Amalendu Bikash Choudhury

Performance analysis of a saturated iron core superconducting fault current limiter using different core materials

In this paper, a study on various Fault Current Limiters, in particular the Saturated Iron-Core Type High-Temperature Superconducting Fault Current Limiter (SISFCL) has been carried out. The theoretical analysis of the Superconducting Fault Current Limiter has been accomplished using the Jiles-Athertons model of ferromagnetic hysteresis. The simulation of various responses, both electrical and magnetic, of a Saturated Core Superconducting Fault Current Limiter circuit has been realized using MATLAB Programming. Since the performance of the limiter depends on the characteristics of the core material, investigations have been carried out to study the response of the current limiter with three different core materials.

Field Distribution and Performance Analysis of a Passive Magnetic Fault-current Limiter under Transient Conditions

Abstract A magnetic fault-current limiter is a passive device consisting of a permanent magnet and saturable magnetic cores. It offers low inductance to the circuit under a normal operating condition and places a high inductance under a faulted condition. The current suppression capability of a steel core is higher than that of a ferrite-core fault-current limiter having the same dimension and topology. This article aims to investigate the transient performance of a fault-current limiter with steel and ferrite cores. Finite element analysis is used to observe the flux and mmf distribution inside the fault-current limiter under normal and faulted conditions.

Vibration control of a hybrid magnetic bearing using an adaptive sliding mode technique

This paper presents a consideration of the nonlinear modelling and vibration control of a hybrid magnetic bearing (HMB). The dynamics of the system are highly nonlinear in nature and exhibit parameter uncertainty. A sliding mode controller (SMC), well known for its robustness against parameter variation and external disturbance attenuation, was used, in the form of an adaptive sliding mode controller (ASMC), chosen because the ASMC operates in the absence of knowledge of the upper bounds of the system uncertainty, and its tracking performances are guaranteed. The HMB–ASMC system was simulated with varying system parameters and the performance of the controller is discussed. A laboratory prototype of the HMB system was built and experiments were carried out with the ASMC controller, which was found to offer acceptable vibration characteristics and disturbance attenuation.

Calculation of Passive Magnetic Force in a Radial Magnetic Bearing Using General Division Approach

This paper represents the force calculation in a radial passive magnetic bearing using Monte Carlo technique with general division approach (s-MC). The expression of magnetic force is obtained using magnetic surface charge density method which incurs a multidimensional integration with complicated integrand. This integration is solved using Monte Carlo technique with 1-division (1-MC) and 2-division (2-MC) approaches with a MATLAB programming. Analysis using established methods such as finite element method (FEM), semi-analytical method, and adaptive Monte Carlo (AMC) method has been carried out to support the proposed technique. Laboratory experiment has been conducted to validate the proposed method. 2-MC gives better result than 1-MC. The computation time of the proposed method is compared with the quadrature method, FEM and AMC. It is observed that the proposed method invites less computational burden than those methods as the algorithm adaptively traverses the domain for promising parts of the domain only, and all the elementary regions are not considered with equal importance.

An Improved Field Suppression System for SISFCL

Saturated iron-core superconducting fault current limiters (SISFCL) are becoming increasingly well known for their effective and reliable current limiting capabilities. The device is capable of producing very low impedance during normal operation and substantially high impedance during fault. Its ability of changing impedance can be attributed to the change of magnetic state of the ferromagnetic core of the device from saturation to unsaturation. The SISFCL employs a dc source to maintain the saturated state of the core for normal operation with the help of a superconducting coil. The high ac ampere turns during fault not only bring the core to unsaturation, but also cause alarmingly high voltage to develop across the dc source. Hence, the protection of the dc source is of great concern as the high voltage is capable of destroying the source and additionally, force the superconducting material to quench. In this paper, the SISFCL is analyzed using the finite element method and the field suppression method of dc source protection is discussed and shortcomings are pointed. The novelty of the paper lies in the use of shorted winding for the improved performance of the field suppression system. For the finite element method (FEM) analysis, the ANSYS Maxwell 2D software is utilized.

Jiles–Atherton Hysteresis Approach in Analyzing the Effect of Field Suppression in Saturated Iron-core Superconducting Fault Current Limiters

Abstract Saturated iron-core superconducting fault current limiters (SISFCL) are becoming more popular in the recent years due to their ability of reliable, effective and instantaneous fault limiting. With a superior performance than conventional current limiting methods, the SISFCL is finding its application in modern transmission lines and distribution system. In the SISFCL, the iron core is forced into saturation using a superconducting coil carrying DC current. During a fault in the system, the high fluxes set up in the AC coils interact with the DC flux, thereby reducing the flux density abruptly. This sudden change in the flux density induces a high voltage across the DC coil, which may damage the DC current source as well as the superconducting material. As a protective measure, a field suppressor unit is used that disconnects the DC supply following a fault. In this paper, a mathematical model of the SISFCL is developed considering hysteresis and the effects of the field suppressor unit have been analyzed. The paper also aims to highlight the effects on the performance of SISFCL with varying hysteresis loops of the core material.

