Evaluation of Length, Dependent Earth Return Transmission-Line Parameters for Overhead Conductors in the Quasistatic Range

• Published in: IEEE transactions on power delivery Vol. 33; no. 4; pp. 1589 - 1598
• Main Authors: Nichols, Phillip, Summers, Terrence J.
• Format: Journal Article
• Language: English
• Published: New York IEEE 01-08-2018; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Admittance; Capacitance; Conductors; Configurations; Current distribution; Earth; image approximation; Impedance; Mathematical models; matrix pencil method; mutual coupling; Numerical integration; Numerical methods; Parameters; Power transmission lines; quasistatic; Reflectance; Transmission lines
• ISSN: 0885-8977; 1937-4208
• DOI: 10.1109/TPWRD.2017.2743705

In this paper, a novel application of the matrix pencil method (MPM) is used to evaluate the length-dependent earth return parameters of overhead transmission lines in the quasistatic frequency range. The MPM is used to approximate the reflection coefficient by a series of complex exponentials, which allows the length-dependent transmission-line parameters to be evaluated in closed form. This methodology improves the accuracy of the length-dependent formulation when compared with the single image approximation used in previous publications, and can be applied to both parallel and angled overhead conductor configurations. Where large differences in results exist between the two methods, numerical integration confirms the accuracy of the MPM method. The proposed method can accurately evaluate the earth return parameters for conductors of arbitrary length and separations. This enables the proposed method to be applied to transmission-line configurations of all lengths, even in instances where the application of the per-unit method is not valid. This makes the length-dependent methodology ideal for generating transmission-line models from routing coordinates.