Modeling of the Voltage Waves in the LHC Main Dipole Circuits

Ravaioli, Emmanuele; Dahlerup-Petersen, K.; Formenti, F.; Steckert, Jens; Thiesen, H.; Verweij, Arjan

doi:10.1109/tasc.2011.2176306

Cited by 13 publications

(26 citation statements)

References 8 publications

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“…5. The electrical perturbations introduced across the magnets of the chain have a maximum peak of a few hundred millivolt, significantly lower than the transients caused by switching-off the power converter or opening an energy-extraction switch [1], [2]. The voltage differences between apertures are also small as compared to the quench detection threshold of 100 mV.…”

Section: Simulation Of a Cliq In The Chain Of Lhc Dipole Magnetsmentioning

confidence: 99%

“…In the considered case, the voltage across the quenched magnet is comprised between -20 V and 6 V, corresponding to the diode opening voltages indicated in section III-C, and therefore the peak amplitude of a wave generated across a magnet is 26 V. This value is significantly lower than the initial voltage across the power converter of up to 165 V, or across an extraction switch, up to 800 V [1], [2]. Thus, the perturbations generated after a CLIQ discharge are about one order of magnitude smaller than those after the power converter switching-off and the switch openings.…”

Section: Simulation Of a Cliq In The Chain Of Lhc Dipole Magnetsmentioning

confidence: 99%

“…The equivalent lumped-element circuit proposed in [2], [3], [44] is used to model the behavior of an LHC dipole magnet at different frequencies. After validation under various operating conditions, it is now adopted as the standard tool for the simulation of electro-dynamic transients occurring in the eight LHC dipole magnet chains [2], [3].…”

Section: B Electro-dynamic Model Of An Lhc Main Dipole Magnetmentioning

confidence: 99%

“…After validation under various operating conditions, it is now adopted as the standard tool for the simulation of electro-dynamic transients occurring in the eight LHC dipole magnet chains [2], [3].…”

Section: B Electro-dynamic Model Of An Lhc Main Dipole Magnetmentioning

confidence: 99%

“…Simulated currents in the magnet circuit I chain , in the two coil sections I A and I B , through one CLIQ unit I C1 , and in the by-pass diodes I Dp and I Dap , versus time, after triggering a 2-CLIQ, 60 mF, 600 V system [4]. equivalent lumped-element network of one magnet, developed with the method described in [13], with the transmission line model presented in [2]. The interaction between the voltage transient developed after triggering CLIQ and the voltage waves generated at the output of the power supply and across the energy-extraction units is studied under various operating conditions.…”

Section: Simulation Of a Cliq In The Chain Of Lhc Dipole Magnetsmentioning

confidence: 99%

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CLIQ-Based Quench Protection of a Chain of High-Field Superconducting Magnets

Ravaioli

Datskov

Kirby

et al. 2016

IEEE Trans. Appl. Supercond.

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Abstract-Conventional quench protection systems for high magnetic-field superconducting magnets are based on external heaters composed of resistive strips in close contact with the coil, and rely on thermal diffusion across insulation layers of the order of tens of micrometer. The large contact areas between the coil and the heater strips, and the thin insulation between them required for an effective protection constitute a significant risk of electrical breakdown and one of the most common causes of magnet damage. CLIQ technology offers a valid option for a time-and cost-effective repair of magnets with failing heater-based protection systems. In fact, its effective heating mechanism utilizing coupling loss, its robust electrical design, and its fast implementation, as compared to alternative repair options, constitute definite advantages over the conventional technology. In the past years, CLIQ was successfully implemented on various coils in a single-magnet configuration. Now the design of a CLIQ-based protection system integrated in a chain of series-connected magnets is presented. The protection of a chain of superconducting magnets usually is considerably more challenging than the protection of stand-alone magnets due to the increased energy stored in the circuit and the presence of transitory effects. The effectiveness of this new method is demonstrated by means of electro-thermal simulations modeling the transition to the normal state and the temperature evolution in one quenched magnet, and the electrodynamics of the entire magnet chain.

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Section: Simulation Of a Cliq In The Chain Of Lhc Dipole Magnetsmentioning

confidence: 99%

Section: Simulation Of a Cliq In The Chain Of Lhc Dipole Magnetsmentioning

confidence: 99%

Section: B Electro-dynamic Model Of An Lhc Main Dipole Magnetmentioning

confidence: 99%

Section: B Electro-dynamic Model Of An Lhc Main Dipole Magnetmentioning

confidence: 99%

Section: Simulation Of a Cliq In The Chain Of Lhc Dipole Magnetsmentioning

confidence: 99%

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CLIQ-Based Quench Protection of a Chain of High-Field Superconducting Magnets

Ravaioli

Datskov

Kirby

et al. 2016

IEEE Trans. Appl. Supercond.

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The High Luminosity LHC interaction region magnets towards series production

Todesco

Bajas

Bajko

et al. 2021

Supercond. Sci. Technol.

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The High Luminosity Large Hadron Collider (HL-LHC) is the new flagship project of CERN. First endorsed in 2013 and approved in 2016, HL-LHC is an upgrade of the accelerator aiming to increase by a factor of ten the statistics of the LHC collisions at the horizon of 2035-2040. HL-LHC relies on cutting edge technologies: among them, large aperture superconducting magnets will replace the present hardware to allow a smaller beam size in two interaction points (IPs). The project involves the construction of about 150 magnets of six different types: the quadrupole triplet, two main dipoles and three orbit correctors. The triplet, manufactured at CERN and in the USA, will consist of 30 magnets based on Nb 3 Sn technology, with an Original content from this work may be used under the terms of the Creative Commons Attribution 4.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.

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Physics-driven lumped-element modelling for impedance simulations of superconducting accelerator magnets

Janitschke,

Bednarek,

Ravaioli

et al. 2024

Supercond. Sci. Technol.

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Superconducting magnets in particle accelerators are subject to various forces, radiation, high voltages, or thermal gradients. These can cause failures such as inter-turn shorts, which can be very challenging to detect after the magnets are installed in the machine. Measurements in the time- and frequency domain can pinpoint outlier magnets or precursors of such failures in the data. Interpretable, physics-driven simulations can facilitate this by explaining if manufacturing tolerances cause the observed behaviour or if it can be correctly classified as an outlier. An equivalent circuit model is proposed to simulate superconducting accelerator magnets’ impedances. The physics-driven model includes various coupled, non-linear effects in the superconductors, such as superconducting filament magnetisation, inter-filament and inter-strand coupling currents, eddy currents in the strands’ copper and various magnet components, and stray capacitances. The model is validatedagainst a wide range of available time- and frequency-domain measurements. A very good agreement is achieved across the different measurements and domains. The network model is computationally very inexpensive while still preserving good accuracy and interpretability. The model can hence be used to reproduce impedances of superconducting magnets accurately for performance evaluations and to investigate the impact of failures.

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Modeling of the Voltage Waves in the LHC Main Dipole Circuits

Cited by 13 publications

References 8 publications

CLIQ-Based Quench Protection of a Chain of High-Field Superconducting Magnets

CLIQ-Based Quench Protection of a Chain of High-Field Superconducting Magnets

The High Luminosity LHC interaction region magnets towards series production

Physics-driven lumped-element modelling for impedance simulations of superconducting accelerator magnets

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