ACTIVE FREQUENCY DRIFT ISLANDING DETECTION ALGORITHM FOR SINGLE-PHASE PHOTOVOLTAIC GRID-CONNECTED INVERTER

Abstract

As the photovoltaic generation industry rises, the requirements for the reliability of photovoltaic power generation have become higher.  The traditional active frequency drift islanding detection algorithm has advantages of simple operation, easy implementation, high speed and high detection rate of island; however, the large impact of the algorithm on the detection performance can bring harmonic pollution to power grid and even induce voltage flicker and instability of the network system. When multiple photovoltaic systems work in the form of grid connection, frequency drift appears and the effects cancel each other out, leading to the appearance of non-detection zones.  This study simulated a positive feedback islanding detection method using SIMULINK and proposed a novel active positive feedback active frequency drift detection method that could realize frequency drift by increasing disturbance with piecewise function based on the drawbacks of the active frequency drift islanding detection algorithm.  Finally, the advantages of the system in resisting islanding were verified through computer simulation.