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The resistive-type superconducting fault current limiter (R-SFCL) is simple in configuration, near zero impedance at normal state, and can be quickly triggered by the fault current. So, it is a possible solution to suppress the fault current in the power grid. In this paper, the design and development of a 220-kV R-SFCL were reported. The core component of it is a module constructed by 128 bifilar coils. The bifilar coils are connected in series and parallel to form the module according to the application requirements. The bifilar coils are made of 12-mm-wide steel-stabilized 2G tapes, while 16 bifilar coils are connected in parallel to form a sub-module and 8 sub-modules are connected in series to form the module. For this fault current limiter, 10.75-km 2G tapes are used in total, and the resistance of the R-SFCL module is 4.5 Ω at 300 K. Besides, the half-size sub-module and the cryogenic insulation support (CIS) are developed and tested. [ABSTRACT FROM AUTHOR]

With increasing demand of the power load and the development of the new energy resources, voltage-sourced converter-based high-voltage direct current (VSC-HVDC) transmission system has been widely utilized. However, its development is seriously limited due to short circuit. To address this, high-temperature superconducting direct current fault current limiter (DC-SFCL) is designed. In this paper, a novel topology of DC-SFCL is firstly presented along with its principle and mathematical model. Secondly, the thermoelectric model of its superconducting current-limiting unit (SCLU) is established. In addition, simulation of VSC-HVDC system containing this novel DC-SFCL topology is analyzed using Simulink software. Finally, experimental measurements are designed and conducted to verify the correctness of the theoretical model. [ABSTRACT FROM AUTHOR]

The resistivetype superconducting fault current limiter (R-SFCL) is simple in structure, near zero impedance at normal state and can be quickly triggered by the fault current. Thus, it is a possible solution to limit the fault current in the power grid. In this paper, we report the fabrication and test for an R-SFCL module The R-SFCL module consists of seven bifilar coils connected in parallel, which were wound with two parallel 2G tapes. A 5mm spacer was co-wound between adjacent turns to act as the highvoltage insulation. In the tests, we test the current distribution among the bifilar coils, and then simulated short-circuit tests were conducted on the module to obtain its performance under fault current surge. [ABSTRACT FROM AUTHOR]

In the applications of high-temperature superconductors (HTS), the HTS tapes are usually exposed to the external magnetic field with different orientations. The critical current and AC loss are affected by both the field amplitude and field angles due to the anisotropy of HTS tapes. In this work, we first introduce the experimental system to measure the magnetization loss in HTS tapes based on the calibration-free method. Then, we present the magnetization loss results in 4.8-mm-wide AMSC wire, 4-mm-wide SuperPower wire, 4-mm-wide SuNam wire, and 10-mm-wide Fujikura wire in a perpendicular applied field at 77 K. The field amplitude is up to 100 mT, and the frequency varies from 44.2 to 87.1 Hz. We also present the magnetization loss in AMSC wire, SuperPower wire, SuNam wire, and Fujikura wire at different field angles. The field angle varies from 10 to 90 ∘ in 10 ∘ steps. The loss reduction with the decreasing of the field angle shows the anisotropic property of HTS tapes. We finally plot the measured magnetization loss of the samples as a function of the magnetic field amplitude normalized by the field angle to verify an empirical formula. [ABSTRACT FROM AUTHOR]

Overcurrent performance of high-temperature superconducting (HTS) coated conductor (CC) is one of the most crucial parameters for industrial applications, especially in superconducting fault current limiters (SFCLs). Thus, numerical study of overcurrent process becomes desirable in design of these superconducting devices. In this paper, a field-circuit combined model is introduced to study the overcurrent process of HTS CCs. This model is built by both MATLAB and COMSOL. Circuit parameters, electromagnetic, and temperature distributions are individually calculated by different software. Temperature ( T), magnetic intensity ( B), and generated heat ( Q) are used as real-time intermediate exchanging variables. Accuracy of this model is verified by short-fault experiments on straight HTS CC. Further applications, such as reclosing process and superconducting coils are both performed. Results obtained in this paper prove the validity of this model; this model can be helpful in future design of superconducting devices. [ABSTRACT FROM AUTHOR]

