Adaptive start-stop control method of APS

Abstract

This invention belongs to the field of gas turbine control systems and proposes an APS adaptive start-stop control method, which includes multiple automatic control modules used to control the pre-start preparation, start-up, and shutdown of a gas-steam combined cycle unit. These automatic control modules include fully automatic bypass control, fully automatic condensate drainage control, automatic start-up exhaust control, automatic gas turbine start-up and load increase control, and automatic steam turbine start-up and load increase control. Start-up includes cold start (S1), warm start-up (S2), and hot start-up (S3). The APS logic automatically determines the unit's state (cold, warm, or hot) and adopts different start-up strategies, reducing human intervention. Safety assurance technologies under different states are also automated. Furthermore, the invention optimizes the unit's start-up process, reduces start-up time, and improves economic performance, making it suitable for large-scale deployment.

Description

Technical Field

[0001] This invention belongs to the field of gas turbine control systems, specifically combined cycle units, and particularly relates to an APS adaptive start-stop control method. Background Technology

[0002] In recent years, with the adjustment of the national energy structure, gas turbines and their combined cycle units have become a direction for the development of clean energy in the power system. To adapt to the frequent start-ups and shutdowns of gas-steam combined cycle units and to standardize unit operation, the implementation of Automatic Power Plant Start-up and Shutdown System (APS, also known as one-button start-up and shutdown) has become an inevitable trend in the automation development of thermal power plants. The realization of APS can improve the accuracy and standardization of unit start-up and shutdown, is an effective measure to truly achieve manpower reduction and efficiency improvement, and is an important indicator of a high level of automation in the unit. Combined cycle units with automatic start-stop control function can automatically start various auxiliary equipment according to the status of the process system and main and auxiliary equipment by simply pressing the start or stop button on the operator station display screen during startup. The relevant auxiliary equipment, gas turbine, waste heat boiler and steam turbine generator set will be started according to the predetermined program, so that the gas turbine and steam turbine can automatically increase speed, automatically connect to the grid, and automatically increase from the initial load to the predetermined target load. When the unit needs to be stopped, the unit will automatically reduce the load from full load according to the predetermined program and automatically stop the operation of the main and auxiliary equipment.

[0003] Existing APS control systems used in gas-fired combined cycle (GC) units suffer from low efficiency in starting and stopping under different conditions, such as cold, mild, and hot states. For example, patent CN201721595451.X discloses an APS control system for a GC unit, including a start-up control system and a shutdown control system. The start-up control system includes a coordination control system, a waste heat boiler system, a gas turbine generator system, a steam turbine auxiliary control system, a steam turbine generator system, and unit auxiliary systems. The waste heat boiler system includes a condensate control module, a feedwater control module, a desuperheating water control module, a steam drum water level control module, and unit auxiliary systems. The steam turbine generator system includes an excitation system. The unit auxiliary systems include an open / closed water system, unit auxiliary systems, and a cooling water system. This system not only achieves sequential control of the equipment but also realizes system automation and automatic activation and automatic setting of the CCS system, enabling smooth start-up and shutdown of the unit. However, it also suffers from low start-up and shutdown efficiency under different conditions, and the bypass wastes a lot of steam during startup, resulting in a long warm-up time for the turbine, which affects the actual startup time of the unit and is not conducive to improving the unit's economic efficiency. Secondly, during cold startup, the temperature difference between the upper and lower parts of the boiler's high-pressure steam drum seriously affects the boiler's safety and lifespan. Summary of the Invention

[0004] This invention addresses the technical problems existing in the APS control system of the aforementioned gas-steam combined cycle unit by proposing an APS adaptive start-stop control method that is rationally designed, highly safe, optimizes the unit's start-up process, reduces the unit's start-up time, and improves the unit's economic performance.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows: the APS adaptive start-stop control method provided by the present invention includes multiple automatic control modules used to control the pre-start preparation, start-up and shutdown of the gas-steam combined cycle unit. The multiple automatic control modules include bypass fully automatic control, condensate fully automatic control, start-up exhaust automatic control, gas turbine start-up and load increase automatic control, and steam turbine start-up and load increase automatic control. The start-up includes cold start S1, warm start S2 and hot start S3.

[0006] The control steps for the cold start S1 are as follows:

[0007] S101, after the gas turbine reaches a constant speed and is connected to the grid, maintains a 10MW load, and the gas turbine load is stable;

[0008] S102. Take control measures for the upper and lower wall temperatures of the boiler high-pressure steam drum, namely, fully open the high-pressure bypass, control the pressure of the medium-pressure bypass at 0.5MPa, and start the exhaust steam and keep it open; after the lower wall temperature of the high-pressure steam drum is >150℃, switch the high-pressure bypass to the control pressure of 6.5MPa, control the pressure of the medium-pressure bypass to 1.2MPa, and control the main steam temperature at 400℃.

[0009] S103. Perform the turbine start-up operation on the SGC subgroup, and connect the turbine to the grid with a load of 20MW after the turbine reaches a constant speed of 3000rpm.

[0010] S104. Enter the gas turbine and steam turbine load matching control. When the steam turbine load increase is locked, the gas turbine load increase is also locked. After the steam turbine load increase lock is released, the load continues to increase. After the gas turbine load increases to 80MW, wait for the steam turbine to enter the following mode. At this time, the bypass enters the backup mode. Finally, after the gas turbine load increases to the total gas turbine and steam turbine load of 402MW, the coordination and AGC control are put into operation.

