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Wang X.,Xi'an Jiaotong University | Yao H.,Xi'an Jiaotong University | Wu K.,Xi'an Jiaotong University | Liu S.,Shanghai Jiejin Advanced Electro material Co. | And 2 more authors.
Gaodianya Jishu/High Voltage Engineering | Year: 2014

In the installation of cable accessory, the interface between cable accessory insulation and cable insulation is usually coated evenly by silicone grease. However, the effect of different kinds of silicone greases on interface characteristics is barely reported. Therefore, using two common kinds of silicone greases in industrial applications, namely, the common silicone grease (CSG) and the fluorinated silicone grease (FSG), we researched the effect of silicone grease coating on the space charge characteristics of the interface between cross-linked polyethylene (XLPE) and silicone rubber (SR), which was measured by using the pulsed electroacoustic method (PEA). The swelling effect of silicone grease on SR was also investigated through mechanical tensile experiments. The tests show that, compared with CSG, the FSG coated interface of XLPE/SR is easier to have charge accumulated for its stronger electronegativity. Both CSG and FSG have swelling effect on SR, which will make the positive interface charge transfer inwardly into SR; meanwhile after aging, the CSG coated SR shows a more dramatic decline in mechanical property.


Wang X.,Xi'an Jiaotong University | Wang C.,Xi'an Jiaotong University | Wu K.,Xi'an Jiaotong University | Liu S.,Shanghai Jiejin Advanced Electro Material Company | Peng J.,Shanghai Jiejin Advanced Electro Material Company
Hsi-An Chiao Tung Ta Hsueh/Journal of Xi'an Jiaotong University | Year: 2013

Considering the effects of expansion and deformation after accessory installation on the reliability of cable accessory in service, a new optimal design scheme was proposed for high voltage cable accessory. The deformation and displacement equations of cable accessory during expansion were deduced in detail with the theory of elasticity, then the production structure was obtained via the optimized structure relaxation in an expansive state to ensure the optimum electrical field after accessory installation. According to the structure parameters of the domestic 35 kV cold shrinkage cable, the effects on electrical field distribution of cable accessory were analyzed by comparing the proposed and the traditional design schemes, then the deformation and recovery method were verified. The simulation and calculation show that the displacement nonlinearly decreases from inside to outside of the insulation during cable accessory expansion; the expanded accessory leads to a thinner main insulation thickness and a shorter length; the angle of stress cone and the end shape of high voltage shielding tube deviate from the design structure, which results in enhanced electric field at the interface and the end of HV shielding tube.


Wang X.,Xi'an Jiaotong University | Wang C.,Xi'an Jiaotong University | Wu K.,Xi'an Jiaotong University | Tu D.,Xi'an Jiaotong University | And 2 more authors.
IEEE Transactions on Dielectrics and Electrical Insulation | Year: 2014

Cable accessory always fits cable with a shrink range in order to ensure a certain interface pressure in the actual use, so cable accessory keeps in the expansive state after installation. But the expanded accessory will lead to not only a thinner insulation thickness and a shorter length but also a possible problem in the accessory, as the angle of stress cone and the shape at end of high voltage (HV) shielding tube may far deviate from the original design structure. This will be a vital threat to the reliability of cable accessory in service. In this paper, an improved design scheme for HV cable accessories was proposed to ensure the optimum electrical design after installation. The key process was the deduction of deformation and displacement equations of cable accessory during expansion by the theory of elastic mechanics. As joints are always much weaker than terminations in the cable system, the case studies were conducted only on cable joints in this paper, and the electrical fields were calculated to evaluate their performances. By contrast with the electrical field distributions before and after improvements, the results show that the expansion will not only change the joint structure but also aggravate the electrical fields at the interface or in the bulk of the joint. At last, a comparison was made on an actual cable joint which kept in the expansive or relaxation state, so as to verify the correction of the deformation and recovery equations proposed in this paper. This improved design scheme can also be applied for termination design, especially be great helpful for the higher or extra HV cable accessories' manufacture and the long-term operation safety. © 1994-2012 IEEE.

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