Poly(dicyclopentadiene) Coatings for the Mitigation of Surface Flashover in Gas Switch Housings

• Published in: 2022 IEEE Conference on Electrical Insulation and Dielectric Phenomena (CEIDP) pp. 483 - 486
• Main Authors: Burnette, M. L., Martinez, R., Faubel, J. L., Clem, P. G., Appelhans, L. N.
• Format: Conference Proceeding
• Language: English
• Published: IEEE 30-10-2022
• Subjects: Coatings; Dielectrics; Flashover; Oxidation; Polymers; Thermal factors; Threshold voltage
• ISSN: 2576-2397
• DOI: 10.1109/CEIDP55452.2022.9985317

Surface flashover is a significant issue impacting the reliability of high voltage, high current gas switches. The goal of this work is to determine if poly(dicyclopentadiene) (pDCPD) coatings can be used to mitigate surface flashover on insulators compared to crosslinked polystyrene (Rexolite), cast poly-methylmethacrylate) (PMMA), and extruded PMMA. The pDCPD coating is expected to have a higher flashover voltage threshold to an initial flashover due to the oxidation of the polymer, creating trap sites for any free electrons that would otherwise serve as primary electrons in a surface electron avalanche. This is tested by measuring the flashover threshold for different extents of oxidation caused by thermally treating the samples for different durations. For subsequent flashover events the pDCPD coating is also expected to have a higher flashover threshold due to its high oxygen/hydrogen to carbon ratio, which is expected to preferentially create gaseous products, such as CO2 after a flashover event, rather than conductive carbon deposits. The control and pDCPD-coated test coupons are repeatedly subjected to increasing voltage stresses until flashover occurs to determine both the initial and subsequent flashover thresholds.