HTS SMES Research Articles

AC Loss Calculation on a 10 MJ/5 MW HTS SMES with Hybrid Winding Structure

AC Loss Calculation on a 10 MJ/5 MW HTS SMES with Hybrid Winding Structure

Electromagnetic optimization of a hybrid toroidal magnet for 10 MJ HTS SMES system

Electromagnetic optimization of a hybrid toroidal magnet for 10 MJ HTS SMES system

Engineering Design of 1 MJ HTS SMES System With kA-Level Current Capacity for NICA Accelerator

Engineering Design of 1 MJ HTS SMES System With kA-Level Current Capacity for NICA Accelerator

Study on HTS SMES Coil for Optimized Dimensions

Study on HTS SMES Coil for Optimized Dimensions

Mechanical characterization of a 10-MJ HTS SMES magnet wound by quasi-isotropic strands and directly stacked tape conductors

Mechanical characterization of a 10-MJ HTS SMES magnet wound by quasi-isotropic strands and directly stacked tape conductors

Cooling plates heat loss estimation for 50 kJ HTS SMES using coupled magneto-thermal transient analysis with a varying ramp rate

Cooling plates heat loss estimation for 50 kJ HTS SMES using coupled magneto-thermal transient analysis with a varying ramp rate

Frequency-Domain Analysis and the Effect on Voltage Distribution of the HTS SMES

The high-frequency PWM pulse voltage of SMES power conditioning system (PCS) transmitted to the HTS magnet will influence the security of the magnet. Therefore, to analyze the dynamic response of the magnet with the interaction of the PWM pulse voltage is necessary for the SMES operation. This paper proposes a frequency-domain analysis method for the transient characteristic of the HTS magnet, which can be utilized to analyze the voltage distribution and the frequency response characteristic of the magnet. To evaluate the effectiveness of the proposed method, a sample HTS magnet is assembled to measure its voltage distribution characteristic. Furthermore, the results of amplitude-frequency characteristics coincide with the trend of magnet voltage variation.

Dimension Reduction Calculation Method of Toroidal Magnet

For the high temperature superconducting magnetic energy storage (HTS SMES) magnet with large capacity, in order to reduce the leakage magnetic field and the vertical magnetic field component on the wire, it mostly adopts the toroidal magnet structure. However, this structure has imposed new challenges in calculating the AC loss of the magnet. Due to the particularity structure of the toroidal magnet, that is, its magnetic field is not distributed in the 2D axisymmetric manner, it is impossible to calculate the AC loss in the toroidal magnet with a traditional 2D computation model. At the same time, the 3D model has its problems, such as the modeling is complicated; the calculation efficiency is low; the demand for computation is enormous, and so on. In order to provide a solution for calculating the AC loss in the magnet with a non-2D axisymmetric distributed magnetic field, a method of “dimensionality reduction and inversion” is proposed. In this method, the magnetic field distribution in the toroidal magnet is calculated by using a 3D model intended for uniform flow, and the AC loss is calculated by using a 2D model. The practical application shows that this method can provide a solution for calculating the AC loss in the magnet with a non-2D axisymmetric distribute magnetic field, and the calculated results meet the requirements of engineering calculation.

Design and Characteristic Study of a Novel Internal Cooling High Temperature Superconducting Composite Cable With REBCO for Energy Storage Applications

High temperature superconducting magnetic energy storage systems (HTS SMES) have attracted significant attention for fast response and ensure a reliable power supply. However, the current carrying capacity of single superconducting tape often meets limitation for the large scale HTS SMES applied in the power grid. Therefore, a high temperature superconducting composite cable with inner helical cooling tunnel and kA class current carrying ability is proposed for SMES magnet by using REBCO tape. The critical current characteristics of this internal cooling composite cable are analyzed considering the influence of anisotropy in magnetic field. A 100 m length, high temperature composite cable is manufactured in China Electric Power Research Institute (CEPRI). The critical current experimental system with a 3 kA DC current power source and a high-precision Digital Data Acquisition system have been set up to investigate the current carrying ability of a straight and a bending demo composite cable in LN2. The results show that critical current of HTS composite cable consisted of 4 REBCO tapes can achieve 780 A at 77 K self-field and the experimental I–V curve of each REBCO tape in the composite cable is not uniform because of the influence of anisotropy. When the HTS composite cable is bent, its critical current is about 90% of the straight HTS composite cable. Therefore, the design method and the proposed experimental system are proved to be effective as well.

