Model Of Superconducting Fault Current Limiter Research Articles

Impact of Copper Stabilizer Thickness on SFCL Performance with PV-Based DC Systems Using a Multilayer Thermoelectric Model

Utilizing renewable energy sources (RESs) to their full potential provides an opportunity for lowering carbon emissions and reaching a state of carbon neutrality. DC transmission lines have considerable potential for the integration of RESs. However, faults in DC transmission lines are challenging due to the lack of zero-crossing, large fault current magnitudes and a short rise time. This research proposes using a superconducting fault current limiter (SFCL) for effective current limitation in PV-based DC systems. To properly design an SFCL, the present work investigates the effect of copper stabilizer thickness on SFCL performance by using an accurate multilayer thermoelectric model. In the MATLAB/Simulink platform, the SFCL has been modeled and tested using different copper stabilizer thicknesses to demonstrate the effectiveness of the SFCL model in limiting the fault current and the impact of the copper stabilizer thickness on the SFCL’s performance. In total, four different thicknesses of the copper stabilizer were considered, ranging from 10 μm to 80 μm. The current limitation and voltage profile for each thickness were evaluated and compared with that without an SFCL. The developed resistance and temperature profiles were obtained for various thicknesses to clarify the mechanisms behind the stabilizer-thickness impact. An SFCL with an 80 µm copper stabilizer can reduce the fault current to 5.48 kA, representing 71.16% of the prospective current. In contrast, the fault current was reduced to 27.4% of the prospective current (2.11 kA) when using a 10 µm copper stabilizer.

Power consumption and cumulative energy of bridge type SFCL with simultaneous quench

A bridge type superconducting fault current limiter (SFCL) with two high-temperature superconducting (HTSC) elements using flux-coupling is proposed to reduce the influence of short-circuit accidents. A laboratory-scale prototype SFCL was fabricated and short-circuit test was conducted. The power consumption and the accumulated energy were compared and analyzed according to the winding current when the number between N1 and N2 coil changed during the fault period. In addition, the operating range of the flux linkage and the variation of the magnetizing force area were compared according to the magnetizing current. The usefulness of the proposed SFCL was confirmed through analysis of the fault current limiting operation characteristics and the energy consumed by the simultaneous quench of two HTSC elements. As a future study, we will apply this modified bridge-type SFCL model to a direct current (DC) distribution system. First, after establishing a DC short circuit accident test environment, this SFCL is constructed in front of the DC load and the fault occurrence resistor to measure and analyze the DC fault current limiting characteristics.

Superconducting fault current limiter (SFCL): Experiment and the simulation from finite-element method (FEM) to power/energy system software

The superconducting fault current limiter (SFCL) has been regarded as one of most popular superconducting applications. This article reviews the modern energy system with two major issues (the power stability and fault-current), and introduces corresponding approaches to mitigate these issues, including the importance of using SFCL. Then the article presents the experiment of a resistive-type SFCL used for a power electronic circuit. The experiment well matched the advanced finite-element method (FEM) SFCL model, from which the reliability of FEM SFCL model was confirmed. Afterwards, the FEM model and the power system software PSCAD were used to model a large-scale resistive-type SFCL. Under the same simulation conditions the FEM model well matched the PSCAD model. The FEM method has the advantages of offering specific electromagnetic modeling on superconducting part. The PSCAD SFCL model has much faster simulation speed and can directly cope with all ranges of power networks. This article presents a new vision and an all-in-one study to link the experiment, the numerical model, and the power/energy system software model, and their agreement can be extremely helpful for researchers and engineers to find useful evidences and reliable methods to confidently carry out successful SFCL designs for the electrical energy system.

Analysis on Double Quench and Instantaneous Power of SFCL Using Two Magnetically Coupled Windings According to Winding Direction

In this study, the characteristics of the double quench and instantaneous power of a superconducting fault current limiter (SFCL) using two magnetically coupled windings were analyzed. In the proposed model of SFCL, two magnetically coupled windings are wound on the iron core and each winding is connected to one superconducting element. When a fault occurs, the SFCL can limit the fault current by the double quench occurrence of two superconducting elements. In order to analyze the influence of the winding direction on the fault current limiting characteristics of the proposed SFCL, two magnetically coupled windings were designed to allow the same and the reverse directions. From the simulated short circuit experiment, the currents and the voltages of two coupled windings and two superconducting elements were measured and the instantaneous power and the double quench occurrence were analyzed. It was confirmed from the experimental results analysis that the fault current limiting characteristics of the SFCL were more favorable in the reverse winding direction than in the same winding direction.

