Conductor Layout Research Articles

Design and Feasibility Assessment of an HTS Sector Shaped High-Current Conductor for Fusion Coils

Technologies based on High Temperature Superconductors (HTS) are evolving rapidly toward maturity. Within the magnetic confinement fusion environment, several projects are demonstrating the possibility to integrate HTS in the coil systems. With respect to Low Temperature Superconducting (LTS) technologies, HTS could allow extending the operating space of fusion coils, either at higher temperatures, or at higher magnetic field levels, and in any case with larger operating margins. Different perspectives and development strategies are proposed, depending on whether HTS is considered a technology to completely substitute LTS, or to integrate and extend its performance range. A fundamental common requirement is the assessment of the layout, the feasibility, and performance demonstration of high-current conductors. Starting from the results achieved with the Al-slotted core cable-in-conduit conductor, and with a view on existing concepts for standard copper and aluminum cables, we have designed a new HTS sector-cable concept, to allow a flexible conductor design and a robust industrial processing. Several trials have been carried out, to verify the manufacturing approach, using either Al- or Cu-based stabilizers. Prototype sub-cables have been characterized at 77 K and self-field, as a necessary step toward the final target of a CICC operating stably with 60 kA at 4.2 K and 18 T, that is presently of interest for the EU-DEMO Central Solenoid Coil.

Instalasi Ulang Penerangan Listrik di Pondok Pesantren Tarbiyatunnisa Desa Serdang Kulon Kecamatan Panongan Kabupaten Tangerang

In today's human life, presumably almost depend on electricity. Some of the things that arise if there is a disturbance in electricity, among others, there is no lighting resulting in darkness at night. Electrical installation installation standards have been regulated in the General Electrical Installation Requirements. Apart from matters relating to the security of the electrical installation network, there are other things that we must pay attention to. This is the standard intensity of illumination. The intensity of room lighting is determined in lux units. The amount of room lighting intensity has been regulated in SNI 03-6575-2001. If the lighting intensity in a room is inadequate, it will cause impaired vision problems. The purpose of this activity is to ensure that the lighting installation meets the standards for both installation safety and lighting intensity. The methods of these activities are lectures, counting and reinstalling lighting installations at the Islamic boarding school. is to calculate the amount of safety, conductor, component specifications, and component layout. In addition, the capacity and number of lamp requirements for each room are calculated. The re-installation is carried out by replacing all electrical networks using standard quality components and installing light points as needed. The conclusion of these activities is that after carrying out these activities the installation becomes safe and the lighting of each room is as needed

Optimum Design and Performance Analysis of Superconducting Cable with Different Conductor Layout

Compared with the traditional cable, the high-temperature superconducting (HTS) cable has the advantages of low loss and large capacity transmission. At present, the research on HTS cables mainly focuses on the calculation of AC loss, the performance under specific working conditions and cooling system design. Relatively little research has been carried out on the basic design and overall layout optimization of the cables. In this paper, an HTS cable with a rated current of 4 kA was designed. Firstly, according to the selected superconducting cable parameters, the body design of cables with different structures was carried out and the corresponding finite element models were built. Then, the performance analysis of HTS cables with different layouts was carried out based on the proposed cable performance evaluation indicators and the CORC double-layer structure was determined as the scheme of this cable. Finally, the AC loss of the cable with this topology was calculated to be 9.81 J/m under rated conditions. The cooling system can ensure the safe operation of the cable in the rated temperature range.

The Optimization Study for Electromagnetic Radiation With Ultrahigh Voltage Transmission Lines

Several factors affect the electromagnetic environment changes generated underneath high-voltage transmission lines. This article carries out a study on the impact of the electromagnetic environment on high-voltage transmission lines based on different tower structures, voltage levels, conductor layouts, conductor parameters, and other full range of engineering factors. First, the model of wire three-phase phase sequence, ground height, horizontal phase spacing, wire splitting number, split spacing, and model values are built. By continuously adjusting and optimizing the parameters, the electromagnetic environment distribution curve at 1.8 m above the horizontal plane is obtained. Then, according to the characteristic analysis of the distribution law after optimization, the simulation results under some typical factors are compared with the standard limits. Simultaneously, the effect of this optimization is verified by comparison with relevant literature. Finally, some suggestions on the optimization of the pole tower structure, transmission line parameters, and the influence of electromagnetic radiation in transmission line corridors are proposed in high-voltage transmission line projects, which may potentially have constructive contributions and value.

