Publications related to Time-domain reflectometer

Validation of short-pulse reflectometry turbulence measurements with a synthetic diagnostic

Stefano Coda, Stephan Brunner, Oleg Krutkin, Umesh Kumar, Mackenzie Peter-Fulford Van Rossem, Samuele Mazzi

Experimental measurements of the turbulence amplitude utilizing a short pulse reflectometry method are presented. Two discharges with shaped plasma possessing opposite signs of triangularity are considered and a higher turbulence amplitude is found in the ...

IOP Publishing Ltd2024

Electromagnetic time reversal for online partial discharge location in power cables: Influence of interfering reflections from grid components

Farhad Rachidi-Haeri, Marcos Rubinstein

In online single-sided partial discharge (PD) location, the measured PD reflection patterns are affected by the characteristics of all the components of the associated power network. This paper analyses the performance of a PD location method based on elec ...

2024

An Effective EMTR-Based High-Impedance Fault Location Method for Transmission Lines

Farhad Rachidi-Haeri, Rong Zeng

This article summarizes the electromagnetic time-reversal (EMTR) technique for fault location, and further numerically validates its effectiveness when the fault impedance is negligible. In addition, a specific EMTR model considering the fault impedance is ...

2021

High resolution density pedestal measurements during edge localized modes by short-pulse reflectometry in the TCV tokamak

Stefano Coda, Benoît Labit, Laurie Porte, Pedro Andres Molina Cabrera

This publication presents high spatio-temporal resolution (mm/μs) density profile measurements of the pedestal top during type I, III, and small edge localized mode (ELM) H- mode plasmas in the Tokamak à Configuration Variable (TCV). These measurements wer ...

2021

The Upper Bound of the Speed of Propagation of Waves along a Transmission Line

Farhad Rachidi-Haeri, Marcos Rubinstein

According to theory, once certain conditions are fulfilled, current and voltage pulses propagate along ideal transmission lines with the speed of light. One can reach such a conclusion only when the conductors are assumed to be perfectly conducting, which ...

2020

Tokamak plasma edge studies by microwave short-pulse reflectometry and backscattering

Pedro Andres Molina Cabrera

Moving towards an increased understanding of the dynamic processes in the edge of tokamak plasmas requires continuous innovation in diagnostic capabilities, pushing the envelope in both spatial and temporal dimenstions. Plasma density and rotation, and the ...

EPFL2019

Tower and Path-Dependent Voltage Effects on the Measurement of Grounding Impedance for Lightning Studies

Marcos Rubinstein, Antonio Sunjerga, Hamidreza Karami, Keyhan Sheshyekani

We present an analysis aimed at evaluating the effect of the presence of the tower on the measurement of the grounding impedance. The Numerical Electromagnetics Code NEC-4 is used for the full-wave modeling of the structure including the tower and its foot ...

2019

Pulse Reflectometer and Doppler back-scattering diagnostics in the TCV Tokamak

Stefano Coda, Laurie Porte, Pedro Andres Molina Cabrera

Latest DBS and Pulse reflectometer developments in the TCV tokamak are presented ...

2018

Modeling of EMP Coupling to Lossless MTLs in Time Domain Based on Analytical Gauss-Seidel Iteration Technique

Farhad Rachidi-Haeri, Jun Guo

This paper provides an efficient way to simulate the transient electromagnetic field coupling to overhead multi conductor transmission lines in time domain based on an analytical iterative technique. The method is entirely in time domain and therefore can ...

2018

Study of the Propagation of Common Mode IEMI Signals Through Concrete Walls

Farhad Rachidi-Haeri, Marcos Rubinstein, Nicolas Mora Parra, Gaspard Lugrin

In this paper, a model to analyze the propagation of intentional electromagnetic interferences disturbances along penetrating conductors into concrete walls is proposed. The model is based on the transmission line theory and considers the attenuation of th ...

