1.In order to reduce skin effect and improve transmission capability, the large section-area split conductor is elected.2.The VCV line is adopted to make extruded cores put into the culcanizing tube vertically. In order to settle insulation eccentric problem completely,the cores must be inspected by the insulation eccentric inspection appa ratus from Sikora in our company, and the line is all dry curing and tooting method.3.Triple-extruded technology, improved the electrical properties of cable highly, has be introduced in insulation, shield in and outside to make sure of smooth and compacted-connection border between those layers.4.To meet the requirements of longitudinal and radical water-proof and short circuit capability, expansive water-proof merial, corrugated aluminium and lead sheath is introduced. Its mechnical and water-proof properties are very well.5.In order to enssure the high purification of rare material strictly, extra- purification extra smooth imported materials as well as 1000-class purification room and all-tight input system are adopted in insulation and shield in and outside.6.Computer is adopted in VCV to select and control technical parameter to make sure of high control precision and automatic control degree.