The external cable partial discharge monitoring system adopts a modular design. It utilizes high-frequency current sensors installed on the grounding wires of cable joints to capture the partial discharge pulse current signals from both the cable body and the joints. These signals are then transmitted to the data collector via coaxial cables. After undergoing amplification, filtering, analog-to-digital conversion, and comparative analysis with the database, the processed signals are sent to the remote backend through optical fibers. The calculated discharge information is written into the database and simultaneously displayed on the software panel of the monitoring system.