The global consumption of electricity is on the rise due to the industrial and population growth. The number of power generation and distribution facilities is increasing in order to meet the growing demand. Furthermore, the low impedance of power systems is causing a fault current that exceeds the capacity of the existing circuit breaker. In this paper, a method was suggested which limits the initial fault current by combining a superconducting fault current limiter (SFCL) with the existing flux-offset-type fault current limiter (FCL). Results showed that the initial fault current within a half cycle was limited by approximately 60%, while the fault current after a half cycle was limited by approximately 80 %. Overall, 99.8% of the fault current was limited, while the power burden on the SFCL was reduced by more than 50%. [ABSTRACT FROM AUTHOR]

Optimization of high-temperature superconductor (HTS) coated conductor for standalone superconductor fault current limiting (FCL) systems and for inherently fault current limiting cables is quite different. To minimize the amount of conductor, and so to lower cost, a high conductor critical current per unit width I is desirable to minimize the number of parallel conductors required to meet operating current requirements. In standalone systems, a high normal state resistivity and thin conductor are also desirable to minimize conductor length. But in FCL cables, conductor length is fixed by the application. Limits on I , resistivity, and thickness also come from the necessity to prevent local overheating during a fault or, in a cable, bubbling of liquid nitrogen which could precipitate a dielectric failure. A critical insight is that even for low-voltage faults, hot spots can arise in the conductor, and heating within these hot spots must also be controlled. A simple model is introduced to describe this phenomenon and estimate hot-spot heating. Tolerable hot-spot temperature rise in FCL cables is drastically less than in standalone FCLs. Implications for design of FCL cables are discussed and their viability for applications such as linking substations at the distribution level is demonstrated. [ABSTRACT FROM AUTHOR]

This study has assessed the performance of a resistive superconducting fault current limiter based on polycrystalline SmBaCuO (Sm-123) subjected to 750 short-circuit events with acting time 80 ms. Preliminary results indicate that polycrystalline Sm-123 cuprates can be used to build superconducting fault current limiters. The results of this study have demonstrated that after 616 short-circuit repetitions, the superconducting element was able to limit the fault current without degradation on low-level fault current density J < 3.7 kA/cm. [ABSTRACT FROM AUTHOR]

High-temperature superconducting (HTS) tapes currently used for the manufacture of resistive fault current limiters use metallic substrates upon which the HTS film is grown. Because the alloys used for these substrates, such as Hastelloy, have a rather high resistivity and low thermal conductivity, the HTS film must be protected by a more conducting metallic layer acting as a shunt to avoid burn out during a fault. This shunt layer limits severely the electric field generated during the fault to values smaller than 100 V/m. A long length of tape is then necessary to achieve the desired high voltage. We show here that by using a high thermal diffusivity dielectric substrate such as sapphire, it is possible to obtain much higher electric fields of up to several kilovolts per meter. [ABSTRACT FROM AUTHOR]

The saturated cores Fault Current Limiter (FCL) is one of the leading candidates for providing a commercial robust solution to the fault current problem. Basically, the saturated cores FCL offers low impedance during normal grid operation due to its saturated cores state and high impedance in fault events due to cores desaturation. We developed a method to obtain the nonlinear inductance curve L( I) of the saturated cores FCL from which we show that the dynamic inductance component, dL/ dt, contributes significantly to the FCL limiting capabilities. Specifically, we show that in some parts of the AC cycle, the dynamic inductance term dominates over the static inductance in contributing to the voltage drop across the device. We conclude that the design of saturated cores FCL should consider the dynamic inductance and calculate its contribution to the FCL voltage to benefit from better device performances. [ABSTRACT FROM AUTHOR]

