Evaluation analysis of XLPE cable´s electrical condition

Nowadays, the cable is the major power transmission apparatus of urban distribution network, the running state of the cable has a direct relationship with reliability of power system. However, with the accumulation of XLPE cable´s laying length, the faults resulted by the cable show the increasing trend of multiple and frequency. Therefore, it´s of great concern by urban power supply companies that how to evaluate the cable´s electrical condition, develop scientific upkeep programs, and consequently achieve effective management for cable in different periods of running process. Firstly, we survey 10kV XLPE cables´ status of Guangzhou city and analyze the typical snag cases. Further, we collect seven cables which are out of service as well as their attachments, and perform electrical testing on them. The testing results show that the insulation resistance, dielectric loss tangent and partial discharge can reflect cable´s insulating state in some extent. The cable´s running state can be effectively assessed by combining all the testing results. Based on the results and National Standard GB12706, we finally establish a cable condition assessment model, and apply it for running state appraising of new and aged cables. The appraising results validate the effectiveness of the model for judgments and estimates for the change of cable´s operation states.