Full-process automatic operation control method for sub-medium pressure turbine island

Abstract

The invention relates to a full-process automatic operation control method for a sub-medium-pressure steam turbine island. The method comprises the following steps of (1) starting inspection, (2) auxiliary engine starting, (3) speed increasing, (4) grid connection, (5) load increasing, (6) automatic shutdown and (7) bypass automatic operation under abnormal working conditions. According to the scheme, operation of operators is reduced, and the automation level of the unit is improved. The invention further provides a control method for economical and safe operation of the steam turbine based on boundary control.

Description

Technical Field

[0001] The invention relates to a control method, in particular to a full-process automatic operation control method for a sub-medium pressure steam turbine island, and belongs to the technical field of steam turbine control. Background Art

[0002] my country insists on giving top priority to energy conservation and resource conservation, and strengthening the coordinated transformation of production and consumption. We will promote clean and efficient use of coal and technological research and development, and accelerate the construction of a new energy system. We will improve the energy consumption, carbon emission management and non-fossil energy target system, and improve the green energy consumption promotion mechanism. We will promote energy conservation and carbon reduction in key areas of high-energy-consuming industries and improve energy efficiency. In the fields of steel and petrochemicals, efficient, clean and green production methods are the main goals of industry development.

[0003] The low-pressure steam pipeline network of Meigang Company supplies steam to various steam user units in the Meigang area, which not only meets the daily production needs of users, but also recycles the steam generated by the waste energy of sintering ring coolers, steelmaking converters and hot rolling heating furnaces. The 2.1MPa / 350℃ sub-medium pressure steam is sent to the steam turbine to do work, and then the steam is extracted for heat supply to achieve energy cascade utilization, which can effectively reduce the energy consumption of the steelmaking process, solve the white pollution problem caused by steam emission, and eliminate the noise generated by steam emission, achieving the three goals of environmental protection, energy saving and emission reduction, and creating benefits.

[0004] A sub-medium pressure steam generator unit adopts an extraction condensing steam turbine with an inlet steam parameter of 2.1MPa / 350℃. The low-pressure supplementary steam parameter of the steam turbine is 0.5MPa / 190℃. In addition, the steam turbine has the ability to extract steam for heating, with an extraction pressure of 1.0MPa and a temperature of 230℃. Although the unit capacity is not large and the parameters are not high, the system is complex and requires a lot of monitoring and operation items. During the unit startup process, factors such as temperature difference, displacement, stress and vibration have a direct impact on the safety of the unit. If it is manually started, the operator needs to concentrate on a lot of monitoring and operation. In order to reduce human errors, the startup needs to be completed in the shortest time while ensuring the safety of the unit to improve the economy of the unit operation. More importantly, since the unit needs to extract steam for heating, when the unit is in an abnormal operating condition, the inlet steam needs to be bypassed in time to reduce temperature and pressure and then supplied to the user, so higher requirements are put forward for the safe and economical operation and process control of the unit, and the full process of the unit needs to be automatically operated. Therefore, a new solution is urgently needed to solve the above technical problems. Summary of the invention

[0005] The present invention is aimed at the problems existing in the prior art, and provides a full-process automatic operation control method for a sub-medium pressure steam turbine island, which can realize the full-process automatic control functions of the steam turbine island from startup inspection, deaeration system, condensate system, circulating water system, lubricating oil system, EH oil system, vacuum system, pipe heating system, shaft seal system, automatic lock, operation, friction inspection, medium-speed warm-up, until the rated speed, automatic grid connection, automatic load control, and corresponding automatic shutdown function, abnormal condition bypass automatic operation function, reducing the operation of operating personnel and improving the automation level of the unit. The present invention also provides a control method for economical and safe operation of steam turbines based on boundary control.

[0006] In order to achieve the above-mentioned object, the technical solution of the present invention is as follows: the present invention provides a full-process automatic operation control method of a steam turbine island, and the basic steps include:

[0007] Step 1. Start the inspection, such as Figure 1 As shown in the figure, the startup inspection includes the inspection of various steam turbine auxiliary systems: deaerator system, condensate system, lubricating oil system, turning gear, EH oil, shaft seal system, vacuum system, valve inspection, instrument inspection, circulating water system inspection, initialization of sequential control system, and detection of corresponding parameters. Before starting, it is necessary to start the auxiliary system equipment and the auxiliary machine automatic test. Before starting, the steam quality judgment before the steam turbine is started can be realized and the automatic warm valve inspection can be performed; at the same time, the steam turbine can be reset when the conditions are met.

[0008] Step 2. Auxiliary machine start-up sequence,

[0009] The general sequence of auxiliary engine startup is as follows: Figure 2 Shown

[0010] 2.1 Unit status judgment: According to the starting procedures of this type of steam turbine, the starting status of the unit is automatically judged through program control: there are 4 starting modes: cold, warm, hot and extremely hot. For steam turbines, it is determined by the temperature of the upper metal (inner wall) of the high-pressure front cylinder.

[0011] 2.2 Circulating water system startup sequence: Figure 3 As shown, this step is to check the sequential control mode of circulating water inlet and outlet electric valves, circulating pump inverter, circulating pump high-voltage switch cabinet and other equipment. The circulating pump outlet butterfly valve is closed, the circulating pump inlet electric door and circulating pump outlet electric door are opened, KM3 is opened, KM1, KM2, and high-voltage switch cabinet are closed, the circulating water pump inverter is started, and the frequency is automatically increased. After the operating frequency is reached, KM3 is closed, KM1, KM2 are opened, and the standby pump interlock protection is put into operation; the normal operation of the circulating water system is realized.

[0012] 2.3 Deaeration system startup sequence: Figure 4As shown, this step checks the allowed sequential control mode of the electric valves related to the deaerator system; the deaerator water replenishment protection interlock is automatically put into operation, the deaerator emergency drainage electric valve interlock is automatically put into operation, and the deaerator liquid level and pressure are automatically put into operation. When the load of the standby unit is greater than 5MW, the secondary pumping to deaerator electric valve and the secondary pumping to deaerator check valve are put into operation.

[0013] 2.4 Condensate start-up sequence: Figure 5 As shown, this step is to check the condensate pump outlet electric valve, condenser cooling water inlet and outlet electric doors, condensate pump recirculation valve, condensate pump and other equipment in the allowed sequential control mode. Open the condensate pump recirculation valve, the electric gate valve in front of the condensate feed water regulating valve, the condensate feed water regulating valve is put into automatic mode, and the condensate main pipe pressure is set to 0.6MPa to achieve the normal operation of the condensate pump to the deaerator feed water circuit, put into the pump valve interlock of the condensate pump outlet electric valve, start the condensate pump and put it into automatic mode, set the given target value, and put the standby pump interlock protection into place.

[0014] 2.5 Lubricating oil system startup sequence: Figure 6 As shown, this step performs AC lubricating oil pump inspection, allows sequential control mode inspection, performs smoke exhaust fan operation inspection, starts the smoke exhaust fan and lubricating oil pump, and activates standby pump interlock protection.

[0015] 2.6 Crank start sequence: Figure 7 As shown, this step performs a check on the cranking permission sequential control mode; performs a pre-start check, including whether the oil pressure is normal, whether the main shaft speed is 0rpm, whether the cranking control box is remotely controlled, etc.; and starts the cranking equipment.

