HTS cable and protection system study for UK's 275 kV transmission network

The global shift towards zero carbon emissions has led to an increased demand for electricity, (e.g., For electrification of heat, transportation, etc.). High-temperature superconductor (HTS) cables offer a high-capacity and small-footprint solution compared to traditional cable technologies, making them ideal for densely populated areas. HTS cables, however, possess different electrical characteristics compared to conventional cables. This paper presents a specific case study of a 12.9 km long 275 kV HTS cable connecting Birkenhead Substation and Lister Drive Substation in the U.K. A dynamic electrical model incorporating the varying resistance of the HTS cable was constructed. The HTS cable model was integrated into an equivalent test network, representing conditions at the target site, to analyse its behaviour and impact on conventional power system protection performance via simulation case studies. The results indicate that differential protection operates reliably, while distance protection is impacted by the varying resistance. However, the proposed HTS cable design at the specified location presents a relatively small change in HTS cable resistance. The impact on distance protection was therefore minimal and can be addressed by considering HTS properties when determining distance protection settings. The study was conducted by considering manufacturer-supplied HTS parameters, network parameters reflective of an actual location in the U.K. grid, and protection requirements specified in the U.K. grid code. The study provides valuable insights into practicality and protection strategies for reliable HTS cable operation in a real-world transmission network. The findings can inform future HTS cable designs and installations globally, as well as provide a framework for further research in this area

Design and economic analysis of 275 kV HTS cable for UK transmission network

Achieving Net Zero requires a significant increase in electricity demand for transportation, heating, and industrial sectors. However, the increase in demand poses a challenge for heavily congested urban networks. High-Temperature Superconductor (HTS) 275 kV cables offer a credible technology solution that can uprate existing cable routes up to five times higher capacity density, utilizing existing 275 kV substations and removing the need to uprate circuits to 400 kV. This paper presents a detailed technical design and cost-benefit analysis for the cable installation. The technical analysis covers location selection, power system considerations, and standards alignment. A 12.9 km long 275 kV cable has been designed using cold dielectric and three separate phases. An equivalent circuit model was built using distance and differential protection methods to study the operation during different fault scenarios. A Standard mapping exercise has been performed to understand the gaps between the HTS and conventional cables by covering seven existing standards to identify the further tests to de-risk the technology. The economic analysis by considering the full lifecycle shows HTS is the economic for the chosen location with instances where substation equipment or land expansion costs are dominant

SuperRail - Premier câble supraconducteur au monde à être installé sur un réseau ferré à usage commercial

PosterNational audienceLe réseau ferroviaire français est soumis à de nombreuses contraintes, notamment liées à l'augmentation du trafic de 60% entre 1998 et 2008 et qui devrait encore augmenter de 4 fois d'ici 2030. Pour renforcer les capacités de transport en ville tout en réduisant les pertes électriques, il peut être intéressant d'installer des câbles supraconducteurs. C’est le choix retenu par la SNCF dans le cadre du projet SuperRail, lancé en février 2022 et qui consiste en le développement, la fabrication et l'installation de câbles supraconducteurs à haute température critique (HTc) pour renforcer l'alimentation électrique de la gare Montparnasse à Paris. Deux câbles HTc de 1,5 kV-3,5 kA et 80 m de long seront installés en parallèle et reliés à la sous-station électrique de Ouest-Ceinture pour alimenter deux faisceaux de voies. Dans cet article, nous détaillerons les innovations mises en œuvre dans le cadre de ce projet, notamment : le câble supraconducteur, les terminaisons et le système de refroidissement fournissant 2 kW à 68 K. Pour finir, des études prospectives visant à améliorer davantage l’efficacité énergétique du système en optimisant ou remplaçant certains éléments seront présentées

Current status and future prospects of the SuperRail project in France

Invited talkInternational audienceToday, increasing rail traffic while ensuring continuity of service represents a major challenge for SNCF, the French rail operator. To meet this challenge, particularly in densely populated areas such as Paris, SNCF has recently launched a number of electrification projects. One aspect of these projects aims to reduce line losses in order to lower the voltage drop on the 1.5 kV rail network. Among the possible technological choices, high-temperature superconductor (HTS) cables are a promising solution.The SuperRail project, supported by the French government, will be the first installation of a HTS cable system on a commercially operated railway electric grid [1]. The project's goal is to develop, manufacture, and install an HTS DC cable system at the Montparnasse railways station in Paris. Due to the restricted space available in the city's saturated underground, the HTS technology provides the only viable solution for increasing the power supply from the railway traction substation to a group of railway tracks. This will allow for an increase in train traffic while simultaneously reducing CO2 emissions. Two 60-meter long 1.5 kV-3.5 kA HTS DC cables made of 2G conductors will be installed in parallel. They are designed to meet stringent load chart requirements and to sustain a 67 kA-200 ms short-circuit current.This paper will describe the current status of the project, as well as the selected cable and cooling system technologies. In addition, results of prospective studies on the reduction of losses in the terminations and on the advantages of using a cryo-converter, will also be discussed.[1] Arnaud Allais, Jean-Maxime Saugrain, Beate West, Nicolas Lallouet, Hervé Caron, et al.. SuperRail − World-first HTS cable to be installed on a railway network in France. IEEE Transactions on Applied Superconductivity, 2024, 34 (3), pp.4802207. ⟨10.1109/TASC.2024.3356450⟩. ⟨hal-04320346

