The optimal passive filters to minimize voltage harmonic distortion at a load bus

This material is posted here with permission of the IEEE. Such permission of the IEEE does not in any way imply IEEE endorsement of any of Brunel University's products or services. Internal or personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution must be obtained from the IEEE by writing to [email protected]. Copyright @ 2005 IEEEA method is presented for finding the optimum fixed inductance-capacitance combination to minimize voltage harmonic distortion at a load bus where it is desired to maintain the displacement power factor at a desired level constraining the compensator values, which would create resonance conditions, and the manufacturers' standard values for power shunt capacitors according to IEEE Standard 18-2002. A comparison study of using the constraint, holding either the displacement power factor or the power factor at a desired value, is done. Finally, the contribution of the newly developed method is demonstrated in six examples taken from existing publications

Capacitive compensation at nonsinsoidal buses based on IEEE Std. 18-1992

This material is posted here with permission of the IEEE. Such permission of the IEEE does not in any way imply IEEE endorsement of any of Brunel University's products or services. Internal or personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution must be obtained from the IEEE by writing to [email protected]. Copyright @ 2003 IEEEThis letter presents a proposed method for finding the optimum fixed compensating capacitor to minimize the voltage harmonic distortion at a load bus while holding the power factor at a desired value and constraining the nameplate kiloVAr of the compensating capacitor, its rated voltage RMS, and its rated current RMS as constraints according to IEEE Std. 18-1992. Also, the values of the compensating capacitor, which would create resonant conditions, would be omitted from the solution. Finally, the contribution of the newly developed method is demonstrated in an example taken from previous publications

Voltage harmonic reduction for randomly time-varying source characteristics and voltage harmonics

This material is posted here with permission of the IEEE. Such permission of the IEEE does not in any way imply IEEE endorsement of any of Brunel University's products or services. Internal or personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution must be obtained from the IEEE by writing to [email protected]. Copyright @ 2006 IEEEPotential applications of probabilistic modeling of current and voltage harmonics concern many aspects of power system engineering as accurate prediction of power system harmonic behavior provides important information to utility companies and equipment designers. In this paper, a method of reducing the expected value of the total voltage harmonic distortion for a specified range of source impedance values at different buses by using LC compensators, where it is desired to maintain a given power factor at a specified value, is presented. The criterion is based on mean value estimation of source and load characteristics, which are enabled by sampling measurements performed on the examined electrical plant as well as statistical analysis

Cost-effective applications of power factor correction for nonlinear loads

This material is posted here with permission of the IEEE. Such permission of the IEEE does not in any way imply IEEE endorsement of any of Brunel University's products or services. Internal or personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution must be obtained from the IEEE by writing to [email protected]. Copyright @ 2005 IEEEThe objective of this paper is to propose a new approach for designing passive LC compensators by using the penalty function method as an optimization tool. The performance of the cost-effective passive LC compensator for a constant load depends on the appropriate inductor and capacitor selection. Several design methods are reviewed and a novel design methodology is proposed in this paper. By using the proposed method, the designer can quickly find appropriate parameter values to meet the desired circuit performance. Simulated results show that an appropriate combination of the inductor and capacitor selected by the proposed method can meet the desired power-quality requirement. Different cases of design examples are shown in this paper to verify the performance of the proposed design methodology

Cinematic experience, film space, and the child’s world

This is the full published version of this article as first published in the Canadian Journal of Film Studies, 2010, 19 (2) 82-98. http://www.filmstudies.ca/journal/cjfs/archives/articles/kuhn_cinematic_experience_film_space_childs_worl

Comparison of different optimization criteria for optimal sizing of hybrid active power filters parameters

Praise Worthy Prize granted a permission for Brunel University London to archive this article in BURA.Harmonic distortion in power systems has increased considerably due to the increasing use of nonlinear loads in industrial firms and elsewhere. This distortion can give rise to overheating in all sectors of the power system, leading to reduced efficiency, reliability, operational life and sometimes failure. This article seeks to propose a new methodology for the optimal sizing of hybrid active power filter (HPF) parameters in order to overcome the difficulties in hybrid power filters design when estimating the preliminary feasible values of the parameters. Sequential Quadratic Programming based on FORTRAN subroutines is used to find out the planned filter size in two different optimization criteria depending on design concerns. The first criterion is to minimize the total voltage harmonic distortion. The second one is to maximize the load power factor, while taking into account compliance with IEEE standard 519-1992 limits for the total voltage harmonic distortion and the power factor.The effectiveness of the proposed filter is discussed using four exemplary case

