Superconducting synchronous condensers have the capability of quick reactive power regulation and play an important role in maintaining the stability of renewable energy grid. In this paper, electromagnetic design of a 50 Mvar, 10.5 kV high temperature superconducting (HTS) synchronous condenser is proposed, and reactive power compensation ability is simulated. For the rotor, only the yoke is retained. The field winding adopts YBCO superconducting coated conductor, and the six racetrack coils of each magnetic pole are stacked radially in a sinusoidal shape. The stator adopts non-magnetic stator teeth, and armature windings are distributed at two layers and composed of thin Litz copper wires. According to the formula derivation and the finite element simulation model, the reactance parameters of the steady-state, transient and sub-transient operation are solved. By changing the magnitude of the field current, the reactive power output performance of the superconducting condenser is obtained. The HTS synchronous condenser is connected to the 330 kV collection station, and the transient response of the HTS synchronous condenser and the conventional synchronous condenser is compared and analyzed when a three-phase short-circuit grounding fault occurs. The simulation results validate the design scheme and provide a theoretical basis for manufacturing a prototype in the future.

The rapid progress of urbanization has led to increasing short-circuit currents in power grids, even exceeding the current interrupting capacity of the circuit breakers, which makes limiting fault currents one of the major technical and economic problems facing the power grid. As a novel high temperature superconducting fault current limiter, the composite cable-type superconducting fault current limiter adopts a hierarchical spiral symmetric winding structure for its superconducting units, offering high mechanical strength and large current-carrying capacity. With advantages such as self-triggering capability and rapid response, it has become a promising solution for suppressing high-voltage, large short circuit currents. This paper proposes a superconducting fault current limiter topology based on composite-cable superconductors, the fabrication of a 35 kV/1 kA composite cable superconducting limiter prototype, and establishes experimental platforms for testing critical current, high-voltage insulation, and impulse current impact. Insulation with stand voltage and impulse current impact tests were conducted. The experimental results validate the current-limiting performance of the prototype under steady-state current flow and high-current impact, demonstrating its ability to rapidly respond and generate quenching resistance to limit fault currents, providing important theoretical and practical support for understanding the fault current-limiting operational characteristics of composite cable superconducting fault current limiters.

This research addresses the critical need for optimized magnet power supplies compatible with High-Temperature Superconducting (HTS) magnets in fusion energy. HTS magnets are essential for generating the powerful, stable, and precise magnetic fields required in magnetic confinement fusion devices. The magnet power supply (MPS) is a critical enabling system, managing electrical energy and providing precise current regulation for these magnets. Crucially, the MPS must be specifically engineered to accommodate HTS properties and meet fusion’s stringent operational constraints. A power supply system topology incorporating full-bridge rectifier units and H-bridge modules in parallel was designed, followed by simulation validation of its output characteristics with the HTS requirements. The power supply provides ±120 V / 30 kA DC, allowing for four-quadrant operation with a current regulation precision of 0.1

Nuclear fusion energy is a sustainable and clean energy alternative and is regarded as one of the best choices to address the global energy crisis and climate change issues. Magnet power supplies are important components in fusion reactors and need to balance dynamic rapidity and stability. Based on the operating parameters of nuclear fusion magnets, this paper proposes a DC power supply topology for fusion magnets and studies its load characteristics through MATLAB/Simulink. Simulation results show that the system has the ability of operating in four quadrants, can maintain stability under different load working conditions, and respond quickly according to the action signals, verifying the feasibility of this topology. Under the condition that the control strategy is proposed, the adjustment duration of the system is approximately linearly related to the inductance of the magnet.

