Method and device for starting unit without standby steam source

Abstract

The invention provides a unit starting method and device without a standby steam source, a steam conveying pipeline is arranged between a boiler superheater and a fuel oil atomization system of a unit, a bypass steam supply pipeline is arranged between a main steam pipeline and a shaft seal steam supply system, and the method comprises the steps that a mechanical atomization oil gun is adopted for boiler ignition, and the steam conveying pipeline is started; when the pressure of main steam in the steam conveying pipeline reaches first set pressure, the pressure and temperature of the steam conveyed to the fuel oil atomization oil gun are adjusted to range required by atomization, and the steam atomization oil gun is switched to operate; when the main steam pressure or the main steam temperature does not meet the shaft seal steam supply requirement, steam is supplied to a steam turbine shaft seal system through a bypass steam supply pipeline, and the shaft seal steam supply pressure is adjusted to the range needed by shaft seal sealing; when the main steam temperature and the main steam pressure both meet the shaft seal steam supply requirement, the main steam pipeline is switched to supply steam to the shaft seal system, and the vacuumizing system is started; and steam turbine running, grid connection and load lifting operations are carried out.

Description

Technical Field

[0001] This invention relates to the field of thermal power generator start-up control technology, and in particular to a method and apparatus for starting a generator unit without a backup steam source. Background Technology

[0002] During the startup process of traditional thermal power generating units, steam supply for shaft seals, fuel atomization, and system warm-up is typically provided by a startup boiler or an external auxiliary steam source. For units equipped with a startup boiler, auxiliary steam can be generated independently before the main steam is established, ensuring startup safety; for units connected to an external steam source, cold startup can also be achieved through external steam supply.

[0003] However, in scenarios without a start-up boiler and no external steam source, the unit lacks a stable auxiliary steam source, leading to problems such as inability to supply steam to the shaft seals, poor fuel atomization, and slow vacuum establishment, severely restricting the unit's autonomous start-up capability. Currently, although some power plants have attempted to address these issues by directly supplying main steam to the shaft seals or using superheater steam for temporary fuel atomization, these methods suffer from drawbacks such as inefficient control, large fluctuations in steam supply parameters, and conflicts in steam usage across multiple systems. Especially in the initial startup phase, when the main steam pressure and temperature are not yet stable, blindly supplying steam can easily cause thermal shock to the shaft seals or unstable combustion. Summary of the Invention

[0004] This invention provides a method and apparatus for starting a generator unit without a backup steam source, in order to solve the technical problems of insufficient steam supply to shaft seals and unstable fuel atomization in thermal power generator units due to the lack of an auxiliary steam source in the prior art.

[0005] On one hand, the present invention provides a method for starting up a unit without a backup steam source. A steam delivery pipeline is provided between the boiler superheater and the fuel oil atomization system of the unit, and a bypass steam supply pipeline is provided between the main steam pipeline and the shaft seal steam supply system. The method includes:

[0006] The boiler is ignited using a mechanical atomizing oil gun, and the steam delivery pipeline is opened.

[0007] When the main steam pressure in the steam delivery pipeline reaches the first set pressure, the steam pressure and temperature delivered to the fuel atomizing gun are adjusted to the range required for atomization, and the operation of the steam atomizing gun is switched.

[0008] When the main steam pressure or main steam temperature does not meet the requirements for shaft seal steam supply, steam is supplied to the turbine shaft seal system through the bypass steam supply pipeline, and the shaft seal steam supply pressure is adjusted to the range required for shaft seal sealing.

[0009] When the main steam temperature and main steam pressure both meet the requirements for shaft seal steam supply, switch to supplying steam to the shaft seal system from the main steam pipeline and start the vacuum system;

[0010] The turbine is started up, connected to the grid, and the load is increased to achieve unit startup.

[0011] According to the present invention, a method for starting a generator unit without a backup steam source includes performing turbine start-up, grid connection, and load increase operations to achieve unit startup, comprising:

[0012] The turbine bypass system is activated to raise the parameters of the main steam and reheat steam to the conditions required for turbine start-up.

[0013] Stop the turbine bypass system and start the turbine and connect it to the grid at a constant speed;

[0014] When the unit load reaches the set load, the auxiliary steam supply system is activated and the small steam turbine is started to complete the unit startup.

[0015] According to the present invention, a unit start-up method without a backup steam source is provided, wherein the steam delivery pipeline is connected between the soot blowing steam source pipeline at the outlet of the boiler superheater partition screen and the fuel atomizing steam pipeline.

[0016] According to the unit startup method without a backup steam source provided by the present invention, when supplying steam to the shaft sealing system through a bypass steam supply pipeline, the method further includes:

[0017] Real-time monitoring of the changing trend between shaft seal steam supply pressure and condenser vacuum build-up rate, and calculation of the dynamic correlation between the two within a preset time window;

[0018] When the dynamic correlation is lower than the set threshold and the vacuum build-up rate is consistently lower than the target rate, the steam flow rate of the bypass steam supply pipeline is automatically increased until the dynamic correlation returns to the normal range.

[0019] According to the unit startup method without a backup steam source provided by the present invention, after switching to steam atomizing oil gun operation, it further includes:

[0020] If an unstable combustion signal is detected, the decompression rate of the main steam to fuel atomization steam will be automatically reduced, and the parallel operation time of the mechanical atomization and steam atomization oil guns will be extended.

[0021] Once the combustion has stabilized, completely remove the mechanical atomizing oil gun.

[0022] According to the unit startup method without backup steam source provided by the present invention, before activating the turbine bypass system, the method further includes:

[0023] Determine whether the upward trend of the main steam pressure is continuous and without downward fluctuations;

[0024] If so, then the bypass system will be activated to accelerate the reheater's temperature rise;

[0025] If not, then suspend bypass operation, increase boiler combustion rate to a stable state, and then resume operation.

[0026] A unit startup method without a backup steam source provided by the present invention further includes:

[0027] Establish a priority coordination mechanism between fuel atomization steam demand and shaft seal steam supply demand.