[0011] The control steps for the temperature start-up S2 are as follows:

[0012] S201, after the gas turbine reaches a constant speed and is connected to the grid, maintains a 30MW load, and the gas turbine load is stable;

[0013] S202. During the gas turbine startup process, the boiler automatically drains water, the high-pressure bypass control pressure is 8.0MPa, the medium-pressure bypass pressure is controlled to 1.4MPa, and the main steam temperature is controlled to the optimal start-up parameters.

[0014] S203. Perform the SGC operation to start the steam turbine, and connect the steam turbine to the grid with a load of 20MW after the turbine reaches a constant speed of 3000rpm.

[0015] S204. Enter the gas turbine and steam turbine load matching control. After the gas turbine load is increased to 80MW, wait for the steam turbine to enter the following mode. At this time, the bypass enters the backup mode. Finally, after the gas turbine load is increased to the total load of gas turbine and steam turbine of 402MW, coordination and AGC control are put into operation.

[0016] The control steps for the hot start S3 are as follows:

[0017] S301, after the gas turbine reaches a constant speed and is connected to the grid, it maintains a 50MW load and the gas turbine load is stable;

[0018] S302. During the gas turbine startup process, the boiler automatically drains water, the high-pressure bypass control pressure is 8.0MPa, the medium-pressure bypass pressure is controlled to 1.6MPa, and the main steam temperature is controlled to the optimal startup parameters.

[0019] S303, Perform the SGC operation to start the steam turbine, and connect the steam turbine to the grid with a load of 20MW after the turbine reaches a constant speed of 3000rpm;

[0020] S304. Enter the gas turbine and steam turbine load matching control. After the gas turbine load increases to 80MW, wait for the steam turbine to enter the following mode. At this time, the bypass enters the backup mode. Finally, after the gas turbine load increases to the total gas turbine and steam turbine load of 402MW, the coordination and AGC control are put into operation.

[0021] Preferably, in the cold start step S102, the boiler protection mechanism is triggered when the temperature difference between the upper and lower walls of the boiler high-pressure steam drum exceeds 30°C. The boiler protection mechanism is that the bypass is slowly opened to full opening, the boiler side starts exhaust steam and keeps it fully open as the wall temperature continues to increase, and participates in pressure control. When the upper and lower wall temperatures drop back to normal, the bypass is switched to the control start-up parameters, and the exhaust steam is fully closed.

[0022] Preferably, in the boiler protection mechanism, the gas turbine locks out the load increase and drainage system.

[0023] As a preferred option, during the intermediate-pressure steam connection process, the intermediate-pressure superheater is activated with fully automatic exhaust control, and remains open until steam connection is not achieved, ensuring a certain flow rate in the intermediate-pressure steam drum, and then closed after steam connection is achieved.

[0024] Preferably, the startup sequence includes 5 breakpoints, which are as follows:

[0025] Breakpoint 1 is a system preparation breakpoint. Breakpoint 1 includes 5 sub-functional groups. The breakpoint 1 completion conditions include: 1a - Closed water system startup completed; 1b - Open water system startup completed; 1c - Circulating water system startup completed; 1d - Lubricating oil system startup completed; 1e - EH oil system startup completed.

[0026] Breakpoint 2, waste heat boiler water supply breakpoint, comprising 7 sub-functional groups, the completion conditions of breakpoint 2 include: 2a - condensate system startup completed; 2b - auxiliary steam system in operation; 2c - low-pressure steam drum water level meets startup requirements; 2d - medium-pressure steam drum water level meets startup requirements; 2e - high-pressure steam drum water level meets startup requirements; 2f - shaft seal system in operation; 2g - vacuum system in operation;

[0027] Breakpoint 3, gas turbine start-up and grid connection breakpoint, includes 5 sub-functional groups, and the completion conditions of breakpoint 3 include: 3a-gas turbine is running with initial load, 3b-turbine start-up parameters meet requirements, 3c-bypass automatic status and set value automatically follows;

[0028] Breakpoint 4, turbine start-up and grid connection breakpoint, the breakpoint 4 includes 3 sub-functional groups, the completion conditions of the breakpoint 4 include: 4a - turbine 3000rpm and with initial load;

[0029] Breakpoint 5, load increase breakpoint, includes 3 sub-functional groups, and the conditions for completing breakpoint 5 include: 5a - HP / IP / LP pressure control has been put into operation and the automatic pressure setpoint has been given; 5b - CCS has been put into operation; 5c - Auxiliary steam source switching is completed; 5d - Breakpoint setting of unit-level APS startup process.

[0030] The shutdown sequence includes three breakpoints, which are as follows:

[0031] Breakpoint 6, load reduction breakpoint, has 4 sub-functional groups. The completion conditions of breakpoint 6 include 6a-AGC, primary frequency regulation and CCS mode exit; 6b-gas turbine reduced to shutdown load; 6c-auxiliary steam source switching completed;

[0032] Breakpoint 7, turbine disconnection breakpoint, the breakpoint 7 is set with 2 sub-functional groups, the completion conditions of the breakpoint 7 include: 7a- turbine load is less than 15MW; 7b- the trip signal disappears;

[0033] Breakpoint 8, gas turbine disconnection breakpoint, is set with 4 sub-functional groups. The completion conditions of breakpoint 8 include: 8a - all high and medium pressure feedwater pumps stop; 8b - waste heat boiler shutdown water level;

[0034] Breakpoint 9 is the unit shutdown breakpoint. Breakpoint 9 has 3 sub-functional groups. The objectives of the completion conditions of breakpoint 9 include: 9a - vacuum removal and shaft sealing system; 9b - complete shutdown of condensate pumps.

