Power systems are becoming more and more complex in nature due to the integration of several power electronic devices. Protection of such systems and augmentation of reliability as well as stability highly depend on limiting the fault currents. Several fault current limiters (FCLs) have been applied in power systems as they provide rapid and efficient fault current limitation. This paper presents a comprehensive literature review of the application of different types of FCLs in power systems. Applications of superconducting and non-superconducting FCLs are categorized as: (1) application in generation, transmission and distribution networks; (2) application in alternating current (AC)/direct current (DC) systems; (3) application in renewable energy resources integration; (4) application in distributed generation (DG); and (5) application for reliability, stability and fault ride through capability enhancement. Modeling, impact and control strategies of several FCLs in power systems are presented with practical implementation cases in different countries. Recommendations are provided to improve the performance of the FCLs in power systems with modification of its structures, optimal placement and proper control design. This review paper will be a good foundation for researchers working in power system stability issues and for industry to implement the ongoing research advancement in real systems.

https://www.mdpi.com/1996-1073/11/5/1025/pdf

Fault Current Limiters in Power Systems: A Comprehensive Review

For that wind plants are connected to an electric power grid through voltage source converter-based high-voltage direct-current (VSC-HVDC) transmission, the improvement of the VSC-HVDC system's robustness against a dc short-circuit fault is critical. This paper suggests the inductive and resistive superconducting fault current limiter (SFCL) to alleviate the fault current and enhance the system's transient behaviors. Each of the two SFCLs is installed in series with the dc transmission line, and once the fault is detected, the current-limiting inductance or resistance will be activated to affect the system characteristics. Herein, wind plants are based on doubly-fed induction generators, and related theoretical derivation and transient simulation analysis are done. From the results, both of the two SFCLs can limit the dc fault current, improve the dc-voltage sags and suppress the power fluctuations. By comparing the specific performance indexes including current-limiting ratio and restraining capability to voltage/power fluctuations, the resistive SFCL is more preferable than the inductive SFCL. At the end, the SFCL optimization technique considering current-limitation, voltage stability, and device cost are discussed, so as to further promote the SFCL's application in the VSC-HVDC system.

Comparison of Inductive and Resistive SFCL to Robustness Improvement of a VSC-HVDC System With Wind Plants Against DC Fault

Concerning that a short-circuit fault happens inside a microgrid system, parts of distributed generation (DG) units may not meet the fault ride-through (FRT) requirements and will be enforced to disconnect. This paper suggests a modified flux-coupling-type superconducting fault current limiter (SFCL) to improve the DG's FRT capability, and investigates the relay protection coordination in the microgrid. The SFCL's structural principle is introduced, and according to the fault characteristic of the microgrid under its grid-connected and islanded statuses, the modified SFCL's application fields are conducted. Furthermore, the directional overcurrent protection and differential protection are proposed for the microgrid's two statuses, respectively. Based on the transient simulations in the MATLAB, the SFCL's positive effects on enhancing the DG's FRT capability can be confirmed, and also it will not affect the relay protection coordination. A comparison of the conventional distance relay protection and the proposed protection scheme is performed, and the latter has a better applicability than the former to match the SFCL. Finally, regarding the impacts of fault type and fault resistance on the FRT operation and the proposed protection, technical discussions are performed preliminarily, and the application value of the SFCL integrated with the proposed protection is clarified further.

Application of a SFCL for Fault Ride-Through Capability Enhancement of DG in a Microgrid System and Relay Protection Coordination

https://purehost.bath.ac.uk/ws/files/152965173/CFS_additonal_information.pdf

Analysis of a new design of the hybrid energy storage system used in the residential m-CHP systems

Superconducting fault current limiters (SFCLs) may play an important role in power-dense electrical systems. Therefore, it is important to understand the dynamic characteristics of SFCLs. This will allow the behavior of multiple SFCLs in a system to be fully understood during faults and other transient conditions, which will consequently permit the coordination of the SFCL devices to ensure that only the device(s) closest to the fault location will operate. It will also allow SFCL behavior and impact to be taken into account when coordinating network protection systems. This paper demonstrates that resistive SFCLs have an inverse current-time characteristic: They will quench (become resistive) in a time that inversely depends upon the initial fault current magnitude. The timescales are shown to be much shorter than those typical of inverse overcurrent protection. A generic equation has been derived, which allows the quench time to be estimated for a given prospective fault current magnitude and initial superconductor temperature and for various superconducting device and material properties. This information will be of value to system designers in understanding the impact of SFCLs on network protection systems during faults and in planning the relative positions of multiple SFCLs.

