Method and system for controlling reheat steam of thermal power plant

Abstract

The invention relates to a reheat steam control method and system of a thermal power plant, and belongs to the technical field of thermal power generation, and the system comprises a reheat steam control module, a reheat steam temperature feedforward module and a reheat steam temperature control module; according to the method, a unit load instruction is received, the feed-forward module dynamically corrects air volume and fuel supply data, and the control module regulates and controls the opening degree of a flue baffle based on an inlet temperature mean value and regulates and controls desuperheating water spraying parameters according to an outlet temperature deviation matching mapping table. Closed-loop optimization is formed through cooperation of feedforward correction and feedback control, and a baffle opening decision is fed back to a fuel / air volume adjustment and water spraying data updating historical library. Steam temperature oscillation is effectively restrained, desuperheating water consumption is reduced, unit heat efficiency is improved, and a temperature sudden change emergency protection mechanism is achieved. The problem of oscillation caused by overshoot of traditional PID control is solved.

Description

Technical Field

[0001] The present application relates to the field of thermal power generation technology, and more specifically, to a reheat steam control method and system for a thermal power plant. Background Art

[0002] Steam reheating primarily involves returning the steam to the boiler's reheater for heating, thereby improving the unit's thermal efficiency and steam utilization. Currently, most steam reheat temperature control methods utilize a combination of flue gas damper adjustment and water spraying for desuperheating, employing conventional PID control methods. When the reheat steam overheats and the automatic desuperheating water adjustment mechanism is activated, the PID controller often injects excessive desuperheating water, which can easily cause the reheat steam temperature to underheat. Further adjustment of the flue gas damper at this point can easily cause the reheat steam temperature to oscillate between "overheat" and "underheat." Furthermore, excessive reheating desuperheating water spraying can reduce the unit's cycle thermal efficiency. For example, existing invention patent publication number CN109751590A discloses a double-reheat boiler and steam temperature control method. This method, by controlling the flue gas flow rate entering the boiler's tail flue, achieves more sensitive reheat steam temperature adjustment, reduces the frequency of burner swing angle fluctuations, and effectively regulates the reheat steam temperature. However, this method still fails to effectively address the oscillation problem. Summary of the Invention

[0003] In order to solve the above technical problems, the present invention proposes a reheat steam control method and system for a thermal power plant.

[0004] The technical solutions of the present invention are as follows:

[0005] The present invention proposes a reheat steam control system for a thermal power plant, comprising:

[0006] Reheat steam control module, used to centrally coordinate data distribution and decision execution;

[0007] Reheat steam temperature feedforward module, used to correct boiler air volume and fuel supply feedforward data in real time;

[0008] Reheat steam temperature control module, used to control the flue damper opening based on the mean reheater inlet temperature and to control the desuperheating water spray based on the outlet temperature deviation;

[0009] The reheat steam temperature feedforward module and the reheat steam temperature control module work together to control steam temperature fluctuations and improve the unit cycle thermal efficiency through real-time data correction and rapid response mechanism.

[0010] Preferably, the reheat steam temperature feedforward module includes:

[0011] The heating logic unit is used to calculate the theoretical supply values ​​of fuel and air volume required by the boiler according to the unit load instruction;

[0012] a first data transmission unit configured to bidirectionally transmit real-time data among the heat supply logic unit, the historical data logic unit, and the load feedforward unit;

[0013] a historical data logic unit configured to store and call historical operation data and provide a decision benchmark;

[0014] a load amount feedforward unit configured to predict a fuel demand variation trend according to a current unit load amount;

[0015] a load change instruction feedforward unit configured to generate an air volume adjustment feedforward signal in response to a load change instruction.

[0016] Preferably, the heat supply logic unit comprises a fuel supply subunit, an air volume supply subunit, and a heat supply data adjustment subunit, wherein:

[0017] the fuel supply subunit is configured to dynamically adjust a boiler fuel supply valve opening degree;

[0018] the air volume supply subunit is configured to control a boiler air blower rotation speed to adjust an air intake volume;

[0019] the heat supply data adjustment subunit is configured to correct a fuel and air volume supply ratio according to a decision feedback in real time.

[0020] Preferably, the historical data logic unit comprises a historical practice database subunit, an actual data subunit, a data comparison decision logic subunit, and a decision data feedback subunit, wherein:

[0021] the historical practice database subunit is configured to store a historical working condition flue damper opening degree record;

[0022] the actual data subunit is configured to collect a reheater inlet temperature real-time detection value;

[0023] the data comparison decision logic subunit is configured to match the real-time temperature average value with historical data and output an optimal damper opening degree value;

[0024] the decision data feedback subunit is configured to feed back the damper opening degree decision to the heat supply data adjustment subunit.

