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The design of high voltage (HV) devices, such as gas insulated switchgear and gas circuit breakers (CB), requires – among others – the accurate determination of their dielectric withstand. Aside from easily predictable quantities such as applied voltage, geometry, and nominal properties of materials (gaseous and solid), dielectric withstand is also heavily impacted by uncertain factors such as presence of particles, defects on surfaces, charges on dielectric materials/coatings, etc. These non-idealities can drastically reduce the expected performance of an HV device. The quantification of this performance reduction is done through measurements that attempt to reproduce working conditions as much as possible, including lab-based testing. During testing, the breaker must demonstrate several operations near the limits of its rated current and/or voltage. Performance is evaluated by the behavior of the breaker during the test as well as by subsequent disassembly and inspection. The aim of the internship will be twofold: on one hand, to provide active support for new project development (with a focus on SF6-alternative gases) by means of electric field simulations, test support, and test results analysis. On the other hand, to support maintaining the existing dielectric tools and the organized collection of available data, with the analysis and addition of recent tests and new data from literature.

Main Objectives

Physical understanding of gaseous breakdown and flashover processes. Analysis and evaluation of measurement data and breakdown database maintenance, with a focus on SF6-alternative gases. Support project teams for new project development (high voltage circuit breakers) by means of electric field simulations, maintenance of dielectric evaluation tools and testing support.

Tasks

• Become familiar with the internally-developed dielectric evaluation tools and contribute to their maintenance.

• Data post-processing, analysis and evaluation of internally-performed breakdown measurements and test results; update of breakdown database.

• Perform literature search on recent work regarding breakdowns/flashovers in technically relevant conditions, with a focus on gases alternative to SF6; data extraction (includes field simulations, e.g., Comsol)

• Collaborate in high voltage circuit breaker development project teams, mainly related to dielectric design, and for the following topics:

• Support the design process with breaker E-field simulations and optimizations.

• Support for testing, with data analysis and database maintenance.

• Support during and after test execution and with hands-on work during circuit breaker inspection and material analysis.

Requirements

• Student (preferably Master studies) in Physics, Mechanical, Electrical Engineering, or a related field

• Above average proficiency and interest in programming (e.g., Python and/or Matlab, Excel, utilization of Python libraries)

• Knowledge in High-Voltage Engineering is advantageous

• Fluency in written and spoken English

• Willingness to execute hands-on work in the laboratory

• Ability to work in a team, as well as willingness to handle responsibilities independently