/pdf/current-time-characteristics-of-resistive-superconducting-f3a6orqa47.pdf

Current–Time Characteristics of Resistive Superconducting Fault Current Limiters

A single-phase, 230 V Superconducting Fault Current Limiter using two Bi2223 HTS tubes with the total critical current 2.5 kA situated in vacuum insulated cryostat has been described in this paper. We designed and manufactured the inductive SFCL with an open core as core shielded type acquired the optimal design parameters by using Finite Element Method. We tested the limiter performances at liquid nitrogen temperature 77 K. We proved that the performances of properly designed limiter with open core could be comparable to the limiter with closed core.

Design and testing of 230 V inductive type of Superconducting Fault Current Limiter with an open core

The high-T/sub c/ superconducting fault current limiter (SFCL) can be classified into resistive, inductive and hybrid types. The inductive type HTSFCL seems to show most prospect due to the simple design (construction) of the secondary superconducting winding in the form of ceramic type BSCCO and for the reduction of current leads. In an inductive type SFCL, ferromagnetic cores for magnetic flux are applied, however open cores are also taken into consideration in order to simplify the construction. The results of experimental and computational investigations of inductive SFCL parameters are presented in this paper.

Properties comparison of superconducting fault current limiters with closed and open core

Superconducting fault current limiters (SFCL) are designed to protect the electrical grid from faults that result from lightning strikes, downed power lines and other system interruptions. The rapid increase of impedance of the SFCL reduces the short current in the circuit. Several coreless constructions of inductive SFCLs have been tested. The space between the windings is the thick of the polyimide film kapton insulation to increase the coupling and reduces the leakage reactance. Both primary and secondary windings have been immersed in liquid nitrogen. The presented solutions reduce the size and the weight of the device. A few limiters based on HTS 1G and HTS 2G tapes has been described, tested and compared.

Tests and Performance Analysis of Coreless Inductive HTS Fault Current Limiters

The fault current limiting feature of the SC transformer with the HTS 2G windings provide protection and significantly reduce wear and tear for circuit breakers and other substation power equipment. A comparison of the short circuit currents of the 64 MVA transformer wound with copper and YBCO 2G HTS tapes is made in this paper. The results of the analysis show that the YBCO 2G tapes enable to built the superconducting transformer with the ability to limit the short-circuit currents. The superconducting windings require special considerations for the induced electromagnetic forces in order to limit them below the allowable tensile stresses. Strongly anisotropic Y-123 tape used in the winding of the transformer will be exposed to different orientations and amplitudes of the local magnetic field. If the transformer is going to act also as a fault current limiter, the uniformity of the transition of the transformer winding is crucial to avoid sectional responses of the transformer. Therefore it is essential to conduct systematic current-magnetic field measurements to define `constant current domain' for the conductor at a given operating temperature.

Fault Current Limitation in Power Network by the Superconducting Transformers Made of 2G HTS

Superconducting fault current limiters (SFCLs) are the most attractive devices for the power network, because limiters can be used to limit the short current in electrical network. This paper presents the design, the numerical model, and the calculated electrical parameters of the new 15-kV class SFCL prototype. The coreless superconducting fault current limiter consists of three windings: a primary and secondary windings made of SF12050 tape and a parallel connected primary copper winding. All windings are inductively coupled and intended to work in liquid nitrogen. The transient magnetic FEM-circuit numerical models of SFCL were used to analyze the current, resistance, and temperature of SFCL in the limitation state.

G. Wojtasiewicz

Papers

Design and testing of 230 V inductive type of Superconducting Fault Current Limiter with an open core

Properties comparison of superconducting fault current limiters with closed and open core

Tests and Performance Analysis of Coreless Inductive HTS Fault Current Limiters

Fault Current Limitation in Power Network by the Superconducting Transformers Made of 2G HTS

Design and Numerical Analysis of the 15 kV Class Coreless Inductive Type SFCL