The gearbox of wind power generation belongs to closed gear driving type, and the main failure modes are gluing and pitting. Therefore, when choosing lubricating oil, the key is to ensure sufficient oil film thickness and boundary film strength. The radiator in the lubricating oil system is usually cooled by air and controlled by the temperature sensor in the system. If necessary, the cooling circuit opens automatically through the electric control bypass valve so that the oil flows out of the radiator before entering the transmission.