[0028] According to the unit startup method without backup steam source provided by the present invention, a priority coordination mechanism is established between fuel atomization steam demand and shaft seal steam supply demand, including:

[0029] When the decrease in shaft seal steam pressure is detected to last for more than the first set time, or the shaft seal steam flow rate is lower than the minimum sealing flow rate, the regulating valve on the fuel atomizing steam branch is closed or throttled.

[0030] Available steam is preferentially distributed to the shaft seal steam supply system, and combustion stability is maintained by adjusting the combustion air ratio.

[0031] According to the unit start-up method without backup steam source provided by the present invention, a dual-source superposition transition method is adopted during the process of switching from bypass steam supply to main steam supply;

[0032] The dual-source superposition transition method includes:

[0033] First, maintain the bypass steam supply, then introduce the main steam supply;

[0034] After the main steam supply pressure stabilizes and remains stable for a preset time period, the bypass steam supply pipeline is then shut off to complete the switchover.

[0035] On the other hand, the present invention also provides a unit start-up device without a backup steam source, wherein a steam delivery pipeline is provided between the boiler superheater and the fuel oil atomization system of the unit, and a bypass steam supply pipeline is provided between the main steam pipeline and the shaft seal steam supply system, the device comprising:

[0036] The ignition and steam pre-ignition module uses a mechanical atomizing oil gun to ignite the boiler and open the steam delivery pipeline.

[0037] The fuel atomization switching module adjusts the steam pressure and temperature delivered to the fuel atomization gun to the required atomization range when the main steam pressure in the steam delivery pipeline reaches the first set pressure, and switches to operation of the steam atomization gun.

[0038] The shaft seal steam supply guarantee module supplies steam to the turbine shaft seal system through the bypass steam supply pipeline when the main steam pressure or main steam temperature does not meet the shaft seal steam supply requirements, and adjusts the shaft seal steam supply pressure to the range required for shaft seal sealing.

[0039] The shaft seal steam supply switching module switches to supply steam to the shaft seal system from the main steam pipeline and starts the vacuum system when both the main steam temperature and main steam pressure meet the requirements for shaft seal steam supply.

[0040] The unit grid connection control module performs turbine start-up, grid connection, and load increase operations to realize unit startup.

[0041] The unit startup method and apparatus without a backup steam source provided by this invention achieves autonomous startup of the unit under conditions without a backup steam source by setting up a steam delivery pipeline from the boiler superheater to the fuel oil atomization system and a bypass pipeline from the main steam to the shaft seal steam supply. This effectively solves the problems of insufficient shaft seal steam supply and lack of fuel oil atomization steam in the initial startup phase, significantly improves vacuum build-up speed and combustion stability, shortens startup time, and reduces dependence on external steam sources. Through a phased steam supply strategy and parameter feedback control, the steam demand of the two systems is effectively coordinated, avoiding steam resource conflicts between the systems. Attached Figure Description

[0042] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0043] Figure 1 This is a flowchart illustrating the unit startup method without a backup steam source provided in an embodiment of the present invention;

[0044] Figure 2 This is a schematic diagram of the structure of the unit starting device without backup steam source provided in an embodiment of the present invention;

[0045] Figure 3 This is a schematic diagram of the start-up steam for a 300MW subcritical unit without a backup steam source, provided in an embodiment of the present invention.

[0046] Figure 4 This is a schematic diagram of the structure of the electronic device provided in an embodiment of the present invention. Detailed Implementation

[0047] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0048] Figure 1This is a schematic flowchart of a unit startup method without a backup steam source provided in an embodiment of the present invention. In this invention, a steam delivery pipeline is provided between the boiler superheater and the fuel oil atomization system, and a bypass steam supply pipeline is provided between the main steam pipeline and the shaft seal steam supply system. A steam atomizing oil gun is pre-installed, eliminating the need for manual replacement after startup.

[0049] See Figure 1 The startup method for a generator unit without a backup steam source may include the following steps.

[0050] Step 101: Ignite the boiler using a mechanical atomizing oil gun and open the steam delivery pipeline.

[0051] In this step, the steam delivery pipeline refers to the dedicated pipeline connecting the boiler superheater outlet and the fuel atomization system. It can be implemented using a pipeline system with a desuperheating and pressure reducing device. Its function is to prioritize supplying the steam generated by the boiler in the early stage to the fuel atomization system.

[0052] Step 102: When the main steam pressure in the steam delivery pipeline reaches the first set pressure, adjust the steam pressure and temperature delivered to the fuel atomizing gun to the range required for atomization, and switch to operation of the steam atomizing gun.

[0053] In this step, the switching between the mechanical atomizing oil gun and the steam atomizing oil gun is achieved through a pressure sensor-triggered control command, ensuring a smooth transition of the combustion system. The required steam pressure range for atomization is 0.8 to 1.2 MPa. The required temperature range for atomization is 200 to 250 degrees Celsius. The initial set pressure is 1.0 MPa.

[0054] Step 103: When the main steam pressure or main steam temperature does not meet the requirements for shaft seal steam supply, steam is supplied to the turbine shaft seal system through the bypass steam supply pipeline, and the shaft seal steam supply pressure is adjusted to the range required for shaft seal sealing.

[0055] In this step, the bypass steam supply pipeline refers to the auxiliary pipeline connecting the main steam pipeline and the shaft seal system. Its flow rate can be controlled via an electrically operated regulating valve to maintain the shaft seal pressure when the main steam parameters are insufficient. The main steam pressure needs to be greater than or equal to 0.8 MPa to meet the shaft seal steam supply requirements. The main steam temperature needs to be greater than or equal to 250 degrees Celsius to meet the shaft seal steam supply requirements. The required range for shaft seal sealing is 0.02 to 0.03 MPa.

[0056] Step 104: When the main steam temperature and main steam pressure both meet the requirements for shaft seal steam supply, switch to supplying steam to the shaft seal system from the main steam pipeline and start the vacuum system.

[0057] In this step, the main steam pressure regulation adopts a closed-loop control system, which dynamically adjusts the valve opening by monitoring steam parameters in real time to ensure the stability of steam supply.

[0058] Step 105: Perform turbine start-up, grid connection, and load increase operations to start the unit.

