PhD in Ageing Models and Reliability of Extruded HVDC Cables for Offshore Power

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About the job

For a position as a PhD Candidate, the goal is a completed doctoral education up to an obtained doctoral degree.

The Department of Electric Energy at NTNU has a vacancy for a full-time 100% position (3 years) as a PhD candidate within high voltage technology – Ageing Models and Reliability of Extruded HVDC Cables for Offshore Power. The prospective candidate will be part of the research group High Voltage Technology (HVT).

Extruded High Voltage Direct Current (HVDC) cable systems, a modern alternative to traditional mass-impregnated HVDC cables, offer significant advantages such as higher conductor temperatures, lower costs, and faster installation. These systems are essential for unlocking the potential of large-scale renewable energy production and enabling cross-border power transmission to meet energy-saving targets and reduce CO₂ emissions.

Despite their benefits, ensuring the long-term reliability of extruded HVDC cables remains a challenge due to the lack of established physics-based ageing models. While extruded insulation for AC cables has been successfully utilized for decades, directly transferring this knowledge to HVDC conditions is not straightforward. HVDC systems are subjected to unique thermo-electric stresses, making it critical to understand their intrinsic ageing mechanisms for accurately predicting cable lifespans, which can exceed 40 years. Additionally, contaminants from production such as scorch, cross-linking by-products, and protrusions from semiconductive screens can significantly affect insulation degradation. The impact of humidity on ageing is particularly critical, as the most reliable water barrier for subsea cables, extruded lead sheaths, is incompatible with dynamic cables required for floating offshore applications. Furthermore, the EU is expected to impose severe restrictions on the use of lead in the near future, necessitating alternative solutions, such as wet or semi-wet designs (e.g. water will slowly diffuse into the insulation material). For these alternatives to be viable, their short- and long-term effects on cable reliability under HVDC conditions must be thoroughly understood.

Without robust ageing models, conducting effective condition assessments and managing the risk of failures is difficult, potentially leading to costly repairs and system downtimes. As the adoption of extruded HVDC cable systems accelerates, there is an urgent need for comprehensive research and development to address these knowledge gaps, ensuring the reliability and resilience of HVDC transmission infrastructure.

The position is sponsored by the LowEmission Research Centre. This centre will develop new technologies and concepts for offshore energy systems, energy efficiency and integration with renewable power production technologies for application on the Norwegian Continental Shelf (NCS). The prospective candidate will be part of a project team that works in close collaboration with the LowEmission consortium. The PhD Candidate will be employed at NTNU, and the workplace will be in Trondheim, in connection with this research centre. 

The main supervisor for the PhD candidate is Professor Øystein Hestad, and co-supervisors are Professor Frank Mauseth and Dr. Torbjørn Andersen Ve (SINTEF Energy Research). 

Your immediate leader is the Head of Department. 

Duties of the position

The objective of the PhD education is to qualify for scientific research of high international standards. The PhD education has a nominal duration of three years of full-time study and includes required coursework or similar academic training comprising a minimum of 30 credits. The most important component of the PhD education is an independent scientific research project carried out under academic supervision, which results in the PhD thesis. The PhD degree is conferred based on these two elements and the doctoral examination, which consists of a trial lecture and a public defence of the scientific thesis.

The main research questions in connection to this PhD project are: 

• What are the main thermo-electric ageing mechanism for polymeric HVDC insulation under DC stresses? 
• How does humidity influence the ageing of polymeric HVDC insulation. 

To answer these research questions, NTNU’s high voltage lab and SINTEF Energy Lab will be at the candidate’s disposal. This includes setups for space charge accumulation measurements (PEA setups), climate chambers, high voltage sources, setups for dielectric response measurements (both in time and frequency domain), and setups for measuring field and temperature dependent conductivity. In addition, the national research infrastructure at Elpowerlab and NTNU NanoLab will be important assets. 

The candidate is expected to disseminate scientific findings via journal publications and international conferences, workshops, or similar events and thus take part in academic discussion in the international academic community. 

Required selection criteria

• You must have a professionally relevant background in electric power engineering, physics, physical chemistry or material science.
• Your education must correspond to a five-year Norwegian degree program, where 120 credits are obtained at master's level.
• You must have a strong academic background from your previous studies and an average grade from the master's degree program, or equivalent education, which is equal to B or better compared with NTNU's grading scale. If you do not have letter grades from previous studies, you must have an equally good academic basis. If you have a weaker grade background, you may be assessed 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 program.
• You must have Norwegian, Swedish, or Danish language skills at level A2. If you cannot document those skills upon employment, you must take Norwegian courses corresponding to at least 15 credits before the end of the employment period. The Norwegian training comes in addition to the scholarship holder's three-year doctoral work. The language requirements only apply if the candidate takes up the position from 1 August 2025 onwards.  
• You must have Norwegian, Swedish, or Danish language skills corresponding to the scale A2 in the Common European Framework of Reference for Languages (CEFR). Applicants from non-English speaking countries outside EU/EEA/Switzerland must provide preliminary documentation of English language proficiency, in terms of an approved test. One of the following test scores could be documented for this purpose:  
  • TOEFL internet-based test (iBT) — iBT enhanced score reporting is required. Your proficiency level for the overall test should correspond to a score in the range 101 – 79. Your proficiency level for each test section should correspond to at least ‘high intermediate’ level. 
  • IELTS — 7, with no section lower than 6.5 (only Academic IELTS test accepted)  
  • Cambridge English: Advanced (CAE) — 185 - 176. 

