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Linear Circuits (linear + circuit)

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Selected Abstracts

Systematic unbalanced interharmonic interaction analysis with power constraints

EUROPEAN TRANSACTIONS ON ELECTRICAL POWER, Issue 1 2005
Jesús C. Contreras Sampayo
Abstract This paper presents a systematic technique to solve for the harmonic and interharmonic interaction between a power system and several harmonic sources. The technique can potentially analyze any power electronic source that can be modeled as a piece-wise linear circuit. Harmonic source data is input to the procedure using a standard lumped parameter description. Two test cases are presented. The first test case shows the interaction between a static var compensator (SVC) and an HVDC in unbalanced operating conditions. The second test case analyzes a complete current source variable speed drive connected to a distribution network. Both test cases include power constraints. Copyright © 2005 John Wiley & Sons, Ltd. [source]

A systematic method for the development of a three-phase transformer non-linear model

INTERNATIONAL JOURNAL OF CIRCUIT THEORY AND APPLICATIONS, Issue 8 2010
Andreas D. Theocharis
Abstract In this work, a novel three-phase transformer non-linear model is developed. The proposed model takes into account the magnetic core topology and the windings connections. The non-linear characteristic curve of the core material is introduced by its magnetization curve or by its hysteresis loop using the mathematical hysteresis model proposed by Tellinen or the macroscopic hysteresis model proposed by Jiles,Atherton. The eddy currents effects are included through non-linear resistors using Bertotti's work. The proposed model presents several advantages. An incremental linear circuit, having the same topology with the magnetic circuit of the core, is used in order to directly write the differential equations of the magnetic part of the transformer. The matrix Ld that describes the coupling between the windings of the transformer is systematically derived. The electrical equations of the transformer can be easily written for any possible connection of the primary and secondary windings using the unconnected windings equations and transformation matrices. The proposed methods for the calculation of the coupling between the windings, the representation of the eddy currents and the inclusion of the core material characteristic curve can be used to develop a transformer model appropriate for the EMTP/ATP-type programs. Copyright © 2009 John Wiley & Sons, Ltd. [source]

On stochastic modelling of linear circuits

INTERNATIONAL JOURNAL OF CIRCUIT THEORY AND APPLICATIONS, Issue 3 2010
Tarun Kumar Rawat
Abstract In this paper, the deterministic modelling of linear circuits is replaced by stochastic modelling by including variance in the parameters (resistance, inductance and capacitance). Our method is based on results from the theory of stochastic differential equations. This method is general in the following sense. Any electrical circuit that consists of resistances, inductances and capacitances can be modelled by ordinary differential equations, in which the parameters of the differential operators are the functions of circuit elements. The deterministic ordinary differential equation can be converted into a stochastic differential equation by adding noise to the input potential source and to the circuit elements. The noise added in the potential source is assumed to be a white noise and that added in the parameters is assumed to be a correlated process because these parameters change very slowly with time and hence must be modelled as a correlated process. In this paper, we model a series RLC circuit by using the proposed method. The stochastic differential equation that describes the concentration of charge in the capacitor of a series RLC circuit is solved. Numerical simulations in MATLAB are obtained using the Euler,Maruyama method. Copyright © 2008 John Wiley & Sons, Ltd. [source]

An algorithm for multiple fault diagnosis in analogue circuits

INTERNATIONAL JOURNAL OF CIRCUIT THEORY AND APPLICATIONS, Issue 6 2006
M. Tadeusiewicz
Abstract The paper deals with multiple fault diagnosis of analogue AC or DC circuits with limited accessible terminals for excitation and measurement and brings an algorithm for identificating faulty elements and evaluating their parameters. The main achievement is a method enabling us to efficiently identify faulty elements. For this purpose some testing equations are derived playing a key role in identification of possibly faulty elements which are next verified using a test of acceptance. The proposed approach is described in detail for double fault diagnosis. Also extension to triple fault diagnosis is given. Although the method pertains to linear circuits, some aspects of multiple fault diagnosis of non-linear circuits can be also performed using the small signal approach. Two numerical examples illustrate the proposed method and show its efficiency. Copyright © 2006 John Wiley & Sons, Ltd. [source]