Study On Insulation Diagnosis Of10kv XLPE Cable Based On Pd And Dielectric Loss

With the rapid development of electric power infrastructure and the expansion of theurban distribution network, XLPE cable is more and more important in city distributionnetwork low and medium voltage grade. Once the cable line down, it will causeunpredictable outage loss. How to optimize the diagnosis for10kV XLPE cable insulation"health" is significant to grasping the operation status of the cable, making the correctmaintenance strategy, reducing non normal outage cable line, ensuring the operationreliability of significance.In this paper, the electrostatic field distribution of typical defects such as compoundboundary of cable accessory moistened, fracture steps in outer semiconducting layer andthe major insulation scratch etc are calculated by using ANSYS, with The harm ofquantitative analysis of these defects.Based on the simulation feseach on the changing ruleof the amplitude, frequency and pulse width in the process of cable partial discharge pulsesignal transmission, the equivalent circuit model of composite interface of cable joint withdamp defects in different degree is set up and simulation presents a method and typicalgraph based on TDR method to detect the defect of composite interface with damp.What’s more, Through the establishment of XLPE cable insulation dielectric lossmathematical model considering relaxation polarization process, The digital simulation ofinsulation defects is done which include several forms water branches of different length,densityand composite interface of cable accessory affected with damp.simultaneously somemethod and scope of application are put forward by using ultra-low frequency dielectricloss in the diagnosis of medium voltage cable insulation degradation.On the basis of theoretical analysis and simulation study, The field measurement of10kV XLPE cable insulation is conducted by using broadband partial discharge detection,offline OWTS test and localization, ultra-low frequency dielectric loss test and based ontime-domain reflection wave method to measure the pulse signal, and the sampling ofsuspected defect cable secondary survey and anatomy anlaysis are followed. Put forwardthe comprehensive10kV XLPE cable line insulation diagnosis method of framework andimplementation process, to providing reference for engineering application.