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

The appointment is to be made in accordance with Regulations on terms of employment for positions such as postdoctoral fellow, Phd candidate, research assistant and specialist candidate and Regulations concerning the degrees of Philosophiae Doctor (PhD) and Philosodophiae Doctor (PhD) in artistic research national guidelines for appointment as PhD, post doctor and research assistant 

Preferred selection criteria

• Work and/or research experience in high voltage insulation technique and degradation/ageing of polymeric insulation materials, as well as experimental experience with high voltage, is deemed advantageous. 
• Experience with numerical simulations (Finite Element, Finite volume, and other techniques), and with programming (e.g. Python and MatLab) is deemed advantageous. 

Personal characteristics

• Inquisitive, curious, and creative, i.e., eager to find new information and explore, wanting to know how and learn, and good at thinking of new ideas. 
• Self-motivated with a strong ability to work both independently, and in cooperation with others and with an interdisciplinary team, when required. 
• Structured, targeted, and solution-oriented with a strong ability to manage multiple duties simultaneously, prioritizing tasks and meeting deadlines. 
• Very good communication skills, both orally and in writing. 

Emphasis will be placed on personal and interpersonal qualities.

We offer

• exciting and stimulating tasks in a strong international academic environment
• an open and inclusive work environment with dedicated colleagues
• favourable terms in the Norwegian Public Service Pension Fund
employee benefits

Salary and conditions

As a PhD candidate (code 1017) you are normally paid from gross NOK 532 200 per annum before tax, depending on qualifications and seniority. From the salary, 2% is deducted as a contribution to the Norwegian Public Service Pension Fund.

The period of employment is 3 years.

Appointment to a PhD position requires that you are admitted to the PhD programme in Electric Power Engineering within three months of employment, and that you participate in an organized PhD programme during the employment period. 

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The engagement is to be made in accordance with the regulations in force concerning State Employees and Civil Servants, and the acts relating to Control of the Export of Strategic Goods, Services and Technology. Candidates who by assessment of the application and attachment are seen to conflict with the criteria in the latter law will be prohibited from recruitment to NTNU. After the appointment you must assume that there may be changes in the area of work.

Employment in the position requires funding. 

It is a prerequisite you can be present at and accessible to the institution at campus Trondheim on a daily basis.

About the application

The application and supporting documentation to be used as the basis for the assessment must be in English.

Publications and other scientific work must be attached to the application. Please note that your application will be considered based solely on information submitted by the application deadline. You must therefore ensure that your application clearly demonstrates how your skills and experience fulfil the criteria specified above.

The application must include: 

• A cover letter where the applicant describes personal motivation, summarizing scientific work, and how the applicant sees her/his background as suitable (1 page max)
• CV, testimonials, and certificates. 
• Transcripts and diplomas for bachelor's and master's degrees. If you have not completed the master's degree, you must submit a confirmation that the master's thesis has been submitted. Applicants from universities outside Norway are kindly requested to send a diploma supplement or a similar document, which describes in detail the study programme and grading system. See also specific documentation requirements for education obtained outside of Norway, applicable to certain regions/countries, here. 
• A copy of the master's thesis. If you recently submitted your master's thesis, you can attach a draft of the thesis. Documentation of a completed master's degree must be presented before taking up the position.
• A research proposal (2-4 pages with references), where the candidate presents her/his own ideas for the PhD work and how it can be applied, based on the project description given in this advertisement. This proposal will be neither final nor binding for the project.
• Name and contact information of three referees.
• If you have publications or other relevant research work, submit them.

Incomplete applications will not be taken into consideration. 

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. Description of the documentation required can be found here. If you already have a statement from Norwegian Directorate for Higher Education and Skills, please attach this as well.

We will take joint work into account. If it is difficult to identify your efforts in the joint work, you must enclose a short description of your participation.

In the evaluation of which candidate is best qualified, emphasis will be placed on education, experience and personal and interpersonal qualities. Motivation, ambitions, and potential will also count in the assessment of the candidates. 

NTNU is committed to following evaluation criteria for research quality according to The San Francisco Declaration on Research Assessment - DORA.

General information

Working at NTNU

NTNU believes that inclusion and diversity is our strength. We want to recruit people with different competencies, educational backgrounds, life experiences and perspectives to contribute to solving our social responsibilities within education and research. We will facilitate for our employees’ needs.

NTNU is working actively to increase the number of women employed in scientific positions and has a number of resources to promote equality. 

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The city of Trondheim is a modern European city with a rich cultural scene. Trondheim is the innovation 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.

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As an employee at NTNU, you must at all times adhere to the changes that the development in the subject entails and the organizational changes that are adopted.

A public list of applicants with name, age, job title and municipality of residence is prepared after the application deadline. If you want to reserve yourself 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 reservation is not accepted.

If you have questions about the position, please contact Professor Øystein Hestad at telephone +47 97112257 or by email oystein.hestad@ntnu.no, or Professor Frank Mauseth at telephone +47 73594234 or by email frank.mauseth@ntnu.no. If you have any questions about the recruitment process, please contact HR consultant Sven Robert Storø by e-mail sven.r.storo@ntnu.no. 

If you think this looks interesting and in line with your qualifications, please submit your application electronically via jobbnorge.no with your CV, diplomas and certificates attached. Applications submitted elsewhere will not be considered. Upon request, you must be able to obtain certified copies of your documentation.  

Application deadline: 13.01.25