Steam turbine single valve and sequence valve switching steam inlet method

Abstract

The invention discloses a steam turbine single valve and sequence valve switching steam inlet method. When the unit is started or operates in a peak regulation mode, single-valve control also needs to be adopted. However, when a single valve operates, a high-pressure regulating valve participates in opening degree regulation, and the opening degree of the high-pressure regulating valve is generally not large, so that the throttling loss is relatively large when the steam passes through the regulating valve. The method comprises the following steps that the unit load is reduced to 150-170MW, and a first-stage industrial steam extraction medium and a second-stage industrial steam extraction medium are adopted; unit coordination is relieved, automatic control and power feedback are put into use, and main steam pressure and load are kept stable; recording the opening degree of the # 1-4 high-pressure control valves of the unit and the parameters of each bearing bush; starting unit sequence valve control; observing whether the change condition of the 1-4 high-voltage control valves is normal or not; the parameter change condition of each bearing bush in the switching process is observed and recorded; after the unit operates stably and all parameters are normal, coordination control is put into use, loads are gradually increased, and all the parameters are observed and recorded. The invention is used for steam turbine single valve and sequence valve switching steam admission.

Description

TECHNICAL FIELD

[0001] The present application relates to a kind of steam turbine single valve, sequence valve switching admission method. BACKGROUND

[0002] The unit generally adopts single valve operation mode during commissioning, so that the temperature difference between rotor and stator is small, and the temperature difference has little effect on variable load operation, which is beneficial to the initial running-in of the unit. In addition, single valve control is also required during unit startup process or peak shaving operation. However, in single valve operation, high pressure regulating valve is involved in opening degree regulation, and the opening degree of high pressure regulating valve is generally small, so there is a large throttling loss when steam passes through the regulating valve. SUMMARY

[0003] The purpose of the present application is to provide a kind of steam turbine single valve, sequence valve switching admission method, to solve the above-mentioned technical problems.

[0004] The above-mentioned purpose is realized by the following technical scheme: A kind of steam turbine single valve, sequence valve switching admission method, the method comprises the following steps: (1) reduce the unit load to 150-170MW, and insert the first and second stage industrial steam extraction; (2) release the unit coordination, input "automatic" control and power feedback, and keep the main steam pressure and load stable; (3) record the opening degree of high pressure regulating valve #1-4 and the bearing parameter of each shaft; (4) input the sequence valve control of the unit; (5) observe whether the change of 1-4 high pressure regulating valve is normal; (6) observe and record the change of bearing parameter during switching process; (7) after the unit runs stably and each parameter is normal, input the coordination control, gradually increase the load to 230-240MW, and observe and record each parameter; (8) after the test is completed, keep the unit running in sequence valve control mode, and re-arrange the operation mode by the value long, and adjust the electric heating load.

[0005] The steam turbine single valve, sequence valve switching admission method, the bearing parameter in step (3) includes vibration, admission, expansion, differential expansion and axial displacement.

[0006] The steam turbine single valve, sequence valve switching admission method, step (7) specifically includes: (71) after the unit runs stably and each parameter is normal, input the coordination control, gradually increase the load to 230-240MW, and observe and record each parameter; (72) input the first and second stage industrial steam extraction, and observe and record each parameter; (73) gradually load to 280-300MW, observe and record each parameter. Beneficial effects

[0007] 1. Under the control mode of the sequential valve of the application, only one high-pressure regulating valve is adjusted in opening degree, and the remaining valves are kept fully open or fully closed, thereby reducing throttling loss and improving the thermal efficiency of the unit.

[0008] 2. The application accurately calculates the control mode of different valves under different working conditions, as well as the opening degree of each valve corresponding to different steam flow under different working conditions, to realize valve opening degree adjustment; at the same time, the balance switching between single valve and sequential valve control is realized without disturbing the unit operation. DETAILED DESCRIPTION

[0009] A steam turbine single valve and sequential valve switching method, comprising the following steps: (1) Reduce the unit load to 150-170MW, and insert the first and second stage industrial extraction; (2) Remove the unit coordination, input "automatic" control and power feedback, and keep the main steam pressure and load stable; (3) Record the opening degree of the #1-4 high-pressure regulating valve and the bearing parameters; (4) Input the sequential valve control of the unit; (5) Observe whether the change of the 1-4 high-pressure regulating valve is normal; (6) Observe and record the change of the bearing parameters during the switching process; (7) After the unit runs stably and each parameter is normal, input the coordination control, gradually increase the load, and observe and record each parameter; (8) After the test work is completed, keep the unit running in the sequential valve control mode, and uniformly re-arrange the operation mode by the shift supervisor and adjust the electric heating load.

[0010] The steam turbine single valve and sequential valve switching method, the bearing parameters in step (3) include vibration, steam admission, expansion, differential expansion and axial displacement.

[0011] The steam turbine single valve and sequential valve switching method, step (7) specifically comprises: (71) After the unit runs stably and each parameter is normal, input the coordination control, gradually increase the load to 230-240MW, and observe and record each parameter; (72) Input the first and second stage industrial extraction, and observe and record each parameter; (73) Gradually increase the load to 280-300MW, and observe and record each parameter.

Claims

1. A method of switching steam admission in a steam turbine with single valve, sequential valve, characterized in that: The method comprises the following steps: (1) reduce the unit load to 150-170 MW, and arrange the first and second industrial steam extraction; (2) remove the unit coordination, input the "automatic" control and power feedback, and keep the main steam pressure and load stable; (3) record the opening degrees of the high-pressure regulating valves 1-4 and the bearing parameters; (4) input the unit sequence valve control; (5) observe whether the changes of the high-pressure regulating valves 1-4 are normal; (6) observe and record the changes of the bearing parameters during the switching process; (7) after the unit runs stably and the parameters are normal, input the coordination control, gradually increase the load, and observe and record the parameters; (8) after the test work is completed, keep the unit running in the sequence valve control mode, and uniformly re-arrange the operation mode by the shift supervisor and adjust the electric heating load.

2. A method of switching steam admission in a steam turbine with single valve, sequential valve according to claim 1, characterized in that: The bearing parameters in the step (3) comprise vibration, steam admission, expansion, differential expansion and axial displacement.

3. A method of switching steam admission in a steam turbine with single valve, sequential valve according to claim 2, characterized in that: The step (7) specifically comprises: (71) after the unit runs stably and the parameters are normal, input the coordination control, gradually increase the load to 230-240 MW, and observe and record the parameters; (72) input the first and second industrial steam extraction, and observe and record the parameters; (73) gradually increase the load to 280-300 MW, and observe and record the parameters.