Gas-steam combined cycle unit starting method and system

Abstract

The invention provides a gas-steam combined cycle unit starting method and system. The method comprises the steps that starting conditions of a gas-steam combined cycle unit are determined; under the condition that the gas-steam combined cycle unit meets the starting condition, auxiliary equipment needing to be started is pre-selected, and grid connection is conducted after a gas turbine is controlled to be started; starting the steam turbine and controlling the steam turbine to run until grid connection; controlling the gas-steam combined cycle unit to rise to full load; and when feedback signals that the gas turbine is loaded and is put into use for steam extraction and heat supply are received, starting of the gas-steam combined cycle unit is completed. According to the method, breakpoint setting of the APS system of the combined cycle unit is simplified, unnecessary steps and condition judgment are reduced, the response speed and operation efficiency of the APS system are effectively improved, the problems that due to unreasonable breakpoint design, operation of the APS system is unstable, operation complexity is increased and the like are solved, and the starting process of the unit is more efficient and reliable.

Description

Technical Field

[0001] The present invention belongs to the technical field of power unit automation control, and in particular relates to a gas-steam combined cycle unit starting method and system. Background Art

[0002] With the power industry's growing demand for efficient and clean power generation technologies, gas-steam combined cycle units, owing to their high energy efficiency and low emissions, have become a core component of power generation. Their startup process involves the coordinated operation of multiple systems, including the gas turbine, steam turbine, and waste heat boiler, placing extremely high demands on automated control technology. Existing automatic powerplant startup and shutdown systems (APS) achieve a certain degree of automation.

[0003] CN104062960A discloses an automatic start controller, a power plant automatic start control system and a control method thereof. The proposed automatic start controller adopts a "unit level-functional group level-sub-group level" hierarchical control architecture, which divides the start-up of the gas turbine, waste heat boiler and steam turbine into independent submodules (such as the gas turbine start submodule with 7 breakpoints and the steam turbine start submodule with 6 breakpoints), and relies on manual confirmation of the breakpoint transition (such as the waste heat boiler start process needs to be manually triggered after the gas turbine is connected to the grid). This design leads to data interaction lags between heterogeneous systems (such as the gas turbine TCS and the steam turbine DEH), low cross-system collaboration efficiency, and inability to achieve seamless integrated control of the entire process. In particular, manual intervention is still required in key links such as gas turbine automatic ignition and load dynamic adjustment, making it difficult to meet the rapid response requirements under complex working conditions. The gas power station start-up and shutdown method disclosed in CN115437329A divides the startup process into five functional groups. Each functional group requires manual confirmation of the completion signal (for example, the preparation functional group needs to start eight subsystems in sequence and manually confirm them). The number of breakpoints is large and the condition judgment is redundant, resulting in a lengthy startup process. The risk of operational errors increases synchronously with the complexity of the breakpoints, making it difficult to achieve a balance between efficiency and safety. Summary of the Invention

[0004] The present invention provides a gas-steam combined cycle unit startup method and system to solve the problems in the prior art that it is difficult to meet the rapid response requirements under complex working conditions, the risk of operational errors increases synchronously with the complexity of breakpoints, and it is difficult to achieve a balance between efficiency and safety.

[0005] In a first aspect, the present invention provides a method for starting a gas-steam combined cycle unit, comprising:

[0006] Determine the startup conditions of gas-steam combined cycle units;

[0007] When the gas-steam combined cycle unit meets the startup conditions, pre-select the auxiliary equipment that needs to be started and control the gas turbine to start and connect to the grid;

[0008] Start the steam turbine and control the turbine to run until it is connected to the grid;

[0009] Control the gas-steam combined cycle unit to full load; when the feedback signal of the gas turbine being loaded and the extraction steam being used for heating is received, it indicates that the gas-steam combined cycle unit has been started.

[0010] Optionally, determining the startup conditions of the gas-steam combined cycle unit includes:

[0011] Confirm that the engine side meets the start-up conditions and the load limit mode and automatic load limit exit;

[0012] Make sure there is no trip signal on the turbine side, the internal cylinder temperature difference is within the allowable range, and the condenser water level is normal;

[0013] Make sure that the feedwater heater, low-pressure steam drum and high-pressure economizer water inlet electric isolation doors on the waste heat boiler side are in the open position.

