Quantitative Evaluation of Ozone Decomposition Rate Coefficient via Collisions with Water Vapor Molecules

Partial discharges (PDs) frequently occur in large-scale industrial motors during prolonged operation, leading to the degradation of insulation materials. Such degradation is typically assessed through offline disassembly inspections, which are time-consuming and costly. Therefore, a growing demand is for developing real-time diagnostic techniques. We propose a novel diagnostic method using ozone produced by PDs as an indicator. Although the correlation between ozone concentration and insulation degradation has been qualitatively recognized, quantitative evaluation remains challenging. This is due to the influence of environmental parameters, including temperature and humidity, on the ozone generation and decomposition. To overcome this limitation, we introduce the ozone generation rate. Assuming a steady state where the ozone generation rate equals the decomposition rate, the generation rate can be derived from the experimentally determined decomposition time constant. We investigated the relationship between water vapor concentration and ozone decomposition rate and quantified the decomposition rate coefficient. Under defined temperature and humidity conditions, the rate coefficient was estimated to be approximately 2.75 × 10⁻²³ s⁻¹cm³/particle. These findings provide a physical basis for using ozone kinetics, enabling the estimation of discharge activity. The proposed method offers a promising approach for continuous degradation monitoring in high-voltage equipment.