Study In The Stress-Cone Of HTS Cable Terminals

Taking high temperature superconductors (HTS) as the conductors have many advantages such as small size, light weight, low loss, without a fire hazard and so on. Termination is one of the most important parts in the superconductor cable system. Especially the distribution of electric field at the end of the cable, the heat leakage of the current leads and the structure of the termination cryostat are the key technique for optimizing the termination design.This paper introduces the design of a220kV/3kA superconductor termination. The important parameter of stress cone will be given here by theoretical calculation. The electrical field in the stress-cone of power cable terminal is analyzed by finite element method (FEM). Stimulated results are realized by adjusting the length and curvature of the stress cone of this termination, respectively. Compared with the conventional method, the method can accurately calculate the terminal electric field distribution and optimize the design of the stress cone.This paper describes the characteristics of stress cone of HTS cables with different structures and analyses different electrical properties of common semiconductor materials in room temperature and low temperature environment. By the pressure test, lightning breakdown test and other job, the electrical properties of semiconductors in low temperature are researched deeply, and then t he electrical parameters of materials in room temperature and low temperature environment be gotton. The finally design scheme is that using Polypropylene laminated paper (PPLP) as the insulation material for main insulation layers and carbon paper as semiconductor materials for stress cone in HTS cable. After a miniature version of stress cone of HTS cables with35kV is constructed which replace bellows with stainless steel tube, high pressure test is performed. It is found the gap between application in practical engineering and simulation design. The paper analyzes the defective stress cone to seek improving methods and find relevant problems that will impact the design. It aims to have a better design by experiments. The results show that the new model accords with the expecting demand better and may provide an important reference to make an actual HTS cable.