[0014] Optionally, when the gas-steam combined cycle unit meets the startup conditions, preselecting auxiliary equipment that needs to be started and controlling the gas turbine to be connected to the grid after startup includes:

[0015] When the engine ignition signal is detected, the engine ignition speed is controlled and the pre-selected deaeration recirculation pump and pre-selected gas heating pump are started at the same time, and the high-pressure bypass, low-pressure bypass and high-pressure main steam are put into use for heating;

[0016] When the engine speed rises to the first speed, the TCA blower, the preselected high-pressure water pump and the preselected low-pressure feed pump are started simultaneously;

[0017] When the engine speed rises to the second speed, the grid connection instruction is determined. After the engine is successfully connected to the grid, the engine load is increased to different fixed values according to the turbine start-up mode preselected in the preselection stage.

[0018] Optionally, starting the steam turbine and controlling the steam turbine to start up until grid connection includes:

[0019] Before starting the steam turbine, ensure that vacuum protection, shaft seal cooling water, lubricating oil temperature control, and turbine lock are activated;

[0020] When the turbine meets the start-up conditions, the corresponding speed and acceleration rate are set according to the turbine start-up mode preselected in the preselection stage to perform the start-up operation;

[0021] When the speed reaches the preset speed, warm-up is determined and the speed is increased to the third speed within the preset time;

[0022] When the turbine speed exceeds the third speed, the turbine grid connection instruction is determined;

[0023] After the steam turbine is connected to the grid, make sure to fully open the high-pressure regulating valve, close the high-pressure bypass, and stop the main steam heating.

[0024] Optionally, controlling the gas-steam combined cycle unit to reach full load includes:

[0025] When the steam turbine load reaches a first constant value, the gas turbine load increase rate is determined to bring the gas turbine to full load;

[0026] When the low-pressure superheated steam temperature, low-pressure main steam pressure and turbine load reach the second set value, determine to fully open the low-pressure main steam valve and start the low-pressure throttle control. After the low-pressure throttle is fully opened, set the low-pressure bypass pressure value.

[0027] When the steam turbine load exceeds the third set value, gradually open the drain valve and electric door, start the extraction quick-closing solenoid valve and adjust the opening to control the extraction pressure until the extraction port pressure meets the conditions and then fully open the quick-closing valve to complete the extraction steam heating.

[0028] In a second aspect, the present invention provides a gas-steam combined cycle unit startup system, comprising:

[0029] A determination module, used to determine the start-up conditions of the gas-steam combined cycle unit;

[0030] The gas turbine grid connection module is used to pre-select the auxiliary equipment that needs to be started and control the grid connection after the gas turbine is started when the gas-steam combined cycle unit meets the startup conditions;

[0031] The steam turbine grid connection module is used to start the steam turbine and control the turbine's run-up until it is connected to the grid;

[0032] The unit load increase module is used to control the gas-steam combined cycle unit to reach full load; when the feedback signal of the gas turbine carrying load and using extraction steam for heating is received, it indicates that the gas-steam combined cycle unit has been started.

[0033] Optionally, the determining module includes:

[0034] The first determining unit is used to determine whether the combustion engine side meets the startup conditions and the load limit mode and the automatic load limit exit;

[0035] The second determination unit is used to determine that there is no trip signal on the turbine side, the internal cylinder temperature difference is within the allowable range, and the condenser water level is normal;

[0036] The third determining unit is used to determine whether the feedwater heater, the low-pressure steam drum and the high-pressure economizer water inlet electric isolation door on the waste heat boiler side are in the open position.

[0037] Optionally, the gas turbine grid-connected module includes:

[0038] The fourth determining unit is used to determine and control the ignition speed increase of the gas engine when the gas engine ignition signal is detected, and simultaneously start the preselected deaeration recirculation pump and the preselected gas heating pump, and put the high-pressure bypass, low-pressure bypass and high-pressure main steam into use for heating;

[0039] a fifth determining unit, configured to determine to simultaneously start the TCA blower, the preselected high-pressure water pump, and the preselected low-pressure feed pump when the speed of the combustion engine rises to the first speed;

[0040] The sixth determining unit is used to determine the grid connection instruction when the gas turbine speed rises to the second speed. After the gas turbine is successfully connected to the grid, the gas turbine load is increased to different fixed values according to the steam turbine starting mode preselected in the preselection stage.

