| China's energy resources and economic development patterns determine that energy must be large-scale,long-distance transmission.Replacing coal by electricity,replacing oil by electricity and coming from afar has gradually become the consensus in the field of energy.Therefore,it is urgent to put forward a new transmission technology to solve the problems of insufficient transmission capacity,high loss rate and high comprehensive cost of existing transmission lines.Research on New Transmission Technology of Pipeline with New Polymer cement concrete as Insulation medium.It is very important to improve the transmission capacity,reduce the loss,improve the reliability and reduce the comprehensive cost of the transmission line.Taking the insulating material PCC for pipeline transmission as the research object,the formulation and preparation technology of PCC,the electrical properties and thermal aging properties of PCC were studied.By testing the product test of different formula and preparation technology of the PCC,to determine the optimal ratio of PCC material of Portland cement expansive agent 100,waterborne epoxy resin content of 10-14,than 0.55-0.6 water adhesive,defoaming agent dosage of 0.4,the optimal selection of preparation conditions of dry pressing.The electrical properties of PCC samples were studied.The dielectric loss factor and relative dielectric constant of PCC at room temperature were 0.062 and 5.62 respectively.With the increase of temperature,the relative dielectric constant of PCC sample decreases slightly,and the dielectric loss factor increases.The power frequency electrical strength and lightning impact breakdown strength of PCC samples are slightly lower than those of conventional crosslinked polyethylene,and the initial partial discharge discharge is180 PC.The thermal aging tests of PCC samples were carried out at three different temperatures and five cycles.Compared with the thermal aging,the dielectric properties of PCC samples changed with the temperature unchanged,but the relative dielectric constant decreased 15.79% and the dielectric loss factor increased 18.75%.The breakdown voltage and mechanical strength of PCC samples have been decreased,and the mechanical strength has decreased more quickly,before the electrical breakdown performance to the end of aging.The heat resistance grade of PCC was evaluated.The temperature index TI was 170.18 and the heatresistance grade was F grade 155 ?.The heat resistance of PCC was obviously superior.The PCC has large dielectric loss,high relative dielectric constant,low dielectric strength and excellent heat resistance of PCC.If it is used in large-capacity pipeline transmission,it can reduce the micro-pores and free water generated by silicate reaction,and adopt the dielectric property of cement-promoting material with little iron content. |
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