A new extraction steam turbine differential pressure system and working method

Abstract

The present application provides a new extraction steam turbine differential pressure system and working method, which relate to the field of steam turbines. The new extraction steam turbine working method comprises: obtaining the extraction pressure of the extraction steam pipeline and the wheel chamber pressure of the wheel chamber under the current operating conditions of the extraction steam turbine; judging whether the extraction pressure and the wheel chamber pressure meet the preset safety range, and controlling the operation or shutdown of the extraction steam turbine according to the judgment result. The new extraction steam turbine differential pressure system and working method according to the present application solves the problem that the existing steam turbine pressure protection scheme cannot accurately judge the safety state of the extraction steam turbine and will narrow the safety range of the extraction steam turbine operation, and can more accurately control the working state of the extraction steam turbine within a reasonable safety range.

Description

Technical Field

[0001] The present application relates to the field of steam turbines, and in particular to a new extraction steam turbine differential pressure system and working method. Background Art

[0002] Extraction steam turbines are key power devices in industries such as petrochemicals and power generation. They mainly use steam expansion as a power source and operate within a fluctuating steam parameter range. However, when the steam pressure fluctuation exceeds the design range of the pipeline network, the extraction steam turbine will be damaged. In order to protect the extraction steam turbine from damage, pressure protection measures are usually implemented for the extraction steam turbine.

[0003] At present, the pressure protection for extraction steam turbines is mainly single-point pressure protection. Specifically, during the operation of the extraction steam turbine, the extraction pressure is monitored in real time. When the pressure at the monitoring point exceeds the predetermined range, the alarm and shutdown process are initiated. However, in such a pressure protection scheme, since only the value of a single pressure point is used as the basis for judging the safety of the unit, it is impossible to accurately judge the safety status of the extraction steam turbine and control the extraction steam turbine. Summary of the invention

[0004] In view of this, the purpose of the present application is to provide a new extraction steam turbine differential pressure system and working method, which obtains both the extraction pressure and the turbine chamber pressure and controls the working state of the steam turbine based on these two pressures, thereby solving the problem that the existing steam turbine pressure protection scheme cannot accurately determine the safety state of the extraction steam turbine, and can more accurately control the working state of the extraction steam turbine within a reasonable safety range.

[0005] According to one aspect of the present application, a new extraction steam turbine operating method is provided, the extraction steam turbine comprising an extraction pipe and a wheel chamber, the new extraction steam turbine operating method comprising: obtaining the extraction pressure of the extraction pipe and the wheel chamber pressure of the wheel chamber under the current operating conditions of the extraction steam turbine; judging whether the extraction pressure and the wheel chamber pressure satisfy a preset safety range, and controlling the operation or shutdown of the extraction steam turbine according to the judgment result.

[0006] Optionally, the extraction steam turbine includes a steam inlet, an intermediate steam point and an exhaust port arranged along the flow direction of the steam flow, the steam flow path from the steam inlet to the intermediate steam point forms a first expansion section of the extraction steam turbine, and the steam flow path from the intermediate steam point to the exhaust port forms a second expansion section of the extraction steam turbine, and the preset safety range is determined according to the extraction pressure safety range and the wheel chamber pressure safety range, the extraction pressure safety range is determined based on the allowable range of steam pressure difference of the second expansion section and the exhaust pressure range of the exhaust port, and the wheel chamber pressure safety range is determined based on the extraction pressure safety range and the allowable range of steam pressure difference of the first expansion section.

[0007] Optionally, the extraction steam turbine also includes a second blade arranged on the steam flow path between the intermediate steam point and the exhaust port; the extraction pressure safety range is determined in the following manner: according to the allowable stress of the second blade, the maximum allowable value of the steam pressure difference of the second expansion section is determined, wherein the allowable stress of the second blade is positively correlated with the steam pressure difference of the second expansion section; according to the maximum allowable value of the steam pressure difference of the second expansion section and the minimum exhaust pressure of the exhaust pressure range of the exhaust port, the upper limit value of the extraction pressure safety range is determined; according to the allowable temperature of the second blade, the minimum allowable value of the steam pressure difference of the second expansion section is determined, wherein the allowable temperature of the second blade is negatively correlated with the steam pressure difference of the second expansion section; according to the minimum allowable value of the steam pressure difference of the second expansion section and the maximum exhaust pressure of the exhaust pressure range of the exhaust port, the lower limit value of the extraction pressure safety range is determined; according to the upper limit value and the lower limit value of the extraction pressure safety range, the extraction pressure safety range is determined.

[0008] Optionally, the extraction steam turbine also includes a first blade arranged on the steam flow path between the steam inlet and the intermediate steam point; the wheel chamber pressure safety range is determined in the following manner: according to the allowable stress and allowable thrust of the first blade, the maximum allowable value of the steam pressure difference of the first expansion section is determined, wherein the allowable stress and allowable thrust of the first blade are positively correlated with the steam pressure difference of the first expansion section; according to the maximum allowable value of the steam pressure difference of the first expansion section and the extraction pressure safety range, the upper limit curve of the wheel chamber pressure safety range is determined; according to the allowable temperature of the first blade and the extraction pressure safety range, the minimum allowable value of the steam pressure difference of the first expansion section is determined, wherein the allowable temperature of the first blade is negatively correlated with the steam pressure difference of the first expansion section; according to the minimum allowable value of the steam pressure difference of the first expansion section and the extraction pressure safety range, the lower limit curve of the wheel chamber pressure safety range is determined; according to the upper limit curve and the lower limit curve of the wheel chamber pressure safety range, the wheel chamber pressure safety range is determined.

[0009] Optionally, it is determined whether the extraction pressure and the wheel chamber pressure satisfy a preset safety range, and the extraction steam turbine is controlled to operate or shut down according to the determination result, including: when the determination result indicates that the extraction pressure and the wheel chamber pressure do not satisfy the preset safety range, the extraction steam turbine is controlled to shut down or be in an alarm operation state; when the determination result indicates that the extraction pressure and the wheel chamber pressure satisfy the preset safety range, it is determined whether the extraction pressure and the wheel chamber pressure satisfy a preset safety sub-range and the operation of the extraction steam turbine is controlled according to the determination result of whether the extraction pressure and the wheel chamber pressure satisfy the preset safety sub-range, wherein the preset safety sub-range is smaller than the range of the preset safety range.

[0010] Optionally, judging whether the extraction pressure and the wheel chamber pressure satisfy a preset safety sub-range and controlling the operation of the extraction steam turbine according to the judgment result of whether the extraction pressure and the wheel chamber pressure satisfy the preset safety sub-range include: when the judgment result of whether the extraction pressure and the wheel chamber pressure satisfy the preset safety sub-range indicates that the extraction pressure and the wheel chamber pressure do not satisfy the preset safety sub-range, controlling the extraction steam turbine to be in an alarm operation state and issuing an alarm; and when the judgment result of whether the extraction pressure and the wheel chamber pressure satisfy the preset safety sub-range indicates that the extraction pressure and the wheel chamber pressure satisfy the preset safety sub-range, controlling the extraction steam turbine to keep operating.

