Rotor local thermal stress unevenness monitoring method of steam turbine in low load working condition

Abstract

The invention relates to a rotor local thermal stress unevenness monitoring method of a steam turbine in a low load working condition, belongs to the thermotechnical field of a power plant, and solvesthe problem that conventional steam turbine rotor thermal stress monitoring means are difficult to reflect the unevenness of rotor local thermal stress in the low load working condition, in particular the problem of unevenness of the circumferential thermal stress of the rotor in the working condition. The method comprises the following steps: S1, circumferentially and uniformly arranging m steamtemperature sensors and n steam pressure sensors on a cylinder of a regulating stage of a steam turbine unit; S2, defining representative circumferential temperature mean value formula and pressure mean value formula (refer to the Specification); and S3, acquiring sigmai and taui by a steam turbine unit control system according to Ti, Tj and the temperature mean value formula and the pressure mean value formula (refer to the Specification), and displaying the acquired sigmai and taui by the steam turbine unit control system through a display so as to monitor the local thermal stress of the rotor of the unit.

Description

technical field

[0001] The invention relates to a method for monitoring thermal stress of a steam turbine rotor in a low-load working condition, and belongs to the technical field of thermal engineering of a power plant. Background technique

[0002] With the continuous improvement of power grid's requirements for thermal power unit peak regulation performance, thermal power unit peak regulation performance is developing in the direction of deep peak regulation (deep regulation), rapid peak regulation (fast regulation) and precise regulation (fine regulation). Deep adjustment means that the unit will operate at low load. In order to ensure the economy of the unit, the operation mode under low load is more of a sequential valve adjustment method. In the sequence valve mode, one or two valves are partially open, and the other valves are fully open (or fully closed). The uneven steam intake mode under this low-load sequence valve adjustment mode causes the rotor to withstand mo...

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