A unified adaptive scheme for fault location and relay coordination in Smart Grids

Abstract

This paper presents an adaptive protection scheme for distribution networks with distributed generation. The proposed system offers the novelty of being able to both locate the zone in which the fault has occurred and adapt the setting parameters of the relays involved in the process for each network condition. The unified adaptive system can be applied for fault detection in both the main feeder and lateral branches, taking into account the variable conditions of the distributed power generation and power demand. The setting of the relays' parameters responsible for the coordination of the zone protection is done by optimizing three degrees of freedom using mixed-integer nonlinear optimization techniques. The proposed adaptive protection scheme is validated in a standard distribution test feeder to prove its capability to locate faults in both main and lateral branches and optimize the performance of the involved relays under variable generation conditions, different fault types and different fault locations. The adaptive protection scheme reduces relay operating time significantly compared to classical and linear relay techniques.