[0016] 2.7 Steam turbine regulation system steps: Figure 8 As shown, this step performs an EH oil pump sequential control mode check; when the EH oil temperature is greater than 20° and less than 60°, and the oil pressure is greater than 16MPa and less than 11.2MPa, start the EH oil pump; perform ETS braking, ETS reset, and ETS locking, and then perform ETS braking, ETS reset, and ETS locking; perform valve pulling and medium and high adjustment valve switching experiments to ensure that the steam turbine regulation can operate normally.

[0017] 2.8 Bypass pipe warming steps: Fig. 9 As shown, this step is to check the sequential control mode of the drain, cooling water and other valves; open the first-level drain valve: the drain valve in front of the electric door of the main steam mother pipe on the furnace side, and the drain valve in front of the high-pressure bypass; when the high-pressure bypass inlet pressure reaches 0.1MPa, open the minimum valve position control of the high and low bypass regulating valves.

[0018] 2.9 Vacuum start-up sequence: Fig.10As shown, this step checks the condenser vacuum water supply solenoid valve, condenser vacuum breaking electric valve, and vacuum pump to allow sequential control mode; checks whether the condenser cooling water inlet and outlet electric valves are open; starts the condenser vacuum water supply solenoid valve to supply water, and when the water level in the separator is above 75mm, closes the condenser vacuum breaking electric valve and starts the vacuum pump; starts the standby vacuum pump interlock protection; and starts the low-pressure cylinder water spray interlock protection.

[0019] 2.10 Shaft seal start-up sequence: Fig.11 As shown, this step checks the steam seal pipe drain control valve, shaft fan, etc. in the permitted sequential control mode; turns on the shaft fan, puts the steam seal pipe drain control valve interlock protection into operation, the pressure equalizing box exhaust to six-stage extraction steam regulating valve is automatically put into operation and sets the target given value, the pressure equalizing box exhaust electric regulating valve is automatically put into operation and sets the target given value, the pressure equalizing box auxiliary steam / main steam (auxiliary steam is selected for cold and warm states, and main steam is selected for hot and extremely hot states) regulating valve is automatically put into operation and sets the target given value, the pressure equalizing box water spray regulating valve is automatically put into operation and sets the target given value, and the high-pressure cylinder rear shaft seal leakage water spray regulating valve is automatically put into operation and sets the target given value.

[0020] Step 3: Speed-up sequence,

[0021] 3.1 As Fig.12 As shown, after the auxiliary engine is started, when the temperature before and after the main steam electric door matches (select the judgment conditions according to the unit status, the same below), the pressure before and after the main steam electric door matches, the superheat before and after the main steam electric door matches, the high-speed valve is closed, the EH oil system is normal, and the DEH system is normal, the unit can enter the speed increase sequence, and automatically select the initial warm-up target value, the speed increase rate and the warm-up time through the status judgment program, and then realize the rush, warm-up, and constant speed. Unit status judgment, automatic ETS reset by the operator, lock the main steam valve, prepare for the rush mode, allow the rush, drain the start side, friction check, low and medium speed warm-up (this step is automatically skipped in non-cold state), rated speed.

[0022] 3.2 Rated speed: Fig.12 As shown, the thermal stress of each main body component is monitored during the speed increase process; the margin of the cylinder body is calculated in real time. The allowable range of the lifting and lowering rate of the computer unit is calculated based on the thermal stress margin. When the calculated value of the thermal stress exceeds the allowable range, the starting speed of the unit needs to be changed. Then this module recalculates the rate of change of the speed and load based on the thermal stress margin, and sends an optimized starting speed request to the control system. The component only selects the cylinder inner cylinder, and the cylinder thermal stress calculation temporarily uses the cylinder inner wall. The smaller value of the rate of protection calculated based on the cold, warm, hot, and extremely hot state main engine recommended lifting rate and temperature margin is taken as the actual operation lifting rate.

[0023] Step 4. Grid connection sequence: Fig.13As shown, the unit can automatically connect to the grid, automatically carry the initial load, and increase the load according to the operating parameter curve provided by the main engine manufacturer. The procedure for the steam turbine unit to connect to the grid is: closing the demagnetization switch, remote control magnetization, automatic synchronization of DEH, synchronization reset, synchronization power on, synchronization power on, select synchronization point #2, closing permission, synchronization start, and synchronization reset after connecting to the grid.

[0024] Step 5. Load increasing sequence: Fig.14 As shown in the figure, the task of controlling the steam turbine generator from the initial load until the target load is reached. The target load can be given by the operator or specified in advance by other means. The controlled load change rate takes the lowest value of the following three change rates: the load change rate determined by stress changes; the load change rate given by the operator based on various reasons, including the operating conditions of other equipment in the power plant; the load change rate given by the DCS system. The system can automatically change the load change rate and generate load maintenance according to the current operating status of the unit. During load control, the system continuously monitors changes in turbine dynamic parameters such as pressure, temperature, thermal stress, vibration, expansion, etc., and alarms when the limit is exceeded, and generates maintenance or shutdown when necessary.

[0025] Step 6. Automatic shutdown: It is necessary to check the drain system interlock, deaerator, condensate, and shaft seal system. Put the bypass into automatic setting of main steam pressure and reheat steam pressure. Before load reduction, the operation mode is changed to power control mode. The axial displacement and expansion difference of the unit body are monitored throughout the load reduction process. If they are too large, the load reduction is suspended. After the load drops to 0, the operation mode determines whether the unit is shut down. After the shutdown speed drops to 0, the cranking is started, and other auxiliary systems remain in working condition.

[0026] Step 7: Automatic bypass operation under abnormal conditions: Under abnormal conditions, such as emergency shutdown of the unit and failure of the extraction steam heating system, the desuperheating and pressure reduction bypass can be automatically started to reduce the temperature and pressure of the sub-medium pressure steam entering the turbine to perform work to a low-pressure steam with a pressure of 1.0MPa and a temperature of 230℃, and supply it to external network users. The desuperheating water regulating valve of the heating bypass desuperheating and pressure reduction device is automatically put into operation, and the temperature target value and rate are set; the electric valve of the sub-medium pressure heating bypass desuperheating and pressure reduction device is automatically put into operation, and the pressure target value and rate are set, and the #4 sintering waste heat to extraction steam heating electric valve is opened.

[0027] Compared with the prior art, the present invention has the following advantages: a method for controlling the full-process automatic operation of a steam turbine island, the entire control process is fully automated and easy to use. The full-process automatic operation strategy of the steam turbine of the present invention enables the steam turbine to start safely and efficiently in the shortest time during startup, and enables the steam turbine and its steam turbine auxiliary system to safely and reliably switch from the shutdown state to the power generation state, thereby achieving the best economic benefits; it shuts down safely and efficiently in the shortest time during shutdown, and enables the steam turbine and its steam turbine auxiliary system to safely and reliably switch from the power generation state to the shutdown state, thereby reducing unnecessary losses. The full-process automatic operation method of the steam turbine of the present invention realizes a one-button start and stop control strategy through automatic control, improves the automation level of the steam turbine, avoids losses caused by manual operation errors, and extends the operating life of the steam turbine. Compared with the prior art, the beneficial effects of the present invention are as follows:

[0028] 1) The present invention can realize the full-process automatic control of the steam turbine island from cold state to automatic load, without manual intervention, thus reducing the labor intensity of the operating personnel.

