Study On Electrical Aging Characteristics Of Silicone Rubber Matrix Composites

In the DC cable system,the field intensity distribution in the insulation structure is inversely proportional to the material volume conductivity when the attachment is steady.In the XLPE insulated high voltage DC cable terminal,the electrical conductivity of the silicone rubber reinforced insulation is less than the cable XLPE insulation,and the high electric field strength zone in the high pressure DC cable terminal with the ordinary silicone rubber as the enhanced insulation.The field is located in the silicone rubber enhanced insulation.In general,the breakdown strength of the HVDC cable XLPE insulation is far greater than that of the silicone rubber insulation.Therefore,the electric field distribution in the XLPE insulated high voltage DC cable terminal with the common silicone rubber as the enhanced insulation is not reasonable.The edge material can be a good solution to this problem.Due to the long-term operation of the cable in the HVDC electric field,the insulation strength of the insulating material is reduced and the attachment insulation is easily penetrated,and the stability of the HVDC cable operation is reduced,and the normal power supply of the whole transmission system is endangered.Therefore,the electrical aging resistance of insulation materials is an important factor determining the overall insulation capacity of cable accessories.In this dissertation,silicon rubber nanocomposites with nonlinear conductivity are made from solid silicon rubber as matrix,nano graphite and nano carbon black as filler.The material and pure silicone rubber are used for electrical aging test.The pure silicone rubber and silicone rubber nanocomposite after the aging and aging time of 720 h,1440h and 2160 h are tested.The electrical properties,DC breakdown characteristics and space charge characteristics of the composite materials are used to analyze the electrical properties of pure silicon rubber and silicone rubber nanocomposites after different aging time,and compare them.The results show that in the process of electrical aging,after the same aging time,the conductivity of the two materials at 30,50 and 70 centigrade increases with the increase of the aging time,and the growth degree is similar,and with the increase of the test temperature,silicon is increased.The electrical conductivity of rubber nanocomposites and pure silicone rubber increases.At the temperature of 30,50 and 70,the breakdown field strength of the two materials decreased with the increase of aging time,and the decrease trend was basically the same,and the breakdown field strength of the silicon rubber nanocomposites and pure silicone rubber decreased with the increase of the test temperature.The amount of space charge accumulated in the two kinds of materials increases with the increase of aging time,and the increase trend is basically the same,and after the same aging time,the amount of space charge in the internal accumulation of the silicon rubber nanocomposites is less than that of the pure silicon rubber.The above experiments show that nano composite silicone rubber has the same electrical resistance property as pure silicone rubber.