Internal Conductor Research Articles

Analisis Gangguan Penyulang Dengan Menggunakan Diagram Pareto dan Diagram Fishbone di UP3 di Bojonegoro

Feeder interference is an important problem in the electricity system because it can cause unplanned blackouts. With society's increasing need for electricity, it is very important to understand the components that cause feeder interference. Feeder problems can be caused externally or internally. This research was used to determine the level of causes of feeder disturbances at UP3 Bojonegoro and also the root causes of these disturbances. To realize the objectives of this research, this research uses Pareto and fishbone diagrams. The highest level of problems lies in internal factors, namely insulators, conductors and arresters. Meanwhile, external factors are the result of animals and residents' activities. Then, for employment factors that influence feeder disruption, such as lack of practice regarding maintenance or restoration. Therefore, this research contributes to efforts to maintain the sustainability of the electricity system, with the hope of providing a better view of this problem and motivating the implementation of more effective preventive measures.

Seismic Performance Evaluation and Retrofit Strategy of Overhead Gas-Insulated Transmission Lines

The overhead gas-insulated transmission line (GIL) in ultra-high-voltage converter stations, distinct from traditional buried pipelines, demands a thorough investigation into its seismic behavior due to limitations in existing codes. A refined finite element model is established, considering internal structure, slip between various parts, and the relative displacement at the internal conductor joint. Seismic analysis reveals the vulnerability of the GIL at the corner of the pipeline height change, with two failure modes: housing strength failure and internal conductor displacement exceeding the limit. Furthermore, the acceleration amplification coefficient of the support generally exceeds 2.0. Two retrofit methods, namely increasing the fundamental frequency of all supports and fixing the connections between all supports and the housing, have been proposed. The results indicate the effectiveness of both methods in reducing the relative displacement. Fixing all the supports effectively reduces the stress, whereas the other one yields the opposite effect. The seismic performance of a GIL is determined not by the dynamic amplification of supports, but by the control of relative displacement between critical sections, specifically influenced by the angular deformation of the pipeline’s first-order translational vibration mode along the line direction. Seismic vulnerability analysis reveals a reduction of over 50% in the failure probability of the GIL after the retrofit compared to before the retrofit, with the PGA exceeding 0.4 g.

Impact of temperature asymmetry and small fraction of static positive ions on the relaxed states of a relativistic hot pair plasma

Abstract The relaxed state of a magnetized relativistic hot plasma composed of inertial electrons and positrons having different relativistic temperatures and a fraction of static positive ions is studied. From the steady-state solutions of vortex dynamics equations and the relation for current density, a non-force-free triple Beltrami (TB) relaxed state equation is derived. The TB state is characterized by three scale parameters that consequently provide three different self-organized structures. The analysis of the relaxed state shows that for specific values of generalized helicities, the disparity in relativistic temperature and the existence of a small fraction of static positive ions in pair plasma can transform the nature of scale parameters. Moreover, an analytical solution of the TB state for an axisymmetric cylindrical geometry with an internal conductor configuration demonstrates that due to asymmetries of temperature and density of plasma species, diamagnetic structures can transform into paramagnetic ones and vice versa. The present study will improve our understanding of pair plasmas in trap-based plasma confinement experiments and astrophysical environments.

Pool-Based Tow System for Testing Tethered Hydrokinetic Devices Being Developed to Harvest Energy From Ocean Currents

Abstract The immense potential for ocean current energy harvesting is being actively explored as the push for renewable energy becomes more urgent. This paper demonstrates a tow testing platform built to examine and validate mathematical models related to the performance of tethered, underwater, hydrokinetic devices in development to harvest energy from ocean currents, and presents experimental results illustrating how such a system can be used. The platform has been modularly designed to allow for the testing of various tethered, underwater energy-generation systems, including kite-based systems, coaxial turbines, and duct sails. Previous research on tethered energy-generating systems has primarily been focused on airborne systems. Additionally, the limited experimental research on tethered, underwater energy-generation systems has relied on a rigid rod for mechanical and electrical connections between the test articles and instrumentation. The tow testing platform presented in this paper accomplishes the mechanical and electrical connection through a dual-function tether, featuring internal conductors and an external sheath to support towing loads. The goal of this platform was to enable the emulation of ocean currents, which are largely unidirectional, and to retrofit a regular pool into a cost-effective, adaptable, small-scale tow tank test bed. The capabilities of the system include two-way communication with tethered devices, multiple towing profiles in order to emulate different flow regimes, real-time control, and differential velocities via dual winch operation.

