Quench Recovery Research Articles

Study on Reduction of Quench Recovery Time by Inductive Energy Extraction

Study on Reduction of Quench Recovery Time by Inductive Energy Extraction

Numerical Study on Thermal Stability of No-Insulation Coils Using a Three-Dimensional Finite-Element Model

No-insulation (NI) coils possessing maximized volume current and quench recovery ability have become one of the most promising technologies for high-field high-temperature superconducting windings. In this article, we constructed a complete 3-D finite element model incorporated with the circuit and heat modules that allows a detailed simulation on the transportation behaviors of the NI coils. Critical problems including the circulating and radial electro-magnetic transportation behaviors during the excitation process with different ramping rates; the thermal propagation in the overcurrent circumstance and related quench protection; and the effect of parallel winding of stainless steel tapes have been investigated using the newly proposed model. A detailed comparison of NI and metal-insulated coils on thermal stability and quench recovery ability with the presence of hot spots has been implemented. Such a 3-D model enables a close look at the electrical and magnetic field distribution, and predicts more accurate coil-parameters for the circuit model where detailed material properties can as well be included.

Thermohydraulic simulation of quenches and quench recovery for the HL-LHC IT String test bench at CERN

In the framework of the High Luminosity LHC (HL-LHC) project, a new test system - the Inner Triplet (IT) magnets String - for the characterization and validation of the collective behaviour of a 60 m long string of magnets is being built in the SM18 cryogenic test facility at CERN. Among the main objectives of the IT String is the assessment of the magnet performance during the resistive transition from the superconducting to the normal state (quench) when energies up to 39.1 MJ are released into the magnet cold mass and into the helium. In this paper we present the thermohydraulic study performed to design the quench recovery system of the IT String, which limits the pressure rise in the magnets during a quench and ensures the recovery of the operating conditions within the required timeframe. As a new design method, a 1-D thermohydraulic model of the quench relief system has been created using the EcosimPro software with the CRYOLIB library developed at CERN.

Comparative Study of Superconducting DC Energy Pipelines With Different Bipolar Structural Layouts

Superconducting DC energy pipeline combines long-distance electricity and liquified natural gas transmission, which could improve the overall efficiency of the pipeline system and save construction space. The characteristics of superconducting DC energy pipelines with bipolar coaxial, double-core and partitioned structural layouts are analyzed and compared in this paper, which are significant for the selection of pipeline structure. The voltage levels are set as ±10 kV/±100 kV for electricity distribution and transmission applications, and the rated current is set as 1 kA. The simulation models of energy pipelines with each structural layout are established in order to evaluate the respective operation characteristics. The operation conditions of the steady state, the quench transient process under a short-circuited fault and the quench recovery transient process afterwards are analyzed in order to evaluate the stability and safety of the pipeline system. The comparison results illustrate the distinguishing features of each structural layout from various aspects. It is found that the double-core structure and the partitioned structure are the most suitable options at the voltage levels of ±10 kV and ±100 kV respectively.

Quench recovery time of an optical fiber encapsulated resistance-type DC superconducting fault current limiter coil determined by a Raman-based distributed temperature sensing system

The superconducting fault current limiter (SFCL), as a very important power facility for high voltage DC system, can consume fault current energy and make DC breakers cut off fault transmission lines successfully. For the moment of reclosing DC breakers, the quench recovery time of the SFCL must be determined in advance. In this article, according to the design requirement of a 160 kV/1 kA resistance type DC SFCL in the Nan’ao multi-terminal flexible HVDC transmission demonstration project, the quench recovery time of a SCFL coil wound by two optical fiber encapsulated high temperature superconducting (OFE-HTS) tapes was checked by our optimized Raman-based distributed temperature sensing (Rm-DTS) system. The experimental results show that the used OFE-HTS tapes can withstand a 1500 A/100 ms AC short circuit current impact and are qualified with the SFCL. Furthermore, the quench recovery time of the SFCL coil measured by the Rm-DTS was 2930 ms. During the quench, the highest temperature zone occurred near the center of the SFCL coil.

Femtosecond control of phonon dynamics near a magnetic order critical point

The spin-phonon interaction in spin density wave (SDW) systems often determines the free energy landscape that drives the evolution of the system. When a passing energy flux, such as photoexcitation, drives a crystalline system far from equilibrium, the resulting lattice displacement generates transient vibrational states. Manipulating intermediate vibrational states in the vicinity of the critical point, where the SDW order parameter changes dramatically, would then allow dynamical control over functional properties. Here we combine double photoexcitation with an X-ray free-electron laser (XFEL) probe to control and detect the lifetime and magnitude of the intermediate vibrational state near the critical point of the SDW in chromium. We apply Landau theory to identify the mechanism of control as a repeated partial quench and sub picosecond recovery of the SDW. Our results showcase the capabilities to influence and monitor quantum states by combining multiple optical photoexcitations with an XFEL probe. They open new avenues for manipulating and researching the behaviour of photoexcited states in charge and spin order systems near the critical point.

