Size Optimizations to the Stress Cones in 48kV XLPE Cable Terminations

Abstract

It was described the size optimizations to the stress cones as which were key structre parts in the 27.5/48 kV XLPE cable heat/cold shrinkable combinated terminations, aslo included the effection performance to the elctric field strength by adjusted the radius to the innnerside bend surface of the stress cones. The result were indicated that the optimization could be applied for the designing and checking for the stress cones. I INTRODUCTIONAs a key components of the power cable heat and cold shrinkable combinated terminations, the cold-shrinkable silicone rubber stress cone parts were manufactured by silicone rubbers composite of two electrical properties. The conductive-type stress cones were made of conductive silicone rubbers by pressure molding in the first, and second step were that the insulated silicone rubber should be filled into the conductive silicone rubber stress cone embedded in the port, so a complete stress cone parts were constituted with conductive / insulating composite rubbers [1]. The conductive stress cones could play important role on evacuation of the electric field stress, and good or bad of its evacuation effected the product lifes of the XLPE cable terminations. Therefore, the size optimizations of the stress cone were key sequence for design and improvement of the cable accessories product, also as were a hot area of researches on the cable accessary theory.The companies in China began to develop and produce heat shrinkable cable accessories from the late 80's last centry, and some domestic researchers began to do the works on the numerical simulation of the electric fields in the cable terminations from medium 90's last centry, but most of these research works were focosted to the electric field stress intensity distribution which were effected by the parameters of the stress control tubes in the heat-shrinkable terminations[2-3].After the year 2000, cold shrinkable cable accessories and high-voltage cable accessories were manufactured and appllied with a large quantities, so many research workers were gradually increasing. In recent years, the cable accessaries research literature focused on the electric field numerical simulation of the cable terminations, which involved the establishment of the electric field model, finite element analysis and numerical calculations of the electric fields, and many innovative works [4][5][6][7][8]. These works were summarized in three points: the first, the object of the studies were aied to 110kV or higher voltage levels, the low voltage levels was limited for 10kV, 35kV and 48kV involved, which was relatively few, mainly because of the correlation between high voltage electric field models and objective dimensions of the stress cones were closely related to, the electric field structure was relatively simple and the significance of the studies with higher voltage was important more than the low-grade; the second was that almost research works were always followed the basic theory of the electric flux conservation(EFC) for electromagnetic fields[...

Electric Intensity Distribution of Cross-Linked Polyethylene Based High-Voltage Cable Termination

“…Improving the design of cable terminal plays an important role in improving the overall properties of cable [2]. The electric field distribution in the terminal can be controlled by optimizing the size of the stress cone [3] and using the stress control tube [4]. It is found that the selection of reinforced insulating materials in cable terminal will directly affect the distribution of field strength in terminals [5].…”