[0011] Optionally, controlling the extraction steam turbine to be in an alarm operating state and issuing an alarm comprises: obtaining an alarm time point of the extraction steam turbine alarm; monitoring whether the operating state of the extraction steam turbine is in the alarm operating state at a monitoring time point that is a predetermined time apart from the alarm time point, and controlling the operation or shutdown of the extraction steam turbine according to the monitoring result, wherein, when it is monitored at the monitoring time point that the operating state of the extraction steam turbine is in the alarm operating state, the extraction steam turbine is controlled to be shut down; and when it is monitored at the monitoring time point that the extraction steam turbine is not in the alarm operating state, the extraction steam turbine is controlled to keep operating.

[0012] According to another aspect of the present application, a new extraction steam turbine differential pressure system is provided, the extraction steam turbine includes an extraction pipe and a wheel chamber, the new extraction steam turbine differential pressure system includes: a first pressure sensor, the first pressure sensor is arranged in the wheel chamber of the extraction steam turbine, so as to detect the wheel chamber pressure of the wheel chamber; a second pressure sensor, the second pressure sensor is arranged in the extraction pipe of the extraction steam turbine, so as to detect the extraction pressure of the extraction pipe; a memory, the memory stores a preset safety range; a processor, the processor is communicatively connected to the first pressure sensor and the second pressure sensor to receive the wheel chamber pressure signal from the first pressure sensor and the extraction pressure signal from the second pressure sensor, the processor is communicatively connected to the memory to obtain the preset safety range stored in the memory; a controller, the controller is communicatively connected to the processor and to the extraction steam turbine to send a control signal to the extraction steam turbine to control the operation or shutdown of the extraction steam turbine.

[0013] Optionally, the new extraction steam turbine differential pressure system also includes a first pressure transmission device and a second pressure transmission device, the first pressure sensor is communicatively connected to the first pressure transmission device, the second pressure sensor is communicatively connected to the second pressure transmission device, and the first pressure transmission device and the second pressure transmission device transmit the wheel chamber pressure signal and the extraction pressure signal to the processor respectively.

[0014] Optionally, the new extraction steam turbine differential pressure system further comprises a pressure display instrument, which is communicatively connected to the first pressure sensor to receive the wheel chamber pressure signal from the first pressure sensor and visually display the wheel chamber pressure signal. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0016] Figure 1 is a schematic structural diagram showing an extraction steam turbine according to an embodiment of the present application;

[0017] Figure 2 is a schematic diagram showing that a first pressure sensor of a differential pressure system of an extraction steam turbine according to an embodiment of the present application is installed in a turbine chamber;

[0018] Figure 3 is a schematic diagram showing the connection between a pressure sensor, a pressure transmission device and a pressure display instrument of a differential pressure system of an extraction steam turbine according to an embodiment of the present application;

[0019] Figure 4 is a schematic block diagram showing a differential pressure system of an extraction steam turbine according to an embodiment of the present application;

[0020] Figure 5 is a schematic flow chart showing a working method of an extraction steam turbine according to an embodiment of the present application;

[0021] Figure 6 is a schematic diagram showing a safety range and a safety sub-range in a working method of an extraction steam turbine according to an embodiment of the present application;

[0022] Figure 7 1 is a logic diagram of controlling the working state of the extraction steam turbine, showing the working method of the extraction steam turbine according to the embodiment of the present application.

[0023] Icons: 10-wheel chamber; 11-lower wheel chamber; 20-steam inlet; 30-regulating stage blades; 40-drum stage blades; 50-chamber; 51-first chamber; 52-second chamber; 53-overflow pipe; 60-exhaust port; 70-steam extraction port; 80-steam extraction pipe; 81-steam extraction point; 90-steam exhaust pipe; 100-first pressure sensor; 110-first pressure transmission device; 120-pressure display instrument; 200-second pressure sensor; 210-second pressure transmission device; 300-first pressure sensor mounting structure; 310-opening; 320-pipe connection; 400-processor; 500-memory. DETAILED DESCRIPTION

[0024] To make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all of the embodiments. The components of the embodiments of the present application usually described and shown in the drawings here can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the application claimed for protection, but merely represents the selected embodiments of the present application. Based on the embodiments of the present application, each other embodiment obtained by those skilled in the art without making creative work belongs to the scope of protection of the present application.

[0025] One aspect of the present application provides a new extraction steam turbine differential pressure system.

[0026] Figure 1 The main structural diagram of the flow-through part of the extraction steam turbine is shown in FIG. Figure 1 As shown, the extraction steam turbine may include a turbine chamber 10 , a steam inlet 20 , a regulating stage blade 30 , a drum stage blade 40 , a chamber 50 , a steam exhaust port 60 , and a steam extraction port 70 .

[0027] Specifically, steam can enter the steam turbine from the steam inlet 20, pass through the regulating blades 30 and enter the turbine chamber 10. The turbine chamber 10 may have a turbine chamber pressure P R After steam comes out of the turbine chamber 10, it can pass through the drum stage blades 40 and enter the chamber 50. Here, the chamber 50 may include a first chamber 51 and a second chamber 52. The first chamber 51 may be connected to the second chamber 52 through an overflow pipe 53. The first chamber 51 may be directly connected to the steam extraction port 70. The steam extraction port 70 may be externally connected to a steam extraction pipe 80.

[0028] The steam pressure at the first chamber 51 may be approximately equal to the steam pressure P in the steam extraction pipe 80. E Here, part of the steam in the steam flow is extracted through the steam extraction port 70 and enters the steam extraction pipe 80, and the remaining steam can enter the second chamber 52 through the overflow pipe 53, and continue to work through the drum stage blades 40, and finally reach the exhaust port 60. The exhaust port 60 can be directly connected to the exhaust pipe 90. The steam pressure at the second chamber 52 can be approximately equal to the steam pressure P in the exhaust pipe 90. A .

[0029] According to an embodiment of the present application, an extraction steam turbine differential pressure system may include a first pressure sensor 100 and a second pressure sensor 200. The first pressure sensor 100 may be arranged at the wheel room 10 to detect the wheel room pressure at the wheel room 10, and the second pressure sensor 200 may be arranged at the extraction pipe 80 to detect the extraction pressure at the extraction pipe 80.

[0030] As an example, Figure 2 The schematic diagram of the installation of the first pressure sensor 100 at the wheel chamber 10 is shown.