Investigations on Quench Recovery Characteristics of High-Temperature Superconducting Coated Conductors for Superconducting Fault Current Limiters

Superconducting fault current limiters (SFCLs) are attracting increasing attention due to their potential for use in modern smart grids or micro grids. Thanks to the unique non-linear properties of high-temperature-superconducting (HTS) tapes, an SFCL is invisible to the grid with faster response compared to traditional fault current limiters. The quench recovery characteristic of an HTS tape is fundamental for the design of an SFCL. In this work, the quench recovery time of an HTS tape was measured for fault currents of different magnitudes and durations. A global heat transfer model was developed to describe the quench recovery characteristic and compared with experiments to validate its effectiveness. Based on the model, the influence of tape properties on the quench recovery time was discussed, and a safe margin for the impact energy was proposed.

10 kV AC test verification of the high temperature superconducting fault current limiter with bias magnetic field

Under the support of the China State Grid Corporation Science and Technology Project, a set of 10 kV superconducting fault current limiter (SFCL) with bias magnetic field including a high temperature superconducting a low inductance unit, a double split reactor, a fast breaker and its control system is designed and assembled in Hushitai high voltage center of Electric Power Research Institute of State Grid Liaoning Electric Power Co., Ltd. The 10 kV dedicated test including high voltage test, phase to phase short circuiting fault test, quench resistance measurement, quench recovery time measurement were performed in December 2019. The fault current distribution and voltage test results during the phase to phase short-circuit fault of the SFCL are presented and analyzed. Test results indicate that current limiting resistance of SFCL unit is about 1.21 Ω within 10 ms fault time. Those results meet the design requirement.

Numerical Study of the Influence of the Encapsulation Layer on the DC Over-Current Performance of HTS Coated Conductors

© 2002-2011 IEEE. The application of resistive superconducting fault current limiters (R-SFCLs) in voltage source converter (VSC)-based DC systems has been proposed, and the encapsulated high temperature coated conductors (HTS-CCs) used for R-SFCLs is getting practical. Thus, this paper respectively develops a 1-D HTS-CC model and a 2-D HTS-CC model with different thicknesses to investigate the resistance characteristics and the quench recovery time. The results show that the resistance of encapsulated HTS-CCs goes through the flux flow state before reaching the normal. Then, the encapsulation can expand the limit of fault current, and a suitable thickness is likely to reduce the total resistance of the R-FCL. Finally, due to the existence of the heat transfer between the HTS-CC surface and the liquid nitrogen bath, a thinner tape might recover faster, and the recovery time tends to rise slowly as the tolerated current increases.

Design and Test of 40-kV/2-kA DC Superconducting Fault Current Limiter

In this article, a general scheme of a 40-kV/2-kA resistive type dc superconducting fault current limiter (SFCL) is suggested, which could be utilized to suppress the surge current caused by short-circuit faults in voltage-source-converter HVdc (VSC-HVdc) power grids. This dc SFCL is designed and fabricated with 6 coil modules in parallel and 4 in series. In order to investigate the current-limiting performance of the dc SFCL under the rapidly rising fault current, the SFCL is tested on the platform with a pulsed dc impact generator. Besides the property of current limitation, the current capacity, insulation and quench recovery performance of such SFCL are also tested. Results indicate that the critical current of SFCL is larger than 2050 A at 69 K, and the dc withstand voltage is larger than 74 kV in 2 h. During the 9-kV dc impact test, the short-circuit current could be limited to 8842 A, and the quench recovery time is less than 200 ms.

First operational experience of the upgraded cryogenic infrastructure of the vertical magnet test facility in the SM18 hall, including HFM and cluster D test stations.

As part of the R&D program for HL-LHC, the future upgrade of the Large Hadron Collider (LHC), the vertical magnet test facility in the SM18 cryogenic test hall at CERN has seen significant development. Since the installation of HFM and Cluster D cryogenic test stations in 2017, the facility is comprised of five vertical test cryostats of various sizes operating at either 1.9 K or 4.2 K. It is now possible to test a wide range of superconducting high field magnets with weigh up to 18 tons, maximum stored energy of 10 MJ and powering requirements up to 30 kA. This article describes the first cryogenic operational experiences with these test stations, their cool-down and warm-up characteristics and the heat in-leak measurements of their components. Major upgrades made to the cryogenic infrastructure of the vertical magnet test facility as a whole are also detailed. This includes the adoption of an improved safety strategy to ensure the continued safe operation of the test facility during all operational modes. As well as the incorporation of quench recovery systems on four of the five test stations to reduce the amount of helium lost during testing and the installation helium guards on infrastructure operating at 1.9 K to avoid the ingress of air to cryogenic circuits.

