Farhad Rachidi-Haeri

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Since 1991, a broadband, high-resolution current measurement system has captured the lightning current derivative at the Toronto CN Tower. In this paper, extensive statistics (1992-2001) of CN Tower lightning current waveform parameters (maximum steepness and peak) are compared with waveform parameters of currents recorded at other elevated objects, including rockets trailing conducting wires. The influence of the height of the struck object on waveform parameters is analyzed. The paper focuses on the compa

Several recent publications show that the electromagnetic radiation generated by transmitting antennas satisfy the following universal conditions: The time domain radiation fields satisfy the condition A ≥ h/4π ⇒ q ≥ e where A is the action of the radiatio ...

One of the main issues that has to be faced when evaluating lightning-induced overvoltages on a realistic network configuration is to implement the algorithm that solves the field-to-line coupling problem into an electromagnetic simulator that is able to r ...

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 ...

The lightning return stroke model by Master, Uman, Lin, Standler (1981) (MULS), a modification of the Lin, Uman, Standler (1980) (LUS) model, can be viewed mathematically as having a specified channel-base current, although in the original formulation it was the channel current sources that were specified. The specification of the MULS channel-base current is independent of the time dependence of the corona current sources which characterize the MULS model. Further, when starting from the same channel-base

Gas-insulated switchgear (GIS) are some of the most reliable and most expensive equipment that are nowadays used in power systems. Condition monitoring of the power system equipment can help operators detect defects like partial discharges (PDs) early, pre ...

We propose in this paper the use of a monopolar version of the Yagi-Uda antenna connected to a switched oscillator (SWO). At the resonance frequency, this antenna offers a higher impedance than, for example, a Half Impulse Radiating Antenna (HIRA), a helic ...

This paper is aimed at analyzing the influence of the frequency-dependent behavior of the ground electrical parameters ( conductivity and ground permittivity) on the electromagnetic field radiated by a cloud-to-ground lightning return stroke. Both radiatio ...

The coupling of electromagnetic fields inside shielded cables is an important issue in EMC applications, in which the transfer impedance represents one of the main parameters. The paper discusses the last analytical expressions which have been developed for the transfer impedance of braided cables. A general approach for the determination of the internal response of a shielded cable to an external electromagnetic excitation is presented in the frequency domain using the BLT equations. Then, an equivalent ti

The paper presents experimental results obtained as part of the GEMCAR European project using the VERIFY EMP simulator belonging to the Swiss Defense Procurement Agency (Spiez). VERIFY generates a vertically polarized electric field with a rise time of 0.9 ns and an FWHM of 24 ns. The working volume is 4×4×2.5 m3 and the maximum E-field amplitude is 100 kV/m. Two experimental models for the vehicle and the cable harness were used for the tests. Measurements of electric and magnetic fi

Simultaneous measurements of current and multiple‐station electric fields associated with a 5.4‐kA‐peak M‐component in rocket‐triggered lightning are presented in this study. A close‐range electric field measurement site was located northeast of the trigge ...

In this paper, an improved model of the vertical risers of a transmission line is proposed and validated. The proposed improved model, which can be readily implemented in the frame of a classical transmission line formulation, provides accurate results at ...

The paper aims at defining a methodology to evaluate the lightning performance of a system of overhead distribution lines. As is well known, the evaluation of the lightning performance relies generally on a Monte Carlo approach that generates many differen ...

In this paper, we investigate the effect of periodically-grounded shielding wires and surge arresters on the attenuation of lightning-induced voltages. We discuss the adequacy of the commonly made simplification of assuming the shielding wire at ground potential, instead of being treated as one of the conductors of the multiconductor system. We also compare then the mitigation effect of shielding wires with that achievable by the insertion of surge arresters along the line. The computation results are first

The knowledge of lightning current parameters comes essentially from direct measurements obtained using instrumented towers or triggered lightning, and from measurements of lightning electromagnetic fields assuming empirical or theoretical relations between fields and currents (indirect estimation). In this paper, the effects of an elevated strike object on both the direct and indirect estimation of the current parameters is examined. It is shown that relatively short strike objects, such as triggered light

We present in this paper an extension of the guided-wave M-component model of Rakov et al. considering the presence of a vertically elevated strike object. The tall object is represented as a lossless, uniform transmission line. Expressions for the current ...

We present an alternative method based on the time-reversal process to locate faults in transmission line networks. The proposed procedure considers different media for the forward and the backward propagation phases. Specifically, the transverse branch re ...

In this paper, we compare five engineering return stroke models, extended to include the presence of an elevated strike object, namely the Bruce-Golde (BG) model, the transmission line (TL) model, the traveling current source (TCS) model, and the two modif ...

Electromagnetic Time Reversal (EMTR) has been used to locate different types of electromagnetic sources. We propose a novel technique based on the combination of EMTR and Machine Learning (ML) for source localization. We show for the first time that ML tec ...

A complete framework dealing with power line communication in medium voltage network is proposed. Based on path loss measurements, a complete characterisation of inductive couplers is performed. After a brief recall of inductive coupling techniques, we address the issue of power switching influence on inductive coupler performances. Finally, we show the key role of the medium voltage to low voltage transformer for a phase to ground propagation mode

Farhad Rachidi-Haeri

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Comparison of current characteristics of lightning strokes measured at the CN tower and at other elevated objects

Hints of the Photonic Nature of the Electromagnetic Fields in Classical Electrodynamics

On the Stability of FDTD-Based Numerical Codes to Evaluate Lightning-Induced Overvoltages in Overhead Transmission Lines

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

On the Master, Uman, Lin, Standler and the Modified Transmission Line lightning return stroke current models

Partial discharge localization using time reversal: Application to gas insulated switchgear

Design of an Efficient High Power Electromagnetic Radiator using a Yagi-Uda Antenna Connected to a Switched Ocillator

The influence of frequency dependent soil electrical parameters on the evaluation of lightning electromagnetic fields in air and underground

Electromagnetic field coupling to shielded cables: methodology and experimental validation

Electromagnetic field interaction with vehicle cable harness: an experimental analysis

Measurement and Modeling of Both Distant and Close Electric Fields of an M‐Component in Rocket‐Triggered Lightning

Electromagnetic Field Coupling to Transmission Lines: A Model for the Risers

Evaluation of Power System Lightning Performance—Part II: Application to an Overhead Distribution Network

Mitigation of Lightning-Induced Overvoltages in Medium Voltage Distribution Lines by Means of Periodical Grounding of Shielding Wires and of Surge Arresters: Modeling and Experimental Validation

On the influence of elevated strike objects on directly measured and indirectly estimated lightning currents

An Extension of the Guided Wave M‐Component Model Taking Into Account the Presence of a Tall Strike Object

An Alternative Method for Locating Faults in Transmission Line Networks Based on Time Reversal

Return stroke current profiles and electromagnetic fields associated with lightning strikes to tall towers: Comparison of engineering models

Single-Sensor Source Localization Using Electromagnetic Time Reversal and Deep Transfer Learning: Application to Lightning

Influence of power switching on power line communications in medium voltage networks