System, method and device for reducing thermal stress of steam turbine rotor under deep peak regulation working condition

Abstract

The invention provides a system, method and device for reducing thermal stress of a steam turbine rotor under the deep peak regulation working condition. The system comprises a steam turbine bypass system and a steam parameter adjusting pipeline connected with the steam turbine bypass system in parallel. A first steam parameter adjusting valve and a first peak shaving heat accumulator which are sequentially connected in series are arranged in the steam parameter adjusting pipeline. The steam extraction pipeline is led out from a main steam pipeline of the steam turbine bypass system; wherein a second steam parameter adjusting valve and a second peak regulation heat accumulator which are sequentially connected in series are arranged on the steam extraction pipeline; the fused salt heat storage system is connected with the peak regulation heat accumulator I and the peak regulation heat accumulator II; the controller is used for collecting system measuring point information through a signal cable and controlling the opening degree of the first steam parameter adjusting valve and the opening degree of the second steam parameter adjusting valve. The thermal stress borne by the steam turbine rotor under the deep peak regulation working condition can be reduced, and the safety risk caused by frequent thermal stress borne by the steam turbine rotor is reduced.

Description

Technical Field

[0001] The present application relates to the field of power plant operation and maintenance, and specifically to a system, method and device for reducing thermal stress of a steam turbine rotor under deep peak regulation conditions. Background Art

[0002] As deep peak load regulation becomes the normal operating condition of thermal power plants, thermal power plants currently have to go through one or more changes from deep peak load regulation to high load regulation every day. This operating condition is not the design condition of the unit. Under deep peak load regulation, parameters such as steam pressure and temperature are difficult to reach the rated values, which may cause many inestimable hazards to the turbine rotor, such as unit vibration problems and rotor fatigue damage.

[0003] Researching and developing effective monitoring or compensation optimization strategies, monitoring steam parameters in detail under deep peak-shaving conditions, obtaining rotor operating status in real time, stabilizing the temperature of reheated steam under deep peak-shaving conditions, reducing thermal stress of steam turbine rotors, and improving unit operation safety have become one of the important research topics for deep peak-shaving units. In recent years, rotor stress monitoring methods for low-load conditions have frequently emerged in order to monitor the rotor status in all directions and provide early warnings. However, existing solutions are mostly used to solve the vibration problem of the last-stage blades of the low-pressure cylinder, or the problem of uneven local thermal stress of the rotor under low-load conditions. However, there is no effective strategy for fatigue damage to the rotor caused by thermal stress under deep peak-shaving conditions.

[0004] This section is intended to provide a background or context to the embodiments of the invention recited in the claims. No admission is made that the description herein is prior art by inclusion in this section. Summary of the invention

[0005] In response to the problems in the prior art, the present application provides a system, method and device for reducing the thermal stress of a turbine rotor under deep peak-shaving conditions, which can reduce the thermal stress on the turbine rotor under deep peak-shaving conditions and reduce the safety risks caused by frequent thermal stress on the turbine rotor.

[0006] In order to solve the above technical problems, this application provides the following technical solutions:

[0007] In a first aspect, the present application provides a system for reducing thermal stress of a steam turbine rotor in deep peak load operation, comprising:

[0008] A steam turbine bypass system and a steam parameter adjustment pipeline arranged in parallel with the steam turbine bypass system; wherein the steam parameter adjustment pipeline is provided with a steam parameter regulating valve 1 and a peak regulation heat accumulator 1 connected in series in sequence;

[0009] A steam extraction pipeline is led out from the main steam pipeline of the turbine bypass system; wherein, on the steam extraction pipeline, a second steam parameter regulating valve and a second peak-shaving heat accumulator are arranged in series;

[0010] A molten salt heat storage system connected to the peak-shaving heat accumulator 1 and the peak-shaving heat accumulator 2;

[0011] The controller is used to collect system measurement point information through signal cables and control the opening of the steam parameter regulating valve 1 and the steam parameter regulating valve 2.

[0012] Furthermore, the molten salt heat storage system includes a molten salt heater, a cold salt pump, a hot salt pump, a low-temperature molten salt tank and a high-temperature molten salt tank; wherein the cold salt pump transports the low-temperature molten salt in the low-temperature molten salt tank to the peak-shaving heat accumulator 1 and the peak-shaving heat accumulator 2 for heat absorption and temperature rise; the high-temperature molten salt enters the high-temperature molten salt tank for storage, and when needed, the high-temperature molten salt is transported to the molten salt heater by the hot salt pump to heat the feed water, and then returned to the low-temperature molten salt tank to form a loop.

[0013] Furthermore, the turbine bypass system comprises:

[0014] Main steam valve;

[0015] A high-pressure cylinder, a medium-pressure cylinder and a low-pressure cylinder are arranged in series; wherein one end of the high-pressure cylinder is connected to the main steam valve;

[0016] A reheater having one end connected to the high-pressure cylinder and the other end connected to the medium-pressure cylinder and the steam parameter regulating valve;

[0017] A low bypass valve having one end connected to the steam parameter regulating valve;

[0018] A condenser having one end connected to the low pressure cylinder and the other end connected to the low bypass valve and the peak load accumulator;

[0019] Steam turbine fault monitoring system;

[0020] A superheater connected to the main steam valve and the steam parameter regulating valve 2.

[0021] Furthermore, the system measurement point information includes: main steam temperature, reheat steam temperature, main steam extraction flow rate, reheat extraction flow rate and turbine fault monitoring system alarm signal.

[0022] In a second aspect, the present application provides a method for reducing thermal stress of a steam turbine rotor under deep peak load operation, which is applied to the system for reducing thermal stress of a steam turbine rotor under deep peak load operation, comprising:

[0023] When the unit load enters the deep peak load condition, when it is detected that the temperature difference between the reheat steam temperature and the main steam temperature exceeds the first threshold, the steam parameter regulating valve 1 and the steam parameter regulating valve 2 are gradually opened to store part of the reheat steam heat in the molten salt heat storage system, maintain the reheat steam temperature, and reduce the thermal stress of the medium and low pressure rotors;

[0024] When it is detected that the unit load returns to the second threshold, the steam parameter regulating valve 1 and the steam parameter regulating valve 2 are controlled to be gradually closed to increase the steam parameters.

