| Full text | |
| Author(s): |
de Azevedo, W. L. M.
;
Pascoalato, T. F. G.
;
de Araujo, A. R. J.
;
Kurokawa, S.
;
Pissolato Filho, J.
Total Authors: 5
|
| Document type: | Journal article |
| Source: | Electric Power Systems Research; v. 251, p. 8-pg., 2025-09-12. |
| Abstract | |
This paper addresses the influence of concrete on the overvoltages developed in a 138-kV transmission line (TL) subjected to lightning strikes with variable amplitude. This study considers a tower-footing grounding system consisting of four counterpoise conductors, utilizing both bare and concrete-encased electrodes. The harmonic grounding impedance is initially calculated over a frequency range from 100 Hz to 10 MHz. Subsequently, the ground potential rise (GPR) developed by the tower-footing grounding system under lightning currents with adjustable peak values is analyzed. Furthermore, the impulse impedance is computed to model the tower-footing grounding system within the simulated power network. The TL is modeled using the Universal Line Model (ULM), which incorporates frequency-dependent (FD) soil parameters and ground-return parameters calculated via Nakagawa's equations. Simulations are performed in ATP-EMTP, where the ULM is implemented in MATLAB and incorporated into the model via a PCH file. Finally, the overvoltage waveforms generated for the 138-kV power system subjected to a lightning strike are analyzed for three different values of low-frequency soil resistivity modeled using Al & iacute;pio-Visacro's approach: 700, 1500, and 4000 Omega m. The simulation results reveal a substantial reduction in harmonic impedance for the concrete-encased grounding system compared to the bare-electrode configuration. This reduction leads to lower impulse impedance and results in GPR waveforms with significantly reduced peak values when concrete is incorporated into the grounding system. However, in high-resistivity soils, the reduction achieved by the concrete-encased system is limited to approximately 33%. In addition, the overvoltages generated by lightning strikes are lower when the concrete-encased grounding system is used. In contrast, the bare grounding system leads to backflashover events, which do not occur when the concrete-encased grounding system is used. (AU) | |
| FAPESP's process: | 21/11258-5 - Engineering Research Center for the Aerial Mobility of the Future (ERC-AMF) |
| Grantee: | Domingos Alves Rade |
| Support Opportunities: | Research Grants - Applied Research Centers Program |
| FAPESP's process: | 22/09182-3 - Modeling of multiphase transmission lines considering frequency-dependent soil parameters: Transient analysis via ATP software |
| Grantee: | Tainá Fernanda Garbelim Pascoalato |
| Support Opportunities: | Scholarships abroad - Research Internship - Doctorate |
| FAPESP's process: | 20/10141-4 - Influence of the soil electromagnetic characteristics in the transient responses in electric transmission lines |
| Grantee: | Tainá Fernanda Garbelim Pascoalato |
| Support Opportunities: | Scholarships in Brazil - Doctorate |