Applicability Analysis of Distance Protection in AC/DC Hybrid Power Grid

In the context of the AC/DC hybrid power grid with wind farms, the applicability of distance protection is analyzed, and a polygonal characteristic adaptive distance protection is proposed. When an AC line fails, its fault characteristics are affected by the Modular Multilevel Converter (MMC) fault ride-through control strategy. The fault current characteristics provided by MMC are very different from traditional synchronous generators. Based on the analysis of the adaptability of traditional distance protection, the additional impedance angle is obtained by using the current information of the protection installations on both sides of the line, and modify the setting value of distance protection, which solved the problem that the distance protection could not operate correctly The correctness of the method is verified by RTDS simulation