An experimental study of breakdown and pre-breakdown phenomena in liquid nitrogen (LN2) is performed in this paper, in order to provide useful knowledge for the design of high voltage superconducting systems.
This paper proposes a novel pole-to-ground fault protection strategy for HVDC grids under symmetrical monopolar configuration employing low-speed DC breakers and pole rebalancing reactor (PRR) located at AC side to manage the rebalancing of the pole voltages. The first part of the paper is dedicated to the detailed description of the primary and backup protection sequences. In the second part, the proposed concept is validated through EMT simulations performed on a 4-terminal HVDC grid.
The present paper aims at describing the measurement methods applied to mock-up cables in order to evaluate their dielectrics. The focus is on leakage current and temperature measurements together with the processing based upon them to assist in the selection of the more appropriate material.
Effect of the Surge Arrester Configuration in MMC-HVDC Systems under DC and Converter Fault Conditions
Different surge arrester configurations are studied for a modular multilevel converter (MMC) in a symmetrical monopole configuration. Each configuration is analyzed under fault conditions including DC side faults and faults inside the converter station. The configurations considered are compared in terms of overvoltages, current levels and energy dissipation. It is found that the selection of the surge arrester parameters does not only depend on the overvoltage levels of the equipment, but also on the surge arrester configuration considered. The action of the surge arresters could result in higher longitudinal withstand voltage requirements of the arm reactors. Furthermore, special attention shall also be given to the possible low inductance loops created by the conduction of the arresters during a transient event.
Every year, the Auvergne-Rhône-Alpes region organises the Mobility Challenge, an event that promotes using alternative modes of transport to get to work, other than by private car. As energy transition is at the heart of SuperGrid Institute’s actions and our employees’ beliefs, this Tuesday the 4th of June we decided to take up the challenge! Here’s a quick recap of this fun & environmentally friendly event that we took part in as a company.
Comparaison de mesures de conductivité obtenues par spectroscopie diélectrique et mesure de courant sous tension continue sur une résine époxy
De par sa facilité d’utilisation et sa capacité à isoler la permittivité complexe représentant les pertes dans un matériau tout en faisant un balayage fréquentiel, la spectroscopie diélectrique semble être une méthode de choix pour obtenir la valeur de conductivité ohmique d’un matériau. Cette méthode pourrait permettre de s’affranchir des temps conséquents de stabilisation généralement associés aux mesures de conductivité issues de courbes courant-tension effectuées suivant la norme IEC 62631-3. Par l’intermédiaire d’une comparaison entre ces 2 méthodes, les auteurs vont revenir sur les limites de chacune d’entre elle.
SuperGrid Institute is proud to have been an active participant in the PROMOTioN project since 2016. This project is part of the European Union’s Horizon 2020 program and is made up of several work packages (WP) that share a common aim: developing meshed HVDC offshore grids that are both cost effective and reliable, through technological innovation. SuperGrid Institute is an active member of several Work Packages, including WP9 whose objective is to develop fault clearing strategies using Hardware-in-the-Loop (HIL) real-time simulation (RTS).
This paper proposes an in-depth analysis from the control point of view of dynamic models of a Modular Multilevel Converter (MMC) for high-voltage direct current (HVDC) application. Firstly, a generic method of analysis is presented for a natural arm-level state-space model. Its structural analysis highlights the decoupled nature of the MMC. Secondly, the well-known sum and difference of the upper and lower arm state and control variables is considered to obtain a (S/D) model. This transformation leads to a coupling between state and control variables and to an increase of the system complexity. Using the analysis results of the natural model and the (S/D) model, an original arm-modular control is finally proposed. The simulation results show the effectiveness of the proposed control, which is simpler to design compared to a conventional (S/D) control.
This week, SuperGrid Institute participated as an official sponsor of the 8th edition of InnoGrid2020+, the innovative power conference co-organized by ENTSO-E and E.DSO.
This year, for the first time our presence at PCIM Europe 2019, was noticeable with our stand from 6th to 9th May. At the conference, and as power electronics is at the heart of our innovations, SuperGrid Institute was invited to present during the « Smart Transformers » special session.