Research On Fault Aging Characteristics And Life Evaluation Of XLPE Cable

As an indispensable carrier for electric energy transmission,XLPE cable has gradually replaced other cables as the main equipment of the current high-voltage AC / DC transmission grid.The XLPE cables in operation are mainly subjected to electrical and thermal stress,resulting in a decrease in insulation strength,there will even be problems with insulation failure and grid accidents.Therefore,problem of the variation rule of the insulation characteristic quantity and the life evaluation method caused by the tiny faults in the XLPE cable are studied in this paper.ZR-YJV223-15 kV type cable is selected as the experimental sample in this paper,focusing on the study of the change law of characteristic quantities such as dielectric loss factor and polarization index.Testing and analysing the insulation characteristic quantities of cables with different faulty types during the combined electrothermal aging process,statistical analysis and OriginPro8 software and other scientific methods are used to systematically analyze and process the experimental data,obtaining the differences in the evolution of the characteristic quantities affected by different types of faults,and at the same time finding out the correlation between the characteristic quantities.To revealing the change law of rupture elongation of XLPE cables under different thermal aging temperatures,a series of mechanical performance experiments were carried out.And using the principle of time-temperature superposition to carry out related operations to obtain the parameter b of Arrehenius equation and the real value of activation energy;By expanding the ladder In the step-up experimental study,the real value of the electrical aging life index n of this type of cable was obtained,and the reliability of the experimental results was verified by the Weibull distribution curve;Based on the real values of b and n,the Simoni model and Matlab software were used to build a the three-dimensional evaluation chart of the service life of the XLPE cable combined with electric and temperature,and a method for evaluating the remaining life of the XLPE cable at a certain temperature and a certain voltage is proposed.A new method for judging the cause of similar insulation aging of XLPE cables is provided according to the research results in this paper.At the same time,thethree-dimensional evaluation chart method can quantitatively evaluate the remaining life of XLPE cables,providing accurate timing for maintenance and ensuring safe and reliable operation of the power grid.