[0041] Optionally, the steam turbine grid connection module includes:

[0042] The seventh determination unit is used to determine whether to put vacuum protection, shaft seal cooling water, lubricating oil temperature control and turbine lock before the turbine is started;

[0043] The start-up setting unit is used to set the corresponding speed and acceleration rate according to the steam turbine starting mode preselected in the preselection stage when the steam turbine meets the start-up conditions, so as to perform the start-up operation;

[0044] an eighth determining unit, configured to determine to perform warm-up when the speed reaches a preset speed, and to increase the speed to a third speed within a preset time;

[0045] A ninth determining unit is configured to determine a steam turbine grid connection instruction when the steam turbine speed exceeds a third speed;

[0046] The tenth determination unit is used to determine whether to fully open the high-pressure regulating valve, close the high-pressure bypass, and stop the main steam heating after the steam turbine is connected to the grid.

[0047] Optionally, the unit load increasing module includes:

[0048] an eleventh determining unit, configured to determine and set a gas turbine load increase rate to bring the gas turbine to full load when the steam turbine load reaches a first set value;

[0049] a twelfth determining unit, for determining to fully open the low-pressure main steam valve and to activate the low-pressure regulating valve control when the low-pressure superheated steam temperature, the low-pressure main steam pressure, and the turbine load reach a second set value; and setting the low-pressure bypass pressure value after the low-pressure regulating valve is fully opened;

[0050] The thirteenth determination unit is used to determine the gradual opening of the drain valve and the electric door, the activation of the exhaust gas quick-closing solenoid valve and adjust the opening, and the control of the exhaust gas pressure when the steam turbine load exceeds the third set value, until the exhaust gas port pressure meets the conditions and the quick-closing valve is fully opened to complete the activation of the exhaust gas heating.

[0051] The present invention provides a method and system for starting a gas-steam combined cycle unit, wherein the method includes determining, preselecting, and multi-stage controlling the starting conditions of the combined cycle unit, so as to optimize the breakpoint design and reduce redundant steps. The present invention can select the starting mode according to the unit status, and control the processes such as gas turbine ignition, grid connection, load increase, and steam turbine impulse connection. Optimization is performed on the breakpoint design, which simplifies the breakpoint setting of the APS system of the combined cycle unit, reduces unnecessary steps and condition judgments, and effectively improves the response speed and operating efficiency of the APS system. While ensuring the safe operation of the unit, the simplicity of operation and the flexibility of the APS system are fully considered, avoiding problems such as unstable operation of the APS system and increased operational complexity due to unreasonable breakpoint design, making the startup process of the unit more efficient and reliable. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] In order to more clearly illustrate the technical solution of the present invention, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are merely embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0053] Figure 1 A schematic flow chart of a method for starting a gas-steam combined cycle unit provided in an embodiment of the present invention;

[0054] Figure 2 APS modular system structure design diagram provided for an embodiment of the present invention;

[0055] Figure 3 A schematic structural diagram of a gas-steam combined cycle unit startup system provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0056] The following will provide a clear and complete description of the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0057] Example 1

[0058] like Figure 1 and Figure 2As shown, an embodiment of the present invention provides a method for starting a gas-steam combined cycle unit, comprising:

[0059] Step 101: Determine the startup conditions of the gas-steam combined cycle unit.

[0060] Before starting the APS of a gas-steam combined cycle unit (referred to as the combined cycle unit in this embodiment), it is necessary to determine the starting conditions, including:

[0061] Determine whether the combustion engine (gas turbine) meets the startup conditions and whether the load limit mode and ALR (automatic load limit) are exited.

[0062] Make sure there is no trip signal on the turbine side, the internal cylinder temperature difference is within the allowable range, and the condenser water level is normal.

[0063] Make sure that the feedwater heater, low-pressure steam drum and high-pressure economizer water inlet electric isolation doors on the waste heat boiler side are in the open position.

[0064] The conditions on the gas turbine side, steam turbine side, and waste heat boiler side must be met at the same time. If they are not met at the same time, the process ends or returns to the waiting state.