[0025] Preferably, the reheated steam temperature control module comprises:

[0026] a reheater inlet temperature detection unit configured to monitor a temperature of steam entering a reheater in real time;

[0027] a reheater inlet temperature average value calculation unit configured to calculate a sliding average value of multiple measurement point inlet temperatures;

[0028] a second data transmission unit configured to transmit the temperature average value to the historical data logic unit;

[0029] A reheater outlet temperature detection unit is configured to monitor the actual temperature of the steam leaving the reheater;

[0030] A damper opening degree regulation unit is configured to drive the flue damper actuator to the target opening degree;

[0031] A desuperheating water regulation unit is configured to control the opening and closing and opening degree of the desuperheating water spray valve.

[0032] Preferably, the desuperheating water regulation unit comprises a steam outlet temperature target threshold setting subunit, a steam outlet temperature deviation calculation subunit, a steam outlet temperature deviation correction subunit and a desuperheating water opening and closing module; wherein:

[0033] The steam outlet temperature target threshold setting subunit is configured to set the reheated steam outlet target temperature value;

[0034] The steam outlet temperature deviation calculation subunit is configured to calculate the real-time deviation of the actual steam outlet temperature from the target temperature;

[0035] The steam outlet temperature deviation correction subunit is configured to match the preset spray water parameter mapping table according to the deviation value;

[0036] The desuperheating water opening and closing subunit is configured to execute the opening and closing action of the spray valve.

[0037] In another aspect, the present application also provides a reheated steam control method for a thermal power plant, comprising the following steps:

[0038] The unit load instruction is received and distributed to the reheated steam temperature feedforward module and the reheated steam temperature control module through the reheated steam control module;

[0039] The theoretical supply value of the boiler air volume and fuel supply is calculated based on the unit load instruction through the reheated steam temperature feedforward module, and the historical operation data stored in the historical data logic unit is called, combined with the fuel demand trend predicted by the load amount feedforward unit, to dynamically correct the air volume and fuel supply feedforward data;

[0040] The corrected feedforward data is input into the reheated steam temperature control module, the optimal damper opening degree value of the historical practice database is matched based on the average value of the reheater inlet temperature, and the flue damper actuator is driven;

[0041] Based on the actual value of the reheater outlet temperature detection unit, the real-time deviation of the actual value from the target threshold value is calculated, the desuperheating water spray parameters are matched through the mapping table, and the valve opening degree and opening and closing time length are controlled;

[0042] Through the real-time correction data of the reheated steam temperature feedforward module and the damper opening degree and desuperheating water regulation of the reheated steam temperature control module, a closed-loop feedback is formed to suppress the steam temperature oscillation and improve the unit cycle thermal efficiency.

[0043] Preferably, the dynamic correction of the air volume and fuel supply feedforward data comprises:

[0044] The unit load instruction is decomposed by the heating logic unit to generate initial parameters of the fuel supply valve opening and the air supply fan speed;

[0045] The air volume adjustment feedforward compensation signal is generated by the load change rate responsive feedforward unit;

[0046] The final corrected air volume / fuel supply ratio is output by the heating data adjustment subunit by fusing the initial parameters, the compensation signal and the historical data comparison result.

[0047] Preferably, the mapping table comprises a plurality of set temperature value deviation corresponding desuperheating water opening and on-off time data.

[0048] Preferably, the closed-loop feedback specifically is that the decision data feedback subunit of the reheating steam temperature feedforward module feeds back the baffle opening decision obtained based on the historical data comparison to the heating data adjustment subunit for real-time correction of the air volume and fuel supply ratio; at the same time, the output of the desuperheating water regulation module is fed back to the reheating steam temperature feedforward module through the reheating steam control system end to update the data in the historical data logic unit.

[0049] The present application has the following beneficial effects:

[0050] 1. Through the dynamic correction (fuel / air volume ratio adjustment) of the feedforward module and the rapid response (baffle opening regulation + precise desuperheating water spraying) of the control module, the steam temperature fluctuation range is reduced from the traditional ±8℃ to ±2℃, and the oscillation problem caused by over-regulation and under-regulation is completely solved.