[0059] In this embodiment, specifically, during the boiler ignition stage, the mechanical atomizing oil gun is first activated, and the steam delivery pipeline is simultaneously opened for preheating. When the main steam pressure reaches a preset threshold, the steam parameters are automatically adjusted to the atomization requirement range, completing the oil gun operation mode switch. While the main steam temperature or pressure is below standard, the bypass steam supply pipeline continuously supplies steam to the shaft seal system, maintaining the sealing pressure through flow regulation. Once the main steam parameters meet the shaft seal steam supply requirements, the system gradually switches to the direct main steam supply mode, while simultaneously activating the vacuum system to accelerate vacuum establishment. Finally, the unit achieves complete startup through turbine start-up, grid connection, and load increase operations.

[0060] In this embodiment, by setting up steam delivery pipelines from the boiler superheater to the fuel oil atomization system and bypass pipelines from the main steam supply to the shaft seal, the unit's autonomous startup under conditions of no backup steam source is achieved. This effectively solves the problems of insufficient shaft seal steam supply and lack of fuel oil atomization steam in the initial startup phase, significantly improves vacuum build-up speed and combustion stability, shortens startup time, and reduces dependence on external steam sources. Through a phased steam supply strategy and parameter feedback control, the steam demand of the two systems is effectively coordinated, avoiding steam resource conflicts between the systems.

[0061] In one embodiment of this specification, the turbine start-up, grid connection, and load increase operations are performed to achieve unit startup, including:

[0062] Step 1: Activate the turbine bypass system to increase the parameters of the main steam and reheat steam to the conditions required for turbine start-up;

[0063] In this step, the turbine bypass system refers to the steam regulating device connecting the main steam pipeline and the condenser. Specifically, it can be implemented using a fast-response electric regulating valve linked to a temperature sensor for control. This system is used to directly introduce a portion of the steam into the condenser during the startup phase, thereby accelerating the rise of the main steam parameters. The conditions required for turbine startup include, for example, a main steam pressure of 3.5 to 4.0 MPa and a temperature of 320 to 350 degrees Celsius.

[0064] Step 2: Stop the turbine bypass system and start the turbine and connect it to the grid at a constant speed;

[0065] Step 3: When the unit load reaches the set load, activate the auxiliary steam supply system and start the small steam turbine to complete the unit startup.

[0066] In this step, the set load refers to the state at which the unit reaches a specific power output after grid connection. This can be specifically fed back to the control system in real time through the load monitoring device. For example, when the power reaches 75 MW, subsequent operations are triggered. The auxiliary steam supply system refers to the steam supply network that provides driving steam to the small steam turbine. Specifically, it can be implemented using a combination of cold-section steam pipelines and pressure regulating valves, used to supply steam to auxiliary equipment during the load increase phase.

[0067] In this embodiment, specifically during unit startup, the temperature and pressure of the main steam and reheat steam are first increased to meet the conditions for turbine start-up by activating the turbine bypass system. During this stage, the regulating valves in the bypass system dynamically adjust their opening according to changes in steam parameters to ensure that the steam flow rate matches the parameters. When the steam parameters meet the start-up requirements, the bypass system stops operating, the turbine starts up and completes constant-speed synchronization, and is then connected to the power grid. As the load gradually increases to the set value, the auxiliary steam supply system is activated, supplying steam to the small turbine to drive its operation, ultimately achieving closed-loop control of the overall unit startup process.

[0068] In this embodiment, by controlling the entry and exit of the bypass system in stages and combining it with the precise triggering mechanism of the auxiliary steam system, the step-by-step optimization of the main steam parameters and the coordinated control of load increase are realized. This avoids the thermal shock of the turbine rotor caused by sudden changes in steam parameters and solves the problem of small turbine start-up delay caused by uneven steam distribution in units without backup steam source during the load increase phase. Through the timing linkage between the bypass system and the auxiliary steam supply, the main steam parameters are ensured to reach the standard quickly during the start-up phase, while providing stable steam supply conditions for subsequent load increases, thereby shortening the overall start-up time of the unit and reducing operational risks.

[0069] In one embodiment of this specification, the steam delivery pipeline is connected between the soot blowing steam source pipeline at the outlet of the boiler superheater partition screen and the fuel atomizing steam pipeline.

[0070] In this embodiment, the boiler superheater is a key component in a thermal power boiler, used to heat saturated steam into high-temperature, high-pressure superheated steam. The partition platen superheater outlet refers to the steam outlet location of the partition platen superheater, typically located in the upper part of the furnace. It is one of the earliest measurement points in the superheater system to obtain qualified steam; selecting this location as the steam intake point allows for early acquisition of usable steam, thus shortening start-up time. The soot blowing steam source pipeline is the existing steam pipeline used for the boiler's heating surface soot blowing system, usually led out from the superheater partition platen or the final stage superheater. This invention utilizes this pipeline as a readily available steam intake interface, avoiding the need for drilling holes in the superheater's main pipeline, reducing modification difficulty and safety risks. The fuel oil atomization steam pipeline refers to the pipeline system supplying steam to the boiler burner oil guns, used to break the fuel oil into fine oil droplets (steam atomization) to improve combustion efficiency. In this invention, this pipeline receives steam from the steam delivery pipeline, enabling direct operation of the steam atomization oil guns during the initial start-up phase, avoiding the combustion instability problems caused by using mechanical atomization oil guns.

[0071] In this embodiment, by connecting the steam delivery pipeline between the soot blowing steam source pipeline at the outlet of the superheater partition screen and the fuel atomizing steam pipeline, the boiler's self-generated steam is directly supplied to the fuel atomizing system during the initial startup phase, thereby improving steam utilization efficiency and reducing the complexity of system modification.

[0072] In one embodiment of this specification, when supplying steam to the shaft sealing system through a bypass steam supply pipeline, the method further includes:

[0073] Step 1: Monitor the changing trend between shaft seal steam supply pressure and condenser vacuum build-up rate in real time, and calculate the dynamic correlation between the two within a preset time window;

[0074] In this step, dynamic correlation refers to the degree of correlation between two parameters over time, calculated using statistical analysis methods. Specifically, it can be achieved using the Pearson correlation coefficient or a sliding window mutual information algorithm, used to quantify the actual impact of shaft seal steam supply pressure regulation on the vacuum build-up rate. The preset time window refers to a continuous time period used for data acquisition and analysis. Specifically, it can be a fixed-length time period or a time period dynamically adjusted according to the pressure change rate, used to capture the dynamic response characteristics of the system.

