Cooling of Contact Connections of Current Leads of HTS Cables

Abstract

Efficient operation of terminal devices containing cryogenic current leads connecting the sources of power generation and consumption with a cable based on high-temperature superconductors ensures reliable operation of the entire power supply system. A method for calculating the temperature at the junction of a superconductor with the resistive part of a current lead when the current changes in the case of cooling the contact section with single-phase liquid nitrogen or gaseous helium is proposed. An analysis of heat removal from the contact area under conditions of free and forced convection has been performed, and the ratios between the heat transfer coefficients of liquid nitrogen and gaseous helium in the range of temperature and pressure values corresponding to the operating parameters of existing HTS cables have been determined. It is shown that the main influence on the thermal balance of the resistive and contact sections of the current lead is exerted by the temperature, and not by the heat transfer coefficient of the cryoagent used.