[0031] like Figure 2 As shown, the first pressure sensor 100 can be disposed on the wheel chamber sidewall on the side opposite to the steam inlet 20 of the wheel chamber 10, specifically, it can be disposed on the other half of the wheel chamber sidewall of the wheel chamber 10 opposite to the half of the wheel chamber sidewall where the steam inlet 20 is located. For example, the steam inlet 20 can be disposed on the upper half of the wheel chamber 10 (such as Figure 1 As shown), the first pressure sensor 100 can be arranged in the lower half wheel chamber 11 (as shown Figure 2 shown).

[0032] There may be multiple first pressure sensors 100, and their specific configuration is as follows: Figure 2 As shown, a plurality of first pressure sensors 100 may be arranged at intervals along the circumference of the wheel chamber 10, and the plurality of first pressure sensors 100 may be located at the same cross section of the wheel chamber as the steam inlet. The plurality of first pressure sensors 100 may be respectively arranged at any position of the wheel chamber, and preferably, the plurality of first pressure sensors 100 may be respectively arranged at different positions in the circumferential direction of the lower half wheel chamber 11. A first pressure sensor mounting structure 300 may be arranged on the side wall of the wheel chamber 10, and the first pressure sensor mounting structure 300 may include an opening 310 and a pipe 320, the opening 310 passes through the side wall of the lower half wheel chamber 11, the pipe 320 is penetrated through the opening 310, and a receiving space is formed inside the pipe 320, and the receiving space is used to install the first pressure sensor 100.

[0033] Return to reference Figure 1 The second pressure sensor 200 may be disposed at the extraction point 81 of the extraction pipe 80 of the extraction steam turbine. There may be a plurality of second pressure sensors 200, and the plurality of second pressure sensors 200 are respectively disposed at the extraction points 81 of the extraction pipe 80 that are different from the steam flow distance of the extraction port 70 of the extraction steam turbine. A second pressure sensor mounting structure (not shown) may be disposed at the extraction point 81 of the extraction pipe 80. The second pressure sensor mounting structure is used to mount the second pressure sensor 200. The second pressure sensor mounting structure may have the same / similar structure as the first pressure sensor mounting structure. The second pressure sensor mounting structure may include an opening penetrating the side wall of the extraction pipe 80 and a pipe penetrating the opening. An accommodation space may be formed inside the pipe. The second pressure sensor 200 may be mounted in the accommodation space of the pipe.

[0034] Figure 3The schematic diagram of the steam flow path of the extraction steam turbine is shown, wherein the arrow indicates the flow direction of the steam flow, ES1 indicates the first expansion section, and ES2 indicates the second expansion section, wherein the first expansion section refers to the component group of the extraction steam turbine through which the steam that has not been extracted flows, and the second expansion section refers to the component group of the extraction steam turbine through which the remaining steam after the extraction flows, for example, the first expansion section ES1 is the area through which the steam flows before the first chamber 51 (including the first chamber 51), and the second expansion section ES2 is the area through which the steam flows after the second chamber 52 (including the second chamber 52). Figure 3 As shown, the extraction steam turbine differential pressure system may further include a pressure transmission device (PT), specifically, may include a first pressure transmission device 110 and a second pressure transmission device 210 .

[0035] like Figure 2 and Figure 3 As shown, the first pressure sensor 100 may be connected to the first pressure transmission device 110 and transmit the detected wheel chamber pressure signal to the first pressure transmission device 110; the second pressure sensor 200 may be connected to the second pressure transmission device 210 and transmit the detected extraction pressure signal to the second pressure transmission device 210. The first pressure transmission device 110 and the second pressure transmission device 210 transmit the wheel chamber pressure from the first pressure sensor 100 and the extraction pressure from the second pressure sensor 200 to the processor 400, respectively.

[0036] In addition, the extraction steam turbine differential pressure system may further include a pressure display instrument (PG) 120, to which the first pressure sensor 100 is connected and sends the detected wheel chamber pressure signal to the pressure display instrument 120, and the pressure display instrument 120 is used to visualize the wheel chamber pressure.

[0037] like Figure 4 As shown, the extraction steam turbine differential pressure system may also include a processor 400, a memory 500 and a controller (not shown). The first pressure sensor 100 and the second pressure sensor 200 are respectively connected to the processor 400, and the detected pressure signal can be transmitted to the processor 400 through the first pressure transmission device 110 and the second pressure transmission device 210. The memory 500 may store a preset safety range. The processor 400 is connected in communication with the first pressure sensor and the second pressure sensor to receive the wheel chamber pressure signal from the first pressure sensor and the extraction pressure signal from the second pressure sensor. The processor 400 is connected in communication with the memory to obtain the preset safety range stored in the memory. The controller is connected in communication with the processor and is connected in communication with the extraction steam turbine to send a control signal to the extraction steam turbine to control the operation or shutdown of the extraction steam turbine.

[0038] Specifically, the processor 400 may call the preset safety range stored in the memory 500, and the preset safety range may include the wheel chamber pressure safety range and the extraction pressure safety range. The processor 400 may compare the wheel chamber pressure and the extraction pressure with the wheel chamber pressure safety range and the extraction pressure safety range, respectively. When at least one of the two does not meet the safety range, a shutdown instruction may be sent to the controller, and the controller controls the steam turbine to shut down; when both meet the safety range, an operation instruction may be sent to the controller, and the controller controls the steam turbine to keep running.

[0039] According to the embodiment of the present application, the differential pressure system of the extraction steam turbine can obtain the turbine chamber pressure and the extraction steam pressure by setting a first pressure sensor and a second pressure sensor to facilitate subsequent control of the steam turbine.

[0040] Another aspect of the present application provides a new method for operating an extraction steam turbine. The method can be executed, for example, by the processor 400 and the controller described above, but the present application is not limited thereto and can also be executed by other existing control devices or systems.

[0041] It is worth noting that before the present application is filed, the safe range of the extraction pressure can be determined according to the fluctuation range of the steam network, and the shutdown operation can be performed when the real-time extraction pressure is outside the safe range. However, this method uses a single-point pressure protection based on the extraction pressure, which may cause frequent shutdowns and affect the stability and economy of the continuous operation of the unit.

[0042] Figures 5 to 7 The working method of an extraction steam turbine according to an embodiment of the present application is shown, and the working method of the extraction steam turbine may include the following operations:

[0043] S1. Obtain the extraction pressure of the extraction pipeline and the turbine chamber pressure of the turbine chamber under the current operating condition of the extraction steam turbine.

[0044] In this step, the extraction steam turbine may be as described above with reference to Figures 1 to 3 As an example, the turbine chamber pressure and the extraction steam pressure can be obtained by the first pressure sensor 100 and the second pressure sensor 200 provided on the lower turbine chamber 11 and the extraction steam pipeline 80 described above.

