Abstract: Partial discharges (PD) in floating bubbles and in microspheres made from thin glass walls in transformer oil were studied experimentally and theoretically. In a test cell, the PD occurrence was a very rare event. Sometimes PD in bubbles occurred after exposure for more than 10 hours at a voltage that corresponds to a value three times the voltage in accordance with Paschen's law. In the case of a glass microsphere, PD takes place at a voltage according to Paschen's law after several hours but afterwards PD occurs more frequently. The reason for this is in the starting electrons which initiate the first avalanche. It is shown with 100 keV X-rays that PD occurs in all bubbles and its inception voltage corresponds to Paschen's law. Theoretical analysis shows that, at the conditions of PD occurrence in helium bubbles, breakdown fits the streamer mechanism. Registrations of electrical and optical signals of PD were performed to estimate apparent and true charges and the number of radiated photons. As a result of the evaluation, the number of electrons is approximately equal to the number of photons.

Cite: Korobeynikov S.M. , Ridel A.V. , Karpov D.I. , Meredova M.B. , Ovsyannikov A.G.
Mechanism of partial discharges in free helium bubbles in transformer oil
IEEE Transactions on Dielectrics and Electrical Insulation. 2019. Т.26. №5. 8858131 :1-7. DOI: 10.1109/TDEI.2019.008199 WOS Scopus РИНЦ OpenAlex

Identifiers:

Web of science:	WOS:000492443800030
Scopus:	2-s2.0-85077315628
Elibrary:	43230139
OpenAlex:	W2978758780

Citing:

DB	Citing
OpenAlex	16
Elibrary	25
Scopus	21
Web of science	15

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