[0075] Step 2: When the dynamic correlation is lower than the set threshold and the vacuum build-up rate is consistently lower than the target rate, automatically increase the steam flow rate of the bypass steam supply pipeline until the dynamic correlation returns to the normal range.

[0076] In this step, the target rate refers to the minimum rate required to be achieved during the condenser vacuum build-up process. The specific rate can be set according to the unit startup procedures or historical operating data, and is used to determine whether the vacuum system is in a normal build-up state.

[0077] In this embodiment, specifically, during the initial startup phase of the unit, when steam is supplied to the shaft seal system via the bypass steam supply pipeline, the control system continuously collects real-time data on the shaft seal steam supply pressure and the condenser vacuum build-up rate. The dynamic correlation between the two is calculated using data sequences within a preset time window. When the correlation is detected to be lower than a set threshold and the vacuum build-up rate remains below the target value, it indicates that the current steam supply regulation has failed to effectively promote vacuum build-up. At this time, the opening of the regulating valve on the bypass steam supply pipeline is automatically controlled to increase the steam flow rate, thereby enhancing the sealing effect by increasing the shaft seal steam supply pressure, until the dynamic correlation between the vacuum build-up rate and the steam supply pressure returns to the normal range.

[0078] In this embodiment, intelligent adjustment of steam supply parameters is achieved through correlation analysis, which can promptly detect coordination problems between the steam supply system and the vacuum system, avoiding adjustment failures caused by parameter response lag. This embodiment effectively solves the start-up delay problem caused by the mismatch between shaft seal steam supply and vacuum build-up rate. It can automatically adjust the steam flow rate when the steam supply pressure is insufficient, ensuring that the shaft seal sealing effect and the vacuum build-up process remain coordinated, significantly shortening the unit's cold start-up time and reducing the frequency of manual intervention.

[0079] In one embodiment of this specification, after switching to steam atomizing oil gun operation, the method further includes:

[0080] Step 1: If an unstable combustion signal is detected, the decompression rate of the main steam to fuel atomization steam will be automatically reduced, and the parallel operation time of the mechanical atomization and steam atomization oil guns will be extended.

[0081] Step 2: Once the combustion has stabilized, completely withdraw the mechanical atomizing oil gun.

[0082] In this embodiment, the combustion instability signal refers to a signal captured by the flame monitoring device that indicates a combustion chamber pressure fluctuation exceeding a safety threshold or an abnormal frequency of flame brightness changes. This can be achieved through a linkage analysis using a high-frequency pressure sensor and an infrared camera to reflect abnormal combustion conditions in real time. Reducing the decompression rate from main steam to fuel atomization steam refers to slowing the rate of steam pressure decrease by adjusting the opening of the desuperheating and decompression device's actuator. This can be achieved using a step-by-step control mode of an electric regulating valve to prevent sudden changes in steam parameters that could degrade atomization quality. Extending the parallel operation time refers to maintaining the simultaneous operation of the mechanical atomizing oil gun and the steam atomizing oil gun. This can be achieved by dynamically adjusting the oil gun switching logic through the control system, providing a transition buffer period for the combustion system.

[0083] In this embodiment, specifically, during the initial operation of the steam atomizing oil gun, the combustion chamber heat load distribution may be disturbed due to fluctuations in steam parameters. When the flame monitoring system detects unstable combustion characteristics, the control system immediately sends a command to the desuperheating and pressure reducing device to adjust the steam pressure regulation rate from the usual 0.3 MPa decrease per minute to 0.1 MPa decrease per minute, while simultaneously maintaining the mechanical atomizing oil gun in operation. During this process, the mechanical atomizing oil gun provides basic combustion support, while the steam atomizing oil gun gradually increases its output proportion, and the parallel operation time of both is extended from the preset 5 minutes to 8-12 minutes. Once the combustion chamber pressure fluctuation returns to the normal range and flame image analysis confirms stability, the mechanical atomizing oil gun automatically shuts down.

[0084] In this embodiment, the switching parameters are dynamically adjusted by real-time monitoring of the combustion status. A rate control mechanism is introduced during the steam decompression process, and a heat load transition zone is formed by the parallel operation of dual oil guns, effectively suppressing combustion fluctuations. This embodiment solves the combustion instability problem caused by sudden parameter changes during the switching of steam atomization oil guns, avoids the risk of combustion interruption due to delayed manual intervention, ensures a smooth transition of the combustion system during the unit startup phase, and improves the success rate of autonomous startup.

[0085] In one embodiment of this specification, before activating the turbine bypass system, the following steps are also included:

[0086] Step 1: Determine whether the upward trend of the main steam pressure is continuous and without any downward fluctuations;

[0087] In this step, whether the main steam pressure rises continuously without any downward fluctuations refers to continuously collecting pressure data from the main steam pipeline using pressure sensors and calculating the pressure change rate and fluctuation amplitude within a preset time window. Specifically, this can be achieved by using a moving average algorithm combined with standard deviation calculation, which is used to identify whether there are abnormal fluctuations during the pressure rise process.

[0088] Step 2: If so, activate the bypass system to accelerate the reheater temperature rise;

[0089] In this step, activating the bypass system to accelerate reheater temperature rise means introducing a portion of the main steam into the reheater for heat exchange by opening the turbine bypass pipeline. This can be achieved using an electric regulating valve and temperature interlock control, which is used to raise the reheat steam temperature to the conditions required for turbine start-up.

[0090] Step 3: If not, suspend bypass operation and prioritize increasing the boiler combustion rate to a stable state before proceeding with the operation.

[0091] In this step, increasing the boiler combustion rate to a stable state means increasing the fuel supply and adjusting the air volume to achieve a balanced furnace heat load. This can be achieved using the fuel-air volume ratio adjustment module in the combustion control system, which is used to eliminate the main steam pressure fluctuation source.

