Hybrid Fault Current Limiter Research Articles

A capacitance-resistance hybrid fault current limiter based on thyristor

A capacitance-resistance hybrid fault current limiter based on thyristor

Novel hybrid fault current limiter with hybrid resonant breaker in multi-terminal HVDC transmission system

Novel hybrid fault current limiter with hybrid resonant breaker in multi-terminal HVDC transmission system

Development of a Hybrid Fault Current Limiter Using Liquid Metal for Large Capacity MVdc Power Systems

A hybrid fault current limiter (FCL) for medium voltage direct current (MVDC) power systems is introduced in this paper. It achieves low operation loss and high current limiting resistance through the combination of a fast mechanical switch, a magnetic induction module and a number of liquid metal units (LMUs). Firstly, the parameters of the magnetic induction module are designed to achieve a desired fault current commutation process. Then, the working principle of LMU is introduced, and its resistance properties corresponding to the liquid metal arc are studied in detail. Equations are deduced to model the V-I characteristic of LMU. Thus the current limiting performance of the topology can be simulated. To verify the feasibility of the FCL, a 5-kV/5-kA prototype is developed and laboratory tests are implemented. Comparisons with other FCLs are also conducted to demonstrate the advantages of the proposed one. It is concluded that the prototype provides the basis for further commercial product development.

Performance analysis of three-phase hybrid fault current limiter with one commutation circuit

This paper describes the development of a hybrid fault current limiter and interrupting device (HCLID) suitable for low and medium voltage AC or DC industrial installations. By substituting the three-commutation circuit on each phase in HCLID with one controlled commutation circuit, the commutation capacitance, let-through current, volume, and weight can be reduced. Reducing the number of commutations circuit aims at decreasing the initial cost of the (HCLID), which is mainly the focus of the commutation capacitors. The fault current commutation method is introduced as a new current limiting means. This technique is based on the injection of counter-current to the main contacts of the circuit breaker for very fast-breaking of fault currents. The HCLID consists of two electric circuits, one to force the fault current down to zero (commutation circuit) and the other to establish the electro-dynamic force to separate the main contacts. The proposed control method is easy to implement and has a low initial cost. The simulated results presented in the research confirm the validity of the new HCLID over traditional methods. Experimental tests were carried out to validate the proposed method. Simulations and experimental results prove the feasibility of the new HCLID.

New Hybrid Superconducting Fault Current Limiter For Primary Distribution Systems (Dept.E)

In this paper, a new hybrid fault current limiter is proposed for primary distribution systems. It incorporates a high temperature superconducting element in parallel with other two branches. The first is an inductive impedance to share the fault current with. The second branch is a gate-turn off thyristor switch controlled to operate the device in either of two modes: the main mode and the stand-by mode. For the main mode, it controls the temperature of the superconducting element and protects it against damaging excessive heating. Instead, in the stand-by mode, it keeps the device applicable without that superconducting element. The design, control and operation of the device is addressed. Its performance in 11 kV distribution systems with DG is investigated. The effect of fault location and fault incidence angle on the device behavior are explored.

A Thyristor-Based DC Fault Current Limiter With Inductor Inserting–Bypassing Capability

DC fault current limiters (FCLs) are becoming increasingly important for the prompt dc fault clearance of modular multilevel converter (MMC)-based high-voltage direct current (HVdc) grids. This paper proposes a hybrid FCL topology, in which the main current limiting circuit is composed of thyristors, capacitors, and an inductor. Detailed theoretical analysis of the current limiting processes was carried out to check the electrical stresses. The relationship between the voltage stress and the current limiting time was analyzed, and then a design method for the FCL parameters was provided. An effective method for fast bypassing the FCL inductor was proposed to reduce the energy dissipation when fault current is interrupted by a dc circuit breaker (DCCB). The dynamic performance of the proposed approach has shown that the proposed FCL can effectively limit the rate of rising of the dc fault current and reduce the energy dissipation.