The three-phase coaxial high temperature superconducting (HTS) cable is a promising technology for distribution network expansion in urban center. However, the three-phase coaxial structure of the superconducting cable leads to the asymmetry of the three-phase impedance parameters, which easily cause the unbalanced current in the three-phase conductors and lead to an asymmetric operation problem. A novel two-section three-phase coaxial HTS cable is proposed firstly in China Electric Power Research Institute (CEPRI) with the phase C and shield superconducting layers are divided into two sections, each with a different winding direction, pitch and HTS tape wrapping number, so they have great technical advantages in symmetrical operating performance. For validating, A 5 m, 10 kV/1 kA two-section three-phase coaxial HTS cable is manufactured as well and this HTS cable system is supercooled by LN2 closed loop cooling system with operation temperature of 73 K. The onsite high voltage test platform is set up at a 10 kV substation in Nanjing, China. The current-carrying performances of three-phase and shield layers have been experimental tested in a 10 kV transmission line. The experimental three-phase current asymmetry rate is only 4.1% which is very close to the theoretical value of 1.64%. The comparisons verify the proposed two-section structure and provide an important basis for the practical application of this kind of HTS cable in the distribution power grid.

In the future, large-capacity SMES system is expected to play an important role in power grids, where magnet is a key component. The single tape current capacity is difficult to meet operating requirements of large-scale magnets in engineering application. Considering the magnet economic cost, it is not suitable to increase the capacity by increasing the amount of superconducting tapes and reducing the operating temperature. It is necessary to use composite superconducting conductors to increase the current carrying capacity for large-scale magnets application. This paper describes the structure and preparation process of a twisted stacked-tape in tube (TSTT) composite cable with an inner cooling channel. Then a pancake coil was fabricated using a 100-metre TSTT composite cable, and the pancake coil was cooled by liquid nitrogen immersion, with inner liquid nitrogen forced flow cooling environment. The critical current and strain of the pancake coil were measured at 77 K. With the criterion of 1 & micro;V/cm, the critical current was 650 A at 77 K. The trend and magnitude of strain in key components are generally consistent. The experimental results verify the rationality of the design of this TSTT composite cable and provide a valuable reference for large-scale magnet design.

High-temperature superconducting (HTS) tokamak is significantly smaller in size than low-temperature superconducting (LTS) tokamak. A HTS toroidal field (TF) coil will be manufactured to study the feasibility of HTS tokamak. To ensure the safety of the TF coil, a preliminary design of quench detection system (QDS) has been completed. The QDS consists of a primary detection system and a secondary detection system. The primary detection system based on voltage signal employs co-wound LTS wire and balanced bridge method to mitigate induced voltage noise. To prevent the quench signal from going undetected, a secondary detection system based on radio-frequency reflected wave signal and thermal-hydraulic signals is designed to ensure the safety of the TF magnet system.

The level of fault current grows rapidly as more and more distributed renewable energy is connected to the grid in recent years. With the aims of preventing the growing levels of fault current in power grid and addressing the drawbacks of conventional relay protection, superconducting fault current limiter (SFCL) with fast current-limiting response, low loss and quick recovery time is being developed to tackle the challenges. Herein, a design and prototype of a magneto-biased SFCL (MBSFCL) with two-stage fault current limiting capability is presented. The grid-connected test of the MBSFCL prototype has been carried out in a 66 kV power substation . The results are obtained by AC withstand voltage test and a 7-day steady-state operation test of MBSFCL, which verify the feasibility of MBSFCL in grid application.

The rapid urbanization has led to a surge in short-circuit currents within the electrical grid, occasionally surpassing the interrupting capacity of circuit breakers. This challenge underscores the critical need to limit fault currents, representing a significant technical and economic issue for power grid management. Superconducting fault current limiter (SFCL) has the advantages of fast current limiting response, self-triggering, low loss and fast recovery, which is an effective solution to the short-circuit current problem. However, the existing SFCLs used in power grids have the problem of costing large amount of superconducting materials, which cannot meet the cost requirements of current limiting in medium and low voltage level lines. The SFCL with current-limiting CORC conductor has higher current-carrying capacity and lower production cost, which is expected to further enhance the reliability and economy of current limiting. Aiming at the current-limiting CORC conductor applied for a 35 kV/1.5 kA SFCL, an FEM model with electric, magnetic, fluid and thermal fields is established in COMSOL Multiphysics so as to explore the multi-field coupling mechanism under steady state and fault condition. Simulation results obtain the critical current, AC loss and magnetic field of the CORC conductor in steady state. Furthermore, The quench operation of the CORC conductor is performed by applying a fault RMS current of 17.5 kA and 1750 A to acquire its electromagnetic and thermal-fluid operation stability. This study explores the application prospect of CORC cable in SFCL and impels the practical application of SFCL.