[0025] Further, when it is detected that the temperature difference between the reheat steam temperature and the main steam temperature exceeds the first threshold, the steam parameter regulating valve 1 and the steam parameter regulating valve 2 are gradually opened, including:

[0026] Determining whether the reheat steam temperature is lower than a set system input temperature, and whether the temperature difference between the reheat steam temperature and the main steam temperature exceeds the first threshold;

[0027] If so, control the start of the cold salt pump to output the molten salt in the low-temperature molten salt tank, and then heat it through the peak-shaving heat accumulator 1 and the peak-shaving heat accumulator 2 and then output it back to the high-temperature molten salt tank; and control the opening of the steam parameter regulating valve 1 and the steam parameter regulating valve 2; meanwhile, continuously collect the main steam extraction flow parameters and the reheat extraction flow parameters, and control the main steam extraction flow parameters to be consistent with the reheat extraction flow parameters to maintain the axial thrust balance of the turbine.

[0028] Furthermore, the method for reducing thermal stress of a steam turbine rotor in deep peak load regulation conditions further comprises:

[0029] In the process of gradually opening the steam parameter regulating valve 1 and the steam parameter regulating valve 2, the steam turbine fault monitoring system is continuously monitored to see whether an alarm signal is issued;

[0030] If so, suspend opening of steam parameter regulating valve 1 and steam parameter regulating valve 2 until the fault is eliminated, and continue to open steam parameter regulating valve 1 and steam parameter regulating valve 2 to increase the reheat steam temperature to the preset value and maintain it.

[0031] Further, when it is detected that the unit load returns to the second threshold, the steam parameter regulating valve 1 and the steam parameter regulating valve 2 are controlled to be gradually closed, including:

[0032] When it is detected that the load of the unit has returned to the second threshold, the steam parameter regulating valve 1 and the steam parameter regulating valve 2 are controlled to be gradually fully closed;

[0033] Start the hot salt pump to output the high-temperature molten salt in the high-temperature molten salt tank, and heat the feed water through the molten salt heater to increase the unit load. After the steam parameter regulating valve 1 and the steam parameter regulating valve 2 are all closed, stop the cold salt pump.

[0034] Furthermore, the method for reducing thermal stress of a steam turbine rotor in deep peak load regulation conditions further comprises:

[0035] When it is detected that the load of the unit continues to rise to more than 50%, it is determined that the deep peak load regulation condition is out of operation;

[0036] The hot salt pump is controlled to continue to operate until the liquid level in the high-temperature molten salt tank drops to a preset low liquid level.

[0037] In a third aspect, the present application provides a device for reducing thermal stress of a steam turbine rotor in a deep peak-shaving condition, which is applied to the system for reducing thermal stress of a steam turbine rotor in a deep peak-shaving condition, comprising:

[0038] The regulating valve opening unit is used to control the gradual opening of the steam parameter regulating valve 1 and the steam parameter regulating valve 2 when it is detected that the temperature difference between the reheat steam temperature and the main steam temperature exceeds the first threshold value after the unit load enters the deep peak regulation condition, so as to store part of the reheat steam heat in the molten salt heat storage system, maintain the reheat steam temperature, and reduce the thermal stress of the medium and low pressure rotors;

[0039] The regulating valve closing unit is used to control the gradual closing of the steam parameter regulating valve 1 and the steam parameter regulating valve 2 to increase the reheat steam temperature when it is detected that the unit load returns to the second threshold.

[0040] In a fourth aspect, the present application provides an electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the program, the steps of the method for reducing the thermal stress of a turbine rotor under deep peak-shaving conditions are implemented.

[0041] In a fifth aspect, the present application provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the method for reducing the thermal stress of a turbine rotor under deep peak-shaving conditions.

[0042] In a sixth aspect, the present application provides a computer program product, including a computer program / instruction, which, when executed by a processor, implements the steps of the method for reducing the thermal stress of a turbine rotor under deep peak-shaving conditions.

[0043] In response to the problems in the prior art, the system, method and device for reducing the thermal stress of the turbine rotor under deep peak-shaving conditions provided in the present application can achieve long-term stability of the reheat steam parameters under various conditions without affecting the electrical load of the unit through automatic control of the steam parameter regulating valve under full-load conditions, thereby reducing the thermal stress on the turbine rotor under deep peak-shaving conditions, greatly reducing the risk of unit non-stopping due to frequent alternating stress on the rotor, improving the reliability of unit operation under deep peak-shaving conditions, and better supporting the consumption of new energy. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0045] Figure 1 This is a structural diagram of a system for reducing thermal stress of a steam turbine rotor in deep peak load operation conditions in an embodiment of the present application;

[0046] Figure 2 This is one of the flow charts of the load reduction process control method of the steam turbine rotor thermal stress system that can reduce the deep peak load condition in the embodiment of the present application;

[0047] Figure 3 This is a second flow chart of a load increase process control method for a steam turbine rotor thermal stress system capable of reducing deep peak load conditions in an embodiment of the present application;

[0048] Figure 4 This is a flow chart of a method for reducing thermal stress of a steam turbine rotor in deep peak load operation conditions in an embodiment of the present application;

[0049] Figure 5 This is one of the flow charts for controlling the gradual opening of the steam parameter regulating valve in an embodiment of the present application;

[0050] Figure 6 This is the second flow chart of controlling the gradual opening of the steam parameter regulating valve in the embodiment of the present application;

[0051] Figure 7 This is one of the flow charts for controlling the gradual closing of the steam parameter regulating valve in an embodiment of the present application;

[0052] Figure 8 This is the second flow chart of controlling the gradual closing of the steam parameter regulating valve in the embodiment of the present application;

[0053] Fig. 9 This is a structural diagram of a device for reducing thermal stress of a steam turbine rotor in deep peak load operation in an embodiment of the present application;

[0054] Fig.10 It is a schematic diagram of the structure of an electronic device in an embodiment of the present application. DETAILED DESCRIPTION

[0055] To make the purpose, technical solution and advantages of the embodiments of the present invention more clear, the embodiments of the present invention are further described in detail below in conjunction with the accompanying drawings. Here, the exemplary embodiments of the present invention and their descriptions are used to explain the present invention, but are not intended to limit the present invention.

[0056] The information collected in the technical solution of this application is information and data authorized by the user or fully authorized by all parties, and the collection, storage, use, processing, transmission, provision, disclosure and application of relevant data comply with the relevant laws, regulations and standards of relevant countries and regions, take necessary confidentiality measures, do not violate public order and good morals, and provide corresponding operation entrances for users to choose to authorize or refuse.