Design and Implementation of Fault Current Limiters in Distribution System Using Internet of Things

One of the essential execution of a wireless sensor network is observing hardware. Wireless Sensor Network are capable for taken a toll effective checking over gigantic geo location. Development of keen network depends on the Internet of Things (IoT). Nowadays the fault current levels are increased because of the increasing power demand. Fault Current Limiter(FCL) is used as a protective device to reduce the fault current in distribution system. This paper presents Solid State Fault Current Limiter (SSFCL) and Hybrid Fault Current Limiter (HFCL) to limit the fault current levels for different fault conditions. Also this paper presents the comparison between these two devices with fault current limiting ratio. The performance of the two devices is carried over in IEEE 6-bus system. The simulation and experimental results validate the performance of these two devices to reduce the fault current. The proposed model is executed with SSFCL and HFCL for 60 W three-phase load under various fault conditions. All the fault conditions are observed and controlled through IoT cloud framework.

Current limiting methods for VSC-based DC distribution systems

The lack of mature and reliable fault isolation technologies constrains the development and application of DC distribution systems. In this paper, the protection differences between AC distribution systems and voltage source converter (VSC)-based DC distribution systems are analyzed. The indispensable role of the fault current limiter for the isolation of a DC fault is proposed. Based on the analysis of DC fault, the current limiting effects of resistance and inductance are analyzed. Analyses and corresponding simulation indicate that the resistance and inductance hybrid fault current limiter can protect the of AC source and diodes from overcurrent and limit the rising speed of fault current simultaneously.

A Novel DC Fault Ride-Through Scheme for MTDC Networks Connecting Large-Scale Wind Parks

This paper proposes a novel fault ride-through protection scheme for multiterminal dc (MTDC) networks connecting large-scale offshore wind parks. The proposed scheme introduces an MTDC network with a hybrid fault current limiter (FCL), which consists of a high-temperature superconducting FCL (HTS-FCL) and series braking resistor (SBR) integrated with low-loss mechanical dc circuit breaker (DCCB). The aim of HTS-FCL is to provide fast quenching, limit the dc fault current within the interrupting capacity of the DCCB, and reduce the dc fault current to certain levels such that converters can sustain prolonged periods of operation without blocking. Also, SBR allows automatic reclosing of DCCBs following a temporary fault, thereby enhancing the network security and reliability. Mechanical DCCBs with the proposed hybrid limiter are installed at the terminating points of each dc cable. The proposed protection scheme is based on differential current approaches with fault clearing time of few milliseconds, which gives enhanced network selectivity and reliability. A four-terminal meshed MTDC network with the proposed hybrid FCL is modeled in PSCAD/EMTDC. The obtained simulation results confirm successful dc fault isolation and network recovery for different dc fault scenarios.

Recovery Tests of an Hybrid Current Limiter Composed of a SFCL in Parallel to an Air-Core Power Reactor

The resistive-type superconducting fault current limiters (RSFCL) prototypes using YBCO-coated conductors have shown current limitation for medium voltage class applications for acting time up to 80 ms. By connecting an air-core reactor in parallel with the RSFCL, thus making an hybrid current limiter, one can extend the acting time for up to 1 s. In this work, we report the performance of a hybrid current limiter subjected to an AC peak fault current of 2 kA during 1 s for which within the first 80 ms the SFCL limits the current concurrently with the air-core reactor, and for the remaining 920 ms, only the air-core reactor limits the current. In order to evaluate the actual conditions for subsequent reconnection of RSFCL to the power grid, the hybrid fault current limiter was tested varying the time interval for recovery from 900 ms and 1.2 s, followed again by the concurrent operation of the hybrid limiter during 1 s (SFCL during 80 ms). From this evaluation test, the recovery time can be measured and compared using the voltage peak generated in superconducting module from the first and second fault test. The recovery time was also determined through the pulsed current method (PCM) on short-length sample test. The results showed that the fault current was limited from 1.9 kA down to 514 A after 1 cycle of 60 Hz frequency, with recovery time lower than 1.2 s for two subsequent fault current tests.

A neodymium hybrid fault current limiter

This paper presents a new hybrid type fault current limiter topology for use in distribution systems. The proposed system includes a fast mechanical contact switch, a semiconductor switch, a neodymium magnetic core, and a metal-oxide varistor. A custom control algorithm is developed to detect the fault occurrence and perform the correct switching order of the proposed hybrid fault current limiter. A novel feature included in the proposed hybrid fault current limiter is the ability to control the fault current magnitude through the use of pulse-width modulation. In addition, the Jiles–Atherton method of hysteresis is used to model the nonlinear permeability of the NdFeB core. Simulations are performed using Power System Computer Aided Design (PSCAD) for both a high voltage and a low voltage system. A low voltage (20 V, 1.25 A) hardware system is built to verify the PSCAD simulations, and the results are presented. In conclusion, a comparison between the PSCAD simulations and the hardware experimental results verify the correct modeling of the proposed topology and confirm its feasibility. Copyright © 2014 John Wiley & Sons, Ltd.