High-temperature superconducting (HTS) tokamak is significantly smaller in size than low-temperature superconducting (LTS) tokamak. A HTS toroidal field (TF) coil will be manufactured to study the feasibility of HTS tokamak. To ensure the safety of the TF coil, a preliminary design of quench detection system (QDS) has been completed. The QDS consists of a primary detection system and a secondary detection system. The primary detection system based on voltage signal employs co-wound LTS wire and balanced bridge method to mitigate induced voltage noise. To prevent the quench signal from going undetected, a secondary detection system based on radiofrequency reflected wave signal and thermal-hydraulic signals is designed to ensure the safety of the TF magnet syste

Multi-layer spiral compact cable based on high-temperature superconducting tapes is a potential candidate for large-scale superconducting applications. During magnet processing and operation, superconducting tapes and cables are subject to complex mechanical and electromagnetic forces. Plentiful studies are conducted on the cable's mechanical performance during the preparation process and the operating electromagnetic characteristics separately, but still lack sufficient focus on the electromagnetic-mechanical coupling. In this paper, an electromagnetic-mechanical field co-simulation is carried out. The effect of residual strain from the winding process is included. The electromagnetic force characteristics in spiral cables as well as mechanical response are studied. This study is fundamental for further analysis on large-scale magnets made of spiral cables that are subject to large Lorentz forces in operation with preparation-induced residual strain.

Superconducting synchronous condensers have the capability of quick reactive power regulation and play an important role in maintaining the stability of renewable energy grid. In this paper, the structural and electromagnetic parameters of a 50 Mvar, 10.5 kV high temperature superconducting (HTS) synchronous condenser are designed. For the rotor, only the yoke is retained, forming an air-core superconducting rotor. The field windings are made of rare earth barium copper oxide (REBCO), cooled by helium gas and operate at the temperature of 30 K. The rated no-load field current is in consideration of the maximum magnetic field at the end of the field windings, so that quench can be suppressed. As for the stator, non-magnetic stator teeth are adopted, and the armature windings are supported by epoxy resin, which can effectively restrain the ferromagnetic teeth from saturation. The armature windings are distributed at two layers and composed of thin Litz copper wires. The internal magnetic field distribution of the superconducting synchronous condenser is preliminarily obtained by constructing a two-dimensional (2-D) finite element model. It is found that the maximum magnetic flux density in the air gap is 1.6 T, and the no-load electromotive force (EMF) varies linearly with the field current. The simulation results validate the design scheme and provide a theoretical basis for manufacturing a prototype in the future.

Understanding the physiological effects of herbicides on crops is crucial for crop production and environmental management. The effects of 4-hydroxyphenylpyruvate dioxygenase inhibitor (HPPDi) herbicides at different concentrations on chlorophyll content in maize leaves, fresh weight of roots, stems and leaves, and fluorescence substances and functional groups in root exudates (REs) were studied by UV-Vis absorption spectroscopy, fluorescence spectroscopy, Fourier transform infrared spectroscopy (FTIR) and two-dimensional correlation analysis (2D -COS). The results showed that 5 mg/L and 10 mg/L HPPDi herbicides inhibited the synthesis of chlorophyll in maize leaves. The weight of roots, stems and leaves of maize after application was lighter than that of the control group. HPPDi herbicides affected the early growth of maize seedlings, and the effect was most obvious at high concentration. Synchronous fluorescence spectrum and three-dimensional (3D) fluorescence spectrum revealed that the fluorescence intensity of protein, fulvic acid and humic acid in maize REs changed prominently. With the increase of HPPDi herbicides concentration, the fluorescence intensity decreased gradually. Through FTIR and 2D -COS, functional groups such as C -H, C--O, Cl, NO3-, C -O and O -H were found to participate in the interaction between HPPDi herbicides and maize REs as binding sites. C -O, C-Cl and C -C have the strongest binding ability, while C--C and C--O of aromatic rings, quinones or ketones first take part in the binding between HPPDi herbicides and maize REs. The results can provide a theoretical basis for evaluating the safety of HPPDi herbicides on maize and a method for discovering the effects of pesticides on environmental media and plant physiological effects.

