Systematic higher order nonlinear analysis of power systems operating under p…

Abstract In this paper, the modal series method is revisited and an extension on the method to include higher order terms is proposed. This proposal is based on the introduction of the multidimensional Laplace transform and association of variables theorems to deduce the analytical closed-form solution when it is applied to the analysis of a nonlinear power system model. The method is systema…

Single point bearing fault diagnosis using simplified frequency model

Abstract The time synchronous averaging (TSA) is a wellknown technique used for early detection of bearing failure in electrical machines. This method is very efficient if the characteristic default frequency is perfectly known. In this article, a reduced frequency model, derived from ESPRIT algorithm, is used to provide a very accurate estimation of the fault frequency. The precision obtaine…

Simplified model predictive current control without mechanical sensors for va…

Abstract This paper proposes a simplified finite-controlset model predictive current control (FCS-MPCC) without mechanical sensors for permanent-magnet synchronous generators (PMSGs) in variable-speed wind energy conversion systems. The procedure of selecting the best switching vector is optimized by computing the reference voltage vector (VV) directly from the reference current. Subsequently…

Optimal reactive-power dispatch using differential search algorithm

Abstract Optimal reactive-power dispatch (ORPD) is one of the most difficult optimization problems regarding to power-system operation which is heavily related to system stability. To overcome ORPD problem, in general, the total real-power loss is reduced by determining the power-system control parameters, such as generator voltages, tap ratios of tap-changer transformers, and compensated rea…

Optimal C-type filter for harmonics mitigation and resonance damping in indus…

Abstract Single-tuned passive filters offer reasonable mitigation for harmonic distortion at a specific harmonic frequency with a high filtering percentage, but resonance hazards exist. Traditional damped filters offer high-pass filtering for the high-frequency range, but suffer from extra ohmic losses. C-type filters may operate in a manner similar to the tuned filters with lowdamping losses…

New procedure for harmonics estimation based on Hilbert transformation

Abstract The paper suggests a new procedure for the estimation of the parameters (amplitude and phase) for a complex periodic signal, based on the concept of analytic signal (AS). Starting from the supposition that the signal fundamental frequency has been estimated in advance at an independent stage, new analytical relations are derived for fast calculation of the unknown parameters, entail…

Operation of five-phase induction motor after loss of one phase of feeding so…

Abstract The paper deals with the influence of a loss of one phase of a feeding source on the properties of a five-phase induction machine. The attention is paid to the waveforms of the currents in individual stator phases, the increase in torque pulsations and the decrease of speed in emergency operation after the disconnection of a faulty phase of the source. Machines in star, pentagon and …

Optimization of soil moisture sensor placement for a PV-powered drip irrigati…

Abstract The efficiency and installation costs of solarpowered drip irrigation systems depend on not only the efficiencies of the electrical motor, its driver, and the pump, but also the efficient usage of irrigation water. In this study, the initial installation costs and energy consumption of photovoltaic irrigation systems were decreased by obtaining the soil moisture level as a reference …

Neural network based diagnosis of partial discharge defects patterns at XLPE …

Abstract The application of the XLPE cable under DC stress is now being considered as one of the promising tool for enlarging the limited transmission capacity of the traditional electric power cable due to the several technical advantages. Therefore, many research institutes are trying to improve the performance by carrying out experimental investigations related to the reliability of the ca…

Multi-objective optimization of passive filters in industrial power systems

Abstract The formulations employed to the optimization of passive filters can be classified as formulations of a single objective or formulations with multiple objectives. The single-objective formulations normally are devoted to determine the filters of lowest cost that assure the compliance with the power quality standards, while in the multi-objective approaches are added other goals that …

Mathematical reconsideration of number of variables in power flow computation

Abstract It has been conventionally believed that there exist 4n variables P, Q, V, θ for an n-bus system in the power flow computation, while we have 2n power flow equations. In this article, the authors argue that the number of variables in an nbus system is not 4n but 4n−1, hence the power flowsolution can be obtained without specifying the reference angle of the slack bus.We then deliv…

Loss of excitation of SMIB power system equipped with high photovoltaic penet…

Abstract The effect of high photovoltaic (PV) penetration with constant injected voltage on the loss of excitation phenomenon of single machine infinite bus power system with two transmission lines has been investigated. The PV modules are integrated to the power system at the same bus of the synchronous generator via DC–DC buck–boost switch mode converter, three-phase DC–AC switch mode…

Influence of volume effect on electrical discharge initiation in mineral oil …

Abstract This article deals with the problem of electrical discharge initiation in mineral oil in the setup of insulated electrodes. The results of laboratory experimental studies were collated with the results of the numerical calculations of electrical field stress. Both kinds of the research methods were applied to analyze the two model electrode setups immersed in mineral oil: setup with …

