Adaptive protection configuration of intelligent sectionalizing switches for 220 kV transmission lines

To solve weak infeed, bidirectional current contribution and transient disturbance in 220 kV transmission lines with high-penetration distributed photovoltaic generation, an adaptive protection configuration for intelligent sectionalizing switches is proposed. The influence of inverter-interfaced photovoltaic units, series compensation and line distributed capacitance on measured current, voltage and impedance is analyzed, and a fault-current model with photovoltaic penetration is established. Then a BP neural-network-based phase-segregated differential protection and an improved-particle-swarm-based distance protection are configured. The former updates the restraint coefficient with real-time states, while the latter optimizes zone-I and zone-II impedance settings online. A PSCAD/EMTDC model is built for different penetration levels, fault positions and fault types. Results show that the differential protection operates within 21-25 ms without maloperation at 80% photovoltaic penetration; distance protection keeps impedance error below 3% and operates within 28-35 ms. The configuration improves fault identification, section location and rapid isolation for 220 kV lines with large-scale photovoltaic access.