Mesotrione, topramezone, tembotrione, and sulcotrione are four types of 4-hydroxyphenylpyruvate dioxidase (HPPD) inhibitor herbicides that are extensively employed in agricultural practices, but their usage also leads to environmental pollution and poses risks to human health. A probe (E)−1-((2-(pyridin-2-yl) hydrazineylidene) methyl) naphthalen-2-ol (CHMN) based on chelation enhancement (CHEF) effect synthesized. CHMN was first chelated with Zn2+ to form a probe system with green, which can be further used to detect mesotrione, topramezone, tembotrione and sulcotrione in complicated environment. CHMN-Zn2+ detection of four pesticides was accurate, with an excellent linear relationship between 0 and 100 μM. The detection limits were LODmesotrione = 7.79 μM, LODtopramezone = 1.91 μM, LODtembotrione = 1.38 μM and LODsulcotrione = 2.43 μM. The detection time is 1 min, and it is successfully applied in real water sample and bioimaging. This work can provide a novel method for studying the migration and behavior of environmental pollutants.

In order to address the issue of short-circuit fault current limiting in DC power grids, this paper employs a new topology structure of magneto-biased superconducting DC current limiting device with characteristic of automatic triggering, multi-level current limiting, and fast recovery. The current constraining effect was simulated and examined using MATLAB/Simulink platform in DC distribution network models under 10kV voltage level with short-circuit fault at different position. The results show that the current limit effect will change with the location of the bipolar short-circuit fault. In the early stage of fault occurrence, the maxmium current amplitude can be reduced by 20%, and the time when current peak appears will advance, providing important theoretical basis for the factual implementation of superconducting current limiters in DC grids in the near future.

Prothioconazole (PTC) is currently a popular triazole fungicide. In recent years, as the use of PTC has increased, there has been growing concern about its environmental and toxicological effects. Here, we studied the effect of PTC on the growth of soybean plants and further analyzed the enzyme activity and microbial community of rhizosphere soil after PTC treatment through 16S rRNA gene high-throughput sequencing and fungal ITS. Changes in structural diversity and species richness were measured using Simpson’s diversity index, Shannon’s diversity index and the Chao1 and ACE algorithms. The statistical t-test was applied to test whether the index values were significantly different between the two groups. The results showed that the contents of malondialdehyde (MDA) and H2O2 increased after the recommended dose of PTC, indicating that PTC has a strong toxic effect on plant growth, thus affecting the healthy growth of plants. In the presence of PTC, the species richness of fungi and bacteria decreased in all three soil types (black soil, yellow earth and red earth), and the community structure also changed significantly (the p-values were all less than 0.05). Proteobacteria, Actinomycetota, Bacteroidota and Acidobacteriota were the main bacteria, and the abundance of Acidobacteriota and Chloroflexi increased. The dominant fungal communities were Ascomycota and Mortierellomycota. The increased abundance of potentially beneficial microorganisms, such as Sphingomonadaceae, suggested that plants may be resistant to PTC stress by recruiting beneficial microorganisms. PICRUSt analysis showed that the metabolism-related functions and membrane transport pathway of rhizosphere bacterial community were inhibited after PTC stress. Spearman correlation analysis revealed a weak correlation between key fungal taxa and rhizosphere variables in the presence of PTC. Therefore, compared with those in the fungal community, the bacterial community was more likely to help plants resist PTC stress, indicating that these key fungal groups may indirectly help soybean growth under PTC stress by affecting the bacterial community.