[0057] In one embodiment, see Figure 1 In order to reduce the thermal stress of the turbine rotor under deep peak-shaving conditions and reduce the safety risks caused by frequent thermal stress on the turbine rotor, the present application provides a system for reducing the thermal stress of the turbine rotor under deep peak-shaving conditions, including: a turbine bypass system and a steam parameter adjustment pipeline arranged in parallel with the turbine bypass system; a steam extraction pipeline leading from the main steam pipeline of the turbine bypass system; a molten salt heat storage system connected to the peak-shaving heat accumulator 1 6 and the peak-shaving heat accumulator 2 19; and a controller 11.

[0058] The steam parameter adjustment pipeline is provided with a steam parameter regulating valve 15 and a peak shaving heat accumulator 16 connected in series; the steam extraction pipeline is provided with a steam parameter regulating valve 2 18 and a peak shaving heat accumulator 2 19 connected in series; the controller 11 is used to collect system measurement point information through signal cables and control the opening of the steam parameter regulating valve 15 and the steam parameter regulating valve 2 18. The system measurement point information includes: main steam temperature T1, reheat steam temperature T2, main steam extraction flow Q1, reheat extraction flow Q2 and turbine fault monitoring system alarm signal W1.

[0059] Specifically, the molten salt heat storage system includes a molten salt heater 12, a cold salt pump 13, a hot salt pump 14, a low-temperature molten salt tank 15 and a high-temperature molten salt tank 16; wherein, the cold salt pump 13 transports the low-temperature molten salt in the low-temperature molten salt tank 15 to the peak-shaving heat accumulator 1 6 and the peak-shaving heat accumulator 2 19 for heat absorption and heating; the high-temperature molten salt enters the high-temperature molten salt tank 16 for storage, and when needed, the high-temperature molten salt is transported to the molten salt heater 12 by the hot salt pump 14 to heat the feed water, and then returns to the low-temperature molten salt tank 15 to form a loop.

[0060] Specifically, the turbine bypass system includes: a main steam valve 4; a high-pressure cylinder 1, an intermediate-pressure cylinder 2 and a low-pressure cylinder 3 arranged in series; wherein one end of the high-pressure cylinder 1 is connected to the main steam valve 4; a reheater 7 having one end connected to the high-pressure cylinder 1 and the other end connected to the intermediate-pressure cylinder 2 and the steam parameter regulating valve 5; a low bypass valve 17 having one end connected to the steam parameter regulating valve 5; a condenser 8 having one end connected to the low-pressure cylinder 3 and the other end connected to the low bypass valve 17 and the peak-shaving heat accumulator 6; a turbine fault monitoring system 9; and a superheater 10 connected to the main steam valve 4 and the steam parameter regulating valve 18.

[0061] The turbine fault monitoring system 9 is connected to the turbine distributed control system (DCS). When the turbine fault monitoring system 9 receives an abnormal (or fault) signal from the turbine distributed control system, the turbine fault monitoring system 9 sends a fault monitoring system alarm signal. The fault monitoring system alarm signal includes but is not limited to the turbine body vibration monitoring system alarm signal and the low-pressure cylinder last stage blade monitoring system alarm signal.

[0062] It is understandable that when the operating condition drops to deep peak-shaving conditions, the boiler combustion state is poor and the reheated steam may find it difficult to reach the rated temperature. When the unit operating state repeatedly switches between deep peak-shaving conditions and normal operating conditions, the medium and low-pressure rotors of the turbine will be subjected to high-frequency alternating stresses due to frequent changes in the reheated steam temperature, thereby greatly reducing the expected service life of the turbine rotor. In severe cases, cracks may appear in the rotor, endangering the safe operation of the unit.

[0063] In order to solve the above technical problems, the present invention proposes a system and operation method for reducing the thermal stress of the turbine rotor under deep peak-shaving conditions, which adds a main steam bypass, a reheat steam bypass and a molten salt heat storage system to the original system. Under deep peak-shaving conditions, part of the main steam and reheat steam are extracted, and the heat therein is stored in the molten salt heat storage system, and then released after the unit load increases, thereby increasing the evaporation amount of the boiler under deep peak-shaving conditions, thereby improving the reheat steam parameters under this condition, reducing the thermal stress on the turbine rotor under deep peak-shaving conditions, and reducing the safety risks caused by frequent thermal stress on the turbine rotor. In addition, when the unit needs to quickly increase the electrical load, the heat in the molten salt heat storage system is released to the water supply system, which can improve the water supply parameters, increase the speed of the unit load increase, and improve the flexibility of the unit.

[0064] Specifically, see Figure 1, a system that can reduce the thermal stress of the turbine rotor in deep peak-shaving conditions combined with a molten salt heat storage system, includes: a high-pressure cylinder 1, an intermediate-pressure cylinder 2, a low-pressure cylinder 3, a main steam valve 4, a steam parameter regulating valve 1 5, a peak-shaving heat accumulator 1 6, a reheater 7, a condenser 8, a turbine fault monitoring system 9, a superheater heater 10, a controller 11, a molten salt heater 12, a cold salt pump 13, a hot salt pump 14, a low-temperature molten salt tank 15, a high-temperature molten salt tank 16, a low bypass valve 17, a steam parameter regulating valve 2 18, and a peak-shaving heat accumulator 2 19. Among them, T1 is the main steam temperature, T2 is the reheat steam temperature, Q1 is the main steam extraction flow, Q2 is the reheat extraction flow, and W1 is the alarm signal of the turbine fault monitoring system.

[0065] The system can reduce the thermal stress of the turbine rotor under deep peak-shaving conditions. On the basis of the conventional turbine bypass system, a steam parameter adjustment pipeline is added, which is arranged in parallel with the original low-pressure bypass pipeline, and a steam parameter regulating valve 15 and a peak-shaving heat accumulator 16 are installed on the pipeline. In addition, in order to balance the axial thrust of the steam turbine, a steam extraction pipeline is also added from the main steam pipeline, and a steam parameter regulating valve 2 18 and a peak-shaving heat accumulator 2 19 are installed on the pipeline; the molten salt heat storage system includes a molten salt heater 12, a cold salt pump 13, a hot salt pump 14, a low-temperature molten salt tank 15, and a high-temperature molten salt tank 16. The cold salt pump 13 transports the low-temperature molten salt in the low-temperature molten salt tank 15 to the peak-shaving heat accumulator 16 and the peak-shaving heat accumulator 2 19 for heat absorption and temperature rise, and the high-temperature molten salt enters the high-temperature molten salt tank 16 for storage. When needed, the high-temperature molten salt is transported to the molten salt heater 12 through the hot salt pump 14 to heat the feed water, and finally returns to the low-temperature molten salt tank 15 to form a complete loop.