[0065] Step 102: When the gas-steam combined cycle unit meets the startup conditions, preselect the auxiliary equipment that needs to be started and control the gas turbine to start and then connect to the grid.

[0066] In this step, the preselected auxiliary equipment includes but is not limited to a high-pressure feed pump, a low-pressure feed pump, a gas heating pump and a deaeration recirculation pump; the start-up mode is preselected according to the actual state of the steam turbine (cold, warm and hot).

[0067] In this step, three control stages are designed based on the characteristics and operating procedures of the combined cycle unit. In each control stage, the relevant sub-program control model is called and breakpoints are set where necessary:

[0068] After receiving the APS system start-up command, the gas turbine is started. When the gas turbine speed rises to the first speed (for example, 10 rpm), the following sub-program control modules are called at the same time: the TCA blower is started to ensure that the temperature of the gas turbine is effectively controlled during startup and operation; the pre-selected high-pressure water pump and the pre-selected low-pressure feed pump are started to ensure the normal operation of the unit's water circulation system.

[0069] After the gas turbine ignition signal is detected, the gas turbine ignition speed is determined, and the following sub-program control modules are called at the same time: the pre-selected deaeration recirculation pump and the pre-selected gas heating pump are started, and the high bypass (high pressure bypass), low bypass (low pressure bypass) and high-pressure main steam heating are put into use to ensure that the gas turbine can smoothly transition to a stable operating state after ignition.

[0070] When the engine speed rises to the second speed (for example, 3000rpm), the grid connection instruction is determined. When the engine generator voltage increases to the grid connection parameter, a "engine manual grid connection permission signal" is issued. At this time, the operator needs to manually input the grid connection instruction (i.e., the first breakpoint). After the engine is successfully connected to the grid, the engine load is increased to different fixed values according to the turbine start-up mode (cold, warm, and hot) preselected in the preselection stage.

[0071] Take the M701DA combined cycle unit as an example: when pre-selecting cold start, the gas turbine load is set to 17MW; when pre-selecting warm start, the gas turbine load is set to 50MW, and when the gas turbine exhaust temperature is greater than the upper wall temperature of the high-pressure inner cylinder of the steam turbine by 80°C, the load increase is stopped (the maximum load of the gas turbine does not exceed 50MW); when pre-selecting hot start, the gas turbine load is set to 65MW, and when the gas turbine exhaust temperature is greater than the upper wall temperature of the high-pressure inner cylinder of the steam turbine by 60°C, the load increase is stopped (the maximum load of the gas turbine does not exceed 65MW).

[0072] Step 103: Start the steam turbine and control the turbine to start up until it is connected to the grid.

[0073] Before the steam turbine is started, vacuum protection, shaft seal cooling water and lubricating oil temperature control are automatically activated, and then the steam turbine is shut down.

[0074] When the turbine start-up conditions are met, a "manual start-up permission signal" is issued, requiring the operator to manually perform the start-up operation (i.e., the second breakpoint). During the start-up process, the corresponding target speed and acceleration rate are set according to Table 1 based on the turbine start-up mode (cold, warm, and hot) preselected in the preselection stage. After the speed reaches the preset speed, the turbine is warmed up and increased to the third speed (e.g., 3000 r / min) within a preset time. After the speed reaches the preset speed, the turbine is automatically stopped and cranked.

[0075] Table 1 Speed and acceleration rate corresponding to turbine starting mode

[0076] Control parameters Cold start Warm start Hot start Target speed (r / min) 1350 (warm-up) → 3000 1350 (warm-up) → 3000 Direct 3000 (no warm-up) Increase rate (r / min) 100 150 200 Warm-up time (min) 30 15 0 (skip warm-up)

[0077] When the turbine speed exceeds 3000r / min, that is, when the turbine generator automatically increases the voltage to the grid-connected parameter, a "steam turbine manual permission grid-connected signal" is issued. At this time, the operator needs to manually input the grid-connected instruction (that is, the third breakpoint).

[0078] After the steam turbine is connected to the grid, the following sub-program control modules are called simultaneously: the high-pressure regulating valve is fully opened to ensure that the steam turbine can adjust its output power according to the grid demand; the high-pressure bypass is closed to reduce the bypass flow of steam, improve the efficiency of the combined cycle unit, and ensure that all steam passes through the steam turbine to perform work; the main steam heating is disabled to optimize the operation of the combined cycle unit and save energy.

