In power systems, due to the large number of outgoing lines on medium and low-voltage buses,frequent operations, the close distance between three-phase conductors and the ground, susceptiblityto damage from small animals, inferior equipment manufacturing quality compared to high-voltageequipment, insulation aging and mechanical wear of equipment, harsh operating conditions,changes in system operating conditions, and human operational errors, the fallure rate of medlumand low-voltage buses Is signlficantly higher than that of high-voltage and extra-high voltage buses.However, for a long time, insufficlent attention has been pald to the protection of medium and low-voltage buses. Most systems rely on the backup overcurrent protection of upstream components (such astransformers) to clear bus short-circuit faults, resulting in prolonged fault clearing times. This often leadsto the development and escalation of faults, causing substantial economic losses According to reports,hundreds of medlum-voltage handcart switchgear cabinets are burned out annually In China's powersystems. The primary reason Is the lack of dedicated medlum and low-voltage bus protection, which falls toquickly clear faults