[0035] Preferably, the specific steps of the startup sequence are as follows:

[0036] Q101. Start the closed-loop cooling water system subroutine group, and after the closed-loop cooling water system is running, delay for 60 seconds;

[0037] Q102. Start the air compressor programmable command to ensure normal compressed air supply;

[0038] Q103. Start the circulating water system subroutine group, and after the circulating water system starts running, delay for 60 seconds;

[0039] Q104. Manually confirm that water injection and drainage are complete;

[0040] Q105. Start the open circulating water subroutine group, and after the open circulating water system starts running, delay for 60 seconds.

[0041] Q106, Unit startup preparation completed breakpoint;

[0042] Q107. Start the turbine auxiliary system, and delay the turbine auxiliary system for 60 seconds during startup.

[0043] Q108. Start the condensate system subroutine group, and after the condensate system starts running, delay for 60 seconds;

[0044] Q109. The auxiliary steam system is normal and the shaft seal can be activated. The shaft seal system is normal and the DEH allows vacuuming.

[0045] Q110. Start the vacuum system, ensure it is functioning normally, and delay for 60 seconds.

[0046] Q111. Start the condensate heater system subroutine group to indicate that the condensate heater system is running, with a delay of 60 seconds;

[0047] Q112. Start the low-pressure steam drum feedwater system subroutine group to ensure that the low-pressure steam drum feedwater system subroutine group is running;

[0048] Q113, The low-pressure steam drum reaches the start-up water level SP1;

[0049] Q114. Start the medium-pressure steam drum feedwater system subroutine group until it is running;

[0050] Q115. The medium-pressure steam drum has reached the start-up water level SP1 or the waste heat boiler is in operation.

[0051] Q116. Start the high-pressure steam drum feedwater system subroutine group until it is running;

[0052] Q117. The high-pressure steam drum has reached the start-up water level SP1 or the waste heat boiler is in operation;

[0053] Q118. Steam turbine auxiliary system startup complete, steam turbine ready to start confirmation;

[0054] Q119. Start the steam turbine system and allow it to start up.

[0055] Q120. Open the flue gas damper at the outlet of the waste heat boiler, indicating that the flue gas damper at the outlet of the waste heat boiler is open; gas turbine ready signal; gas turbine ready to start confirmation;

[0056] Q121. Start the gas turbine system and allow it to start up.

[0057] Q122. Start the low-pressure steam system subroutine group until it is started;

[0058] Q123. Start the medium-pressure steam system subroutine group until it is started;

[0059] Q124. Start the high-pressure steam system subroutine group until it is started;

[0060] Q125. The gas turbine generator has been connected to the grid.

[0061] Q126. The steam turbine generator has been connected to the grid;

[0062] Q127, Load increase confirmed;

[0063] Q128, Investment Coordination;

[0064] Q129. The target load is delivered to the gas turbine, and the total load of the unit reaches the target load;

[0065] Q130, Combined cycle startup complete.

[0066] Preferably, the shutdown sequence includes the following specific steps:

[0067] T201: Issue the AGC exit command and indicate that the AGC has exited;

[0068] T202, reduce the gas turbine load to the lower limit of AGC;

[0069] T203: Unit primary frequency regulation has been disabled; CCS has been disabled.

[0070] T204, Auxiliary steam source switching has been completed;

[0071] T205, reduce the gas turbine load to shutdown load;

[0072] T206, Start the turbine shutdown control program (TCS); High and medium pressure control have been deactivated; Turbine load <15MW; Brake signal lost; Turning gear engaged; Turbine shutdown control program completed;

[0073] T207, Start-up of gas turbine shutdown control program (TCS) has been completed; gas turbine has been extinguished;

[0074] T208, the high, medium and low pressure feedwater systems of the waste heat boiler have been shut down; all steam bypasses have been closed for 15 minutes.

[0075] T210, Stop the condensate heater system until it is already shut down;

[0076] T211. Start the vacuum system and complete the shutdown procedure.

[0077] T212. Start the turbine auxiliary system shutdown procedure until completion;

[0078] T213. Stop the condensate system until it is already shut down;

[0079] T215, The flue gas damper at the outlet of the waste heat boiler is closed;

[0080] T216, APS shutdown procedure completed.

[0081] Compared with the prior art, the advantages and positive effects of the present invention are as follows:

[0082] 1. The APS adaptive start-stop control method provided by this invention, in addition to realizing one-button start-up and reducing the intervention of operators, allows the APS to adopt different start-up strategies according to the unit status (cold, warm, hot), reducing the need for manual judgment and realizing fully automatic one-button start-stop of the APS under different conditions, which is conducive to improving the control efficiency of the system.

[0083] 2. The APS adaptive start-stop control method provided by this invention achieves safety through automation. For example, during cold start-up, when the temperature difference between the upper and lower walls of the boiler high-pressure steam drum exceeds 30°C, the boiler protection mechanism is triggered. The bypass slowly opens fully based on the temperature difference between the upper and lower walls. The boiler-side start-up exhaust remains fully open as the wall temperature continues to increase, participating in pressure control. When the upper and lower wall temperatures return to normal, the bypass switches to the control startup parameters, and the start-up exhaust is completely shut off. In addition, the gas turbine also implements measures such as locking up load increases and draining to ensure boiler safety. The intermediate-pressure steam connection safety measures are automated. To ensure that the intermediate-pressure superheater temperature matches the reheater temperature during steam connection, the intermediate-pressure superheater start-up exhaust is fully automatically controlled, remaining open until steam connection is achieved to ensure a certain flow rate in the intermediate-pressure steam drum, and closing after steam connection. Automatic draining control is implemented during warm start-up of the unit to prevent water hammer in the boiler piping.