[0079] Step 104, controlling the gas-steam combined cycle unit to increase to full load; wherein, when a feedback signal indicating that the gas turbine is loaded and extraction steam is used for heating is received, it indicates that the gas-steam combined cycle unit has been started.

[0080] When the turbine load reaches the first set value, the turbine load ramp rate is set to bring the turbine to full load. When the turbine load reaches approximately 70%, desuperheating water control is initiated. During this process, temperature monitoring is continuously performed. When the turbine exhaust temperature exceeds the upper wall temperature of the high-pressure inner cylinder by 80°C, the load ramp is suspended and a flashing warning is issued.

[0081] When the low-pressure superheated steam temperature, low-pressure main steam pressure and turbine load reach the second set value, determine to fully open the low-pressure main steam valve and put the low-pressure regulating valve into control. After the low-pressure regulating valve is fully opened, set the low-pressure bypass pressure value.

[0082] When the steam turbine load exceeds the third set value, gradually open the drain valve and electric door, start the extraction quick-closing solenoid valve and adjust the opening to control the extraction pressure until the extraction port pressure meets the conditions and then fully open the quick-closing valve to complete the extraction steam heating.

[0083] In summary, this embodiment provides a method for starting a gas-steam combined cycle unit. By building an integrated control platform for the entire station and integrating various subsystems into a unified framework, this method effectively resolves compatibility issues and significantly improves the system's overall performance and operational ease. Furthermore, by addressing the functional limitations caused by the closed TCS system, improved design successfully enables operations such as gas turbine ignition, grid connection, and load ramping and reduction within the APS, significantly enhancing the system's integration and compatibility.

[0084] Fully automatic control from ignition to full load, full process automation and parameter optimization, based on the recognition of cold, warm and hot states of the combined cycle unit and matching of start-up modes, generates differentiated control strategies such as load increase rate and warm-up time, and only necessary manual confirmation nodes are set at the gas turbine grid connection (first breakpoint), steam turbine start-up (second breakpoint) and steam turbine grid connection (third breakpoint).

[0085] Optimizing breakpoint design simplifies breakpoint settings in the combined cycle unit APS system, reducing unnecessary steps and conditional judgments, and effectively improving the system's response speed and operational efficiency. Carefully designed breakpoints ensure safe unit operation while fully considering operational simplicity and system flexibility. This avoids problems such as system instability and increased operational complexity caused by improper design, making the combined cycle unit startup process more efficient and reliable.

[0086] Example 2

[0087] Based on the same inventive concept as Example 1, this embodiment also provides a gas-steam combined cycle unit startup system. Since the principle of solving the problem by this system is similar to the aforementioned gas-steam combined cycle unit startup method, the implementation of this system can refer to the implementation of the gas-steam combined cycle unit startup method.

[0088] like Figure 3 As shown in the figure, the gas-steam combined cycle unit startup system includes:

[0089] The determination module 10 is used to determine the start-up conditions of the gas-steam combined cycle unit.

[0090] The gas turbine grid connection module 20 is used to preselect auxiliary equipment that needs to be started and control the gas turbine to be connected to the grid after starting when the gas-steam combined cycle unit meets the starting conditions.

[0091] The steam turbine grid connection module 30 is used to start the steam turbine and control the steam turbine to start up until it is connected to the grid.

[0092] The unit load increase module 40 is used to control the gas-steam combined cycle unit to reach full load; when the feedback signal of the gas engine carrying load and using extraction steam for heating is received, it indicates that the gas-steam combined cycle unit is started up.

[0093] Exemplarily, the determining module includes:

[0094] The first determining unit is configured to determine whether the combustion engine side meets the startup conditions and whether the load limiting mode and the automatic load limiting mode are exited.

[0095] The second determining unit is used to determine that there is no trip signal on the turbine side, the internal cylinder temperature difference is within an allowable range, and the condenser water level is normal.

[0096] The third determining unit is used to determine whether the feedwater heater, the low-pressure steam drum and the high-pressure economizer water inlet electric isolation door on the waste heat boiler side are in the open position.

