Netherlands: 2 PhD Positions-Experimentally studying the mechanisms of surface flashover
| In high voltage technology, vital parts are usually covered with insulating material. However, detrimental breakdown still can occur in the gas region outside the solid insulation. |
In many cases, a discharge creeps along an insulator surface where it can propagate over longer distances than in the bulk of the gas. The underlying physics is poorly understood, and control and prevention is usually based on empirical design rules or on oversimplified engineering models, or even on trial and error.
But experimental and theoretical methods are now ripe to analyze these creeping sparks as a fundamental physics problem and to understand how they depend on gas and insulator properties. How and where does the discharge start in the absence of electrodes? How do discharge channels grow over surfaces or through the gas? When do they heat up and create an electric short-circuit?
Discharges creeping over insulator surfaces frequently dominate the break-down, because the surface can modify the local electric field, it can store surface charges, and it can release electrons. We will quantify these microscopic effects with new experimental diagnostics and we will characterize the macroscopic discharge evolution. Finally, the project will provide design tools predicting how surface break-down depends on materials, geometries and applied voltage.
This project is sponsored by STW with the project title Creeping Sparks - Understanding the mechanisms of surface flashover: towards an efficient and reliable electric power grid. The work will be done in cooperation with the Centrum Wiskunde & Informatica in Amsterdam and ABB Corporate Research in Baden-Dättwil, Switzerland.
Project focus:
Both PhD candidates will: Study the start of the discharge with a nanosecond fast ICCD-camera and accurate current measurements. Characterize the various stages of discharge evolution with detailed optical, electrical and spectroscopic measurements.
PhD Candidate position 1, located at the EPG group of the Applied Physics Department
The PhD student will measure the evolution of the electric field on the insulator surface with imaging ellipsometry, with a resolution of ~10 ns and 1 mm. Charges left on a surface change the electric field on the insulator surface, and we will measure this field in model experiments with a flat surface and attached electrodes. Below a thin layer of the surface material under study, we will mount a crystal that changes its birefringence when exposed to an electrical field. This birefringence is then measured by imaging ellipsometry on the back side.
The research will be carried out at the Elementary Processes in Gas Discharges (EPG) group at the Applied Physics Department of the Eindhoven University of Technology (The Netherlands).
PhD Candidate position 2, located at the EES group of the Electrical Engineering Department
The PhD student will measure electron emission from an insulator surface, under UV-illumination and/or the application of an electric field. A dielectric insulator is positioned on a metal electrode, and irradiated by UV photons. A metal mesh at a certain (high) voltage level is used to apply (high) electric fields and is needed to close the electric circuit. We aim for a system where both the UV intensity as well as the wavelength can be varied over a large range to simulate the discharge. The emitted secondary electrons will be measured by a high-resolution electrometer.
The research will be carried out at the Electrical Energy Systems (EES) group at the Electrical Engineering Department of the Eindhoven University of Technology (The Netherlands).
Requirements:
The successful candidate has a Master degree and an excellent academic record in physics and/or electrical engineering. He/she must have a strong attitude towards experimental physics or electrical engineering with a focus on plasma physics and/or high voltage technology.
Employment Conditions:
The appointment is for four years. You will be an employee of the university with a competitive salary as well as excellent secondary benefits (holiday allowance, etc.). The research in this project must be concluded with the attainment of a PhD degree. A salary is offered starting at Euro 2042. - per month (gross) in the first year and increasing up to Euro 2612. - per month (gross) in the last year. Moreover 8% bonus share (holiday supplement) is provided annually, as well as a 8.3% end of year allowance. Assistance for finding accommodation can be given. TU/e offers you also the opportunity for personal development by developing your social and communication skills. We do this by offering every PhD student a series of courses that are part of the PROOF program as an excellent addition to your scientific education.
More information on employment conditions can be found here: http://w3.tue.nl/en/services/dpo/.
Information:
For further information on these vacancies you can contact:
Dr.ir. S. Nijdam, Department of Applied Physics, +31 40 274 342 or s.nijdam@tue.nl
Dr.ing. A.J.M. Pemen, Department of Electrical Engineering +31 40 247 4492 or A.J.M.Pemen@tue.nl
Application:
If you are interested in this position, please upload (max 300 kB, no large attachments) a detailed curriculum vitae, an application letter motivating why the position and the proposed research is of interest to you and the names of two references
Application Deadline: 15 January 2012
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