Assessment of the Influence of Ground Admittance Correction and Frequency Dependence of Electrical Parameters of Ground of Simulation of Electromagnetic Transients in Overhead Lines

• Published in: Journal of control, automation & electrical systems Vol. 33; no. 3; pp. 1066 - 1080
• Main Authors: Diniz, Fernando Almeida, Alípio, Rafael Silva, Moura, Rodolfo Antonio Ribeiro de
• Format: Journal Article
• Language: English
• Published: New York Springer US 2022; Springer Nature B.V
• Subjects: Approximation; Control; Control and Systems Theory; Electrical Engineering; Electrical impedance; Engineering; Frequency ranges; Ground motion; Lightning; Mechatronics; Parameters; Power lines; Robotics; Robotics and Automation; Simulation; Transmission lines; Transmission line; Electromagnetic transients; Ground return impedance; Ground admittance; Frequency dependence of soil electrical parameters
• ISSN: 2195-3880; 2195-3899
• DOI: 10.1007/s40313-021-00849-z

This paper investigates the influence of the ground admittance correction and the frequency dependence of ground conductivity and permittivity on the simulation of electromagnetic transients in overhead lines. Line parameters are calculated using an accurate formulation that considers ground displacement currents, ground admittance correction, and a rigorous voltage definition. The frequency dependence of ground parameters is calculated considering a causal model based on measurements over a wide frequency range. The calculations are performed in the frequency domain and time domain results are obtained from Laplace numerical transform. Two test cases are considered, namely a vertical 138-kV line and a horizontal 230-kV line. The results show that the frequency dependence of the electrical parameters of ground may be relevant in the simulation of lightning transients in overhead lines considering the injection of currents representative of first and subsequent lightning strokes, especially if the transmission line is located above a poor conducting ground. The effect of frequency dependence of ground parameters is more significant in the case of subsequent stroke currents since they present higher frequency content compared to first strokes. Also, it is shown that the use of Carson's approximation leads to significant deviations in lightning transient’s simulation in overhead lines, taking as reference the results obtained from the use of a more accurate formulation for line ground-return parameters calculation, mainly in the case of high-resistivity soils. On the other hand, in the case of line switching transients, the influence of frequency dependence of ground parameters and ground admittance correction is negligible, and Carson’s approximation leads to accurate results.