Application of 100 kJ/50 kW high-temperature superconducting magnet energy storage system in micro-grid

超导磁储能系统（superconducting magnetic energy storage,SMES）能够实现与电网之间的快速功率交换,对于增强电网稳定性,改善电能质量具有重要意义。本文针对一套100 kJ/50 kW高温超导磁储能系统,对其超导磁体设计与低温系统,功率调节系统的拓扑及控制策略设计、主监控系统的设计分别进行了阐述和分析。为了验证整个磁储能系统的性能,进行了相关的开环功率调节实验。实验结果表明,整套系统运行良好,SMES能够快速的响应主监控系统发出的功率指令,实现SMES与电网之间快速的功率交换。基于上述对SMES的分析和实验测试,结合云电科技园微电网的拓扑,给出了几种SMES在微电网中应用的试验方案,以验证SMES在微电网中应用的性能和作用。     

Dynamics and stability of wind and diesel turbine generators withsuperconducting magnetic energy storage unit on an isolated power system

Dynamic system analysis is carried out on an isolated electric power system consisting of a diesel generator and a wind-turbine generator. The 150 kW wind turbine is operated in parallel with a diesel generator to serve an average load of 350 kW. A comprehensive digital computer model of the interconnected power system including the diesel and wind-power dynamics with a superconducting magnetic energy storage (SMES) unit is developed. Time-domain solutions are used to study the performance of the power system and control logic. Based on a linear model of the system, it is shown that changes in control-system settings could be made to improve damping and optimization of gain parameters and stability studies are done using the Lyapunov technique and eigenvalue analysis. The effect of introducing the SMES unit for improvement of stability and system dynamic response is studied     

超导储能系统提高风电场暂态稳定性研究

应用超导储能系统(SMES)对提高风电场的暂态稳定性进行了研究。在深入研究超导储能系统运行原理的基础上,建立了基于电压型换流器(VSC)的超导储能系统模型,实现了有功功率和无功功率的解耦控制,并提出了有功、无功功率综合控制策略。利用PSCAD/EMTDC软件进行了仿真计算,结果说明超导储能系统不但能够在风速波动时平滑风电场的功率输出,而且能够提高风电系统的暂态稳定性。     

Application of magnetic energy storage unit as load-frequencystabilizer

Fast-acting energy storage devices can effectively damp electromechanical oscillations in a power system because they provide storage capacity in addition to the kinetic energy of the generator rotor, which can share the sudden changes in power requirement. The effectiveness of small-sized magnetic energy storage (MES) units (both superconducting and normal loss types) for this application is shown, and means of best utilizing the small energy storage capacity of such units to improve the load-frequency dynamics of large power areas are suggested. The proposed method of improving the load frequency control of power systems has the advantage that it does not require the governor or any other part of the power system to perform any sophisticated control action. The control logic suggested for this purpose takes the area control error as its input and uses inductor current deviation feedback. In a power system with a SMES (superconducting MES) unit, the optimal setting of the integrator gain is altered to a higher value. With the suggested control measure, SMES units of 4-6 MJ capacity would suffice in reducing the maximum deviations of frequency and tie-line power flow by about 40% in power areas of 1000-2000 MW capacity     

高温超导磁储能装置功率调节特性实验研究

介绍了所研制的直接冷却式高温超导磁储能(SMES)系统,通过动模实验研究了具有电流源型逆变器SMES装置的功率调节特性,包括装置的储能、有功功率和无功功率调节过程和特性等。研究结果表明,该装置具有快速有效与系统交换功率的能力,可以在四象限内进行有功功率和无功功率独立调节,从而为实现电力系统动态不平衡功率补偿创造了条件。     

Development and simulation of systematic of Micro-SMES for operating at high-temperature regions

近年来第Ⅱ代YBCO高温超导涂层导体的制备工艺取得巨大的进展,其优越于第Ⅰ代BSCCO高温超导体的性能使它在电力领域的应用受到广泛重视.本文考虑到YBCO涂层导体磁场下各向异性载流特性,在确保储能容量的基础上最大限度地减少导体用量获得超导磁储能(SMES)磁体的优化;依据磁体损耗和引线漏热分析进行过冷液氮低温系统的整体设计;采用斩波器和电压型变换器实现SMES与系统间的能量/功率传递;通过仿真建模探索其在电力系统中的作用和影响,并对应用的可行性进行了探讨.     

