Intelligent Controlled Distributed Generator System for P-Q Control and Islanding Detection

An intelligent controlled distributed generator (DG) system is proposed for the tracking control and islanding detection in this study. First, a DC power supply with a DC/AC power inverter is adopted to emulate a DG system for the tracking control of active power and reactive power outputs. Moreover, a novel active islanding detection method is proposed for the DG system to meet stringent standard requirements for interconnection with the power grid. The proposed active islanding detection method is based on injecting a disturbance signal into the DG system through the d-axis current which leads to a frequency deviation at the terminal of the RLC load when the power grid is disconnected. The feasibility of the proposed active islanding detection method is evaluated under the UL1741 anti-islanding test configuration. Furthermore, in order to improve the tracking control of the active power and reactive power outputs of the inverter-based DG system, and to further improve the performance of the active islanding detection method, two probabilistic fuzzy neural network (PFNN) controllers are adopted to replace the conventional proportional-integral (PI) controllers. In addition, the network structure and the online learning algorithm of the adopted PFNN are introduced in detail. Finally, the effectiveness and feasibility of the tracking control and the proposed active islanding detection method using PFNN controllers are verified with experimental results.