Micro-grid connected/islanding operation based on wind and PV hybrid power system

The micro-grid technology that integrates distributed generations, energy storage element and loads is an effective approach to solve the interconnection of large-scale distributed generations with power grid. Wind and solar can be complementary to each other in time, therefore wind and PV hybrid power system could make full use of clean energy and have high reliability. Smooth switching between grid-connected mode and islanding mode is important to micro-grid stable operation. In this paper a micro-grid model based on wind and PV hybrid power system is built with DigSILENT/PowerFactory. The improved control strategy of P-Q control and droop control combination is proposed and the transition state simulation as to the micro-grid mode switching process is carried out. The result shows that this advanced control strategy can ensure power balance and reasonable power assignment, it also could keep connected bus voltage and micro-grid frequency stable during micro-grid mode switching.