s-domain analysis of electromagnetic transients on nonuniform lines

Saied, M.M.; Al-Fuhaid, A.S.; El-Shandwily, M.E.

doi:10.1109/61.103703

Cited by 33 publications

(23 citation statements)

References 13 publications

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“…stage of sophistication including transformer modelling and capability to consider non-uniform lines [16]. Many of the Laplace transform applications have been for the case of fast transients (i.e., electromagnetic analysis of surges and lighting strokes).…”

Section: Connection With Laplace Transform Methodsmentioning

confidence: 99%

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A new method for the calculation of subtransmission and distribution system transients based on the FFT

Heydt

1989

IEEE Trans. Power Delivery

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This paper presents an interesting method for the calculation of bus voltage transients in an electric power system. The method is specifically intended for application to distribution and subtransniission networks. The transient bus voltages are calculated during the application of large industrial loads. In this sense, the calculation is a power quality assessment. In particular, the case of load currents which are electronically switched may be analyzed. The essence of the method is the Fourier transform of Ohm's law. The fast Fourier transform is used in order to give computational efficiency. An interesting method for obtaining the Fourier transform of the bus transfer impedance, Z,j(w), is developed from the theory of parallel n-port networks. Two approximations are found for the calculation of this transfer impedance and one of these is found to be applicable to the cited problem. Examples are used to illustrate the calculation of bus voltage transients and harmonic content. Although the latter is not a transient, harmonic voltages may be calculated by the proposed method under certain circumstances. The main application illustrated is that of a transient which has dynamics which occur in a time interval of similar order as the period of the power frequency (i.e., 1/60 sec for a 60 Hz system). With the advent of power electronic switches, this type of transient is a serious reality at distribution power levels. The frequency response of an electrical networkConsider a multi-port electric network of n+l busses with voltages at each bus measured from a given reference bus as vl(t), vz(t), . * ,vn(t). Also consider injection currents at the busses with return path through the reference bus. These currents are il(t), i2(t), * ,in(t). Under most circumstances of practical interest, these voltages and currents possess a two-sided Fourier transform, for example,Consider further that the electrical network is decomposed into two networks labeled SE and SH which are characterized as follows: the SE network contains only resistances and inductances and therefore this network is modelled as W -W 89 WM 101-7 PWRD by the IEEE Transmission and Distribution Committee of the IEEE Power Engineering Society f o r presentation a t the IEEE/PES A paper recommended and approvedwhere VSE(t) and iSE(t) are n-dimensional vectors of the bus voltages and currents using one system bus as a reference. Similarly, let the SH network contain only conductances and capacitances. The SH network is modelled asThe terms RSE, LSE, GSH, and CSH are n by n matrices which exist and are non-singular when the SE and SH networks are connected. The reference bus must be connected to each system bus. The Fourier transform of Equations (1) and (2) areFrom these equations one collects terms and recognizes familiar expressions,vSH(w) = (GSH +jWCSH)-llSH(w) * Figure 1 shows a pictorial of the network decomposition. Figure 1. Distribution network decomposed into SE and SH networksThe SE network is the series portion of the network and the SH is the shunt ...

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Section: Connection With Laplace Transform Methodsmentioning

confidence: 99%

“…Modal phenomena such as variation of R or L with frequency (due to soil resistivity variation [l], for example) are not modelled. Methodologies to handle frequency dependence by transform methods exist [14,16], but are not considered here.…”

mentioning

confidence: 99%

A new method for the calculation of subtransmission and distribution system transients based on the FFT

Heydt

1989

IEEE Trans. Power Delivery

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“…Langmuir adsorption isotherm is an ideal isotherm for physical and chemical adsorption [13,14] as well, This isotherm can be represented as,…”

Section: Adsorption Isotherm and Thermodynamic Measurementsmentioning

confidence: 99%

The study of henna leaves extract as green corrosion inhibitor for mild steel in acetic acid

Chaudhari¹,

Vashi²

2016

J. Fundam and Appl Sci.

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The inhibitive action of henna (Lawsonia Inermis) leaves on mild steel in acetic acid solution have been investigated by weight-loss, A C impedance and potentiodynamic polarization measurements. The study indicates that as acid concentration increases corrosion rate increases. The corrosion inhibition efficiency increases with increase in concentration of extract. The result obtained revealed that henna leaves extract act as an efficient inhibitor. The adsorption of the henna leaves extract obeyed Langmuir adsorption isotherm. The calculated thermodynamic parameters indicated that the adsorption was a spontaneous, exothermic process accompanied by an increase in entropy. Cathodic and anodic polarization curves show that henna leaves extract is a mixed-type inhibitor.

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“…Some are based on time domain techniques [1], [2], [13]- [15] while others on frequency domain techniques [16], [17]. Models for transmission towers using NUL's have been also published [18], [19].…”

Section: Introductionmentioning

confidence: 98%

“…Due to the non-smooth nature of the transient parameters, the convolutions in (15) are solved using complex conjugate pairs of poles and residues [12]. Hence, the rational approximation of the Laplace domain spectrum of Vtis given by the following expression: (20) Applying the central differences rule to (20) and in accordance to (16), the total convolution can be written as follows: By numerical integration of (30) along the characteristic lines, as shown in Fig. 1, known solutions of voltages and currents at any time step t can be extended to the time t+At as follows: The method of characteristics consists of transforming the Partial Differential Equations of the transmission line in ordinary differential equations [22].…”

Section: Introductionmentioning

confidence: 99%

A Uniform Line Model for Non-Uniform Single-Phase Lines with Frequency Dependent Electrical Parameters

Moreno

Gómez

Davila

et al. 2006

2006 IEEE/PES Transmission &Amp; Distribution Conference and Exposition: Latin America

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In this work a new model for analyzing single-phase non-uniform transmission lines with frequency dependent electrical parameters is presented. The model is based on synthesizing an equivalent uniform transmission line. The frequency and the space dependence of the electrical parameters of the non-uniform line are introduced into the equivalent uniform line by means of a transient resistance and a shunt transient conductance. Index Terms-Frequency domain synthesis, method of Characteristics, non-uniform transmission line, transient parameters.

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s-domain analysis of electromagnetic transients on nonuniform lines

Cited by 33 publications

References 13 publications

A new method for the calculation of subtransmission and distribution system transients based on the FFT

A new method for the calculation of subtransmission and distribution system transients based on the FFT

The study of henna leaves extract as green corrosion inhibitor for mild steel in acetic acid

A Uniform Line Model for Non-Uniform Single-Phase Lines with Frequency Dependent Electrical Parameters

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