Donghui Yang

To address the severe physical wear of actual circuit breakers, limited logic verification under complex operating conditions, and maintenance scheduling conflicts during operational testing in power systems, this paper presents a portable auxiliary verification device for relay protection based on LoRa spread-spectrum technology. The device adopts a distributed modular architecture consisting of a master unit and multiple slave units, with STM32 MCU and LoRa communication serving as the hardware core. Circuit breaker simulator logic circuits are employed to replace the physical operation of actual high-voltage circuit breakers during testing. A dedicated software platform provides system management, real-time online monitoring, and historical data query and export functions. Experimental results indicate that the proposed device can accurately reproduce the state information of multiple circuit breakers, enabling complex logic verification, including automatic bus transfer (ABT) and busbar protection, without de-energizing primary equipment. Consequently, routine substation maintenance efficiency is significantly improved while operational risks are effectively reduced.