Farhad Rachidi-Haeri | EPFL Graph Search

Farhad Rachidi (IEEE Fellow, EMP Fellow, Electromagnetics Academy Fellow) was born in Geneva in 1962. He received the M.S. degree in electrical engineering and the Ph.D. degree from the Swiss Federal Institute of Technology, Lausanne, in 1986 and 1991 respectively.

He worked at the Power Systems Laboratory of the same institute until 1996 and had several short stays at the University of Florida and the NASA Kennedy Space Center. In 1997, he joined the Lightning Research Laboratory of the University of Toronto in Canada and from April 1998 until September 1999, he was with Montena EMC in Switzerland. He is currently a titular professor and the head of the EMC Laboratory at the Swiss Federal Institute of Technology, Lausanne, Switzerland.

His research interests concern electromagnetic compatibility, lightning electromagnetics and electromagnetic field interactions with transmission lines.

Dr. Rachidi is currently a member of the Advisory Board of the IEEE TRANSACTIONS ON ELECTROMAGNETIC COMPATIBILITY and the President of the Swiss National Committee of the International Union of Radio Science.

He has received numerous awards including the 2005 IEEE EMC Technical Achievement Award, the 2005 CIGRE Technical Committee Award, the 2006 Blondel Medal from the French Association of Electrical Engineering, Electronics, Information Technology and Communication (SEE), the 2016 Berger Award from the International Conference on Lightning Protection, the 2016 Best Paper Award of the IEEE Transactions on EMC, and the 2017 Motohisa Kanda Award for the most cited paper of the IEEE Transactions on EMC (2012-2016).

In 2014, he was conferred the title of Honorary Professor of the Xi’an Jiaotong University in China.

He served as the Vice-Chair of the European COST Action on the Physics of Lightning Flash and its Effects from 2005 to 2009, the Chairman of the 2008 European Electromagnetics International Symposium, the President of the International Conference on Lightning Protection from 2008 to 2014, the Editor-in-Chief of the Open Atmospheric Science Journal (2010-2012) and the Editor-in-Chief of the IEEE TRANSACTIONS ON ELECTROMAGNETIC COMPATIBILITY from 2013 to 2015. He is a Fellow of the IEEE and of the SUMMA Foundation, and a member of the Swiss Academy of Sciences.

He is the author or coauthor of over 200 scientific papers published in peer-reviewed journals and over 400 papers presented at international conferences.

A review of the modeling approaches of the lightning M-component with special attention to their current and electric field characteristics

Mohammad Azadifar, Qi Li, Carlo Alberto Nucci, Farhad Rachidi-Haeri, Marcos Rubinstein

In this paper, we present the characteristics of current, electric fields and modeling approaches of lightning M-component mode of charge transfer. We consider both the classical M-components (occurring after return strokes) and M-component-type ICC (Initial Continuous Current) pulses occurring during the initial (ICC) phase of upward flashes. M-component-type ICC pulses can be distinguished from mixed-mode pulses using different criteria: (i) the 10–90% current risetime at the channel-base with respect to an 8-µs risetime; (ii) the time lag between the onset of the current and electric fields with a respect to a threshold of 10 µs; (iii) an asymmetrical waveform coefficient (AsWc) with respect to a value of 0.8; (iv) the relative height of the junction or connection points on the grounded channel above the ground. The features of M-component electric field waveforms are summarized for close, intermediate, and far distance ranges. The observed millisecond-scale slow-part pulse shows a polarity reversal from an initial-negative waveform at close range, to a full positive-flattening late-time response at intermediate range and a bipolar wave-shape at the far distance range. One or some microsecond-scale fast pulses (junction pulse) are observed to precede the millisecond-scale slow part pulse at intermediate and far distance ranges. The microsecond-scale fast pulses are dominated by unipolar pulses along with several cases of bipolar pulses exhibiting initial polarities of both signs. The main advantage of the guided wave model and its variations is their simplicity and straightforward implementation. The guided wave model is also able to reproduce reasonably well the observed slow electric fields. The nonlinear models are more physics-based compared to the guided wave models. They are based on an important number of adjustable parameters, many of which cannot be directly inferred from experimental observations. The significance of M-components is reviewed according to practical aspects in transformer secondary, surge protective devices (SPD), grounding systems.

2023

A review of time reversal-based methods applied to fault location in power networks

Mario Paolone, Farhad Rachidi-Haeri, Reza Razzaghi, Zhaoyang Wang

Electromagnetic time reversal (EMTR)-based methods have been applied to the problem of fault location in power networks since 2012. Over the past decade, considerable theoretical investigations have led to a continuous improvement of the EMTR method in terms of fault location accuracy and efficiency. Meanwhile, different full-scale experiments, including pilot tests, were carried out, demonstrating the applicability and robustness of the EMTR method when applied to real power-system environments. This paper presents a review of the foregoing theoretical and experimental studies. Furthermore, suggestions for future studies are propounded, along with discussing various challenging research questions that still need to be addressed.

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

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 are performed to evaluate the accuracy of a closed-form approximation for the calculation of the ground-return admittance of underground cable systems. The validations are based on the full-wave finite-difference time-domain (FDTD) method and consider the calculation of transients on flat and trefoil underground cable arrangements for different excitation types. Short cable lengths of 50 m and 100 m and soil resistivities of up to 1000 Ωm are considered. The results demonstrate the validity of the transmission line theory for the calculation of fast transients (with risetimes as low as 0.2 µs) on underground cables provided the ground-return parameters are rigorously determined, with the advantage of presenting much greater efficiency and easiness to implement in electromagnetic transient simulators compared to the full-wave FDTD method. Lastly, it is shown that the ground-return admittance approximation, despite its simplicity, leads to results comparable to those obtained through more complete formulations for the calculation of transients in underground cables, but more efficiently and without significant loss of accuracy.

2023

A review of the modeling approaches of the lightning M-component with special attention to their current and electric field characteristics

Mohammad Azadifar, Qi Li, Carlo Alberto Nucci, Farhad Rachidi-Haeri, Marcos Rubinstein

2023