[0066] In addition, the controller 11 collects the system's measurement point information through the signal cable, including: main steam temperature T1, reheat steam temperature T2, main steam extraction flow Q1, reheat extraction flow Q2 and turbine fault monitoring system alarm signal W1. The controller 11 also controls the opening of the steam parameter regulating valve 15 and the steam parameter regulating valve 2 18 through the signal cable. The sampling scan cycle of the controller 11 is generally 200ms.

[0067] From the above description, it can be seen that the system, method and device for reducing the thermal stress of the turbine rotor under deep peak-shaving conditions provided in the present application can achieve long-term stability of the reheat steam parameters under various conditions without affecting the electrical load of the unit through automatic control of the steam parameter regulating valve under full-load conditions, thereby reducing the thermal stress on the turbine rotor under deep peak-shaving conditions, greatly reducing the risk of unit non-stopping due to frequent alternating stress on the rotor, improving the reliability of unit operation under deep peak-shaving conditions, and better supporting the consumption of new energy.

[0068] In one embodiment, see Figure 4A method for reducing thermal stress of a steam turbine rotor under deep peak-shaving conditions, applied to the system for reducing thermal stress of a steam turbine rotor under deep peak-shaving conditions, comprising:

[0069] S401: When the unit load enters the deep peak load condition, when it is detected that the temperature difference between the reheat steam temperature and the main steam temperature exceeds the first threshold, the steam parameter regulating valve 1 5 and the steam parameter regulating valve 2 18 are gradually opened to store part of the reheat steam heat in the molten salt heat storage system, maintain the reheat steam temperature, and reduce the thermal stress of the medium and low pressure rotors;

[0070] S402: When it is detected that the unit load returns to the second threshold, the steam parameter regulating valve 1 5 and the steam parameter regulating valve 2 18 are gradually closed, and the heat in the hot salt is released to the water supply system to improve the steam parameters.

[0071] It should be noted that as the load increases, the evaporation of the boiler increases, and it is no longer necessary to extract a portion of the steam to maintain a high evaporation rate. In order to save coal consumption, the regulating valve needs to be closed. Among them, improving steam parameters means releasing the heat in the molten salt into the water supply system through the hot salt pump, heating the water supply system, and assisting in improving steam parameters (mainly including the main steam temperature and the reheat steam temperature).

[0072] It can be understood that the operation control method of the embodiment of the present application for reducing the thermal stress of the turbine rotor under deep peak-shaving conditions is as follows: (1) During the process of unit load reduction, the main steam temperature and the reheat steam temperature are continuously monitored. During this process, the main steam temperature and the reheat steam temperature are maintained at the rated value. At this time, the system provided by the present application does not participate in the regulation; (2) When the unit load enters the deep peak-shaving condition, as the load continues to decrease, the boiler combustion state gradually deteriorates, and the steam parameters, especially the reheat steam parameters, are difficult to maintain at the rated temperature; when the reheat steam temperature continues to decrease and has a large deviation from the main steam temperature, the two steam parameter control valves are gradually opened to store part of the reheat steam heat in the molten salt system In the system, the boiler evaporation volume is guaranteed, thereby maintaining the reheat steam temperature and reducing the thermal stress of the medium and low pressure rotors; (3) During the opening of the two steam parameter regulating valves, if the turbine fault monitoring system 9 issues an alarm, the opening is suspended; (4) As the unit load rises again, the two steam parameter regulating valves are gradually closed, and the high-temperature molten salt is transported to the molten salt heater 12 to assist in improving the steam parameters; (5) When the load increases further or the high-temperature molten salt inventory is small, the system exits the regulation; (6) The opening of the two steam parameter regulating valves is adjusted by the controller 11, which processes the alarm signals collected based on the main steam, reheat steam temperature and the last stage blade monitoring system, and then issues a switch command. Please see the following for details.

[0073] From the above description, it can be seen that the system, method and device for reducing the thermal stress of the turbine rotor under deep peak-shaving conditions provided in the present application can achieve long-term stability of the reheat steam parameters under various conditions without affecting the electrical load of the unit through automatic control of the steam parameter regulating valve under full-load conditions, thereby reducing the thermal stress on the turbine rotor under deep peak-shaving conditions, greatly reducing the risk of unit non-stopping due to frequent alternating stress on the rotor, improving the reliability of unit operation under deep peak-shaving conditions, and better supporting the consumption of new energy.

[0074] In one embodiment, see Figure 5 When it is detected that the temperature difference between the reheat steam temperature and the main steam temperature exceeds the first threshold, the steam parameter regulating valve 1 5 and the steam parameter regulating valve 2 18 are gradually opened, including:

[0075] S501: Determine whether the reheat steam temperature is lower than a set system input temperature, and whether the temperature difference between the reheat steam temperature and the main steam temperature exceeds the first threshold;

[0076] S502: If yes, control the start of the cold salt pump 13 to output the molten salt in the low-temperature molten salt tank 15, and heat it through the peak-shaving heat accumulator 1 6 and the peak-shaving heat accumulator 2 19 and then output it back to the high-temperature molten salt tank 16; and control the opening of the steam parameter regulating valve 1 5 and the steam parameter regulating valve 2 18; meanwhile, continuously collect the main steam extraction flow parameters and the reheat extraction flow parameters, and control the main steam extraction flow parameters to be consistent with the reheat extraction flow parameters to maintain the axial thrust balance of the turbine.

[0077] In one embodiment, see Figure 6 , the method for reducing thermal stress of a steam turbine rotor in a deep peak load condition further comprises:

[0078] S601: During the process of gradually opening the steam parameter regulating valve 1 5 and the steam parameter regulating valve 2 18, continuously monitoring whether the turbine fault monitoring system 9 issues an alarm signal;

[0079] S602: If yes, suspend opening of steam parameter regulating valve 1 5 and steam parameter regulating valve 2 18 until the fault is eliminated, and continue to open steam parameter regulating valve 1 5 and steam parameter regulating valve 2 18 to increase the reheat steam temperature to the preset value and maintain it.

