Research And Application Of High-voltage Cable Distributed Partial Discharge Detection Technology Based On Ac Withstand Voltage

According the rapid development of national economy and urbanization construction,the requirement of power supply is growing in the aspect of reliability and stability.Considering the munic ipal planning,environmental effect and personal safety princip les,the utilization ratio of power cable is increased dramatically for city power transmission.System capacitive current is improved with the power cable usage popularizing,which prevents the ground fault arc extinguished,amplifies fault area,and leads to fatal accident.It is very difficult to find out the inter insulation defect of the long distance power cable laid in the specific tunnel or beneath the ground.In recent years,severe accident occurs frequently due to the inter insulation defect,poor process control of manufacturing and installation for power cables.Therefore,a thorough detect for power cables should be taken before put into operation,trying to avoid any defective equipment connected into the power grid.The research of a partial discharge test method is carried on to solve the problem aforesaid in this dissertation,based on AC withstand voltage technique for detecting the possible insulation defect ins ide the power cable or in the jointed parts.In addition,a distributed partial discharge detect system is designed based on the high-frequency impulse detective method.Wireless information transmission and synchronization technique is utilized to collect signals from individual detective units.Fault location and pattern recognization is performed by artific ial neutral network functional module in the supervisory control system.The major contents include:1)discussing the principle of partial discharge for power cables,and the transmission features of the discharge signal ins ide power cables;establishing mathematical models for discharge process,power cable circuit,and discharge signal transmission;2)designing a distributed partial discharge detective sys tem based on AC withstand voltage technique to detect the inter insulation defects in the power cable or the jointed parts,and utilizing wireless transmission and synchronization technique to locate the fault position;3)collecting and analysing feature of partial discharge signa ls,establishing a feature database for typical defect spectrogram,and performing pattern reorganization for the insulation defect inside the power cable or the jointed parts by artificial neutral networks.