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Phd Paolo ERRANTE “Liquid Spray Injection inside the expansion volume of a CO2 High Voltage Circuit Breaker”

2020-02-12T10:22:27+01:00February 5th, 2020|High Voltage Substation Equipment, Phd|

In the framework of the research activities of the High Voltage Substation Equipment program of SuperGrid, it has been proposed to introduce such species by means of an evaporative liquid spray. The interaction between injected droplets and the mixture of hot gases successively flowing into the chamber and vented outside the chamber during the mechanical separation of the electric contacts should allow spray evaporation and transport of the modified gas mixture towards the arc region.

Phd Majed Eddine MOUSTAID “Experimental development of a thermosiphon loop for thermal regulation of power electronic devices”

2020-01-16T16:25:42+01:00January 16th, 2020|Phd, Power Electronics & Converters|

The work of this thesis focuses on the experimental development of a passive and biphasic cooling system to cool down power electronics. Some of those modules are mean voltage power converters developed by Supergrid Institute. Some constraints have been imposed upstream to this project. While some limitations are of the technological nature, other constraints are related mainly to the environmental and biological aspects. The first part of this thesis was to find a suitable cooling system that could be adapted to the project specifications. After some research, we decided to build a loop thermosiphon filled with NOVEC 649.

Phd Ragavendran RAMACHANDRAN “Control and Power Management of an Offshore Wind Power Plant with a Diode Rectifier based HVDC Transmission”

2019-12-18T16:53:03+01:00December 16th, 2019|Phd, Supergrid Architecture & Systems|

 Energy Transition for a more sustainable world is now the priority in societies. Towards this objective, especially in Europe, the offshore wind energy development has been relatively rapid. For Offshore Wind Power Plants (OWPP) farther from the shore (50 km and beyond) Voltage Source Converter (VSC) based High Voltage DC (HVDC) Transmission has become the prominent solution. Replacement of the offshore VSC station by multiple Diode Rectifier Units (DRUs) led to a cheaper, more compact and robust solution. This thesis focusses on various technological and scientific problems involved in the control system of the Offshore Wind power Plant with Diode Rectifier (DR) based HVDC transmission. These challenges are first reviewed in detail along with the state of the art. Then, based on the system dynamics, a grid forming control scheme is proposed by using the P-V and Q-f droop relationships, with a solution for the synchronization of the wind generators. Moreover, some of the selected control solutions in the literature for this topology are reviewed, compared and assessed by using time domain simulations of a study case. Following this, the different solutions for black start of the offshore AC system are analyzed from the available literature and they are compared using the relevant qualitative criteria. The various faults in the offshore system are then analyzed and the above designed grid forming control scheme is extended with Fault Ride through (FRT) capability, for offshore AC grid faults. Finally, a brief analysis is done on the challenges for the integration of this OWPP topology into a Multi Terminal DC (MTDC) network. 

Phd Juan PAEZ “HVDC Converters for the interconnection of HVDC grids”

2019-12-13T15:15:25+01:00December 13th, 2019|Phd, Power Electronics & Converters|

In order to include large-scale renewable sources into the electrical system and to transport high amounts of energy through long distances, the actual AC grid must be upgraded. HVDC transmission grids appear as a promising solution to upgrade the system and answer correctly the future needs and requirements. The development of such grids can be done following two different approaches. For one side, a DC system designed totally from zero following a standardization of HVDC technology, and for the other side, an incremental evolution using the existing HVDC lines. The second approach seems more reasonable due to the reutilization of infrastructure, the inconvenient is that the technology used on each existing line is different. Thus, their interconnection will require DC¬DC converters as interface elements. These structures allow the interconnection of different HVDC schemes and offer more functionalities than only DC voltage adaptation like power flow control and protection.

Phd Thibaut LEFORT “Epoxy/ionic liquid networks with and without anhydride: study of polymerization mechanisms and dielectric properties”

2019-12-17T09:08:48+01:00December 12th, 2019|High Voltage Substation Equipment, Phd|

Thursday 12/12/2019, Thibaut Lefort has obtained the title of Doctor of Materials of Lyon university after a high quality viva. Hence, the thesis jury has strongly encouraged him to candidate for a Ph.D award granted by INSA in the energy category.

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.

Phd Guilherme DANTAS DE FREITAS “Development of a methodology for DC grid protection strategies comparison”

2019-10-22T18:15:05+02:00October 18th, 2019|Phd, Supergrid Architecture & Systems|

High Voltage Direct Current (HVDC) grids are considered a promising solution for problems faced by nowadays power system such as: lines congestion, integration of large amounts of renewable power and enhancement of AC system stability. Among the challenges in the deployment of a HVDC meshed grid, the protection of these grids is regarded as one of the most critical. The protection of HVDC grid is challenging not only because the swift transients and fault currents without zero-crossing, but also due to the impact a DC faults can have on the AC system. Several propositions for HVDC grids protection strategies can be found in literature...

Phd Priscillia DANIEL “Electrical properties study of cross-linked polyethylene insulated cables in presence of gaseous cavities aged under DC or DC with harmonic voltages”

2019-07-09T16:00:23+02:00July 5th, 2019|High Voltage Substation Equipment, HVDC Cable Systems, Phd|

This study aims to examine possible impact of these harmonics in presence of microcavities. Depending on their size and on the electrical field, partial discharges (PD) can occur in these microcavities. Two types of cables have been aged: a medium voltage AC (MVAC) cable with millimetric cavities induced artificially and a model cable with an HVDC XLPE grade.

PhD Loriane DESMARS “Study of electrical and thermal properties of epoxy-anhydride composite materials for high voltage insulation”

2019-04-04T11:12:50+02:00April 2nd, 2019|High Voltage Substation Equipment, HVDC Cable Systems, Phd|

The work presented in this manuscript has been motivated by the necessity to develop more efficient electrical insulating materials compared to commercially available ones. An epoxy-anhydride matrix filled with micron sized alumina, often used to produce GIS solid insulators, has been used as a reference for this study.