Publications related to Brush discharge

Partial discharge localization in power transformer tanks using machine learning methods

Farhad Rachidi-Haeri, Marcos Rubinstein, Hamidreza Karami

This paper presents a comparison of machine learning (ML) methods used for three-dimensional localization of partial discharges (PD) in a power transformer tank. The study examines ML and deep learning (DL) methods, ranging from support vector machines (SV ...

Nature Publishing Group2024

Tailor-made Piezoelectric Elastomer Materials

Francis Owusu

Recent advancements in miniature devices with higher computational capabilities and ultralow power consumption have accelerated the development of wearable sensors, actuators, and energy harvesters everywhere. The ultimate aim of such a technological revol ...

EPFL2023

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

Farhad Rachidi-Haeri, Marcos Rubinstein, Hamidreza Karami

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 ...

Elsevier2022

Partial discharge localization in power transformers using acoustic time reversal

Farhad Rachidi-Haeri, Marcos Rubinstein, Mohammad Azadifar, Hamidreza Karami, Florent Quentin Aviolat

The localization of partial discharges (PD) is important to monitor the conditioning of high voltage insulator materials. One of the key components in power grids is the high power transformer. Localization of PDs in these pieces of equipment can increase ...

Elsevier2022

Performance and Design of a Stepped Spillway Aerator

Anton Schleiss, Michael Pfister, Stéphane Christian Olivier Terrier

Stepped spillways are frequently limited to specific discharges under around 30 m2/s due to concerns about potential cavitation damages. A small air concentration can prevent such damages and the design of bottom aerators is well established for smooth chu ...

2022

Stretchable High Response Piezoelectric Elastomers Based on Polable Polynorbornene Fillers in a Polydimethylsiloxane Matrix

Frank Nüesch, Francis Owusu

To advance the field of piezoelectrics, it is desirable to find materials that combine high piezoelectricity with high elasticity. Applications such as self-sensors, stretchable electronics, soft robots, and energy harvesting would benefit tremendously. Ho ...

WILEY-V C H VERLAG GMBH2022

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

Farhad Rachidi-Haeri, Marcos Rubinstein, Hamidreza Karami

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 ...

2022

Preliminary Design of a High Current R&W TF Coil Conductor for the EU DEMO

Pierluigi Bruzzone, Kamil Sedlák, Federica Demattè

Paschen failures in ITER, W7-X and JT60 superconducting coils at the acceptance tests have shown that it is highly desirable to lower the coil discharge voltage (U-d) of the DEMO Toroidal Field (TF) coils. Another benefit of lowering the U-d might be the r ...

IEEE Institute of Electrical and Electronics Engineers2022

A statistical approach for the automatic identification of the start of the chain of events leading to the disruptions at JET

Alessandro Pau

This paper reports an algorithm to automatically identify the chain of events leading to a disruption, evaluating the so-called reference warning time. This time separates the plasma current flat-top of each disrupted discharge into two parts: a non-disrup ...

IOP Publishing Ltd2021

An experimental validation of partial discharge localization using electromagnetic time reversal

Farhad Rachidi-Haeri, Marcos Rubinstein, Mohammad Azadifar, Hamidreza Karami

The localization of partial discharge (PD) sources is of importance for the monitoring and maintenance of power transformers. Time difference of arrival (TDoA) based methods are widely adopted in the literature for the localization of PDs. Recently, time r ...

Nature Research2021

Beware of your electrodes! How electrode materials and application processes impact the lifetime of slide-ring-material-based DEAs

Herbert Shea

For dielectric elastomer actuators (DEAs) to find more widespread adoption in commercial products, a better understanding of their durability is needed. By determining the different mechanisms contributing to ageing and breakdown in DEAs, new methods for i ...

SPIE-INT SOC OPTICAL ENGINEERING2021

Could Macroscopic Dark Matter (Macros) Give Rise to Mini-Lightning Flashes out of a Blue Sky without Clouds?

Farhad Rachidi-Haeri, Marcos Rubinstein

A recent study pointed out that macroscopic dark matter (macros) traversing through the Earth’s atmosphere can give rise to hot and ionized channels similar to those associated with lightning leaders. The authors of the study investigated the possibility t ...

