Sand can be used, but if you use sand to put out a fire, you will be extinguished. However, sand is not easy to clean. The dry powder can also be used to put out fires. However, foam extinguishers cannot be used because they conduct electricity.
Generators below 150 MW typically use hydrogen and air cooling, and those above 150 MW use water cooling.
>Water cooling is a separate circuit. It does not come into direct contact with the windings or cores, but with water. is in the pipes while walking, the winding or core is outside to achieve cooling effect. The sand is so fine that it would be very difficult to pour and remove, and there is no guarantee that it can be completely removed. It will cause problems in work after extinguishing the fire.
SIf you want to use nitrogen for cooling, it is no different from air cooling, because our atmospheric nitrogen accounts for 78.12% of the total air, which cannot achieve the effect of cooling. The cost of using liquid nitrogen. is too high.