[0051] 2. The desuperheating water consumption is reduced by 18%, the steam thermal energy loss caused by spraying is reduced, the thermal efficiency is improved, and the steam work efficiency is maximized due to the stable temperature.

[0052] 3. Through the air volume compensation signal and the historical data prediction, the traditional control lag is eliminated, and the load mutation response delay is reduced.

[0053] 4. The inlet temperature mutation is monitored in real time, the baffle opening is forcibly locked in the safe interval, and the equipment overheating damage is effectively prevented. BRIEF DESCRIPTION OF DRAWINGS

[0054] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiments of the present application. It should be understood that the following drawings only show some embodiments of the present application, and therefore should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can also be obtained without creative labor on the basis of these drawings.

[0055] Figure 1 System operation logic diagram of the present application. DETAILED DESCRIPTION

[0056] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative effort belong to the scope of protection of the present application.

[0057] It should be understood that the step numbers used herein are only for the convenience of description, and are not limited to the execution sequence of the steps.

[0058] It should be understood that the terms used in the present application are only for the purpose of describing specific embodiments and are not intended to limit the present application. As used in the present application and the appended claims, unless otherwise clear from the context, the singular forms "a", "an" and "the" are intended to include the plural forms.

[0059] The terms "comprise" and "include" indicate the presence of described features, integers, steps, operations, elements, and / or components, but do not exclude one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0060] The term "and / or" means any combination of one or more of the associated listed items and all possible combinations, and includes these combinations.

[0061] Embodiment one:

[0062] In order to make the purposes, technical solutions and advantages of the present application clearer, specific embodiments of the present application will be described below, and the accompanying drawings will be referred to. Figure 1 The technical solutions of the present application are clearly and completely described.

[0063] To solve the problems in the prior art, the present application provides a reheated steam control system for a thermal power plant, comprising:

[0064] A reheated steam control module receives a unit load instruction and sends it to a reheated steam temperature feedforward module and a reheated steam temperature control module, respectively, for centralized coordination of data distribution and decision execution. In this embodiment, the reheated steam control module receives and analyzes instruction parameters, including load value and load change rate, and distributes load data to the reheated steam temperature feedforward module and the reheated steam temperature control module through a communication bus.

[0065] The decision execution is that when the reheating steam control module receives the load instruction, the air volume compensation signal output by the feedforward module and the real-time opening of the damper feedback by the temperature control module are obtained simultaneously, if the air volume compensation amplitude > 10% and the damper opening > 50% (indicating that the boiler burns violently), a desuperheating water pre-opening instruction (starting the water injection system 5 seconds in advance) is generated; and when the average value of the inlet temperature is detected to mutate, the damper opening instruction is immediately overwritten, and is forced to be locked in the safety interval.

[0066] The reheating steam temperature feedforward module is used for real-time correction of the boiler air volume and fuel supply feedforward data.

[0067] As a preferred embodiment of the present embodiment, the reheating steam temperature feedforward module comprises:

[0068] The heat supply logic unit is used for calculating the theoretical supply value of the fuel and air volume required by the boiler according to the unit load instruction; in the present embodiment, the heat supply logic unit calculates the theoretical value of the coal quantity and the theoretical value of the air volume of the boiler according to the load instruction;

[0069] The first data transmission unit is used for bidirectional transmission of real-time data among the heat supply logic unit, the historical data logic unit and the load feedforward unit; in the present embodiment, the first data transmission unit adopts a double-channel RS485 communication module (model ADM2587E) to connect the three units, and specifically includes a bidirectional channel between the heat supply logic unit and the historical data logic unit, which is used for transmitting real-time air and coal data, and a bidirectional channel between the heat supply logic unit and the load feedforward unit, which is used for transmitting load prediction data.

[0070] The historical data logic unit is used for storing and calling historical operation data, and providing a decision benchmark; the damper opening of the flue under the same load working condition in the historical database is called as a benchmark value according to the load instruction;

[0071] The load quantity feedforward unit is used for predicting the fuel demand change trend according to the current unit load quantity.

[0072] The load rise and fall instruction feedforward unit is used for generating an air volume adjustment feedforward signal in response to the load rise and fall instruction; specifically, the corresponding air volume compensation signal is generated according to the change amount of the load instruction.

[0073] As a preferred embodiment of the present embodiment, the heat supply logic unit comprises a fuel supply subunit, an air volume supply subunit and a heat supply data adjustment subunit, wherein:

[0074] The fuel supply subunit is used for dynamically adjusting the opening of the boiler fuel supply valve.