2021

Partial Discharge Localization Using Electromagnetic Time Reversal: A Performance Analysis

Marcos Rubinstein, Hamidreza Karami, Mohammad Azadifar, Zhaoyang Wang, Ali Ghasemi

In this study, first, a comparison on the application of electromagnetic time reversal (EMTR) and time difference of arrival (TDoA) in partial discharge localization in power transformers is presented. A two-dimensional finite-difference time-domain simula ...

2020

New insight in Francis turbine cavitation vortex rope: role of the runner outlet flow swirl number

François Avellan, Christian Landry, Christophe Nicolet, Joao Gomes Pereira Junior, Arthur Tristan Favrel, Andres Müller

At part load operation, Francis turbines experience the development of a cavitation vortex rope in the draft tube, whose precession acts as a pressure excitation source. In case of resonance, the resulting pressure pulsations lead to unacceptable torque an ...

Taylor & Francis Ltd2018

Comparison of runaway electron generation parameters in small, medium-sized and large tokamaks-A survey of experiments in COMPASS, TCV, ASDEX-Upgrade and JET

Basil Duval, Stefano Coda, Yves Martin, Joan Decker, Gergely Papp, Giovanni Tardini

This paper presents a survey of the experiments on runaway electrons (RE) carried out recently in frames of EUROFusion Consortium in different tokamaks: COMPASS, ASDEX-Upgrade, TCV and JET. Massive gas injection (MGI) has been used in different scenarios f ...

IOP Publishing Ltd2018

Investigation of venting turbidity currents in the Rudbar-Lorestan reservoir in Iran

Anton Schleiss, Giovanni De Cesare, Azin Amini, Sabine Chamoun, Sara Venuleo

Venting of turbidity currents is known as an efficient measure to prevent reservoir sedimentation and is applied in many reservoirs globally. It has several economic and ecological advantages compared with other evacuation methods. In the literature, numer ...

2017

Reestablishment of a uniform discharge on the Olympic fountain in Lausanne

Anton Schleiss, Giovanni De Cesare, Elena Battisacco

Since its inauguration, in 1993, the horizontal weir crest of the Olympic fountain in Lausanne has suffered from differential settlings leading to a difference in level of more than 30 mm. The settling involves a visible non-uniform discharge distribution ...

Taylor & Francis Ltd2017

Experimental investigation of the mass flow gain factor in a draft tube with cavitation vortex rope

François Avellan, Arthur Tristan Favrel, Christian Landry, Andres Müller, Sébastien Alligné, Keita Yamamoto

At off-design operating operations, cavitating flow is often observed in hydraulic machines. The presence of a cavitation vortex rope may induce draft tube surge and electrical power swings at part load and full load operations. The stability analysis of t ...

2017

High sensitivity field asymmetric ion mobility spectrometer

Mario Andres Chavarria Varon

Field Asymmetric IonMobility Spectrometry (FAIMS) is a very promising technique for chemical detection. FAIMS systems are portable, highly sensitive, relatively inexpensive and can work at atmospheric conditions. These attributes make it a very desirable t ...

EPFL2016

Recent ASDEX Upgrade research in support of ITER and DEMO

Olivier Sauter, Basil Duval, Stefano Coda, Timothy Goodman, Alessandro Pau, Federico Alberto Alfredo Felici, Laurie Porte, Haomin Sun, Yann Camenen, Marco Wischmeier, Nicola Vianello, Alberto Bottino, Emiliano Fable, Andrea Scarabosio, Doohyun Kim, Dávid Wágner, Thomas Binderup Jensen, Heinz Mueller, Donghyun Kim, Xiao Wang, Bernhard Sieglin, Otto Asunta, Hartmut Zohm, Emanuele Poli, Gergely Papp, Giovanni Tardini

Recent experiments on the ASDEX Upgrade tokamak aim at improving the physics base for ITER and DEMO to aid the machine design and prepare efficient operation. Type I edge localized mode (ELM) mitigation using resonant magnetic perturbations (RMPs) has been ...

Iop Publishing Ltd2015