Influence Of Voltage Stabilizer On AC Insulation Properties Of XLPE

Crosslinked polyethylene(XLPE)as the main material for insulation of high voltage power cable,Determine the service life of power cables and adapt to the working environment.With the development of economy and society,People put forward higher requirements on the withstand voltage level,and the electrical tree phenomenon of XLPE is an important factor that causes the insulation material to be aged and eventually breakdown.Based on the above reasons,In order to improve the service life and working voltage grade of the XLPE insulated high voltage cable,Need to further improve the XLPE's electrical resistance of branches,Adding voltage stabilizer to XLPE has become one of the more efficient methods.In this paper,the properties of several aromatic ketones as voltage stabilizers are studied.The research work is of engineering value and theoretical significance.In this paper,four aromatic compounds,including light stabilizer UV-531,photoinitiator ITX,benzil and 4,4'-Dimethoxybenzil were used as voltage stabilizer and melt blended into polyethylene(PE)to prepare XLPE materials containing different voltage stabilizers.With pure XLPE as a reference,the effects of different voltage stabilizers on the electrical tree initiation voltage,electrical tree growth characteristic,AC breakdown strength,relative dielectric constant and loss characteristic of XLPE were investigated.The experiments of electric tree priming and AC breakdown were tested at different temperatures to explore the influence of temperature on them.Experimental results indicated that 4,4'-Dimethoxybenzil can increase the electrical tree initiation voltage of XLPE by 49%,At the same time,it can also slow down the growth rate of the electric branches to a certain extent.When the temperature rises,Five kinds of materials,the starting voltage of the electrical branches are significantly decreased,It can be seen that the temperature has a significant influence on the electrical branch phenomenon of the material.As the temperature increased,anisyl anisyl added to the electrical branch of XLPE still had a better inhibition effect;At room temperature,the four kinds of voltage stabilizer can improve the AC breakdown strength of XLPE to varying degrees,the UV-531/XLPE increased by 8.6% and ITX/XLPE by 9.4%,When the temperature exceeds 50°C,the four kinds of voltage stabilizers have poor ability to improve the electric strength of XLPE and the starting voltage of the branch.The dielectric spectroscopy test results indicated that the addition of voltage stabilizer will increase the dielectric constant and loss tangent of XLPE,but under the power frequency voltage,except for ITX,the other three voltage stabilizers do not affect the normal use of materials,within the acceptable range.In addition,theoretical calculation shows that the role of voltage stabilizers is closely related to the electron gap,electron affinity and ionization energy parameters of aromatic ketones.