Islanding Detection for Distributed Generation

The paper analyzes the performance of a ROCOF relay and looks at the factors that affect its detection capability, such as load type and the impact of load power factors. It also considers how ROCOF can maloperate during system transients. The later section of this paper describes a new LOM detection technique based on a GPS synchronized phasor measurement system that compares the angular difference between the utility network voltage phasors and the distributed generator voltage phasors. The performance of the proposed technique is shown to be more reliable than ROCOF.