Somya Anand defends his PhD on Jan. 13, 2022 at 10AM.
Place : SuperGrid Institute (Villeurbanne), visio only.
Jury :
Rapporteurs : Andrea CAVALLINI (Univ. Di Bologna), Olivier LESAINT (G2ELAB, Grenoble)
Examinateurs : Laurent PECASTAING (Univ. De Pau et des Pays de l’Adour), Marie-Laure LOCATELLI (Univ. Paul Sabatier), Mme Sonia AIT-AMAR (Univ. d’Artois), M. Charles JOUBERT (Univ. Claude Bernard)
Encadrement : Cyril BUTTAY (Ampère et INSA de Lyon), M. Eric VAGNON (Ampère et ECL), M. Martin GUILLET (SuperGrid Institute).
Abstract :
The inclusion of wide band gap devices (such as SiC MOSFETs) in the converters of future power network will introduce a new electrical constraint in the form of repetitive fast rising square voltage waveforms. These waveforms are expected to influence the discharge mechanism of insulators in high voltage (HV) apparatuses in a way different than AC sinusoidal waveforms. Therefore, this thesis aims to investigate the partial discharge (PD) mechanism under square voltage waveform for power electronic applications.
To achieve this goal, at first a test bench generating unipolar square voltage (USV) is developed with a HV switch. Due to the disturbances caused by electromagnetic interferences from high-speed switching of semiconductor devices, the PD detections are performed optically. For this a photomultiplier tube (PMT) is deployed which detects the photons emitted during discharge events. A cell with needle-barrier plane configuration filled with dielectric liquid is used as a device under test (DUT) and PD measurements are performed both under AC and unipolar square voltage (USV) waveforms. As compared to AC, a lower partial discharge inception voltage is found under USV. Moreover, a different PD mechanism is noticed under USV for tested specimens.
The major outcomes of this thesis are :
• Development of a USV test bench with dV/dt in a range of 10-100 kV/µs
• Demonstration of PMT as PD detector under USV waveform
• Developed test bench is capable of measuring PDs under varying USV parameters i.e. rise time, switching frequencies and duty cycle
• Test platform can be used for further PD studies in transparent media
Keywords :
Partial discharge, optical detection, unipolar square voltage, high dV/dt, dielectric liquid.
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