ВЛИЯНИЕ ТОПОЛОГИИ ОБЩЕГО ВЫВОДА НА АЧХ ИНТЕГРАЛЬНОГО СВЧ LC-ФИЛЬТРА

The paper describes the developed model of 18 GHz high-pass filter (HPF). The filter model includes models of inductors, MIM capacitors, and conductors allows for skin-effect, edge effects, substrate influence, and the influence of the substrate contacts layout. The developed model has been verified by experimental prototype of the filter, which is made in the standard process of 130 nm silicon-germanium (SiGe) BiCMOS. It has been found that the developed model has cutoff frequency, passband and stopband attenuations, and gain slope close to the experimental prototype. The recommendations of the microwave LC-filters ground conductor layout design are expressed based on developed model.

Optimization of a Close-Fitting Volume RF Coil for Brain Imaging at 6.5 mT Using Linear Programming.

The use of a close-fitting roughly head-shaped volume coil for MRI (magnetic resonance imaging) has the merit of improving the filling factor and thus the SNR (signal-to-noise ratio) from the brain. However, the surface of the RF coil follows that of the head which makes it difficult to determine an optimal coil winding pattern. We describe here a new method to optimize a head-shaped RF coil with the objective of maximizing its SNR and RF-magnetic-field homogeneity for operation at ultra-low magnetic field (6.5 mT, 276 kHz). The approach consists of FEM (finite-element-method) simulation and linear programing based optimization. We have implemented the optimization and further studied the relationship between the design requirements and the performance of the RF coil. Finally, we constructed an optimal RF coil and scanned both a head-shaped phantom and a human subject. The method we outline here provide new insight into the conductor layout needed for magnetic optimization of structurally complex coils, especially when tradeoffs between competing attributes (SNR and homogeneity in this case) must be made.

Magnetic Design of a Superconducting Toroidal Gantry for Hadron Therapy

Hadron and proton therapy are cutting edge techniques for cancer treatment and a great development of specialized medical centers and research facilities is foreseen in the next decades. One of the main obstacles to the penetration of the use of charged particles for therapy is the construction of complex and expensive accelerating structures and rotating transfer lines, i.e., gantries, able to bend and focus the beam down to the patient. GaToroid is a novel concept of a fixed toroidal gantry, able to deliver the dose at discrete angles in the whole range of treatment energies in steady-state configuration. The steady-state current and magnetic field are appealing features, implying simplified demands on stability, powering, mechanics and cooling, as well as for the clinical perspective, allowing rapid variations of beam energy and treatment angle. In this work, we present the magnetic design of the toroidal coils composing the first instance of GaToroid, focusing the analysis on an option for a proton machine with an energy range of 70 MeV to 250 MeV. To create a proper magnetic field distribution, the coils have been designed with peculiar asymmetric shape and the windings have been graded. An initial winding geometry was obtained with an optimization aiming at maximum energy acceptance of the gantry. We are now progressing to the detailed engineering design. We describe here the overall magnet design, coil and conductor layout (LTS and HTS options), and mechanical studies involving the general torus structure. Quench protection is evaluated for LTS (Nb-Ti) configuration, as well as more innovative HTS (ReBCO) options. Finally, we present the design and the construction of a scaled-down demonstrator, intended as the proof of principle of winding procedure and mechanical coil structure.

