Design and performance analysis of a single phase PWM inverter

IEEJ Transactions on Electrical and Electronic Engineering, 2011

Fault current limiters (FCLs) are expected to play an important role in protection of future power grids. By inserting a limiting impedance in series with a line, they limit the increasing levels of the fault currents to acceptable values. Inductive FCLs based on core-saturation effect are particularly interesting due to their inherent reaction on a fault. However, some challenges are to be solved: too large amount of required material and induced over-voltage across the DC winding that is used to drive the core into saturation. This paper introduces a new configuration of the inductive FCLs, where the amount of the required material is reduced considerably and the induced over-voltage across the DC winding is decreased. The amount of magnetic material is reduced by employment of one core per-phase instead of two. The middle leg of the three-leg core is used as a shunt path for the AC flux. It enables a gap insertion in the AC magnetic circuit without influencing the DC magnetic circuit, i.e. the amount of DC winding material. Thus, a smaller core (less magnetic material) can be used for the same power level. Results obtained from the lab prototype match very well the one from simulations. 

Transformers Magazine, 2021

The energy transition is a necessity to satisfy the consumption and impact of humanity on the environment. Therefore, to fulfill this demand, renewable energies and microgrids have been developed. Consequently, fault current levels have overcome the circuit breaker capacity in many substations over the years. Then, the development of the fault current limiters has become a potential solution to solve this problem. The literature has presented several topologies over the past decades.

Increasing electrical energy consumption and associated power grid expansion tend to increase the level of the fault currents in power systems. Maintaining proper functioning of the grid requires fault currents to be at an acceptable level using appropriate fault current limiting techniques. Most of the fault current limiter devices work in a saturated core region during normal operation mode. Since the continuous saturation core also requires continuous energy supply, the use of the cores that operate at low initial permeability region is a suitable candidate with no power consumption. For this purpose, the potential use of the SAE 1020 low carbon steel in the fault current limiter is investigated. The design simulation is carried out in terms of required shape, dimensions and parameters by using finite element analysis. The dimension of the fault current limiter is optimised by introducing air gaps into the core, while keeping the performance of the fault current limiter device unchanged. The simulation results indicate that the proposed design with air gaps still has a better current limiting performance compared to the coil with pure air core. Reducing the dimensions of the device is achievable in the expense of its performance.

IEEE Transactions on Applied Superconductivity, 2015

Inductive fault current limiters, such as saturated cores topology, have been considered as an enabling technology for the advent of modern power grids. Thereby, several full-scale prototypes have been developed in recent years aiming, e.g., supporting increased penetration of dispersed generation, mostly from renewable sources. For the advent of these devices and technology, the development of straightforward design tools that allow simulating them in electrical power grids with different voltage ratings and characteristics is required. In this paper, a methodology for simulating the behavior of saturated cores limiters is presented as an alternative to techniques based on finite elements methods (FEM), thereby dramatically reducing computation time. This methodology is based on characteristic parameters of those limiters and is compared with FEM simulations. Experimental measurements in a laboratory scale prototype are also carried out to validate the proposed methodology.

Physics Procedia, 2012

Inductive superconducting fault current limiters have already demonstrated their technical viability in electrical networks. Its architecture and robustness make them potentially adequate for distribution networks, and this type of devices is considered as an enabling technology for the advent of embedded generation with renewable energy sources. In order to promote the growth and maturity of these superconducting technologies, fast design tools must be developed, allowing simulating devices with different materials in grids with diverse characteristics. This work presents advances in the development of such tool, which, at present stage, is an effective alternative to software simulations by finite elements methods, reducing dramatically computation time. The algorithms are now compared with experimental results from a laboratory scale prototype, showing the need to refine them.