[0075] The air volume supply subunit is used for controlling the speed of the boiler air supply fan to adjust the air inlet volume.

[0076] A heat supply data adjustment subunit is configured to correct the fuel and air supply ratio in real time according to the decision feedback.

[0077] As a preferred embodiment of the present embodiment, the historical data logic unit comprises a historical practice database subunit, an actual data subunit, a data comparison decision logic subunit, and a decision data feedback subunit, wherein:

[0078] The historical practice database subunit is configured to store the records of the flue damper opening degree under historical working conditions.

[0079] The actual data subunit is configured to collect the real-time detection value of the reheater inlet temperature.

[0080] The data comparison decision logic subunit is configured to match the real-time temperature mean value with the historical data and output the optimal damper opening degree value.

[0081] The reheated steam temperature control module is configured to regulate the flue damper opening degree based on the reheater inlet temperature mean value and regulate the desuperheating water spraying based on the outlet temperature deviation.

[0082] As a preferred embodiment of the present embodiment, the reheated steam temperature control module comprises:

[0083] The reheater inlet temperature detection unit is configured to monitor the temperature of the steam entering the reheater in real time.

[0084] The reheater inlet temperature mean value calculation unit is configured to calculate the sliding mean value of the inlet temperature of multiple measuring points.

[0085] The second data transmission unit is configured to transmit the temperature mean value to the historical data logic unit.

[0086] The reheater outlet temperature detection unit is configured to monitor the actual temperature of the steam leaving the reheater.

[0087] The damper opening degree regulation unit is configured to drive the flue damper actuator to the target opening degree.

[0088] The desuperheating water regulation unit is configured to control the opening and closing and opening degree of the desuperheating water spraying valve.

[0089] As a preferred embodiment of the present embodiment, the desuperheating water regulation unit comprises a steam outlet temperature target threshold setting subunit, a steam outlet temperature deviation calculation subunit, a steam outlet temperature deviation correction subunit, and a desuperheating water on-off module, wherein:

[0090] The steam outlet temperature target threshold setting subunit is configured to set the reheated steam outlet target temperature value.

[0091] The steam outlet temperature deviation calculation subunit is configured to calculate the real-time deviation of the actual steam outlet temperature from the target temperature.

[0092] steam outlet temperature deviation correction subunit for matching a preset water injection parameter mapping table according to the deviation value;

[0093] temperature reducing water opening and closing subunit for executing water injection valve opening and closing actions.

[0094] The reheated steam temperature feedforward module and the reheated steam temperature control module work cooperatively, control steam temperature oscillation and improve unit cycle thermal efficiency through real-time data correction and fast response mechanism.

[0095] Embodiment two:

[0096] The embodiment provides a reheated steam control method for a thermal power plant, comprising the following steps:

[0097] The unit load instruction is received and distributed to the reheated steam temperature feedforward module and the reheated steam temperature control module through the reheated steam control module; specifically, the reheated steam control module receives the unit load instruction and analyzes instruction parameters, including a load value and a load change rate, distributes the instruction parameters to the reheated steam temperature feedforward module to start feedforward calculation and to the reheated steam temperature control module to prepare temperature regulation through a communication bus.

[0098] The reheated steam temperature feedforward module calculates the theoretical supply value of the boiler air volume and fuel supply based on the unit load instruction, and calls historical operation data stored in the historical data logic unit, combines the fuel demand trend predicted by the load amount feedforward unit, and dynamically corrects the air volume and fuel supply feedforward data; the specific steps are as follows:

[0099] The heat supply logic unit decomposes the load instruction to the fuel supply subunit and the air volume supply subunit to generate a valve opening degree theoretical value and a forced draught fan speed theoretical value;

[0100] The actual data subunit of the historical data logic unit collects the current inlet temperature, and the data comparison decision logic subunit outputs a damper opening degree reference value according to the matched historical database;

[0101] The load amount feedforward unit predicts the fuel demand in the future time; the load rise and fall instruction feedforward unit generates an air volume compensation signal in response to the load change rate;

[0102] The heat supply data adjustment subunit performs fusion calculation to dynamically correct the air volume and fuel supply feedforward data, specifically: final air-fuel ratio = (initial air-fuel ratio x 0.6) + (historical reference air-fuel ratio x 0.3) + (compensation coefficient x 0.1).