Current Center Line Integration in the Manufacturing Process of the ITER Toroidal Field Coils

The first ITER's European Toroidal Field Coil (TFC) is going to be assembled in 2019. The TFC is composed mainly by the superconducting Winding Pack (WP - manufactured in Europe), and the Coil Cases (TFCC - manufactured in Japan), which provide structural integrity to the magnet and offer interface connections with the rest of the machine. Dimensional measurements and other manufacturing data are taken during the WP manufacture and are used to reconstruct the Current Centre Line (CCL), which is defined as the barycentre of the as-built conductors inside the WP. The CCL is useful to characterize the magnetic field generated by the magnet, and its monitoring and control can minimize the Error Field during ITER operation. Fusion For Energy (F4E) developed a method to calculate the CCL using manufacturing data. Since the CCL represents how different the WP is manufactured from its nominal conductor layout, this deviation can be corrected where there is need of a more controlled magnetic field shape, namely in the straight inboard area of the D-shaped tokamak. That is why each WP position inside its respective TFCCs is optimized, compensating the deviations detected and maintaining an allowable gap between components for the subsequent welding and resin filling operation. This paper presents the strategy followed by F4E to calculate the CCL and optimize the WP position inside the TFCC, by means of extensive CAD and CAE modelling activity. It explains also the data management process developed and followed to ensure configuration control of all the data inputs and outputs, coming from different sources and formats, and details the successful insertion operation on the first ever ITER TFC coil manufactured in Europe, and how in the future the updated CCL coil position will be used to define the final TFC machining, after the welding and gap filling operations.

Analytical model for large deflection bending of helically stranded electrical wires

An analytical model is presented to calculate the elasto-plastic bending response of electrical wires subjected to large deflections. Electrical wires are defined as helically wound conductors enclosed in polymer insulation. For modeling purposes, the conductor layout in a wire’s cross section is estimated using a packing algorithm. Euler-Bernoulli beam theory describes the overall wire bending behavior; the conductors’ stick-slip behavior is modeled based on Coulomb’s friction law. In the plastic region, the conductors are modeled as laminated composite beams. A cantilever bending setup is used to characterize the force displacement response of wires with different diameters, number of conductors, beam lengths, and conductor cross sections. The model parameters are calibrated to ensure that the force-displacement calculations are within the 95% confidence interval of the test data.

Hall voltage measurement with respect to internal layout of REBCO coated conductors in an external magnetic field

Hall voltage measurement with respect to internal layout of REBCO coated conductors in an external magnetic field

Equivalent Thermal Conductivity Estimation for Compact Electromagnetic Windings

This paper presents a new estimation method for the equivalent thermal conductivities of the compact slot windings formed from round conductors. The estimation accuracy of thermal conductivities is essential for peak temperature prediction to avoid overheating failures in the high power density electromagnetic devices. The compact windings with orderly wound conductors perform better on heat dissipation and take smaller slot space than the random wound types. In recent years, the winding technology has made great improvement, and the compactness of conductors is significantly elevated. After observing the cross section of the windings, the randomness of the wire's layout is greatly reduced and a certain regularity is shown. The proposed estimation method takes the geometric characteristics of the internal structure into account to improve the estimation accuracy of the traditional methods, which use the proportion of each material only. Considering the layout of conductors is not completely regular, the impact of the dislocation between conductors is explored. Then, the conclusion is used to modify the analytical result. The experimental test result shows that the proposed theoretical method is easy to apply and meanwhile performs satisfactory in terms of high accuracy and low computation.

Quench Simulation of REBCO Cable-in-Conduit Conductor With Twisted Stacked-Tape Cable

Quench protection is a critical issue for magnet using high-temperature superconducting (HTS) materials such as REBCO. For cable-in-conduit conductor (CICC) with twisted REBCO tapes, which is considered for high-current HTS conductor for fusion magnet, the anisotropic critical current density (Jc) of tape and complex conductor layout will further complicate the quench behavior. The CryoSoft code THEA is used to simulate the quench behavior of various subscale CICCs in view of a quench experiment in SULTAN facility. The CICCs are composed of twisted tape stack assembled into copper shell (strand). It has been found that neglecting the anisotropy of Jc in quench simulation will significantly underestimate the hot spot temperature by about 40 K. Therefore, it could leave potential risk to damage the magnet. It is also shown that the thermal contact resistance between strand and the steel jacket (the conduit) plays a very important role on quench behavior. The hot spot temperature can be reduced by more than 100 K if the thermal resistance is reduced by two order of magnitude. On the other hand, variations of interstrand electrical and/or thermal resistance have only very little influence (few kelvin).

