Publications by 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

Importance of Ground Return Parameters in Transient Analysis of Overhead Wires

Farhad Rachidi-Haeri, Rafael Silva Alipio

This study assesses the accuracy of the formulations of Carson and Sunde in modeling ground effects on overhead wires, particularly for high-frequency transients and high-resistivity soils. The results reveal that these traditional formulations tend to und ...

International Union of Radio Science (URSI)2023

Assessment of the Transient Response of Wind Turbine Grounding Systems to Upward Negative Lightning

Farhad Rachidi-Haeri, Marcos Rubinstein, Mohammad Azadifar, Rafael Silva Alipio

2023

An FDTD-Based Formulation for Solving the Transmission Line Equations for a Bare Wire Buried in a Dispersive Soil

Farhad Rachidi-Haeri, Rafael Silva Alipio

2023

Closed-Form Expressions for the Calculation of the Ground-Return Impedance and Admittance of Underground Cables

Rafael Silva Alipio

This paper proposes closed-form expressions for the calculation of the ground-return impedance and admittance of underground cables. The proposed expressions are shown to reproduce the integral equations of Xue with great accuracy for a wide range of groun ...

IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC2023

Assessment of the Feasibility of Applying the Electromagnetic Time Reversal Theory to Locate Defects in Grounding Electrodes

Farhad Rachidi-Haeri, Marcos Rubinstein, Hamidreza Karami, Rafael Silva Alipio

In recent years, the electromagnetic time reversal (EMTR) theory has been successfully applied for locating various sources of disturbances, such as short-circuit faults, in power systems. In this paper, a theoretical analysis of the feasibility of applyin ...

2023

Tower-foot grounding model for EMT programs based on transmission line theory and Marti's model

Rafael Silva Alipio

This paper proposes a tower-foot grounding system model compatible with EMT programs which might be useful for the simulation of lightning transients in overhead lines. The proposed model is based on the solution of the telegrapher's equations and the appl ...

Elsevier2023

On the Use the Electromagnetic Time Reversal Theory to Locate Breakpoints in Grounding Electrodes

Farhad Rachidi-Haeri, Marcos Rubinstein, Hamidreza Karami, Rafael Silva Alipio

2023

A Comprehensive Analysis on the Influence of the Adopted Cumulative Peak Current Distribution in the Assessment of Overhead Lines Lightning Performance

Rafael Silva Alipio

Backflashover rate (BFR) is strongly dependent on the cumulative peak current distribution (CCD) adopted in the calculations. An original aspect of the present work is that such dependence is simultaneously assessed in estimating the probability of the cri ...

MDPI2023

An Overview of the Propagation and Surge Characteristics of Interconnected Wind Turbine Grounding Systems

Farhad Rachidi-Haeri, Rafael Silva Alipio

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

2023