| Paper |
Title |
Page |
| WEPD007 |
Detection and Location of Electrical Insulation Faults on the LHC Superconducting Circuits during the Hardware Commissioning
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2413 |
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- D. Bozzini, V. Chareyre, K. H. Mess, S. Russenschuck
CERN, Geneva
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As part of the electrical quality assurance program, all superconducting circuits of the LHC have to be subjected to a (high) DC voltage, up to 1.9 kV DC, for the testing of the electrical insulation. Circuits with an insulation fault have to be repaired before powering. Fault location within a ± 3 m range over the total length of 2700 m has been achieved in order to limit the number of interconnection openings. In this paper, the methods, tooling, and procedures for the detection and location of electrical faults will be presented in view of the practical experience gained in the LHC tunnel. Three cases of faults detected and localized during the hardware commissioning phases of the LHC will be discussed.
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| WEPD008 |
Automatic System for the DC High Voltage Qualification of the Superconducting Electrical Circuits of the LHC Machine
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2416 |
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- D. Bozzini, V. Chareyre, S. Russenschuck
CERN, Geneva
- M. Bednarek, P. Jurkiewicz, A. Kotarba, J. Ludwin, S. Olek
HNINP, Kraków
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A system has been developed to verify automatically with the application of a DC high voltage, the insulation resistance between circuits to circuit and circuit to ground. In the most complex case of the LHC machine up to 72 circuits share the same volume inside the cryogenic lines and each circuit can have an insulation fault versus any other circuit or versus ground. The system can connect up to 80 circuits and apply a voltage up to 2 kV DC. The leakage of current flowing through each circuit is measured within a range of 1 nA to 2 mA. The matrix of measurements characterizes the paths taken by the currents and recognizes weak points of the insulation between circuits. The system is composed of a DC voltage source, a data acquisition card that measures with precision currents and voltages and drives up to 5 high voltage switching modules offering each 16 channels. A LabVIEW based application controls the system for an automatic and safe operation. This paper describes the hardware and software design, the testing methodology and the results obtained during the qualification of the LHC superconducting circuits.
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| WEPD016 |
Electrical Quality Assurance of the Superconducting Circuits during LHC Machine Assembly
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2440 |
| |
- S. Russenschuck, D. Bozzini, V. Chareyre, O. Desebe, K. H. Mess
CERN, Geneva
- M. Bednarek, D. P. Dworak, E. Gornicki, P. Jurkiewicz, P. J. Kapusta, A. Kotarba, J. Ludwin, S. Olek, M. Talach, M. Zieblinski
HNINP, Kraków
- M. Klisch, B. Prochal
AGH, Cracow
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Based on the LHC powering reference database, all-together 1712 superconducting circuits have been electrically wired and interconnected in the various cryogenic lines of the LHC machine. Continuity, magnet polarity, and the quality of the electrical insulation have been the main objectives of the Electrical Quality Assurance (ELQA) activities during the LHC machine assembly. Another activity aimed at ensuring the coherence between the reference database on one side, and the polarity conventions used for beam simulation and magnetic measurements. With the assembly of the LHC now completed, the paper reviews the methods and procedures established for the ELQA, as well as the employed time and resources. The qualification results will be presented with the emphasis on the detected electrical non-conformities and their possible impact on the performance of the LHC machine.
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