A drainage optimization method to prevent water ingress to steam turbine caused by shaft seal heater tube burst

Abstract

The present invention discloses a drainage optimization method for preventing water ingress into a steam turbine caused by a shaft seal heater burst, comprising the following steps: (1) modifying the shaft seal heater of a thermal power plant steam turbine thermal system; and (2) modifying the shaft seal inlet steam pipe and / or the shaft seal fan outlet main pipe of the thermal power plant steam turbine thermal system. The drainage optimization method for preventing water ingress into a steam turbine caused by a shaft seal heater burst provided by the present invention, after modification, can monitor the water level of the shaft seal heater in real time online through a remote analog water level gauge, and can control the opening and closing of a corresponding electric door to adjust and control the water level of the shaft seal heater, thereby preventing the shaft seal heater from being filled with water and entering the cylinder; the user can modify the shaft seal inlet steam pipe and the shaft seal fan outlet main pipe according to actual conditions, thereby preventing the shaft seal heater from bursting and causing water ingress into the steam turbine; the technical concept is ingenious and reasonable, the cost is low, and it is suitable for industrial promotion.

Description

Technical Field

[0001] The invention belongs to the technical field of steam turbines, and in particular relates to a drainage optimization method for preventing water ingress into a steam turbine caused by a tube burst of a shaft seal heater. Background Art

[0002] The shaft seal heater in the thermal system of the steam turbine in a thermal power plant is used to recover the heat and working fluid of the return steam of the shaft seal system or the steam leakage at the end of the gate rod, and to heat the condensate at the outlet of the condensate pump. At the same time, the non-condensable gas in the shaft seal heater is extracted by the shaft seal heater exhaust fan, thereby improving the heat exchange effect of the shaft seal heater.

[0003] Since the shaft seal heater is generally arranged in the mezzanine of the turbine plant, which is about 7m higher than the elevation of the turbine operating floor, the water inlet pressure of the shaft seal heater is generally 1.0~2.0MPa, and the corresponding head is 100~200m. The height difference between the low-pressure cylinder shaft seal depression and the shaft seal heater is less than 7m. After the water side pipe of the shaft seal heater bursts, if the emergency water discharge system of the shaft seal heater is improperly designed or has insufficient capacity, it will cause water ingress accident in the low-pressure cylinder of the turbine, which may lead to cylinder deformation, main shaft bending, friction between dynamic and static parts, large vibration shutdown of the unit and other equipment damage or non-shutdown accidents of the unit.

[0004] The information disclosed in this background technology section is only intended to enhance understanding of the overall background of the invention and should not be regarded as an admission or any form of suggestion that the information constitutes the prior art already known to a person skilled in the art. Summary of the Invention

[0005] In order to solve the technical problem of water ingress into the turbine caused by the burst of the shaft seal heater in the thermal system of the existing thermal power plant turbine, the purpose of the present invention is to provide a drainage optimization method to prevent water ingress into the turbine caused by the burst of the shaft seal heater.

[0006] In order to achieve the above-mentioned purpose and the above-mentioned technical effect, the technical solution adopted by the present invention is:

[0007] A drainage optimization method for preventing water ingress to a steam turbine caused by a shaft seal heater tube burst comprises the following steps:

[0008] (1) Renovation of the shaft seal heater of the thermal system of the steam turbine in the thermal power plant;

[0009] (2) Reconstruct the shaft-added steam inlet pipe and / or shaft-added fan outlet main pipe of the thermal system of the thermal power plant.

[0010] In a drainage optimization method for preventing water ingress to a steam turbine caused by a shaft seal heater burst provided by the present invention, in step (1), the step of modifying the shaft seal heater of a thermal system of a steam turbine in a thermal power plant includes:

[0011] A remote analog water level gauge and an electric door for emergency water discharge are added to the shaft seal heater and are connected to the DCS system respectively. The remote analog water level gauge monitors the water level of the shaft seal heater and transmits the information to the DCS system for processing. When the water level monitored by the remote analog water level gauge reaches or exceeds the high threshold water level, the DCS system alarms and controls the electric door for emergency water discharge to open and discharge water, thereby lowering the water level of the shaft seal heater.

