Study on the aging characteristics of reactor encapsulating insulation based on time-domain dielectric response

Dry-type air core reactor is one of the most important pieces of equipment in the power system. Due to its long-term exposure to high temperature and high field, the electrical and mechanical properties of its encapsulated insulation material are significantly reduced, leading to cracking, especially in cold regions with large temperature differences, which can exacerbate the phenomenon of encapsulated insulation cracking and cause equipment failure. This article prepared a scaled reactor model and subjected it to 0 h, 72 h, 168 h, and 288 h thermal aging. Samples with different aging times were subjected to 0, 3, 6, and 9 cold and hot shocks, and time-domain dielectric response testing (PDC) was conducted. The experimental results show that the polarization current and depolarization current of the encapsulated insulation with different cold and hot shock cycles gradually increase with the increase of shock number, and the amount of polarization charge increases with the increase of cold and hot shock. The research content of this article provides basic data for the maintenance and insulation state detection technology improvement of dry-type reactors in cold regions.