Test results of the SuperRail HTS cable system for the French railway electric grid

PosterInternational audienceThe SuperRail project, backed by the French government, will be the first installation of a high-temperature superconducting (HTS) cable system on a commercially operated railway electric grid. The project's goal is to develop, manufacture, and install a HTS DC cable system at the Montparnasse railways station in Paris. Due to the restricted space available in the city's saturated underground, the HTS technology provides the only viable solution for increasing the power supply from the railway substation to a group of railway tracks. This will allow for an increase in train traffic while simultaneously reducing CO2 emissions. Two 80 m long 1.5 kV-3.5 kA HTS DC cables made of 2G conductors will be installed in parallel. They are designed to meet stringent load chart requirements and to sustain a 67 kA-200 ms short-circuit current. Prior to the installation at Montparnasse, a complete 35-m HTS cable type test loop was successfully installed and tested at the SNCF Vitry test facility. This system includes two terminations, one splice, and a fully automated cooling system that manages the thermal cycles between room temperature and cryogenic rated conditions

SuperRail - World-first HTS cable to be installed on a commercial railway network in France

Large scale oral sessionsInternational audienceThis paper presents the SuperRail project, launched in June 2022 and consisting in the development, the manufacturing and the installation of a high temperature superconducting HTS DC cable system. The objectives of the project are to reinforce the power supply of the Montparnasse railways station in Paris, to increase the traffic and to participate to the reduction of CO2 emission. The saturated underground in the centre of Paris does not allow to create new right of ways and only the HTS cable technology allows to carry the required power to railway tracks using the few available 100 mm ducts left. The cable system and the ancillary services have to answer to a load chart with a high level of requirements corresponding to the connection of a standard supply cell in a substation to a group of railways tracks in very constraints areas. The technologies developed have the potential to be reproduced in similar cases existing in large cities. In the case of SuperRail, two 80 m long 1.5 kV-3.5 kA HTS DC cables made of 2G conductors will be installed in parallel. They will need to sustain a 67 kA-200 ms short-circuit current. The cryogenic system to cool the HTS cables is specifically designed for this project. It is based on a Reverse Turbo-Brayton cycle providing cooling power of about 2 kW at 67 K. This system intends to ensure low maintenance during life cycle, high reliability and would be scalable for future application (unlimited to railway). Efforts are being done to reduce the losses in the 4 current leads, and to optimize the space required by the pipes for the circulation of the liquid nitrogen. In parallel, prospective studies are being carried out in order to find original solutions to replace the current leads by other systems integrating a part of the power converter and the transformer at cryogenic temperature. SuperRail is a landmark project, as it is the first time that a DC HTS cable system is installed on a commercially operated railway network

SuperRail − World-first HTS cable to be installed on a railway network in France

We would like to thank our colleagues at SNCF, Nexans, Absolut System, University Paris-Saclay and the University of Lorraine for the valuable insights they provided and the in-depth discussions we had.The SuperRail project consists in the development, manufacturing, installation and long-term operation of a high temperature superconducting (HTS) DC cable system for railway applications. The objectives of the project are to reinforce the power supply of the Montparnasse railway station in Paris, to increase the traffic and to participate to the reduction of CO2 emission. The saturated underground in the center of Paris does not allow to create new right of ways and only the HTS cable technology allows to carry the required power to railway tracks using the few available 100 mm conduits left. The HTS cable system must answer to a load chart with a high level of requirements corresponding to the connection of a substation to a set of railways tracks in very constraints areas. In the case of SuperRail, two 60-meter long 1.5 kV-3.5 kA HTS DC cables made of second-generation (2G) conductors will be installed in parallel. They need to sustain a 67 kA-200 ms short-circuit current. The cryogenic system is specifically designed for this project. It is based on a Reverse Turbo-Brayton cycle producing cooling power of about 1700 W at 67 K. This system intends to ensure low maintenance during life cycle, high reliability and would be scalable for future application (not limited to railways). In parallel, prospective studies are being carried out to simulate superconducting cables in railway networks, and to find original solutions to replace the current leads. SuperRail is a landmark project, as it is the first time that a DC HTS cable system is installed on a commercially operated railway network. The technologies developed have the potential to be reproduced in similar cases existing in large cities