PhD position in Mechanical Behaviour of Transformer Insulation under Dynamic Loading

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NTNU is a broad-based university with a technical-scientific profile and a focus in professional education. The university is located in three cities with headquarters in Trondheim.

At NTNU, 9,000 employees and 43,000 students work to create knowledge for a better world.

You will find more information about working at NTNU and the application process here.

   

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About the position

Are you motivated to take a step towards a doctorate and open up exciting career opportunities? Do you have a background in electrical engineering, physics, chemistry, or materials science, and are you interested in working on an important issue related to electrification and the continued reliability of the power grid? As a PhD candidate with us, you will work toward your doctorate while gaining valuable experience that qualifies you for a career in higher education and research, both in and outside academia. 

The Department of Electric Energy (IEL) at NTNU is seeking a highly motivated candidate for a  full-time (100%) PhD position for 3 years as part of the project ClampIT. You will join the research group High Voltage Technology at IEL, where we foster an open, inclusive, and collaborative working environment.

Our work environment is defined by its friendly and supportive atmosphere, with regular gatherings such as professional meetings within the research group, weekly colloquia, shared lunches, and “Friday coffee” sessions to end the week. These formal and informal events offer opportunities to share ideas, celebrate milestones, and build relationships. PhD candidates also organize social activities open to everyone interested, fostering a welcoming and inclusive community.

Your immediate Line Manager will be the Head of Department.

About the project

Power transformers are essential for the stability and reliability of the electrical grid. As the grid evolves with renewable energy integration, high-power EV charging, and increasingly dynamic load patterns, transformers are exposed to new mechanical and thermal stresses. These stresses accelerate ageing of insulation materials and can reduce the clamping forces that keep transformer windings securely in place. Loss of clamping force increases the risk of winding deformation and short-circuit failures. While thermal ageing of insulation has been studied extensively, the long-term evolution of clamping forces under dynamic conditions remains poorly understood. Gaining knowledge in this area is crucial for safe operation, extended transformer lifetime, and improved security of electricity supply.

This PhD position is part of the larger research project KSP ClampIT – Clamping forces in Transformers: Online monitoring and predictive modelling. ClampIT builds on the experience from the DynaLoad project and brings together a strong consortium covering the entire transformer value chain, including:

• Sensor and material suppliers: COMEM, Weidmann
• Transformer manufacturers: Siemens Energy, Hitachi Energy, Kolektor Etra
• Utilities and grid operators: Statnett, Statkraft, Elvia, Scottish Power Energy Networks (SPEN), National Grid
• Research partners: SINTEF Energi, NTNU, KTH

The project aims to advance knowledge on clamping force evolution through experimental studies, sensor-based monitoring, and numerical modelling, laying the foundation for improved transformer design standards and predictive maintenance strategies.

The PhD project will focus on how the mechanical properties of transformer insulation materials—such as cellulose-based pressboard and kraft paper—change under varying temperature, moisture, and ageing conditions. The work will include:

• Experimental characterization of viscoelastic and viscoplastic behaviour under slow thermal cycles and rapid transient stresses (e.g., short circuits and inrush currents).
• Accelerated ageing experiments under compression to study long-term deformation and material degradation.
• Analysis of fast deformation behaviour during electromechanical stresses using advanced mechanical test setups.
• Numerical simulations of short and long term deformation of oil impregnated paper insulation under dynamic loading. 

The results will provide essential input for improving transformer design standards and predictive models for clamping force evolution, contributing to safer and more reliable power systems.

The main supervisor will be Professor Øystein Hestad, with Dr. Henrik Enoksen as co-supervisor. 

Duties of the position

• Carry out research of high quality within the framework described above
• Participate in activities of the research group High Voltage Technology (HVT)
• Complete academic training consisting of coursework corresponding to a minimum of 30 ECTS
• Contribute to publications in relevant journals and to popular science dissemination
• Participate in international activities such as conferences and/or research stays at foreign educational institutions 

Career-enhancing work, which is in addition to the research project and doctoral education, may be offered to a candidate who demonstrates clear motivation and ability for such work, and if the Department determines there is a need. Examples of career-enhancing work include, but are not limited to, contributing to teaching, laboratory and exercise teaching, supervision, and examination work within the employee's areas of competence. 

Be prepared for changes to your work duties after employment.

