Valve sequence optimization method and system for inhibiting steam flow excitation of large steam turbine generator unit

Abstract

The invention discloses a valve sequence optimization method and system for inhibiting steam flow excitation of a large steam turbine generator unit. The valve sequence optimization method comprises the following steps of: rising and falling normal load by utilizing an original sequence valve sequence of the unit, and obtaining shaft vibration signals of a first bearing bush and a second bearing bush and valve position signals of a third valve and a fourth valve; generating a trend chart of the shaft vibration of the first bearing bush and the second bearing bush and the valve positions of the third valve and the fourth valve; obtaining shaft vibration values of the first bearing bush and the second bearing bush in the opening process of the third valve and the fourth valve, and obtaining the influence degrees of valve positions of the third valve and the fourth valve on the shaft vibration of the first bearing bush and the second bearing bush; obtaining corresponding highest and lowest shaft vibration peak values, and determining valve positions of the third valve valve and the fourth valve corresponding to the highest and lowest shaft vibration peak values; determining a parallel combined opening mode of the third valve and the fourth valve; and determining the valve sequence opening mode most suitable for the unit. The combined opening mode of the sequence valve sequence is further optimized, the influence of steam flow force on a steam turbine rotor can be better reduced, and the steam flow excitation phenomenon is restrained.

Description

technical field [0001] The invention relates to the field of steam turbine valve control, in particular to a valve sequence optimization method and system for suppressing steam flow excitation of a large steam turbine generator set. Background technique [0002] With the continuous increase of the power generation capacity of large-scale units, the steam intake parameters have also been further increased, resulting in an increase in the exciting force on the high-pressure rotor. In severe cases, the high-voltage rotor is prone to instability, resulting in a large number of low-frequency vibrations, forming a fault phenomenon of steam excitation , because when each high-pressure regulating valve is opened, the steam flow force will generate a combined bending moment and a tangential force on the rotor. When the unit is in single-valve mode, the steam flow forces generated by the four valves cancel each other out. In this mode, the steam flow forces generated by the first valv...

AI Technical Summary

Problems solved by technology

[0002] With the continuous increase of the power generation capacity of large-scale units, the steam intake parameters have also been further increased, resulting in an increase in the exciting force on the high-pressure rotor. In severe cases, the high-voltage rotor is prone to instability, resulting in a large number of low-frequency vibrations, forming a fault phenomenon of steam excitation , because when each high-pressure regulating valve is opened, the steam flow force will generate a combined bending moment and a tangential force on the rotor. When the unit is in single-valve mode, the steam flow forces generated by the four valves cancel each other out. In this mode, the steam flow forces generated by the first valve and the second valve will cancel each other out, and when the third valve and the fourth valve are opened, the unbalanced steam flow will often be caused by the mismatch of the opening methods of the two high-pressure regulating valves. The flow force is generated, thereby destroying the original load of the bearing, changing the characteristics of the bearing pad, and causing the generation of steam flow excitation, especially in some capacity-enhancing units, which can easily induce large vibration of the high-pressure rotor or high temperature of the shoe, far exceeding the vibration of the steam turbine The alarm value has a huge impact on the unit's load capacity, safety, and equipment life

[0003] In view of steam flow excitation faults, related measures such as changing the valve sequence of the high-pressure regulating valve, improving the form of the sealing device, increasing the damping and stability of the bearing bush, and increasing the axial gap between the rotor and the diaphragm can be taken to suppress and treat it. Among them, changing the high-pressure The method of adjusting the valve sequence of the valve is the preferred treatment method because it can be implemented online. However, the current method is to change the opening sequence of the high-pressure regulating valve, which has certain limitations and cannot completely and effectively suppress the steam flow excitation online. Further optimization of the regulating valve

Images