[0012] In a drainage optimization method for preventing water ingress to a steam turbine caused by a tube burst of a shaft seal heater provided by the present invention, if the shaft seal heater is not provided with an electric door, an inlet electric door, a water outlet electric door, and a bypass electric door need to be additionally provided. The water inlet side of the shaft seal heater is provided with an inlet electric door, and the water outlet side of the shaft seal heater is provided with a water outlet electric door. The downstream of the water outlet electric door is connected to the upstream of the water inlet electric door through a bypass electric door. The water inlet electric door, the water outlet electric door, and the bypass electric door are respectively connected to a DCS system. The emergency water discharge electric door is provided on the shell side of the shaft seal heater.

[0013] When the water level monitored by the remote analog water level gauge reaches the high threshold water level, the DCS system controls the bypass electric door and the emergency water discharge electric door to open, and closes the water inlet electric door and the water outlet electric door at the same time.

[0014] In a drainage optimization method for preventing water ingress into a steam turbine caused by a shaft seal heater burst provided by the present invention, in step (2), the step of modifying the shaft seal steam inlet pipe of the thermal system of a steam turbine in a thermal power plant includes:

[0015] An emergency water discharge pipe 1 connected to the shaft seal heater is installed at the bottom of the shaft steam inlet pipe. An emergency water discharge electric door 2 is installed on the emergency water discharge pipe 1. The emergency water discharge electric door 2 is connected to the DCS system and controlled by the DCS system. When the remote analog water level gauge monitors the high threshold water level, the DCS system controls the emergency water discharge electric door 2 to open and discharge water.

[0016] In a drainage optimization method for preventing water ingress into a steam turbine caused by a shaft seal heater burst provided by the present invention, in step (2), the shaft seal heater is connected to a shaft fan, and the shaft fan outlet of the shaft fan is located on the roof of the steam turbine main building; the steps of modifying the shaft fan outlet main pipe of the thermal system of the steam turbine of the thermal power plant include:

[0017] The following two transformation modes are designed according to the distance between the shaft fan outlet and the factory wall:

[0018] When the outlet of the shaft fan is close to the factory building wall, the outlet main pipe of the shaft fan should be passed through the main factory building at a height lower than the center of the low-pressure cylinder shaft seal cavity. In the event of a shaft seal heater tube burst, condensate will be discharged from the lower outlet main pipe of the shaft fan to prevent water from entering the turbine.

[0019] When the shaft fan outlet is far away from the factory building wall, an emergency water discharge pipe 2 connected to the shaft seal heater is installed on the shaft fan outlet main pipe, and an emergency water discharge electric door 3 is installed on the emergency water discharge pipe 2. The emergency water discharge electric door 3 is connected to the DCS system and controlled by the DCS system. When the remote water level gauge monitors the high threshold water level, the DCS system controls the emergency water discharge electric door 3 to open and discharge water.

[0020] In a drainage optimization method provided by the present invention for preventing water from entering the turbine due to a shaft seal heater burst, two shaft fans are provided, namely shaft fan A and shaft fan B, and shaft fan A and shaft fan B are respectively connected to the shaft seal heater.

[0021] The present invention also provides a drainage optimization system for preventing water from entering the turbine due to a tube burst in a shaft seal heater. When the shaft seal heater of a thermal system of a steam turbine in a thermal power plant is modified, the system includes a remote analog water level gauge, a water inlet electric door, a water outlet electric door, a bypass electric door, and an emergency water discharge electric door arranged on the shaft seal heater. The emergency water discharge electric door is arranged on the shell side of the shaft seal heater. The water inlet electric door, the water outlet electric door, the bypass electric door, and the emergency water discharge electric door are respectively connected to a DCS system. The DCS system controls the water inlet electric door, the water outlet electric door, the bypass electric door, and the emergency water discharge electric door to achieve interlocking control, thereby preventing water from entering the turbine due to a tube burst in the shaft seal heater.