[0080] Understandably, see Figure 2 As shown, the control method for reducing the load reduction process of the steam turbine rotor thermal stress system under deep peak load regulation provided by the present application includes the following steps:

[0081] S201. When the unit load continues to decrease and enters the deep peak-shaving condition (less than 50% of the rated load), the system (i.e., the system for reducing the thermal stress of the turbine rotor in the deep peak-shaving condition provided by the present application) enters the standby state, and the controller continuously monitors the main steam and reheat steam parameters. The monitoring method includes but is not limited to using a temperature sensor to collect and monitor at the measuring point.

[0082] S202. Determine whether the reheat steam parameters are lower than the set system input temperature t, or whether the temperature difference between the reheat steam temperature and the main steam temperature is greater than Δt; if the reheat steam temperature is not lower than t or the temperature difference with the main steam is less than (or not greater than) Δt, then continue monitoring and the system does not take any action; if the reheat steam temperature is lower than t or the temperature difference with the main steam is greater than Δt, proceed to the next step and the system officially enters the adjustment state.

[0083] For example, if the rated reheat steam temperature of a plant is 560°C, t can be set to 540°C and Δt to 20°C.

[0084] S203, the system enters the regulation state, starts the cold salt pump 13, transports the molten salt in the low-temperature molten salt tank 15, and returns it to the high-temperature molten salt tank 16 after being heated by the peak-shaving heat accumulator 16 and the peak-shaving heat accumulator 2 19, and gradually opens the steam parameter regulating valve 15 and the steam parameter regulating valve 2 18. In this process, the controller continuously collects the main steam extraction flow rate and the reheat extraction flow rate, and controls the two parameters to be consistent to maintain the axial thrust balance of the steam turbine. Among them, the monitoring method of steam flow includes but is not limited to using a steam flow sensor to collect and monitor at the measuring point.

[0085] S204. During the continuous opening of the steam parameter regulating valve 15 and the steam parameter regulating valve 2 18, the controller continuously monitors the alarm signal of the steam turbine fault monitoring system and judges the operation status of the steam turbine at any time, such as unit vibration, axial displacement, etc.; if the alarm signal of the steam turbine fault monitoring system is issued, the next step is entered. Among them, the steam turbine fault monitoring system will issue an alarm signal after receiving the abnormal (or fault) signal of the steam turbine distributed control system. Furthermore, since the controller is electrically connected to the steam turbine fault monitoring system, when the steam turbine fault monitoring system issues an alarm signal, the controller can receive the alarm signal and perform subsequent control.

[0086] S205, suspend opening of steam parameter regulating valve 1 5 and steam parameter regulating valve 2 18, and return to close 1%, maintaining the status quo, until the operator manually clicks to continue and then continues to open the steam parameter regulating valve.

[0087] S206, keep opening the two steam parameter regulating valves until the reheat steam temperature rises to the preset t1, and continue to adjust the steam parameter regulating valve 1 5 and the steam parameter regulating valve 2 18 to maintain the reheat steam temperature within t1±5°C. For example, if the rated reheat steam temperature of a plant is 560°C, t1 can be set to 550°C.

[0088] It should be noted that the molten salt reserves in the low-temperature molten salt tank are limited. According to the current operating load of a power plant, its reserves should be able to meet the heat storage requirements for continuous deep peak regulation for 7 hours.

[0089] From the above description, it can be seen that the method for reducing the thermal stress of the turbine rotor under deep peak-shaving conditions provided in the present application can, when the unit load enters the deep peak-shaving condition, when it is detected that the temperature difference between the reheat steam temperature and the main steam temperature exceeds the first threshold, control the gradual opening of the steam parameter regulating valve 1 5 and the steam parameter regulating valve 2 18 to store part of the reheat steam heat in the molten salt heat storage system, maintain the reheat steam temperature, and reduce the thermal stress of the medium and low pressure rotors.

[0090] In one embodiment, see Figure 7 When it is detected that the unit load rises back to the second threshold, the steam parameter regulating valve 1 5 and the steam parameter regulating valve 2 18 are gradually closed by control, including:

[0091] S701: When it is detected that the load of the unit has returned to the second threshold, the steam parameter regulating valve 1 5 and the steam parameter regulating valve 2 18 are gradually fully closed;

[0092] S702: Start the hot salt pump 14 to output the high-temperature molten salt in the high-temperature molten salt tank 16, and heat the feed water through the molten salt heater 12 to increase the unit load. After the steam parameter regulating valve 1 5 and the steam parameter regulating valve 2 18 are all closed, stop the cold salt pump 13.

[0093] In one embodiment, see Figure 8 , the method for reducing thermal stress of a steam turbine rotor in a deep peak load condition further comprises:

[0094] S801: When it is detected that the load of the unit continues to rise to more than 50%, it is determined that the unit is out of the deep peak load regulation condition;

[0095] S802: Control the hot salt pump 14 to continue operating until the liquid level in the high-temperature molten salt tank 16 drops to a preset low liquid level.

[0096] Understandably, see Figure 3 As shown, a control method for reducing the load increase process of a steam turbine rotor thermal stress system under deep peak load regulation conditions includes the following steps:

[0097] S301. The unit load gradually increases, and the reheat steam temperature gradually increases, but the system is still in the adjustment state. By adjusting the two steam parameter regulating valves, the reheat steam temperature is controlled to be maintained within t1±5℃.

[0098] S302, the load continues to rise, the steam temperature continues to rise, and the two steam parameter regulating valves are gradually closed; if the load rises quickly, it may exceed the range of the two steam parameter regulating valves, that is, the reheat steam temperature rises to the preset t2, and then proceed to the next step.

[0099] For example, if the rated reheat steam temperature of a plant is 560℃, t2 can be set to 557℃.

[0100] S303, gradually close the two steam parameter regulating valves, start the hot salt pump 14, transport the high-temperature molten salt in the high-temperature molten salt tank 16, heat the feed water through the molten salt heater 12, and assist in quickly increasing the unit load. After the two steam parameter regulating valves are fully closed, stop the cold salt pump 13.

[0101] S304, the unit load continues to rise to more than 50%, leaving the deep peak regulation condition. At this time, the system exits the regulation state, leaving only the hot salt pump 14 to continue running, using high-temperature molten salt to heat the feed water, releasing the heat absorbed under the deep regulation condition, and reducing the amount of boiler coal until the liquid level in the high-temperature molten salt tank drops to a low level.

[0102] The above is the adjustment process of this system in the full load section.