State evaluation technology of distribution network cable based on novel internal conductor temperature measurement

To evaluate insulation status of power cables and improve cable transmission utilization, a novel measurement and control system for intelligent cable (MCIC system) is designed and manufactured. In MCIC system, the multimode fiber is placed into cable conductor, cable connectors and terminals when power cable was manufactured in the factory. The axial temperature data of cable conductor can be measured directly in operating cable by the MCIC system platform. MCIC system has two innovative functions: dynamic calculation of power cable ampacity and regulation of electric energy in relevance region. Analysing the changing rules of environmental temperature, cable insulation temperature and corresponding current, the realtime maximum cable ampacity list can be obtained by iterative computations. According to the ampacity list, the operators can exactly acquire the real-time maximum currents every power cable line and regulate the conveying current values accurately. Furthermore, the concept of electric load balance in a region is realized in the MCIC system. Some testing data from MCIC system established in Shenzhen demonstrate that conductor temperature can quickly respond to changes in cable load, and the real-time cable carrying capacity can be online caculated.

Progress in engineering design of CFETR toroidal field superconducting magnet

China Fusion Engineering Test Reactor (CFETR) is a national scientific research project which is aimed to initially build fusion energy production up to 2×108 W and to eventually reach relevant power level 1×109 W of DEMO. The major and minor radius of CFETR are 7.2 m and 2.2 m, respectively. As one of the most important components, a full-sized CFETR Toroidal Field (TF) magnet was designed. The height and width of the TF magnet are 21.3 m and 12.4 m separately. To provide 6.5 T at plasma center, TF magnet operates at a current of 95,600 A/turn. In this paper, engineering design of TF coil case (TFCC) is firstly introduced. And the structural design of internal joints, external joints, conductor, and insulation system of TF winding pack (WP) is presented. Based on the thermal load, the cooling system is also designed. Finally, some auxiliary structures are designed to ensure the normal operation of TF magnet.

Relaxation of multi-ion plasmas in an internal conductor

The possibility of the formation and characteristics of the relaxed structures in the multi-ion magnetized plasmas consisting of heavy ions, light ions, and inertia-less electrons have been explored. Using the vortex dynamic equations with the current density, the system is relaxed to triple Beltrami states. Solutions of the relaxed states are determined in two different cases: (i) simple slab geometry and (ii) slab geometry with an internal conductor. The impact of Beltrami parameters and density ratios of the plasma components on the formation of equilibrium structures in both geometries has been studied. Moreover, we also highlight the equivalences of both geometries (simple slab geometry and a slab geometry with an internal conductor). This investigation will be useful for studying and understanding the relaxed structures in different astrophysical objects such as solar wind, Earth’s ionosphere, near-Earth plasmasheet, upper ionosphere, and Saturn and in the laboratory plasmas having two positively charged ions of different masses. Moreover, this work will be helpful in describing the underlying physics of the relaxed structures. These structures are developed in different astrophysical bodies that revolve around the planet such as Jupiter magnetosphere.

The influence of wellhead stick-up on the analysis of critical stress points on conductor casing

During the subsea well construction and workover, a subsea well is connected to the drillship through the blowout preventer (BOP) and the drilling riser. Environmental loads acting on the drilling riser and the drillship are transferred to the wellhead, conductor, and casings, which can cause fatigue issues at critical points such as at the casing couplings. The main function of a subsea wellhead system is to perform the interface between the BOP and the well, ensuring its integrity throughout its operational life. Factors such as the increase in the weight and height of the BOP on 6th generation platforms contributed to the increased risk of failure due to fatigue. The system in this work is represented by a 3D finite element model including internal cement, conductor, and surface casings. Although simplifications were adopted in the modeling, the essence of the well physical behavior remains. The work addresses the influence of the wellhead stick-up on the maximum stress in the conductor below the seabed, comparing analyses of two wellhead stick-up and including horizontal displacement resulting from the integration of the platform/riser dynamics. These horizontal loads are transferred to the top of the wellhead system as a bending moment and shear force. A time series containing riser horizontal loadings is utilized to obtain the von Mises stress. This information is used to count cycles with the rainflow counting technique. The number of cycles resulting for the two wellhead stick-up is compared and demonstrates how wellhead stick-up can be influenced by an increase in dynamic loads acting on the wellhead top. An influence can be observed on the maximum stress point of the conductor located below the seabed. From these results, it was possible to conclude the wellhead stick-up can influence the depth of a critical point in the conductor below the seabed.