[0022] The present invention provides a drainage optimization system for preventing water ingress into a steam turbine caused by a shaft seal heater tube burst. When the shaft seal heater steam inlet pipe of a thermal system of a steam turbine in a thermal power plant is modified, the shaft seal heater steam inlet pipe of the system is connected to an emergency water discharge pipe 1, which is arranged at the bottom of the shaft seal heater steam inlet pipe. An emergency water discharge electric door 2 is installed on the emergency water discharge pipe 1. The emergency water discharge electric door 2 is connected to a DCS system and is controlled by the DCS system. When a remote analog water level gauge monitors a high threshold water level, the DCS system controls the emergency water discharge electric door 2 to open and discharge water.

[0023] The present invention provides a drainage optimization system for preventing water ingress into a steam turbine caused by a shaft seal heater burst. When the shaft seal heater of a thermal power plant turbine thermal system is modified, the system's shaft seal heater is connected to shaft seal fans A and B, respectively. When the shaft seal fan outlets of shaft seal fans A and B are close to the plant wall, the shaft seal fan outlet main pipes of the shaft seal fans extend out of the steam turbine main building at a height lower than the center of the low-pressure cylinder shaft seal recess. When the shaft seal fan outlets are far from the plant wall, a drain pipe is installed on the shaft seal fan outlet main pipe, and a main pipe drain electric door is installed on the drain pipe. The emergency drain electric door 3 is connected to and controlled by a DCS system. When a remote water level gauge detects a high threshold water level, the DCS system controls the emergency drain electric door 3 to open and drain water.

[0024] The present invention provides a drainage optimization system for preventing water ingress into a steam turbine caused by a shaft seal heater burst. The inlet steam of the shaft seal heater is respectively connected to the shaft seal return steam of the high-pressure cylinder, the medium-pressure cylinder and the low-pressure cylinder, and the steam leakage at the end of the main and regulating steam valve rods of the steam turbine. The shaft seal heater is connected to the hydrophobic expansion tank through a shaft water seal, the hydrophobic expansion tank is connected to the condenser, the condenser is connected to the condenser hot well, and the condenser hot well is connected to the water inlet electric door through condensate pump A and condensate pump B respectively.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] The present invention discloses a drainage optimization method for preventing water ingress into a steam turbine caused by a shaft seal heater burst, comprising the following steps: modifying the shaft seal heater of a thermal power plant steam turbine thermal system; and modifying the shaft seal steam inlet pipe and / or the shaft seal fan outlet main pipe of the thermal power plant steam turbine thermal system. In the present invention, after the shaft seal heater is modified, the water level of the shaft seal heater can be monitored online in real time through a remote analog water level gauge, and the opening and closing of the corresponding electric door can be controlled to adjust the water level of the shaft seal heater, thereby preventing the shaft seal heater from bursting and causing water ingress into the turbine; after the shaft seal steam inlet pipe and / or the shaft seal fan outlet main pipe are modified, the shaft seal heater from bursting and causing water ingress into the turbine can be avoided; the technical concept is ingenious and reasonable, the cost is low, and it is suitable for industrial promotion. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a structural schematic diagram of the present invention. DETAILED DESCRIPTION

[0028] The present invention is described in detail below so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby making a clearer and more precise definition of the protection scope of the present invention.

[0029] The following is a brief summary of one or more aspects to provide a basic understanding of these aspects. This summary is not an exhaustive overview of all conceivable aspects and is neither intended to identify key or critical elements of all aspects nor to define the scope of any or all aspects. Its sole purpose is to present some concepts of one or more aspects in a simplified form as a prelude to the more detailed description that will be provided later.

[0030] Example 1

[0031] like Figure 1 As shown, the present invention discloses a modification method for preventing water ingress to a steam turbine caused by a tube burst of a shaft seal heater, including the following three modification modes:

[0032] 1) A remote analog water level gauge 12, a water inlet electric door 13, a water outlet electric door 14, a bypass electric door 15 and an emergency water discharge electric door 16 are additionally provided at the shaft seal heater 11. The water inlet electric door 13 is provided on the water inlet side of the shaft seal heater 11, and the water outlet electric door 14 is provided on the water outlet side of the shaft seal heater 11. The downstream of the water outlet electric door 14 is connected to the upstream of the water inlet electric door 13 through the bypass electric door 15. The emergency water discharge electric door 16 is provided on the shell side of the shaft seal heater 11. The remote water level gauge 12, the water inlet electric door 13, the water outlet electric door 14, the bypass electric door 15 and the emergency water discharge electric door 16 are respectively connected to the DCS system and are respectively controlled by the DCS system. The DCS system controls the water inlet electric door 13, the water outlet electric door 14, the bypass electric door 15 and the emergency water discharge electric door 16 to achieve interlocking control. The remote water level gauge 12 is used to monitor the water level of the shaft seal heater 11 and transmit the information to the DCS system for processing. The processing steps of the DCS system are as follows:

