Non-superconducting Fault Current Limiter Research Articles

Testing and validation of a modified bride-type nonsuperconducting fault current limiter

As the amount of distributed generation (DG) integrated into the distribution network keeps increasing, this leads to an increase in the levels of fault current in the network, and this will result in the network having a fault current above what the existing protecting devices can handle. Hence, an upgrade of protective devices will be necessitated. A lot of techniques have been developed to mitigate against high fault currents. Some of these techniques with their limitations include current-limiting fuses that need constant replacement after an operation; circuit breakers that are very expensive for high current applications; isolation transformers that result in additional network power losses; and current-limiting and air-core reactors that impede the voltage stability of the network. Following these shortcomings, fault current limiters saw the light as the paramount solution to restrain fault currents in the distribution network. This research work is a follow-up of previous research that was on the design of a modified bridge-type nonsuperconducting fault current limiter (MBNSFCL) for application in the distribution network. In this paper, the designed MBNSFCL is tested and validated on two standard IEEE distribution networks, which are the IEEE 13 and the 33 node test networks. The simulation was done using PSCAD/EMTDC. In the case of the IEEE 13 node, the occurrence of a 3 phase to ground fault on the swing bus leads to the source current shooting from an amplitude of 0.602 kA on phase A, 0.335 kA on phase B, and 0.356 kA on phase C to 34.996 kA on phase A, 35.126 kA on phase B, and 34.983 kA on phase C. The fitting of the MBNSFCL into the test network restrains the fault current below the nominal line current, a level at which the circuit breaker can comfortably clear. The virtue of the MBNSFCL is also established when tested on the IEEE 33 node test network. This reveals the reliability of the proposed MBNSFCL for application in the distribution network.

Double integral sliding mode controller based bridge-type flux-coupling non-superconducting fault current limiter to protect DFIG-based multi-machine power system under transient-state

This paper proposes a double-integral sliding mode controller (DISMC) based bridge-type flux-coupling non-superconducting fault current limiter (BFC-NSFCL) to enhance the fault ride-through (FRT) capability of a DFIG-based wind farm connected to a multi-machine power system. At first, a complete modeling of the BFC-NSFCL is derived to understand its behavior during the normal and fault period more accurately. Then, the DISMC is designed based on that dynamic model obeying the double-integral theory, along with the single-integral sliding mode controller (SISMC) and non-integral sliding mode controller (NISMC) for comparison purpose. Finally, the performance of the DISMC in controlling the BFC-NSFCL has been analyzed and verified by comparing with that of the SISMC and the NISMC. The DISMC removes the chattering problems induced by the traditional SMCs and improves the transient performance by reducing the overshoot and steady-state error by implementing double-integral action. All the graphical and mathematical analyzes favor the DISMC based BFC-NSFCL under symmetrical and unsymmetrical fault (both temporary and permanent) scenarios.

A modified bridge-type nonsuperconducting fault current limiter for distribution network application

The electrical distribution network is undergoing tremendous modifications with the introduction of distributed generation technologies which have led to an increase in fault current levels in the distribution network. Fault current limiters have been developed as a promising technology to limit fault current levels in power systems. Though, quite a number of fault current limiters have been developed; the most common are the superconducting fault current limiters, solid-state fault current limiters, and saturated core fault current limiters. These fault current limiters present potential fault current limiting solutions in power systems. Nevertheless, they encounter various challenges hindering their deployment and commercialization. This research aimed at designing a bridge-type nonsuperconducting fault current limiter with a novel topology for distribution network applications. The proposed bridge-type nonsuperconducting fault current limiter was designed and simulated using PSCAD/EMTDC. Simulation results showed the effectiveness of the proposed design in fault current limiting, voltage sag compensation during fault conditions, and its ability not to affect the load voltage and current during normal conditions as well as in suppressing the source powers during fault conditions. Simulation results also showed very minimal power loss by the fault current limiter during normal conditions.

Application of Thyristor Bridge-Type Non-Superconducting FCL with Buck Series Charging to Improve the FRT Capability of the DFIG System

Wind power generation is observing a significant use of doubly-fed induction generator (DFIG) due to its improved efficiency, but the converter used in the configuration is sensitive to the presence of a fault in the grid. This paper presents a fault ride-through (FRT) configuration, which includes a thyristor-based bridge-type non-superconducting fault current limiter (ThyBT-NSFCL) augmented with a buck converter. It has been observed that the proposed topology works fine under a temporary symmetrical fault. The analytical analysis has been carried out to observe the operating principle of the proposed ThyBT-NSFCL under both normal and fault conditions. A comparative study with other topologies such as switched impedance transformer-type non-superconducting fault current limiter (TT-NSFCL), series dynamic breaking resistor (SDBR), and without any current limiter (WCL) have been done to show the effectiveness of the proposed topology. The simulation results show that the proposed ThyBT-NSFCL is a better fault current limiter as compared with other limiters like TT-NSFCL, SDBR, and WCL. The simulation of the proposed ThyBT-NSFCL connected in series with a DFIG system is carried out using PSCAD/EMTDC software. The performance of the proposed topology is quite good, and it can be used as a reliable limiter for future wind energy applications.