[0084] 3. The APS adaptive start-stop control method provided by this invention reduces unit start-up time and improves unit economic performance. For example, it automatically controls start-up parameters, selecting different start-up parameters for cold, warm, and hot states, reducing warm-up time during start-up; it automatically matches the gas turbine and steam turbine loads under different operating conditions, controlling the load matching of the gas turbine during steam turbine start-up and grid connection, reducing steam waste during bypass start-up, and similarly reducing steam turbine warm-up time through appropriate temperature control, thus reducing unit start-up time.

[0085] This invention is reasonably designed, highly safe, optimizes the unit's startup process, reduces the unit's startup time, and improves the unit's economic performance, making it suitable for large-scale promotion. Detailed Implementation

[0086] To better understand the above-mentioned objectives, features, and advantages of the present invention, the following embodiments further illustrate the invention. It should be noted that, unless otherwise specified, the embodiments and features described in these embodiments can be combined with each other.

[0087] Numerous specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways than those described herein, and therefore the invention is not limited to the specific embodiments disclosed in the following specification.

[0088] This invention utilizes two Siemens SGT5-8000H heavy-duty gas turbines, paired with two Siemens SST5-5000 steam turbines, forming two "one-to-one" multi-shaft gas-steam combined cycle units. Specifically, one gas turbine generator unit is paired with one waste heat boiler, and one waste heat boiler supplies steam to one extraction-condensing steam turbine generator unit. A flue gas denitrification device is constructed simultaneously. This invention employs two DCS systems, specifically the maxDNA system from Nanjing Guodian NARI Valmet Automation Co., Ltd. maxDNA is a mature and reliable large-scale distributed control system with independent intellectual property rights owned by NARI Valmet. This system realizes all functions from the bottom-level I / O to controllers, third-party communication access, industrial process monitoring and control, to the top-level performance calculation, information management, and factory management, making it a complete distributed control system and information management system. The maxDNA system mainly consists of three parts: a communication network, workstations, and control stations.

[0089] Based on this, the APS adaptive start-stop control method provided by the present invention includes multiple automatic control modules and is used to control the pre-start preparation, start-up and shutdown of the gas-steam combined cycle unit. The multiple automatic control modules include bypass fully automatic control, condensate fully automatic control, start-up exhaust automatic control, gas turbine start-up and load increase automatic control, and steam turbine start-up and load increase automatic control. The start-up includes cold start S1, warm start S2 and hot start S3.

[0090] Specifically, the control steps for the cold start S1 are as follows:

[0091] S101, after the gas turbine reaches a constant speed and is connected to the grid, maintains a 10MW load, and the gas turbine load is stable;

[0092] S102. Take control measures for the upper and lower wall temperatures of the boiler high-pressure steam drum, namely, fully open the high-pressure bypass, control the pressure of the medium-pressure bypass at 0.5MPa, and start the exhaust steam and keep it open; after the lower wall temperature of the high-pressure steam drum is >150℃, switch the high-pressure bypass to the control pressure of 6.5MPa, control the pressure of the medium-pressure bypass to 1.2MPa, and control the main steam temperature at 400℃.

[0093] S103. Perform the turbine start-up operation on the SGC subgroup, and connect the turbine to the grid with a load of 20MW after the turbine reaches a constant speed of 3000rpm.

[0094] S104. Enter the gas turbine and steam turbine load matching control. When the steam turbine load increase is locked, the gas turbine load increase is also locked. After the steam turbine load increase lock is released, the load continues to increase. After the gas turbine load increases to 80MW, wait for the steam turbine to enter the following mode. At this time, the bypass enters the backup mode. Finally, after the gas turbine load increases to the total gas turbine and steam turbine load of 402MW, the coordination and AGC control are put into operation.

[0095] The control steps for the temperature start-up S2 are as follows:

[0096] S201, after the gas turbine reaches a constant speed and is connected to the grid, maintains a 30MW load, and the gas turbine load is stable;

[0097] S202. During the gas turbine startup process, the boiler automatically drains water, the high-pressure bypass control pressure is 8.0MPa, the medium-pressure bypass pressure is controlled to 1.4MPa, and the main steam temperature is controlled to the optimal start-up parameters.

[0098] S203. Perform the SGC operation to start the steam turbine, and connect the steam turbine to the grid with a load of 20MW after the turbine reaches a constant speed of 3000rpm.

[0099] S204. Enter the gas turbine and steam turbine load matching control. After the gas turbine load is increased to 80MW, wait for the steam turbine to enter the following mode. At this time, the bypass enters the backup mode. Finally, after the gas turbine load is increased to the total load of gas turbine and steam turbine of 402MW, coordination and AGC control are put into operation.

[0100] The control steps for hot start of S3 are as follows:

[0101] S301, after the gas turbine reaches a constant speed and is connected to the grid, it maintains a 50MW load and the gas turbine load is stable;

[0102] S302. During the gas turbine startup process, the boiler automatically drains water, the high-pressure bypass control pressure is 8.0MPa, the medium-pressure bypass pressure is controlled to 1.6MPa, and the main steam temperature is controlled to the optimal startup parameters.

[0103] S303, Perform the SGC operation to start the steam turbine, and connect the steam turbine to the grid with a load of 20MW after the turbine reaches a constant speed of 3000rpm;

[0104] S304. Enter the gas turbine and steam turbine load matching control. After the gas turbine load increases to 80MW, wait for the steam turbine to enter the following mode. At this time, the bypass enters the backup mode. Finally, after the gas turbine load increases to the total gas turbine and steam turbine load of 402MW, the coordination and AGC control are put into operation.