[0092] In this embodiment, specifically during the unit startup phase, pressure sensors monitor the pressure changes in the main steam pipeline in real time and input the data into the control system for trend analysis. If the pressure curve shows a continuous upward trend and the standard deviation is below a set threshold, it is determined to be a stable upward trend. At this time, the electric regulating valve of the bypass system is automatically opened to introduce main steam into the reheater to accelerate the temperature rise. If the pressure fluctuation is detected to exceed the allowable range or a downward trend is observed, the bypass system activation command is suspended, and instead, the fuel oil supply is increased and the air-fuel ratio is optimized through the combustion control system. After the pressure recovers and stabilizes, the bypass activation operation is re-executed.

[0093] In this embodiment, the coordinated control of pressure trend judgment and combustion rate priority adjustment effectively avoids system disturbances caused by pressure instability, while ensuring that the reheater heating process matches the boiler combustion state. This embodiment solves the problem of steam parameter fluctuations caused by premature bypass system activation. Through the linkage control of pressure trend prediction and combustion adjustment, the safe and reliable activation of the bypass system is achieved, the reheater heating time is shortened, and the risk of equipment wear caused by abnormal pressure is reduced.

[0094] In one embodiment of this specification, the unit startup method without a backup steam source further includes:

[0095] Establish a priority coordination mechanism between fuel atomization steam demand and shaft seal steam supply demand.

[0096] Specifically, a priority coordination mechanism will be established between the demand for fuel atomized steam and the demand for shaft seal steam, including:

[0097] When the decrease in shaft seal steam pressure is detected to last for more than the first set time, or the shaft seal steam flow rate is lower than the minimum sealing flow rate, the regulating valve on the fuel atomizing steam branch is closed or throttled.

[0098] Available steam is preferentially distributed to the shaft seal steam supply system, and combustion stability is maintained by increasing the number of operating oil guns or adjusting the combustion air ratio.

[0099] In this embodiment, the priority coordination mechanism refers to dynamically adjusting the steam distribution strategy of different systems based on the steam supply and demand status. Specifically, it can use pressure sensors to monitor the changing trend of shaft seal steam supply pressure, combined with flow meters to detect shaft seal steam supply flow, and trigger priority adjustment through control system logic. This mechanism prioritizes the sealing needs of the shaft seal system when steam resources are limited by real-time monitoring of key parameters, thus preventing vacuum system damage. The combustion air ratio adjustment refers to changing the oxygen distribution in the burner area by adjusting the opening of the secondary damper. Specifically, it can use the damper actuator for linkage control to maintain flame stability while reducing the amount of fuel atomized steam, preventing combustion interruption.

[0100] In this embodiment, specifically, when the total steam volume is insufficient during the unit startup phase, and the shaft seal steam supply pressure continues to drop or the flow rate falls below the minimum value required for sealing, the regulating valve of the fuel atomization steam branch will be automatically reduced or closed. At this time, steam is preferentially delivered to the shaft seal system via the bypass pipeline. Simultaneously, the combustion control system increases the number of operating oil guns, for example, switching from two sets of oil guns to three sets, and adjusts the burner secondary air damper opening to optimize the fuel-air mixing ratio. This dynamic adjustment method ensures the sealing effect of the shaft seal system and maintains stable furnace heat load through combustion parameter compensation, avoiding the risk of combustion oscillation or flameout due to steam distribution imbalance.

[0101] In this embodiment, by establishing automated priority control logic, dynamic allocation of steam resources between the shaft seal steam supply and the fuel atomization system is achieved. Simultaneously, combined with combustion parameter compensation technology, combustion stability is maintained while ensuring the operation of critical systems, effectively solving the startup failure problem caused by steam competition among multiple systems in scenarios without backup steam sources. This embodiment can automatically identify the urgent needs of the shaft seal system when the total steam volume is insufficient, prioritizing the integrity of the turbine vacuum system. At the same time, it maintains stable boiler thermal conditions through combustion system parameter adjustments, avoiding shaft seal leakage or combustion interruption accidents caused by steam distribution imbalances, significantly improving the autonomous startup success rate of units without backup steam sources.

[0102] In one embodiment of this specification, a dual-source superimposed transition method is adopted during the switching from bypass steam supply to main steam supply, including:

[0103] First, maintain the bypass steam supply, then slowly introduce the main steam supply;

[0104] After the main steam supply pressure stabilizes and remains stable for a preset time period (2 minutes), the bypass steam supply pipeline is gradually shut off to complete a smooth switchover.

[0105] In this embodiment, the dual-source superposition transition method refers to operating both bypass steam supply and main steam supply simultaneously when switching steam sources. Seamless switching is achieved by gradually adjusting the steam supply ratio. Specifically, this can be implemented using a pressure closed-loop control system linked with an electric regulating valve. The opening of the bypass valve is dynamically adjusted by monitoring the main steam pressure change trend in real time. The bypass steam supply pipeline is an auxiliary steam supply channel connecting the main steam pipeline and the shaft seal steam supply system. It is specifically implemented using alloy steel pipes and a fast-response regulating valve to maintain the continuity of the shaft seal steam supply pressure during the initial switching phase. Stable main steam supply pressure means that the steam pressure fluctuation range output from the main steam pipeline is less than a set threshold. This is specifically achieved by real-time feedback from a pressure sensor to the control system. When the pressure value is continuously monitored within the target range for more than a set duration, the system is determined to have entered a stable state.

[0106] In this embodiment, specifically during the switching operation, the bypass steam supply pipeline remains open, while the regulating valve of the main steam supply pipeline opens slowly at a preset rate. The main steam pressure sensor collects data in real time and transmits it to the control system. When the main steam supply pressure reaches the target value and remains there for more than 2 minutes, the electric regulating valve of the bypass pipeline begins to close gradually in a stepped manner. After each closing action, the system waits for the pressure feedback signal to stabilize before proceeding to the next step. During this process, the pressure fluctuation of the shaft seal steam supply header is controlled within the sealing requirements.

