Method for Determining the Resonant Frequencies of Extra High Voltage Power Transmission Line

Abstract

The paper proposes a mathematical model for determining the resonant frequency of a 750 kV line relative to an unloaded transformer and studies the possibility of overvoltages in 750 kV lines at the 2nd harmonic. A resonant circuit has been compiled to determine the natural frequencies of an ultrahigh voltage power line to analyze the conditions for overvoltages at higher harmonic components. Analytical expressions are obtained to determine the degree of influence of the line parameters' value on the line's resonant frequency. The paper presents the relationship between the operating mode of an ultra-high voltage power line and an autotransformer (transformer) on the conditions for the existence of overvoltages. Analytical expressions for evaluating the influence of the degree of charging power compensation on the values of the mode parameters of the ultra-high voltage power transmission line are given.