[0105] In addition to enabling one-button start-up and reducing human intervention, the APS logic of this invention can automatically determine the unit's status (cold, warm, hot). This invention provides different start-up strategies for different statuses, such as S1, S2, and S3, further reducing manual judgment and achieving fully automatic one-button start-up and shutdown under different conditions, which is beneficial to improving system control efficiency. Furthermore, during cold start-up (S1), warm start-up (S2), and hot start-up (S3), the start-up parameters are automatically controlled, especially using different optimal start-up parameters under cold, warm, and hot conditions, reasonably reducing warm-up time. The gas turbine and steam turbine loads are automatically matched under different operating conditions, controlling the load matching of the gas turbine during steam turbine start-up and grid connection, reducing steam waste during bypass startup, and similarly reducing steam turbine warm-up time and unit startup time through appropriate temperature control. Under different operating conditions (cold, warm, hot), the time from the gas turbine issuing the start-up command to the AGC automatic power generation control activation is approximately 4 hours, 2 hours, and 1 hour, respectively. The reduction in unit warm-up and startup time improves the unit's economic performance.

[0106] Furthermore, in the cold start-up step S102 of this invention, the boiler protection mechanism is triggered when the temperature difference between the upper and lower walls of the high-pressure steam drum exceeds 30°C. This boiler protection mechanism is controlled by fully automatic bypass control and automatic start-up exhaust control. For example, the bypass slowly opens to full opening based on the temperature difference between the upper and lower walls of the high-pressure steam drum. The boiler-side start-up exhaust remains fully open as the wall temperature continues to increase, participating in pressure control. When the upper and lower wall temperatures return to normal, the bypass switches to the control startup parameters, and the start-up exhaust is fully closed. In addition, the boiler protection mechanism includes measures such as gas turbine load increase lockout and condensate drainage to ensure boiler safety. Furthermore, the intermediate-pressure steam connection safety measures are also automated. For example, to ensure that the intermediate-pressure superheater temperature matches the reheater temperature during steam connection, the intermediate-pressure superheater start-up exhaust is fully automatically controlled, remaining open until steam connection is achieved, ensuring a certain flow rate in the intermediate-pressure steam drum, and closing after steam connection. Automatic condensate drainage control during warm start-up ensures that water hammer does not occur in the boiler piping. In this way, automation by adopting safety assurance technologies can improve the safe operation performance of the unit and effectively extend the actual service life of some equipment.

[0107] The startup sequence includes 5 breakpoints, which are as follows:

[0108] Breakpoint 1 is a system preparation breakpoint. Breakpoint 1 includes 5 sub-functional groups. The breakpoint 1 completion conditions include: 1a - closed water system startup completed; 1b - open water system startup completed; 1c - circulating water system startup completed; 1d - lubricating oil system startup completed; 1e - EH oil system startup completed. Breakpoint 1 is used to put the relevant auxiliary systems into a ready state before the entire unit is started.

[0109] Breakpoint 2, waste heat boiler water supply breakpoint, includes 7 sub-functional groups. The completion conditions of breakpoint 2 include: 2a - condensate system startup completed; 2b - auxiliary steam system in operation; 2c - low-pressure steam drum water level meets startup requirements; 2d - medium-pressure steam drum water level meets startup requirements; 2e - high-pressure steam drum water level meets startup requirements; 2f - shaft sealing system in operation; 2g - vacuum system in operation. Breakpoint 2 is used to ensure that the water levels of the three main steam drums of the unit meet the startup requirements through automatic logic, and to automatically put the shaft sealing system and vacuum system into operation.

[0110] Breakpoint 3, gas turbine start-up and grid connection breakpoint, includes 5 sub-functional groups. The completion conditions of breakpoint 3 include: 3a - gas turbine is running with initial load, 3b - steam turbine start-up parameters meet requirements, 3c - bypass automatic state and set value automatically follows; breakpoint 3 is used to enable gas turbine start-up ignition with initial load, and during the process, the low-pressure, medium-pressure and high-pressure main steam system heating and pressurization circuits are automatically engaged.

[0111] Breakpoint 4, turbine start-up and grid connection breakpoint, the breakpoint 4 includes 3 sub-functional groups, the completion conditions of the breakpoint 4 include: 4a - turbine 3000rpm and with initial load; breakpoint 4 is used to start the turbine and connect it to the grid with initial load.

[0112] Breakpoint 5, the load increase breakpoint, includes 3 sub-functional groups. The conditions for completing breakpoint 5 include: 5a - HP / IP / LP pressure control is already in operation and the automatic pressure setpoint has been given; 5b - CCS is already in operation; 5c - Auxiliary steam source switching is completed; 5d - Breakpoint setting for the unit-level APS startup process. Breakpoint 5 is used to ensure that after both the gas turbine and steam turbine are under initial load, the APS will drive the load increase process throughout until the CCS is in operation. During the process, it has the function of adaptive operation conditions, setting different parameters according to cold, warm, and hot states to meet the conditions for safe and stable operation of the unit.

[0113] The shutdown sequence includes three breakpoints, which are as follows:

[0114] Breakpoint 6, load reduction breakpoint, has 4 sub-functional groups. The completion conditions of breakpoint 6 include 6a-AGC, primary frequency regulation and CCS mode exit; 6b-gas turbine reduced to shutdown load; 6c-auxiliary steam source switching completed. Breakpoint 6 is used to make the unit exit AGC mode from the current load, then reduce the load until exiting CCS, switch the auxiliary steam source, and finally reduce the load to the gas turbine shutdown load.