[0029] 2) The present invention can realize breakpoint control: breakpoint control is set in the system, and the entire startup process is divided into several relatively independent program segments, and each program segment completes the respective control content. With the breakpoint control method, each breakpoint is both interconnected and independent of each other. As long as the breakpoint conditions are met, each breakpoint can be executed independently and the breakpoint can be manually intervened.

[0030] 3) The present invention can realize full-automatic and semi-automatic: the system provides full-automatic mode and semi-automatic mode, and the two modes can be switched at any time. The full-automatic mode will automatically execute each step without pausing in the middle. The semi-automatic mode will automatically pause after each step is completed, allowing the user to manually check the status and determine whether to proceed to the next step.

[0031] 4) The present invention can be used on demand: when not in use, it does not affect the normal control of the unit, and can switch between manual and automatic control by the operator; the programming of DEH, ETS, and DCS systems has a good interface with the system, unified interface standards, and no disturbance in switching. The upper logic and lower functional blocks and equipment control are independently debugged and modified. Under the coordinated control of the system, each system can achieve the necessary mutual coordination function.

[0032] 5) The present invention can realize the overrun control capability: for example, automatic breakpoint selection and step-by-step operation of parallel systems; the system can be manually intervened, and the startup process is divided into overridable and non-overridable conditions. It can intervene in the overriding items that do not meet the conditions during the self-starting process of the steam turbine, and can intervene in the speed increase (load) rate within the safe allowable range.

[0033] 6) The present invention can realize automatic maintenance: according to the state of the unit, the actual speed is compared with the low and medium speed warm-up speeds, and finally the speed increase is completed.

[0034] When speed is increasing, trigger:

[0035] Thrust bearing temperature exceeds alarm value

[0036] Support bearing temperature exceeding alarm value

[0037] Exhaust steam temperature exceeds alarm value

[0038] Condenser pressure exceeds alarm value

[0039] The temperature difference between the upper and lower cylinder walls exceeds the alarm value

[0040] The temperature difference between the inner and outer walls of the flange exceeds the alarm value

[0041] The metal temperature rise rate of the front cylinder inner wall exceeds the alarm value

[0042] The metal temperature rise rate of the reheat inlet chamber wall exceeds the alarm value

[0043] Expansion difference exceeds alarm value

[0044] Axial displacement exceeds alarm value

[0045] Axis vibration > alarm value

[0046] Lubricating oil pressure exceeds alarm value

[0047] The normal value of oil return from the bearing box exceeds the alarm value

[0048] Fuel tank level exceeds alarm value

[0049] Unit stress maintenance

[0050] At any time, the speed is maintained, and when none of the above conditions are met, the speed continues to increase.

[0051] 7) The present invention can achieve boundary control: one-touch control of the steam turbine generator set from the main steam bypass system to the stage of warming up the pipes to 50% of the rated load, automatic operation function and automatic operation control management, automatic periodic testing, automatic diagnosis of basic turbine faults, emergency accident processing and safe automatic control of the steam turbine under special working conditions such as "shutdown without stopping the furnace", while meeting the automatic operation of the turbine part (including automatic paralleling and decoupling of the main steam system).

[0052] 8) The present invention can realize adaptive change of shutdown protection value: when TSI speed is within the critical speed range of turbine (1300rpm to 1800rpm), the shaft vibration protection shutdown value is doubled from 125um to 200um, and automatically restored to the original shutdown setting value of 125um in the non-critical area. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 : Schematic diagram of the steam turbine island startup inspection process;

[0054] Figure 2 : Schematic diagram of the startup sequence of the auxiliary equipment of the steam turbine island;

[0055] Figure 3 : Schematic diagram of circulating water system of steam turbine island;

[0056] Figure 4 : Schematic diagram of the steam turbine island deaerator system;

[0057] Figure 5 : Schematic diagram of the condensate system of the steam turbine island;

[0058] Figure 6 : Schematic diagram of the lubricating oil system of the steam turbine island;

[0059] Figure 7 : Schematic diagram of turbine island turning system;

[0060] Figure 8 : Schematic diagram of steam turbine island regulation system;

[0061] Fig. 9 : Schematic diagram of turbine island bypass heating pipe system;

[0062] Fig.10 : Schematic diagram of the turbine island vacuum system;

[0063] Fig.11 : Schematic diagram of the turbine island shaft seal system;

[0064] Fig.12 : Schematic diagram of the turbine island speed-up sequence process;

[0065] Fig.13 : Schematic diagram of the turbine island grid connection sequence process;

[0066] Fig.14 : Schematic diagram of the turbine island load increase sequence process. DETAILED DESCRIPTION

[0067] In order to deepen the understanding of the present invention, the present embodiment is described in detail below with reference to the accompanying drawings.

[0068] Embodiment 1: The present invention provides a method for controlling the full-process automatic operation of a steam turbine island, the basic steps of which include:

[0069] Step 1. Start the inspection, such as Figure 1As shown in the figure, the startup inspection includes the inspection of various steam turbine auxiliary systems: deaerator system, condensate system, lubricating oil system, turning gear, EH oil, shaft seal system, vacuum system, valve inspection, instrument inspection, circulating water system inspection, initialization of sequential control system, and detection of corresponding parameters. Before starting, it is necessary to start the auxiliary system equipment and the auxiliary machine automatic test. Before starting, the steam quality judgment before the steam turbine is started can be realized and the automatic warm valve inspection can be performed; at the same time, the steam turbine can be reset when the conditions are met.

[0070] Step 2. Auxiliary machine start-up sequence,

[0071] The general sequence of auxiliary engine startup is as follows: Figure 2 Shown

[0072] 2.1 Unit status judgment: According to the starting procedures of this type of steam turbine, the starting status of the unit is automatically judged through program control: there are 4 starting modes: cold, warm, hot and extremely hot. For steam turbines, it is determined by the temperature of the upper metal (inner wall) of the high-pressure front cylinder.

[0073] 2.2 Circulating water system startup sequence: Figure 3 As shown, this step is to check the sequential control mode of circulating water inlet and outlet electric valves, circulating pump inverter, circulating pump high-voltage switch cabinet and other equipment. The circulating pump outlet butterfly valve is closed, the circulating pump inlet electric door and circulating pump outlet electric door are opened, KM3 is opened, KM1, KM2, and high-voltage switch cabinet are closed, the circulating water pump inverter is started, and the frequency is automatically increased. After the operating frequency is reached, KM3 is closed, KM1, KM2 are opened, and the standby pump interlock protection is put into operation; the normal operation of the circulating water system is realized.

[0074] 2.3 Deaeration system startup sequence: Figure 4 As shown, this step checks the allowed sequential control mode of the electric valves related to the deaerator system; the deaerator water replenishment protection interlock is automatically put into operation, the deaerator emergency drainage electric valve interlock is automatically put into operation, and the deaerator liquid level and pressure are automatically put into operation. When the load of the standby unit is greater than 5MW, the secondary pumping to deaerator electric valve and the secondary pumping to deaerator check valve are put into operation.