[0097] Exemplarily, the gas turbine grid connection module includes:

[0098] The fourth determination unit is used to determine and control the engine ignition speed increase when the engine ignition signal is detected, and simultaneously start the preselected deaeration recirculation pump and the preselected gas heating pump, and put the high-pressure bypass, low-pressure bypass and high-pressure main steam into use for heating.

[0099] The fifth determining unit is used to determine to start the TCA blower, the preselected high-pressure water pump and the preselected low-pressure feed pump simultaneously when the speed of the combustion engine rises to the first speed.

[0100] The sixth determining unit is used to determine the grid connection instruction when the gas turbine speed rises to the second speed. After the gas turbine is successfully connected to the grid, the gas turbine load is increased to different fixed values according to the steam turbine starting mode preselected in the preselection stage.

[0101] Exemplarily, the steam turbine grid connection module includes:

[0102] The seventh determination unit is used to determine the activation of vacuum protection, shaft seal cooling water, lubricating oil temperature control and turbine lock before the turbine is started.

[0103] The start-up setting unit is used to set the corresponding speed and acceleration rate according to the steam turbine starting mode preselected in the preselection stage when the steam turbine meets the start-up conditions to perform the start-up operation.

[0104] The eighth determining unit is configured to determine to perform warm-up when the speed reaches a preset speed, and to increase the speed to a third speed within a preset time.

[0105] The ninth determining unit is configured to determine a steam turbine grid connection instruction when the steam turbine speed exceeds a third speed.

[0106] The tenth determination unit is used to determine whether to fully open the high-pressure regulating valve, close the high-pressure bypass, and stop the main steam heating after the steam turbine is connected to the grid.

[0107] Exemplarily, the unit load increasing module includes:

[0108] The eleventh determining unit is used to determine and set the gas turbine load increase rate when the steam turbine load reaches the first constant value, so as to bring the gas turbine to full load.

[0109] The twelfth determination unit is used to determine the full opening of the low-pressure main steam valve and put the low-pressure regulating valve into control when the low-pressure superheated steam temperature, the low-pressure main steam pressure and the steam turbine load reach the second set value. After the low-pressure regulating valve is fully opened, the low-pressure bypass pressure value is set.

[0110] The thirteenth determination unit is used to determine the gradual opening of the drain valve and the electric door, the activation of the exhaust gas quick-closing solenoid valve and adjust the opening, and the control of the exhaust gas pressure when the steam turbine load exceeds the third set value, until the exhaust gas port pressure meets the conditions and the quick-closing valve is fully opened to complete the activation of the exhaust gas heating.

[0111] For more specific working processes of the above modules, please refer to the corresponding content disclosed in Example 1, which will not be repeated here.

[0112] Example 3

[0113] This embodiment provides a computer device, including a processor and a memory; wherein, when the processor executes the computer program stored in the memory, the steps of the gas-steam combined cycle unit startup method described in Example 1 are implemented.

[0114] For more specific details about the above method, please refer to the corresponding content disclosed in Example 1, which will not be repeated here.

[0115] Example 4

[0116] This embodiment provides a computer-readable storage medium for storing a computer program; when the computer program is executed by a processor, the steps of the gas-steam combined cycle unit startup method described in Example 1 are implemented.

[0117] For more specific details about the above method, please refer to the corresponding content disclosed in Example 1, which will not be repeated here.

[0118] Example 5

[0119] This embodiment provides a computer program product, including computer-executable instructions or a computer program. When the computer-executable instructions or the computer program are executed by a processor, the steps of the gas-steam combined cycle unit startup method described in Example 1 are implemented.

[0120] For more specific details about the above method, please refer to the corresponding content disclosed in Example 1, which will not be repeated here.

[0121] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from the other embodiments. References to the same or similar parts between the various embodiments will be sufficient. The systems, devices, storage media, and computer program products disclosed in the embodiments correspond to the methods disclosed in the embodiments, so their descriptions are relatively simplified. For relevant details, refer to the method descriptions.

[0122] Those skilled in the art will clearly understand that the techniques in the embodiments of the present invention can be implemented using software plus a necessary general-purpose hardware platform. Based on this understanding, the technical solutions in the embodiments of the present invention, or the portion that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a storage medium such as ROM / RAM, a magnetic disk, or an optical disk, and includes a number of instructions for enabling a computer device (which can be a personal computer, server, or network device, etc.) to execute the methods described in various embodiments of the present invention or certain portions of the embodiments.