[0103] From the above description, it can be seen that the method provided in the present application for reducing the thermal stress of the turbine rotor under deep peak-shaving conditions can control the gradual closing of the steam parameter regulating valve 1 5 and the steam parameter regulating valve 2 18 to increase the steam parameters when it is detected that the unit load has returned to the second threshold.

[0104] Based on the same inventive concept, the embodiments of the present application also provide a device for reducing the thermal stress of a steam turbine rotor under deep peak-shaving conditions, which can be used to implement the methods described in the above embodiments, as described in the following embodiments. Since the principle of solving the problem by the device for reducing the thermal stress of a steam turbine rotor under deep peak-shaving conditions is similar to the method for reducing the thermal stress of a steam turbine rotor under deep peak-shaving conditions, the implementation of the device for reducing the thermal stress of a steam turbine rotor under deep peak-shaving conditions can refer to the implementation of the method for determining the software performance benchmark, and the repetitions will not be repeated. As used below, the terms "unit" or "module" may be a combination of software and / or hardware that implements a predetermined function. Although the system described in the following embodiments is preferably implemented in software, the implementation of hardware, or a combination of software and hardware, is also possible and conceived.

[0105] In one embodiment, see Fig. 9In order to reduce the thermal stress of a steam turbine rotor under deep peak-shaving conditions and reduce the safety risk caused by frequent thermal stress on the steam turbine rotor, the present application provides a device for reducing the thermal stress of a steam turbine rotor under deep peak-shaving conditions, which is applied to the system for reducing the thermal stress of a steam turbine rotor under deep peak-shaving conditions, and includes:

[0106] The regulating valve opening unit 901 is used to control the gradual opening of the steam parameter regulating valve 1 5 and the steam parameter regulating valve 2 18 when it is detected that the temperature difference between the reheat steam temperature and the main steam temperature exceeds the first threshold value after the unit load enters the deep peak regulation condition, so as to store part of the reheat steam heat in the molten salt heat storage system, maintain the reheat steam temperature, and reduce the thermal stress of the medium and low pressure rotors;

[0107] The regulating valve closing unit 902 is used to control the gradual closing of the steam parameter regulating valve 1 5 and the steam parameter regulating valve 2 18 to increase the steam parameters when it is detected that the unit load returns to the second threshold.

[0108] From the hardware level, in order to reduce the thermal stress on the steam turbine rotor under deep peak load conditions and reduce the safety risks caused by frequent thermal stress on the steam turbine rotor, the present application provides an embodiment of an electronic device for implementing all or part of the content of the method for reducing the thermal stress of the steam turbine rotor under deep peak load conditions, and the electronic device specifically includes the following content:

[0109] Processor, memory, communication interface and bus; wherein the processor, memory and communication interface communicate with each other through the bus; the communication interface is used to realize information transmission between the device for reducing thermal stress of a steam turbine rotor under deep peak-shaving conditions and related equipment such as core business systems, user terminals and related databases; the logic controller can be a desktop computer, a tablet computer and a mobile terminal, etc., but the present embodiment is not limited thereto. In the present embodiment, the logic controller can be implemented with reference to the embodiment of the method for reducing thermal stress of a steam turbine rotor under deep peak-shaving conditions and the embodiment of the device for reducing thermal stress of a steam turbine rotor under deep peak-shaving conditions in the embodiment, and the contents thereof are incorporated herein and the repeated parts are not repeated.

[0110] It is understandable that the user terminal may include a smart phone, a tablet electronic device, a network set-top box, a portable computer, a desktop computer, a personal digital assistant (PDA), a vehicle-mounted device, a smart wearable device, etc. Among them, the smart wearable device may include smart glasses, a smart watch, a smart bracelet, etc.

[0111] In practical applications, part of the method for reducing the thermal stress of the turbine rotor in deep peak load conditions can be performed on the electronic device side as described above, or all operations can be completed in the client device. The specific selection can be based on the processing capability of the client device and the limitations of the user's usage scenario. This application does not limit this. If all operations are completed in the client device, the client device may also include a processor.

[0112] The client device may have a communication module (i.e., a communication unit) that can communicate with a remote server to achieve data transmission with the server. The server may include a server on the task scheduling center side, and other implementation scenarios may also include a server on an intermediate platform, such as a server on a third-party server platform that has a communication link with the task scheduling center server. The server may include a single computer device, or a server cluster consisting of multiple servers, or a server structure of a distributed device.

[0113] Fig.10 FIG. 9 is a schematic block diagram of the system structure of the electronic device 9600 according to an embodiment of the present application. Fig.10 As shown, the electronic device 9600 may include a central processor 9100 and a memory 9140; the memory 9140 is coupled to the central processor 9100. It is worth noting that Fig.10 is exemplary; other types of structures may also be used to supplement or replace this structure to implement telecommunication functions or other functions.

[0114] In one embodiment, the method function of reducing the thermal stress of the turbine rotor in deep peak load condition can be integrated into the central processor 9100. The central processor 9100 can be configured to perform the following control:

[0115] S401: When the unit load enters the deep peak load condition, when it is detected that the temperature difference between the reheat steam temperature and the main steam temperature exceeds the first threshold, the steam parameter regulating valve 1 5 and the steam parameter regulating valve 2 18 are gradually opened to store part of the reheat steam heat in the molten salt heat storage system, maintain the reheat steam temperature, and reduce the thermal stress of the medium and low pressure rotors;

[0116] S402: When it is detected that the unit load returns to the second threshold, the steam parameter regulating valve 1 5 and the steam parameter regulating valve 2 18 are gradually closed to increase the steam parameters.

[0117] From the above description, it can be seen that the system, method and device for reducing the thermal stress of the turbine rotor under deep peak-shaving conditions provided in the present application can achieve long-term stability of the reheat steam parameters under various conditions without affecting the electrical load of the unit through automatic control of the steam parameter regulating valve under full-load conditions, thereby reducing the thermal stress on the turbine rotor under deep peak-shaving conditions, greatly reducing the risk of unit non-stopping due to frequent alternating stress on the rotor, improving the reliability of unit operation under deep peak-shaving conditions, and better supporting the consumption of new energy.

[0118] In another embodiment, the device for reducing the thermal stress of the turbine rotor under deep peak-shaving conditions can be configured separately from the central processing unit 9100. For example, the data composite transmission device for reducing the thermal stress of the turbine rotor under deep peak-shaving conditions can be configured as a chip connected to the central processing unit 9100, and the function of the method for reducing the thermal stress of the turbine rotor under deep peak-shaving conditions is implemented through the control of the central processing unit.

