Application of a modified flux-coupling type superconducting fault current limiter to transient performance enhancement of micro-grid

Yang

et al. 2017

Energies

Self Cite

Abstract:In regard to the rapid development of renewable energy sources, more and more photovoltaic (PV) generation systems have been connected to main power networks, and it is critical to enhance their transient performance under short-circuit faults conditions. This paper proposes and studies the coordinated control of a flux-coupling-type superconducting fault current limiter (SFCL) and a superconducting magnetic energy storage (SMES), to improve the fault ride through (FRT) capability and smooth the power fluctuation of a grid-connected PV generation system. Theoretical analyses of the device structure, operating principle and control strategy are conducted, and a detailed simulation model of 100 kW class PV generation system is built in MATLAB/SIMULINK. During the simulations of the symmetrical and asymmetrical faults, the maximum power point tracking (MPPT) control is disabled, and four different cases including without auxiliary, with SFCL, with SMES, and with SFCL-SMES, are compared. From the demonstrated results, the combination of without MPPT and with SFCL-SMES can more efficiently improve the point of common coupling (PCC) voltage sag, inhibit the DC-link overvoltage and alleviate the power fluctuation. Finally, a preliminary parameter optimization method is suggested for the SFCL and the SMES, and it is helpful to promote their future application in the real PV projects.

Section: Theoretical Presentation Of a Grid-connected Photovoltaic Gementioning

confidence: 99%

Section: Modeling and Parametersmentioning

confidence: 99%

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Coordinated Control of Superconducting Fault Current Limiter and Superconducting Magnetic Energy Storage for Transient Performance Enhancement of Grid-Connected Photovoltaic Generation System

Yang

et al. 2017

Energies

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“…In [21,22], the positioning of resistive-type SFCLs in direct-current (DC) and alternating-current (AC) micro-grids has been preliminarily discussed, and the simulation results imply that the SFCLs should be located in the direct path of current flowing from the DG units and the main network. In [23,24], the cooperative control of SFCL and an energy storage device is suggested to improve the robustness of a micro-grid against short-circuit faults, and the results are able to show the effectiveness of the proposed approach.…”

Section: Introductionmentioning

confidence: 98%

Technical Evaluation of Superconducting Fault Current Limiters Used in a Micro-Grid by Considering the Fault Characteristics of Distributed Generation, Energy Storage and Power Loads

et al. 2016

Energies

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Abstract:Concerning the development of a micro-grid integrated with multiple intermittent renewable energy resources, one of the main issues is related to the improvement of its robustness against short-circuit faults. In a sense, the superconducting fault current limiter (SFCL) can be regarded as a feasible approach to enhance the transient performance of a micro-grid under fault conditions. In this paper, the fault transient analysis of a micro-grid, including distributed generation, energy storage and power loads, is conducted, and regarding the application of one or more flux-coupling-type SFCLs in the micro-grid, an integrated technical evaluation method considering current-limiting performance, bus voltage stability and device cost is proposed. In order to assess the performance of the SFCLs and verify the effectiveness of the evaluation method, different fault cases of a 10-kV micro-grid with photovoltaic (PV), wind generator and energy storage are simulated in the MATLAB software. The results show that, the efficient use of the SFCLs for the micro-grid can contribute to reducing the fault current, improving the voltage sags and suppressing the frequency fluctuations. Moreover, there will be a compromise design to fully take advantage of the SFCL parameters, and thus, the transient performance of the micro-grid can be guaranteed.

“…Our research group has suggested a modified flux-coupling-type SFCL, which is a resistive-inductive type (hybrid type) SFCL, and is able to theoretically enhance the transient performance of an electrical system more efficiently (Chen et al 2015c, d; Deng et al 2015). This flux-coupling-type SFCL is to suppress the short-circuit current by controlling the magnetic path through a high-speed switch.…”

Section: Introductionmentioning

confidence: 99%

Conceptual design of a high-speed electromagnetic switch for a modified flux-coupling-type SFCL and its application in renewable energy system

Yang

et al. 2016

SpringerPlus

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The modified flux-coupling-type superconducting fault current (SFCL) is a high-efficient electrical auxiliary device, whose basic function is to suppress the short-circuit current by controlling the magnetic path through a high-speed switch. In this paper, the high-speed switch is based on electromagnetic repulsion mechanism, and its conceptual design is carried out to promote the application of the modified SFCL. Regarding that the switch which is consisting of a mobile copper disc, two fixed opening and closing coils, the computational method for the electromagnetic force is discussed, and also the dynamic mathematical model including circuit equation, magnetic field equation as well as mechanical motion equation is theoretically deduced. According to the mathematical modeling and calculation of characteristic parameters, a feasible design scheme is presented, and the high-speed switch’s response time can be less than 0.5 ms. For that the modified SFCL is equipped with this high-speed switch, the SFCL’s application in a 10 kV micro-grid system with multiple renewable energy sources are assessed in the MATLAB software. The simulations are well able to affirm the SFCL’s performance behaviors.