Required selection criteria

• You must have a relevant Master's degree in electric power engineering, physics, physical chemistry, material science, or equivalent. Your course of study must correspond to a five-year Norwegian course, where 120 credits have been obtained at master's level. Master’s students may apply, but the master’s degree must be obtained and documented prior to starting the position, and no later than autumn 2026.
• You must have a strong academic background from your previous studies and have an average grade from your Master's degree study, or equivalent education, which is equal to B or better compared to NTNU's grading scale. If you do not have letter grades from previous studies, you must have an equally good academic foundation. If you have a weaker grade background, you may be considered if you can document that you are particularly suitable for a PhD education, i.e., by having relevant work experience and/or published/publishable scientific papers.
• You must meet the requirements for admission to the Faculty's Doctoral Programme.
• You must have English language skills, both written and spoken, corresponding to the scale B2 in the Common European Framework of Reference for Languages (CEFR). Applicants who are not native English speakers are encouraged to document their English language proficiency. This can be done through an approved English language test. One of the following test scores could be documented for this purpose: 
  • TOEFL internet-based test (iBT) - Score equivalent to the B2 level: 79 - 101. 
  • IELTS - Score equivalent to the B2 level: 5.5 - 6.0 
  • Cambridge English - Score equivalent to the B2 level: 160 - 179.

Further assessment of both written and oral English language skills, as well as the ability to communicate fluently, will be conducted throughout the selection process and during any interviews for all applicants.

PLEASE NOTE: For detailed information about what the application must contain, see paragraph “About the application”.

The appointment is to be made in accordance with NTNUs guidelines for recruitment positions and Regulations for the degrees philosophiae doctor (ph.d.) and philosophiae doctor (ph.d.) in artistic development work at the Norwegian University of Science and Technology (NTNU)for general criteria for the position.

Preferred selection criteria

• Work and/or research experience in high voltage insulation technology and degradation/ageing of insulation materials is deemed advantageous.   
• Experience with numerical simulations (e.g., Finite Element, Finite volume, and other techniques) and programming (e.g., Python and MATLAB) is deemed advantageous.  
• Experience with material characterization (thermal and mechanical) of polymeric materials is deemed advantageous.
• English language skills, both written and spoken, corresponding to the scale C1 in the Common European Framework of Reference for Languages (CEFR). See which scores are equivalent to the C1 level here.

Personal characteristics

To complete a doctoral degree (PhD), the candidate is expected to: 

• demonstrate strong motivation, curiosity, and a learning-oriented mindset
• work independently, take initiative, and maintain good structure and discipline in their work
• communicate effectively and collaborate well with supervisors and peers
• show resilience and work constructively when facing challenges or setbacks
• demonstrate integrity and a strong sense of responsibility in their research conduct

Emphasis will be placed on personal qualities.

We offer

• An exciting job with an important mission in society
• Developing tasks in a strong and international professional environment
• Follow-up during the PhD period
• Open and inclusive working environment with committed colleagues
• Social activities organized by PhD students 
• Weekly social gathering on Fridays (Friday coffee)
• Working capital that can be used to implement the project
• Mentor programme as a new employee at NTNU
• Favorable terms as a member of the Norwegian Public Service Pension Fund (SPK) 
• Free Norwegian language training at a basic level (A2)

As a PhD Candidate at NTNU, you will have access to employee benefits.

Diversity

Diversity is a strength, and at NTNU, we aim to be an employer that reflects the diversity in society and that makes use of the potential of the population's collective skills. Our vision is Knowledge for a better world, and our values are creative, critical, constructive, and respectful. We believe that an organization that is equal, diverse, and gender-balanced is essential for us to achieve our goals. 

We strive to attract employees with different skills, life experiences, and perspectives to contribute to even better problem solving of our societal mission in research and education. 

If you think this position is relevant and interesting, we encourage you to apply, regardless of gender, functional ability, and cultural background, or whether you have been out of work for a period of time.

At NTNU we want to increase the proportion of women in scientific positions. We have a number of measures to promote equality. 

Salary and conditions

In the position of PhD Candidate, code 1017, your gross salary will normally be NOK 550 800 per annum, depending on qualifications and seniority. A 2% statutory contribution to the State Pension Fund is deducted from the salary. 

The employment period for the doctoral work is 3 years, with the possibility of an additional 3 to 12 months of employment related to career-enhancing activities.

The option for career-enhancing work may be offered to a candidate who has clear motivation and ability for such work, and if the Department deems it necessary. This will be clarified with the candidate during and after any interview. 

If you cannot document skills in Norwegian, Swedish, or Danish at level A2 upon employment, NTNU offers the opportunity to take Norwegian courses corresponding to at least 15 credits. NTNU will facilitate this. 

