Characteristics of Impulse-Driven Surface Flashover Across Polymers With Different Surface Conditions
Year: 2025
Type: article
Abstract: Power-centric research conducted in the past few decades has identified many influencing factors that affect and contribute to the development of high voltage surface flashover. Among them, the surface condition—morphology, roughness, and texture—is one such physical characteristic of gas-solid interfaces that is believed to be exploitable, relatively inexpensively, as a method to improve surface flashover strength. High voltage pulsed power systems and equipment face similar challenges, but there presently exists limited literature focused on impulse-driven flashover and the effects of surface roughness. In this work, the impulsive flashover strengths of five polymers relevant to pulsed power system design (PVC, Delrin, Ultem, Torlon, Perspex) are reported under two different (∼20 nanosecond and ∼100 microsecond risetime) impulse waveforms in atmospheric air. Samples of different surface conditions— “as received” and “machined”—were subjected to flashover tests, complemented with surface profilometry measurements to evaluate the effects of various roughness characteristics on the impulse-driven breakdown strengths and times-to-breakdown. The results obtained indicate a general enhancement of the impulsive flashover strength with increased roughness with a corresponding prolongation of the time-to-breakdown. Rougher “machined” surfaces were therefore found to outperform the smoother “as received” surfaces. A correlation analysis between the measured surface roughness parameters and the breakdown data suggests that the short-wavelength components of the surface profile contributes more towards the enhancement of the flashover strength compared to longer-wavelength “waviness” components. The consistency of this result with the theory of increased streamer path length and streamer inhibition is discussed, as are the potential consequences to insulator surface modification for flashover mitigation.
Authors: Timothy Wong, Igor Timoshkin, Scott MacGregor, Martin Given
Institution: University of Strathclyde
Language: English
Subfield: Materials Chemistry
Field: Materials Science
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $2,645
OpenAlex ID: W4410809689