Accuracy of approximate formulas for internal impedance of tubular cylindrical conductors for large parameters
Abstract
Exact formulas for internal impedance per unit length of tubular cylindrical conductors energized by time-harmonic current involve Bessel functions. These functions are defined by infinite series, which yield unstable and often erroneous results for complex arguments of large magnitudes. Although it is well known how to evaluate Bessel functions numerically and many routines are now available to perform the actual computation, the available software routines often fail when computing equations that consist of a product and a quotient of Bessel functions under large complex or real arguments. For such cases, different approximate formulas can be used. In this paper, three types of approximate formulas for internal impedance of tubular cylindrical conductors are compared with respect to numerical stability and accuracy.
Dino Lovrić
Associate Professor | Department of Theoretical Electrical Engineering and Modelling
Associate professor at the Faculty of Electrical Engineering, Mechanical Engineering and Naval Architecture in Split, with reserch focused on the development of numerical models of grounding systems in various types of soil, particularly in scenarios involving the dissipation of alternating current and transient currents caused by lightning strikes or switching overvoltages, also involved in developing models of dynamic and transient processes in power systems using modern numerical methods.
Slavko Vujević
Professor Emeritus
An expert in electrical engineering, particularly known for his contributions to numerical modeling of electromagnetic phenomena, lightning protection, and grounding. Throughout his career, he was a key member of the Faculty of Electrical Engineering, Mechanical Engineering, and Naval Architecture in Split, where he taught, mentored students, and actively participated in scientific research and international professional organizations.