[0115] Breakpoint 7, turbine disconnection breakpoint, has two sub-functional groups. The conditions for breaking point 7 to be completed include: 7a - turbine load is less than 15MW; 7b - the tripping signal disappears. Breakpoint 7 is used to allow the unit to switch from CCS mode to turbine coasting after the gas turbine is reduced to the design load and then put into turning gear mode.

[0116] Breakpoint 8 is a gas turbine disconnection breakpoint. Breakpoint 8 has 4 sub-functional groups. The conditions for breakingpoint 8 to be completed include: 8a - all high and medium pressure feedwater pumps stop; 8b - waste heat boiler shutdown water level. Breakpoint 8 is used to make the gas turbine execute the shutdown order, and at the same time the boiler equipment starts to operate to achieve the purpose of heat preservation and pressure preservation.

[0117] Breakpoint 9 is the unit shutdown breakpoint. Breakpoint 9 has three sub-functional groups. The objectives of breakingpoint 9 include: 9a - vacuum release and shaft seal system shutdown; 9b - complete shutdown of condensate pumps. Breakpoint 9 is used to break the vacuum of the unit, release the shaft seal system, and then shut down the condensate system.

[0118] The specific steps of the startup sequence are as follows:

[0119] Q101. Start the closed-loop cooling water system subroutine group, and after the closed-loop cooling water system is running, delay for 60 seconds;

[0120] Q102. Start the air compressor programmable command to ensure normal compressed air supply;

[0121] Q103. Start the circulating water system subroutine group, and after the circulating water system starts running, delay for 60 seconds;

[0122] Q104. Manually confirm that water injection and drainage are complete;

[0123] Q105. Start the open circulating water subroutine group, and after the open circulating water system starts running, delay for 60 seconds.

[0124] Q106, Unit startup preparation completed breakpoint;

[0125] Q107. Start the turbine auxiliary system, and delay the turbine auxiliary system for 60 seconds during startup.

[0126] Q108. Start the condensate system subroutine group, and after the condensate system starts running, delay for 60 seconds;

[0127] Q109. The auxiliary steam system is normal and the shaft seal can be activated. The shaft seal system is normal and the DEH allows vacuuming.

[0128] Q110. Start the vacuum system, ensure it is functioning normally, and delay for 60 seconds.

[0129] Q111. Start the condensate heater system subroutine group to indicate that the condensate heater system is running, with a delay of 60 seconds;

[0130] Q112. Start the low-pressure steam drum feedwater system subroutine group to ensure that the low-pressure steam drum feedwater system subroutine group is running;

[0131] Q113, The low-pressure steam drum reaches the start-up water level SP1;

[0132] Q114. Start the medium-pressure steam drum feedwater system subroutine group until it is running;

[0133] Q115. The medium-pressure steam drum has reached the start-up water level SP1 or the waste heat boiler is in operation.

[0134] Q116. Start the high-pressure steam drum feedwater system subroutine group until it is running;

[0135] Q117. The high-pressure steam drum has reached the start-up water level SP1 or the waste heat boiler is in operation;

[0136] Q118. Steam turbine auxiliary system startup complete, steam turbine ready to start confirmation;

[0137] Q119. Start the steam turbine system and allow it to start up.

[0138] Q120. Open the flue gas damper at the outlet of the waste heat boiler, indicating that the flue gas damper at the outlet of the waste heat boiler is open; gas turbine ready signal; gas turbine ready to start confirmation;

[0139] Q121. Start the gas turbine system and allow it to start up.

[0140] Q122. Start the low-pressure steam system subroutine group until it is started;

[0141] Q123. Start the medium-pressure steam system subroutine group until it is started;

[0142] Q124. Start the high-pressure steam system subroutine group until it is started;

[0143] Q125. The gas turbine generator has been connected to the grid.

[0144] Q126. The steam turbine generator has been connected to the grid;

[0145] Q127, Load increase confirmed;

[0146] Q128, Investment Coordination;

[0147] Q129. The target load is delivered to the gas turbine, and the total load of the unit reaches the target load;

[0148] Q130, Combined cycle startup complete.

[0149] The shutdown procedure includes the following specific steps:

[0150] T201: Issue the AGC exit command and indicate that the AGC has exited;

[0151] T202, reduce the gas turbine load to the lower limit of AGC;

[0152] T203: Unit primary frequency regulation has been disabled; CCS has been disabled.

[0153] T204, Auxiliary steam source switching has been completed;

[0154] T205, reduce the gas turbine load to shutdown load;

[0155] T206, Start the turbine shutdown control program (TCS); High and medium pressure control have been deactivated; Turbine load <15MW; Brake signal lost; Turning gear engaged; Turbine shutdown control program completed;

[0156] T207, Start-up of gas turbine shutdown control program (TCS) has been completed; gas turbine has been extinguished;

[0157] T208, the high, medium and low pressure feedwater systems of the waste heat boiler have been shut down; all steam bypasses have been closed for 15 minutes.

[0158] T210, Stop the condensate heater system until it is already shut down;

[0159] T211. Start the vacuum system and complete the shutdown procedure.

[0160] T212. Start the turbine auxiliary system shutdown procedure until completion;

[0161] T213. Stop the condensate system until it is already shut down;

[0162] T215, The flue gas damper at the outlet of the waste heat boiler is closed;

[0163] T216, APS shutdown procedure completed.