Application of a novel approach of resistive‐type superconducting fault current limiter with a fast protection system in multi‐terminal direct current network

The key obstacle in the realization of Multi-terminal HVDC (MTDC) grids is the lack of existing commercial protection that a device can withstand the DC fault. Although different HVDC circuit breaker technologies have been investigated and demonstrators tested by manufacturers, the innovation of such devices to ensure a reliable protection system has not been proven yet due to the maximum braking capability limitation especially in MTDC grids. To this, a combination of Superconducting Fault Current Limiter (SFCL) technology with a fast DC circuit breaker could bring a solution to this bottleneck. In this work, a new application of an accurate model of resistive-type SFCL (rSFCL) considering both the electrical and thermal behaviors is proposed to work together with a proactive hybrid DC circuit breaker (PHCB) to fulfill the whole system protection. The viability of the proposed approach is verified under a worst DC fault case-scenario that imposed in a five-terminal MTDC meshed grid. The numerical analysis and simulations are carried out using (EMTP-rv®) software, while the obtained results show how significantly the proposed rSFCL can reduce the fault current and enhance the breaking capability. Also, a positive interaction has been observed between the rSFCL and PHCB in terms of design sizing and operation performance.

Study on the Alliance between SFCL and Hybrid DC Circuit Breaker for Protecting HVDC Grid

Breaking the DC fault in HVDC grid is the greatest challenge for DC grid protection system. Although there are many scientific researches investigating the high voltage DC breakers, yet, there is still always a trade-off between the interruption time and the breaking capability. Therefore, combining between the superconducting fault current limiter (SFCL) technology with a fast DC circuit breaker could bring a solution to this limitation. In this work, an accurate model of resistive-type SFCL (r-SFCL) considering the electro-thermal behaviour, is proposed to be placed in series with ABB proactive hybrid DC circuit breaker (PHCB). To test the viability of the system, a pole-to-pole DC fault scenario was imposed in a HVDC grid. The numerical analysis was undertaken with (EMTP-RV®) software, while the simulation results show how effectively the SFCL can reduce the fault current below the maximum breaking capability. Also, it is concluded that there is a positive interaction between the r-SFCL and PHCB.

On Short-Circuit Current Calculations Including Superconducting Fault Current Limiters (ScFCLs)

This paper introduces a novel modeling approach for short-circuit studies incorporating superconducting fault current limiters (ScFCLs). The conventional formulation for short circuit studies, based on symmetrical components, has been extended to include the nonlinear limiting features of the ScFCL. Indeed, this is a novel iterative modeling method that has been derived from the classical calculations of short circuits. The operating point of the ScFCL is computed in the abc reference frame, while the solution of the whole network, including all of its components, is achieved using symmetrical components. The ScFCL model, which includes various parallel-connected superconducting tapes, is derived for the positive, negative, and zero sequences. Given that the resistance of the ScFCL is nonlinear and depends on the current flow, an iterative process is used to carry out short-circuit calculations. To validate the proposed method, radial and meshed distribution networks were studied. The solutions derived from the proposed approach and the ones obtained from the electromagnetic transient software Alternative Transients Program-Electromagnetic Transients Program were compared with both solutions agreeing very well with each other. The standard IEEE 14-bus test system, slightly modified to include two ScFCLs, was additionally simulated to demonstrate the practicality of the new approach in larger networks.

Coordination of overcurrent protection relays in networks with superconducting fault current limiters

The paper concerns coordination of overcurrent (OC) protection relays in power networks with superconducting fault current limiters (SFCL). At the beginning, information about designed SFCL and conditions that ensure overcurrent protection coordination are presented. Next, settings of the overcurrent relays were determined for a sample network with SFCL model installed. The considered HV/MV power system was modeled in the ATP/EMTP software and the effects of OC relays coordination was analyzed. At the end, conclusions from conducted studies and resulting guidelines for protection coordination are provided.

Multi-scale model of resistive-type superconducting fault current limiters based on 2G HTS coated conductors

In order to plan the integration of superconducting fault current limiters (SFCLs) in power systems, accurate models of SFCLs must be made available in commercial power system transient simulators. In this context, we developed such a model for the EMTP-RV software package, a power system transient simulator widely used by power utilities. The model can be used with any resistive-type SFCL (rSFCL) made of high temperature superconductor (HTS) tapes, which are discretized in ‘electro-thermal elements’. Those elements consist solely of electric circuit components, and are used to represent portions of tape of various sizes and dimensions (a ‘multi-scale’ approach). Both the electrical and thermal behaviors of the tape are modeled, including interfacial effects, nonlinear properties of materials and heat transfer to the surrounding environment. Such a multi-scale model can simulate accurately both the local quench dynamics of HTS tapes (microscopic scale) and the global impact of the rSFCL on the power system (macroscopic/system scale). In this paper, the model is used to compute phenomena such as propagation velocity of a hot spot and heat diffusion through the thickness of the tape. Results were verified by comparing EMTP-RV results with finite element simulations. In addition to the development of the multi-scale model itself, which is the major contribution of this paper, the use of the model allowed us to determine the conditions of validity of the commonly used ‘homogenization’ of the thermal properties across the tape thickness. Indeed, when the current flowing into the rSFCL is slightly above its critical current Ic (and up to ), very important errors in the power waveforms arise, leading to potentially wrong decisions of protection systems. Homogenized thermal models should thus be used with great care in practice.