Mathematical modeling and harmonic analysis of SISFCL

Purpose A saturated iron core superconducting fault current limiter (SISFCL) has an important role to play in the present-day power system, providing effective protection against electrical faults and thus ensuring an uninterrupted supply of electricity to the consumers. Previous mathematical models developed to describe the SISFCL use a simple flux density-magnetic field intensity curve representing the ferromagnetic core. As the magnetic state of the core affects the efficient working of the device, this paper aims to present a novel approach in the mathematical modeling of the device with the inclusion of hysteresis. Design/methodology/approach The Jiles–Atherton’s hysteresis model is utilized to develop the mathematical model of the limiter. The model is numerically solved using MATLAB. To support the validity of model, finite element model (FEM) with similar specifications was simulated. Findings Response of the limiter based on the developed mathematical model is in close agreement with the FEM simulations. To illustrate the effect of the hysteresis, the responses are compared by using three different hysteresis characteristics. Harmonic analysis is performed and comparison is carried out utilizing fast Fourier transform and continuous wavelet transform. It is observed that the core with narrower hysteresis characteristic not only produces a better current suppression but also creates a higher voltage drop across the DC source. It also injects more harmonics in the system under fault condition. Originality/value Inclusion of hysteresis in the mathematical model presents a more realistic approach in the transient analysis of the device. The paper provides an essential insight into the effect of the core hysteresis characteristic on the device performance.

Performance analysis of a three-phase SISFCL with the variation of circuit parameters using jiles atherton hysteresis model

In modern electrical power systems, Saturated Iron-Core Superconducting Fault Current Limiters (SISFCL) are becoming ever popular on account of their ability to instantaneously and reliably detect and limit the high magnitude fault current caused by short circuit faults. The SISFCL accomplishes this by altering the magnetic state of its ferromagnetic core material between saturation and unsaturation, thereby producing low impedance during normal operation and high impedance during faulted condition. In this paper, the mathematical model of a three-phase SISFCL is simulated using numerical methods in the MATLAB software environment. The effect of magnetic hysteresis of the core material is incorporated in the simulation via the Jiles-Atherton hysteresis model. The performance of the SISFCL is analysed against variations of the different circuit parameters namely, the fault resistance, DC bias current, number of turns of the AC and DC coil winding.

A comparative study between scalarization approach and Pareto approach for multi-objective optimization problem using Genetic Algorithm (MOGA) formulated based on superconducting fault current limiter

Optimal design of saturated iron-core superconducting fault current limiter (SISFCL) for satisfactory steady state and transient performance is very important. While designing the fault current limiter (FCL) utilizing Jiles-Atherton hysteresis model, it has been observed that a good fault current suppression ratio cannot be achieved without an appreciable voltage rise across the dc voltage source. Hence both objectives, suppressing the fault current and limiting the voltage rise across the dc voltage source are conflicting in nature and need to be optimized simultaneously. In this paper, two multi-objective optimization problem solving approach are compared. The first approach is scalarization whereas the second one is Pareto approach. A multi-objective GA algorithm for both the approaches is utilized to find the optimal solution for the satisfactory performance of SISFCL.

Performance Analysis of SISFCL with the Variation of Circuit Parameters using Jiles Atherton Hysteresis Model

Abstract In modern day power systems, fault current limiters (FCL) are used to provide protection from high fault currents in the event of electrical faults and thus help to deliver uninterrupted electric supply to the consumers. Several technologies of FCLs are available for practical usage. However, the saturated iron-core superconducting fault current limiter (SISFCL) has gained a lot of attention in recent years in view of its ability to offer very low impedance during normal operation and high impedance during faulted condition. Previous mathematical models defining the performance of the device employs a simple BH curve. But as the change in mathematical state of saturation and unsaturation is important for the operation of the device, the paper investigates the responses considering the effects of magnetic hysteresis utilising the Jiles Atherton hysteresis model. Further the performance of the device is analysed with the variations of different parameters viz., the fault resistance magnitude, DC bias current, number of turns of the AC winding and number of turns of the DC winding that portray the effectiveness of the parameters encouraging an optimal design of the limiter.