[0164] The startup and shutdown sequences include instruction issuance and execution feedback. After the previous instruction is issued, the system waits for execution feedback before proceeding to the next instruction. The orderly issuance of instructions and execution feedback ensures the high efficiency of APS startup and shutdown. In particular, it can adapt to the startup requirements of this invention under different operating conditions, namely cold, mild and hot conditions. The logic of APS provides an effective basis for the adaptive design of this invention, enabling the combined cycle unit applied by this invention to have better safety and economic performance.

[0165] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any other way. Any person skilled in the art may make changes or modifications to the above-disclosed technical content to create equivalent embodiments for application in other fields. However, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the protection scope of the present invention.

Claims

1. An APS adaptive start-stop control method, comprising a plurality of automatic control modules and used to control the start-up preparation, start-up and shutdown of a gas-steam combined cycle unit, the plurality of automatic control modules comprising bypass full-automatic control, drainage full-automatic control, start-up exhaust automatic control, gas turbine start-up and load increase automatic control, steam turbine start-up and load increase automatic control, characterized in that: The starting includes cold starting S1, warm starting S2 and hot starting S3, The control steps of the cold starting S1 are as follows: S101, after the gas turbine is set at a speed, grid connection is made, 10MW load is kept, and the gas turbine load is stable; S102, the upper and lower wall temperatures of the boiler high-pressure drum are controlled, that is, the high-pressure bypass is fully opened, the medium-pressure bypass pressure is controlled at 0.5MPa, and the starting exhaust is kept open; after the lower wall temperature of the high-pressure drum is greater than 150℃, the high-pressure bypass is cut to pressure control at 6.5MPa, the medium-pressure bypass pressure is controlled at 1.2MPa, and the main steam temperature is controlled at 400℃; S103, SGC sub-group operation is performed for turbine rush, the turbine is set at a speed of 3000rpm, grid connection is made, and 20MW load is carried; S104, gas turbine and turbine load matching control is entered, when the turbine load is closed, the gas turbine load is also closed, after the turbine load is closed, the load is continuously increased, after the gas turbine load is increased to 80MW, the turbine enters the following mode, at this time, the bypass enters the backup mode, finally, the gas turbine load is increased to the total load of 402MW, and the coordination and AGC control is put into operation; The control steps of the warm starting S2 are as follows: S201, after the gas turbine is set at a speed, grid connection is made, 30MW load is kept, and the gas turbine load is stable; S202, during the gas turbine starting process, the boiler automatically drains, the high-pressure bypass pressure is controlled at 8.0MPa, the medium-pressure bypass pressure is controlled at 1.4MPa, and the main steam temperature is controlled at the optimal rush parameter; S203, SGC operation is performed for turbine rush, the turbine is set at a speed of 3000rpm, grid connection is made, and 20MW load is carried; S204, gas turbine and turbine load matching control is entered, after the gas turbine load is increased to 80MW, the turbine enters the following mode, at this time, the bypass enters the backup mode, finally, the gas turbine load is increased to the total load of 402MW, and the coordination and AGC control is put into operation; The control steps of the hot starting S3 are as follows: S301, after the gas turbine is set at a speed, grid connection is made, 50MW load is kept, and the gas turbine load is stable; S302, during the gas turbine starting process, the boiler automatically drains, the high-pressure bypass pressure is controlled at 8.0MPa, the medium-pressure bypass pressure is controlled at 1.6MPa, and the main steam temperature is controlled at the optimal rush parameter; S303, SGC operation is performed for turbine rush, the turbine is set at a speed of 3000rpm, grid connection is made, and 20MW load is carried; S304, gas turbine and turbine load matching control is entered, after the gas turbine load is increased to 80MW, the turbine enters the following mode, at this time, the bypass enters the backup mode, finally, the gas turbine load is increased to the total load of 402MW, and the coordination and AGC control is put into operation.

2. The APS adaptive start-stop control method of claim 1, wherein, In S102, when the temperature difference between the upper and lower wall temperatures of the boiler high-pressure drum exceeds 30℃, the boiler protection mechanism is triggered, the bypass is slowly opened to full opening, the boiler side starting exhaust is kept fully open under the condition that the wall temperature continues to increase, participates in pressure control, and when the upper and lower wall temperatures fall to normal, the bypass is cut to control the rush parameter, and the starting exhaust is fully closed.

3. The APS adaptive start-stop control method of claim 2, wherein, In the boiler protection mechanism, the gas turbine is closed for load increase and the drain system.

4. The APS adaptive start-stop control method of claim 3, wherein, In the medium pressure and steam process, the medium pressure superheater starts the full-automatic control of exhaust, keeps open before failing to combine steam, ensures the medium pressure drum to have certain flow, and closes after combining steam.

