A Recursive Formula for the Evaluation of Earth Return Impedance on Buried Cables

This paper presents an alternative solution based on infinite series for the accurate and efficient evaluation of cable earth return impedances. This method uses Wedepohl and Wilcox’s transformation to decompose Pollaczek’s integral in a set of Bessel functions and a definite integral. The main feat...

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Detalhes bibliográficos
Autor: Iracheta, Reynaldo
Formato: artículo
Estado:Versión publicada
Fecha de publicación:2015
País:Colombia
Recursos:Universidad Nacional de Colombia
Repositorio:Repositorio UN
Idioma:español
OAI Identifier:oai:repositorio.unal.edu.co:unal/67641
Acesso em linha:https://repositorio.unal.edu.co/handle/unal/67641
http://bdigital.unal.edu.co/68670/
Access Level:acceso abierto
Palavra-chave:62 Ingeniería y operaciones afines / Engineering
Earth-return impedance
Pollaczek’s integral
Wedepohl’s integral
infinite series expansion
recursive formula
buried cables
Numerical Laplace Transform (NLT).
Impedancia de retorno por tierra
Integral de Pollaczek
Integral de Wedepohl
serie infinita
fórmula recursiva
cables subterráneos
Transformada Numérica de Laplace (NLT).
Descrição
Resumo:This paper presents an alternative solution based on infinite series for the accurate and efficient evaluation of cable earth return impedances. This method uses Wedepohl and Wilcox’s transformation to decompose Pollaczek’s integral in a set of Bessel functions and a definite integral. The main feature of Bessel functions is that they are easy to compute in modern mathematical software tools such as Matlab. The main contributions of this paper are the approximation of the definite integral by an infinite series, since it does not have analytical solution; and its numerical solution by means of a recursive formula. The accuracy and efficiency of this recursive formula is compared against the numerical integration method for a broad range of frequencies and cable  configurations. Finally, the proposed method is used as a subroutine for cable parameter calculation in the inverse Numerical Laplace Transform (NLT) to obtain accurate transient responses in the time domain.