A Fault Current Limiter Circuit to Improve Transient Stability in Power System

Short circuit current limitation in distribution system utilities can be an operational approach to improve power quality, since the estimated voltage sag amplitude during faults may be intensely reduced. The application of superconducting fault current limiter (SFCL) is projected here to limit the fault current that occurs in power system. SFCL utilizes superconductors to instantaneously decrease the unanticipated electrical surges that happen on utility distribution and power transmission networks. SFCL considerably decrease the economic burden on the utilities by reducing the wear on circuit breakers and protecting other expensive equipment. The designed SFCL model is used for determining an impedance level of SFCL according to the fault current limitation necessities of different types of the smart grid system. The representation of this paper about to see the optimum resistive value of SFCL for enhancing the transient stability of a power system. The assessment of optimal resistive value of the SFCL connected in series in a transmission line with a conductor throughout a short circuit fault is consistently determined by applying the equal-area criterion supported by power-angle curves. A Simulink based primary model is developed and additionally the simulation results for the projected model are achieved by using MATLAB.

Mitigation of commutation failures in LCC–HVDC systems based on superconducting fault current limiters

Commutation failure in line commutated converter based HVDC systems cause severe damages on the entire power grid system. For LCC–HVDC, thyristor valves are turned on by a firing signal but turn off control is governed by the external applied AC voltage from surrounding network. When the fault occurs in AC system, turn-off control of thyristor valves is unavailable due to the voltage collapse of point of common coupling (PCC), which causes the commutation failure in LCC–HVDC link. Due to the commutation failure, the power transfer interruption, dc voltage drop and severe voltage fluctuation in the AC system could be occurred. In a severe situation, it might cause the protection system to block the valves. In this paper, as a solution to prevent the voltage collapse on PCC and to limit the fault current, the application study of resistive superconducting fault current limiter (SFCL) on LCC–HVDC grid system was performed with mathematical and simulation analyses. The simulation model was designed by Matlab/Simulink considering Haenam-Jeju HVDC power grid in Korea which includes conventional AC system and onshore wind farm and resistive SFCL model. From the result, it was observed that the application of SFCL on LCC–HVDC system is an effective solution to mitigate the commutation failure. And then the process to determine optimum quench resistance of SFCL which enables the recovery of commutation failure was deeply investigated.

Modeling and Simulations of BSCCO Superconducting Fault Current Limiter for Fault Ride through Capability Enhancement of DFIG Wind Turbines

To investigate the effects of wind power system with Superconducting Fault Current Limiter (SFCL), this paper presents modeling and simulations of a High Temperature Superconductor (HTS) SFCL, which is BSCCO (Bi-2212), for fault ride through capability enhancement of DFIG wind turbines. The Bi-2212 model is completely implemented on DIgSILENT PowerFactory, which is the most reliable software for electrical power engineering. The equations of the SFCL consist of temperature, heat energy and resistance characteristics with distinctive superconducting states to demonstrate real time circumstances of the SFCL. The developed SFCL model is applied to study the problem of enhancement of fault ride through capability of DFIG. The simulation results demonstrate that the SFCL plays a very significant role to improve the fault ride through capability of DFIG with superior performance under Italian grid code requirement as the benchmark.

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

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.

초전도 한류기 적용시 배전계통의 신뢰도 비용 평가

In this paper, the effects of superconducting fault current limiter (SFCL) installed in power distribution system on reliability are evaluated and analyzed. The fault current will be decreased in power distribution system with SFCL because of the increased impedance of SFCL. The decreased fault current will improve the voltage drop of the bus of substation. The voltage drop is an important factor of power distribution system reliability. In this paper, improvement of reliability worth is analyzed when SFCLs are installed at the starting point in power distribution system. First, resistor-type SFCL model is used in PSCAD/EMTDC. Next, typical power distribution system is modeled. Finally, when the SFCLs with impedance 0.5 [Ω] are installed in feeder, power distribution system reliability is evaluated. Also, the improvement effect of reliability worth including the effect of voltage sag is analyzed using customer interruption cost according to whether or not SFCL is installed.

