Electrical connection structure for superconducting element

Abstract

The invention discloses an electrical connection structure for a superconductor element (30), which is cooled by a cryogenic fluid (31) and connected to an electrical bushing (10), which is passed continuously through a fluid between ambient temperature and cryogenic fluid The casing (12) at intermediate temperature and the casing (15) at ambient temperature, said bushing (10) protruding outside the ambient temperature casing. According to the invention, said intermediate housing (12) is at least partially filled with a solid material of low thermal conductivity, such as polyurethane foam or porous glass foam. The invention is applicable to connecting low temperature superconductor cables to devices deployed at ambient temperature.

Description

technical field [0001] The invention relates to an electrical connection structure for superconducting elements, such as cables for transmitting electricity at medium or high voltages. This configuration enables the end of the superconductor element at low temperature to be connected to a device or device, typically outdoors, at ambient temperature. Background technique [0002] Due to the large temperature difference between the superconductor element and the equipment to be connected to said element, i.e. between ambient temperature and low temperatures, possibly around -200°C, it is necessary to interpose connection structures between the element and the equipment, Grading the temperature while minimizing heat loss while still respecting electrical constraints eg due to cable high voltages. The structure includes an electrical bushing made primarily of a central conductor surrounded by an insulating sheath for delivering electricity from the superconductor cable to an ou...

AI Technical Summary

Problems solved by technology

It is therefore critical to ensure that the bottom and top walls where the electrical bushing passes are hermetically sealed, thus resulting in difficult and expensive manufacturing constraints

For example, even small leaks (e.g., about 10 -8 Millibar (mbar / L s) leakage) will inevitably lead to a change in the gas composition or a drop in the vacuum level in the intermediate housing

If the cryogenic liquid is liquid nitrogen, then the leak will lead to the presence of gaseous nitrogen in the intermediate enclosure, thus leading firstly to an additional consumption of liquid nitrogen and secondly to a reduction in the thermal insulation of the intermediate enclosure

Excessive pressure in the intermediate housing caused by such leaks cannot be controlled by means of a safety valve, since opening the safety valve would destroy the thermal insulating medium (vacuum or gas)

In addition, it is not easy to carry out on-site maintenance of the connection structure without leaving the workshop

For example, rebuilding the vacuum or refilling the gas in the intermediate housing while on site requires specialized equipment and specially trained personnel

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