High-temperature Superconducting Magnetic Energy Storage Research Articles

Longitudinal Insulation Design of Hybrid Toroidal Magnet for 10 MJ High-Temperature Superconducting Magnetic Energy Storage

Longitudinal Insulation Design of Hybrid Toroidal Magnet for 10 MJ High-Temperature Superconducting Magnetic Energy Storage

Mechanism Analysis and Experimental Validation of Employing Superconducting Magnetic Energy Storage to Enhance Power System Stability

This paper investigates the mechanism analysis and the experimental validation of employing superconducting magnetic energy storage (SMES) to enhance power system stability. The models of the SMES device and the single-machine infinite-bus (SMIB) system with SMES are deduced. Based on the model of the SMIB system with SMES, the action mechanism of SMES on a generator is analyzed. The analysis takes the impact of SMES location and the system operating point into consideration, as well. Based on the mechanism analysis, the P-controller and Q-controller are designed utilizing the phase compensation method to improve the damping of the SMIB system. The influence of factors, such as SMES location, transmission system reactance, the dynamic characteristics of SMES and the system operating point, on the damping improvement of SMES, is investigated through root locus analysis. The simulation results of the SMIB test system verify the analysis conclusions and controller design method. The laboratory results of the 150-kJ/100-kW high-temperature SMES (HT-SMES) device validate that the SMES device can effectively enhance the damping, as well as the transient stability of the power system.

Laboratory and Field Tests of Movable Conduction-Cooled High-Temperature SMES for Power System Stability Enhancement

This paper introduces the first movable conduction-cooled high-temperature superconducting magnetic energy storage (SMES) system developed in China. The SMES is rated at 380 V/35 kJ/7 kW, consisting of the high-temperature magnet confined in a Dewar, the cryogenic unit, the converter, the monitoring and control unit, the container, etc. The proposed SMES can be loaded onto a truck to move to a desired location and put into operation with easy connection. Laboratory and field tests have been carried out to investigate the operational characteristics and to demonstrate the SMES effectiveness on improvements of system voltage stability and on the oscillation damping. Test results indicate that the SMES system has the features of fast response and four-quadrant power operation. The accessories for the movability of the SMES system are well designed. The system is feasible to be used in power systems.

Power Compensation and Power Quality Improvement Based on Multiple-Channel Current Source Converter Fed HT SMES

The purpose of this paper is to propose the high-performance modulation strategy, power control and current regulation schemes for a multiple-channel current source converter (CSC) fed high temperature (HT) superconducting magnetic energy storage (SMES), which can in turn function as the frequency stabilizer and active power filter for the distributed generation system. The key is to design and implement the interleaved space vector modulation technique to suppress the switching harmonics, the dynamic capacitor voltage control to damp LC resonance as well as regulate grid currents accurately, and the DC current balancing strategy to avoid the circulating currents. The multiple-channel CSC fed HT SMES with the proposed control scheme is verified to provide good performance in power compensation and power quality improvement.

Nickel–zinc ferrite fabricated by sol–gel route and application in high-temperature superconducting magnetic energy storage for voltage sag solving

Ni–Zn ferrite nanoparticles of well controlled electromagnetic properties can be obtained through some chemical methods. In this study, the fine particles of Ni–Zn ferrite were prepared and fabricated using sol–gel route at low and high temperatures. The results gathered from the X-ray diffraction (XRD) indicated the amount of single-phase spinel ferrite constituents could be formed at a temperature below 400 °C. The Fourier transform-infrared spectroscopic (FT-IR) and the analyses using the microscopic photomicrographs were used to identify the formation of Ni–Zn spinel ferrite. The initial magnetic permeability showed that the inductance of the fabricated ferrite cores was of the highest value. Therefore, a laboratory coil equipped with a high-temperature superconducting magnetic energy storage (HT-SMES) was designed. The theoretical analysis of the torus with rectangular shaped coils was also carried out, and for this, a consideration for the average magnetic field inside the torus was used to calculate the inductance of the shape. Using uninterruptible power supply (UPS) and power conditioning system (PCS) which give details of the application of μ-SMES in solving voltage sag, a schematic diagram is also reported.

High temperature SMES for improving power system stabilities

Superconducting magnetic energy storage (SMES) system has been proven very effective to improve power system stabilities. It is realized with superconductivity technology, power electronics and control theory. In order to promote the application of such kind control device and to further investigate the properties of the controller, a detail mathematic model of such control device is developed. Based on the developed model, extensive analysis including time domain simulation is carried out to investigate the characteristic of the SMES to compensate the unbalanced dynamic active and reactive power of AC power system. The capability of SMES to increase power system transient and small signal perturbation stabilities are analyzed. A prototype SMES is developed, in which the conduction cooling and the high temperature superconductive techniques are used. The performance of the prototype is experimentally investigated in a laboratory environment. Very encouraging results are obtained. After a brief introduction of the SMES control system and the principle of its capability to improve power system stabilities, the details of the mathematic model, the theoretical analysis, the developed device and the experiment test results are all given in this paper.

Design of a 150 kJ high-Tc SMES (HSMES) for a 20 kVa uninterruptible power supply system

A High temperature Superconducting Magnetic Energy Storage (HSMES) system has been designed and is being built by ACCEL Instruments GmbH in cooperation with the German companies AEG SVS GmbH, and EUS GmbH, and the utility company E.ON Bayern AG. The magnet is designed for an energy of 150 kJ. The superconducting coil is composed of twenty double pancakes wound of a high temperature superconductor tape with BSCCO-2223 filaments. The coil and the shield are conduction-cooled using a cryocooler; the cryostat is free of cryogens. The current leads are composed of a resistive part and a high temperature superconducting BSCCO-2212 MCP element. The HSMES will be integrated in a 20 kVA uninterruptible power supply (UPS) system coupled to the electrical grid for enhancing the power quality of a selected grid user. The design of the HSMES UPS system is described. A test module composed of two double pancakes wound from pre-series superconductor tapes was manufactured and tested at 77 K in order to check the magnet design and the coil manufacturing technique.

Improved controller for power conditioner using high-temperature superconducting magnetic energy storage (HTS-SMES)

One of the most important functions in a superconducting magnetic energy storage (SMES) system when used for power conditioning, is the ability to charge the super-conducting coil as fast as possible to ensure that it is ready when it is next required. This paper describes a novel controller for a high-temperature SMES (HTS-SMES) that can ensure: 1) fast return of energy to the superconducting coil under constant-current mode and 2) a constant and sinusoidal input supply current irrespective of the varying load demand with and without harmonics. In the new HTS-SMES proposed, two hysteresis controllers are used, one to control the magnitude, phase and the waveform of the ac supply current, and the other is to control a dc chopper to regulate the SMES coil current. The first hysteresis controller ensures that as far as the power utility is concerned, the load appears to the utility system as a constant sinusoidal load with unity power factor irrespective whether the load is distorted or varying in nature. The second hysteresis controller has been designed to regulate the energy in and out of the superconducting coil. A special feature of this controller is its ability to smoothly charge the superconducting coil using constant current charging so that it can be ready for the next discharging operation as soon as possible. Analysis of the circuit operation under hysteresis control is presented in details. Simulation and experimental results are presented demonstrating the feasibility of the proposed power conditioning system.