The Supplementary Design Method of HTS SMES System Considering Voltage Distribution Characteristic

The Supplementary Design Method of HTS SMES System Considering Voltage Distribution Characteristic

Design and Comparison of a 1-MW/5-s HTS SMES With Toroidal and Solenoidal Geometry

The design of a HTS SMES coil with solenoidal and toroidal geometry is carried out based on a commercially available 2G HTS conductor. A SMES system of practical interest (1 MW / 5 s) is considered. The comparison between ideal toroidal and solenoidal geometry is first discussed and the criteria used for choosing the geometrical parameters of the coils' bore are explained. The design of the real coil is then carried out and the final amount of conductor needed is compared. A preliminary comparison of the two coils in terms of AC loss during one charge discharge cycle is also discussed.

100 kJ/50 kW HTS SMES for Micro-Grid

A 150 kJ/50 kW conduction-cooled HTS SMES have been developed. This paper presents the design and configuration of the SMES and parts of important test results. The magnet of the SMES is a solenoid type coil made of Bi2223/Ag tapes, and cooled to about 20 K by conduction-cooled method. To evaluate the performance of the SMES, a series of tests are successfully carried out in an electric power system dynamic simulation laboratory. The current carrying ability of the magnet, the active and reactive power exchange capability between the SMES and power system, and the power compensating effect of the SMES are experimentally investigated and some test results are given. The designed SMES is key equipment for the micro-grid demonstration garden of Yunnan electric power grid of China, and will be installed for field tests.

Experimental demonstration and application planning of high temperature superconducting energy storage system for renewable power grids

Since high temperature superconducting magnetic energy storage system (HT SMES) has attracted significant attention for their fast response in milliseconds, high efficiency (cyclic efficiency over 95%) and unlimited times of charging and discharging cycles, it can be used for system stabilizing – damping out low frequency power oscillations. A voltage source converter (VSC) based HTS SMES has been optimal designed for achieving a high efficiency and has been constructed by China Electric Power Research Institute (CEPRI). This SMES can store the maximum energy, while for the first time used two states of art high temperature superconductors, YBCO and BSCCO tapes. It has been tested in a 110kV transmission power system by a dynamic power fluctuation compensation experiment using three different controlling strategies in CEPRI. The experimental output powers with these three strategies are compared and the results show that the SMES can trace the power variation and provide the required power to restrain the power fluctuation in milliseconds successfully. Finally, the application planning of SMES with the equivalent capacity in a practical renewable power system at Zhangbei wind power test base is evaluated by a case study based on the PSCAD/EMTDC simulation. An optimal switch time of the SMES in wind power system is presented using the real transmission parameters of Zhangbei power grid. This study can provide a reference for the demonstration of large-scale SMES systems in renewable power system.

An Effective Control Scheme of a Back-to-Back Converter with Shunt-Connected HTS SMES for Frequency Regulation of an Islanded Microgrid

High temperature superconducting magnetic energy storage (HTS SMES) is known as an effective solution to significantly decrease the voltage and power fluctuations of grid connected wind power generation system (WPGS). This paper implements an effective control scheme of a back-to- back converter with shunt-connected HTS SMES for the frequency regulation of an islanded microgrid. The back-to-back converter is used to connect the WPGS to the grid. A large-scale HTS SMES is linked to the DC side of the back-to-back converter through a two-quadrant DC/DC chopper. An adaptive control strategy is implemented for the back-to-back converter and the two-quadrant DC/DC chopper to improve the efficiency of the whole system. The performance of the proposed control system was evaluated in a test power system using PSCAD/EMTDC. The simulation results clearly show that the back-to-back converter with shunt-connected HTS SMES operates effectively with the proposed control strategy for stabilizing the power system frequency fluctuations.