The Study on a New Method for Detecting Corona Discharge in Gas Insulated Switchgear

Partial discharge (PD) is the main cause of insulation deterioration and failure of gas-insulated switchgear (GIS). Corona discharge (CD) is a typical type of PD in gas-insulated switchgear. Accurate and sensitive measurement of CD in GIS is of great significance for theoretical research in the laboratory and fault prediction of GIS in the actual operation. A novel method for detecting CD in GIS is proposed in this article. A coaxial structure model for simulating GIS is established. The CD detecting sensor based on the proposed method is designed for this model. An artificial tip defect is designed on the internal high voltage conductor of the coaxial model to simulate CD in GIS. A 50 Hz ac power supply, a dc negative power supply, and a dc positive power supply are applied as excitations to generate the CD at the defect, respectively. The discharge pulse signal is detected by the proposed sensor. The results show that the proposed sensor can completely obtain the information of the CD pulse signal. The proposed method has the same anti-electromagnetic interference ability as the ultrahigh-frequency method and has a high sensitivity to CD in GIS.

Погрешность измерения диэлектрической проницаемости проводящих сред широкополосным методом

The measurement of the complex dielectric permittivity (CDP) of nine calibration liquids with static permittivity from 2.38 (toluene) to 78.5 (water) was carried out. The decision to select the dimensions of the coaxial cell used in the measurement of the CDP of conducting media by the broadband method in the frequency range from hundreds of hertz to 8 GHz is justified. It is shown that the use of a cell with the dimensions of the external and internal conductors of 16 mm and 6.97 mm, respectively, in comparison with a cell with the dimensions of 7 mm and 3.02 mm reduces the frequency of influence of electrode polarization. The relations of the measurement error of the real part of the CDP in the low-frequency range with the loss tangent for liquids with different specific electrical conductivity are found.

Formation of self-organized structures in internal conductor plasma

A possibility of the confinement of two-fluid (electrons and ions) magnetized plasma in a simple cylindrical configuration as well as in a cylindrical geometry with an internal conductor is analyzed. By controlling the characteristics roots of Triple Beltrami state the formation of diamagnetic and paramagnetic structures is investigated for a simple cylindrical geometry. For an internal conductor system, the nature of relaxed structures is only paramagnetic. These paramagnetic structures are independent of the type of the characteristics roots. The results of the present investigation will be helpful to explain the equilibrium structure in the astrophysical objects such as Jupiter magnetosphere which is co-rotated with the planet and in the laboratory.

Internal temperature measurement and conductor temperature calculation of XLPE power cable based on optical fiber at different radial positions

To investigate the optimal radial-arranged-position of the optical fiber in the cross-linked polyethylene (XLPE) power cable, the fibers were arranged into three positions, including segmental conductor center, the insulation shield surface, and the waterproof compound center, respectively, and temperatures were measured based on the Brillouin optical time-domain reflectometry (BOTDR) technology while the thermocouples were arranged at the same positions mentioned above for comparison, respectively. Four cases of cable temperature rising experiments under the laying environments of duct and water were carried out. The conductor temperatures were calculated using the temperatures measured by the fibers at the insulation shield surface and waterproof compound center, and the differences between the calculated values and the measured temperatures by thermocouples were analyzed and compared. Results show the temperature differences at different axial positions of fibers at the insulation shield surface or the waterproof compound center were less than 0.22 °C. These were much less than the differences in different axial positions of thermocouples, among which the maximum is 4.8 °C. The maximum temperature differences between the fibers and the thermocouples at the three positions mentioned above were 4.9 °C, 3.2 °C, and 3.7 °C, respectively. The maximum transient relative differences of the conductor temperature between the calculated and measured values do not exceed 7.6% and 7.1%, respectively. And the steady-state relative differences do not exceed 2.6% and 4.7%, respectively. The insulation shield surface and waterproof compound center are recommended as the optical fiber arranged-position for calculating the conductor temperature.