Electric Power Systems Research, 2020

Due to increasing demand for electrical power in nowadays power grids, inevitably, the short circuit current will be increased. The power system faults are categorized in two groups: first, the symmetrical three-phase faults which generally caused by the carelessness of operating personnel and second, unsymmetrical faults which are very contingent in transmission system. The latter is the principal aim of this paper. Fault Current Limiter (FCL) is a device to limit the fault current. Conventional core-based FCLs have some drawbacks such as: (1) core losses and heat generation caused by permanent operation in saturation region under normal condition, (2) requiring two cores per phase that makes FCL bulky and (3) extra cost, losses as well as reducing reliability by using external DC source. This paper proposes a novel method for limiting unsymmetrical faults current. The suggested design employs a common unsaturated core for all three phases in order to limit of the first cycle of fault current automatically and without fast detection systems; employment of thyristor controlled braking resistor (TCBR) is considered for eliminating the imposed over-voltages on faultless lines and further limitation of fault current. Simulations and design aspects of implementing practical issues show the validity of the proposal.

Electrical, Control and Communication Engineering, 2014

Magnetic shielding inductive fault current limiters with high temperature superconducting tapes are considered as emerging devices that provide technology for the advent of modern power grids. The development of such limiters requires magnetic iron cores and leads to several design challenges regarding the constitutive parts of the limiter, namely the primary and secondary windings. Preliminary tests in a laboratory scale prototype have been carried out considering an assembly designed for simplicity in which the optimization of the magnetic coupling between the primary and secondary was not the main focus. This work addresses the design configuration of an inductive current limiter prototype regarding the assembly of the primary and secondary windings in the core. The prototype is based on a closed magnetic core wound by a primary, built from a normal electric conductor, and a short-circuited secondary, built from first generation superconducting tape. Four different design configu...

IEEE Transactions on Magnetics, 2020

In this article, a novel concept of an inductive, saturated-core fault-current limiter (FCL) design is presented, capable of limiting three-phase faults. The design is based on high-remanence permanent magnets for biasing high-saturation electrical steel cores, thus minimizing the device volume, dimensions, and cost and allowing a relatively easy assembly process due to the magnetic symmetry of the model. By implementing a three-phase design in a single device, we harness the full potential of each magnet, substantially reducing the required material for achieving negligible losses during nominal operation while increasing current limiting during faults. A laboratory-scale, low-voltage prototype has been built and tested to prove the feasibility of the new concept, suggesting that upscaling to higher voltage devices is plausible. Extensive simulations, using finite-element analysis, have yielded insight into several measured phenomena, including a unique phase-coupling effect experienced during three-phase fault measurements.

Superconductor Science and Technology, 2010

The paper deals with basic designs of a fault current limiter of the transformer type which differ each other by the mutual location of a primary winding and a superconducting short-circuited cylinder. Theoretical study of the main parameters of the different designs is performed in the framework of the critical state model and shows that the most effective is a design in which the primary winding is divided to two sections with equal turn numbers. The sections are placed inside and outside of the cylinder and connected in series. Such arrangement of the windings leads to a substantial reduction of AC losses in the superconducting cylinder, an increase of the activation current and a decrease of the inductive reactance in the normal regime of a protected circuit. The experimental results obtained on the laboratory model with a BSSCO cylinder confirm the theoretical predictions. (Some figures in this article are in color only in the electronic version) Keywords: superconducting current limiter, design, AC losses c b c m J H H J

The Journal of Engineering Research [TJER], 2021

This paper proposes an improvement for the dynamic performance of presaturated stacked permanent magnet biased three-phase fault current limiter (PMFCL) through COMSOL finite element simulation. The nonlinear demagnetization behavior of the permanent magnet, especially in the upper part of the B-H curve with negative magnetic field intensity, has been modelled through the Jiles-Atherton method. This enables a realistic representation of the PMFCL dynamic behavior throughout its entire operations of pre-fault, fault and fault removal, respectively. The experimental measurements have been considered to validate the trends of the simulation outcomes during the entire operation of PMFCL. Extensive finite element simulation shows that the stacked design of PMFCL can increase the capability of fault current limiting with proper selection of the number and arrangement of the AC coils around the iron core (soft magnet). Results reveal that the division of AC coils into series differential c...