Regional Differential Backup Protection Suitable for the Collection Lines of Large-Scale Photovoltaic Stations

In recent years, the rapid expansion of large-scale photovoltaic (PV) power stations has necessitated intricate two-stage aggregation systems within stations, where thousands of PV generation units are consolidated via cables and overhead lines before reaching the booster station. Complexity in wiring poses challenges, as malfunctioning coordination of aggregation line protection post-fault can lead to misoperations, tripping non-faulty branches, expanding power outages, and hampering grid-connected efficiency. To enhance reliability and speed of protection, A regional differential backup protection tailored for aggregation lines in large PV stations is proposed in this paper. The traditional differential protection is set as the primary safeguard protection and minimal regional differential protection is set as backup protection. Our strategy, under limited communication constraints, reliably identifies the smallest backup protection zone and, in cases of primary protection refusal, swiftly isolates faults with minimal action scope and duration. MATLAB simulation validates its adaptability to complex PV station wiring, ensuring reliable fault isolation. The synergy between backup and primary protections ensures speed, selectivity, and reliability in protection operation.