Farhad Rachidi-Haeri

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Partial discharge (PD) occurrence in power transformers can lead to irreparable damage to the power network. In this paper, the inverse filter (IF) method to localize PDs in power transformers is proposed. To the best of the authors’ knowledge, this is the ...

We report on the mountain top observation of three terrestrial gamma-ray flashes (TGFs) that occurred during the summer storm season of 2021. To our knowledge, these are the first TGFs observed in a mountaintop environment and the first published European ...

In this paper, we present a theoretical analysis of the propagation effects of lightning electromagnetic fields over a mountainous terrain. The analysis is supported by experimental observations consisting of simultaneous records of lightning currents and ...

In this study, we present an experimental validation of the transmission line representation of an elevated object struck by lightning. The experimental results are obtained using a reduced-scale model and injected signals with narrow pulse widths (down to 500 ps). The validation is performed using a reduced scale structure representing the Toronto CN Tower in Canada. Two models consisting, respectively, of 1-section and 3-section uniform transmission lines were considered for the comparison. It is shown th

Upward lightning is the dominant type of lightning discharge to tall structures. It has been observed that a significant number of these upward flashes are initiated by nearby lightning activity. The aim of this study is to estimate the incidence of upward ...

This chapter presents the coupling of lightning electromagnetic fields to overhead and underground lines based on the transmission line approximation. The chapter starts with an introductory section in which the advantages and the drawbacks of three approa ...

Two corona models, applicable to the calculation of lightning-induced overvoltages in multiconductor overhead lines, are considered in this paper. The first model represents corona by an increase in each conductor self capacitance after the voltage has reached a threshold value, and in the second model, the influence of corona on the mutual coupling between conductors is also taken into account. Results show that corona (using any of the models) produces an increase in the overvoltage amplitudes, confirming

In this paper, for the first time, an experimental proof of concept for utilising time reversal (TR) in the acoustic regime to localise partial discharge (PD) sources was presented using a single sensor. To achieve this, an experimental setup comprising a ...

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 ...

Definitions are introduced to classify the regions of interest around PLC networks. An improvement to an existing technique for the reduction of emissions from PLC networks is proposed. Using numerical simulations, the technique is shown to reduce any one ...

In this article, we propose and implement a novel technique to locate electromagnetic interference (EMI) sources using the concept of time-reversal (TR) cavity. We show in an intuitive manner that reflections from the surfaces of a cavity can emulate an in ...

We have seen in this chapter that the FDTD method for solving Maxwell's equations is accurate and versatile in a very wide variety of applications related to lightning. One can analyze the lightning electromagnetic field propagation over distances ranging ...

Without loss of generality, the return stroke can be treated as a current pulse propagating along the leader channel while undergoing attenuation and dispersion. According to the measurements, the return stroke travels along the leader channel with a speed less than the speed of light. However, if the return stroke speed were to be lower than the speed of light, the propagating return stroke would generate an electric field traveling ahead of the return stroke front with the speed of light. Since the leader

A current propagation type return stroke model which is consistent with the estimated distribution of the charge on the leader channel is described. The model takes into account the dispersion of the return stroke current along the return stroke channel. T ...

Lightning electromagnetic pulse (LEMP) is a severe threat to sensitive electronic devices installed in buildings. To protect these devices from LEMP effects, the evaluation of the electromagnetic fields inside of the building is required. Although numerous ...

We propose a method to locate the current in a printed circuit board caused by an electrostatic discharge. This approach uses data acquired before the discharge event by using a vector network analyzer. The localization is performed by using single-shot time-domain data and the time-reversal algorithm. The time-reversal backpropagation uses experimental data, eliminating the need for numerical models of the device under test. The method allows us to distinguish two traces placed 8 mm apart.

This paper presents a derivation and a physical interpretation of the equal area rule (EAR) for wire-grid simulation of surfaces. We propose a new procedure that leads to a formulation for obtaining the radii for an arbitrarily meshed surface. A simple com ...

We present in this paper a thorough analysis of current wave propagation with arbitrary speed along an extending transmission line. We derive rigorous analytical equations in the time and frequency domains expressing the reflections of the current wave occ ...

The kernel of the Cooray-Rubinstein formula in the time domain involves a modified Bessel function of order zero. In this letter, approximations of the kernel are proposed, which do not use any special function, and, hence, are able to simplify the numeric ...

Both approaches in the frequency and in the time-domain are used in the literature for calculating the response of a line or a cable to an EMP. At the Swiss Institute for Technology from Lausanne, numerical codes using both methods have been developed and tested. Based on the experience acquired by using these codes, the advantages and disadvantages of both approaches are discussed and compared. The obtained results are also compared with similar numerical approaches developed by other authors

Farhad Rachidi-Haeri

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An Inverse-Filter-Based Method to Locate Partial Discharge Sources in Power Transformers

Mountaintop Gamma Ray Observations of Three Terrestrial Gamma‐Ray Flashes at the Säntis Tower, Switzerland With Coincident Radio Waveforms

On Lightning Electromagnetic Field Propagation Along an Irregular Terrain

On the use of transmission line theory to represent a nonuniform vertically-extended object struck by lightning

Incidence of Upward Lightning Triggered by Nearby Lightning: A Monte Carlo Simulation

Field-to-transmission line coupling models

Corona on multiconductor overhead lines illuminated by LEMP

An experimental proof of concept of time‐reversal single‐sensor acoustic source localisation: Application to partial discharges

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

Discussion on the assessment and mitigation of radiation from PLC networks

Localization of Electromagnetic Interference Sources Using a Time-Reversal Cavity

The application of the finite-difference time-domain (FDTD) technique to lightning studies

Known properties of the lightning leader channels point towards a return stroke moving with the speed of light

Current propagation type self-consistent leader-return stroke model

Analysis of Electromagnetic Fields Inside a Reinforced Concrete Building With Layered Reinforcing Bar due to Direct and Indirect Lightning Strikes Using the FDTD Method

Single-Shot Experimental Localization of Electromagnetic Interference Sources With Application to Electrostatic Discharges

A physical interpretation of the equal area rule

Relativistic Doppler effect in an extending transmission line: Application to lightning

On the Kernel of the Cooray–Rubinstein Formula in the Time Domain

Frequency and time-domain approaches in EMP coupling. A comparison between different methods of calculation