[0075] 2.4 Condensate start-up sequence: Figure 5 As shown, this step is to check the condensate pump outlet electric valve, condenser cooling water inlet and outlet electric doors, condensate pump recirculation valve, condensate pump and other equipment in the allowed sequential control mode. Open the condensate pump recirculation valve, the electric gate valve in front of the condensate feed water regulating valve, the condensate feed water regulating valve is put into automatic mode, and the condensate main pipe pressure is set to 0.6MPa to achieve the normal operation of the condensate pump to the deaerator feed water circuit, put into the pump valve interlock of the condensate pump outlet electric valve, start the condensate pump and put it into automatic mode, set the given target value, and put the standby pump interlock protection into place.

[0076] 2.5 Lubricating oil system startup sequence: Figure 6As shown, this step performs AC lubricating oil pump inspection, allows sequential control mode inspection, performs smoke exhaust fan operation inspection, starts the smoke exhaust fan and lubricating oil pump, and activates standby pump interlock protection.

[0077] 2.6 Crank start sequence: Figure 7 As shown, this step performs a check on the cranking permission sequential control mode; performs a pre-start check, including whether the oil pressure is normal, whether the main shaft speed is 0rpm, whether the cranking control box is remotely controlled, etc.; and starts the cranking equipment.

[0078] 2.7 Steam turbine regulation system steps: Figure 8 As shown, this step performs an EH oil pump sequential control mode check; when the EH oil temperature is greater than 20° and less than 60°, and the oil pressure is greater than 16MPa and less than 11.2MPa, start the EH oil pump; perform ETS braking, ETS reset, and ETS locking, and then perform ETS braking, ETS reset, and ETS locking; perform valve pulling and medium and high adjustment valve switching experiments to ensure that the steam turbine regulation can operate normally.

[0079] 2.8 Bypass pipe warming steps: Fig. 9 As shown, this step is to check the sequential control mode of the drain, cooling water and other valves; open the first-level drain valve: the drain valve in front of the electric door of the main steam mother pipe on the furnace side, and the drain valve in front of the high-pressure bypass; when the high-pressure bypass inlet pressure reaches 0.1MPa, open the minimum valve position control of the high and low bypass regulating valves.

[0080] 2.9 Vacuum start-up sequence: Fig.10 As shown, this step checks the condenser vacuum water supply solenoid valve, condenser vacuum breaking electric valve, and vacuum pump to allow sequential control mode; checks whether the condenser cooling water inlet and outlet electric valves are open; starts the condenser vacuum water supply solenoid valve to supply water, and when the water level in the separator is above 75mm, closes the condenser vacuum breaking electric valve and starts the vacuum pump; starts the standby vacuum pump interlock protection; and starts the low-pressure cylinder water spray interlock protection.

[0081] 2.10 Shaft seal start-up sequence: Fig.11 As shown, this step checks the steam seal pipe drain control valve, shaft fan, etc. in the permitted sequential control mode; turns on the shaft fan, puts the steam seal pipe drain control valve interlock protection into operation, the pressure equalizing box exhaust to six-stage extraction steam regulating valve is automatically put into operation and sets the target given value, the pressure equalizing box exhaust electric regulating valve is automatically put into operation and sets the target given value, the pressure equalizing box auxiliary steam / main steam (auxiliary steam is selected for cold and warm states, and main steam is selected for hot and extremely hot states) regulating valve is automatically put into operation and sets the target given value, the pressure equalizing box water spray regulating valve is automatically put into operation and sets the target given value, and the high-pressure cylinder rear shaft seal leakage water spray regulating valve is automatically put into operation and sets the target given value.

[0082] Step 3: Speed-up sequence,

[0083] 3.1 As Fig.12 As shown, after the auxiliary engine is started, when the temperature before and after the main steam electric door matches (select the judgment conditions according to the unit status, the same below), the pressure before and after the main steam electric door matches, the superheat before and after the main steam electric door matches, the high-speed valve is closed, the EH oil system is normal, and the DEH system is normal, the unit can enter the speed increase sequence, and automatically select the initial warm-up target value, the speed increase rate and the warm-up time through the status judgment program, and then realize the rush, warm-up, and constant speed. Unit status judgment, automatic ETS reset by the operator, lock the main steam valve, prepare for the rush mode, allow the rush, drain the start side, friction check, low and medium speed warm-up (this step is automatically skipped in non-cold state), rated speed.

[0084] 3.2 Rated speed: Fig.12 As shown, the thermal stress of each main body component is monitored during the speed increase process; the margin of the cylinder body is calculated in real time. The allowable range of the lifting and lowering rate of the computer unit is calculated based on the thermal stress margin. When the calculated value of the thermal stress exceeds the allowable range, the starting speed of the unit needs to be changed. Then this module recalculates the rate of change of the speed and load based on the thermal stress margin, and sends an optimized starting speed request to the control system. The component only selects the cylinder inner cylinder, and the cylinder thermal stress calculation temporarily uses the cylinder inner wall. The smaller value of the rate of protection calculated based on the cold, warm, hot, and extremely hot state main engine recommended lifting rate and temperature margin is taken as the actual operation lifting rate.

[0085] Step 4. Grid connection sequence: Fig.13 As shown, the unit can automatically connect to the grid, automatically carry the initial load, and increase the load according to the operating parameter curve provided by the main engine manufacturer. The procedure for the steam turbine unit to connect to the grid is: closing the demagnetization switch, remote control magnetization, automatic synchronization of DEH, synchronization reset, synchronization power on, synchronization power on, select synchronization point #2, closing permission, synchronization start, and synchronization reset after connecting to the grid.

[0086] Step 5. Load increasing sequence: Fig.14 As shown in the figure, the task of controlling the steam turbine generator from the initial load until the target load is reached. The target load can be given by the operator or specified in advance by other means. The controlled load change rate takes the lowest value of the following three change rates: the load change rate determined by stress changes; the load change rate given by the operator based on various reasons, including the operating conditions of other equipment in the power plant; the load change rate given by the DCS system. The system can automatically change the load change rate and generate load maintenance according to the current operating status of the unit. During load control, the system continuously monitors changes in turbine dynamic parameters such as pressure, temperature, thermal stress, vibration, expansion, etc., and alarms when the limit is exceeded, and generates maintenance or shutdown when necessary.

[0087] Step 6. Automatic shutdown: It is necessary to check the drain system interlock, deaerator, condensate, and shaft seal system. Put the bypass into automatic setting of main steam pressure and reheat steam pressure. Before load reduction, the operation mode is changed to power control mode. The axial displacement and expansion difference of the unit body are monitored throughout the load reduction process. If they are too large, the load reduction is suspended. After the load drops to 0, the operation mode determines whether the unit is shut down. After the shutdown speed drops to 0, the cranking is started, and other auxiliary systems remain in working condition.

[0088] Step 7: Automatic bypass operation under abnormal conditions: Under abnormal conditions, such as emergency shutdown of the unit and failure of the extraction steam heating system, the desuperheating and pressure reduction bypass can be automatically started to reduce the temperature and pressure of the sub-medium pressure steam entering the turbine to perform work to a low-pressure steam with a pressure of 1.0MPa and a temperature of 230℃, and supply it to external network users. The desuperheating water regulating valve of the heating bypass desuperheating and pressure reduction device is automatically put into operation, and the temperature target value and rate are set; the electric valve of the sub-medium pressure heating bypass desuperheating and pressure reduction device is automatically put into operation, and the pressure target value and rate are set, and the #4 sintering waste heat to extraction steam heating electric valve is opened.