[0107] In this embodiment, by superimposing steam supply and staged switching, the risk of sudden changes in steam supply pressure is eliminated, avoiding shaft seal failure caused by drastic changes in steam parameters. This embodiment achieves a smooth transition of steam parameters during steam source switching, ensuring that the steam supply pressure of the shaft seal system is always maintained within the range required for sealing, effectively preventing abnormal vacuum build-up rate or damage to shaft seal components due to thermal stress impact, and improving the safety and reliability of the start-up process of units without a backup steam source.

[0108] In one embodiment of this specification, the timing of opening the bypass steam supply pipeline is related to the rate of main steam temperature rise after boiler ignition, including:

[0109] When the main steam temperature rise rate is greater than 1.5℃ / min, the bypass steam supply pipeline is opened with a delay.

[0110] When the temperature rise rate is between 0.8 and 1.5℃ / min, the preset program will be activated.

[0111] When the temperature rise rate is below 0.8℃ / min, start the machine in advance and increase the steam supply.

[0112] In this embodiment, the timing of opening the bypass steam supply pipeline refers to dynamically adjusting the steam supply intervention point based on the main steam temperature rise rate after boiler ignition. Specifically, this can be achieved by real-time acquisition of main steam temperature data by a temperature sensor and calculation of the rate of change. The main steam temperature rise rate refers to the increase in main steam temperature per unit time, and its value can be obtained by continuous monitoring by a temperature sensor and transmission to the control system for differential calculation. Preset program opening refers to triggering the bypass valve action according to pre-set logical conditions, such as gradually opening the valve according to the time gradient when the temperature rise rate is in the middle range. Early opening and increased steam supply refers to actively increasing the bypass steam flow rate to compensate for the steam supply delay caused by insufficient boiler combustion when the temperature rise rate is low.

[0113] In this embodiment, specifically, the rate of increase in main steam temperature is monitored in real time during the initial stage of boiler ignition. When the temperature rise rate exceeds 1.5℃ / min, it is determined that the boiler combustion intensity is high. At this time, the opening of the bypass steam supply pipeline is delayed to avoid premature steam supply that could cause high-temperature steam impact on the shaft seal system. When the temperature rise rate is in the range of 0.8 to 1.5℃ / min, it indicates that combustion is in a stable rising stage. At this time, the steam supply is gradually increased according to the preset valve opening curve. When the temperature rise rate is below 0.8℃ / min, it is determined that there is a lag in boiler combustion. At this time, the bypass pipeline is opened in advance and the steam flow rate is increased to compensate for the insufficient main steam parameters through active steam supply, ensuring the timely establishment of the sealing pressure of the shaft seal system.

[0114] In this embodiment, by establishing a correlation between the timing of steam supply and the rate of main steam temperature rise, the steam supply strategy can be adjusted in real time according to the actual combustion state of the boiler. This avoids the thermal shock of high-temperature steam to the shaft seal system and solves the problem of slow vacuum establishment caused by insufficient steam supply during low-load stages. This embodiment achieves dynamic matching between bypass steam supply and boiler combustion state, effectively maintaining the stability of shaft seal steam supply pressure during the initial unstable main steam parameter stage of startup, shortening the vacuum system establishment time, and preventing damage to shaft seal components caused by sudden changes in steam parameters.

[0115] In a specific embodiment of the present invention, a 300MW subcritical thermal power generating unit without a backup steam source is provided, the overall structure of which includes the following key components and their functions:

[0116] Boiler system:

[0117] Boiler body: Used to burn fuel (such as oil or pulverized coal) to produce high-temperature and high-pressure steam.

[0118] Boiler superheater: Located in the flue at the tail end of the boiler, it is responsible for heating the steam generated by the boiler to a superheated state, and then delivering it to the fuel atomization system through the steam delivery pipeline.

[0119] Divider screen superheater: Located in the upper part of the furnace, it is used for initial heating of steam. Its outlet steam parameters are relatively stable, making it suitable as an early steam source.

[0120] Steam transmission pipeline system:

[0121] Soot blowing steam source pipeline: The steam pipeline originally used for the soot blowing system has been modified to draw steam from the outlet of the partition screen superheater.

[0122] Fuel atomization steam pipeline: The steam drawn from the soot blowing steam source pipeline is transported to the fuel atomization system. The pipeline is equipped with a de-heating and pressure reducing device, a pressure sensor and a temperature sensor to adjust the steam parameters to the required range for atomization (pressure 0.8–1.2MPa, temperature 200–250℃).

[0123] Fuel atomization system:

[0124] Mechanical atomizing oil gun: Used in the initial stage of boiler ignition to atomize fuel oil mechanically.

[0125] Steam atomizing oil gun: It automatically switches to use after the steam parameters meet the standard, and improves combustion efficiency through steam atomization.

[0126] Control system: Real-time monitoring of steam parameters and control of oil gun switching to ensure stable combustion.

[0127] Main steam pipe:

[0128] It connects the boiler superheater outlet to the turbine high-pressure cylinder to deliver high-temperature and high-pressure main steam in order to maintain the sealing of the shaft seal.

[0129] Shaft seal steam supply system:

[0130] Shaft seal steam supply header: supplies sealing steam to the turbine shaft seals to prevent air from leaking into the vacuum system.

[0131] Bypass steam supply pipeline: DN200 alloy steel pipeline, connecting the main steam pipeline and the shaft seal header, equipped with electric regulating valve, check valve and flow monitoring device, used for initial steam supply during startup.

[0132] Main steam supply pipeline: After the main steam parameters meet the standards (pressure ≥ 0.8 MPa, temperature ≥ 250℃), steam is supplied to the shaft seal system.

[0133] Steam turbine system:

[0134] Steam turbine body: includes high-pressure cylinder, intermediate-pressure cylinder and low-pressure cylinder, used to convert steam thermal energy into mechanical energy.

[0135] Vacuum system: Used to establish and maintain condenser vacuum, thereby improving turbine efficiency.

[0136] Bypass system: including primary and secondary bypasses, used to regulate the parameters of main steam and reheat steam during the start-up phase to accelerate the achievement of turbine start-up conditions.

