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1

The Transient Performance of Partially-Undergrounded Overhead Lines in the Presence of Corona

Saied Mohamed M.

Electrical Power Quality and Utilisation. Journal

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2019

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Vol. 21, iss. 1

1--8

EN

The paper presents a method for investigating the electromagnetic transients of partially under-grounded high voltage overhead transmission lines in the presence of corona. It is based on a time domain model in which the corona is simulated by distributed voltage-dependent shunt current sources. The line segments and the inserted cable section are represented by a single equivalent transmission element having location-dependent circuit parameters per unit length. The numerical solution of the resulting set of differential equations yields the distributions of the voltage, the longitudinal current and the shunt corona current (per unit length) as functions of location and time. The presented two-, three-dimensional and contour plots proved to be helpful in discussing these distributions and in identifying any eventual current and/or voltage concentrations. The developed computer code in Mathematica can handle any time waveform of the source initiating the transients, any line termination as well as any lengths of the overhead line and cable section.

2

Algorytm do polioptymalizacji z odpowiednio przystosowanąmetodą ewolucji ekstrapolacyjnej

Grzyb. A.

Pomiary Automatyka Kontrola

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2007

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R. 53, nr 8

13-16

PL

W pracy opisano zmiany dokonane w związku z przystosowaniem optymalizacyjnej metody ewolucji ekstrapolacyjnej - dokładniej przedstawionej we wcześniej opublikowanych pracach autora - do wykonywania polioptymalizacji. Jej celem jest dążenie do wyznaczenia możliwie licznego zbioru paretooptymalnych rozwiązań problemów z wieloma funkcjami kryterialnymi i ograniczeniami. Przykłady zastosowań do zadań testowych, z których wybrane dwa zamieszczono w pracy świadczą o tym, że algorytm pozwala na bardzo efektywne rozwiązywanie problemów testowych i praktycznych oraz uzyskiwać wyniki lepsze od otrzymywanych znanymi już metodami.

EN

The article describes changes introduced for adjustment of optimisation method of extrapolation evolution - presented in details by the author in previously published papers - to realize polyoptimization. Its aim is to determine possibly numerous set of Pareto optimal solutions with multi-criteria functions and constrains. Implementation examples to test tasks, two of them included in the paper, prove that the algorithm enables very effective solving of test and practical problems and achieving better results than obtained by already known methods.

3

Laminar flow in trapezoidal grooves at finite Bond numbers with shear stress at the liquid-vapor interface by the method of fundamental solutions

Jopek H., Kołodziej J. A., Stręk T.

Computer Assisted Mechanics and Engineering Sciences

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2006

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Vol. 13, No. 3

395-405

EN

The problem of determination of Poiseuille number for a steady gravitational flow of liquid in an inclined open trapezoidal groove is addressed. The solution comprises of two parts. First, for a given groove's dimension, liquid-solid contact angle, and the Bond number, the shape of the free surface is determined starting from the Young--Laplace equation. The shooting method is used for solution of a two-point boundary value problem. Then, having determined the shape of the free surface and slope the groove, the fully developed laminar flow is determined. The boundary value problem is solved using the method of fundamental solutions. Given the distribution of liquid velocity, the Poiseuille number, as a function of the other parameters of the model is analysed.