For employment as a PhD Candidate, it is a prerequisite that you gain admission to the PhD programme in Electric Power Engineering within three months of your employment contract start date, and that you participate in an organized doctoral programme throughout the period of employment.

The position is conditional on external funding.

The preferred start date for the position is summer or early autumn 2026.

As an employee at NTNU, it is important that you keep yourself up to date with academic and organizational changes and adapt to them.

For the necessary professional and social interaction, it is a prerequisite that you are physically present and available to the institution on a daily basis.

The appointment is carried out in accordance with the principles of the State Employees Act, and Export control (legislation that regulates the export of knowledge, technology and services). Candidates who, after assessment of the application and attachments, are considered to be in conflict with the criteria in the latter act, will not be able to be employed.

About the application

The attachments (including a description of your scientific work) must accompany the application as these documents form the basis of the application assessment. The documents must be in Norwegian/a Scandinavian language or English. 

Please note: the application will only be assessed on the basis of the information we have received by the application deadline. Therefore, make sure that your application clearly shows how your skills and experience meet the criteria described above. The application and all attachments must be sent electronically via Jobbnorge.no. If you are invited to an interview, you must bring certified copies of certificates and diplomas upon request.

The application must include:

• A cover letter where the applicant explains personal motivation, briefly summarizes scientific work, and describes how their background is a good fit (400 words/1 page).
• Project outline containing proposals for an overall description of research questions, theoretical perspectives, methodological design for the project, and progress plan (maximum 1500 words/4 pages, including references). This proposal shall neither be deemed final nor binding for the project.
• CV.
• If you have testimonials of work experience, submit them.
• Transcripts and diplomas for Bachelor's and Master's degrees. If you have not yet completed your Master's thesis, you must provide confirmation of your estimated submission date for the Master's thesis, or confirmation that your Master's thesis has been submitted.
  • Applicants from universities outside Norway are asked to provide a diploma supplement or similar document that details the study program and grading system. Also, see the specific documentation requirements for education obtained outside Norway, applicable to certain regions or countries, here.  
• A copy of the Master's thesis. If you have recently submitted your Master's thesis, you are encouraged to include a draft of the thesis. Documentation of a completed Master's degree must be provided before assuming the position. 
• If you have publications or other relevant research work, submit them.
• You are encouraged to include documentation of English language proficiency if you are not a native speaker of English. 
• Name and contact information of three referees.

If all, or parts, of your education has been taken abroad, we also ask you to attach documentation of the scope and quality of your entire education, both Bachelor's and Master's education, in addition to other higher education. If your institution uses “diploma supplement” (normal for most European institutions), you must attach this. A description of the documentation required can also be found here. If you already have a statement from Norwegian Directorate for Higher Education and Skills (HK-dir), please attach this as well.

Joint work will be considered. If it is difficult to identify your contribution to joint work, you must attach a brief description of your participation.

When assessing the best qualified, we emphasize necessary qualifications such as education, experience and personal suitability. Motivation for the position, ambitions, and potential for research will also count when assessing the candidates.

NTNU recognizes a wide range of academic contributions and has committed itself to The San Francisco Declaration on Research Assessment and CoARA (responsible assessment of research and recognition of a greater breadth of academic contributions in accordance with NTNU's social mission).

Aptitude and personality tests

We use aptitude and personality tests to evaluate candidates’ characteristics, abilities, and suitability for the position. These tests help ensure a fair and objective evaluation of all candidates and support us in identifying the most qualified person for the role.

General information

A public list of applicants with name, age, job title and municipality of residence is prepared after the application deadline. If you wish to be exempt from entry on the public applicant list, this must be justified. Assessment will be made in accordance with current legislation. You will be notified if the exemption is not granted.

If you think this position looks interesting and in line with your qualifications, you are welcome to apply.

If you have any questions about the position, please contact Professor Øystein Hestad by email at oystein.hestad@ntnu.no. 

If you have any questions about the recruitment process, please contact HR consultant Sven Robert Storø by email at sven.r.storo@ntnu.no. 

Application deadline: 26.01.2025

For practical information about working at NTNU, please visit this webpage. 

The city of Trondheim is a modern European city with a rich cultural scene. Trondheim is the tech capital of Norway with a population of 200,000. The Norwegian welfare state, including healthcare, schools, kindergartens and overall equality, is probably the best of its kind in the world. Professional subsidized day-care for children is easily available. Furthermore, Trondheim offers great opportunities for education (including international schools) and possibilities to enjoy nature, culture and family life and has low crime rates and clean air quality.