A Current Differential Protection Scheme Based on Q-axis Component for Distribution Networks

With the rise of the penetration rate of distributed generators (DGs) in the distribution grid, the traditional radial distribution grid is becoming an active distribution network (ADN). Since the fault characteristics of inverter-interfaced distributed generators (IIDGs) are different from those of traditional rotating type distributed generators (RTDGs), conventional protection schemes face huge challenges in active distribution networks with IIDGs. This paper first analyzes the current output characteristics of IIDGs under fault conditions, and then proposes a novel current differential protection method based on the q-axis component. Finally, the validity of the proposed protection scheme was verified by the simulation model built in PSCAD platform.