises the information of both voltages and currents. With that in mind, multiple unique features of electric power are disclosed to detect asymmetrical faults. The proposed fault detector works with fixed thresholds, i.e., revising is not needed from one system to another system. In other words, the fault detector is setting-free, which is remarkably an interesting feature in protective relaying. An IEEE-approved power system is considered to evaluate the dependability and security of the fault detector by extensive numerical simulations. The results are promising and show improvement to fault detection during power swings.