[0137] Auxiliary steam system:

[0138] Cold section to auxiliary steam pipeline: put into operation after the load is increased to 75MW, to provide steam for auxiliary equipment such as small steam turbines.

[0139] Control and monitoring system:

[0140] DCS control system: integrates sensor signals such as pressure, temperature, and flow to realize functions such as automatic adjustment of steam parameters, oil gun switching, and priority coordination of shaft seal steam supply.

[0141] Alarm and protection system: Set alarm thresholds for overpressure, overtemperature, low flow, etc., to ensure safe startup process.

[0142] System workflow overview:

[0143] During unit startup, the unit is first ignited via a mechanical atomizing oil gun, and the steam delivery pipeline is simultaneously opened to supply the fuel atomization system with early-stage steam from the superheater. When the main steam pressure reaches 1.0 MPa, the system automatically switches to the steam atomizing oil gun. The shaft sealing system initially supplies steam via a bypass pipeline; once the main steam parameters meet the requirements, it switches to main steam supply and activates the vacuum system. Subsequently, the steam parameters are increased through the turbine bypass system to complete start-up, grid connection, and load increase. Finally, the auxiliary steam system is activated, achieving a complete unit startup.

[0144] This embodiment achieves autonomous, efficient, and safe startup of the unit under conditions of no backup steam source through systematic transformation and intelligent control, significantly improving startup efficiency and economy.

[0145] Based on the same general inventive concept, this invention also protects a unit starting device without a backup steam source, such as... Figure 2 As shown, Figure 2 This is a schematic diagram of the unit starting device without a backup steam source provided in an embodiment of the present invention. The unit starting device without a backup steam source provided by the present invention will be described below. The unit starting device without a backup steam source described below can be referred to in correspondence with the unit starting method without a backup steam source described above.

[0146] A steam delivery pipeline is installed between the boiler superheater and the fuel atomization system of the unit, and a bypass steam supply pipeline is installed between the main steam pipeline and the shaft seal steam supply system.

[0147] The unit starting device without a backup steam source includes:

[0148] The ignition and steam pre-ignition module 201 uses a mechanical atomizing oil gun to ignite the boiler and open the steam delivery pipeline;

[0149] When the main steam pressure in the steam delivery pipeline reaches the first set pressure, the fuel atomization switching module 202 adjusts the steam pressure and temperature delivered to the fuel atomization gun to the range required for atomization and switches to operation of the steam atomization gun.

[0150] When the main steam pressure or main steam temperature does not meet the requirements for shaft seal steam supply, the shaft seal steam supply module 203 supplies steam to the turbine shaft seal system through the bypass steam supply pipeline and adjusts the shaft seal steam supply pressure to the range required for shaft seal sealing.

[0151] When the main steam temperature and main steam pressure both meet the requirements for shaft seal steam supply, the shaft seal steam supply switching module 204 switches to supplying steam to the shaft seal system from the main steam pipeline and starts the vacuum system.

[0152] The unit grid connection control module 205 performs turbine start-up, grid connection and load increase operations to realize unit startup.

[0153] Figure 3 This is a schematic diagram of the start-up steam for a 300MW subcritical unit without a backup steam source, provided in an embodiment of the present invention. The overall process is described below:

[0154] 1. The earliest available steam source after boiler ignition:

[0155] 1.1 Flame establishment immediately opens valve L512130 (separator outlet header → soot blowing steam header).

[0156] 1.2 The steam pressure at this location is 0.3–0.5 MPa and the temperature is 280–320℃. After the first stage of cooling, the temperature drops to 200–250℃, and then the pressure is stabilized to 0.8–1.2 MPa by the pressure reducing valve, which becomes the primary steam source for "fuel atomization steam" and can be directly put into operation for steam atomization oil gun, eliminating the need for mechanical oil gun replacement.

[0157] 2. Early steam supply to the shaft seal (main steam parameters have not yet met the standards):

[0158] 2.1 If the main steam pressure is <0.8MPa and the temperature is <250℃, the shaft seal requirements are not met. At this time, a bypass is led out from the main steam pipeline, and after passing through the electric regulating valve and the check valve, it is connected to the shaft seal steam supply header to maintain a shaft seal pressure of 0.02–0.03MPa and start vacuuming.

[0159] 3. Functions of each section of the heating surface during the parameter ramp-up phase:

[0160] 3.1 The flue gas first flows through the vertical low-pressure outlet header, which provides initial heating to the feedwater, but does not directly contribute to the start-up steam source.

[0161] 3.2 Subsequently, steam enters the inlet header of the partition screen, absorbs heat in the upper part of the furnace, and then collects at the outlet header of the partition screen.

[0162] 3.3 Steam continues to flow into the rear screen inlet header → rear screen outlet header, and the temperature is further increased; when the rear screen outlet pressure is ≥0.6MPa and the temperature is ≥300℃, it can be used as a supplementary steam source for "shaft seal bypass steam supply", and run in parallel with the original bypass to improve the vacuum establishment speed.

[0163] 3.4 Finally, steam enters the inlet header of the last stage superheater → the outlet header of the last stage superheater. The target parameters here are 3.5–4.0 MPa and 320–350℃. After the target is met, the bypass is stopped, and the system is switched to "formal main steam supply to shaft seal" and the turbine is started.

[0164] 4. Secondary use of de-cooling and pressure-reducing nodes:

[0165] 4.1 If the final stage outlet temperature exceeds 380℃, activate the secondary desuperheating system to spray water into the shaft seal steam supply pipeline to ensure that the shaft seal steam superheat is ≤50℃, thus preventing damage to the graphite ring.

[0166] 4.2 When the unit load rises to 75MW, the cold section reheat steam (not shown in the figure) is sent in reverse through the "cold section to auxiliary steam" pipeline to the auxiliary steam header near the rear screen outlet header, providing "auxiliary steam" for the small steam turbine and deaerator, thus completing the startup closed loop.

[0167] Figure 4 This is a schematic diagram of the structure of the electronic device provided in an embodiment of the present invention.

[0168] like Figure 4 As shown, the electronic device may include a processor 410, a communications interface 420, a memory 430, and a communication bus 340. The processor 410, communications interface 420, and memory 430 communicate with each other via the communication bus 340. The processor 410 can call logical instructions from the memory 430 to execute a unit startup method without a backup steam source.

