An Fault Detection Strategy of Hybrid AC/DC Microgrids Based on HHT Theory

With the development of green energy, AC/DC microgrids become popular for integrating more renewable energy sources. However, comparing to traditional AC distribution grid, the grid fault characteristics become more complex in hybrid AC/DC microgrids with the coupling of AC and DC part. Therefore, the existing fault detection strategy of traditional AC grid is not suitable for AC/DC microgrids. An fault detection strategy of hybrid AC/DC microgrids based on Hilbert-Huang Transformer (HHT) spectrum theory is proposed in this paper, which could use the obvious fault characteristics before blocking the converters' IGBTs and maintain the rapidity and accuracy for fault detection of AC/DC microgrid. Through simulation verification, the scheme can realize fault detection and identification within 2 ms before blocking the IGBTs.