The application of superconducting fault current limiters (SCFCLs) in power systems is very attractive because SCFCLs offer superior technical performance in comparison to conventional devices to limit fault currents. Negligible impedance at normal conditions, fast and effective current limitation within the first current rise and repetitive operation with fast and automatic recovery are the main attributes for SCFCLs. In recent years there has been a significant progress in the research and development (R&D) of SCFCLs. This paper gives an extended review of different SCFCL concepts, SCFCL applications and the R&D status. Within the first part of this paper the most important SCFCLS and, to a limited extent, non-superconducting fault current limiter (FCL) concepts are explained and compared. The second part reviews interesting SCFCL applications at the distribution and transmission voltage level and the third part shows in detail the R&D status. It can be summarized that SCFCLs are, at present, not commercially available but several successful field tests demonstrated the technical feasibility of SCFCLs. First distribution level applications are expected soon. Considerable economical and technical benefits can be achieved by applying SCFCLs at the distribution and transmission voltage level.

https://iopscience.iop.org/article/10.1088/0953-2048/20/3/R01/pdf

High-temperature superconductor fault current limiters: concepts, applications, and development status

An inductive superconducting fault current limiter has been built and tested. It mainly consists of a copper coil, a superconducting tube, and an iron core which are concentrically arranged. The device is essentially a transformer with the secondary winding being the tube. The tube has diameter of 20 cm, a height of 35 cm, and is made of Bi2212 ceramic, fabricated by partial melting. The ceramic has the voltage current characteristic V-I/sup /spl alpha// with /spl alpha//spl ap/5. The critical current density defined by the 1 /spl mu/V/em criterion is about 1400 A/cm/sup 2/. Depending on the number of turns of the coil, the nominal current of the device was between 130 A and 250 A. In short circuit tests in a 480 V circuit, the prospective fault current of 8 kA was limited to about 5 times the nominal current. The test results are in good agreement with detailed simulations of both the normal operation (e.g. impedance, AC-losses) and the behaviour under fault conditions (i.e. evolution of the current). >

Tests of 100 kW High-T/sub c/ superconducting fault current limiter

We have been carrying out a saturable iron core reactive type superconducting fault current limiter (SFCL) development program since 2002. The major two disadvantages that people used to be foretold for a saturable iron core reactive type SFCL are the massive use of iron (resulting in large size, heavy weight, and high cost) and the high induced voltage hazard to the dc superconducting coil (this may damage the current supply of the dc bias) as a fault takes place. We have found the ways to deal with these two problems, making such kind of equipment reliable and cost effective. In this paper, we will report the technical data and testing results of a 3 phase lab testing model. Some key design parameters of the 35 kV/100 MVA prototype will also be presented.

Development of Saturated Iron Core HTS Fault Current Limiters

The present paper proposes a new the fault current limiter (FCL), which consists of a high T/sub c/ superconducting (HTS) element, three coils wound on the same core, and a magnetic field coil covering the HTS element. In this FCL, the initial limiting current level can be controlled by adjusting the inductances of the coils. Furthermore, an external AC magnetic field is applied to the HTS element to get higher resistance in the current-limiting phase. A current-limiting experiment by a model FCL was carried out, and the limiting performance of the FCL was observed. Both the initial limiting current level and the limiting impedance could be increased in this FCL compared with the corresponding values of the HTS element itself.

Development of flux-lock-type fault current limiter with high-T/sub c/ superconducting element

The application of a superconductor to a fault current limiter in a power system has been researched. The authors developed a magnetic shielding type superconducting fault current limiter using a Bi2212 thick film cylinder. This limiter consists of a primary winding on a superconducting cylinder for generating an AC magnetic field, the cylinder for shielding the field, an iron core for magnetic members and a control ring for controlling fault currents. When a fault occurs, the superconductive cylinder quenches and a magnetic circuit is formed inside the cylinder. As a result, the limiter has a high impedance to limit the fault current. The present study shows the limiting and recovery characteristics of the fault current limiter. >

A magnetic shielding type superconducting fault current limiter using a Bi2212 thick film cylinder

The authors investigate the design feasibility of an inductive iron core superconducting fault current limiter. A simplified thermo-electromagnetic analysis of the operating behavior of the fault current limiter is presented. This design is based on a high temperature superconducting shield surrounding a magnetic circuit with a primary winding generating an AC magnetic field. During fault conditions the field penetrates the core resulting in a large impedance, and thus a limitation of the fault current. In the analysis of this design, for voltages and currents up to 25 kV root-mean-square (RMS) and 2000 A RMS, it is shown that recuperation times for superconductors operating at liquid nitrogen temperatures are acceptable. >

http://ieeexplore.ieee.org/iel4/77/6032/00233770.pdf

Design considerations for an inductive high T/sub c/ superconducting fault current limiter

Several laboratory scale screened iron core superconducting fault current limiters (<1 kVA nominal rating) have been built and tested in order to study their fault current limitation characteristics. In this article the authors present the experimental results for a static impedance test and for a dynamic short circuit test. The static test is used to define the device operating conditions and the dynamic short circuit test is used to characterize the limiter`s performance. With the superconducting limiter in the test circuit, short circuit fault currents are limited to a few times the nominal current. The device impedance shows an initial rapid response followed by a more gradual increase over the first few cycles of fault current. Using a simplified circuit model analysis the experimental results are used to deduce materials parameters such as the superconductor current density and resistivity. The development prospects for high-T{sub c} superconducting fault current limiters are discussed.

V.A. Aresteanu

Papers

Design considerations for an inductive high T/sub c/ superconducting fault current limiter

Test results for laboratory scale inductive high-T/sub c/ superconducting fault current limiters