Optimization of time-sharing over-current protection setting value for distribution network with decentralized access of distributed power supply

Abstract

Distributed generator (DG) decentralized access to the distribution network, so that the current characteristics presented during the fault period are different from the traditional distribution network, and the current characteristics are more complicated. The variation of DG's output in different time periods leads to the inability of stage current protection to accurately discriminate. In this paper, firstly, the low-voltage ride-through control strategy is considered, and the current characteristic model of DG output port is established. Then, the current characteristics during the fault period after decentralized access of multiple DGs are analyzed. The optimization scheme of adjusting the protection value according to the DG parameters by time period is proposed by combining the output information of DG in different time periods. Finally, it is verified through examples that the proposed protection scheme can enhance the protection range of section I and significantly improve the sensitivity of section II, which has practical application value.