5. The APS adaptive start-stop control method of claim 1, wherein, The starting step sequence includes 5 breakpoints, and the 5 breakpoints are respectively: Breakpoint 1, system preparation breakpoint, the breakpoint 1 includes 5 sub-function groups, and the breakpoint 1 breakpoint completion condition includes: 1a-closed water system startup completion; 1b-open water system startup completion; 1c-circulating water system startup completion; 1d-lubricating oil system startup completion; 1e-EH oil system startup completion; Breakpoint 2, waste heat boiler water filling breakpoint, the breakpoint 2 includes 7 sub-function groups, and the breakpoint 2 completion condition includes: 2a-condensate water system startup completion; 2b- auxiliary steam system has been put into operation; 2c-low pressure drum water level meets the startup requirement; 2d-medium pressure drum water level meets the startup requirement; 2e-high pressure drum water level meets the startup requirement; 2f-shaft seal system has been put into operation; 2g-vacuum system has been put into operation; Breakpoint 3, gas turbine startup and grid connection breakpoint, the breakpoint 3 includes 5 sub-function groups, and the breakpoint 3 completion condition includes: 3a-gas turbine runs and carries initial load, 3b-turbine rotation parameter meets the requirement, 3c-bypass automatic state and setting value automatic follow-up; Breakpoint 4, turbine rotation and grid connection breakpoint, the breakpoint 4 includes 3 sub-function groups, and the breakpoint 4 completion condition includes: 4a-turbine 3000 rpm and carries initial load; Breakpoint 5, load increase breakpoint, the breakpoint 5 includes 3 sub-function groups, and the breakpoint 5 completion condition includes: 5a-high pressure / medium pressure / low pressure control has been put into operation, and pressure automatic setting value has been given; 5b-CCS has been put into operation; 5c-auxiliary steam source switching is completed; 5d-unit level APS startup process breakpoint setting; The shutdown step sequence includes 3 breakpoints, and the 3 breakpoints are respectively: Breakpoint 6, load reduction breakpoint, the breakpoint 6 is provided with 4 sub-function groups, and the breakpoint 6 completion condition includes 6a-AGC, primary frequency modulation and CCS mode exit; 6b-gas turbine is reduced to shutdown load; 6c-auxiliary steam source switching is completed; Breakpoint 7, turbine de-parallel connection breakpoint, the breakpoint 7 is provided with 2 sub-function groups, and the breakpoint 7 completion condition includes: 7a-turbine load is less than 15 MW; 7b-hanging brake signal disappears; Breakpoint 8, gas turbine de-parallel connection breakpoint, the breakpoint 8 is provided with 4 sub-function groups, and the breakpoint 8 completion condition includes: 8a-high, medium pressure feed water pump full stop; 8b-waste heat boiler shutdown water level; Breakpoint 9, unit shutdown breakpoint, the breakpoint 9 is provided with 3 sub-function groups, and the breakpoint 9 completion condition includes: 9a-vacuum and shaft seal system; 9b-condensate water pump full stop.

6. The APS adaptive start-stop control method of claim 5, wherein, The starting step sequence is as follows: Q101, start the closed cooling water system subprogram group, make the closed cooling water system run, and delay for 60s; Q102, start the air compressor program control to make the compressed air normal; Q103, start the circulating water system subprogram group, make the circulating water system run, and delay for 60s; Q104, manually confirm that water injection and emptying are completed; Q105, start the open circulating water subprogram group, make the open circulating water system run, and delay for 60s; Q106, Unit start-up preparation completion breakpoint; Q107, Start-up turbine auxiliary system, let turbine auxiliary system in start-up, delay 60s; Q108, Start-up condensate water system subprogram group, let condensate water system run, delay 60s; Q109, Auxiliary steam system normal, put shaft seal, shaft seal system normal, DEH allows vacuum extraction signal; Q110, Start-up vacuum extraction system, let vacuum extraction system normal, delay 60s; Q111, Start-up condensate water heater system subprogram group, let condensate water heater system has run, delay 60s; Q112, Start-up low-pressure steam drum feedwater system subprogram group, let low-pressure steam drum feedwater system subprogram group has run; Q113, Low-pressure steam drum reaches start-up water level SP1; Q114, Start-up medium-pressure steam drum feedwater system subprogram group to has run; Q115, Medium-pressure steam drum reaches start-up water level SP1 or waste heat boiler is running; Q116, Start-up high-pressure steam drum feedwater system subprogram group to has run; Q117, High-pressure steam drum reaches start-up water level SP1 or waste heat boiler is running; Q118, Turbine auxiliary system start-up completion, steam turbine preparation start-up confirmation; Q119, Start-up steam turbine system, let steam turbine system in start-up; Q120, Open waste heat boiler outlet flue gas damper, let waste heat boiler outlet flue gas damper has opened; gas turbine preparation ready signal; gas turbine preparation start-up confirmation; Q121, Start-up gas turbine system, let gas turbine system in start-up; Q122, Start-up low-pressure steam system subprogram group to has started; Q123, Start-up medium-pressure steam system subprogram group to has started; Q124, Start-up high-pressure steam system subprogram group to has started; Q125, Gas turbine generator has been grid-connected; Q126, Steam turbine generator has been grid-connected; Q127, Load increase confirmation; Q128, Put coordination; Q129, Send target load to gas turbine, unit total load reaches target load; Q130, Combined cycle start-up completion.

7. The APS adaptive start-stop control method of claim 6, wherein, The stop sequence is as follows: T201, Send AGC exit instruction and let AGC has exited; T202, Gas turbine load reduction to AGC lower limit value; T203, Unit primary frequency modulation has exited; CCS has exited; T204, Auxiliary steam source switching to has completed; T205, Gas turbine load reduction to stop load; T206, Start-up steam turbine stop program control TCS; high-pressure control, medium-pressure control have exited; steam turbine load < 15MW; hang-up signal loss; turning gear has been put into; Steam turbine stop program control has been completed; T207, Start-up gas turbine stop program control TCS to has completed; gas turbine has been extinguished; T208, Stop waste heat boiler high, medium, and low-pressure feedwater systems to has stopped running; each steam bypass has been closed for 15min; T210, Stop condensate water heater system to has stopped running; T211, Start-up vacuum system stop program control to completion; T212, Start-up turbine auxiliary system stop program control to completion; T213, Stop condensate water system to has stopped running; T215, Waste heat boiler outlet flue gas damper has been closed; T216, APS stop sequence completion.