Improving the energy efficiency of induction cooking 2

Abstract In the October 2009 issue of this Journal, we introduced a special pot type, which could improve the energy efficiency of induction cooking, make the boiling process faster and the cooking more comfortable. The dissipated power in the new pot was significantly higher than in the traditional ones at any inductor current. In this paper we show another pot type with similar advantages, …

Failure mode and effects analysis of power quality issues and their influence…

Abstract Today electronic devices require a power supply without any variation or disturbance. Nevertheless, electrical variations presented in power lines are more frequent and powerful. The consequences of poor power quality devices. Thus, in this study, an FMEA is presented to know which electrical variation has more effect on the reliability of electronic devices. The analysis was perform…

Energy storage system location selection for smart grid applications on distr…

Abstract Every day, the evaluation of classical distribution networks (DNs) to smart grids (SGs) has become a necessity, and renewable energy sources (RESs) are an important part for smart grids. One of the most significant problems for RESs is the sustainability of energy, because the raw material storage is not possible for renewable energy sources as photovoltaic (PV), wind, etc. Therefore…

Analysis of statistical features based on start-up current envelope for broke…

Abstract Line start-permanent magnet synchronous motor (LS-PMSM) is one of the modern high efficiency motor introduced to the industry, recently. Like other types of electrical machines, various failures may happen in LS-PMSM during its life time. Among different failures which may occur in the motors with squirrel cage rotor, rotor fault (broken rotor bar) is the most significant one. This p…

Design, implementation, and verification of computer interactive parallel con…

Abstract This study presents an advanced computer interactive system for automatic parallel connection of synchronous generators and load sharing control between them. Because of its high operation speed and precision, a dsPIC microcontroller has been used in the study to control the conditions for paralleling and then to realize the connection, to transfer the real time data among the contro…

Effect of combined stator winding on reduction of higher spatial harmonics in…

Abstract The paper introduces the possibility to eliminate certain groups of spatial harmonics of the current layer, magnetic flux density in the air gap and flux in the yoke of the induction machine with the aim to increase the efficiency. The content of higher spatial harmonics is reduced by means of the so-called combined winding. It is shownhowthis winding must be arranged in stator slots…

Effect of armature reaction on the core losses of the permanent magnet synchr…

Abstract Traditionally, the core losses of permanent magnet synchronous motors are assumed to vary as a function of rotational speed and the supply voltage. In this paper, the effect of armature reaction on the core losses under constant speed and stator voltage is studied. The load angle of the machine is varied, and the core losses are determined using the finite element analysis.To explain…

Dynamic performance of wind turbine conversion system using PMSG-based wind s…

Abstract This paper presents an experimental investigation of a small-scale wind turbine conversion system (WTCS), using wind power simulator based on a permanent magnet type synchronous generator (PMSG) which is directly coupled to a servomotor to emulate the WTCS. The wind power simulator is either speed or torque controlled in which propose a “wind shaft”, to verify the dynamic and sta…

Development of an optical fiber-based interferometer for strain measurements …

Abstract In this paper, an extrinsic Fabry–Perot interferometer (EFPI) has been demonstrated for strain measurements. A monochromatic light source with a wavelength of 1310 nm is propagated into a single-mode fiber and then passed through the sensing arm. Approximately, 4 % of the beam is reflected off at the fiber end generating the “reference signal”, while the rest is next transmitte…

Comparison performance between sliding mode control and nonlinear control, ap…

Abstract A squirrel cage induction motor has been the workhorse in industry for variable speed applications in a wide power range that covers from fractional horsepower to multi megawatts. But the control and estimation of ac drives in general are considerably more complex than those of dc drives. The advent of vector control techniques has partially solved induction motor control problems. H…

Analytical calculation method for the non-linear characteristic of ferrite-co…

Abstract Magnetic devices are essential components in the field of power electronics. Exploiting the non-linear behavior of inductors and transformers offers the great merit of increasing the performance of switch mode power supplies. For instance, the light-load efficiency of a buck voltage regulator can be improved by using a non-linear inductor with stepped air gap. Moreover, non-linear ch…

Artificial neural-network-based fault location for power distribution lines u…

Abstract This study presents an artificial neural-network (ANN)-based digital fault classification and location algorithm for medium voltage (MV) overhead power distribution lines with load taps and embedded remote-end source. The algorithm utilizes frequency spectra of voltage and current samples which are recorded by the digital relay at the substation. In the algorithm, to extract useful i…