Institute of Electrical and Electronics Engineers2018

Stable Simulation of Nonlinearly Loaded Lossy Transmission Lines with Time Marching Approach

Farhad Rachidi-Haeri, Akiyoshi Tatematsu

A stable method for the analysis of lossy transmission lines with nonlinear loads is presented. The simulation employs the time marching (TM) method for solving the convolution equations in the time domain. To cope with the late-time instability of the TM ...

Ieee2016

Locating Faults on Untransposed, Meshed Transmission Networks Using a Limited Number of Synchrophasor Measurements

Mario Paolone, Sadegh Azizi

The method of symmetrical components is not effective for fault location in the case of untransposed lines, due to potential couplings between the sequence circuits. This paper proposes a non-iterative algorithm in the phase-coordinates for wide-area fault ...

IEEE Institute of Electrical and Electronics Engineers2016

Seismic response of rock joints under obliquely incident wave

Yang Zou

Seismic response of joints which are found to be ubiquitous in rock masses is of great interest to rock engineers, geophysicists and seismologists. In the past years, wave propagation across rock joints has been the subject of extensive theoretical and exp ...

EPFL2016

Small antennas as wireless system components

Nuno Miguel Faria Pires

Small antennas, or more specifically, electrically small antennas, are passive radiating elements whose size is much smaller than the operating wavelength. The current wireless application systems usually have size constraints that, for the most common ope ...

EPFL2014

An Efficient Method Based on the Electromagnetic Time Reversal to Locate Faults in Power Networks

Farhad Rachidi-Haeri, Mario Paolone, Carlos Alberto Romero Romero, Reza Razzaghi, Gaspard Lugrin

This paper presents a new method based on the electromagnetic time-reversal (EMTR) theory for locating faults in power networks. The applicability of the EMTR technique to locate faults is first discussed. Using the classical transmission-line equations in ...

Institute of Electrical and Electronics Engineers2013

Sparse Reverberant Audio Source Separation via Reweighted Analysis

Jean-Philippe Thiran, Pierre Vandergheynst, Yves Wiaux, Rafael Eduardo Carrillo Rangel

We propose a novel algorithm for source signals estimation from an underdetermined convolutive mixture assuming known mixing filters. Most of the state-of-the-art methods are dealing with anechoic or short reverberant mixture, assuming a synthesis sparse p ...

Institute of Electrical and Electronics Engineers2013

Application of a partial element equivalent circuit method to lightning surge analyses

Farhad Rachidi-Haeri

This paper presents the application of the partial element equivalent circuit (PEEC) method in the time and frequency domains for calculating tower surge responses and insulator voltages of an actual transmission tower, and transient performance of groundi ...

Elsevier2013

Electromagnetic Simulation of CERN Accelerator Components and Experimental Applications

Carlo Zannini

Wakes and impedances of single accelerator elements can be obtained by means of theoretical calculation, electromagnetic (EM) simulations or bench measurements. Since theoretical calculations apply only to simple structures and bench measurements have some ...

EPFL2013

Observations on turbulence and beam-ion driven modes in TEXTOR

Stefano Coda, Mattia Albergante, Cornelis Adrianus de Meijere

At a sufficiently weak toroidal magnetic field, neutral beam injection heated, limited plasmas in the TEXTOR tokamak exhibit bursts of beam-ion driven 'fishbone' and Alfven modes, which are characterized for the first time using the multi-antenna reflectom ...

Iop Publishing Ltd2012

InAlN/GaN MOSHEMT With Self-Aligned Thermally Generated Oxide Recess

Nicolas Grandjean, Jean-François Carlin, Eric Feltin

We report on lattice-matched InAlN/GaN MOSHEMTs with an oxide-filled recess, self-aligned to the gate prepared by thermal oxidation at 800 degrees C in oxygen atmosphere. The device delivered a maximum current density of 2.4 A/mm. Pulse measurements showed ...

Institute of Electrical and Electronics Engineers2009