Investigating the impact of subharmonics induced by inverter-based resources to enable a renewables-led future power grid

Applications are invited for a PhD studentship, to be undertaken at Imperial College London (Control and Power Research Group, Department of Electrical and Electronic Engineering). This studentship is funded by an EPSRC Industrial Doctoral Landscape Award (IDLA) and industrial partner, EDF Renewables UK&I. EDF Renewables UK&I is a major renewable energy company, with more than 14 GW of renewables projects in planning and development. With a portfolio of 42 sites across the UK, including onshore, offshore, battery and solar, EDF Renewables UK&I is providing some of the much needed new affordable, low carbon electricity in the UK. As part of the project, the student will work closely with staff at EDF and benefit from their mentoring and supervision.

The project will be supervised by Dr. Giordano Scarciotti (Imperial – Academic Supervisor), Dr James Wylie (EDF Renewables – Industrial Supervisor), and Dr Frank Tutu (EDF R&D UK – Industrial Supervisor).

Summary of Project:

The increase penetration of renewables is a vital part of the energy transition, however the growth of inverter-based resources (IBRs) such as solar and wind generation can introduce complexity and disrupt the coherency of classical generators, giving rise to unexplained phenomena. Renewable developers are facing a challenge around grid compliance when connecting renewable projects to the transmission network. Specifically, despite harmonic studies reporting no problems, subharmonics appear unexpectedly in the interconnected system. The fact that these subharmonics are not detected by the studies highlights that there is a knowledge gap between the current understanding of the power grid and the complex behaviour caused by the introduction of IBRs. Without the ability to understand and estimate harmonics at the design and procurement phases, renewable developers are having to rely on costly ad-hoc solutions, such as filters. This project aims to investigate the causes of these subharmonic phenomena, develop new models that can capture these behaviours, and potentially design control methods to alleviate their effects.

Objectives:

The objectives of the projects are:

• Explain what causes the appearance (and sudden disappearance) of subharmonic behaviours.
• Explain why these phenomena are not correctly captured by current models and simulation studies.
• Incorporate these identified causes into new harmonic studies.
• Develop control solutions to eliminate these subharmonics.
• Determine the key factors that impact grid compliance (including and beyond harmonics) and develop mitigating actions.

Novelty and Expected Outcomes:

This project addresses a critical knowledge gap in understanding and mitigating subharmonic phenomena arising from the increased penetration of IBRs into power systems. By developing advanced nonlinear modelling techniques and innovative algorithms, the project will uncover the root causes of subharmonic behaviours and integrate these insights into improved harmonic studies. Novel control solutions will be devised to eliminate subharmonics, ensuring grid compliance, and enhancing system reliability. The expected outcomes include a fundamental advancement in the theory of subharmonic behaviours, validated through realistic case studies with EDF, and practical methodologies for renewable grid connections. These contributions will help minimise financial losses for renewable developers, streamline compliance processes, and support the transition to net-zero energy systems by improving the operational stability of future grids.

Skills and Technologies:

The IDLA student will develop an in-depth understanding of large-scale nonlinear IBR models by reviewing literature and meeting with relevant experts within industry and academia. The student will investigate novel modelling techniques for large-scale multi-physics models with a focus on isolating and correcting grid sub-harmonic behaviour. The student will work closely with EDF on realistic case studies for testing the developed methods in real-world power systems.

Why Join This Project?

Joining this project offers the unique opportunity to tackle cutting-edge challenges in modelling of renewable energy integration, a critical field driving the global transition to net-zero. You will work at the forefront of power and nonlinear systems research, developing innovative solutions to address subharmonic phenomena that impact grid compliance and renewable energy deployment.

Funding:

This PhD studentship is jointly funded by the EPSRC and EDF. Only students with home fee status are eligible to apply for this studentship (Who pays home fees in England). It includes a EPSRC rate stipend of approximately £21,870 per year (tax-free) plus £4000 per year (tax-free) top-up from industry for four years, in addition to economic support (with a top-up from industry) for research expenses, travel to collaborators, conferences, and a secondment at EDF. The student should ideally be able to start on the first day of the 2025/26 academic year (27 September 2025).

Duties and responsibilities

The responsibilities include studying the relevant literature, defining the research problems based on the project descriptions, conducting independent research, regularly reporting progress and results in both oral and written format, collaborating with other team-members, and writing reports/papers of the research outcomes when appropriate. The successful candidate will be based at the Control and Power Group at Imperial College London but will have the opportunity to visit EDF to attend meetings and undertake a secondment at their premises.

Essential Requirements:

Applicants should have a first-class Master’s degree (or equivalent) in any field of engineering, physics or mathematics. The ideal candidate would also have a background in Electrical and Power Engineering, and Control Systems. They should be highly motivated individuals with a keen interest in conducting interdisciplinary research. Students must also meet the eligibility requirements for postgraduate studies at Imperial College London.

Further Information and application:

Please click HERE to apply.

Please choose Electrical and Electronic Engineering Research Program and Control and Power Research Group, then indicate Dr Giordano Scarciotti as a potential supervisor when making the application.

The application should include a covering letter (explaining your motivation, relevant background and evidence of excellence in academic studies), research statement (as understood by the candidate based on the ad) and your CV. Full guidance on the application process is available HERE. For queries regarding the application process, please contact eee.pgadmissions@imperial.ac.uk.

Closing Date: 16^th March 2025