[0119] like Fig.10 As shown, the electronic device 9600 may also include: a communication module 9110, an input unit 9120, an audio processor 9130, a display 9160, and a power supply 9170. It is worth noting that the electronic device 9600 does not necessarily have to include Fig.10 In addition, the electronic device 9600 may also include Fig.10 For components not shown, reference may be made to the prior art.

[0120] like Fig.10 As shown, the central processing unit 9100 is sometimes also referred to as a controller or an operation control, and may include a microprocessor or other processor device and / or logic device. The central processing unit 9100 receives input and controls the operation of various components of the electronic device 9600.

[0121] The memory 9140 may be, for example, one or more of a cache, a flash memory, a hard drive, a removable medium, a volatile memory, a non-volatile memory or other suitable devices. The above-mentioned information related to the failure may be stored, and a program for executing the relevant information may also be stored. The CPU 9100 may execute the program stored in the memory 9140 to implement information storage or processing, etc.

[0122] The input unit 9120 provides input to the central processing unit 9100. The input unit 9120 is, for example, a key or a touch input device. The power supply 9170 is used to provide power to the electronic device 9600. The display 9160 is used to display display objects such as images and texts. The display may be, for example, an LCD display, but is not limited thereto.

[0123] The memory 9140 may be a solid-state memory, such as a read-only memory (ROM), a random access memory (RAM), a SIM card, etc. It may also be a memory that saves information even when the power is off, can be selectively erased, and is provided with more data, examples of which are sometimes referred to as EPROMs, etc. The memory 9140 may also be some other type of device. The memory 9140 includes a buffer memory 9141 (sometimes referred to as a buffer). The memory 9140 may include an application / function storage unit 9142, which is used to store application programs and function programs or processes for executing the operation of the electronic device 9600 through the central processor 9100.

[0124] The memory 9140 may also include a data storage unit 9143 for storing data, such as contacts, digital data, pictures, sounds, and / or any other data used by the electronic device. The driver storage unit 9144 of the memory 9140 may include various drivers for communication functions of the electronic device and / or for executing other functions of the electronic device (such as messaging applications, address book applications, etc.).

[0125] The communication module 9110 is a transmitter / receiver 9110 that sends and receives signals via an antenna 9111. The communication module (transmitter / receiver) 9110 is coupled to the central processor 9100 to provide input signals and receive output signals, which may be the same as the case of a conventional mobile communication terminal.

[0126] Based on different communication technologies, multiple communication modules 9110 may be provided in the same electronic device, such as a cellular network module, a Bluetooth module and / or a wireless LAN module. The communication module (transmitter / receiver) 9110 is also coupled to a speaker 9131 and a microphone 9132 via an audio processor 9130 to provide an audio output via the speaker 9131 and receive an audio input from the microphone 9132, thereby realizing a common telecommunication function. The audio processor 9130 may include any suitable buffer, decoder, amplifier, etc. In addition, the audio processor 9130 is also coupled to the central processor 9100, so that recording can be performed on the local machine through the microphone 9132, and the sound stored on the local machine can be played through the speaker 9131.

[0127] The embodiments of the present application also provide a computer-readable storage medium capable of implementing all the steps of the method for reducing the thermal stress of a steam turbine rotor under deep peak-shaving conditions in the above-mentioned embodiments, where the execution subject is a server or a client. The computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, all the steps of the method for reducing the thermal stress of a steam turbine rotor under deep peak-shaving conditions in the above-mentioned embodiments are implemented. For example, when the processor executes the computer program, the following steps are implemented:

[0128] S401: When the unit load enters the deep peak load condition, when it is detected that the temperature difference between the reheat steam temperature and the main steam temperature exceeds the first threshold, the steam parameter regulating valve 1 5 and the steam parameter regulating valve 2 18 are gradually opened to store part of the reheat steam heat in the molten salt heat storage system, maintain the reheat steam temperature, and reduce the thermal stress of the medium and low pressure rotors;

[0129] S402: When it is detected that the unit load returns to the second threshold, the steam parameter regulating valve 1 5 and the steam parameter regulating valve 2 18 are gradually closed to increase the steam parameters.

[0130] From the above description, it can be seen that the system, method and device for reducing the thermal stress of the turbine rotor under deep peak-shaving conditions provided in the present application can achieve long-term stability of the reheat steam parameters under various conditions without affecting the electrical load of the unit through automatic control of the steam parameter regulating valve under full-load conditions, thereby reducing the thermal stress on the turbine rotor under deep peak-shaving conditions, greatly reducing the risk of unit non-stopping due to frequent alternating stress on the rotor, improving the reliability of unit operation under deep peak-shaving conditions, and better supporting the consumption of new energy.

[0131] It will be appreciated by those skilled in the art that embodiments of the present invention may be provided as methods, devices, or computer program products. Therefore, the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0132] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (apparatus), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0133] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0134] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0135] The present invention uses specific embodiments to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea. At the same time, for those skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as a limitation on the present invention.

Claims

1. A system for reducing thermal stress of a steam turbine rotor in deep peak load operation, characterized in that: include: A steam turbine bypass system and a steam parameter adjustment pipeline arranged in parallel with the steam turbine bypass system; wherein the steam parameter adjustment pipeline is provided with a steam parameter regulating valve (5) and a peak load accumulator (6) connected in series in sequence; A steam extraction pipeline led out from the main steam pipeline of the turbine bypass system; wherein, on the steam extraction pipeline, a second steam parameter regulating valve (18) and a second peak-shaving heat accumulator (19) are arranged in series; A molten salt heat storage system connected to the peak-shaving heat accumulator 1 (6) and the peak-shaving heat accumulator 2 (19); The controller (11) is used to collect system measurement point information through a signal cable and control the opening of the steam parameter regulating valve 1 (5) and the steam parameter regulating valve 2 (18).

2. The system for reducing thermal stress of a steam turbine rotor in deep peak load operation according to claim 1, characterized in that: The molten salt heat storage system comprises a molten salt heater (12), a cold salt pump (13), a hot salt pump (14), a low-temperature molten salt tank (15) and a high-temperature molten salt tank (16); wherein the cold salt pump (13) transports the low-temperature molten salt in the low-temperature molten salt tank (15) to the peak-shaving heat accumulator 1 (6) and the peak-shaving heat accumulator 2 (19) for heat absorption and temperature rise; the high-temperature molten salt enters the high-temperature molten salt tank (16) for storage, and when needed, the high-temperature molten salt is transported to the molten salt heater (12) by the hot salt pump (14) to heat the feed water, and then returns to the low-temperature molten salt tank (15) to form a loop.

