Abstract: With the increasing deployment of distributed power generation in distribution networks, the protection performance of traditional devices have been greatly affected..The massive access of distributed power sources makes the traditional distribution network no longer a radiation network, but a multi-power one, rendering traditional current protection in effective. A regional differential protection scheme suitable for large-scale distributed power generation in distribution networks is proposed to improve the reliability and rapidity of protection device. Each distribution line is equipped with a traditional differential protection as the main protection, while the minimum area differential protection is used as the backup protection for the line. This ensures that any fault can be cleared with an action delay of 0.15 seconds in the event of a fault in the distribution network line, thus minimizing outage range of the power system. The proposed regional differential backup protection strategy can reliably identify the minimum backup protection area without centralized deployment of the protection by the central equipment, and act promptly in case the main protection fails to operate. The simulation analysis results indicate that this scheme can adapt to complex distribution network structures and reliably isolate faults. Consequently, it can serve as a comprehensive protection scheme for distribution networks accessed by large-scale distributed power sources. The coordination between backup protection and main protection can not only ensure the rapidity and selectivity of protection, but also ensure the reliability of protection actions.