Cooling Control Method of Steam Turbine Shutdown

Abstract

A steam turbine shutdown cooling control method comprises the steps of: setting all cold sources in a shutdown state after normal outage outage of a steam turbine generating set; and executing the following steps: s1, setting a drain valve related to a moisture separator reheater and a drain valve connected with a high pressure cylinder in an open state; s2, controlling steam turbine workshop ventilation system to be in normal operation, and setting a large power axial-flow blower fan around the high pressure cylinder. The method prevents cold source temperature drop; the step s1 can reinforce inner air-flow nature flow with a connected system; the step2 can realize cylinder external insulation and environment convection heat exchange, thus accelerating cooling speed, shortening a jiggering cooling time after the steam turbine outage, and preventing a problems that the life of related equipment can be affected in a cold source cooling mode; furthermore, a monitoring step can be simultaneously carried out with the execution of an intervention step, thus realizing equipment parameter quantification monitor, properly accelerating uniform and controllable cooling of the steam turbine cylinder and high pressure rotor movable-fixed parts.

Description

technical field [0001] The invention relates to the field of nuclear power maintenance, in particular to a cooling control method for steam turbine shutdown. Background technique [0002] During minor repairs and overhauls of nuclear power plants, the shutdown cooling of steam turbines occupies a certain period of time. In view of the conservative decision-making of equipment safety and the factors such as not violating the restrictions in the technical documents of the manufacturer, generally no intervention is made in the shutdown cooling of conventional island steam turbines, and a completely natural cooling method is adopted. This cooling method has the problem of long cranking time of the steam turbine after shutdown, so it is necessary to intervene and improve the shutdown cooling to compress the effective maintenance period. In conventional nuclear power plant maintenance, commonly used steam turbine shutdown cooling intervention techniques are: [0003] 1) The steam...

AI Technical Summary

Problems solved by technology

[0008] Artificially introducing an external cold source, the dynamic and static parts of the steam turbine cylinder, high-pressure rotor, etc. are not uniformly cooled, and potential equipment hazards such as cylinder deformation and cracks on the inner wall of the cylinder are prone to occur, which will affect the life of the unit, and may cause major equipment damage such as steam turbine shaft bending in severe cases Accidents; and increasing the temperature limit of steam turbine unit cranking shutdown may lead to accidents such as overheating of steam turbine bearings, partial melting of tungsten gold, and even burning of bearing bushes

In addition, the manual intervention of cooling is empirical and subjective, and it is not easy to carry out standardized control. It is prone to rapid advances due to lack of personnel experience or pressure on construction schedules, severe deformation of cylinders, permanent bending of high-pressure rotors and other major equipment damage accidents.

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