Development of online monitoring system for 1500 V ethylene–propylene–rubber DC feeder cable of Shanghai urban rail transit

The form of ethylene-propylene-rubber DC feeder cable faults can be attributed to insulation aging and mechanical insulation crack, while integrating the DC leakage current (DLC) signal, and track discharge (TD) signal could effectively detect such defaults online. Further research results about an online monitoring system will be introduced, which is developed to evaluate the insulation of DC feeder cable in the traction substation of the Shanghai urban rail transit. The monitoring system adopts distributed structure and is made up of TD sensors, DLC sensors, data acquisition system and monitoring central with faulty diagnosis expert system. The experiments were carried out, both under the condition that the insulation of the DC feeder cables is in the good and fault status, in the laboratory, respectively, to verify the feasibility of the system. The results indicated that the system can forecast the insulation aging fault and the crack fault of the feeder cable. Furthermore, the system was also installed in the field and put in the real operation and it run stably and reliably in the field, and the diagnostic results were consistent with the actual circumstances.