In the paper, the overall structure and electromagnetic design parameters of a new high temperature superconducting (HTS) synchronous condenser with a capacity of 50Mvar is preliminary presented. Stator and rotor as well cooling method of the HTS condenser is introduced in detail, and a two-dimensional simulation model is established by finite element method (FEM) for analyzing electromagnetic characteristics. As the result, the air gap flux density of the HTS synchronous condenser is closely to 1.6T, and the electromotive force (EMF) increases linearly with exciting current.

The rapid pace of urbanization has significantly elevated short-circuit currents in the grid, often surpassing the interrupting capacity of circuit breakers. This has turned limiting fault currents into a significant technical and economic challenge for the power grid. The superconducting fault current limiter (SFCL) offers distinct advantages, including a rapid current limiting response, self-triggering capabilities, minimal losses, and fast recovery. However, current SFCLs used in power grids face challenges related to the substantial use of superconducting materials, which usually exceeds cost constraints in medium and low voltage lines. The high temperature superconducting (HTS) Conductor on Round Core (CORC) cable offers superior mechanical properties and exceptional current carrying capacity. Therefore, the SFCL that utilizes the CORC conductor for current limiting boasts higher current capacity and lower production costs, enhancing both reliability and cost-effectiveness. To ensure the safety and efficiency of the CORC conductor, critical factors such as the critical current and alternating current (AC) loss must be considered when HTS CORC conductors are applied on alternating currents. This paper presents a numerical analysis of the electromagnetic field within an HTS CORC conductor that comprises six superconducting tapes with reversal winding and a stainless steel sheath. The analysis is based on the T-A formulation and finite element method (FEM). The findings indicate the critical current of this CORC conductor is 1070 A. Furthermore, the study reveals the impact of applied current and self-field on AC loss variations and branch shunting between the superconductor layer and stainless steel sheath: when the applied current exceeds 3000A, the current of the sheath layer will exceed that of the HTS layers, achieving the effect of shunt protection. This study paves the way to investigate the feasibility of CORC conductor working for an SFCL.

The DC superconducting energy pipeline (DC SEP) is a promising technology, which has the ability to transmit electricity and fossil energy such as liquefied natural gas (LNG) at the same pipeline so that LNG could serve as the refrigerant for the high-temperature superconducting (HTS) cables.The collaborative transportation of electricity and LNG increases the efficiency while lowering the cost.However, the operation performance of the SEP, which is crucial for HTS cables and LNG, is of greater complexity on account of multi-physics interactions.Herein, a ±100 kV/1 kA SEP model with electric, magnetic, fluid and thermal fields is established in COMSOL Multiphysics to analyze the temperature distribution of SEP via parametric scanning on SEP heat leakage and LNG flow rate.Finally, the relationship between temperature rise and LNG flow rate of a SEP has been estimated based on the interactions of the multi-physics fields.The results indicate that the temperature rises by 11.6 K for every kilometer of SEP.Moreover, the influences of heat leakage and LNG flow on temperature rise are revealed.Temperature rise increases proportionally with heat leakage and it decreases not monotonously with LNG flow rate.This study validates the feasibility of SEP and provides the theoretical references for the demonstration of SEP.

High temperature superconducting conductor on round core (CORC) cable has superior mechanical properties and current carrying capacity. With the purpose of ensuring the safety and efficiency of CORC cable, the critical current and the AC loss should be considered when alternating current is applied on CORC cable. In this paper, the electromagnetic field of a high temperature superconducting CORC cable wound by six superconducting tapes with reversal winding is numerically calculated using the T-A formulation and FEM. Results indicate that the critical current is 1070 A, and the variation of AC loss according to applied current and self-magnitude is revealed.