Monitoring method for accumulative low-cycle fatigue life loss of thermal power generation unit components

Abstract

The invention relates to a thermal power generating unit component accumulated low-cycle fatigue life loss monitoring and control method. The thermal power generating unit component accumulated low-cycle fatigue life loss monitoring and control method is characterized in that the thermal power generating unit component accumulated low-cycle fatigue life loss monitoring and control method comprises the following steps that: online measurement point data of a thermal power generating unit is read; thermal stresses of important components are calculated; mechanical stresses of the important components are calculated; composite stresses of the important components are calculated; equivalent stresses of the important components are calculated; a maximum stress of three composite stresses is determined; a minimum stress of the three composite stresses is determined; real-number-field equivalent stresses of the important components are calculated; stress time intervals with the same sign are classified; and the peak stress of sigma ij >=0 time intervals is determined. The invention provides a thermal power generating unit important component accumulated low-cycle fatigue life loss online monitoring and control device and the thermal power generating unit important component accumulated low-cycle fatigue life loss online monitoring and control method. With the thermal power generating unit important component accumulated low-cycle fatigue life loss online monitoring and control device and method adopted, online calculation and control of accumulated low-cycle fatigue life losses of the important components of one or a plurality of thermal power generating units can be realized.

Description

technical field [0001] The invention relates to an on-line monitoring and control method for accumulative low-cycle fatigue life loss of important components of a thermal power generating set, and belongs to the technical field of thermal generating sets. Background technique [0002] The important components of the thermal power generating set with low cycle fatigue damage as the main failure mode are: high pressure rotor, medium pressure rotor, low pressure rotor, high pressure inner cylinder, medium pressure inner cylinder, high pressure outer cylinder, high pressure main steam valve casing, high pressure regulating valve Shell, generator rotor, generator retaining ring, drum, steam-water separator, high-temperature header, low-temperature header, main steam pipeline, reheat steam pipeline, etc. These important components are large in size and expensive to manufacture, and the consequences of fatigue damage are serious. During the start-up, shutdown and load changes of t...

AI Technical Summary

Problems solved by technology

These important components are large in size and expensive to manufacture, and the consequences of fatigue damage are serious

During the start-up, shutdown and load changes of the thermal power generating set, in the important parts of the thermal power generating set, relatively large thermal stress is generated due to the uneven temperature distribution along the radial direction, which causes the transient low cycle fatigue of the important parts of the thermal power generating set Increased life loss

During the service period of the thermal power generation unit, the long-term transient low-cycle fatigue life loss of important components will inevitably lead to an increase in the cumulative low-cycle fatigue life loss.

If the cumulative low-cycle fatigue life loss monitoring and control are improper, it will lead to low-cycle fatigue damage of important components of thermal power generating units, and there is an urgent need in engineering for an online monitoring and control device and method for cumulative low-cycle fatigue life loss of important components of thermal power generating units

[0003] The applicant has applied for patents "A Method and System for On-Line Monitoring of Low-Cycle Fatigue Life Loss of Steam Turbine Rotor" with application number 200710039898.3, "On-line Monitoring and Control Device and Method for Low-Cycle Fatigue Life Loss of Steam Turbine Components" with application number 200910050273.6, and "Rotor The device and method for on-line monitoring and control of low-cycle fatigue life loss of the retaining ring" application number is 200910201405.0 and the application number of "on-line monitoring and control device and method for transient low-cycle fatigue life loss of pressure-bearing parts outside the furnace" is 201010102187.8, and public literature reports The on-line management technology of fatigue life loss in China is to monitor and control the transient low-cycle fatigue life of the important parts of the generator set online, but there is no suitable monitoring and control for the monitoring and control of the cumulative low-cycle fatigue life loss of the important parts of the thermal power generating set. Apparatus and methods are available

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