Impact of Extreme Environmental Temperature on the Electric-Thermal Field Distribution of ERIP Bushing for 750 kV High Voltage Reactors

In Xinjiang, China, Oil-immersed paper bushings used in reactors are highly susceptible to discharge breakdown faults due to drastic fluctuations in environmental and oil temperatures. To mitigate this problem, oil-free and explosion-proof epoxy resin-impregnated paper (ERIP) bushings are recommended as replacements. This study develops a multi-physics(electric-thermal-fluid) coupling model for 750 kV high voltage reactors ERIP bushings. The model aims to comprehensively assess their thermal and electrical performance under extreme ambient temperatures ranging from −40°C to 90°C and oil temperatures varying from −10°C to 90°C. The results demonstrate that the bushing temperature rises consistently with increases in ambient temperature. Additionally, the location of the hottest point on the conductive rod exhibits an upward shift as the ambient temperature climbs. Significantly, when a temperature difference exists between the oil and the external environment, this upward movement remains relatively constrained. Even when the external temperature increases from −40°C to 80°C, the hottest point shifts upward only 2457 mm. Conversely, in the absence of a temperature difference between the oil and external environment, a modest 10°C increase in ambient temperature (from 80°C to 90°C) triggers a substantial 11,356 mm upward displacement of the hottest point. Moreover, this study reveals that the electric field distribution within the bushings remains largely unaffected by environmental temperature changes.