State Machine Operation of the MICE Cooling Channel

The Muon Ionization Cooling Experiment (MICE) is a demonstration experiment to prove the feasibility of cooling a beam of muons for use in a Neutrino Factory and/or Muon Collider. The MICE cooling channel is a section of a modified Study II cooling channel which will provide a 10% reduction in beam emittance. In order to ensure a reliable measurement, MICE will measure the beam emittance before and after the cooling channel at the level of 1%, a relative measurement of 0.001. This renders MICE a precision experiment which requires strict controls and monitoring of all experimental parameters in order to control systematic errors. The MICE Controls and Monitoring system is based on EPICS and integrates with the DAQ, Data monitoring systems, and a configuration database. The cooling channel for MICE has between 12 and 18 superconductnig solenoid coils in 3 to 7 magnets, depending on the staged development of the experiment. The magnets are coaxial and in close proximity which requires coordinated operation of the magnets when ramping, responding to quench conditions, and quench recovery. To reliably manage the operation of the magnets, MICE is implementing state machines for each magnet and an over-arching state machine for the magnets integrated in the cooling channel. The state machine transitions and operating parameters are stored/restored to/from the configuration database and coupled with MICE Run Control. Proper implementation of the state machines will not only ensure safe operation of the magnets, but will help ensure reliable data quality. A description of MICE, details of the state machines, and lessons learned from use of the state machines in recent magnet training tests will be discussed.

An Effect of HTS Wire Configuration on Quench Recovery Time in a Resistive SFCL

We experimentally investigated the correlation between the high-temperature superconducting (HTS) wires configuration in an HTS element and recovery time after quench in a resistive superconducting fault current limiter. The variables of the configuration are horizontal and vertical gap distances between HTS tapes in an element. Eight samples were made with different gap distances and tested. A SUS-stabilized YBCO tape with 4.4 mm width had been used in the experiment. It was cooled by LN2 in a cryostat under the pressure of 1 bar, saturated state. In the short-circuit test, the temperature of the wire's surface was measured. Recovery time of the HTS sample increased with decreasing horizontal and vertical gap distance due to stagnation of bubbles. When the gap distance was larger than a size of a bubble, the effect of gap distance was ignorable. Considering a volume and recovery time, the sample that has narrower gap distance was favorable.

Considerations for Designing a Conduction-Cooled Sample Holder

Usually, superconductive strands are characterized and quality controlled by performing short sample tests. These tests are often carried out using liquid cryogen or cold gas flow as coolant. However, in some measurements, the use of a more adiabatic approach is beneficial. This can be achieved with a conduction-cooled system. The advantages and the disadvantages of using a conduction-cooled measurement are presented. The thermal and electrical aspects of a typical conduction-cooled sample holder are discussed by studying the steady-state and transient operation of such a setup with a 3-D finite-element method model. Also, improving the electrical contact resistance of a clamped current/cooling contact facilitating fast sample changeover was experimentally analyzed. The obtained results indicated that an inadequate sample holder can cause excessive heat generation, can slow down quench recovery, and can complicate burnout protection. Finally, the electrical and thermal properties of typical MgB <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> samples under test were modeled to have a significant effect on the operation of a conduction-cooled measurement system. An order of magnitude increase was observed in both ohmic losses and quench recovery time, when the outer sheath material of the simulated superconductor was changed from copper to Monel.

A Cation-regulated and Proton Gradient-dependent Cation Transporter from Chlamydomonas reinhardtii Has a Role in Calcium and Sodium Homeostasis

The CrCAX1 gene encoding a Ca2+/H+ and Na+/H+ exchanger was cloned and characterized from the unicellular green alga Chlamydomonas reinhardtii to begin to understand the mechanisms of cation homeostasis in this model organism. CrCAX1 was more closely related to fungal cation exchanger (CAX) genes than those from higher plants but has structural characteristics similar to plant Ca2+/H+ exchangers including a long N-terminal tail. When CrCAX1-GFP was expressed in Saccharomyces cerevisiae, it localized at the vacuole. CrCAX1 could suppress the Ca2+-hypersensitive phenotype of a yeast mutant and mediated proton gradient-dependent Ca2+/H+ exchange activity in vacuolar membrane vesicles. Ca2+ transport activity was increased following N-terminal truncation of CrCAX1, suggesting the existence of an N-terminal auto-regulatory mechanism. CrCAX1 could also provide tolerance to Na+ stress when expressed in yeast or Arabidopsis thaliana because of Na+/H+ exchange activity. This Na+/H+ exchange activity was not regulated by the N terminus of the CrCAX1 protein. A subtle tolerance by CrCAX1 in yeast to Co2+ stress was also observed. CrCAX1 was transcriptionally regulated in Chlamydomonas cells grown in elevated Ca2+ or Na+. This study has thus uncovered a novel eukaryotic proton-coupled transporter, CrCAX1, that can transport both monovalent and divalent cations and that appears to play a role in cellular cation homeostasis by the transport of Ca2+ and Na+ into the vacuole.

