PhD position – “Control of HVDC transmission systems for the reliable operation of hybrid AC/DC systems with high integration of power electronics-based devices”

Posted 1 month 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 centre, we are dedicated to developing technologies for the future power transmission system, the “SuperGrid”, including HVDC & MVDC technologies.

As a multi-disciplinary research centre 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 specialize 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

Integration of large amount of renewable energy sources (RES) (e.g., offshore wind, PV) and energy market integration are two of the main drivers for the future development of the pan-European power grid. This will require a reinforcement of the transmission grid to make it able to transport large amount of power over long distances from generation areas to load areas. Extended High-Voltage Direct Current (HVDC) grids, in Point-to-point (PtP) or Multi-Terminal (MTDC) configuration, covering large distances, are considered to be the preferable solution for the reinforcement of the grid. Those systems will be evolving from simple point to point and radial structures to complex meshed ones. To achieve their development, it is necessary to enhance their operating procedures with major challenges in control and protection.

The development of such HVDC systems together with the massive integration of RES, will result in a power system with more and more Power Electronics Interfaced Devices (PEIDs), where AC/DC converters (e.g., VSCs or Modular Multi-level Converters (MMC)) are a key component and have a significant impact on the integrated AC/DC transmission system behaviour. Such AC/DC power systems with high integration of RES will be possible only if it can be demonstrated that they are economically viable and that their resilience and reliability can be assured under any realistic condition (normal operation and disturbed situation).

Position Context

The Horizon Europe HVDC-Wise project proposes solutions to foster the development of large HVDC grid infrastructures able to bring benefits in terms of resilience and reliability to the existing electrical system and capable of integrating the forthcoming large amount of renewable energy.  To this end, The HVDC-Wise project aims to: 1) Propose a set of technological solutions in terms of HVDC architecture and operational algorithms (control and protection) to harness the full potential of HVDC to increase the resilience of the AC/DC system. 2) Provide the necessary tools and methodologies to analyse the reliability and resilience levels of AC/DC systems integrating the proposed HVDC solutions, allowing their design. 3) Validate the proposed solutions on realistic use cases using the developed tools.

The PhD topic described in the following sections focuses on objective 1 and 3.

 

PhD topic description

 

Scientific context:

The ongoing electricity transition from conventional generation to power electronics-dominated one is highlighting some issues such as the reduction of inertia and the decrease of system strength. The operation of the power system under these conditions is becoming a major challenge for TSOs. As an answer to this issues, one possibility is for the grid-connected converters to use “grid-forming” controls, which have been shown to enable stable operation of grids with high integration of power electronics [1]. Indeed, some TSO will soon require converters to provide grid forming capabilities and also some pilot projects around the world have been installed in the recent years. Although much research has been done to propose grid-forming controls and to understand their behavior with respect to the power system, there are still some open questions, especially regarding high-power applications.

Scientific work:

Recent works have helped to understand the behavior of grid-forming converters under different disturbances (faults, load variations, line tripping) and have proposed to adapt the controls to enhance the capability of the converter to remain connected during and after the disturbance [2]. Most part of these studies have been carried out on simple benchmarks including one renewable source (often ideal) connected via a grid-forming converter to an infinite bus.

The proposed PhD topic will therefore focus on how the grid-forming converter, once its synchronization is assured, can help to reduce the impact of the disturbance on the surrounding AC grid; a grid with high integration of power electronics. Special emphasis will be placed on converters used in HVDC applications (either in PtP or MTDC networks) whose behavior is highly influenced by the dynamics of the DC network [3].

Therefore, the PhD candidate will propose solutions to adapt the existing grid-forming controls as to reduce the impact of different types of disturbances on the surrounding AC and DC networks. The evaluation of the propositions against different kind of disturbances (expected frequent events or high-impact low-probability events) will be done via the modeling, simulation, and analysis a hybrid AC/DC system. In a next stage, the co-existence of the grid-forming control of the converter with higher level layers of control for providing AC network services (e.g., frequency support) will be analyzed as to determine/quantify their compatibility. In a final stage, the candidate will test these propositions on industrially relevant environments (realistic use cases, either in offline simulation or in hardware-in-the loop simulation).

References

[1] Mourouvin, R., Gonzalez-Torres, J.C., Dai, J., Benchaib, A., Georges, D. and Bacha, S., 2021. Understanding the role of VSC control strategies in the limits of power electronics integration in AC grids using modal analysis. Electric Power Systems Research, 192, p.106930.

[2] Rokrok, E., Qoria, T., Bruyere, A., Francois, B. and Guillaud, X., 2021. Transient stability assessment and enhancement of grid-forming converters embedding current reference saturation as current limiting strategy. IEEE Transactions on Power Systems, 37(2), pp.1519-1531.

[3] Gonzalez–Torres, J.C., Mourouvin, R., Shinoda, K., Zama, A. and Benchaib, A., 2021, October. A simplified approach to model grid-forming controlled MMCs in power system stability studies. In 2021 IEEE PES Innovative Smart Grid Technologies Europe (ISGT Europe) (pp. 01-06). IEEE.

Candidate Profile

Engineering degree and/or Master’s degree in Electrical Engineering or in Control Engineering (or equivalent).

  • Technical skills:
    • Good skills in Modelling, analysis, and control of power systems
    • Good skills in control theory and mathematics
    • Good skills in control of power-electronics converters
    • Notions on HVDC system control and protection
  • Other skills
    • Sens of deduction, ability to work within a research team
    • Very good command of English language is a must (oral and written)
    • Ability to propose and adjust collaborative approach methodology and decision-making process
    • Ability to structure activities and planning in a pragmatic and efficient manner
    • Excellent synthesis skills.
    • Good communication and organizational skills

The application must be sent at the following address : juan-carlos.gonzalez@supergrid-institute.com and has to include the job title, candidate name, CV and the most recent marks.

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

Contract TypeCDD
Duration36 months
Start DateFrom October 2022

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