Hypersonic aerodynamics on thin bodies with interaction and upstream influence

In the fundamental configuration studied here, a steady hypersonic free stream flows over a thin sharp aligned airfoil or flat plate with a leading-edge shock wave, and the flow field in the shock layer (containing a viscous and an inviscid layer) is steady laminar and two-dimensional, for a perfect gas without real and high-temperature gas effects. The viscous and inviscid layers are analysed and computed simultaneously in the region from the leading edge to the trailing edge, including the upstream-influence effect present, to determine the interactive flow throughout the shock layer and the positions of the shock wave and the boundary-layer edge, where matching is required. Further theoretical analysis of the shock layer helps to explain the computational results, including the nonlinear breakdown possible when forward marching against enhanced upstream influence, for example as the wall enthalpy increases towards its insulated value. Then the viscous layer is computed by sweeping methods, for higher values of wall enthalpies, to prevent this nonlinear breakdown for airfoils including the flat plate. Thin airfoils in hypersonic viscous flow are treated, for higher values of the wall enthalpies and with the upstream-influence effect, as are hypersonic inviscid flows, by modifying the computational methods used for the flat plate. Also, the behaviour of the upstream influence for bodies of relatively large thickness, and under wall velocity slip and enthalpy jump for flat plates, is discussed briefly from a theoretical point of view. Subsequent to the present work, computations based on the Navier–Stokes and on the parabolized Navier–Stokes equations have yielded excellent and good agreement respectively with the present predictions for large Mach and Reynolds numbers

Calamares de la familia Onychoteuthidae Gray, 1847 en el Océano Pacífico suroriental

Indexación: Web of ScienceHooked squids (Family Onychoteuthidae Gray, 1847) inhabit all oceans of the world except the Arctic. This family is currently comprised of 25 species belonging to seven genera. In the southeastern Pacific Ocean, approximately five onychoteuthid species have been previously identified, but true identity of these taxa is uncertain. We reviewed museum collections, from Chile, United States and New Zealand, and literature to elucidate the presence of hooked squids in the southeastern Pacific Ocean. The present status of the Onychoteuthidae from the southeastern Pacific only includes four species: Onychoteuthis aequimanus, Onykia ingens, Onykia robsoni, and Kondakovia nigmatullini.RESUMEN. Los calamares ganchudos (Familia Onychoteuthidae Gray, 1847) habitan en todos los océanos excepto en el Ártico. Esta familia está compuesta actualmente de 25 especies pertenecientes a siete géneros. En el Océano Pacífico suroriental, aproximadamente cinco especies de Onychoteuthidae han sido identificadas previamente, pero su estatus taxonómico es incierto. Se revisaron las colecciones de museos de Chile, Estados Unidos y Nueva Zelanda, y la literatura para dilucidar la presencia de calamares con ganchos en el Pacífico suroriental. El estado actual de la familia Onychoteuthidae en esta área incluye solo cuatro especies: Onychoteuthis aequimanus, Onykia ingens, Onykia robsoni y Kondakovia nigmatullini.http://www.lajar.cl/pdf/imar/v44n2/Art%C3%ADculo_44_2_23.pd

Adaptive quadrature by expansion for layer potential evaluation in two dimensions

When solving partial differential equations using boundary integral equation methods, accurate evaluation of singular and nearly singular integrals in layer potentials is crucial. A recent scheme for this is quadrature by expansion (QBX), which solves the problem by locally approximating the potential using a local expansion centered at some distance from the source boundary. In this paper we introduce an extension of the QBX scheme in 2D denoted AQBX - adaptive quadrature by expansion - which combines QBX with an algorithm for automated selection of parameters, based on a target error tolerance. A key component in this algorithm is the ability to accurately estimate the numerical errors in the coefficients of the expansion. Combining previous results for flat panels with a procedure for taking the panel shape into account, we derive such error estimates for arbitrarily shaped boundaries in 2D that are discretized using panel-based Gauss-Legendre quadrature. Applying our scheme to numerical solutions of Dirichlet problems for the Laplace and Helmholtz equations, and also for solving these equations, we find that the scheme is able to satisfy a given target tolerance to within an order of magnitude, making it useful for practical applications. This represents a significant simplification over the original QBX algorithm, in which choosing a good set of parameters can be hard