Analysis of transient-to-island mode of power electronic interface with conve…

Abstract Distributed generation (DG) is predicted to play an increasingly important role in the future power system. DGs, however, can provoke technical problems when they are added to the existing system. An islanding is one of those problems while using DGs. During that mode, the power electronic interface of DGs has both roles of keeping the point of common coupling’s voltage within a re…

A novel single-stage single-phase buck–boost inverter

Abstract In this paper, a novel single-stage single-phase buck–boost inverter design is presented. Depending on the duty ratio, the output voltage of the proposed inverter can be lower or higher than the DC input one. Similar to the conventional voltage source inverter, the proposed inverter includes four power electronic switches without the need for any extra switches. All the inverter fo…

A model validation scale based on multiple indices

Abstract Validation of an estimated model is not a trivial task because it depends on the purpose of the model, which usually defines the most important features of the model. Thus, in a validation process, the use of diverse tools that exploit different domains is recommended. Here, with this aim, a scale for model validation is proposed that combines the Normalized Root Mean Square Error …

Analytical and FEM approach to reduce the cogging torque in in-wheel motors

In-wheel direct drive motors are placed inside drive wheels of electric vehicles and have to deliver large torque without any mechanical gear. Most often these machines are of synchronous type with permanent magnets and large pole-pair number. As a consequence of high peak torque, both cogging torque and torque ripple are increased if no measures are taken to decrease them. The vibrations due t…

BFA optimization for voltage and frequency control of a stand-alone wind gene…

A developed control strategy for autonomous wind generation unit is presented. Optimization techniques based on bacteria foraging algorithm and genetic algorithms are used to tune the proposed control parameters. The proposed system mainly consists of induction generator driven by wind turbine, synchronous machine, consumer load, discrete dump load, and gate turn-off thyristor-based power elec…

Running up and pulling into step of PM line-start motors with surface-mounted…

Permanent magnet (PM) synchronous motors with starting cage, already developed in the 1960s for variable-speed textile drives, become increasingly important as energy-efficient PM line-start motors. Differing from the standard design with integrated magnets, a rotor design with surface-mounted magnets is presented. In the planning and design phase of drives with PM line-start motors, the simul…

Wind-driven stand-alone six-phase self-excited induction generator transients…

This paper present the transient performance of an isolated six-phase self-excited induction generator (SPSEIG) driven by a fixed-pitch wind turbine. The approach is based on a wind-turbine model, SPSEIG model and detailed transient behaviour of an SPSEIG for stand-alone power generation, when subjected to sudden switching of balanced/unbalanced R, RL and RLC load for both threephase winding se…

Wind turbine gearbox fault diagnosis based on symmetrical components and freq…

The region of Adrar in Algeria is the windiest in the country; it is for this reason the lectricity and gas company “Sonelgaz” has placed a wind farm of about 10MW.Since it is a Saharan region, the wind is sandy, rich in silica that can damage the teeth of wind gearbox. The present work proposes a method which can make an early diagnosis of the broken tooth and its location in the gearbox, …

The significance of frequency-dependent overhead lines for the calculation of…

In this paper the short-circuit current of overhead transmission lines is analyzed at a short circuit in an HVDC transmission network. The analysis focuses solely on the current contribution of the transmission line at a line-to-earth or a line-to-line short circuit. In this context it is shown which impedance is effective at the corresponding fault case. Special attention is given to the frequ…

VSC-HVDC system optimized PI controllers using bacterial foraging algorithm

The strategy of control for high-voltage direct current system on voltage-source converter HSC-HVDC is based on an important element which is PI controller. Because of its simple structure and strong robustness in a wide range of serving conditions, it has been used in the control system in the last few years. Therefore, it is important for the VSC-HVDC system permanent regime to choose proper …

The implementation of capital budgeting analysis for distributed generation a…

For the last 7 years, the Republic of Croatiahas been witnessing a sudden increase of distributed en Argyresources connecting to its power system. However, a significant problem is how to find the financial equilibrium whichwill satisfy the independent power producers on one side and the Distribution system operator on the other. In this paper, the authors discuss the capital budgeting analysis…

Self-resonant frequencies of air-core single-layer solenoid coils calculated …

Single-layer air-core solenoid coils are importantcomponents in many fields of electrical engineering, such as, high- frequency applications, air-core transformers, inductive sensor sand wirelesspower transfer.The calculationo fits self-resonant frequencies is of primary interest in many different situations. In these components, the validity of lumpe delement model Discritical,since even for r…

Reactive power and voltage control in grid-connected wind farms: an online o…

This paper presents the application of an online optimization based fast model predictive control scheme to grid-connected wind farms for reactive power and voltage control. A linear prediction model of the network was used to predict the behavior of the system for a certain prediction horizon, while a modified quadratic programming problem was used for the optimization process. The proposed co…