Comparison of Four Different Types of Ferromagnetic Materials for Fault Current Limiter Applications

A comparison of neodymium, samarium-cobalt, aluminum-nickel-cobalt, and laminated steel is presented for use in fault current limiter applications. The ferromagnetic material properties are modeled using the Preisach method of hysteresis. The nonlinear inductance of each magnetic core is calculated and displayed. Only the material properties are changed during each consecutive simulation and are subjected to distribution system parameters to assess their fault current limitation applicability. Finite-element analysis is performed on the casing and coils of the mechanical design structure of the new hybrid fault current limiter. A new fault current limiter topology is presented and simulated in Piecewise Linear Electrical Circuit Simulation. The simulated results show the effect of different materials on the current limiter's performance. Conclusions are made that neodymium is the most suitable ferromagnetic material (of the materials tested) for fault current limiter applications.

Suppression of Fault Currents on DG Using Various Fault Current Limiters in Distribution Network

Protection of Distributed Generation (DG) is a challenging task in entire electrical family. DG plays a vital role in advanced power systems engineering. The connection of DG to the distribution network has numerous advantages. Even though it has a advantages, while connecting the DG with existing power system network, the fault current level in many places have often exceeded which causes the abnormal conditions in the entire power system network. In order to reduce the fault current level, various Fault Current Limiters (FCL) are proposed. In this paper hybrid Fault Current Limiter (HFCL) and its applications are proposed to minimize the effect of the DG on the distribution protection system in a radial system during a fault. The simulated results are analysed and compared with a Solid State Fault Current Limiter (SSFCL) and Superconducting Fault Current Limiter (SFCL) using MATLAB simulation. The effectiveness of proposed fault current limiters are determined and examined in the test system.

Improvement in operational characteristics of KEPCO’s line-commutation-type superconducting hybrid fault current limiter

A 22.9kV class hybrid fault current limiter (FCL) developed by Korea Electric Power Corporation and LS Industrial Systems in 2006 operates using the line commutation mechanism and begins to limit the fault current after the first half-cycle. The first peak of the fault current is available for protective coordination in the power system. However, it also produces a large electromagnetic force and imposes a huge stress on power facilities such as the main transformer and gas-insulated switchgear. In this study, we improved the operational characteristics of the hybrid FCL in order to reduce the first peak of the fault current. While maintaining the structure of the hybrid FCL system, we developed a superconducting module that detects and limits the fault current during the first half-cycle. To maintain the protective coordination capacity, the hybrid FCL was designed to reduce the first peak value of the fault current by up to approximately 30%. The superconducting module was also designed to produce a minimum AC loss, generating a small, uniform magnetic field distribution during normal operation. Performance tests confirmed that when applied to the hybrid FCL, the superconducting module showed successful current limiting operation without any damage.

Novel Design of the Structure of a Non-Inductive Superconducting Coil

A non-inductive coil is an essential element of a resistive superconducting fault current limiter (FCL). A bifilar pancake type non-inductive coil, which is most common type, has two drawbacks; difficulty of paralleling tapes and a high risk of electrical breakdown at the terminal part. Although the bifilar type is simple as an element, large-scale FCL needs quite a number of series and parallel connections between elements. To make a non-inductive coil using conventional inductive elementary coils, we propose a novel structure of the coil. It looks like a toroid but entire inductance is near zero. This coil can overcome the drawbacks of conventional bifilar coil. In this paper, we confirm the new concept by numerical analyses. A few kinds of new models are compared, and then we concluded the proposed toroidal shape one is most suitable. This new structure coil can help implement of a hybrid FCL which is to generate the magnetic field at only fault.

