Research Of Test Method For Completion Acceptance Of High-voltage Power Cable

With the development of economy and society,high voltage cross-linked polyethylene(XLPE)insulated cable has become an important component of urban transmission network.Ensuring the safe and stable operation of high voltage cable lines is of great significance.Completion acceptance test of high voltage cable is used to detect defects before operation,which is an important step to avoid high voltage cable lines running with hidden defects.High voltage cable fault is mainly caused by small defects caused by damage in engineering construction and bad installation of cable accessories.Minor defects will give rise to partial discharge in operation,leading to irreversible damage and breakdown of cable insulation.AC voltage withstand test in high voltage cable completion acceptance test can detect serious defects,but not effective to detect minor defects,leading to high voltage cable running with hidden defects.This thesis proposes an integrated detection technology for high voltage cables that distributed partial discharge detection is carried out during AC voltage withstand test.Through partial discharge detection of multiple positions on high voltage cable,small defects caused by bad installation of accessories and damage in engineering construction can be found,improving high voltage cable completion acceptance test method and reducing risk of high-voltage cable running with hidden defects.After introducing the technical principle,technical method and adoption process of the integrated detection technology,this thesis studied the mechanism of voltage and test time effects on defect recognition.According to the equipment parameter requirements determined by the length,capacitance range of high voltage cables and the number of cable joints and detection positions,device for AC voltage withstand test and distributed partial discharge detection were designed and applied during high voltage cable completion acceptance test.With anatomy of high voltage cables,it is proved that the integrated detection technology of AC voltage withstand test and distributed PD detection can effectively detect defects caused by damage in engineering construction and bad accessories installation of high-voltage cables.Compared the number of cable lines found with defects in completion acceptance test and malfunctions caused by defects in three years before application of the method in NanJing with the number in three years after application,the method was proved to be effective in reducing high voltage cables running with hidden defects.