Development of Live Working Device Based on Zero Potential Control Principle

In the case of live working in the distribution network, serious safety accidents will occur due to weak operation and weak safety awareness. The live working methods and equipment that meet the requirements for personal safety and power supply reliability need to be studied. In order to improve the safety of live working in distribution network, the working point zero potential control principle is proposed, and a prototype of the zero potential live operation device for distribution network is developed based on this principle. The principle and design of the charged working equipment based on the principle of zero potential control are introduced. The prototype has the functions of data collection, data analysis, logic protection and information transmission. When the selection and layout of the line conductors are different, the line parameters will also be different. For different conductor selection and layout schemes, three schemes are designed to simulate separately. The system model is established based on MATLAB, and the feasibility of the proposed method is verified by the working phase voltage curve. Experiments and third-party inspections show that the device is reliable in operation, quick in response, easy to operate, and can meet the zero potential control requirements of live working, which is of great significance to improve the safety of live working in distribution network.

Effect of transverse compressive monotonic and cyclic loading on the performance of superconducting CORC® cables and wires

Superconducting CORC® cables and wires have become practical conductors for use in high-field magnets for fusion machines and particle accelerators by demonstrating their ability to carry very high currents in background magnetic fields of up to 20 T. The high mechanical stresses that develop on the CORC® conductor during such operation could result in permanent degradation of the conductor critical current. Transverse compressive stress is one of the predominant mechanical stresses when CORC® cables or wires are bundled into CICCs that allow fusion and detector magnets to operate at currents as high as 100 kA. The effect of transverse compressive load on the critical current of CORC® cables and wires has been investigated at 76 K to determine their irreversible load limit under monotonic loading and load cycling up to 100 000 cycles. The results show a clear effect of the CORC® conductor layout with respect to gap spacing between tapes, thickness of the copper plating surrounding the tapes and thickness of the former onto which the tapes are wound. CORC® cables and wires have demonstrated a remarkable resilience to transverse compressive load cycling where their critical current decreased by no more than a few percent after 100 000 load cycles at peak loads that resulted in an initial decrease in critical current of less than 5%. The results indicate that no significant degradation of CORC® cable and wire performance due to transverse compressive load is expected in large magnets after 100 000 load cycles, as long as the peak load on the conductor does not exceed the irreversible load limit defined at 95% retention in critical current. The irreversible load limit of CORC® conductors could be increased further by increasing the size or hardness of the former that makes up the conductor’s core.

New design of inter-layer splice joint for the TF coils of the DEMO- EUROfusion tokamak

Since the year 2013, the Swiss Plasma Center (SPC) has proposed a Toroidal Field (TF) layout for the DEMO- EUROfusion tokamak, based on a graded winding pack made of layers of Nb3Sn (react-and-wind) conductors. In summer 2015, a new reference baseline is issued for the DEMO- EUROfusion tokamak, leading to an update of the TF coil requirements, e.g. the operating current has been reduced from 80 kA to 63kA. Consequently, the conductor layouts for every graded layer of the TF coil winding pack is re-designed in order to match the new requirements.Each layer of TF coil winding pack has to be connected electrically in series to form the coil. The inter-layer Nb3Sn splice joint design which does not exceed the conductor dimensions is proposed in this paper for the updated 63kA Nb3Sn TF conductor. This proposed joint design allows a continuous winding of TF coil winding pack from layer to layer, housing the joint at the zone of inter-layer transition. Ultimately, the all inter-layer joints should be arranged within the winding pack at the low-field and low mechanically stressed region of D-shaped TF coil.