[0089] Example 2: Reference Figure 1 — Fig.14 , a full-process automatic operation control strategy for a sub-medium pressure steam turbine island, the control method is as follows: Take the Meishan Iron and Steel sintering 2# waste heat steam turbine generator set as an example, which is a 15MW, extraction condensing, sub-medium pressure, double-pressure steam supplement, single exhaust type. The main steam pressure before the machine is 2.1MPa and the temperature is 350℃. It needs to be adjusted to the extraction pressure of 1.0MPa and the temperature is not lower than 230℃.

[0090] The present invention provides a method for full-process automatic operation of a steam turbine island, including: based on the operation specifications of each operation step of the startup process or shutdown process of the steam turbine island, the automatic interlocking of the steam turbine control system, the steam turbine auxiliary system, the steam turbine control system formulates each operation step of the startup process or shutdown process; in each operation step of the startup process or shutdown process, the steam turbine control system automatically issues an action instruction to the steam turbine auxiliary system corresponding to the current operation step, the steam turbine auxiliary system performs the corresponding action after receiving the action instruction and feeds back the current state to the steam turbine control system, the steam turbine control system automatically obtains and determines whether the current state of the steam turbine auxiliary system meets the prerequisite for executing the next operation step, if it meets the prerequisite, then executes the next operation step until the entire startup process or shutdown process is completed. The specific steps are:

[0091] Check the control systems of the steam turbine island: ATC, DCS, DEH, ETS, TSI power supply, electrical communication, CPU heartbeat; new steam pressure, temperature channel quality, electric valve self-inspection of the steam turbine steam-water system; turbine body speed, power, vibration, axial displacement, relative expansion channel quality, cylinder metal temperature channel quality, steam inlet speed valve closing, main steam drain system equipment self-inspection; circulating water system, condensate system, lubricating oil system, steam turbine regulating system, vacuum system, shaft seal and heating pipe system corresponding measuring point channel quality and equipment included in the system for self-inspection before startup.

[0092] If all the above self-tests are normal, the next step will be triggered. If there is a breakpoint, manual confirmation is required to continue executing the auxiliary machine start command. If there is no breakpoint, the auxiliary machine start command will be executed directly.

[0093] Detect the metal temperature (cylinder temperature, etc.) of the main components of the steam turbine, determine the metal temperature of the main components and lock the current unit status. After the unit status is locked, the circulating water system, condensate system, and deaeration system are triggered to start.

[0094] The start-up conditions of the circulating water system are as follows: the liquid level of the circulating cooling water well is greater than 4000m, the motor bearing temperature is less than 80°C, and the bearing temperature is less than 70°C.

[0095] If the start-up conditions are met, the next operation step is executed: the electric door of the condenser cooling water inlet and outlet is 30-50%;

[0096] If the feedback meets the conditions, the next operation step is executed: the circulating water pump outlet butterfly valve is closed;

[0097] If the feedback meets the conditions, the next operation step is executed: the circulation pump valve is interlocked;

[0098] If the feedback meets the conditions, the next operation step is executed: open the circulating pump inlet electric valve;

[0099] If the feedback meets the conditions, the next operation step is executed: open the circulating water pump outlet electric door;

[0100] If the feedback meets the conditions, the next operation step is executed: the inverter frequency is set to 10HZ;

[0101] If the feedback meets the conditions, the next operation step is executed: start the circulating water pump inverter;

[0102] If the feedback meets the conditions, the next operation step is executed: the inverter frequency is increased;

[0103] If the feedback meets the conditions, the next operation step is executed: standby pump interlock;

[0104] The completion conditions of the circulating water system are that the normal water level of the circulating water forepool is about 6000mm; the circulating water pump operates normally; the circulating water main pipe pressure is normal (>0.2Mpa); the condenser circulating cooling water return pressure is >0.08Mpa (normal 0.09).

[0105] The starting condition of the condensate system is that the water level in the desalted water tank is above 4 meters.

[0106] If the start-up conditions are not met, the next operation step is executed: the desalted water supply condenser valve interlock is put into operation, and water is automatically supplied;

[0107] If the feedback meets the conditions, the next operation step is executed: open the electric doors on the left and right sides of the condenser cooling water inlet and outlet for inspection;

[0108] If the feedback meets the conditions, the next operation step is executed: open the condensate recirculation door by 30%;

[0109] If the feedback meets the conditions, the next operation step is executed: the condensate pump valve interlock is activated;

[0110] If the feedback meets the conditions, the next operation step is executed: start the condensate pump;

[0111] If the feedback meets the conditions, the next operation step is executed: the condensate pump is automatically activated;

[0112] If the feedback meets the conditions, the next operation step is executed: setting the automatic target of the liquid level;

[0113] If the feedback meets the conditions, the next operation step is executed: open the electric gate valve of the condensate deaerator;

[0114] If the feedback meets the conditions, the next operation step is executed: the condensate water upper water regulating door is automatically set;

[0115] If the feedback meets the conditions, the next operation step is executed: interlock the standby pump;

[0116] The completion conditions of the condensate system are: 1 or 2 condensate pumps are running; 1 or 2 interlocks are put into operation; the condensate pump outlet electric valve is open; the condensate pump outlet main pipe pressure is normal (greater than 1.17MPa); the electric valve in front of the condensate supply regulating valve is open; the condensate pump inverter is automatic; the condensate supply regulating valve is automatic (deaerator); the make-up water regulating valve is fully closed (desalted water); the recirculation regulating valve is automatic.

[0117] The deaerator system starts when the water quality is qualified after the conductivity meter detects

[0118] If the startup conditions are met, the next operation step is executed: deaerator water replenishment protection interlock;

[0119] If the feedback meets the conditions, the next operation step is executed: deaerator drainage protection interlock;

[0120] If the feedback meets the conditions, the next operation step is executed: automatic deoxygenation level is added;

[0121] If the feedback meets the conditions, the next operation step is executed: the deaerator pressure regulating valve is automatically put into operation;

[0122] If the feedback meets the conditions, the next operation step is executed: the extraction steam interlock is activated;

[0123] The completion conditions of the deaerator system are that the deaerator liquid level regulation has been put into operation (deionized water enters the deaerator regulating valve); the deaerator pressure regulating valve has been put into automatic operation; the deaerator water level is about 2000mm; and the deaerator pressure is about 0.7-0.9MPa.

[0124] The vacuum system is triggered after the circulating water system, condensate water system and deaeration system are started up.

[0125] The vacuum system startup condition is cold or hot & the pressure of the pressure equalizing box is >10kPa

[0126] If the start-up conditions are met, the next operation step is executed: separator water replenishment;

[0127] If the feedback meets the conditions, the next operation step is executed: closing the vacuum breaking electric valve;

[0128] If the feedback meets the conditions, the next operation step is executed: start the vacuum pump;

[0129] If the feedback meets the conditions, the next operation step is executed: water injection interlock of the rear cylinder;

[0130] If the feedback meets the conditions, the next operation step is executed: vacuum pump interlock preparation;

[0131] The completion conditions of the vacuum system are that any vacuum pump is running; the vacuum breaking door is closed; the rear cylinder water spray regulating valve is put into automatic mode; the corresponding vacuum pump inlet pneumatic valve is opened; the vacuum pump standby interlock is on; and the vacuum is <-40kPa.