Power transfer capability enhancement with multitype FACTS controllers using …

In this paper, a new hybrid particle swarm optimization (HPSO) based on particle swarm optimization (PSO), evolutionary programming (EP), tabu search (TS), and simulated annealing (SA) is proposed. The aim of merging is to determine the optimal allocation of multi-type flexible AC transmission system (FACTS) controllers for simultaneously maximizing the power transfer capability of power transa…

Phase shift of the current under a single-phase short-circuit in the stator w…

An equivalent model of a faulty turbogenerator under a single-phase short-circuit in the stator winding is presented. The model is based on modified voltage–current equations for the positive-sequence component of the shortcircuit current that takes into account the mutual spatial displacement of particular part of the faulty stator winding, the rotor magnetic asymmetry and the impact of the…

Particle swarm optimization of an extended Kalman filter for speed and rotor …

A novel method based on a combination of the extended Kalman filter with particle swarm optimization (PSO) to estimate the speed and rotor flux of an induction motor drive is presented. The proposed method will be performed in two steps. As a first step, the covariance matrices of state noise and measurement noise will be optimized in an off-line manner by the PSO algorithm. As a second step, t…

Numerical analysis of local hot-spot temperatures in transformer windings by …

This paper deals with the thermal characteristics of traditional mineral oil and alternative dielectric fluids. Candidates of alternative dielectric fluids used in the transformer were silicon oil, HMWH, synthetic ester and natural ester. In this study, the transformer which uses synthetic ester and natural ester was focused. 3 ph, 66 kV, 16.5 MVA power transformer and 3 ph, 22 kV, 2.3 MVA dist…

Multi-tank resonant topologies as key design factors for reliability improvem…

To improve electrical properties of power converters suited for power energy systems, the paper deals with investigation of novel multi-tank resonant topologies. First, standard LLC converter is analyzed, as well as mathematical model during operation intervals is developed. After it, modifications of LLC converter for better dynamic behavior during start-up and short-circuit operation are desc…

Mixed resistive unbalance and winding inter-turn faults model of permanent ma…

This work analyzes the behavior of surfacemounted permanent magnet synchronous motors (SPMSMs) operating under stator faults. The studied faults are resistive unbalance and winding inter-turn short circuits, which may lead to unbalanced conditions of the motor. Both faults may reduce motor efficiency and performance and produce premature ageing. Thiswork develops an analytical model of the mot…

Implementation of PWM control strategy for torque ripples reduction in brushl…

The generated torque ripples from the BLDC motor is the main issue that affects the drive performance of the BLDC drive system. In this paper, a new switching technique to minimize the torque ripples due to current commutation is proposed. The presented scheme has been implemented using a commercial and low-cost mid-range PIC microcontroller to generate the modified pulse width modulation (PWM)…

Implementation of digital FCS-MP controller for a three-phase inverter

Edisi

(2015) 97:25–34

ISBN/ISSN

DOI 10.1007/s00202-0

Deskripsi Fisik

Electr Eng (2015) 97:25–34

Judul Seri

ELECTRICAL ENGINEERING

No. Panggil

-

Generalized predictive control robust for position control of induction motor…

This paper presents the study and implementation of a different field-oriented control strategy using a generalized predictive control (GPC) technique applied to the mechanic position loop aiming to obtain a system that acts in the fractional horsepower motor driver running at near zero frequency. The position and speed loops were identified to verify the system behavior and, from the model fou…

High performance DTC of induction motor drives over a wide speed range

This paper presents an effective scheme to minimize the torque ripples for direct torque control (DTC) of induction motor drives. The switching strategy compares the torque error from a PI torque controller with two triangular waveforms, and then produces a constant switching frequency, which is determined by the frequency of the triangular waveforms and is almost independent of the speed. The …

Estimating stray current interference from DC traction lines on buried pipeli…

The paper presents a non-deterministic approach to the study of stray current effects generated by direct current railway or tramway lines on buried pipelines which are located in the nearby area. The potential shift induced (via conductive coupling) on the latter ones by the stray current dispersed in the soil is evaluated by means of a suitable equivalent circuit combined with a Monte Carlo p…

Effect of higher spatial harmonics on properties of six-phase induction machi…

The paper deals with analysis of the situation in a six-phase induction machine. For this purpose, the method of space vectors is used. It is shown that higher space harmonic waves of current layer, flux density and flux in the stator yoke have to be considered especially when the stator is fed by unbalanced voltages. The equations of a six-phase induction machine are derived and relation betwe…