Functionalized Three-Dimensional Multilayer Ceramic Modules

Three-dimensional interconnect devices are still strongly related to plastic materials. Since the use of these materials is limited in harsh environments, there is an application gap, which could be filled by ceramic circuit carriers. Low-temperature cofired ceramics (LTCC) offer promising solutions to fill this gap. This work provides a feasibility study, including the whole technological chain of ceramic multilayer processing. Targeting a curved multilayer substrate, fully equipped with SMD (Surface-mounted device) components, the particularities of single process steps are investigated. Two shaping methods based on quartz glass molds are compared with regard to shape fidelity and technological effort. The investigation of internal conductor lines and via connections reveals that the metallization should have a minimum width of 200 µm and the via diameter is limited to 150 µm. Further considerations focus on the possible footprint of components and use of cavities to increase the footprint of components. The limits of wire bonding on curved surfaces were inspected. Finally, the work presents a demonstrator of a fully equipped four-layer ceramic circuit, including internal wiring. Hence, the transfer of the 2.5-dimensional multilayer ceramic technology into the third dimension is proven.

Carbon quantum dots-based semiconductor preparation methods, applications and mechanisms in environmental contamination

Photocatalyst is the most widespread method in advanced oxidation technologies, but due to the photo-induced electron combine easily with hole and the wavelength of adsorption is limited which will affect some practical applications. Carbon quantum dots (CQDs) is non-toxic and harmless green materials, it has the ability to improve the photocatalytic effect which is attributed to its good electrical and optical properties. Their up-conversion effect, photosensitization and electrical conductivity are assistants which help promote the photocatalytic effect in environmental applications. The key mechanisms of CQDs to improve photocatalysis can be roughly divided into three categories: 1) Up-conversion effect converts the incident light into the emitted light with high energy to solve the problem which is the light absorption range; 2) CQDs act as a photosensitizer instead of valence band to provide electrons to the conduction band of semiconductor; 3) CQDs can be used as the internal or external electronic conductor in materials to alleviate the trend of electron and hole separation. However, CQDs and CQDs-based photocatalysts have different views to solve environmental problems, so it is necessary to integrate different views. Therefore, this review is mainly aimed at the recent researches about the preparation processes of CQD, CQDs-based photocatalysts, and their ability to remove environmental pollutants, with a special emphasis on the mechanism for depredating pollutants. Furthermore, this paper analyzes and discusses the prospects and challenges of CQDs in the environmental field.

Analyses of the plastic deformation of coated conductors deconstructed from ultra-high field test coils

REBCO coated conductors are now being used for building very high-field magnets with large electromagnetic stresses, both expected ones due to transport current × stresses and additional stresses resulting from the large screening currents inherent in wide tapes. Post mortem analyses of several recent test coils operated above 40 T show that significant conductor plastic deformation occurs, even for JBR stresses well below the ∼1 GPa yield of the Hastelloy substrate of the conductor. To investigate these deformation mechanisms, conductors were unwound after coil test and carefully examined with respect to their length-wise Ic which revealed many areas of local damage. Regions of interest were examined by metallographic cross-section, Hall microscopy, magneto-optic imaging and scanning electronic microscopy. Important damage frequently occurred to the outer edges of pancakes in the coil ends, which were often plastically deformed over the whole turn circumference, especially when this outer edge was a slit edge. Internal conductor damage was also seen, especially delamination between the buffer and REBCO layers at slit edges. Careful sectioning of the tape at ∼10 mm intervals showed that the plastic deformation of the turns was complex and variable around the turn circumference, with tape cross-sections that exhibited continuous shape change in the outer turns. The bending center line of tapes often shifted from the tape center line toward the edge closest to the coil center, indicating asymmetric effects of transport and screening current stresses across the conductor width. A surprising and vital result is that damage was prevalent when the slit edge was also the edge at which transport current flowed. This damage was absent when the transport current flowed at the not-slit edge, implying great sensitivity of the effect of screening current stresses to localized conductor damage.

