Energy storage systems provide viable solutions for improving efficiency and power quality as well as reliability issues in dc/ac power systems including power grid with considerable penetrations of ...renewable energy. The storage systems are also essential for aircraft powertrains, shipboard power systems, electric vehicles, and hybrid electric vehicles to meet the peak load economically and improve the system's reliability and efficiency. Significant development and research efforts have recently been made in high-power storage technologies such as supercapacitors, superconducting magnetic energy storage (SMES), and flywheels. These devices have a very high-power density and fast response time and are suitable for applications with rapid charge and discharge requirements. In this paper, the latest technological developments of these devices as well as advancements in the lithium-ion battery, the most power dense commercially available battery, are presented. Also, a comparative analysis of these high-power storage technologies in terms of power, energy, cost, life, and performance is carried out. This paper also presents the applications, advantages, and limitations of these technologies in a power grid and transportation system as well as critical and pulse loads.
The shortage of dc protection device limits the development of dc grids. This letter proposes a novel superconducting magnetic energy storage (SMES)-based transformerless series voltage restorer ...(TLSVR) for dc-load protections. The proposed SMES-TLSVR is made up mainly of a bidirectional-switch-based converter and a superconducting coil, and is interfaced in the series with the dc transmission line. It has the advantages of duplex voltage compensation ability, transformerless structure, and swift compensation response, and has a wider compensation range than traditional voltage-fed transformerless dynamic voltage restorer. The topology, circuit principle, and control strategy are elaborated in this letter. Finally, a kW-class SMES prototype is carried out to verify the feasibility of the proposed SMES-TLSVR.
Performance evaluations of a MW-class dynamic voltage restorer (DVR) system are presented for mitigation of voltage quality disturbances. A presag compensation strategy is introduced to lock the ...instantaneous magnitudes and phase angles of real-time line voltages, and thus to compensate the improper voltage components exactly after symmetrical or asymmetrical voltage disturbances. A 0.3-H/1.76-kA superconducting magnetic energy storage (SMES) magnet is used to cooperate with conventional battery energy storage (BES) device for developing a high-performance hybrid energy storage (HES) system. In the SMES-BES HES-based DVR system, the SMES can compensate the worst voltage sag for five cycles (1 MW, 100 ms, and absorb the highest voltage swell for six cycles (1 MW, 120 ms). The accessorial high-capacity BES device is subsequently discharged or charged for lasting long-time mitigation operations. Various simulation cases with regard to combined voltage sag, swell, and harmonic disturbances are carried out. The simulations and comparisons among the SMES-based, BES-based, and HES-based DVR schemes have demonstrated that the HES-based DVR scheme integrates the merits of fast response speed and high-power density from the SMES-based scheme, and the merits of low capital cost and high-energy density from the BES-based scheme.
With the recent advances in the field of applications which require a certain power level over a short period of timeand with the air-quality constraints which have become more stringent in the last ...few decades, the energy storagesystems (ESSs) have come to play a crucial role for the electric grid. Various aspects such as the historical evolutionof ESSs, technical characteristics, and applications for the ESSs are thoroughly addressed. Special emphasis is given tothe interaction between the smart grid (SG) and microcrogrids applications, on the one hand, and the ESSs, on the otherhand. Thus, the main goal of this work is to present the specialist and nonspecialist review of the most important ESSscurrently available on the market.
A hybrid toroidal magnet using MgB 2 and YBCO material is proposed for the 10 MJ high-temperature superconducting magnetic energy storage (HTS-SMES) system. However, the HTS-SMES magnet is ...susceptible to transient overvoltages caused by switching operations or lightning impulses, which pose a serious threat to longitudinal insulation. Accurate and efficient simulation of the voltage distribution characteristics of HTS- SMES magnets under transient overvoltages is important for the design of the longitudinal insulation of the magnets. Conventional modeling and analysis methods based on one turn conductor are not directly applicable to large-capacity HTS-SMES, due to the massive scale of the circuit model and requiring significant computational costs. In this paper, a "Two-Step" lumped parametric equivalent circuit model is proposed for large magnets to simplify the calculation. Then, the transient voltage distribution characteristics of the hybrid toroidal magnet for 10MJ HTS-SMES under lightning voltage impulse are analyzed. And the effect of the turn-to-turn insulation thickness on the voltage distribution characteristics is studied. Finally, a preliminary design of the longitudinal insulation of the hybrid toroidal magnet for 10 MJ HTS-SMES is presented. The proposed simulation model was verified by sample coils, which is consistent with the simulation results.
