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Description
The powering of the High Luminosity LHC (HL-LHC) magnets will rely on eight Cold Powering Systems incorporating Superconducting Links (SC Links) based on MgB2 cables. These cables are housed in compact and flexible vacuum-insulated pipes and transfer, via multiple cable configurations feeding circuits rated at currents ranging from 0.6 to 18 kA, total DC currents of about 120 kA at up to 25 K. The length of the SC Links reaches 120 m. Cryogenic cooling is with helium gas generated inside the systems. Two cryostats, located at each extremity of the SC Links, are part of each Cold Powering Systems. They provide, at one side, the connection at 4.5 K to Nb-Ti bus bar going to the magnets and, at the other side, a transition via REBCO cables to the resistive part of the current leads. The REBCO cables operate at up to 50 K. A Cold Powering System comprises up to nineteen HTS current leads, which are cooled by forced flow of helium gas transferred by the SC Link. The current leads are arranged in a compact configuration.
Following a development phase, which enabled qualification of individual system components, a first full-scale Cold Powering System has been constructed and tested at CERN. It contains all instrumentation needed for cryogenic operation and for protection of the superconducting circuits. To reproduce the configuration in the LHC underground, the system features a vertical path of about 5 meters. After a number of convolutions on the ground, the SC Link rises upward, supported by a cable chain, before being lowered, in a vertical configuration, inside the cryostat that contains the Nb-Ti bus-bar.
This paper reports on the results of the tests performed on the first HL-LHC Cold Powering System operated in nominal conditions and under various transient scenarios.
| Submitters Country | Switzerland |
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