First Cool-Down and Test at 4.5 K of the ATLAS Superconducting Barrel Toroid Assembled in the LHC Experimental Cavern

The large ATLAS superconducting magnets system consists of the Barrel, two End-Caps Toroids and the Central Solenoid. The eight separate coils making the Barrel Toroid (BT) have been individually tested with success in a dedicated surface test facility in 2004 and 2005 and afterwards assembled in the underground cavern of the ATLAS experiment. In order to fulfill all the cryogenic scenarios foreseen for these magnets with a cold mass of 370 tons, two separate helium refrigerators and a complex helium distribution system have been used. This paper describes the results of the first cool-down, steady-state operation at 4.5 K and quench recovery of the BT in its final configuration.

Simulation of electromagnetic and thermal processes in Rutherford superconducting cables during the initiation of a quench

Thermal stability for superconducting fast-cycling dipoles will play a vital role. The coupled numerical simulation of electromagnetic and thermal processes in Rutherford superconducting cables during the initiation of a quench was carried out. The network model has been combined with thermal analysis, which allows one to model quench dynamics, including the effects of current redistribution in strands, discontinuities and inhomogeneity, the initial heating in strand, and as results occasional quench recovery or runaway quench propagations.

Investigation on the stability evaluation of multi-strand superconducting cable related with ramp-rate limitation

This paper describes stability of CICC superconducting magnets related with RRL (Ramp-Rate Limitations). Although RRL is known as a significant obstacle for successful operation of field-varying AC superconducting magnets, its precise investigation is difficult due to complex unknown parameters and difficulties of experimental measurements. To investigate RRL for practical multi-strand CICC, a simplified analysis model is suggested with some reasonable assumptions. This model considers accurate current diffusion phenomenon inside CICC and realistic transient convection heat transfer by supercritical helium. Parametric study is also performed with the analysis model to investigate the effect of the strand parameters. Summarizing the quench recovery or cable quench result after a local quench for given simulation parameters, a new stability evaluation method is suggested and it can give some design criterion by guaranteeing the stable operation regime of superconducting magnets. The new evaluation method, which is called ‘RRL quench recovery map’, is applied to the previous experimental results and it shows that this map can be used as a design criterion for practical superconducting magnets.

Short-Circuit Characteristics of Non-Inductively Wound Solenoid Magnet With Various Insulating Materials

To select electrical insulator (insulator) between coated conductor tapes (CC tapes) of two parallel non-inductively wound solenoid type superconducting fault current limiter (SFCL) is a important issue. Insulator is inserted for separation of two parallel tapes. Quench characteristics and recovery time of SFCL are related on insulator and thermal contact condition. Insertion of tape-shape insulating materials is a normal way of insulation for non-inductively wound SFCL. Thus, various tape-shape insulating materials can be the insulator of SFCL. In this paper, sample holder to simulate parallel tapes with various insulators was fabricated, and sticky polyimide tape and insulating paper tape were chosen for insulator of samples. Short-circuit test was performed in the same condition except inserted insulator of samples. Quench characteristic, generation of resistance, and recovery time of each sample were compared to the others. Special sample holder was used to observe current division and sharing in two parallel coated conductor tapes. The variation of the voltage applied to the module for short-circuit test was from 1.82 (V) to 12.7 (V).

Investigation of Heat Transfer Effect on Ramp-Rate Limitation of Superconducting Cable

Ramp-rate limitation, which is known as a serious obstacle for fast charging of a superconducting magnet, is investigated by an experiment with a two-strand sample conductor and numerical analysis. During the experiment, typical ramp-rate limitation results were observed. The sample showed quench recovery by current redistribution or irreversible 'cable quench' according to the operation conditions. To investigate the recovery or quench criterion, numerical analysis is performed considering both electro-magnetic and thermal interaction. The simulation results show that the status of the low-current strands determines 'recovery' or 'cable quench' when the 'local quench' first occurs at the high-current strand. From the analysis, heat transfer conditions such as boiling heat transfer and contact heat transfer between the strands as well as current nonuniformity are the most governing factors for the stability criterion. Therefore, it is possible to propose a stability criterion for the ramp-rate limitation according to the operation condition of the superconducting magnet. Moreover, the effect of heat transfer conditions to overcome the ramp-rate limitation for the given operation conditions is investigated quantitatively.