Sampled data automatic generation control with superconductingmagnetic energy storage in power systems

A discrete state-space model of a two-area interconnected power system with reheat steam turbine, governor deadband nonlinearity and superconducting magnetic energy storage is developed in this paper. The effect of a small-capacity superconducting magnetic energy storage (SMES) system is studied in relation to supplying sudden power requirements of real power load. The feasibility of using an IGBT power converter instead of a thyristor converter as a power conditioning system with the SMES is studied. Time domain simulation results are also presented which show the improvement of transient response with SMES     

Design, performance, and cost characteristics of high temperaturesuperconducting magnetic energy storage

A conceptual design for superconducting magnetic energy storage (SMES) using oxide superconductors with higher critical temperature than metallic superconductors has been analyzed for design features, refrigeration requirements, and estimated costs of major components. The study covered the energy storage range from 2 to 200 MWh at power levels from 4 to 400 MW. A SMES that uses high temperature superconductors (HTS) and operates at high magnetic field (e.g. 10 T), can be more compact than a comparable, conventional low-temperature device at lower field. The refrigeration power required for a higher temperature unit (20 to 77 K) will be less by 60% to 90%. The improvement in energy efficiency is significant for small units, but less important for large ones. The material cost for HTS units is dominated by the cost of superconductor, so that the total cost of an HTS system will be comparable to a low temperature system only if the superconductor price in $/ampere-meter is made comparable by increasing current density or decreasing wire cost     

Application of superconducting magnetic energy storage in electrical power and energy systems: a review

Superconducting magnetic energy storage (SMES) is known to be an excellent high‐efficient energy storage device. This article is focussed on various potential applications of the SMES technology in electrical power and energy systems. SMES device founds various applications, such as in microgrids, plug‐in hybrid electrical vehicles, renewable energy sources that include wind energy and photovoltaic systems, low‐voltage direct current power system, medium‐voltage direct current and alternating current power systems, fuel cell technologies and battery energy storage systems. An extensive bibliography is presented on these applications of SMES. Also, some conclusive remarks in terms of future perspective are presented. Also, the present ongoing developments and constructions are also discussed. This study provides a basic guideline to investigate further technological development and new applications of SMES, and thus benefits the readers, researchers, engineers and academicians who deal with the research works in the area of SMES. Copyright © 2017 John Wiley & Sons, Ltd.     

光伏发电系统的超导储能设计

超导储能(SMES)具有非常快速的功率调节能力和灵活的四象限运行能力,可完成调节电力系统功率因数、补偿电压跌落等功能。文章针对光伏发电系统的特殊运行方式,提出了利用光伏出力与本地负荷需求的差值作为SMES控制器的功率控制信号策略。在PSCAD/EMTDC仿真平台建立了超导储能系统模型,并对其在光伏发电系统的中的运行控制方式进行研究。研究结果表明,超导储能与光伏系统配合可以很好地解决光伏发电功率易受环境影响、不可调节、难于满足负荷需求的问题,对由负荷变化引起的母线电压波动和故障引起的母线电压跌落具有良好的补偿作用。     

Stabilization and control of tie-line power flow of microgrid including wind generation by distributed energy storage

High penetration of wind generation in electrical microgrids causes fluctuations of tie-line power flow and significantly affects the power system operation. This can lead to severe problems, such as system frequency oscillations, and/or violations of power lines capability. With proper control, a distribution static synchronous compensator (DSTATCOM) integrated with superconducting magnetic energy storage (SMES) is able to significantly enhance the dynamic security of the power system. This paper proposes the use of a SMES system in combination with a DSTATCOM as effective distributed energy storage (DES) for stabilization and control of the tie-line power flow of microgrids incorporating wind generation. A new detailed model of the integrated DSTATCOM-SMES device is derived and a novel three-level control scheme is designed. The dynamic performance of the proposed control schemes is fully validated using MATLAB/Simulink.     

超导储能对并网型风电场运行性能影响的仿真分析

采用超导储能(SMES)可以改善风电场并网运行的稳定性,针对风电系统中出现的联络线短路故障和风电场的风速扰动,提出利用超导储能安装点的电压偏差信号作为超导储能有功控制器的控制策略。为了验证这种策略的有效性,建立了风电机组和超导储能装置的数学模型,并利用MATLAB/Simulink软件搭建了风电场接入电网后的仿真模型。仿真结果表明,采用该控制策略不仅可以在网络故障后有效地提高风电场的稳定性,而且能够在快速的风速扰动下平滑风电场的功率输出,降低风电场对电网的冲击。     

A new power-conditioning system for superconducting magnetic energystorage

A power conditioning system concept for superconducting magnetic energy storage (SMES), which can independently regulate the active and reactive power of the utility network, is presented. The system is composed of ten 100 MW modules connected in parallel. Each 100 MW module consists of a tap changing transformer and a 12 pulse, force commutated power converter. This system offers a significant reduction of the system rating by reducing the reactive power demand in the converter with control of the tap changing ratio and the converter firing angle. The operational concept of this system is verified through mathematical analysis and computer simulation. The dynamic system interaction between the SMES coil and the AC network is analyzed using a simulation model with EMTP. The analysis results prove that the concept is feasible. This system can be built with commercially available components and proven technologies     

高温超导体在小型超导储能装置中的应用

从高温超导体在小型超导储能 (MicroSuperconductingMagneticEnergyStorage SMES)装置中的两大应用 用作储能线圈和电流引线出发 ,介绍了一个工作在液氮温区的超导储能装置和低温超导储能装置的两种电流引线。     

