Cooling of synchronous generators is divided into two types: external cooling and internal cooling.
1. External cooling: including air cooling and hydrogen cooling.
Air Cooling: The cooling medium is air, i.e. air is used to carry away the heat generated due to losses in the generator. This method has a simple structure, but the cooling efficiency is not high. The maximum installed capacity can reach around 100 MW.
Hydrogen cooling: The cooling medium is hydrogen, that is, hydrogen is used to remove heat. High cooling capacity compared to air. The ventilation loss is low, but the structure is complex and requires hydrogen storage equipment. The maximum installed capacity can reach around 200 MW.
2. Refinternal cooling: including internal water cooling of stator, internal hydrogen cooling of rotor, etc.
Internal cooling (direct cooling method): the cooling medium is water, oil or hydrogen, that is, hydrogen, Water or oil passes through the inside of the wire to carry heat away directly from it. the two aforementioned surface cooling methods. The high cooling capacity can reduce the size of the generator, save materials and facilitate the manufacturing of large capacity generators. However, the generator structure is complex, copper loss is large, iron loss and. the mechanical losses are low and the total loss is similar.