Improved WABP based on direction comparison principle and fault current component distribution

Direction comparison principle has problems when applied to wide-area backup protection (WABP): low sensitivity of direction-element because of collected small current or voltage, need of directional messages of all branches and message errors during transmission. In this paper, an improved WABP based on direction comparison principle and fault component current distribution is presented to solve the problems. Combining negative sequence with positive sequence, it selects the branch with maximum amplitude current connected to buses locally and communicates required direction messages to the Center. Then, the decision-making center determines the fault line through the changed elements of state matrix. The principle has strong endurance ability to high-impedance-fault, needs no information synchronization, and has better ability to identify the error message, reducing the influence of insufficient sensitivity or incorrect information on the relay protection. It has better adaptability to multi-terminal, loop network The simulation results show that the method promotes the safe of the grid.