In order to solve the problem of difficulty in relay protection of urban distribution network with short power supply radius

a scheme based on current limiting difference and high selectivity relay protection is proposed. The substation outlet circuit breaker and the loop switches are equipped with current limiting protection devices. When a phase-to-phase short-circuit fault occurs

the current limiting protection device of outlet circuit breaker quickly limits the current and cooperates with the protection device in the feeder segmentation switch to achieve multi-level differential relay protection. In the case of a permanent fault

the loop switch configures the current limiting protection device to achieve the isolation of the fault area and restoration of power in the sound area under current limiting conditions. The composition and working principles of the current limiting protection device are discussed in detail using examples and the parameter setting method is emphasized. The analysis results show that the proposed method can effectively reduce the short-circuit current level and the damage to the equipment during fault handling and is applicable not only to overhead distribution networks but also to cable distribution networks.