Microstructural study on Sn–Zn/Cu–Ti diffusion reaction for internal tin Nb3Sn conductor development

To take advantage of Zn and Ti doping effects on improvement of diffusion behavior in the Sn–Cu mixing step and the Nb3Sn layer formation for the internal tin process, a diffusion couple configuration of Nb/Cu–Ti/Sn–Zn has been proposed. In this work, a fundamental study on the diffusion behavior of Sn–Zn/Cu–Ti, with different heat treatments, was conducted to aid in a better understanding of Nb3Sn phase formation, via internal tin diffusion. The first feature is that at 210∘C, the γ-CuZn phase forms at the reaction interface of Sn-20 wt%Zn and Cu, following which the β-CuZn and η-CuSn phases form at 400∘C. Compared with the Sn/Cu-12 wt%Zn system, Kirkendall voids appear to be suppressed, as few ε-CuSn phases, in which many voids grow, form in the Sn–Zn/Cu system. At 550∘C, a dendritic mixed phase of α-CuZn and δ-CuSn phases form. At this temperature, Sn appears to diffuse faster than in the case of the Sn/Cu–Zn system. It is observed that, after heat treatment at 550∘C, very fine compound particles of Sn–Ti are homogeneously distributed in the outer regions originally known to be the Cu–Ti sheath area. In the multifilamentary wires consisting of Nb/Cu–Ti/Sn–Zn diffusion couple configuration, no Ti rich compound layer was formed at the boundary of the Nb sub-elements, which overcomes the problem to suppress a smooth Sn and Ti diffusion into the Nb sub-element, when Ti is doped to Sn cores. Thus, no Ti-rich compound layer segregation, few void formations in the Sn–Cu mixing step and distributed fine Sn–Ti particles in the matrix accounts for the improved Jc characteristics in Nb/Cu–Ti/Sn–Zn wires. With regards to the mechanical properties, alloying of 20 wt% Zn to Sn cores increases the Vickers hardness of the Sn core to approximately 20kgf/mm2, almost double that of pure Sn or Sn-alloys with a small amount of Ti.

High-Voltage Collet of the Nuclotron Injection Kicker

The design of a high-voltage collet with movable external and internal conductors is considered. The design of the grip connection, the choice of material for the grips, and the conditions for ensuring reliable electrical contact in it are described in detail. The results of tests of the high-voltage collet are presented.

Test Analysis and Simulation Calculation of Temperature Field for Dry-Type Air-Core Reactor

Based on test analysis and simulation calculation of temperature field for dry-type air-core reactor, the temperature rise rule of internal axial dimension and enveloping internal conductor were analyzed. The highest temperature rise point in the envelope is located about 1/4 of the packet seal. The temperature rise difference between the inner wires is small, and the temperature rise difference within the envelope is less than 1 °C. The radial distribution of temperature along the insulating impregnated glass fiber has a great gradient. The temperature in the middle of the airway is near room temperature, and the temperature rise is about 5K, and the internal temperature of the airway has a larger gradient. For airway width design, the influence of the change of the airway width of the temperature rise distribution should be considered.

Effect of Zn addition and Ti doping position on the diffusion reaction of internal tin Nb3Sn conductors

Addition of Zn to a Cu matrix during Cu–Zn/Sn interdiffusion reactions at 400 °C leads to the formation of a solid ternary Cu–Zn–Sn phase, β-CuZn, at the outermost reaction layer next to the porous ε phase. The use of a brass matrix considerably suppresses void formation and promotes homogeneous outward Sn diffusion in pre-annealing, prior to Nb3Sn formation. There are exactly three paths for Ti doping in the internal tin process, i.e. doping to Sn cores, Nb filaments, and Cu matrix. Ti doping to Sn cores causes a Ti-rich layer formation at the boundary of the Nb filament pack; however, no Ti-rich layers are formed as a result of small Ti doping to the matrix and to Nb filaments. The absence of Ti-rich layers is believed to contribute to a smooth Sn diffusion and suppression of void growth. Atom probe tomography measurements reveal that Ti doping to Sn cores leads to a more inhomogeneous Ti distribution near the grain boundary and a larger variation of the grain boundary thickness than doping to Nb filaments, which may contribute to a better Sn grain boundary diffusion. It is concluded that Ti doping to the matrix, instead of doping to Sn cores, might be more effective in maintaining better growth kinetics of Nb3Sn.

Study on the ampacity of single-core submarine power cable with return conductor

In order to analyze the effect of internal Cu return conductor on ampacity, this paper establish three types of single core submarine power cable and calculate losses and thermal resistances. Results show that the internal return conductor can effectively reduce the cable loss, thereby increase the cable current carrying capacity. Cable with separated return conductor shows highest ampcity. When section area of return conductor increases, ampacity of cable improves correspondingly.