Abstract:
The temperature-pressure characteristics of the insulation interface of GIS terminal are studied in view of the working conditions of low-temperature environment. A 220 kV GIS terminal test platform is built, and the thermal-mechanical stress characteristics of the insulating interface between the cable body and the stress cone under different low temperature environments and different loading rate conditions are studied, and the simulation model is revised accordingly, and finally the influence of GIS terminal tail pipe temperature on the thermal-mechanical stress of the insulating interface is explored. The results show that the temperature change at the root of the cable body-stress cone interface is the fastest, and the interfacial pressure drop rate is the largest. When the ambient temperature drops from room temperature to −25 ℃, the pressure at the root of the cable body-stress cone interface drops to 7.8% of the initial state. Compared with 20% load operating conditions, the temperature of the terminal insulated interface is higher under 100% load conditions, but the interface pressure drops faster as the ambient temperature drops. The experimental results of the temperature distribution of the full-size GIS terminal are highly consistent with the simulation calculation results, and the deviation between the two is within ±5 ℃. In addition, the temperature of the GIS terminal tail pipe is positively correlated with the interface temperature and pressure. When the tail pipe temperature is ≥30 ℃, the interface pressure can be restored to more than 40% of the initial state. The research results verify the effectiveness of the simulation model of the insulation interface temperature field of GIS terminals in low-temperature environments, and an interface pressure control method is proposed based on terminal tail temperature control, which can provide an important reference for GIS cable terminal insulation design and operation and maintenance strategy in low temperature environment.