Study On Typical Defect Partial Discharge Of 10kV Cable Joint

Influenced by electric and magnetic fields, heat, light, moisture and other factors, Power cable will inevitably occur insulation aging in the energy transfer process, reduce the insulation performance, finally resulting in partial discharge(PD). Although order of magnitude is not large, the PD will exacerbate the aging of the insulation and ultimately cause dielectric breakdown.Statistics and study show that the cable fault are mainly caused by outside force damage and cable joint fault and that the cable joint fault was mainly caused by defective connector during the installation process. The defective cable connector go into operation lead to electric field concentration in the defective portion and cause the partial discharge(PD), discharge development eventually lead to joint breakdown. Therefore, the analysis of partial discharge characteristics of typical defects cable connector types has great significance for 10 kV network cable joint quality control and the reliability of the power supply.With the statistical analysis of the actual cases, the paper identified 7 types of typical cable joint defects and builds their finite element simulation models to calculate the change of electric field in defective portion. The simulation result show that all types of defects can lead to the electric field raise, but the defects related to the semiconductor layer changed more than others. Finally make 4 types of artificial typical cable joint defects and put to the OWTS test then analyze test results. The test and simulation results prove OWTS test can effectively detect most cable joint defect, but for some defects(such as primary insulation scratched) detection still has some limitations.