Views: 4 Author: Site Editor Publish Time: 2025-06-11 Origin: Site
Cooling method
Air cooling: use air as cooling medium to cool the stator winding, rotor winding and stator core surface of hydro generator. It can be categorized into open ventilation, pipeline ventilation and closed circulation ventilation, which has the advantages of simple structure and convenient maintenance, but the cooling efficiency is low.
Water cooling: also known as water cooling, in the rotor windings, stator windings through the cooling water for direct cooling. According to the part of the cooling is divided into single water cooling method and double water cooling method. Double water cooling method cooling effect is better, you can reduce the generator size, reduce the cost, and accordingly increase the capacity, but the sealing structure is complex, the water quality requirements are higher, operation and maintenance workload is larger.
Evaporative cooling: the low boiling point of the medium (such as Freon) into the winding, the use of rapid evaporation of the medium to absorb heat for cooling. This way of cooling efficiency, cooling medium insulation is good, no electrolysis, no combustion, no corrosion, but the sealing structure of the higher requirements.
Performance requirements
Cooling capacity: air cooler cooling capacity design margin should not be less than 115%, and should ensure that the power generating motor in the rated operating conditions, any one cooler out of operation, when the inlet cooling water temperature ≤ 30 ℃, the cooler outlet air temperature does not exceed 40 ℃, the power generating motor parts of the temperature rise does not exceed the permissible temperature rise limit value.
Material selection: air cooler should be made of high thermal conductivity copper-nickel alloy seamless tube and other corrosion-resistant materials, the upper and lower tank cover should be made removable, and does not affect the pipeline connection, the tube plate plate should be corrosion-resistant stainless steel. The sealing material of the end cover should not use ordinary nitrile rubber with short aging life, and the service life of the material should be not less than 10 years.
Pressure design: cooler according to the unit cooling water pressure according to the maximum pressure of 1.6MPa or 2.5MPa design, test water pressure is 1.5 times the maximum pressure for 30min, and then the pressure will be reduced to the design of the maximum pressure and then maintained for 30min, the cooler shall not have any leakage or damage. The water pressure drop between the inlet and outlet pressure gauge of the cooler shall not exceed 0.05MPa.
Positioning: The position of the cooler shall be convenient for disassembling and lifting out during maintenance, and it shall be avoided as far as possible to be arranged in the main lead line and the neutral lead line directly underneath. If the arrangement in the main lead line and neutral lead line is directly below, there should be measures to disassemble and lifting out.