[0103] The corrected feedforward data is input into the reheated steam temperature control module, the optimal damper opening degree value of the historical practice database is matched based on the reheater inlet temperature average, and the flue damper actuator is driven;

[0104] Based on the actual value of the reheater outlet temperature detection unit, the real-time deviation of the actual value and the target threshold value is calculated, the desuperheating water spraying parameters are matched through the mapping table, and the valve opening degree and the opening and closing time are controlled.

[0105] Through the real-time correction data of the reheated steam temperature feedforward module and the baffle opening degree and the desuperheating water regulation of the reheated steam temperature control module, a closed loop feedback is formed, the steam temperature oscillation is suppressed, and the circulating thermal efficiency of the unit is improved.

[0106] As a preferred embodiment of the present embodiment, the dynamic correction of the air volume and the fuel supply feedforward data includes:

[0107] The heating logic unit decomposes the unit load instruction to generate the initial parameters of the fuel supply valve opening degree and the air supply fan speed;

[0108] The load change rate is responded by the load rise and fall instruction feedforward unit to generate the air volume adjustment feedforward compensation signal;

[0109] The initial parameters, the compensation signal and the historical data comparison result are fused by the heating data adjustment subunit to output the finally corrected air volume / fuel supply ratio.

[0110] As a preferred embodiment of the present embodiment, the mapping table includes a plurality of sets of temperature value deviation corresponding desuperheating water opening degree and opening and closing time data.

[0111] As a preferred embodiment of the present embodiment, the closed loop feedback is that the baffle opening degree decision feedback obtained based on the historical data comparison by the decision data feedback subunit of the reheated steam temperature feedforward module is fed back to the heating data adjustment subunit for real-time correction of the air volume and the fuel supply ratio; at the same time, the output of the desuperheating water regulation module is fed back to the reheated steam temperature feedforward module through the reheated steam control system end to update the data in the historical data logic unit.

[0112] In the embodiments of the present application, "at least one" means one or more, and "multiple" means two or more. The association relationship of the associated objects is described, which means that there can be three kinds of relationships, for example, A and / or B, which means that A exists alone, A and B exist together, and B exists alone. Wherein A, B can be singular or plural. The character " / " generally represents an "or" relationship between the front and rear associated objects. "At least one of the following" and the like means any combination of these items, including any combination of single or multiple items. For example, at least one of a, b and c can represent: a, b, c, a and b, a and c, b and c, or a and b and c, wherein a, b, c can be single or multiple.

[0113] Those skilled in the art will appreciate that the various units and algorithm steps described in the embodiments disclosed herein can be implemented using a combination of electronic hardware, computer software, and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professionals and technicians can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0114] Those skilled in the art will clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0115] In the several embodiments provided in this application, if any function is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, or the part that contributes to the prior art, or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes instructions for enabling a computer device (which can be a personal computer, server, or network device, etc.) to execute all or part of the steps of the method described in each embodiment of this application. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (Read-Only Memory; hereinafter referred to as: ROM), random access memory (Random Access Memory; hereinafter referred to as: RAM), disk or optical disk, and other media that can store program code.

[0116] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention's description and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A reheat steam control system for a thermal power plant, characterized in that: include: Reheat steam control module, used to centrally coordinate data distribution and decision execution; Reheat steam temperature feedforward module, used to correct boiler air volume and fuel supply feedforward data in real time; Reheat steam temperature control module, used to control the flue damper opening based on the mean reheater inlet temperature and to control the desuperheating water spray based on the outlet temperature deviation; The reheat steam temperature feedforward module and the reheat steam temperature control module work together to control steam temperature fluctuations and improve the unit cycle thermal efficiency through real-time data correction and rapid response mechanism.

2. A reheat steam control system for a thermal power plant according to claim 1, characterized in that: The reheat steam temperature feedforward module includes: The heating logic unit is used to calculate the theoretical supply values ​​of fuel and air volume required by the boiler according to the unit load instruction; A first data transmission unit is used for bidirectionally transmitting real-time data between the heating logic unit, the historical data logic unit and the load feedforward unit; Historical data logic unit, used to store and call historical operation data to provide a decision-making basis; Load feedforward unit, used to predict the fuel demand change trend based on the current unit load; The load increase / decrease instruction feedforward unit is used to respond to the load increase / decrease instruction and generate an air volume adjustment feedforward signal.

3. A reheat steam control system for a thermal power plant according to claim 2, characterized in that: The heating logic unit includes: a fuel supply subunit, an air volume supply subunit and a heating data adjustment subunit, wherein: The fuel supply subunit is used to dynamically adjust the opening of the boiler fuel supply valve; Air supply subunit, used to control the speed of the boiler blower to adjust the air intake volume; The heating data adjustment subunit is used to correct the fuel and air supply ratio in real time according to decision feedback.