[0045] S2. Determine whether the extraction steam pressure and turbine chamber pressure meet the preset safety range, and control the extraction steam turbine to operate or shut down according to the determination result.

[0046] In this step, the preset safety range may refer to a range that ensures the normal operation of the extraction steam turbine, which may be predetermined and stored. During the operation of the extraction steam turbine, the preset safety range may be directly called, and the real-time operating data of the extraction steam turbine (specifically, the extraction steam pressure and the turbine chamber pressure) may be compared with the preset safety range to determine whether the extraction steam turbine is in a normal operating state.

[0047] As mentioned above Figure 2 and Figure 3 In the described example, the extraction steam turbine may include a steam inlet, an intermediate steam point, and a steam exhaust port arranged along the flow direction of the steam flow, the steam flow path from the steam inlet to the intermediate steam point forming a first expansion section of the extraction steam turbine, and the steam flow path from the intermediate steam point to the steam exhaust port forming a second expansion section of the extraction steam turbine. Here, the intermediate steam point may be, for example, any point between the first chamber and the second chamber.

[0048] As an example, the preset safety range may be determined based on the extraction pressure safety range and the turbine chamber pressure safety range.

[0049] Specifically, the extraction steam turbine may include a first blade disposed on the steam flow path between the steam inlet and the intermediate steam point and a second blade disposed on the steam flow path between the intermediate steam point and the exhaust port. Here, the first blade and the second blade may be, for example, Figure 1 The drum stage blades 40 are, however, not limited thereto and may also be blades of other forms or functions located in the steam turbine and arranged on the steam flow path.

[0050] As an example, the extraction steam pressure safety range may be determined based on the allowable steam pressure difference range of the second expansion stage and the exhaust steam pressure range of the exhaust port.

[0051] Specifically, the extraction pressure may be the sum of the exhaust pressure and the steam pressure difference of the second expansion section. Here, for the exhaust pressure, when the operating conditions of the extraction steam turbine are determined, the exhaust pressure range of the extraction steam turbine is a determined value, that is, the maximum exhaust pressure and the minimum exhaust pressure of the extraction steam turbine can be determined according to the design of the extraction steam turbine itself, which are usually known parameters in the turbine design process.

[0052] As an example, the extraction steam pressure safety range may be determined in the following manner:

[0053] S211. Determine a maximum allowable value of the steam pressure difference of the second expansion section according to the allowable stress of the second blade.

[0054] In step S211, the allowable stress of the blade refers to the maximum stress that the blade can withstand depending on the inherent characteristics of the blade. Here, the allowable stress of the second blade may be positively correlated with the steam pressure difference of the second expansion section.

[0055] Specifically, the allowable stress of the second blade can be determined based on the inherent characteristics / design parameters of the second blade, thereby determining the maximum allowable value ΔP1 of the steam pressure difference of the second expansion section. max .

[0056] For example, the allowable stress δ1 = k1·ΔP1, where ΔP1 is the steam pressure difference of the second expansion section and k1 is the correlation coefficient, which can be obtained by fitting. max The maximum permissible value of the steam pressure difference of the second expansion stage, ΔP1, can be determined. max .

[0057] S212. Determine the upper limit of the steam extraction pressure safety range according to the maximum allowable value of the steam pressure difference of the second expansion stage and the minimum exhaust pressure of the exhaust pressure range of the exhaust port.

[0058] In step S212, when the extraction steam pressure P E Maximum exhaust steam pressure P A When it is at its minimum, the steam pressure difference ΔP1 before and after the second expansion section (i.e., the difference between the extraction pressure and the exhaust pressure) is the largest, and the steam flow force on the blades is the largest.

[0059] When the steam pressure difference in the second expansion section reaches the maximum allowable steam pressure difference ΔP1 that the blade can withstand, which is determined according to the allowable stress range of the blade max When the exhaust steam pressure P A Minimum, that is, the minimum exhaust pressure P in the exhaust pressure range Amin , then according to the formula P E =P A +ΔP1, can determine the maximum allowable value of extraction steam pressure P Emax , that is, P Emax =P Amin +ΔP1 max .

[0060] S213. Determine the minimum permissible value of the steam pressure difference of the second expansion section according to the allowable temperature of the second blade.

[0061] In step S213, the allowable temperature of the second blade is negatively correlated with the steam pressure difference of the second expansion section.

[0062] Specifically, when the extraction steam turbine is running, when the rotor flow through the second expansion section is small, the blades on the rotor rotate at high speed and stir the surrounding steam. A large amount of mechanical energy is quickly converted into heat energy and heats the air and metal inside the cylinder, causing the rotor and the metal in the cylinder to rise sharply (also known as the blast phenomenon), which may cause damage to parts. Therefore, when the extraction steam pressure is the lowest, it is necessary to avoid too small steam flow in the second expansion section, which will cause abnormal temperature rise or blast phenomenon, so as to determine the minimum extraction steam pressure. In addition, the extraction steam of the steam turbine usually enters the downstream equipment, so the change of the extraction steam pressure does not exceed the pressure tolerance range of the downstream steam pipeline and equipment.

[0063] Therefore, when the temperature of the second blade of the second expansion section rises to the allowable temperature, the minimum steam flow rate allowed in the second expansion section of the extraction steam turbine can be obtained. The minimum steam flow rate allowed in the second expansion section can be positively correlated with the steam pressure difference before and after the rotor of the second expansion section. Therefore, according to the allowable temperature of the second blade, the minimum steam pressure difference ΔP1 of the second expansion section can be obtained. min .

[0064] S214. Determine the lower limit of the steam extraction pressure safety range according to the minimum allowable value of the steam pressure difference of the second expansion stage and the maximum exhaust pressure of the exhaust pressure range of the exhaust port.

[0065] In step S214, when the steam pressure difference of the second expansion section reaches the minimum allowable steam pressure difference ΔP1 that the blade can withstand, which is determined according to the allowable stress range of the blade, min When the exhaust steam pressure P A Maximum, that is, the maximum exhaust pressure P of the exhaust pressure range Amax , then according to the formula P E =P A +ΔP1, the minimum allowable value of extraction steam pressure P can be determined Emin , that is, P Emin =P Amax +ΔP1 min .

[0066] S215. Determine the extraction steam pressure safety range according to the upper limit value and the lower limit value of the extraction steam pressure safety range.

[0067] In step S215, the steam extraction pressure safety line may be determined according to the upper limit and lower limit of the steam extraction pressure safety range, and the steam extraction pressure safety range may be determined according to the steam extraction pressure safety line. Figure 6 As shown, the upper limit value P of the extraction steam pressure safety range can be Emax , determine the upper limit safety line L1 of the extraction pressure; according to the lower limit value P of the extraction pressure safety range Emin , determine the lower limit safety line L2 of the extraction steam pressure.

