熱収縮遮水層を用いた22kVCVTケーブル用接続部の開発

抄録

An expansionn of the applications for 22kV equipment and facilities in underground power-distribution systems is expected in the near future when taking into consideration controls and restrictions on the construction of new transformer substations for power distribution and the effective use of existing conduit lines. Moreover, the possibility has arisen for reducing overall costs while maintaining reliability of present-day 22kV XLPE cables and their joints based on the establishment of the Standard of the Japanese Electrotechnical Committee (JEC) 3408, “High voltage tests on cross-linked polyethylene insulated cables and their accessories for rated voltages from 11 kV up to 275 kV”.
This time, as part of the effort to reduce the material costs associated with 22kV systems, we will report on the developments of water-impervious straight joints and water-impervious Y-branch joints that correspond with developments of 22kV XLPE cables that have reduced insulation thickness to 3.5 millimeters with the introduction of a water-impervious aluminum layer. For water-impervious straight joints, a cold-shrinkable method (factory expansion) that provides excellent workability for assembly has been developed, and for water-impervious Y-branch joints, an insertion method that allows both removal and reconnection has been developed. In addition, these joints have been outfitted with a water-impervious construction by incorporating water-impervious shrinkable tubes comprising of an aluminum sheet in a similar fashion to water-impervious cables.