Determination of Air-Gap Flux Density Characteristics of Switched Reluctance Machines With Conductor Layout and Slotting Effect

This paper deals with accuracy improvement of a traditional magnetic model for saliency switched reluctance machines. The machine is with high power density for traction application. The calculation is featured by taking conductor layout and slotting effect. Fundamental characteristics, such as flux linkage and air-gap flux density, are analyzed, based on magneto-motive force (MMF) as well as magnetic permeance. Specifically in the MMF model, the winding function is featured by conductor distribution of coils in stator slots, and relation between air-gap flux harmonics and conductor layout is discussed, which helps to reduce harmonics. In the magnetic permeance model, emphases are made on the air-gap permeance fitting using a fourth-order polynomial, followed by a fitting method of magnetic saturation especially with high excitation. A finite-element method is used as a reference.

Superconductor and Cold Mass Design of the 2 T Solenoid for the PANDA Detector at FAIR

The PANDA experiment at the Facility for Anti-proton and Ion Research (FAIR) in Darmstadt, Germany, relies on a superconducting solenoid surrounding the interaction point. The magnet is designed to provide a magnetic field of 2 T over a length of about 4 m in a bore of 1.9 m. The main technical challenges are related to the need of relatively tight magnetic field uniformity (±2%) over the tracker region and to insert a warm target feed pipe transversely to the solenoid axis. To meet the given requirements while balancing the magnetic forces, the magnet is split in three interconnected coil modules. Starting from the baseline design detailed to some extent in the Technical Design Report (TDR), the conductor and cold mass layouts have been thoroughly reassessed in the last two years to increase conductor stability and to simplify coil winding and cold mass assembly, as well as cost efficiency. In this paper, the main features and updates of the conductor, cold mass design, and assembly are reviewed.

Preliminary conductor layouts for the detectors of the Future Circular Collider

For the Future Circular Collider (FCC) presently under the conceptual design at the European Council for Nuclear Research (CERN), very large conductors are needed for the detector magnets. The requested critical current is an order of magnitude higher than that of the previous generation, corresponding to about 250 kA at 4.2 K and 5 T. Characteristic conductor layouts, particularly the type and fraction of structural materials, are reviewed in order to extrapolate to the most promising designs and adapt those to the requirements imposed for the FCC detector magnets. The nominal currents required at characteristic operating conditions of 6.5 T and 4.6 K, conductor dimensions, production unit lengths and mass are investigated for defining the design of the conductor. For comparing various conductor layout options, and as a first step in the conductor R&D, it is proposed to study the conductor sizing according to relevant material characteristics.

Simplified Analytical Model and Investigation of Open-Circuit AC Winding Loss of Permanent-Magnet Machines

This paper presents a simplified analytical model based on one slot per pole for predicting the open-circuit AC winding loss of surface-mounted permanent-magnet machines accounting for the influence of tooth-tips but neglecting the redistribution effect of eddy currents. The comparison between the analytical models and finite-element results shows that the simplified analytical model has similar accuracy as the analytical model accounting for all slots together. The influence of various design parameters, such as conductor layout, slot width, slot opening width, tooth-tip height, magnet pole-arc to pole-pitch ratio, and gap between tooth-tips and conductors, on the open-circuit AC winding loss is investigated. It shows that the open-circuit AC winding loss gradually decreases with the number of radial conductor layers if the number of circumferential layers is larger than 1, although the radial segmentation is ineffective when there is no circumferential segmentation. The loss decreases greatly when the number of circumferential layers changes from 1 to 2, but reduces slowly when the conductors are further circumferentially segmented.

Preliminary Stability Analysis of the CFETR Central Solenoid Conductors

A Central Solenoid (CS) conductor layout has been tentatively decided during the conceptual design phase of the Chinese Fusion Engineering Testing Reactor (CFETR). To check the validity of the conductor layout, stability analysis must be performed against the working condition of the conductors. We constructed a superconducting critical surface of the strands used in the CS conductors and then calculated the current sharing temperature of the conductors under the most stringent working condition envisioned with the operation parameters. We further analyzed the energy margin by simulating the quenching behavior with the GANDALF code upon disturbances of different durations and lengths representative of a mechanical disturbance and plasma disruption. The analysis results give preliminary estimation of conductor stability for further improvement of the design.