[0068] As an example, the turbine chamber pressure safety range may be determined based on the extraction steam pressure safety range and the steam pressure difference allowable range of the first expansion stage.

[0069] Specifically, the wheel chamber pressure may be the sum of the extraction pressure and the steam pressure difference of the first expansion stage. As an example, the wheel chamber pressure safety range may be determined in the following manner:

[0070] S221. Determine the maximum permissible value of the steam pressure difference of the first expansion section based on the allowable stress of the first blade and the allowable thrust of the steam turbine.

[0071] In step S221, the first blade refers to the blade located in the first expansion section, the actual stress δ2 of the first blade and the actual thrust F of the steam turbine are both positively correlated with the steam pressure difference ΔP2 of the first expansion section, and the variation range of the actual stress δ2 and the actual thrust F can be determined based on the allowable stress δ2' and the allowable thrust F'. Specifically, the actual stress δ2 is less than or equal to the allowable stress δ2', and the actual thrust F is less than or equal to the allowable thrust F'.

[0072] Here, the allowable stress of the first blade is the maximum stress value that the first blade can withstand when the temperature of the first blade reaches the maximum value of the steam temperature in the first expansion stage, and the allowable thrust of the turbine is the maximum thrust value that the thrust bearing of the turbine unit can withstand.

[0073] Here, the actual stress δ2 = k2·ΔP2, where ΔP2 is the steam pressure difference of the first expansion section, and k2 is the correlation coefficient, which can be obtained by fitting. max , that is, when the actual stress δ2 is equal to the allowable stress δ2', the maximum allowable value ΔP2 of the steam pressure difference in the first expansion section can be determined max .

[0074] The actual thrust of the steam turbine is equal to the product of the steam pressure on the rotor and the axial equivalent area. The first expansion section can be divided into multiple shaft sections. In this case, the actual thrust F can be expressed by the following formula:

[0075]

[0076] Where i represents the i-th shaft segment, i=1,…,n, n is the number of shaft segments in the first expansion segment, ΔP i Indicates the steam pressure difference before and after the i-th shaft section (ΔP i =P i+1 -P i , P i is the steam pressure value after the i-th shaft section, P i+1 is the steam pressure value before the i-th shaft section), Ai represents the equivalent area of ​​the i-th shaft segment. For a steam turbine with a certain structure, the equivalent area A i Therefore, the maximum allowable steam pressure difference ΔP can be calculated based on the maximum value of the actual thrust F being equal to the allowable thrust F' i Here, the actual thrust F can be a function of the extraction pressure, that is, the maximum allowable steam pressure difference ΔP i Related to the extraction pressure, i.e., the maximum allowable value ΔP2 max Extraction steam pressure P E function.

[0077] Based on this, under the combined effect of the actual stress δ2 and the actual thrust F of the first blade, the maximum allowable value ΔP2 calculated based on the actual stress δ2 and the actual thrust F can be calculated as follows: max Take the minimum value to determine the maximum allowable value ΔP2 of the steam pressure difference of the first expansion section under different extraction steam pressures max (P E ).

[0078] S222. Determine the upper limit curve of the turbine chamber pressure safety range according to the maximum allowable value of the steam pressure difference of the first expansion stage and the extraction pressure safety range.

[0079] In step S222, the maximum allowable value ΔP2 of the steam pressure difference of the first expansion section at different extraction steam pressures can be calculated based on the extraction steam pressure safety range determined above. max (P E ), determine the wheel chamber pressure under different extraction steam pressures, and then determine the upper limit curve P of the wheel chamber pressure safety range according to the wheel chamber pressure under different extraction steam pressures Rmax (P E ).

[0080] S223. Determine the minimum permissible value of the steam pressure difference of the first expansion section according to the allowable temperature of the first blade.

[0081] In step S223, the allowable temperature of the first blade is negatively correlated with the steam pressure difference of the first expansion section.

[0082] Specifically, when the extraction steam turbine is running, when the rotor flow rate flowing through the first expansion section is small, the blades on the rotor rotate at high speed and stir the surrounding steam. A large amount of mechanical energy is quickly converted into thermal energy, which heats the air and metal inside the cylinder, causing the temperature of the rotor and the metal in the cylinder to rise sharply (also known as the blast phenomenon), which may cause damage to components.

[0083] Therefore, when the temperature of the first blade of the first expansion section rises to the allowable temperature, the minimum steam flow rate allowed in the first expansion section of the extraction steam turbine can be obtained. The minimum steam flow rate allowed in the first expansion section can be positively correlated with the steam pressure difference before and after the rotor of the first expansion section. Therefore, according to the allowable temperature of the first blade, the minimum steam pressure difference ΔP2 of the first expansion section can be obtained. min .

[0084] S224. Determine a lower limit curve of the turbine chamber pressure safety range according to the minimum allowable value of the steam pressure difference of the first expansion section and the steam extraction pressure safety range.

[0085] In step S224, when the wheel chamber pressure is small, it should be ensured that no air blast occurs in the first expansion section, so as to determine the minimum wheel chamber pressure.

[0086] Specifically, when the steam pressure difference in the first expansion section reaches the minimum allowable steam pressure difference ΔP2 that the blade can withstand, which is determined based on the allowable stress range of the blade, min When, according to the formula P R =P E +ΔP2, can determine the lower limit curve P of the wheel chamber pressure safety range Rmin (P E ), that is, P Rmin (P E )=P E +ΔP2 min .

[0087] S225. Determine the wheel chamber pressure safety range according to the upper limit curve and the lower limit curve of the wheel chamber pressure safety range.

[0088] In step S225, the extraction pressure safety line can be determined based on the upper limit curve and the lower limit curve of the turbine chamber pressure safety range to determine the extraction pressure safety range. Figure 6 As shown, the upper limit curve L3 of the extraction steam pressure safety range and the lower limit curve L4 of the extraction steam pressure safety range can be determined.

[0089] The above describes a specific method for determining the preset safety range. Based on this, it can be determined whether the extraction steam pressure and the turbine chamber pressure meet the preset safety range. Specifically, if Figure 6 As shown, a coordinate system can be established with the extraction pressure as the horizontal coordinate and the turbine chamber pressure as the vertical coordinate. The extraction pressure and turbine chamber pressure obtained during the operation of the steam turbine are formed into coordinates to determine whether the coordinates meet the preset safety range, so as to control the working state of the steam turbine according to the determination result.

[0090] The following will be combined Figure 1 Step S2 and Figure 7The specific operation of controlling the working state of the extraction steam turbine based on the preset safety range is described in detail.