Dynamic Thermal Characteristics of a Conduction-Cooled HTS SMES System

During operating, SMES system will suffer thermal load by AC losses and thermal disturbance which may cause unstable for HTS magnets. In this paper, dynamic thermal response of a conduction-cooled HTS SMES system in power exchanging and local heat disturbance condition is simulated to make comparison on cooling effect for different cooling configuration. 3-D SMES models based on heat conduction equation are established and solved with finite element methods. The results show the relationship between the cooling configuration and the transient stability of SMES system.

Analysis of Eddy Current Losses and Magnetization Losses in Toroidal Magnets for a 2.5 MJ HTS SMES

A SMES magnet can be operating in three different modes: charging, storing, and discharging. The eddy current losses and magnetization losses are generated during charging and discharging in the SMES system. The eddy current losses per cycle are generated mainly during discharging period because the discharging period is generally shorter that for charging. Magnetization losses per cycle are generated mainly during the charging. In this paper, we investigated a decrease in eddy current losses according to the shapes of conduction cooling plates. The cooling plate having small eddy current losses was designed by dividing and slitting. Also, the magnetization losses in the toroidal coil constructed with many pancake coils were analyzed using 3-D finite element method during the initial charging period and some discharging periods in an operating scenario for the 2.5 MJ SMES.

Power quality enhancement of renewable energy source power network using SMES system

This paper deals with power quality enhancement of renewable energy source power network using SMES system and describes the operation characteristics of HTS SMES system using real-toroidal-type SMES coil for smoothening the fluctuation of large-scale renewable energy source such as photovoltaic (PV) power generation system. It generates maximum power of PV array under various weather conditions. SMES unit charges and discharges the HTS coil to mitigate the fluctuation of PV system output power. The SMES unit is controlled according to the PV array output and the utility power quality conditions. The grid connected PV and SMES system has been modeled and simulated using power-hard-in-the-loop simulation (PHILS). The PHILS results demonstrated the effectiveness of the SMES system for enhancing power quality in power network including large-scale renewable energy source, especially PV power generation system.

The design and testing of a cooling system using mixed solid cryogen for a portablesuperconducting magnetic energy storage system

A cooling system that uses solid nitrogen (SN2) as an effective heat capacity enhancer wasrecently introduced to enhance the thermal stability of the HTS SMES. Since SN2 has alarge enthalpy with minimal weight, it enables a portable system by increasing therecooling to recooling time period (RRTP). However, contact between the SN2 and HTSSMES magnet can be broken by repeated thermal disturbances (thermal ‘dry-out’phenomena). Therefore, it is essential to improve thermal contact to allow full use of theheat capacity of SN2. This study evaluated the effect of using a mixture containing SN2and a small amount of a liquid cryogen as a cooling system in the HTS SMESsystem. The performance of the cooling system was evaluated using the mixedcryogen and compared with that of SN2 alone. In addition, the role of liquid neon(Ne) as a heat exchanger between SN2 and the HTS SMES magnet is discussed.

Quench detection system for twin coils HTS SMES

The quench detection and protection system is a critical element in superconducting magnets. After a short summary of the quench detection and protection issues in HTS magnets, an original detection system is presented. The main feature of this system is an active protection of the detection electronics during the discharges, making it possible to use standard electronics even if the discharge voltage is very high. The design of the detection system is therefore easier and it can be made very sensitive. An implementation example is presented for a twin coil HTS SMES prototype, showing the improvements when compared to classical detection systems during operation.

Operating Characteristic Analysis of HTS SMES for Frequency Stabilization of Dispersed Power Generation System

This paper analyses operating characteristic of high temperature superconducting magnetic energy storage (HTS SMES) for frequency stabilization of dispersed power generation system. The wind power generation system (WPGS) fluctuates due to wind speed variation and affects the frequency and voltage fluctuations of the utility. SMES is probably a key technology to overcome these fluctuations. To stabilize power system frequency, a large-scale HTS SMES is connected to the terminal of the WPGS. The authors analysed the load side frequencies using two different configurations of SMES, one consisting of a single magnet and the other of a dual magnet. From the simulation results, it can be concluded that the SMES is a useful device for stabilizing the power system frequency fluctuations, and a dual magnet type SMES is more effective for frequency stabilizing but exhibits more AC loss due to the increased operating current than a single magnet type.