Research on gas-liquid-solid insulation system in stator slot

In evaporative cooling turbogenerator, all structures are immersing in evaporative cooling medium. Evaporative cooling turbogenerator which is transformed from inner water-cooling turbogenerator has been developed successfully. However, it has not taken full advantage of evaporative cooling medium's superiority in insulation. Besides, the amount of cooling medium is relatively large. This paper redesigns and analyzes gas-liquid-solid insulation system in stator slot from the perspective of the evaporative cooling technology. Furthermore, this paper provides the most appropriate materials and optimum thickness for solid insulation layer and fixed insulation layer in new insulation system. At last, this paper discusses wrapping width and interval of fixed insulation layer by three-dimensional model of new-designed insulation system.

I. Introduction

The evaporative cooling technology is a new and efficient cooling technology, which uses high insulation, low boiling point organic fluid to transfer heat by phase transformation. The evaporative cooling technology has been successfully used in many electrical and electronic equipment^[1]: inner evaporative cooling hydrogenerator^[2], immersing evaporative cooling turbogenerator^[3], surface-mounted and spray-type evaporative cooling electronic equipment^{[4], [5]}, etc.^[6]