/Aurélie Flégeo

About Aurélie Flégeo

This author has not yet filled in any details.
So far Aurélie Flégeo has created 393 blog entries.

SuperGrid Institute is working towards the EU’s 32% renewable energy goal by contributing to XFLEX HYDRO

2019-12-10T16:30:36+01:00December 10th, 2019|Press release, Stabilization & Storage|

The XFLEX HYDRO project was launched today, the 10th of December, during the United Nations climate change conference (COP25) in Madrid, Spain. This major project, led by a consortium of 19 members, will play an important role in helping the EU reach its target of producing 32% of its energy from renewable resources by 2030, by demonstrating how innovative hydropower technologies can ensure the safety and flexibility of the power system.

SuperGrid Institute’s “turbine type” readiness conclusions

2019-12-02T16:16:55+01:00December 2nd, 2019|Stabilization & Storage|

How can we reduce the “S-Shaped” characteristics (stability) of a hydraulic turbine while maintaining its high performance? This spring, SuperGrid Institute completed several months of testing on different turbine designs for Pumped Storage Power Plants (PSPP). This promising and extensive research, which aims to improve power network services (supply security, flexibility, efficiency, etc.), has helped us better understand the physical phenomena and water flow that take place within turbines. It has also enabled us to corroborate our Computational Fluid Dynamics (CFD) simulation tools. A patent application was filed in September 2019 on this new technology.

SuperGrid Institute’s “Technical days”: an event dedicated to our industrial shareholders

2019-11-22T09:48:26+01:00November 22nd, 2019|Event|

SuperGrid Institute has held its first ever ‘Technical days’ event! Dedicated to our industrial shareholders, this event was organised to facilitate exchange and to allow us to better adapt our roadmap to the industry’s tangible needs. These two exciting days of workshops, discussions and networking have bolstered our belief in the importance of our mission to shape tomorrow’s HV & MV power transmission grids.

Design and validation tests of 320kV HVDC GIL/GIS

2019-11-22T11:15:42+01:00November 21st, 2019|High Voltage Substation Equipment, Publications|

This paper gives an overview of electrical DC phenomena in GIL/GIS, the influence of insulating properties of SF6 and filled epoxy resin, and design of new support insulator for 320kV HVDC GIL/GIS. The busbar system including the insulator was designed not only to satisfy all standard requirements such as mechanical, temperature rise, heating cycle performance but also particular requirements for HVDC applications such as superimposed impulse tests. Finally and for the first time at actual scale, type test according to CIGRE JWG D1/B3.57 was conducted in EDF R&D Les Renardières laboratory to verify the design and insulating performance of the 320kV HVDC GIL/GIS system. The satisfactory results allow to confirm the high technology readiness level of HVDC GIL/GIS.

Phd Raphael CHASSAGNOUX “Dielectric study of liquid and boiling nitrogen – Application to a superconducting fault current limiter”

2019-11-15T15:23:07+01:00November 14th, 2019|High Voltage Substation Equipment, Phd|

The increasing number of interconnections in electrical networks and the massive integration of renewable energies nowadays comes with an increase of short circuit currents, and more constraints on high voltage circuit breaker during the current clearance. To solve this problem, a solution consists in inserting a fault current limiting device on electrical lines. Among the available technologies, the superconducting fault current limiter is ideal from the perspective of transmission system operator. However the design of this device is non-trivial, especially the electrical insulation, which is very specific to this apparatus: electrical insulation in a cryogenic environment (liquid nitrogen at - 196°C), superconducting tapes inducing electric field reinforcement, and strong transient heating generating numerous vapor bubbles.

Phd Alexis FOUINEAU “Medium Frequency Transformers design methodologies for high voltage grids and railway grids”

2019-11-15T15:20:17+01:00November 13th, 2019|High Voltage Substation Equipment, Phd|

Medium Frequency Transformers (MFT) are an innovative technology compared to low frequency transformers, with the promise of reduced volume and increased efficiency. This PhD thesis focuses in particular on their design for high voltage, high power applications, such as high voltage and medium voltage DC networks, as well as railway networks. In these applications, MFTs are used in converters that can generate specific constraints to be taken into account during their design: non-sinusoidal signals, polarization voltage, target inductance values.

A DC voltage source for long term GIS testing designed by SuperGrid Institute

2019-11-07T17:32:54+01:00October 29th, 2019|High Voltage Substation Equipment|

As part of its research, SuperGrid Institute studies the phenomena of partial discharge under DC voltage. Environmental issues emphasised in the European project PROMOTioN encourage the exploration for possible replacement of SF6 gas and remains a strong component of the study at SuperGrid Institute.

NPC assessment in insulated DC/DC converter topologies using SiC MOSFETs for Power Electronic Traction Transformer

2019-10-22T11:34:14+01:00October 24th, 2019|Power Electronics & Converters, Publications|

Power electronic traction transformers (PETT) are multilevel AC/DC on-board converters, studied for railway applications to replace traditional solution with low frequency transformers. This paper focuses on the insulated DC/DC converter in a PETT. Three variants of resonant single active bridges (R-SAB) with 3-level NPC primaries are optimised to maximise the efficiency, under mass and dimension constraints. They are sized and compared for a 2 MW PETT on a 15 kV/16.7 Hz railway infrastructure, using 3.3 kV SiC MOSFETs and nanocrystalline C-core transformers with cast resin insulation and forced air cooling. The highest efficiency at nominal power, 99.17 %, is reached for a configuration with a 3-level full bridge NPC primary, a 2-level full bridge secondary, and a 32.1 L/49.1 kg transformer operating at 6 kHz.

The renewables integration via HVDC grids

2019-10-28T08:59:10+01:00October 22nd, 2019|Supergrid Architecture & Systems|

The large-scale integration of renewable electricity generation poses both structural, economic and management challenges. Among the major challenges, one can note the grid integration and the routing of this energy from the production units to the consumption poles. Major issues have to be faced like insufficient transmission capability, inertia reduction, stability margins mitigation. The HVDC is not a new idea but it can provide some interesting answers to these challenges. The keynote will list the locks and how they can be addressed by the HVDC grid. Finally, the underlying scientific issues will be discussed.

Electric field computation for HVDC GIS/GIL spacer under superimposed impulse conditions

2019-10-25T11:55:04+01:00October 21st, 2019|High Voltage Substation Equipment, Publications|

This paper evidences the influence of different parameters on the electric field on DC spacers in GIS/GIL and thus their dielectric withstand under S/IMP tests. A notable difference in term of electric field can be observed in function of impulse polarity, load condition (with/without heating current) and insulating material’s properties. For example, an overstress of 0.3pu was obtained on spacer’s surface in case of superimposed impulse test with opposite impulse polarity, high load condition and high leakage current in gas. Contrary to AC system where the simple LI tests were enough, S/IMP tests with both impulse polarity, ZL and HL conditions are mandatory to verify the insulating performance of HVDC GIS/GIL spacer. This paper gives a better understanding of the electric field distribution in HVDC GIS/GIL and helps for the design and tests