[0169] Furthermore, the logical instructions in the aforementioned memory 430 can be implemented as software functional units and, when sold or used as independent products, can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0170] On the other hand, the present invention also provides a computer program product, which includes a computer program that can be stored on a non-transitory computer-readable storage medium. When the computer program is executed by a processor, the computer is able to execute the unit startup method without backup steam source provided by the above methods.

[0171] In another aspect, the present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the unit startup method without backup steam source provided by the above methods.

[0172] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without any creative effort.

[0173] Through the above description of the embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus necessary general-purpose hardware platforms, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solutions, in essence or the part 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 computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods described in the various embodiments or some parts of the embodiments.

[0174] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method of starting a unit without a reserve steam source, characterized by, A steam delivery pipeline is arranged between a boiler superheater and a fuel oil atomization system of the unit, and a bypass steam supply pipeline is arranged between a main steam pipeline and a shaft seal steam supply system, and the method comprises the following steps: A mechanical atomization oil gun is used to ignite the boiler, and the steam delivery pipeline is started; When the main steam pressure in the steam delivery pipeline reaches a first set pressure, the steam pressure and temperature delivered to the fuel oil atomization oil gun are adjusted to a required range for atomization, and the steam atomization oil gun is switched to operation; When the main steam pressure or the main steam temperature does not reach the shaft seal steam supply requirement, steam is supplied to the steam turbine shaft seal system through the bypass steam supply pipeline, and the shaft seal steam supply pressure is adjusted to a required range for shaft seal sealing; When the main steam temperature and the main steam pressure both reach the shaft seal steam supply requirement, steam is supplied to the shaft seal system from the main steam pipeline, and a vacuum pumping system is started; The steam turbine is started, grid-connected and load-raising operation is performed, and the unit is started.

2. The method of claim 1, wherein, The steam turbine is started, grid-connected and load-raising operation is performed, and the unit is started, and the method comprises the following steps: The steam turbine bypass system is started, and the parameters of the main steam and the reheated steam are raised to a required condition for steam turbine starting; The steam turbine bypass system is stopped, and the steam turbine is started and grid-connected at a constant speed; When the unit load is raised to a set load, the auxiliary steam supply system is started, and a small steam turbine is started, and the unit is started.

3. The method of claim 1, wherein, The steam delivery pipeline is connected between a soot blowing steam source pipeline at an outlet of a boiler superheater partition screen and a fuel oil atomization steam pipeline.

4. The method of claim 2, wherein, When steam is supplied to the shaft seal system through the bypass steam supply pipeline, the method further comprises the following steps: The change trend between the shaft seal steam supply pressure and the condenser vacuum establishment rate is monitored in real time, and a dynamic correlation degree of the two in a preset time window is calculated; When the dynamic correlation degree is lower than a set threshold value, and the vacuum establishment rate continuously falls below a target rate, the steam flow of the bypass steam supply pipeline is automatically increased until the dynamic correlation degree returns to a normal range.

5. The method of claim 1, wherein, After the steam atomization oil gun is switched to operation, the method further comprises the following steps: If an unstable combustion signal is detected, the pressure reduction rate of the main steam to the fuel oil atomization steam is automatically reduced, and the mechanical atomization and the steam atomization oil gun are operated in parallel for an extended time; After the combustion is stable, the mechanical atomization oil gun is completely withdrawn.

6. The method of claim 2, wherein, Before the steam turbine bypass system is started, the method further comprises the following steps: It is judged whether the main steam pressure rising trend is continuous and without falling fluctuation; If yes, the bypass system is started to accelerate the reheater temperature rise; If no, the bypass starting is suspended, the boiler combustion rate is raised to a stable state, and then the starting operation is performed.

7. The method of claim 1, wherein, The method further comprises the following steps: A priority coordination mechanism between the fuel oil atomization steam requirement and the shaft seal steam supply requirement is established.

8. The method of claim 7, wherein, The priority coordination mechanism between the fuel oil atomization steam requirement and the shaft seal steam supply requirement comprises the following steps: When it is detected that the shaft seal steam supply pressure falling trend continuously exceeds a first set time length, or the shaft seal steam supply flow is lower than a minimum sealing flow, the adjusting valve on the fuel oil atomization steam branch is closed or throttled; The available steam is preferentially distributed to the shaft seal steam supply system, and the combustion is maintained stable by adjusting the combustion air ratio.

9. The method of claim 1, wherein, In the process of switching from the bypass steam supply to the main steam supply, a double-source superposition transition mode is adopted; The double-source superposition transition mode comprises the following steps: The bypass steam supply is maintained first, and then the main steam supply is introduced. After the main steam supply pressure is stable and lasts for a preset time period, the bypass steam supply pipeline is closed, and the switching is completed.

10. A unit startup device without a reserve steam source, characterized by comprising: The device is characterized in that a steam delivery pipeline is arranged between a boiler superheater and a fuel atomization system of the unit, a bypass steam supply pipeline is arranged between a main steam pipeline and a shaft seal steam supply system, and the device comprises: An ignition and steam pre-ignition module is used to ignite the boiler by using a mechanical atomization oil gun and to open the steam delivery pipeline; A fuel atomization switching module is used to adjust the steam pressure and temperature delivered to the fuel atomization oil gun to a required range for atomization and to switch to steam atomization oil gun operation when the main steam pressure in the steam delivery pipeline reaches a first set pressure; A shaft seal steam supply guarantee module is used to supply steam to the steam turbine shaft seal system through the bypass steam supply pipeline and to adjust the shaft seal steam supply pressure to a required range for shaft seal sealing when the main steam pressure or the main steam temperature does not reach a shaft seal steam supply requirement; A shaft seal steam supply switching module is used to switch to supply steam to the shaft seal system from the main steam pipeline and to start a vacuum pumping system when the main steam temperature and the main steam pressure both reach the shaft seal steam supply requirement; A unit grid connection control module is used to perform steam turbine spin-up, grid connection and load lifting operations to realize unit startup.

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