Publications de Rafael Silva Alipio

Reliability of High-Frequency Earth Meters in Measuring Tower-Footing Resistance: Simulations and Experimental Validation

This paper presents a comprehensive assessment of the accuracy of high-frequency (HF) earth meters in measuring the tower-footing ground resistance of transmission line structures, combining simulation and experimental results. The findings demonstrate tha ...

MDPI AG2025

Probabilistic Load-Shedding Strategy for Frequency Regulation in Microgrids Under Uncertainties

Rafael Silva Alipio

This paper proposes a novel integer-mixed probabilistic optimal power flow (IM-POPF) strategy for frequency regulation in islanded microgrids under uncertain operating conditions. Existing load-shedding approaches face critical limitations: continuous fram ...

MDPI AG2025

An EMTP-Compatible Frequency-Dependent Model for Vertical Grounding Rods for Transient Studies

Farhad Rachidi-Haeri, Rafael Silva Alipio

This paper proposes an extended RLC circuit model for grounding rods that incorporates the frequency-dependent nature of both the grounding input impedance and the soil electrical parameters. The accuracy of the model, in terms of its predictions for Groun ...

2024

Concrete Encased Grounding: Lightning Response Analysis Considering the Frequency Dependence of Soil

Rafael Silva Alipio

Grounding system design ensures safety compliance for transmission lines under lightning conditions. In this article, the transient response of short concrete encased grounding electrodes is investigated, that is, a 2.5 m vertical rod and a 10 m horizontal ...

2024

Field-Induced Voltages and Currents on Buried Cables: Accurate As-sessment of Lossy Ground Effects

Farhad Rachidi-Haeri, Rafael Silva Alipio

This paper revisits the topic of induced voltages and currents in underground cables, building on recent advancements in both cable coupling and soil modeling. The induced current in an underground cable is computed by solving the field-to-buried cable cou ...

VDE publishing house2024

High-frequency transients in buried insulated wires: Transmission line simulations and experimental validation

Farhad Rachidi-Haeri, Rafael Silva Alipio

This paper presents experimental results on the transient response of a buried insulated wire subjected to fast transient signals. It reports measurements of voltage and current at the sending end, as well as the voltage at the receiving end of the insulat ...

Elsevier2024

Assessment of the accuracy of the modal-domain line models with real and frequency-independent transformation matrix for electromagnetic transient simulation in lines with underbuilt cables

Rafael Silva Alipio

This paper investigates the potential inaccuracies associated with using a modal-domain model featuring a real and frequency-independent transformation matrix in simulating electromagnetic transients on power overhead lines equipped with underbuilt wires. ...

Elsevier2024

Influence of a lossy ground on the lightning performance of overhead transmission lines

Farhad Rachidi-Haeri, Rafael Silva Alipio

This paper investigates the impact of incorporating both displacement currents and frequency-dependent soil parameters in the calculation of the ground-return impedance for the determination of the backflashover rate of 138 kV and 230 kV overhead transmiss ...

Elsevier2023

Comparison of Different Formulations to Compute the Ground Return Parameters in the Analysis of High-Frequency Pulse Propagation Along a Wire Above a Lossy Ground

Farhad Rachidi-Haeri, Rafael Silva Alipio

The propagation characteristics along a single-conductor line above a lossy ground are assessed considering different formulations to compute the ground correction terms in the per-unit-length line parameters. It is shown that the often-used Sunde’s formul ...

2023

Assessment of the transmission line theory in the modeling of multiconductor underground cable systems for transient analysis using a full-wave FDTD method

Farhad Rachidi-Haeri, Rafael Silva Alipio

In this paper, a rigorous and independent validation of two different approaches for calculating the ground-return impedance and admittance of multiconductor underground cable systems using the transmission line theory is carried out. Furthermore, analyses ...

Elsevier2023