• High-voltage (extra-high-voltage) insulation performance under surge and impulse conditions is shaped by gas-insulation configurations, air density, and scaling from model tests to towers, indicating thresholds and reliability limits across EHV systems [8], [9], [12], [13], [16], [17].

• Thermally stimulated conduction and trap-mediated currents unify diverse insulator studies, linking luminescence, TSC, discrete trapping levels, and nonequilibrium statistics to explain temperature- and field-dependent dielectric behavior [4], [6], [10], [11], [18].

• Surface-charge measurements and potential-probe theory provide core diagnostics of insulating surfaces, revealing charge evolution, static electrification, and surface-state effects that govern long-term performance [14], [20].

• Dielectric breakdown theory and material response in solids underpin mechanistic models of failure and dielectric increment, integrating solid-state behavior with polyelectrolyte dielectric properties [3], [10], [18].

• Thermal transport across packed insulation beds and interfaces, including cryogenic and metal-insulator boundaries, informs effective conductivity and energy-utility design decisions [5], [7], [19].