Adaptive Protection System Using Neutral Currents Studies and Load Estimation

Abstract

Distribution grids become increasingly dynamic due to grid automation, increased distributed energy resources and continuous load variations. Faced with these conditions, distribution utilities have difficulty keeping their protection system operating at an optimal point for their entire distribution system. As a solution to ease protection settings calculation throughout the utility operating area, common protection methodologies are used, which consist in generic oversized parameters. Without the optimal design of protection parameters, distribution utilities are constantly facing fault detection problems for broken cables or high impedance faults. This work presents an Adaptive Protection System, designed to learn the grid load profile and adapt neutral overcurrent protections, in order to make the protection more sensitive. The proposed system uses two types of adaptive protection, Planned and Emergency, so that distribution protection can always be updated, even in the event of load growth in the grid, distributed energy resources increase, or even after a load-switching event on the distribution system. The article focuses on a new philosophy of autonomous and dynamic protection adjustments, as the distribution grid undergoes through changes.