The main process flow of generator stator cooling water system is:
Stator cooling water tank---stator cooling water pump---exchanger cooling heat pump---mechanical filter---magnetic filter - --Generator stator winding---Stator cooling water tank
There are also two special subsystems, one nitrogen purge system and ion purification system: the nitrogen purge system is installed on the upper part of the stator cooling water tank, with nitrogen There are two pipelines for feeding and blowing; The ion purification system is a branch of the stator cooling water system. It mainly circulates part of the water after the mechanical filter through the ion purification system to remove ion impurities before returning. to the cooling water tankt of the stator.
Why is the generator stator cooling water higher than the temperature of the cold hydrogen? (Power plant electrical)
Turbine emergency shutdown conditions
Under the following circumstances, the unit should destroy the vacuum and trigger an emergency shutdown
The turbine suddenly vibrates strongly or exceeds the trigger value;
There is a clear sound of friction or metallic impact in the turbine or generator
When the turbine speed reaches 3300 rpm and the circuit breaker emergency does not work; make it work ;
Shaft seal or oil retaining ring is severely rubbed or sparks;
When water impact occurs in the turbine or the temperature main steam or reheated steam suddenly drops 50. ℃ or more within 10 minutes;
All bearing returns when the temperatureof oil reaches 75°C or a bearing cuts oil and smokes
When the temperature of any metal support of the support; or the metal of the thrust bearing rises to the emergency stop value;
The generator or exciter smokes and catches fire or the hydrogen system explodes;
When the axial displacement exceeds -1.65mm or +1.2mm and the device axial displacement protection does not work;
Lubricating oil drops to 0.06 MPa when AC/DC oil lubrication oil pump is still ineffective despite starting;
When the oil level in the main oil tank of the unit drops to the emergency stop value and oil replenishment is ineffective;
The system oil catches fire, which is serious when the safety of the unit is threatened;
When the temperature difference between the upper and lower cylinders of the high pressure outer cylinder dep50℃ or the temperature difference between the upper and lower cylinders of the high pressure inner cylinder exceeds 35℃;
The expansion difference of the unit reaches the emergency stop value.
The unit will not break the emergency vacuum shutdown under the following circumstances
When the main steam and reheat lines, water supply lines and other main lines rupture, threatening the safety of the unit. ;
When the condenser vacuum drops below -80.3 kPa or the circulating water is interrupted and cannot be restored immediately;
When the pump condensate fails, the water level in the condenser is too high and the backup pump cannot be put into operation;
The unit operates at idle speed or operates with power supply plant for more than 15 minutes after load shedding
Unit operates without steam for; more'one minute ;
The steam temperature at the exhaust port of the high pressure outer cylinder reaches 420°C, and the temperature of the low pressure cylinder reaches 420°C. 110 ℃;
MFT works;
Generator stops accidentally;
All energy used in the factory is lost;
When the anti-oil pressure drops to 7.83MPa and the protection refuses to work;
The main steam and reheat temperatures fluctuate between 547-557°C, continuously Operation exceeds 15 minutes or exceeds 557°C;
Main steam and reheat temperatures drop below 430°C;
When cooling water from generator stator is interrupted for 30 seconds and the protection does not operate;
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When the DEH system and the regulatory safety system fail to maintain normal operation;
When the quality of the soda exceeds the rregulation (chemical parameters provided).
This sentence applies to generators whose cooling method is water-hydrogen-hydrogen method, that is, water passes through the hollow conductor inside the stator winding and water carries away the heat generated during operation. of the generator to achieve the cooling effect. There are ventilation channels inside the stator core and rotor windings, which are cooled by hydrogen.
If the temperature of the internal cooling water of the generator stator winding is higher than the temperature of the hydrogen outside the winding, condensation will form on the outer surface of the stator winding, i.e. the insulation surface. of the stator winding will become very wet, which will damage the insulation of the stator winding. As a result, the stator winding will be partially discharged and nIt will no longer be able to function.