A Novel Active Current Disturbance Method Based on Discrete Wavelet Analysis

Islanding detection method of active current disturbances in three-phase photovoltaic-to-grid system makes the common connection point (PCC) voltage appear high frequency components on account of load variation, the surge current occurrence and other factors. This high frequency component cause islands misjudgment. Using Db10 wavelet to detect and analysis PCC’s voltage high-frequency components on real-time based on the active current disturbances principle. And selecting an effective wavelet domain values as the voltage harmonic detection amount islanding detection. Islands simulation test is conducted in the case of the inverter output power and load input power to match, the test results show that this method can quickly detect islanding, and effectively prevent pseudo-island phenomenon of false positives.