Abstract:In order to adapt to the low current fault characteristic of island operation, the protection of the distributed power island operation is different from the protection of the parallel operation. But as the increase of the frequency of input and resection of the distributed power, the set values of the protection must also frequently convert between different protection methods. So sequence components distance protection based on power frequency variation is put forward. Taking the short circuit fault of negative sequence voltage as an example, this paper analyzes the distribution of voltage, obtains the operating criterion of negative sequence and zero sequence relay, and builds the simulation module of negative sequence and zero sequence relay in the MATLAB. In the environment of grid-connected and islanding operation respectively, the simulation analysis of the action of the proposed method in the situation of different fault distance and transition resistance is conducted, which verifies its reliability.