[0123] In some embodiments, computer-executable instructions may be in the form of a program, software, software module, script, or code, written in any form of programming language (including compiled or interpreted languages, or declarative or procedural languages), and may be deployed in any form, including as a stand-alone program or as a module, component, subroutine, or other unit suitable for use in a computing environment.

[0124] As an example, computer-executable instructions may, but need not, correspond to a file in a file system, may be stored as part of a file that stores other programs or data, such as in one or more scripts in a HyperText Markup Language (HTML) document, in a single file dedicated to the program in question, or in multiple coordinating files (e.g., files storing one or more modules, subroutines, or code portions).

[0125] By way of example, computer-executable instructions may be deployed to be executed on one electronic device, or on multiple electronic devices located at one site, or on multiple electronic devices distributed across multiple sites and interconnected by a communication network.

[0126] The present invention has been described in detail above with reference to specific embodiments and exemplary examples. However, these descriptions should not be construed as limiting the present invention. Those skilled in the art will appreciate that various equivalent substitutions, modifications, or improvements may be made to the technical solutions and implementations of the present invention without departing from the spirit and scope of the present invention, all of which fall within the scope of the present invention. The scope of protection of the present invention shall be determined by the appended claims.

Claims

1. A method for starting a gas-steam combined cycle unit, characterized in that: include: Determine the startup conditions of gas-steam combined cycle units; When the gas-steam combined cycle unit meets the startup conditions, pre-select the auxiliary equipment that needs to be started and control the gas turbine to start and connect to the grid; Start the steam turbine and control the turbine to run until it is connected to the grid; Control the gas-steam combined cycle unit to full load; when the feedback signal of the gas turbine being loaded and the extraction steam being used for heating is received, it indicates that the gas-steam combined cycle unit has been started.

2. The method for starting a gas-steam combined cycle unit according to claim 1, characterized in that: Determining the startup conditions of the gas-steam combined cycle unit includes: Confirm that the engine side meets the start-up conditions and the load limit mode and automatic load limit exit; Make sure there is no trip signal on the turbine side, the internal cylinder temperature difference is within the allowable range, and the condenser water level is normal; Make sure that the feedwater heater, low-pressure steam drum and high-pressure economizer water inlet electric isolation doors on the waste heat boiler side are in the open position.

3. The method for starting a gas-steam combined cycle unit according to claim 1, characterized in that: When the gas-steam combined cycle unit meets the startup conditions, preselecting auxiliary equipment that needs to be started and controlling the gas turbine to start and then connect to the grid includes: When the engine ignition signal is detected, the engine ignition speed is controlled and the pre-selected deaeration recirculation pump and pre-selected gas heating pump are started at the same time, and the high-pressure bypass, low-pressure bypass and high-pressure main steam are put into use for heating; When the engine speed rises to the first speed, the TCA blower, the preselected high-pressure water pump and the preselected low-pressure feed pump are started simultaneously; When the engine speed rises to the second speed, the grid connection instruction is determined. After the engine is successfully connected to the grid, the engine load is increased to different fixed values according to the turbine start-up mode preselected in the preselection stage.

4. The method for starting a gas-steam combined cycle unit according to claim 1, characterized in that: The starting of the steam turbine and controlling the turbine to run immediately until the turbine is connected to the grid includes: Before starting the steam turbine, ensure that vacuum protection, shaft seal cooling water, lubricating oil temperature control, and turbine lock are activated; When the turbine meets the start-up conditions, the corresponding speed and acceleration rate are set according to the turbine start-up mode preselected in the preselection stage to perform the start-up operation; When the speed reaches the preset speed, warm-up is determined and the speed is increased to the third speed within the preset time; When the turbine speed exceeds the third speed, the turbine grid connection instruction is determined; After the steam turbine is connected to the grid, make sure to fully open the high-pressure regulating valve, close the high-pressure bypass, and stop the main steam heating.

