Short - Circuit Current Limitation of 750kV Power Grid Based on Distributed Current Limiting Device

To effectively address the issue of excessive short-circuit current in the 750kV power grid of Ningxia, this paper proposes a method for limiting short-circuit current based on distributed current-limiting devices. This method is theoretically grounded in the use of SF6 high-speed switches to restrict short-circuit currents. A simulation model for evaluating short-circuit currents in Ningxia's 750kV power grid with distributed current limiting devices is established. The model scans the short-circuit currents across the entire grid, evaluates the sensitivity of the alternating current (AC) component of short-circuit currents in branches of over-standard 750kV stations, and determines the final configuration scheme for distributed current limiting devices by targeting minimum short-circuit current and minimum operational risk while considering economic principles. On this basis, the impact of the limiting measures on the DC component of the short-circuit current is further analyzed. Simulation results show that the current limiting measures based on distributed current limiting devices can effectively solve the problem of excessive short-circuit currents in Ningxia's 750kV power grid system, with minimal impact on the DC component of short-circuit currents.