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Prospective authors are requested to submit new, unpublished manuscripts for inclusion in the upcoming event described in this call for papers. We are pleased to announce that the June 2014 issue of the IEEE Transactions on Dielectrics and Electrical Insulation (TDEI) will be dedicated to recognize and celebrate the 60th Anniversary of Electrical Insulation and Dielectric Research and Development in China. [ABSTRACT FROM PUBLISHER]

The ?1100 kV UHVDC wall bushing is the important power equipment in the ?1100 kV DC power transmission project of China. However, the reported literatures rarely mention its design method and the optimization of its insulation structure. In this paper, two specific designing schemes including the resin impregnated paper (RIP) condenser and the metalshielded core have been both adopted in the design of the wall bushing. Moreover, the actual operating environment and the rated parameters of the ?1100 kV UHVDC wall bushing have been analyzed in detail. Then, the nonlinear finite element method (FEM) analysis has been applied in the three-dimensional electric stress simulation of the UHVDC wall bushing. The electric field and temperature dependencies of the composite insulation used in the wall bushing have been taken into account. The E-field simulation results indicate that with the RIP condenser, the potential and electric field distribution can be much more uniform along the composite insulator of the bushing. Therefore, the compact design of the wall bushing can be obtained by this designing scheme. On the other hand, with the type of the metal-shielded core, the high E-field strength areas are mainly concentrated on the metal shield and the outer grading ring of the wall bushing. Therefore, the nonlinear FEM was applied in the structure optimization of the internal metal-shielded system used in the wall bushing. Finally, the maximum E-field strength of the wall bushing can meet the control requirement. Based on the simulation results and the optimization structure, the ?660 kV scaled prototype of the UHVDC wall bushing has been produced and passed through all the type tests according to the IEC 62199. The feasibility of the design of the ?1100 kV UHVDC wall bushing has been verified. This paper can provide the theoretical guidelines for the design, manufacture and operation of the UHVDC wall bushing. [ABSTRACT FROM AUTHOR]

Room temperature vulcanized (RTV) silicone rubber is a type of anti-pollution flashover coating which has been widely used in China. Featuring good hydrophobicity and adhesive property, RTV coatings are applied to insulators to increase the pollution flashover voltage of insulator strings. However, compared with high temperature vulcanized (HTV) silicone rubber used in composite insulators, RTV coatings are less durable in field operation. In this paper, investigation and experiments were conducted on some RTV coated insulators from Shanxi province and Guangdong province respectively. All the insulators have been in operation for about 6 years and the RTV coatings applied are produced by the same manufacturer. It is found that the performances of RTV coated insulators in Shanxi province are much better than those in Guangdong province. Phenomena such as chalking, color fading and peeling off were observed on RTV coated insulators from Guangdong whereas only slight loss of adhesion property and hydrophobicity were observed on insulators from Shanxi province. Micro structural analysis and macro performance tests were conducted on different positions of collected insulators and it is concluded that operation environment, especially humidity, have great impact on the operation performance of RTV coated insulators. [ABSTRACT FROM PUBLISHER]

This paper attempts to address the influence of sugar as a contaminant on outdoor insulation characteristics of insulators in a substation. Strong discharge activity was occurred under relative humidity less than 80% on insulators in a 500 kV substation at south China. A preliminary viewpoint that sugar as a contaminant leads to this strong discharge was drawn by investigating pollution sources around the substation and analyzing pollution layer conditions of discharged insulators. In order to further confirming this viewpoint and proposing the appropriate solutions for avoiding this discharge activity, the outward appearance, the surface conductivity, the discharge inception voltage and the flashover voltage of glass insulator and room temperature vulcanized (RTV) coated insulator under sugary and non-sugary contamination were investigated in detail in the lab. Furthermore, the hydrophobicity and hydrophobicity transference of RTV coated insulator were also investigated. The research results show that sugary contamination is very absorbent and viscous, outdoor insulation characteristics of insulators covered with sugary contamination are worse than that covered with non-sugary contamination, but outdoor insulation characteristics of RTV coated insulator covered with sugary contamination is still better than that of non-RTV coating insulator with non-sugary contamination. So it is still a specific solution to inhibit the discharge activity of insulators in the substation by spraying RTV coating. Of course, removing the sugar canes themselves from this area is the best solution. [ABSTRACT FROM PUBLISHER]

On the background of the peculiar technology problems with the external insulation of UHV dc equipment in China, caused by high altitude and heavy pollution, this paper presents the pollution flashover performance of full-scale ?800 kV converter station post insulators at actual high altitude area. The tests were carried out according to the solid layer method, and the 50% withstand voltage (U50%) was determined by the up-and-down method. The artificial contamination test results indicated that the shed configuration and the rod diameter had a significant influence on the flashover voltages. Shed parameters of one big and one small alternating shed composite post insulator which had superior dc pollution flashover performance had been recommended. The relationship between U50% and insulation height was approximately linear at actual high altitude area for post insulators. It was found that partial discharges occurred at the top section firstly and partial arcs easily appeared at the parts nearby the connecting fittings during the flashover process. And arc floating phenomenon was significantly serious in actual high altitude area. Furthermore, comparison was made between the U50% values of composite post insulators in fog and in rain. The U50% values in fog of composite post insulators were generally higher than that in rain. Thus, the outdoor insulation design of composite post insulators should primarily consider the U50% value in fog. This work thus provides useful reference for the design, operation and maintenance of UHV dc converter stations outdoor insulators in China. [ABSTRACT FROM PUBLISHER]