Fault Ride Through Capability Improvement of DFIG Based Wind Farm Using Nonlinear Controller Based Bridge-Type Flux Coupling Non-Superconducting Fault Current Limiter

High penetration of Doubly Fed Induction Generator (DFIG) into existing power grid can attribute complex issues as they are very sensitive to the grid faults. In addition, Fault Ride Through (FRT) is one of the main requirements of the grid code for integrating Wind Farms (WFs) into the power grid. In this work, to enhance the FRT capability of the DFIG based WFs, a Bridge-Type Flux Coupling Non-Superconducting Fault Current Limiter (BFC-NSFCL) is proposed. The effectiveness of the proposed BFC-NSFCL is evaluated through performance comparison with that of the Bridge-Type Fault Current Limiter (BFCL) and Series Dynamic Braking Resistor (SDBR). Moreover, a dynamic nonlinear controller is also proposed for controlling the operation of the BFC-NSFCL. Extensive simulations are carried out in the MATLAB/SIMULINK environment for both symmetrical and unsymmetrical temporary as well as permanent faults. Based on the simulation results and different numerical analysis, it is found that the proposed nonlinear controller based BFC-NSFCL is very effective in enhancing the FRT capability of the WF. Also, the BFC-NSFCL outperforms the conventional BFCL and SDBR by maintaining a near-seamless performance during various grid fault situations.

Low-cost Non-superconducting DC-fault Current Limiter for the Enhancement of Low-voltage Ride Through Capability of Doubly Fed Induction Generator

ABSTRACT The wind generation system shares a significant portion of power to the grid, hence, it is necessary for the wind systems to remain coupled to the grid under any circumstances. Earlier wind systems were permissible to detach under any disorders and protection issues. Nonetheless, the disconnection of the wind system affects the stability of the entire grid. In order to overcome those issues, some ride-through schemes should be implemented. The objective of the proposed paper is to provide an effective ride through a scheme with lower cost for doubly fed induction generator based wind energy conversion system. The proposed method includes a non-superconducting DC fault current limiter placed in between the rotor side converter and grid side converter, which effectively restricts the rotor over current, stator over current, DC link voltage, and electromagnetic torque within their safety limit. The effectiveness of the paper is revealed by comparing the result obtained using three phase resistive-super conducting fault current limiter with the conventional vector control scheme. Also, the proposed method is predicated to be cost effective than other FRT techniques.

Fault Ride through Capability Augmentation of a DFIG-Based Wind Integrated VSC-HVDC System with Non-Superconducting Fault Current Limiter

This paper proposes a non-superconducting bridge-type fault current limiter (BFCL) as a potential solution to the fault problems of doubly fed induction generator (DFIG) integrated voltage source converter high-voltage DC (VSC-HVDC) transmission systems. As the VSC-HVDC and DFIG systems are vulnerable to AC/DC faults, a BFCL controller is developed to insert sizeable impedance during the inception of system disturbances. In the proposed control scheme, constant capacitor voltage is maintained by the stator VSC (SVSC) controller, while current extraction or injection is achieved by rotor VSC (RVSC) controller. Current control mode-based active and reactive power controllers for an HVDC system are developed. Balanced and different unbalanced faults are applied in the system to show the effectiveness of the proposed BFCL solution. A DFIG wind-based VSC-HVDC system, BFCL, and their controllers are implemented in a real time digital simulator (RTDS). The performance of the proposed BFCL control strategy in DFIG-based VSC-HVDC system is compared with a series dynamic braking resistor (SDBR). Comparative RTDS implementation results show that the proposed BFCL control strategy is very efficient in improving system fault ride through (FRT) capability and outperforms SDBR in all cases considered.

A Modified Bridge Switch-Type Flux-Coupling Nonsuperconducting Fault Current Limiter for Suppression of Fault Transients

This paper proposes a modified bridge switch-type flux-coupling nonsuperconducting fault current limiter (BSFC-NSFCL) for suppressing the fault current and voltage sag. A flux-coupling reactor and a bidirectional bridge switch are combined to perform the functions of steady-state line current sharing and fault current suppression. The modified BSFC-NSFCL mainly utilizes the magnetic flux cancellation effect to make the limiter behave as a short circuit on the circuit during normal operation. Hence, there is almost no impact on the power system when the limiter is used. When a fault event occurs, the bridge switch turns off immediately, and then, the magnetic flux cancellation effect disappears. Thus, the impedance of primary coil inserts into the circuit to restrict the fault current and voltage sag phenomena. Once the fault is removed, the bridge switch turns on again, and the BSFC-NSFCL recovers to the normal operation. The modified NSFCL is more cost-effective and easy to be implemented than the flux-coupling superconducting fault current limiter. Theoretical analysis for the BSFC-NSFCL has been fully developed and proven by MATLAB software. Finally, the analytical, simulated, and experimental results have been carried out to verify the feasibility and performance of the proposed BSFC-NSFCL.