3. The system for reducing thermal stress of a steam turbine rotor in deep peak load operation according to claim 1, characterized in that: The steam turbine bypass system comprises: Main steam valve (4); A high-pressure cylinder (1), a medium-pressure cylinder (2) and a low-pressure cylinder (3) are arranged in series; wherein one end of the high-pressure cylinder (1) is connected to the main steam valve (4); A reheater (7) connected to the high-pressure cylinder (1) at one end and to the medium-pressure cylinder (2) and the steam parameter regulating valve 1 (5) at the other end; A low bypass valve (17) having one end connected to the steam parameter regulating valve 1 (5); A condenser (8) having one end connected to the low-pressure cylinder (3) and the other end connected to the low-pressure bypass valve (17) and the peak-shaving heat accumulator (6); Steam turbine fault monitoring system (9); A superheater (10) connected to the main steam valve (4) and the second steam parameter regulating valve (18).

4. The system for reducing thermal stress of a steam turbine rotor in deep peak load operation according to claim 1, characterized in that: The system measurement point information includes: main steam temperature (T1), reheat steam temperature (T2), main steam extraction flow (Q1), reheat extraction flow (Q2) and turbine fault monitoring system alarm signal (W1).

5. A method for reducing thermal stress of a steam turbine rotor under deep peak load operation, applied to the system for reducing thermal stress of a steam turbine rotor under deep peak load operation as claimed in any one of claims 1 to 4, characterized in that: include: When the unit load enters the deep peak load regulation condition, when it is detected that the temperature difference between the reheat steam temperature and the main steam temperature exceeds the first threshold value, the steam parameter regulating valve 1 (5) and the steam parameter regulating valve 2 (18) are gradually opened to store part of the reheat steam heat in the molten salt heat storage system, maintain the reheat steam temperature, and reduce the thermal stress of the medium and low pressure rotors; When it is detected that the unit load returns to the second threshold, the steam parameter regulating valve 1 (5) and the steam parameter regulating valve 2 (18) are controlled to be gradually closed to increase the steam parameters.

6. The method for reducing thermal stress of a steam turbine rotor in deep peak load operation according to claim 5, characterized in that: When it is detected that the temperature difference between the reheat steam temperature and the main steam temperature exceeds the first threshold, the steam parameter regulating valve 1 (5) and the steam parameter regulating valve 2 (18) are gradually opened, comprising: Determining whether the reheat steam temperature is lower than a set system input temperature, and whether the temperature difference between the reheat steam temperature and the main steam temperature exceeds the first threshold; If so, the cold salt pump (13) is controlled to start, the molten salt in the low-temperature molten salt tank (15) is output, and after being heated by the peak-shaving heat accumulator 1 (6) and the peak-shaving heat accumulator 2 (19), it is output back to the high-temperature molten salt tank (16); and the steam parameter regulating valve 1 (5) and the steam parameter regulating valve 2 (18) are controlled to open; during this period, the main steam extraction flow parameter and the reheat extraction flow parameter are continuously collected, and the main steam extraction flow parameter is controlled to be consistent with the reheat extraction flow parameter to maintain the axial thrust balance of the turbine.

7. The method for reducing thermal stress of a steam turbine rotor in deep peak load operation according to claim 6, characterized in that: Also includes: In the process of gradually opening the steam parameter regulating valve 1 (5) and the steam parameter regulating valve 2 (18), continuously monitoring whether the turbine fault monitoring system (9) issues an alarm signal; If so, the steam parameter regulating valve 1 (5) and the steam parameter regulating valve 2 (18) are temporarily closed until the fault is rectified, and then the steam parameter regulating valve 1 (5) and the steam parameter regulating valve 2 (18) are continuously opened to increase the reheat steam temperature to the preset value and maintain it.

8. The method for reducing thermal stress of a steam turbine rotor in deep peak load operation according to claim 5, characterized in that: When it is detected that the unit load has risen to the second threshold, the steam parameter regulating valve 1 (5) and the steam parameter regulating valve 2 (18) are gradually closed by control, comprising: When it is detected that the load of the unit has returned to a second threshold, the steam parameter regulating valve 1 (5) and the steam parameter regulating valve 2 (18) are gradually fully closed by control; The hot salt pump (14) is started to output the high-temperature molten salt in the high-temperature molten salt tank (16) and heat the feed water through the molten salt heater (12) to increase the load of the unit. After the steam parameter regulating valve 1 (5) and the steam parameter regulating valve 2 (18) are all closed, the cold salt pump (13) is stopped.

9. The method for reducing thermal stress of a steam turbine rotor in deep peak load operation according to claim 8, characterized in that: Also includes: When it is detected that the load of the unit continues to rise to more than 50%, it is determined that the deep peak load regulation condition is out of operation; The hot salt pump (14) is controlled to continue to operate until the liquid level in the high-temperature molten salt tank (16) drops to a preset low liquid level.

10. A device for reducing thermal stress of a steam turbine rotor under deep peak load operation, applied to the system for reducing thermal stress of a steam turbine rotor under deep peak load operation as claimed in any one of claims 1 to 4, characterized in that: include: The regulating valve opening unit is used for gradually opening the steam parameter regulating valve 1 (5) and the steam parameter regulating valve 2 (18) when it is detected that the temperature difference between the reheat steam temperature and the main steam temperature exceeds a first threshold value after the unit load enters a deep peak regulation condition, so as to store part of the reheat steam heat in the molten salt heat storage system, maintain the reheat steam temperature, and reduce the thermal stress of the medium and low pressure rotors; The regulating valve closing unit is used to control the gradual closing of the steam parameter regulating valve 1 (5) and the steam parameter regulating valve 2 (18) to increase the steam parameters when it is detected that the unit load returns to a second threshold.

11. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the program, the steps of the method for reducing the thermal stress of a turbine rotor under deep peak load operation conditions as described in any one of claims 5 to 9 are implemented.

12. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method for reducing thermal stress of a turbine rotor under deep peak load operation conditions as described in any one of claims 5 to 9 are implemented.

13. A computer program product comprising a computer program / instructions, characterized in that When the computer program / instructions are executed by a processor, the steps of the method for reducing thermal stress of a turbine rotor under deep peak load operation conditions as described in any one of claims 5 to 9 are implemented.

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