In this paper, a flux offset-type fault current limiter was proposed as a new means of reducing fault currents. The flux offset-type fault current limiter is a device that is integrated into the fault current technology, to which the flux offset principle of a transformer is applied, and is combined with a transformer and a fast switch. To secure the operation reliability of a flux offset-type fault current limiter, a simulation system was constructed to analyze its operation characteristics by generating a single line-to-ground fault and a triple line-to-line fault. According to the test results, the system performed stably without any impedance, because the primary and secondary winding fluxes of the transformer offset each other at normal times. However, when a fault current event occurred, because the fast switch was activated to limit the fault current by opening the secondary windings of the transfer within an average of 9.5 ms, which is shorter than the operation time of the existing electric circuit breakers by 3-5 cycles, the system is likely to perform protective coordination with circuit breakers in the future. In addition, the application of this current limiter could keep the fault current limit ratio to about 96 %. [ABSTRACT FROM AUTHOR]

There are many irreplaceable advantages of high temperature superconducting (HTS) fault current limiter, applying in electric utilities. It is expected to be able to solve excessive fault current problems and to enhance safety and stability of power systems. In this paper, the R and D of an improved bridge-type 10.5 kV three-phase superconducting fault current limiter (SFCL) was present. Each phase adopted a HTS coil with inductance of 6.2 mH. The three coils wound with 8,571 m Bi2223/Ag tapes totally. After installation at a 110 kV/10.5 kV substation in Hunan Province of China, the performances of the whole SFCL were tested, including a three-phase-to-ground short circuit experiment at the pre-setup short circuit point. And then, the SFCL was put into operations in the 10.5 kV power grids for more than 11000 h. About 3 years later, the SFCL was moved, reinstalled, and put into operation again since February 16 of 2011 at a 10.5-kV superconducting power substation located in Baiyin, Gansu Province of China. In this paper, the redesigned and manufactured cryostats with nonmagnetic stainless steel, tests, and long-term operations of the SFCL in 10.5 kV power grids were also described in detail. [ABSTRACT FROM AUTHOR]

A multi-physics finite element model of high-temperature superconductors (HTS) will be presented in this article. The electrical-thermal model is mainly based on Maxwell's equation and basic heat transfer equation to calculate the temperature propagation along the length of the superconducting tapes. According to the calculated temperature profile during quench, the surface thermal stress of the tape is obtained by a structural model. This model can be used to evaluate the degradation of tape performance due to the surface thermal stress, and the results can be used to minimize these effects in the SFCL system. The proposed model is used to investigate the uneven tape, the thickness of the copper layer and YBCO layer which is non-uniform. Methods of smoothing the degradation effect by adding auxiliary fixed points to the tape and changing the basic thickness of copper layer are discussed. [ABSTRACT FROM AUTHOR]

In a resistive superconducting fault current limiter (SFCL), the electrodynamic force among the YBCO tapes is enormous when experiencing a high short circuit current, which may cause deformation of tapes and damage of their electrical characteristics. The purpose of this paper is to investigate how much electrodynamic force the YBCO tapes can bear. In this paper, an electrodynamic force simulation model is built to simulate the force, which the two parallel tapes experience and their deformation when short-circuit currents of different value flow through. Then we conducted experiments to observe the deformation of the tapes when they are experiencing a short-circuit current and see if the volt-ampere characteristic of the tapes has a noticeable change after that. Combining the results of the simulation and the experiments, we can obtain the electrodynamic force that tapes can bear. The result can guide us to design the layout of the tapes in the SFCL in accordance with the required fault current level. [ABSTRACT FROM AUTHOR]

Superconducting fault current limiter (SFCL) has become one of the most ideal current limiting devices to solve the problem of increasing short-circuit current in high-voltage power grid. This paper presents a resistive-type SFCL model developed using simulation software PSCAD/EMTDC. After being verified by finite-element model and experimental results, the model is used to study the impact of SFCLs on the power grid and the co-ordination between SFCL and relay protections in 10 kV distribution network. A series of simulations are carried out to find appropriate parameters of SFCL model to cooperate with relay protection devices. The final result in this paper could provide important quantitative basis of parameters for SFCL to be applied in a real power system. [ABSTRACT FROM AUTHOR]

The original version of this article contains the following mistakes: On the second page 1st paragraph under heading “The Role of the Substrate Diffusivity” second and third sentences, 90 K, 300 cm2/s and 5 mm, should be replaced with 65 K, 100 cm2/s and 3 mm. [ABSTRACT FROM AUTHOR]