Quantitative Evaluation of Frequency Impact on Resistances and Inductances of Power System’s Overhead Lines in Transient Operation Conditions

Abstract

Transient processes in electrical power systems are processes that arise when a system is disturbed. These transients are classified according to their frequencies into three groups: electromagnetic transients with a frequency range from 1 to 2 kHz to a few MHz, electromechanical transients with a frequency range of 1 MHz to 1 Hz, electromagnetic transients mechanical (can be called mixed crossings) and their frequency range between 1 and 1000-2000 Hz. It is well known that overhead resistances and inductances relate to frequency more than any other element of the system when the earth is taken into account while amplitude can be considered non-frequency and negligent G.

This paper aims at quantitative (numerical) evaluation of the effect of frequency on the resistances and inductances of overhead lines and their effect on the mathematical models of lines represented by lamped parameters, designed to calculate the performance of the power system in the case of hybrid transits. The paper includes the formulation of the mathematical model and the algorithm, the design of a software program in the Matlab environment, the computing practical examples, and analysis of computation results. The paper concludes with conclusions which are useful for the analysis and design of electrical power systems in general and in transient cases in particular.