[0132] After the vacuum system is started, the lubricating oil system and regulating oil system are triggered.

[0133] The lubricating oil system startup condition is -480mm<oil level<650mm

[0134] If the start condition is met, the next operation step is executed: start the smoke exhaust fan;

[0135] If the feedback meets the conditions, the next operation step is executed: start the AC oil pump;

[0136] If the feedback meets the conditions, the next operation step is executed: AC lubricating oil pump interlock is activated;

[0137] If the feedback meets the condition, execute the next operation step: engage the DC lubricating oil pump interlock;

[0138] If the feedback meets the condition, execute the next operation step: engage the turning gear;

[0139] The completion conditions for the lubricating oil system are normal oil pressure (0.15 - 0.17 MPa); the temperature of the outlet header pipe of the oil cooler: 35 - 48 °C; normal bearing inlet oil; normal bearing box return oil; normal differential pressure of the duplex filter.

[0140] The starting conditions for the governing oil system are normal oil level (below 400 mm & above 300 mm); the pressure in front of the main steam valve < 0.1 MPa; the main steam stop valve is fully closed; the EH oil pressure < 14.5 MPa;

[0141] If the starting conditions are met, execute the next operation step: engage the EH circulating cooling pump interlock;

[0142] If the feedback meets the condition, execute the next operation step: engage the EH heater interlock;

[0143] If the feedback meets the condition, execute the next operation step: start the EH oil pump and engage the standby pump;

[0144] If the feedback meets the condition, execute the next operation step: trip the ETS;

[0145] If the feedback meets the condition, execute the next operation step: reset the ETS;

[0146] If the feedback meets the condition, execute the next operation step: engage the governor valve;

[0147] If the feedback meets the condition, execute the next operation step: engage the extraction valve;

[0148] If the feedback meets the condition, execute the next operation step: disengage the extraction valve;

[0149] The completion conditions for the governing oil system are 300 < EH oil tank liquid level < 400; 11.2 < EH oil pressure < 16; 20 < EH oil temperature < 50; EH oil pump running indication.

[0150] After the lubricating oil system and the governing oil system are started and completed, trigger the bypass warm-up, the main steam stop valve warm-up, and the shaft seal system.

[0151] The starting condition for the bypass warm-up is that the vacuum reaches -60 kPa

[0152] If the starting conditions are met, execute the next operation step: open the first-stage drain and equipment compliance;

[0153] If the feedback meets the condition, execute the next operation step: open the second-stage drain;

[0154] If the feedback meets the conditions, the next operation step is executed: open the third-level drain;

[0155] If the feedback meets the conditions, the next operation step is executed: DC lubricating oil pump interlock is activated;

[0156] If the feedback meets the conditions, the next operation step is executed: the disk car is put into operation;

[0157] The bypass pipe heating is completed when the bypass system is in automatic mode and the steam trap is in the open state.

[0158] The starting conditions for the electric main steam valve warm-up pipe are: main steam pressure before the electric valve > 2MPa; main steam superheat > 80℃; reheat steam pressure > 0.5MPa; reheat steam superheat > 80℃.

[0159] If the start-up conditions are met, the next operation step is executed: cold-open the electric main steam valve bypass stop valve;

[0160] If the feedback meets the conditions, the next operation step is executed: cold open the bypass regulating valve of the electric main steam valve and drain the water after the electric main steam valve;

[0161] If the feedback meets the conditions, the next operation step is executed: open the electric main steam valve, close the bypass stop valve and bypass regulating valve;

[0162] The conditions for completing the electric main steam valve pipe heating are that the drain is open and the steam temperature, pressure and superheat are met.

[0163] The starting conditions of the shaft seal system are cold: the vacuum pump is started; the temperature in front of the main steam electric door is >160℃

[0164] Non-cold state: the temperature before the main steam valve - the temperature of the upper inner wall of the high-pressure cylinder>80; the steam superheat degree of the temperature before the main steam valve is met.

[0165] If the start condition is met, the next operation step is executed: start the shaft plus fan;

[0166] If the feedback meets the conditions, the next operation step is executed: open the steam seal pipeline to drain water;

[0167] If the feedback meets the conditions, the next operation step is executed: the pressure equalizing tank leaks steam to the sixth-stage steam extraction regulating valve to be put into automatic operation;

[0168] If the feedback meets the conditions, the next operation step is executed: the steam inlet regulating valve of the pressure equalizing tank is put into automatic operation;

[0169] If the feedback meets the conditions, the next operation step is executed: the pressure equalizing tank desuperheating water is automatically added;

[0170] If the feedback meets the conditions, the next operation step is executed: the low-pressure cylinder rear shaft seal spray water regulating valve is automatically put into operation;

[0171] The completion conditions of the shaft sealing system are that any shaft sealing fan is in operation; the temperature reducing water regulating valve of the pressure equalizing box is automatically put into operation, and the interlocking of the pressure equalizing box exhaust to the sixth-stage extraction steam regulating valve is put into operation; the steam inlet regulating valve of the pressure equalizing box is automatically put into operation; 160℃<pressure equalizing box temperature<220℃; 0.105<pressure equalizing box pressure<0.118MPa(a); the water level of the shaft is about 150-280mm; normal operation is 365mm.

[0172] After the auxiliary system is started, the host speed increase is triggered. If there is a breakpoint, manual confirmation is required to continue executing the host speed increase command. If there is no breakpoint, the host speed increase is executed directly.

[0173] Detect the metal temperature of the main components of the steam turbine and the steam inlet parameters (such as the steam inlet temperature), and determine whether the metal temperature of the main components and the steam inlet parameters match each other. If they match, execute the next operation step: before and during the start-up, the steam turbine control system preheats the main components that need to be preheated to the warm-up level; the steam turbine control system automatically determines one or more of the turbine's ramp-up rate, target speed, and load increase rate based on the thermal stress of the main components: such operation can ensure that the thermal stress of the steam turbine during the startup process is minimized. Further, the above-mentioned shutdown process includes the following steps: automatically determine one or more of the turbine's ramp-down rate, target speed, and load deceleration based on the thermal stress of the main components of the steam turbine. Such operation can ensure that the thermal stress of the steam turbine during the shutdown process is minimized.

[0174] During the speed increase process, if any of the following conditions is triggered, the speed will be automatically maintained;

[0175] Thrust bearing temperature>100°

[0176] Support bearing temperature>100°

[0177] Exhaust steam temperature>80°

[0178] Condenser pressure>-86.6kPa

[0179] Temperature difference between the upper and lower cylinder walls>50°

[0180] Temperature difference between inner and outer walls of flange>50°

[0181] The metal temperature rise rate of the front cylinder inner wall>2℃ / min

[0182] Reheat inlet chamber inner wall metal temperature rise rate>2℃ / min

[0183] Expansion difference <-2mm or >3mm

[0184] Axial displacement exceeds <-0.8mm or >0.3mm

[0185] Shaft vibration>80um

[0186] Lubricating oil pressure <40° or >50°

[0187] Normal value of oil return from bearing box>70°

[0188] Fuel tank level <-450mm or >650mm

[0189] Unit stress maintenance

[0190] During the speed increase process, when the TSI speed is within the critical speed range of the turbine (1300rpm to 1800rpm), the shaft vibration protection shutdown value is doubled from 125um to 200um, and automatically returns to the original shutdown setting value of 125um in the non-critical area, achieving automatic doubling.