5. The gas-steam combined cycle unit startup method according to claim 1, characterized in that: The controlling the gas-steam combined cycle unit to reach full load comprises: When the steam turbine load reaches a first constant value, the gas turbine load increase rate is determined to bring the gas turbine to full load; When the low-pressure superheated steam temperature, low-pressure main steam pressure and turbine load reach the second set value, determine to fully open the low-pressure main steam valve and start the low-pressure throttle control. After the low-pressure throttle is fully opened, set the low-pressure bypass pressure value. When the steam turbine load exceeds the third set value, gradually open the drain valve and electric door, start the extraction quick-closing solenoid valve and adjust the opening to control the extraction pressure until the extraction port pressure meets the conditions and then fully open the quick-closing valve to complete the extraction heating.

6. A gas-steam combined cycle unit startup system, characterized in that: include: A determination module, used to determine the start-up conditions of the gas-steam combined cycle unit; The gas turbine grid connection module is used to pre-select the auxiliary equipment that needs to be started and control the grid connection after the gas turbine is started when the gas-steam combined cycle unit meets the startup conditions; The steam turbine grid connection module is used to start the steam turbine and control the turbine's run-up until it is connected to the grid; The unit load increase module is used to control the gas-steam combined cycle unit to reach full load; when the feedback signal of the gas turbine carrying load and using extraction steam for heating is received, it indicates that the gas-steam combined cycle unit has been started.

7. The gas-steam combined cycle unit startup system according to claim 6, characterized in that: The determination module includes: The first determining unit is used to determine whether the combustion engine side meets the startup conditions and the load limit mode and the automatic load limit exit; The second determination unit is used to determine that there is no trip signal on the turbine side, the internal cylinder temperature difference is within the allowable range, and the condenser water level is normal; The third determining unit is used to determine whether the feedwater heater, the low-pressure steam drum and the high-pressure economizer water inlet electric isolation door on the waste heat boiler side are in the open position.

8. The gas-steam combined cycle unit startup system according to claim 6, characterized in that: The gas turbine grid connection module includes: The fourth determining unit is used to determine and control the ignition speed increase of the gas engine when the gas engine ignition signal is detected, and simultaneously start the preselected deaeration recirculation pump and the preselected gas heating pump, and put the high-pressure bypass, low-pressure bypass and high-pressure main steam into use for heating; a fifth determining unit, configured to determine to simultaneously start the TCA blower, the preselected high-pressure water pump, and the preselected low-pressure feed pump when the speed of the combustion engine rises to the first speed; The sixth determining unit is used to determine the grid connection instruction when the gas turbine speed rises to the second speed. After the gas turbine is successfully connected to the grid, the gas turbine load is increased to different fixed values according to the steam turbine starting mode preselected in the preselection stage.

9. The gas-steam combined cycle unit startup system according to claim 6, characterized in that: The steam turbine grid connection module includes: The seventh determination unit is used to determine whether to put vacuum protection, shaft seal cooling water, lubricating oil temperature control and turbine lock before the turbine is started; The start-up setting unit is used to set the corresponding speed and acceleration rate according to the steam turbine starting mode preselected in the preselection stage when the steam turbine meets the start-up conditions, so as to perform the start-up operation; an eighth determining unit, configured to determine to perform warm-up when the speed reaches a preset speed, and to increase the speed to a third speed within a preset time; A ninth determining unit is configured to determine a steam turbine grid connection instruction when the steam turbine speed exceeds a third speed; The tenth determination unit is used to determine whether to fully open the high-pressure regulating valve, close the high-pressure bypass, and stop the main steam heating after the steam turbine is connected to the grid.

10. The gas-steam combined cycle unit startup system according to claim 6, characterized in that: The unit load increasing module includes: an eleventh determining unit, configured to determine and set a gas turbine load increase rate to bring the gas turbine to full load when the steam turbine load reaches a first set value; a twelfth determining unit, for determining to fully open the low-pressure main steam valve and to activate the low-pressure regulating valve control when the low-pressure superheated steam temperature, the low-pressure main steam pressure, and the turbine load reach a second set value; and setting the low-pressure bypass pressure value after the low-pressure regulating valve is fully opened; The thirteenth determination unit is used to determine the gradual opening of the drain valve and the electric door, the activation of the exhaust gas quick-closing solenoid valve and adjust the opening, and the control of the exhaust gas pressure when the steam turbine load exceeds the third set value, until the exhaust gas port pressure meets the conditions and the quick-closing valve is fully opened to complete the activation of the exhaust gas heating.

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