이종초전도 코일을 이용한 하이브리드형 한류기의 제작 및 단락실험

Hybrid fault current limiters (FCL) have been researched at Yonsei University. The hybrid FCL has advantages such as having a rapid response to a sudden fault situation and a fast recovery time from a quench. It consists of an asymmetric HTS coil, a switching module, and a bypass reactor. The asymmetric HTS coil is wound with two different types of HTS wires in an opposite direction so that it has nearly zero inductance at the superconducting state. When the quench occurs at the fault state, a strong magnetic field is generated from the asymmetric coil because of different quench characteristics of two HTS wires, and then a repulsive force is induced in the switching module. The force opens the switch and the fault current is pushed into the bypass reactor. In this research, we analyzed the cause of the repulsive force and confirmed, experimentally and computationally, that the magnitude of a repulsive force is varied by changing the gap distance between the asymmetric coil and the switching module. By using the FEM simulation, we calculated the repulsive force with respect to the gap distance and verified that the effect of the gap distance. Then, short circuit test was carried out to confirm the correct operation of the fast switch.

다양한 선재 조합에 따른 이종 초전도 스위치의 특성 실험 및 분석

A Hybrid Fault Current Limiter(FCL) which has more advantages in fast response and thermal characteristics than a simple resistive FCL had been proposed by our group. The Hybrid FCL consists of a resistive FCL for the magnitude of the first peak of fault current, and a fast switch for detecting fault current and generating the repulsive force within a cycle in fault situation. In ideal case, the impedance of the fast switch wound with two other kinds of HTS tape is negligibly zero in normal operation. But, during the fault situation, each HTS tape has different quench characteristics because of asymmetric current distribution. And this phenomenon causes effective flux and this flux opens the switch through the repulsive force applied to a metal plate of the fast switch. The magnitude of the repulsive force affects the switching characteristics of the fast switch. It should be large enough to raise the metal plate up. Otherwise the arc re-out break which are caused by not enough repulsive force to raise the metal plate up can cause unintended operation of the fast switch. In this paper, the numerical calculation of the repulsive force applied to the metal plate of the fast switch in various combinations of HTS tapes was performed by using the short-circuit test and finite element method.

A Study on the Non-Inductive Coils for Hybrid Fault Current Limiter Using Experiment and Numerical Analysis

A Hybrid fault current limiter (FCL) proposed by our group previously is composed of a superconducting coil, a fast switch and a bypass reactor. The superconducting coil wound with two kinds of HTS wire has zero impedance when normal current flows in the coil. However, different quench characteristics of the HTS wire generate magnetic flux in the coil when fault current flows in the coil. As a result, the fast switch was opened by the repulsive force applied to the aluminum plate above the coil. In previous studies, our group verified operating characteristics and feasibility of the fast switch. In this paper, comparison of pancake type and solenoid type non-inductive coil wound with two kinds of the HTS wire was performed by using short-circuit test and finite element method. From these results, short-circuit characteristic of a coil can be acquired and magnitude of the repulsive force and magnetic field can be analysed.

Proposed hybrid superconducting fault current limiter for distribution systems

In this paper, a new hybrid fault current limiter is proposed for primary distribution systems. It incorporates a high temperature superconducting element in parallel with other two branches. The first is an inductive impedance to share the fault current with. The second branch is a gate-turn-off thyristor switch controlled to work in either of two modes. For the main mode, it controls the temperature of the superconducting element and protect it against damaging excessive heating. Instead, it keeps the device applicable without that superconducting element in the auxiliary operation mode. The design, control and operation of the device is addressed. Its performance in 11 kV distribution systems with DG is investigated. The factors affecting the device behavior for different scenarios are explored.

Analytical and Experimental Studies on the Hybrid Fault Current Limiter Employing Asymmetric Non-Inductive Coil and Fast Switch

This paper deals with design and operating test of a novel hybrid FCL. The FCL system consists of a coil, a fast switch and a resistor for bypassing the fault current. The switch is driven by novel non-inductive coil suggested in this paper but an extra driving coil is required for fast switch in existing hybrid FCL. We used two kinds of HTS wire for the coil. The impedance of the coil was negligible in normal operation. But different quench characteristics of HTS wires caused asymmetric current distribution which induced effective magnetic flux in the coil during faults. The switch was opened by repulsive force from this magnetic flux in fast response to the fault. Then, all current were flew through the normal conductive bypass resistor connected in parallel to both the coil and the switch. Electromagnetic analysis of the coil based on finite element method was performed. Also, a small-scale asymmetric non-inductive coil was designed, fabricated and tested. The proposed hybrid FCL system showed fast and efficient current limiting characteristic.