Analysis of the Depth of Positive Sequence Voltage Sags in Distribution Network Faults and Their Effects on New Energy-Type Equipment

With the proposal of the “double carbon” goal, the proportion of distributed generation in the power grid is gradually increasing, distribution network faults will lead to voltage sags, which may make the distributed generation into the low voltage ride-through process or even off-grid, and sensitive loads to work abnormally, affecting the normal operation of the power grid. This paper takes a typical radial distribution network as an example and analyzes the depth of voltage sags at new energy-type equipment points of common coupling (PCC) in different grounding methods and at different locations where various faults with transition resistance occur. Theoretical analysis and PSCAD/EMTDC simulation analysis results show that the closer the fault is to the PCC, the deeper the positive sequence voltage sag at the PCC, and the lowest positive sequence voltage is lower than 0.2 pu in a three-phase short circuit, and the obtained conclusions provide some guidance for the fault voltage compensation strategy such as Dynamic Voltage Restorer (DVR).