Protection Strategy of Islanded Micro-Grid Based on Short-Time Energy Segment

Abstract

Islanded micro-grid’s fault status and normal state are difficult to be distinguished, because of the small inertia of the micro-grid system and the impact of the inverter-based generators. In the viewpoint of energy, this paper presents a feature that can reflect the energy magnitude of the feeder, called short-time energy segment (SES). Hence, a new adaptive protection strategy for the islanded micro-grid is proposed based on analysis of the fault current and SES; and the fault location is obtained by the information of the fault current. Finally, the islanded micro-grid protection strategy is achieved combining the method of fault detection and fault location. An islanded micro-grid model is simulated in the DIgSILENT software, and simulated data is calculated in MATLAB software. Theory and simulation results demonstrate that the proposed method of fault detection and fault location can correctly detect the islanded micro-grid’s fault state and fault feeder, and effectively enhance the security and stability of the islanded micro-grid.