[0091] As an example, in step S2, if Figure 7 As shown, it is possible to determine whether the extraction steam pressure and the wheel chamber pressure meet the preset safety range (S201). If the determination result indicates that the extraction steam pressure and the wheel chamber pressure do not meet the preset safety range, the extraction steam turbine can be controlled to shut down or be in an alarm operation state (S202); if the determination result indicates that the extraction steam pressure and the wheel chamber pressure meet the preset safety range, it is determined whether the extraction steam pressure and the wheel chamber pressure meet the preset safety sub-range (S203) and the extraction steam turbine is controlled to operate or shut down according to the determination result. Here, the preset safety sub-range is smaller than the preset safety range.

[0092] Specifically, when the extraction pressure is greater than the upper limit safety line L1 of the preset extraction pressure or less than the lower limit safety line L2, and / or when the turbine chamber pressure is greater than the upper limit curve L3 of the preset extraction pressure safety range, the extraction steam turbine can be controlled to shut down.

[0093] When the turbine chamber pressure is lower than the lower limit curve L4 of the preset extraction pressure safety range and the extraction pressure is lower than the upper limit safety line L1 of the preset extraction pressure and greater than the lower limit safety line L2, the extraction steam turbine can be controlled to alarm.

[0094] When the extraction steam pressure is less than the upper limit safety line L1 of the preset extraction steam pressure safety range and is greater than the lower limit safety line L2, and the wheel chamber pressure is less than the upper limit curve L3 of the preset wheel chamber pressure safety range and is greater than the lower limit curve L4, that is, the extraction steam pressure and the wheel chamber pressure satisfy the preset safety range, it is further determined whether the extraction steam pressure and the wheel chamber pressure satisfy the preset safety sub-range.

[0095] Here, the preset safety sub-range may refer to a range that ensures that the extraction steam turbine can maintain high-performance operation, and the preset safety sub-range may be determined based on the extraction pressure safety sub-range and the turbine room pressure safety sub-range.

[0096] Specifically, the upper limit value of the extraction pressure safety sub-range may be smaller than the upper limit value of the extraction pressure safety range, so that the upper limit safety line of the extraction pressure (e.g. Figure 6 The lower limit value of the extraction pressure safety sub-range may be greater than the lower limit value of the extraction pressure safety range, so that the lower limit safety line of the extraction pressure can be determined according to the lower limit value of the extraction pressure safety sub-range (such as Figure 6 Here, the safety sub-range of the extraction steam pressure can be determined according to the fluctuation range of the steam network, and the fluctuation range of the steam network here is a range preset by the operator according to the use requirements.

[0097] The upper limit curve of the wheel chamber pressure safety sub-range may be the difference between the upper limit curve L3 of the wheel chamber pressure safety range and the predetermined alarm value, such as Figure 6 As shown, the upper limit curve L7 of the wheel chamber pressure safety sub-range can be obtained by translating the upper limit curve L3 of the wheel chamber pressure safety range downward along the ordinate wheel chamber pressure by a predetermined alarm value, which can be expressed as P Rmax (P E )-Δ, where Δ is a predetermined alarm value, which can be determined according to actual needs. When the wheel chamber pressure satisfies the upper limit curve L3 of the wheel chamber pressure safety range and the upper limit curve L7 of the wheel chamber pressure safety sub-range, an alarm can be issued. The lower limit curve of the wheel chamber pressure safety sub-range can be the lower limit curve L4 of the wheel chamber pressure safety range.

[0098] Based on this, Figure 6 As shown, the preset safety sub-range may be an area enclosed by the extraction pressure safety sub-range (L6, L5) and the wheel chamber pressure safety sub-range (L4, L7).

[0099] Specifically, the steps of judging whether the extraction steam pressure and the wheel chamber pressure satisfy a preset safety sub-range and controlling the operation or shutdown of the extraction steam turbine according to the judgment result may include: when the judgment result indicates that the extraction steam pressure and the wheel chamber pressure do not satisfy the preset safety sub-range, controlling the extraction steam turbine to be in an alarm operation state and issuing an alarm (S204); when the judgment result indicates that the extraction steam pressure and the wheel chamber pressure satisfy the preset safety sub-range, controlling the extraction steam turbine to keep operating (S205).

[0100] Specifically, when the extraction steam pressure and the wheel chamber pressure satisfy the preset safety range, when the extraction steam pressure is greater than the upper limit safety line L5 or less than the lower limit safety line L6 of the preset extraction steam pressure safety sub-range, and / or when the wheel chamber pressure is greater than the upper limit curve L7 of the preset wheel chamber pressure safety sub-range, the extraction steam turbine alarm can be controlled.

[0101] exist Figure 6 In the figure, curve L3 may represent the high wheel room pressure shutdown line, curve L7 may represent the high wheel room pressure alarm line, curve L4 may represent the low wheel room pressure alarm line, curve L1 may represent the high extraction steam pressure shutdown line, curve L5 may represent the high extraction steam pressure alarm line, curve L6 may represent the low extraction steam pressure alarm line, and curve L2 may represent the low extraction steam pressure shutdown line. Specifically, if it is lower than the low wheel room pressure alarm line, it indicates that the unit operating load is too low and is not suitable for long-term operation. Only an alarm reminder will be issued, and no protection action will be triggered. When the extraction steam pressure reaches the alarm line, it reminds that the pressure of the extraction steam network exceeds the operating range, and the unit should be checked and adjusted. When the extraction steam pressure reaches the low shutdown line, it indicates that the pipeline network is seriously abnormal, triggering the unit shutdown protection action. When the extraction steam pressure reaches the high shutdown line, the unit shutdown protection action is triggered.

[0102] As an example, the steps of controlling an extraction steam turbine to be in an alarm operating state and issuing an alarm may include: obtaining the alarm time point of the extraction steam turbine alarm; at a monitoring time point that is a predetermined time apart from the alarm time point, monitoring whether the operating state of the extraction steam turbine is in the alarm operating state, and controlling the operation or shutdown of the extraction steam turbine according to the monitoring result.

[0103] Here, when it is detected at the monitoring time point that the operating state of the extraction steam turbine is in the alarm operating state, the extraction steam turbine is controlled to shut down; when it is detected at the monitoring time point that the extraction steam turbine is not in the alarm operating state, the extraction steam turbine is controlled to keep running. In the alarm operating state, the extraction steam turbine is allowed to keep running, and the alarm needs to be kept to remind the operation and maintenance personnel. Preferably, the predetermined time interval with the alarm time point can be 30 minutes, and the operation or shutdown of the extraction steam turbine is controlled according to the monitoring results.