[0191] After the host speed increase is completed, the electrical grid connection is triggered. If there is a breakpoint, manual confirmation is required to continue executing the electrical grid connection instruction. If there is no breakpoint, the electrical grid connection is executed directly.

[0192] The electrical grid-connected startup condition is stable operation at rated speed

[0193] If the start condition is met, the next operation step is executed: the demagnetization switch is closed;

[0194] If the feedback meets the conditions, the next operation step is executed: remote control magnetization input;

[0195] If the feedback meets the conditions, the next operation step is executed: DEH is put into automatic synchronization;

[0196] If the feedback meets the conditions, the next operation step is executed: synchronous reset;

[0197] If the feedback meets the conditions, the next operation step is executed: synchronous power-on;

[0198] If the feedback meets the conditions, the next operation step is executed: select the synchronization point;

[0199] If the feedback meets the conditions, the next operation step is executed: closing is allowed;

[0200] If the feedback meets the conditions, the next operation step is executed: synchronous start;

[0201] If the feedback meets the conditions, the next operation step is executed: synchronous reset after grid connection;

[0202] The condition for electrical grid connection is that the generator is connected to the grid and operates.

[0203] After the electrical grid connection is completed, the automatic load is triggered. If there is a breakpoint, manual confirmation is required to continue executing the automatic load instruction. If there is no breakpoint, the automatic load is executed directly.

[0204] After the automatic load increase command is confirmed, the unit status is judged;

[0205] If the feedback meets the conditions, the next operation step is executed: the drain interlock is activated and the water spray cooling interlock is activated;

[0206] If the feedback meets the conditions, the next operation step is executed: DEH is put into pressure control, the bypass is switched to manual control, the unit enters the bypass load increase mode, the bypass valve position is in control mode, pressure control is put into operation, and the target value is set (the initial target value tracks the current pressure). At the same time, the 5% lower limit of the high bypass is released, and the 15% lower limit of the low bypass is set.

[0207] If the feedback meets the conditions, the next operation step is executed: bypass load increase control mode. The unit status is judged. If all execution conditions are OK, the bypass load increase mode is continued.

[0208] If the feedback meets the conditions, the next operation step is executed: when the unit load reaches 50% of the rated load, the bypass load increase control mode is exited, the high and low bypass are automatically put into operation (enter the follow-up mode), and the high and low bypass control lower limits are set to 0%.

[0209] If the feedback meets the conditions, the next operation step is executed: DEH enters the pressure automatic control mode or power automatic control mode.

[0210] The main control program judges the unit operating conditions and executes the shutdown sequence when the conditions are met;

[0211] Automatic input power control;

[0212] If the feedback meets the conditions, the next operation step is executed: the load drops to 30%

[0213] If the feedback meets the conditions, the next operation step is executed: if heat is supplied to the outside, the heat bypass is activated to reduce the temperature and pressure, and then the steam extraction control is exited; if heat is not supplied to the outside, the steam extraction control is exited.

[0214] If the feedback meets the conditions, the next operation step is executed: the turbine load drops to 5% of the initial load

[0215] If the feedback meets the conditions, the next operation step is executed: drain

[0216] If the feedback meets the conditions, the next operation step is executed: cranking interlock is enabled

[0217] If the feedback meets the conditions, the next operation step is executed: trigger ETS shutdown (manual)

[0218] If the feedback meets the conditions, the next operation step is executed: Waiting for the cranking to start

[0219] The main control program judges the unit operating conditions and executes the bypass automatic operation sequence when the conditions are met;

[0220] The desuperheating water regulating valve of the heating bypass desuperheating and pressure reducing device is put into automatic operation;

[0221] If the feedback meets the conditions, the next operation step is executed: setting the temperature target value and rate;

[0222] If the feedback meets the conditions, the next operation step is executed: the medium-pressure heating bypass temperature and pressure reducer electric valve is automatically put into operation;

[0223] If the feedback meets the conditions, the next operation step is executed: set the pressure target value and rate, and open the #4 sintering waste heat to steam extraction heating electric valve.

[0224] It should be noted that the above embodiments are not intended to limit the protection scope of the present invention, and equivalent changes or substitutions made on the basis of the above technical solutions all fall within the protection scope of the claims of the present invention.

Claims

1. A full-process automatic operation control method for a secondary medium pressure steam turbine island, characterized in that: The method comprises the following steps: Step 1: Start the inspection, Step 2: Auxiliary machine start-up sequence, Step 3: Speed-up sequence, Step 4: Grid connection sequence, Step 5: Load increasing sequence, Step 6: Automatic shutdown, Step 7: Automatic bypass operation under abnormal conditions.

2. The full-process automatic operation control method of a secondary medium pressure steam turbine island according to claim 1 is characterized in that: The step 1: startup inspection is as follows. The startup inspection includes the inspection of various steam turbine auxiliary systems: deaerator system, condensate system, lubricating oil system, turning gear, EH oil, shaft seal system, vacuum system, valve inspection, instrument inspection, circulating water system inspection, and sequential control system initialization. At the same time, the corresponding parameters are detected. Before starting, the auxiliary system equipment and auxiliary machine automatic test need to be started. Before starting, the steam quality judgment before the turbine is started can be realized and the automatic warm-up valve inspection can be performed; at the same time, the steam turbine is reset when the conditions are met.