4. A reheat steam control system for a thermal power plant according to claim 3, characterized in that: The historical data logic unit includes: a historical practice database subunit, an actual data subunit, a data comparison decision logic subunit and a decision data feedback subunit, wherein: The historical practice database subunit is used to store the flue damper opening records under historical working conditions; Actual data subunit, used to collect real-time detection values ​​of reheater inlet temperature; The data comparison and decision logic subunit is used to match the real-time temperature average with the historical data and output the optimal damper opening value; The decision data feedback subunit is used to feed back the damper opening decision to the heating data adjustment subunit.

5. The reheat steam control system of a thermal power plant according to claim 2, characterized in that: The reheat steam temperature control module includes: Reheater inlet temperature detection unit, used to monitor the temperature of steam entering the reheater in real time; Reheater inlet temperature mean calculation unit, used to calculate the sliding average of the inlet temperatures at multiple measuring points; A second data transmission unit is used to transmit the temperature average to the historical data logic unit; Reheater outlet temperature detection unit, used to monitor the actual temperature of steam leaving the reheater; The damper opening control unit is used to drive the flue damper actuator to the target opening; The cooling water control unit is used to control the opening and closing and opening degree of the cooling water spray valve.

6. A reheat steam control system for a thermal power plant according to claim 5, characterized in that: The attemperating water control unit includes: a steam outlet temperature target threshold setting subunit, a steam outlet temperature deviation calculation subunit, a steam outlet temperature deviation correction subunit and an attemperating water opening and closing module; wherein: The steam outlet temperature target threshold setting subunit is used to set the reheat steam outlet target temperature value; The steam outlet temperature deviation calculation subunit is used to calculate the real-time deviation between the actual steam outlet temperature and the target temperature; The steam outlet temperature deviation correction subunit is used to match the preset water spray parameter mapping table according to the deviation value; The cooling water opening and closing subunit is used to execute the opening and closing actions of the water spray valve.

7. A reheat steam control method for a thermal power plant, characterized in that: The following steps are involved: Receives unit load instructions and distributes them to the reheat steam temperature feedforward module and reheat steam temperature control module through the reheat steam control module; Based on the unit load command, the theoretical supply values ​​of boiler air volume and fuel supply are calculated through the reheat steam temperature feedforward module, and the historical operation data stored in the historical data logic unit are called. Combined with the fuel demand trend predicted by the load feedforward unit, the air volume and fuel supply feedforward data are dynamically corrected; The corrected feedforward data is input into the reheat steam temperature control module, and the optimal damper opening value based on the mean reheater inlet temperature is matched with the historical practice database to drive the flue damper actuator; Based on the actual value of the reheater outlet temperature detection unit, the real-time deviation between the actual value and the target threshold is calculated, and the desuperheating water spray parameters are matched through the mapping table to control the valve opening and opening and closing time; A closed-loop feedback is formed by the real-time correction data of the reheat steam temperature feedforward module and the damper opening and desuperheating water regulation of the reheat steam temperature control module to suppress steam temperature fluctuations and improve the unit cycle thermal efficiency.

8. The reheat steam control method for a thermal power plant according to claim 7, characterized in that: The dynamically corrected air volume and fuel supply feedforward data include: The heating logic unit decomposes the unit load command to generate the initial parameters of the fuel supply valve opening and the blower speed; The load lifting command feedforward unit responds to the load change rate and generates an air volume adjustment feedforward compensation signal; The heating data adjustment subunit fuses the initial parameters, compensation signals and historical data comparison results to output the final corrected air volume / fuel supply ratio.

9. The reheat steam control method for a thermal power plant according to claim 7, characterized in that: The mapping table includes multiple groups of desuperheating water opening degrees and opening and closing time data corresponding to set temperature value deviations.

10. The reheat steam control method for a thermal power plant according to claim 7, characterized in that: The closed-loop feedback is specifically as follows: the decision data feedback subunit of the reheat steam temperature feedforward module feeds back the damper opening decision obtained based on the historical data comparison to the heating data adjustment subunit, which is used to correct the air volume and fuel supply ratio in real time; at the same time, the output of the cooling water control module is fed back to the reheat steam temperature feedforward module through the reheat steam control system end to update the data in the historical data logic unit.

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