A Novel Structure for Bridge-Type Fault Current Limiter: Capacitor-Based Nonsuperconducting FCL

Taking into account extension of power systems, their interconnections, and increment of load demand, power capacity of networks is increased and the impedance of sources is decreased. Such variations in power systems resulted to occurring high ratings of fault currents. Fault current limiter (FCL) can be practically utilized in order to interrupt fault currents to a specified amount without requirement to upgrading protection devices. In this paper, a novel simple structure for nonsuperconducting FCL (NSFCL), which is called capacitor-based FCL (CBFCL), is proposed for limiting the high ratings of fault currents in power networks. The proposed NSFCL circuit is based on transferring electrical energy to a capacitor during fault occurrence, which can be used after fault removal. Simulation of the proposed NSFCL structure is done and the results are provided and analyzed. Additionally, the operation of the circuit is experimentally studied, and the similarity between the simulation results and the experimental results is validated. The provided simulation and experimental results ensure the practicability and possibility of employment of the proposed CBFCL.

Multilevel Nonsuperconducting Fault Current Limiter: Analysis and Practical Feasibility

A new topology for nonsuperconducting fault current limiter (NSFCL) based on multilevel switching strategy is proposed in this paper. The proposed multilevel NSFCL circuit aims to control the high-level fault current by inserting different resistances in the circuit. Due to interrupting the fault current based on multilevel switching strategy which results in the decrement of switching numbers, power loss will be reduced and lifetime of the utility devices will be increased. The proposed NSFCL structure has the capability of limiting the fault current based on obtained quantities from current sensors. The proposed NSFCL topology which has no effect on voltage and load currents of the utility, ensures a high level system protection. The analysis of normal and fault conditions of the proposed multilevel NSFCL have been provided and experimental results are demonstrated to prove feasibility of the proposed structure.

Performance analysis of diode-bridge-type non-superconducting fault current limiter in improving transient stability of DFIG based variable speed wind generator

The application of doubly-fed induction generator (DFIG) is very effective in the fast-growing wind generator (WG) market. The foremost concern for the DFIG based WG system is to maintain the transient stability during fault, as the stator of the DFIG is directly connected to the grid. However, according to the grid code, DFIG needs to remain connected to the network even during the fault. Therefore, transient stability enhancement of the DFIG is very important. In this paper, to achieve this goal a diode-bridge-type nonsuperconductor fault current limiter (NSFCL) is proposed to augment the transient stability of the DFIG based WG system. A three-line-to-ground (3LG), double-line-to-ground (2LG) and single-line-to-ground (1LG) faults were applied to one of the double-circuit transmission lines of the test system to investigate the proposed NSFCL transient stability performance. Besides, a DC resistive superconducting fault current limiter (SFCL), bridge-type fault current limiter (BFCL) and series dynamic braking resistor (SDBR) are also considered to compare their performance with the proposed NSFCL. Simulations were carried out in Matlab/Simulink software. Simulation results show that the NSFCL enhances the transient stability of the DFIG system. Moreover, the NSFCL works better than the DC resistive SFCL, BFCL and SDBR in every aspect.

Analysis of a Switched Impedance Transformer-Type Nonsuperconducting Fault Current Limiter

This paper proposes a nonsuperconducting fault current limiter (NSFCL) topology and control strategy. The switched impedance transformer-type NSFCL topology is optimized to protect against short transients and to work in conjunction with other fuses or circuit breakers, hence has the merits of being simple, low cost, and compact. A prototype has been designed and built for a three-phase 600-V RMS,L-L system. It has been tested in a UL-certified high-power test lab with 5-A normal current and 100-kA potential fault current.

Nonsuperconducting Fault Current Limiter With Controlling the Magnitudes of Fault Currents

In this paper, a diode-bridge-type nonsuperconductor fault current limiter (NSFCL) is proposed. The structure has the capability of controlling the DC reactor current that yields to control the magnitude of fault current. In order to control the magnitude of DC reactor current, a discharging resistor is used in the proposed structure. By controlling the magnitude of DC reactor current, it is possible to reduce the current rating and inductance of DC reactor. In addition, a series connection of DC voltage source with DC reactor is used to compensate the power loss of both nonsuperconducting dc reactor and diodes of fault current limiters (FCLs). By means of proposed NSFCL, it is possible to eliminate all disconnecting switches in the distribution network. The simulation and experimental results are presented to clarify the theory and possibility of implementation of the proposed NSFCL.