[0104] In the single-point pressure protection method based on extraction steam pressure, only by judging whether the extraction steam pressure is in the safety range of extraction steam pressure (i.e., whether it is in Figure 6 The steam turbine is controlled to keep running or shut down by setting the alarm operation state according to the embodiment of the present application, and the steam turbine can be allowed to continue to run and alarm when it is close to the shutdown line (for example, when it meets the above-mentioned preset safety range and the preset safety sub-range). Compared with the method of single-point pressure protection based on extraction pressure, which directly shuts down when it is close to the shutdown line, the operation range of the steam turbine is widened, and an alarm can be issued to remind the operation and maintenance personnel. In addition, the alarm operation state can provide the operation and maintenance personnel with sufficient reaction time before the shutdown, and such a method is more in line with the actual operation and maintenance process.

[0105] Although it is described above that the preset safety range and the preset safety sub-range are both determined by the extraction pressure and the wheel chamber pressure, the present application is not limited thereto. The preset safety range and the preset safety sub-range may also be determined by the extraction pressure and the difference between the wheel chamber pressure and the wheel chamber pressure. The determination process may be a parameter transformation based on the above-mentioned operation of determining the preset safety range and the preset safety sub-range. Specifically, Figure 6 The vertical coordinate shown is transformed from the wheel chamber pressure to the difference between the wheel chamber pressure and the wheel chamber pressure. The specific process can be achieved according to the existing mathematical method and will not be repeated here.

[0106] The processor 400, memory 500 and controller of the differential pressure system of the extraction steam turbine according to the embodiment of the present application described above can be implemented as a digital electro-hydraulic control system (DEH) of the extraction steam turbine, and the working method of the extraction steam turbine according to the embodiment of the present application can be executed by the digital electro-hydraulic control system. Specifically, the preset safety range and the preset safety sub-range determined according to the above can be input into the digital electro-hydraulic control system, and the digital electro-hydraulic control system can determine whether the extraction pressure and the wheel chamber pressure meet the preset safety range, and the processing unit of the extraction steam turbine digital electro-hydraulic control system controls the extraction steam turbine to operate or shut down according to the judgment result.

[0107] In addition, the above-mentioned preset safety range and preset safety sub-range (for example, Figure 6 The various curves shown in the figure can be displayed on the display device of the digital electro-hydraulic control system, and the monitoring coordinate points can be generated based on the obtained extraction pressure and turbine room pressure, and displayed superimposed with the preset safety range to intuitively show the current operating status of the steam turbine, thereby realizing real-time dynamic monitoring. Specifically, when the coordinate point position touches the alarm line, the unit alarms, and the operator checks and adjusts the device; when the coordinate point position touches the shutdown line, the unit shutdown is triggered. Figure 6 A point in can have coordinates (P E ,P R ), point A can move within the protection curve as the operating conditions of the steam turbine change. The unit operator can intuitively see the unit operating status on the central control monitoring screen. When the unit is close to the risk area, that is, when point A is close to the alarm line, the unit can be adjusted in advance.

[0108] According to the working method of the extraction steam turbine of the embodiment of the present application, by taking the turbine chamber pressure and the extraction steam pressure as monitoring targets, and taking the thrust condition, operating state, and the strength of the static and rotating parts (e.g., the stress of the blades) of the unit as the basis, a protection mechanism is formulated. Specifically, a preset safety range (e.g., a differential pressure protection curve) can be formulated according to the variable operating characteristics of the steam turbine and external conditions. The preset safety range, on the basis of completely covering the traditional single-point protection interval, broadens the operating range of the unit, improves the operating stability of the device, and can reduce maintenance costs, and has broad application prospects.

[0109] According to the new extraction steam turbine differential pressure system and working method provided in the present application, by judging whether the extraction steam pressure and the turbine chamber pressure meet the preset safety range, the safety state of the extraction steam turbine can be accurately determined, thereby ensuring the safety of the extraction steam turbine operation.

[0110] In addition, according to the new extraction steam turbine differential pressure system and working method provided in the present application, the safe range of operation of the extraction steam turbine is broadened by determining the preset safety range based on the extraction pressure safety range and the turbine chamber pressure safety range, thereby avoiding frequent shutdowns of the unit and ensuring the stability and economy of continuous operation of the unit.

[0111] It should be noted that if the working method of the extraction steam turbine provided by the present application is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a non-volatile computer-readable storage medium that is executable by a processor. Based on this understanding, the technical solution of the present application, or the part that contributes to the prior art, or the part of the technical solution, can be embodied in the form of a software product, which is stored in a storage medium and includes several instructions for a computer device (which can be a personal computer, a server or a network device, etc.) to execute all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM), random access memory (RAM), disk or optical disk, etc., various media that can store program codes.

[0112] Finally, it should be noted that the above-described embodiments are only specific implementation methods of the present application, which are used to illustrate the technical solutions of the present application, rather than to limit them. The protection scope of the present application is not limited thereto. Although the present application is described in detail with reference to the above-mentioned embodiments, ordinary technicians in the field should understand that any technician familiar with the technical field can still modify the technical solutions recorded in the above-mentioned embodiments or easily think of changes, or replace some of the technical features therein with equivalents within the technical scope disclosed in the present application; and these modifications, changes or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application, and should be included in the protection scope of the present application. Therefore, the protection scope of the present application shall be based on the protection scope of the claims.

[0113] Although the present application includes specific examples, it will be clear to those skilled in the art that various changes in form and detail may be made to these examples without departing from the spirit and scope of the claims and their equivalents. The examples described here are considered only in a descriptive sense, not for the purpose of limitation. The description of the features or aspects in each example will be considered to be applicable to similar features or aspects of other examples. If the described techniques are performed in a different order and / or if the components in the described systems, architectures, devices, or circuits are combined in different ways and / or replaced or supplemented by other components or their equivalents, appropriate results may be obtained. Therefore, the scope of the present application is not limited by specific embodiments, but by the claims and their equivalents, and all changes in the scope of the claims and their equivalents will be interpreted as being included in the present application.