Morden railway transportation usually requires high-quality power supplies to guarantee fast and safe operation. Renewable energy such as solar power and wind power, will be highly utilized in future ...transportation systems. However, renewable energy technologies have issues of instability and intermittence. An energy compensation scheme with superconducting magnetic energy storage (SMES) is introduced for solving these energy issues of railway transportation. A system model consisting of the 1.5 kV/1 kA traction power supply system and the 200 kJ SMES compensation circuit were established using MATLAB/Simulink. The case study showed that if a 50 ms voltage fluctuating fault was from 1.2 kV to 1.8 kV in a traction system, the SMES could rapidly response within 5 ms and stabilize the voltage at 1.5 kV. Overall, the proposed new SMES scheme can potentially achieve the voltage stabilization and energy compensation for urban railway transportation.
We have been developing no-insulation (NI) REBCO coil system for its application in superconducting magnetic energy storage (SMES). SMES has the advantages of high efficiency, long life, and the ...ability to respond to large amounts of power instantaneously. However, SMES has an extremely low energy storage density. To address this issue, the use of NI-REBCO coils, designed to achieve both high thermal stability and high current density, is expected to enable the realization of high storage density in SMES. In addition, since SMES is a power device, high current and low inductance design is desired. Therefore, we focused on the use of a REBCO coil system composed of four pancake coils wound by assembling four electrically uninsulated REBCO tapes (strands) into a laminated bundle conductor (hereinafter referred to as bundle NI coils). However, within bundle NI coils, the inductance of each strand varies, leading to un-equal current sharing and intricate current distribution. In this study, we developed a numerical simulation program to elucidate the behavior of current change in the bundle NI coils assuming SMES operations, and the program was used for analytical evaluation of current distribution in bundle NI coils.
As the output power of wind farm is fluctuating, it is one of the important ways to improve the schedule ability of wind power generation to predict the output power of wind farm. The operation mode ...of tracking planned output takes the planned value issued by the grid dispatching as the control basis of wind power generation. This operation mode is easy to control, which not only meets the needs of power grid dispatching, but also improves the reliability and controllability of new energy generation. This paper introduces the traditional PI control strategy of SMES and combines the advantages of SMES and the characteristics of application scenarios, and introduces sliding mode variable structure control into SMES. Through simulation and comparison of two different control modes, it is verified that SMES adopting sliding mode variable structure control have the advantages of fast response speed and strong robustness, which can make the wind farm output stable power according to the planned value.
Conceptual design and performance evaluation of a voltage sag compensation scheme based on the superconducting fault current limiter (SFCL) and a MW-class dynamic voltage restorer (DVR) system ...integrated with superconducting magnetic energy storage (SMES) are presented and investigated. A pre-sag compensation strategy is introduced to lock the instantaneous magnitudes and phase angles of real-time line voltages for compensating the improper voltage components completely. A 0.3-H/1.76-kA SMES magnet is structurally designed for MW-class power exchange operations, and the SFCL's resistance is also estimated in detail. Various simulation cases with regard to voltage sag are carried out. The simulations have demonstrated that the proposed voltage sag compensation scheme is able to maintain the stabilizations of root-mean-square voltages, and mitigate the adverse effects of voltage sag on sensitive load. Furthermore, the compensated power injected to sensitive load by DVR is decreased owing to the additional voltage improvement provided by SFCL, thereby reducing the total capital costs of DVR.
The electrification of transport has been no exception for waterborne vessels. The reduction of emissions, especially during port maneuvering and operation, has accelerated the transition from fossil ...fuel to electric propulsion. Moreover, military vessels, with specialized electric weapon systems, or civil vessels, like offshore wind tug boats, have high power systems that additionally contribute to a higher electrification of the ship grid. Energy storage systems are essential to meet the power load economically and to improve the system`s reliability and efficiency. Therefore, the use of high energy density storage systems, as chemical batteries, or hydrogen fuel cells, has experienced a significant increase in demand. However, during high frequency load fluctuations, high energy density storage systems are not capable to actuate, since the discharge rate of these systems is physically limited, which may provoke: deterioration and reduction of the lifetime of the storage systems, voltage and frequency fluctuation of the ship grid. To overcome this limitation, this paper studies the use of a Superconducting Magnetic Energy Storage (SMES) as a supporting energy storage device for the ship grid. The guidelines for dimensioning, in power and energy, the SMES are stablished. Furthermore, an optimization method is developed in order to compare different superconducting materials, and operating temperatures.
