CN-122014364-A - Geothermal power station steam pressure PCV valve bank control method and system

CN122014364ACN 122014364 ACN122014364 ACN 122014364ACN-122014364-A

Abstract

The application belongs to the technical field of control of a steam pressure valve bank of a geothermal power station, and relates to a control method and a control system of a steam pressure PCV valve bank of the geothermal power station, wherein the method comprises the steps of obtaining the rear pressure of a steam header and the rear pressure of a demister, and performing median selection on the rear pressures of three demisters; the method comprises the steps of switching control objects between starting and normal operation according to a steam turbine operation signal and a reset signal, performing proportional integral differential operation on deviation of the control objects and a pressure set value to obtain a total opening instruction, generating opening instructions of a fine adjustment control valve and an exhaust valve set according to a split-range mapping and valve opening sequence, automatically reordering the valve opening sequence and the split-range relation under an automatic valve cutting state, adopting a strategy of quick opening and holding when the steam turbine trips, a generator is in load shedding or island operation, and switching back to proportional integral differential operation output after the holding is finished. The technical scheme of the application is suitable for the steam discharge station of the geothermal power station, and can realize the coordination of stable regulation of steam pressure and transient discharge under multiple working conditions.

Inventors

LIU QINGPO
WANG JI
LIU ZONGGEN
SU MINTUAN
YANG CHAO
TIAN ZHIGANG
AN ZHENYU

Assignees

青岛华丰伟业电力科技工程有限公司

Dates

Publication Date: 20260512
Application Date: 20260126

Claims (10)

1. The geothermal power station steam pressure PCV valve group control method is characterized by comprising the following steps of: acquiring a steam header post-pressure measurement value and a demister post-pressure measurement value, wherein the demister post-pressure measurement value is obtained by selecting a median value from three pressure measuring points; Switching between a normal operation mode and a starting mode according to the operation signal and the reset signal of the steam turbine, selecting a measured value of pressure after the demister as a control object in the normal operation mode, and selecting a measured value of pressure after the steam header as a control object in the starting mode; Proportional integral differential operation is carried out on the deviation between the control object and the pressure set value to obtain a total opening instruction; Generating a fine adjustment control valve opening instruction and an exhaust valve opening instruction according to the total opening instruction and a preset branch mapping rule, putting into adjustment according to a preset valve opening sequence, and executing automatic re-sequencing on the valve opening sequence and the branch mapping rule when any valve is in an automatic cutting state; when the tripping of the steam turbine, the load shedding of the generator or the island operation is detected, the total opening instruction is replaced by a quick opening instruction, the exhaust valve group is quickly opened according to the reordered valve opening sequence and kept for a preset time period, and the replacement is released and switched back to the proportional-integral-differential operation output after the maintenance is finished.
2. The geothermal power plant steam pressure PCV valve group control method according to claim 1, wherein the step of obtaining the demister back pressure measurement value comprises the steps of carrying out consistency discrimination on the pressure values of three pressure measurement points, eliminating the pressure measurement points with deviation exceeding a preset deviation threshold when the consistency discrimination is not satisfied, and carrying out median selection on the residual pressure measurement points after elimination to obtain the demister back pressure measurement value.
3. The geothermal power plant steam pressure PCV valve control of claim 1, wherein the step of switching between the normal operation mode and the start-up mode based on the turbine operation signal and the reset signal comprises latching the start-up mode and disabling the switching to the normal operation mode when the turbine operation signal is inactive and releasing the latch and enabling the switching to the normal operation mode when the reset signal is active.
4. The geothermal power plant steam pressure PCV valve group control method according to claim 1, wherein when a proportional-integral-derivative operation is performed to obtain a total opening command, an integral term of the proportional-integral-derivative operation is limited, and accumulation of the integral term is stopped when the total opening command reaches a preset opening upper limit or a preset opening lower limit.
5. The geothermal power plant vapor pressure PCV valve control method of claim 1, wherein the step of performing automatic reordering of the valve sequence comprises obtaining an in-service signal for each of the trim control valve and the exhaust valve sequence, updating the valve sequence based on the in-service signal, rejecting the valve in the cut-off automatic state from the valve sequence when either valve is in the cut-off automatic state, and triggering automatic reordering.
6. The geothermal power plant vapor pressure PCV valve control method of claim 5, wherein the step of performing automatic re-sequencing of the split map rules comprises obtaining effective flow capacity parameters corresponding to each of the trim control valve and the exhaust valve set, re-assigning the split intervals of the preset split map rules according to the effective flow capacity parameters, and satisfying the exhaust valve set opening command with respect to the total opening command monotonically continuous.
7. The geothermal power plant vapor pressure PCV valve assembly control method of claim 6, wherein the steps of generating a trim control valve opening command and an exhaust valve assembly opening command comprise the trim control valve receiving a continuous map throughout a range of a total opening command, the trim control valve continuously receiving an incremental allocation of the total opening command while any valve of the exhaust valve assembly is engaged in the adjustment.
8. The geothermal power plant steam pressure PCV valve control method according to claim 1, wherein the step of replacing the total opening command with the quick opening command and maintaining the preset time period includes determining the preset time period according to a preset load interval to which the generator load belongs, determining whether the control object satisfies a preset restoration condition during the maintaining period, and ending the maintaining in advance when the control object satisfies the preset restoration condition.
9. The geothermal power plant vapor pressure PCV valve control of claim 1, wherein the step of releasing the substitution and switching back to the pid operation output comprises applying a slope limit to the rapid opening command, restoring the total opening command after the slope limit transition is completed and generating the exhaust valve opening command based on the pid operation output.
10. A geothermal power plant vapor pressure PCV valve stack control system, comprising: the pressure acquisition unit is used for acquiring a steam header rear pressure measurement value and a demister rear pressure measurement value, and the demister rear pressure measurement value is obtained by median selection of three pressure measuring points; the mode switching unit is used for switching between a normal operation mode and a starting mode according to the operation signal and the reset signal of the steam turbine, selecting a measured value of the pressure after the demister as a control object in the normal operation mode, and selecting a measured value of the pressure after the steam header as a control object in the starting mode; the PID calculation unit is used for performing proportional-integral-derivative operation on the deviation between the control object and the pressure set value to obtain a total opening instruction; the branch distribution unit is used for generating a fine adjustment control valve opening instruction and an exhaust valve opening instruction according to the total opening instruction and a preset branch mapping rule, and throwing and adjusting according to a preset valve opening sequence; An automatic re-ordering unit for performing automatic re-ordering of the valve opening sequence and the part-pass mapping rule when any valve is in the cut-off automatic state; the transient control unit is used for replacing the total opening instruction with a quick opening instruction when the tripping of the steam turbine, the load shedding of the generator or the island operation is detected, enabling the exhaust valve group to be quickly opened according to the reordered valve opening sequence and keeping the preset time length, and releasing the replacement and switching back to the proportional-integral-derivative operation output after the keeping is finished.