Coordinated Control Of SFCL And SVC For Power System Transient Stability Improvement

Transient stability is the ability of the power system to maintain synchronism when subjected to a severe disturbance, such as a short circuit on a transmission line. To improve stability, inductive type superconducting fault current limiter (SFCL) and shunt FACTS Controller (SVC) can be effectively used. This paper proposes the use of combined model based SFCL and SVC for enhancing the transient stability of a multi-machine power system considering the automatic voltage regulator. The main role of the proposed combined model is to attain at the same time a flexible control of reactive power using SVC Controller and to reduce fault current using superconducting technology based SFCL. In the present work, modification of the admittance matrix method is used for modeling of SFCL; Critical Clearing Time (CCT) has been used as an index for evaluated transient stability. The transient stability is assessed by the criterion of relative rotor angles, using numerical integration method. The effectiveness of the proposed combined model is tested on the IEEE benchmarked four-machine two-area test system applied to the case of three-phase short circuit fault in one transmission line. A simulation results are presented in this document. DOI:  http://dx.doi.org/10.11591/telkomnika.v13i3.7175

초전도 한류기를 주변압기 접지선에 설치시 배전계통의 순간전압품질 분석

In this paper, voltage quality improvement is analyzed in case of Superconducting Fault Current Limiter (SFCL) installed in grounding line of main transformer in power distribution system. First, a resistive-type SFCL model is used. Next, Korean power distribution system is modeled. Finally, when SFCL is installed in the starting point of feeder and grounding line of main transformer, voltage qualities are evaluated according to various fault locations and resistance values of SFCL using PSCAD/EMTDC. The voltage quality results in case of grounding line are compared with the voltage in case of feeder.

Voltage Sag Analysis in Loop Power Distribution System With SFCL

In this paper, the effects of a superconducting fault current limiter (SFCL) installed in loop power distribution systems on voltage sags are assessed and analyzed. The power distribution system will be operated to a type of loop. In this case, voltage drops (sags) are severe because of the increased fault current when a fault occurs. If SFCL is installed in the loop power distribution system, the fault current decreases based on the location and resistance value of the SFCL, and voltage sags are improved. In this paper, the improvement of the voltage sag is analyzed according to the fault location, resistance value of SFCL, and the length of the loop power distribution system. First, a resistor-type SFCL model is used using the PSCAD/EMTDC. Next, the loop power distribution system is modeled. Finally, when the SFCL is installed in the radial or loop power distribution system with various lengths, voltage sags are evaluated according to various fault locations. The results of voltage sag analysis in the loop system are compared with the voltage sags in radial power distribution system.

Experimental and Numerical Study of Co-ordination of Resistive-Type Superconductor Fault Current Limiter and Relay Protection

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.

Comparative Study of Resistive and Inductive Superconducting Fault Current Limiters SFCL for Power System Transient Stability Improvement

This paper presents a comparative study of resistive and inductive superconducting fault current limiter (SFCL) for power systems transient stability improvement. Two applications of transient stability assessment are presented in this paper: The first shows the efficiency of the resistive and inductive SFCL in series with a generator, the second uses SFCL installed in series with a transmission line. SFCL can just be operated during the period from the fault occurrence to the fault clearing; the modeling and the effect of SFCL has been investigated to have higher benefits for the power system. In the present work, modification of the admittance matrix method is used for modeling of SFCL; Critical Clearing Time (CCT) has been used as an index for evaluated transient stability. The transient stability is assessed by the criterion of relative rotor angles, using the Runge–Kutta method. The effectiveness of the proposed method is tested on the WSCC3 nine-bus system applied to the case of three-phase short circuit fault in one transmission line. A simulation and comparison are presented in this document.

Modeling and Simulation of Resistive Superconducting Fault-Current Limiters

Superconducting fault-current limiters (SFCL) offer ideal performance in electrical power system. The design of SFCL has to be both flexible, to allow an easy adaptation to the specific requirements of each particular application, and a high quality standard with reproducible properties. Up to now no simulation model of SFCL has been validated or introduced in the Library of MATLAB software. In this paper a simulation model for a novel re- sistive type superconducting fault-current limiter is pro- posed. This model includes the electric field-current den- sity (E-J ) characteristics of High-Temperature Supercon- ductors (HTS). A graphical interface using Graphical User Interface (GUI) of MATLAB is developed in order to ease the operation of the proposed model. This one facilitates the introduction or the parameter modification of materials candidate to a SFCL model. Thus, the operation characteris- tics and limitation behavior of SFCL have been investigated. The developed model accurately predicted the current-time waveforms achievable with typical limiters, and improved standard of understanding concerning the fault-current lim- itation mechanisms.