Research on Adaptive and Enhanced Longitudinal Protection Method of Intelligent Distribution Network

With a vast amount of Distributed generation (DG) such as distributed photovoltaic (PV) connected to the grid, the impact of DG on the fault properties of distribution network feeders can not be ignored. An adaptive and enhanced longitudinal protection method considering the operating state of intelligent distribution network is provided. The strategy uses the variation of current amplitude on either sides to construct the action of the protection criterion, and improves the sensitivity of high resistance fault by adaptive enhancement factor. In addition, the protection braking quantity is constructed by the current phase difference function on either sides to improve the reliability in closed-loop operation.