Internship – State of the art converters for PSP (F/M)

SuperGrid Institute

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Posted 4 months ago

SuperGrid Institute brings together 180 employees, of 28 different nationalities who work together within a dynamic environment in the city of Lyon. As an independent research and innovation center, we are dedicated to developing technologies for the future power transmission system, the “supergrid”, including HVDC & MVDC technologies.

As a multi-disciplinary research center with advanced simulation capabilities & multiple test platforms, including numerous associated laboratories, SuperGrid Institute uses its comprehensive expertise to provide a wide range of services and solutions to support our customers in developing power systems, equipment and components. We specialise in system architecture and work on ensuring network security and stability while allowing for the integration of intermittent renewable energy sources. Find out more by visiting our website: www.supergrid-institute.com

General Context

“Pump Storage Plants (PSP) are a special type of hydroelectric facility. Composed of two basins located at different altitudes, they store energy by pumping water from the lower basin to the upper basin when electricity demand is low (and the price of electricity low). When electricity demand increases (as does the price of electricity), they restore electricity to the grid by turbining water from the upper basin. Thanks to their storage function, these installations help to maintain the balance between production and consumption on the electricity grid, while limiting production costs during consumption peaks. Energy transfer by hydraulic pumping is the most mature technique for stationary energy storage today.”[1]

In a context of massive integration of means of production based on renewable energies, these installations are called to play an increasingly important role in the management of the grid. Indeed, their flexibility (storage / production) makes it possible to solve the problem of the intermittency of renewable energy sources and not to lose this energy produced in the absence of consumption.

Conventional PSP are fixed speed: they allow a variation of the power in turbine mode but not while pumping. Consequently, during pumping, they cannot be used to balance production and consumption on the network. This is why it is interesting to design PSP with variable speed by inserting a converter between the network and the rotating machine. This converter also makes it possible to obtain a better pumping efficiency and a greater dynamic in power regulation [2].

Given the power and the current rating required, the preferred component so far has been the thyristor, used in a topology called cyclo-converter. This converter intrinsically consumes reactive power and a compensation for this energy must be carried out. Thanks to new, high-rating components such as the IGCT or the IGBT press pack, so-called VSC (voltage source inverter) topologies are possible. They have the advantage on the cyclo-converter of controlling their reactive power, of being more flexible in the event of a network fault and of allowing the machine to be started from standstill [3].

References :

[1] :        https://www.connaissancedesenergies.org/fiche-pedagogique/hydroelectricite-stations-de-transfert-d-energie-par-pompage-step

[2] :        https://www.researchgate.net/publication/329268493_CONVERTING_CONVENTIONAL_PUMPED-STORAGE_PLANTS_TO_VARIABLE_SPEED

[3] :        https://www.researchgate.net/publication/241162779_Next_generation_variable_speed_pump-storage_power_stations

Objectives / Missions

The objective of the internship is to realize a state of the art of energy conversion solutions used in variable speed PSP.

Integrated into the POWER ELECTRONICS & CONVERTERS program team and with the support from the POWER STORAGE BALANCING program, the intern will be responsible for:

  • Identify and analyze the energy conversion solutions used / usable in variable speed PSP (IEEE revue and conference papers, manufacturers documents, patents, etc.)
  • Identify the major players, industrial and academic
  • Outline the advantages of variable speed and indicate the limits of the power variation (including hydraulic constraints)
  • Identify the types of rotating machines used
  • Propose Key Performance Indicator to compare topologies with each other
  • Determine the grid ancillary services in which variable speed STEPs can participate
  • Find the requirements that these converters must meet
  • List and explain the types of faults to be considered
  • Propose and set up an approach to know the environment (follow-up  of major players, information on past / current / future projects, market trends)
  • Identify European research projects on the subject (past / present / in the process of being set up)
  • Set up a technical watch activity on the subject (IEEE alert, information flow, patent alert)
  • Depending on the progress, modeling of the converter and of the rotating machine using Simulink

Candidate Profile

Master or engineering school student in the last year of his/her studies. The required skills for this internship research topic are good knowledge in electrical engineering, power conversion and rotating machine, modelling and control.

He/she must be curious, autonomous, rigorous, proactive and have the analytical spirit. Fluency in English and French is essential.

Other information

The application has to include the internship title, candidate name, CV and the most recent marks. Applications should be sent to the following address: internship@supergrid-institute.com.

SuperGrid Institute is an equal opportunities employer. We respect and value the diversity of our employees, their backgrounds and their professional experience. We believe in equality and take affirmative action to ensure that discrimination has no place in our recruitment process nor our company.

Job Features

Job CategoryInternship
Contract TypeInternship
Duration6 months
Start DateSeptember 2020

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