Claims

1. A new method for operating an extraction steam turbine, the extraction steam turbine comprising an extraction steam pipeline and a turbine chamber, characterized in that: The novel extraction steam turbine working method comprises: Obtaining the extraction pressure of the extraction pipeline and the turbine chamber pressure of the turbine chamber under the current operating condition of the extraction steam turbine; Determine whether the extraction steam pressure and the turbine chamber pressure meet a preset safety range, and control the extraction steam turbine to operate or shut down according to the determination result; The extraction steam turbine further comprises a steam inlet, an intermediate steam point and a steam exhaust port arranged along the flow direction of the steam flow, the steam flow path from the steam inlet to the intermediate steam point forms a first expansion section of the extraction steam turbine, and the steam flow path from the intermediate steam point to the steam exhaust port forms a second expansion section of the extraction steam turbine, The preset safety range is determined according to the extraction pressure safety range and the turbine chamber pressure safety range, the extraction pressure safety range is determined based on the steam pressure difference allowable range of the second expansion section and the exhaust pressure range of the exhaust port, and the turbine chamber pressure safety range is determined based on the extraction pressure safety range and the steam pressure difference allowable range of the first expansion section; The extraction steam turbine further includes a second blade disposed on the steam flow path between the intermediate steam point and the exhaust port; The extraction steam pressure safety range is determined by: Determining a maximum allowable value of the steam pressure difference of the second expansion section according to the allowable stress of the second blade, wherein the allowable stress of the second blade is positively correlated with the steam pressure difference of the second expansion section; Determine the upper limit of the steam extraction pressure safety range according to the maximum allowable value of the steam pressure difference of the second expansion section and the minimum exhaust pressure of the exhaust pressure range of the exhaust port; Determining a minimum allowable value of the steam pressure difference of the second expansion section according to the allowable temperature of the second blade, wherein the allowable temperature of the second blade is negatively correlated with the steam pressure difference of the second expansion section; Determine the lower limit of the steam extraction pressure safety range according to the minimum allowable value of the steam pressure difference of the second expansion section and the maximum exhaust pressure of the exhaust pressure range of the exhaust port; The steam extraction pressure safety range is determined according to the upper limit value and the lower limit value of the steam extraction pressure safety range.

2. The new extraction steam turbine operating method according to claim 1, characterized in that: The extraction steam turbine further includes a first blade disposed in a steam flow path between the steam inlet and the intermediate steam point; The wheel chamber pressure safety range is determined by: Determining a maximum allowable value of the steam pressure difference of the first expansion section according to the allowable stress and the allowable thrust of the first blade, wherein the allowable stress and the allowable thrust of the first blade are both positively correlated with the steam pressure difference of the first expansion section; Determining an upper limit curve of the turbine chamber pressure safety range according to a maximum allowable value of the steam pressure difference of the first expansion section and the extraction steam pressure safety range; Determining a minimum allowable value of the steam pressure difference of the first expansion section according to the allowable temperature of the first blade and the safety range of the extraction steam pressure, wherein the allowable temperature of the first blade is negatively correlated with the steam pressure difference of the first expansion section; Determining a lower limit curve of the turbine chamber pressure safety range according to the minimum allowable value of the steam pressure difference of the first expansion section and the extraction steam pressure safety range; The wheel chamber pressure safety range is determined according to the upper limit curve and the lower limit curve of the wheel chamber pressure safety range.

3. The new extraction steam turbine operating method according to claim 1, characterized in that: Determining whether the extraction steam pressure and the turbine chamber pressure meet a preset safety range, and controlling the extraction steam turbine to operate or shut down according to the determination result, including: When the judgment result indicates that the extraction steam pressure and the turbine chamber pressure do not meet the preset safety range, the extraction steam turbine is controlled to be shut down or put into an alarm operation state. When the judgment result indicates that the extraction pressure and the wheel chamber pressure satisfy the preset safety range, it is judged whether the extraction pressure and the wheel chamber pressure satisfy the preset safety sub-range, and the operation of the extraction steam turbine is controlled according to the judgment result of whether the extraction pressure and the wheel chamber pressure satisfy the preset safety sub-range, wherein the preset safety sub-range is smaller than the preset safety range.

4. The new extraction steam turbine operating method according to claim 3, characterized in that: Determining whether the extraction steam pressure and the turbine chamber pressure satisfy a preset safety sub-range and controlling the operation of the extraction steam turbine according to the determination result of whether the extraction steam pressure and the turbine chamber pressure satisfy the preset safety sub-range, comprises: When the result of the judgment of whether the extraction steam pressure and the turbine chamber pressure satisfy the preset safety sub-range indicates that the extraction steam pressure and the turbine chamber pressure do not satisfy the preset safety sub-range, controlling the extraction steam turbine to be in an alarm operation state and giving an alarm; When the result of judging whether the extraction steam pressure and the turbine chamber pressure satisfy the preset safety sub-range indicates that the extraction steam pressure and the turbine chamber pressure satisfy the preset safety sub-range, the extraction steam turbine is controlled to keep running.

5. The new extraction steam turbine operating method according to claim 4, characterized in that: Controlling the extraction steam turbine to be in an alarm operation state and giving an alarm, comprising: Obtaining the alarm time point of the extraction steam turbine alarm; At a monitoring time point that is a predetermined time interval from the alarm time point, monitoring whether the operation state of the extraction steam turbine is in the alarm operation state, and controlling the operation or shutdown of the extraction steam turbine according to the monitoring result, Wherein, when it is detected at the monitoring time point that the operation state of the extraction steam turbine is in the alarm operation state, the extraction steam turbine is controlled to shut down; When it is detected at the monitoring time point that the extraction steam turbine is not in the alarm operation state, the extraction steam turbine is controlled to keep operating.

6. A new extraction steam turbine differential pressure system, the extraction steam turbine comprises an extraction steam pipeline and a turbine chamber, characterized in that: The new extraction steam turbine differential pressure system implements the new extraction steam turbine working method as claimed in any one of claims 1 to 5, and the new extraction steam turbine differential pressure system comprises: a first pressure sensor, the first pressure sensor being disposed in a wheel chamber of the extraction steam turbine to detect a wheel chamber pressure of the wheel chamber; a second pressure sensor, the second pressure sensor being disposed in a steam extraction pipeline of the steam extraction turbine to detect a steam extraction pressure of the steam extraction pipeline; A memory storing a preset safety range; a processor, the processor being communicatively connected to the first pressure sensor and the second pressure sensor to receive a wheel chamber pressure signal from the first pressure sensor and an extraction pressure signal from the second pressure sensor, the processor being communicatively connected to the memory to obtain the preset safety range stored in the memory; A controller is communicatively connected to the processor and the extraction steam turbine to send a control signal to the extraction steam turbine for controlling the operation or shutdown of the extraction steam turbine.

7. The new extraction steam turbine differential pressure system according to claim 6, characterized in that: The novel extraction steam turbine differential pressure system further includes a first pressure transmission device and a second pressure transmission device, wherein the first pressure sensor is communicatively connected to the first pressure transmission device, and the second pressure sensor is communicatively connected to the second pressure transmission device, and the first pressure transmission device and the second pressure transmission device transmit the wheel chamber pressure signal and the extraction steam pressure signal to the processor respectively.

8. The novel extraction steam turbine differential pressure system according to claim 6, characterized in that: The novel extraction steam turbine differential pressure system further includes a pressure display instrument, which is communicatively connected to the first pressure sensor to receive the wheel chamber pressure signal from the first pressure sensor and visually display the wheel chamber pressure signal.

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