Enhancement of transient stability of an industrial cogeneration system with superconducting magnetic energy storage unit

This paper has developed the coordination of load shedding scheme and superconducting magnetic energy storage (SMES) unit to enhance the transient stability of a large industry cogeneration facility. The load-shedding scheme and the tie line tripping strategy by using the frequency relays have been designed to prevent the power system from collapse when an external fault of utility power system occurs. An actual external fault case and a simulated internal fault case have been selected to verify the accuracy of the load shedding scheme by executing the transient stability analysis. To improve the frequency and voltage responses, an SMES unit with various control modes has been installed in the cogeneration system. The sensitivity analysis of the SMES unit with different parameters is applied to achieve better system responses. Besides, an SMES unit with active power deviation as feedback signal is also considered to improve the electric power fluctuation of the study plant with rolling mills. It is found that the SMES system will enhance the electric power quality and minimize the economic losses of the cogeneration facility due to unnecessary load shedding.     

Power quality improvement of a stand-alone power system subjected to various disturbances

In wind-diesel stand-alone power systems, the disturbances like random nature of wind power, turbulent wind, sudden changes in load demand and the wind park disconnection effect continuously the system voltage and frequency. The satisfactory operation of such a system is not an easy task and the control design has to take in to account all these subtleties. For maintaining the power quality, generally, a short-term energy storage device is used. In this paper, the performance of a wind-diesel system associated with a superconducting magnetic energy storage (SMES) system is studied. The effect of installing SMES at wind park bus/load bus, on the system performance is investigated. To control the exchange of real and reactive powers between the SMES unit and the wind-diesel system, a control strategy based on fuzzy logic is proposed. The dynamic models of the hybrid power system for most common scenarios are developed and the results presented.     

Enhancing the utilization of photovoltaic power generation bysuperconductive magnetic energy storage

The authors demonstrate that a superconductive magnetic energy storage (SMES) system can enhance large-scale utilization of photovoltaic (PV) generation. Results show that power output from a SMES system can be used to smooth out PV power fluctuations so that the combined PV/SMES output is dispatchable and free from fluctuations. Power generated from PV arrays is shown to be fully utilized under different weather conditions, and PV penetration is increased to significant levels without adversely affecting the power system. Coupled with PV generation, a SMES system is even more effective in performing diurnal load leveling. A coordinated PV/SMES operation scheme is proposed, and its demonstration under different weather conditions is discussed     

Experimental evaluation of nonlinear robust control for SMES to improve the transient stability of power systems

This paper presents a new approach and corresponding experiments for the nonlinear robust control of a superconducting magnetic energy storage (SMES) unit to improve the transient stability of power systems. Based on the result of SMES prototype experience, a new dynamic model with disturbances of SMES is adopted, and transferred to the per unit system for simplifying the dynamic analysis and controller design. Then, feedback linearization scheme and linear H/sub /spl infin// control theory are applied to design a novel SMES nonlinear robust controller in a one-machine infinite bus (OMIB) power system. In order to confirm such positive effects of the proposed control strategy, experiments are carried on a laboratory setup of SMES comparing that with a conventional proportional-integral (PI) controller. The results of the experiments demonstrate that the proposed nonlinear robust controller has more excellent performance to improve the transient stability of power systems than that of conventional PI controllers.     

Direct current control strategy of SMES current source converter--Design and simulation

主要研究超导磁储能系统(SMES)用电流型变流器的控制策略.首先为了简化传统三逻辑PWM控制的结构,改进了电流型变流器的主电路拓扑.在此基础上,提出了基于比例谐振微分(PRD)控制的直接电流控制策略.PRD控制既可实现对交流量控制的零稳态误差,又可增大系统阻尼,降低输出的超调量和调节时间,提高系统的响应速度,进而控制SMES与电网之间的实时功率交换.理论分析及MATLAB仿真结果验证了所提出的PRD控制策略具有良好的动态和稳态性能.     

Power flow control and damping enhancement of a large wind farm using a superconducting magnetic energy storage unit

A novel scheme using a superconducting magnetic energy storage (SMES) unit to perform both power flow control and damping enhancement of a large wind farm (WF) feeding to a utility grid is presented. The studied WF consisting of forty 2 MW wind induction generators (IGs) is simulated by an equivalent 80 MW IG. A damping controller of the SMES unit is designed based on the modal control theory to contribute proper damping characteristics to the studied WF under different wind speeds. A frequency-domain approach based on a linearised system model using eigen techniques and a time-domain scheme based on a nonlinear system model subject to disturbance conditions are both employed to validate the effectiveness of the proposed SMES unit with the designed SMES damping controller. It can be concluded from the simulated results that the proposed SMES unit combined with the designed damping controller is very effective in stabilising the studied large WF under various wind speeds. The inherent fluctuations of the injected active power of the WF to the power grid can also be effectively controlled by the proposed control scheme.