3. The full-process automatic operation control method of a secondary medium pressure steam turbine island according to claim 1 is characterized in that: Step 2: Auxiliary machine startup sequence, as follows: 2.1 Unit status judgment: According to the starting procedures of this type of steam turbine, the starting status of the unit is automatically judged through program control: there are 4 starting modes: cold, warm, hot and extremely hot. For steam turbines, it is determined by the upper metal (inner wall) temperature of the high-pressure front cylinder. 2.2 The starting sequence of the circulating water system is to check the sequential control mode of the circulating water inlet and outlet electric valves, circulating pump frequency converter, circulating pump high-voltage switch cabinet and other equipment. The circulating pump outlet butterfly valve is closed, the circulating pump inlet electric door and circulating pump outlet electric door are opened, KM3 is opened, KM1, KM2 and high-voltage switch cabinet are closed, the circulating water pump frequency converter is started, and the frequency is automatically increased. After the operating frequency is reached, KM3 is closed, KM1 and KM2 are opened, and the standby pump interlock protection is put into operation; the normal operation of the circulating water system is realized. 2.3 Deaerator system startup sequence, this sequence is to check the allowed sequential control mode of the electric valves related to the deaerator system, the deaerator water replenishment protection interlock is automatically put into operation, the deaerator emergency drainage electric valve interlock is automatically put into operation, the deaerator liquid level and pressure are automatically put into operation, and the unit load is greater than 5MW, and the secondary pumping to the deaerator electric valve and the secondary pumping to the deaerator check valve are put into operation. 2.4 Condensate start-up sequence, this step is to check the condensate pump outlet electric valve, condenser cooling water inlet and outlet electric doors, condensate pump recirculation valve, condensate pump and other equipment to allow sequential control mode, open the condensate pump recirculation valve, the electric gate valve in front of the condensate water supply regulating valve, the condensate water supply regulating valve is put into automatic mode, set the condensate main pipe pressure to 0.6MPa, realize the normal operation of the condensate pump to the deaerator water supply circuit, put into the condensate pump outlet electric valve pump valve interlock, and start the condensate pump and put it into automatic mode, set the given target value, put the standby pump interlock protection into operation, 2.5 Lubricating oil system startup sequence, this sequence starts the AC lubricating oil pump, allows the sequential control mode to be checked; performs the exhaust fan operation check; starts the exhaust fan and lubricating oil pump, and puts the standby pump into interlock protection, 2.6 Cranking start sequence, this sequence is to check the cranking permission sequential control mode; to check before starting, including whether the oil pressure is normal, whether the main shaft speed is 0rpm, whether the cranking control box is remote control, etc.; to start the cranking equipment, 2.7 Steam turbine regulation system sequence, this sequence is to check the EH oil pump for the allowed sequential control mode; when the EH oil temperature is greater than 20° and less than 60°, and the oil pressure is greater than 16MPa and less than 11.2MPa, start the EH oil pump; perform ETS brake, ETS reset, lock, and then perform ETS brake, ETS reset, lock; perform valve pulling, and medium and high adjustment valve opening and closing experiments to ensure that the steam turbine regulation can operate normally. 2.8 Bypass pipe warming sub-sequence, this step is to check the valves such as drain and cooling water to allow the sequential control mode; open the first-level drain valve: the drain valve in front of the electric door of the main steam mother pipe on the furnace side, and the drain valve in front of the high-pressure bypass; wait for the high-pressure bypass inlet pressure to reach 0.1MPa, open the minimum valve position control of the high and low bypass regulating valves, 2.9 Vacuum start sequence, this step is to check the condenser vacuum water supply solenoid valve, condenser vacuum breaking electric valve, and vacuum pump to allow sequential control mode; check whether the condenser cooling water inlet and outlet electric valve is open; start the condenser vacuum water supply solenoid valve to supply water, the separator water level is above 75mm, close the condenser vacuum breaking electric valve, and start the vacuum pump; the standby vacuum pump interlock protection is activated; the low-pressure cylinder water spray interlock protection is activated, 2.10 Shaft seal start-up sequence: As shown in Figure 11, this step checks the steam seal pipe drain control valve, shaft fan, etc. in the allowed sequential control mode; turns on the shaft fan, the steam seal pipe drain control valve interlock protection is activated, the pressure equalizing box exhaust to six-stage extraction steam regulating valve is automatically activated and the target given value is set, the pressure equalizing box exhaust electric regulating valve is automatically activated and the target given value is set, the pressure equalizing box auxiliary steam / main steam (auxiliary steam is selected for cold and warm states, and main steam is selected for hot and extremely hot states) regulating valve is automatically activated and the target given value is set, the pressure equalizing box water spray regulating valve is automatically activated and the target given value is set, the high-pressure cylinder rear shaft seal leakage water spray regulating valve is automatically activated and the target given value is set.

4. The full-process automatic operation control method of a secondary medium pressure steam turbine island according to claim 1 is characterized in that: Step 3: The speed-up sequence is as follows: 3.1, after the auxiliary engine is started, when the temperature before and after the main steam electric door matches (select the judgment conditions according to the unit status, the same below), the pressure before and after the main steam electric door matches, the superheat before and after the main steam electric door matches, the high-speed valve is closed, the EH oil system is normal, and the DEH system is normal, the unit can enter the speed increase sequence, and the program control automatically selects the initial warm-up target value, the speed increase rate and the warm-up time through the status judgment, and then realizes the rush, warm-up, constant speed, unit status judgment, operator automatic ETS reset, lock the main steam valve, rush mode preparation, allow rush, start-up side drainage, friction check, low and medium speed warm-up (this step is automatically skipped in non-cold state), rated speed, 3.2 Rated speed: thermal stress monitoring of each main component during speed increase; real-time measurement and cylinder margin, computer unit speed increase and decrease rate allowable range based on thermal stress margin. When the calculated thermal stress value exceeds the allowable range and the starting speed of the unit needs to be changed, this module will recalculate the speed and load change rate based on the thermal stress margin, and send an optimized starting speed request to the control system. The component only selects the cylinder inner cylinder, and the cylinder thermal stress calculation tentatively uses the cylinder inner wall. The smaller value of the actual operating speed increase rate is taken according to the speed increase rate recommended by the main engine manufacturer in cold, warm, hot and extremely hot states and the temperature margin to calculate the protection rate.

5. The full-process automatic operation control method of a secondary medium pressure steam turbine island according to claim 1 is characterized in that: Step 4: Grid connection sequence, as follows: During the grid connection stage, the unit can automatically connect to the grid, automatically take on the initial load, and increase the load according to the operating parameter curve provided by the main engine manufacturer. The procedure for the steam turbine unit to connect to the grid is: closing the demagnetization switch, remote control magnetization, automatic synchronization of DEH, synchronization reset, synchronization power-on, synchronization power-on, selection of synchronization point #2, closing permission, synchronization start, and synchronization reset after grid connection.

6. The full-process automatic operation control method of a secondary medium pressure steam turbine island according to claim 1 is characterized in that: Step 5: Load increase sequence, as follows: Control the steam turbine generator from the initial load until the target load is reached. The target load can be given by the operator or specified in advance by other means. The controlled load change rate takes the lowest value of the following three change rates: the load change rate determined by stress change; the load change rate given by the operator based on various reasons, including the operating conditions of other equipment in the power plant; the load change rate given by the DCS system. The system can automatically change the load change rate and generate load holding according to the current operating status of the unit. During load control, the system continuously monitors changes in dynamic parameters of the steam turbine such as pressure, temperature, thermal stress, vibration, expansion, etc., and alarms when the limit is exceeded, and generates holding or shutdown when necessary.

7. The full-process automatic operation control method of a secondary medium pressure steam turbine island according to claim 1 is characterized in that: Step 6: Automatic shutdown. Specifically, it is necessary to check the drain system interlock, deaerator, condensate, and shaft seal system. The bypass is put into automatic setting of the main steam pressure and reheat steam pressure. The operation mode is changed to power control mode before load reduction. The axial displacement and expansion difference of the unit body are monitored throughout the load reduction process. If they are too large, the load reduction is suspended. After the load drops to 0, the operation mode determines whether the unit is shut down. After the shutdown speed drops to 0, the cranking is started, and other auxiliary systems remain in working condition.

8. The full-process automatic operation control method of a secondary medium pressure steam turbine island according to claim 1 is characterized in that: Step 7: The bypass automatically operates under abnormal operating conditions. Specifically, under abnormal operating conditions, emergency shutdown of the unit, and failure of the extraction steam heating system, the temperature reduction and pressure reduction bypass can be automatically started to reduce the temperature and pressure of the sub-medium pressure steam entering the turbine to perform work to a low-pressure steam with a pressure of 1.0 MPa and a temperature of 230°C, and supply it to external network users. The heating bypass temperature reduction and pressure reduction device temperature reduction water regulating valve is automatically started, and the temperature target value and rate are set; the sub-medium pressure heating bypass temperature reduction and pressure reduction device electric valve is automatically started, and the pressure target value and rate are set, and the #4 sintering waste heat to extraction steam heating electric valve is opened.

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