Description

Geothermal power station steam pressure PCV valve bank control method and system Technical Field The invention belongs to the technical field of geothermal power station steam pressure valve bank control, and particularly relates to a geothermal power station steam pressure PCV valve bank control method and system. Background In the prior art, steam pressure regulation of a geothermal power station steam discharge station is generally performed by means of pressure measurement point acquisition, controller operation and PCV valve bank, and overpressure protection and noise discharge management requirements of a steam turbine in the starting and stopping and running processes are met by performing closed-loop regulation on main steam or discharge pipeline pressure. However, the existing PCV valve group control method has some obvious disadvantages in the aspect of switching the pressure control objects under multiple working conditions and matching the cooperative adjustment of the valve groups. In practical application, the geothermal system has fast change of steam flow direction and pressure characteristic and change of control object and valve group burden along with working condition change during the period from production well operation and startup to grid-connected loading, the existing control strategy adopts a fixed control object selection and fixed valve distribution relation, the adjustment force distribution is easy to be unbalanced after overhaul and cutting or valve characteristic drift, the pressure fluctuation inhibition level is weak, the valve action frequency is high, and the consistency of pressure release action and follow-up adjustment connection is low under the emergency of tripping, load shedding and the like, and secondary fluctuation is easy to be introduced. Therefore, the problems that the overall regulation stability of the steam pressure of the geothermal power station is weak, the protection pressure relief and the subsequent pressure stabilizing control are low and the like in the prior art are often caused under the conditions of multi-station switching and sudden disturbance. This is a disadvantage of the prior art. In view of the above, it is desirable to provide a method and a system for controlling a steam pressure PCV valve set of a geothermal power plant to solve the above-mentioned drawbacks of the prior art. Disclosure of Invention The invention aims to provide a control method and a system for a geothermal power station steam pressure PCV valve group, which are designed to solve the technical problems, aiming at the defects that the overall regulation stability of the geothermal power station steam pressure is weak, the cooperative level of protection pressure relief and subsequent pressure stabilizing control is low under the conditions of multi-working condition switching and sudden disturbance in the prior art. In order to achieve the above purpose, the present invention provides the following technical solutions: In a first aspect, the present application provides a geothermal power plant steam pressure PCV valve group control method, including: acquiring a steam header post-pressure measurement value and a demister post-pressure measurement value, wherein the demister post-pressure measurement value is obtained by selecting a median value from three pressure measuring points; Switching between a normal operation mode and a starting mode according to the operation signal and the reset signal of the steam turbine, selecting a measured value of pressure after the demister as a control object in the normal operation mode, and selecting a measured value of pressure after the steam header as a control object in the starting mode; Proportional integral differential operation is carried out on the deviation between the control object and the pressure set value to obtain a total opening instruction; Generating a fine adjustment control valve opening instruction and an exhaust valve opening instruction according to the total opening instruction and a preset branch mapping rule, putting into adjustment according to a preset valve opening sequence, and executing automatic re-sequencing on the valve opening sequence and the branch mapping rule when any valve is in an automatic cutting state; when the tripping of the steam turbine, the load shedding of the generator or the island operation is detected, the total opening instruction is replaced by a quick opening instruction, the exhaust valve group is quickly opened according to the reordered valve opening sequence and kept for a preset time period, and the replacement is released and switched back to the proportional-integral-differential operation output after the maintenance is finished. By adopting the technical scheme, the control input is led in cooperation with the two-position pressure quantity through the median selection of three pressure measuring points, so that the robustness of the measuring point drift and t