[0033] When the water level monitored by the remote analog water level meter 12 reaches or exceeds the high threshold water level, the DCS system triggers the alarm module set thereon to sound an alarm and control the bypass electric door 15 and the emergency water discharge electric door 16 to open, while closing the water inlet electric door 13 and the water outlet electric door 14, and draining water into the ditch I 23 to lower the water level of the shaft seal heater 11.

[0034] 2) Install an emergency water drain pipe 1 at the bottom of the shaft steam inlet pipe, which is connected to the shaft seal heater 11. Install an emergency water drain electric door 2 31 on the emergency water drain pipe 1. The emergency water drain electric door 2 31 is connected to and controlled by the DCS system. When the remote analog water level gauge 12 detects the high threshold water level, the DCS system controls the emergency water drain electric door 2 31 to open and drain water, thereby lowering the water level of the shaft seal heater 11 and preventing water ingress into the turbine due to a pipe burst in the shaft seal heater 11.

[0035] 3) In this embodiment, two axial fans are provided, denoted as axial fans A17 and axial fans B18. When the axial fan outlets 20 of axial fans A17 and axial fans B18 are both located on the roof of the main steam turbine building, the following two modification modes are designed according to the distance between the axial fan outlets 20 and the building wall 19:

[0036] When the axial fan outlet 20 is close to the factory building wall 19, the axial fan outlet main pipe 110 of the axial fan passes through the steam turbine main building at a height lower than the center of the low-pressure cylinder shaft seal cavity. When the shaft seal heater 11 bursts, condensate can be discharged from the lower axial fan outlet main pipe 110 first, preventing water from entering the steam turbine.

[0037] When the shaft fan outlet 20 is far away from the plant wall 19, and it is inconvenient to pass the shaft fan outlet main pipe 110 out of the turbine main plant at a height lower than the center of the low-pressure cylinder shaft seal recess, an emergency water discharge pipe 2 111 is installed on the shaft fan outlet main pipe 110, and an emergency water discharge electric door 3 21 is installed on the emergency water discharge pipe 2 111. The emergency water discharge electric door 3 21 is connected to the DCS and can be remotely controlled by the DCS system. When the remote water level gauge 12 monitors the high threshold water level, the DCS system controls the emergency water discharge electric door 3 21 to open. At this time, the water in the shaft seal heater 11 enters the shaft fan outlet main pipe 110 and the emergency water discharge pipe 2 111 through the shaft fan and is discharged to the ditch I 22.

[0038] The user can adopt only transformation mode 1) or combine it with transformation mode 2) and / or transformation mode 3) according to actual conditions.

[0039] The present invention also discloses a drainage optimization system for preventing water ingress into a steam turbine caused by a shaft seal heater burst. In this system, the steam inlet of the shaft seal heater 11 is connected to the shaft seal return steam of the high-pressure cylinder 1, the intermediate-pressure cylinder 2, and the low-pressure cylinder 3. The high-pressure cylinder front shaft seal 5 and the high-pressure cylinder rear shaft seal 6, the intermediate-pressure cylinder front shaft seal 7 and the intermediate-pressure cylinder rear shaft seal 8, the low-pressure cylinder front shaft seal 9 and the low-pressure cylinder rear shaft seal 10 are respectively performed on the high-pressure cylinder 1, the intermediate-pressure cylinder 2, and the low-pressure cylinder 3. The steam leakage 4 at the end of the main and regulating valve stems of the steam turbine is connected to the shaft seal heater 11.

[0040] 1) When the shaft seal heater 11 of the thermal system of the steam turbine of a thermal power plant is modified, a remote analog water level gauge 12, a water inlet electric door 13, a water outlet electric door 14, a bypass electric door 15 and an emergency water discharge electric door 16 are added to the shaft seal heater 11. Specifically, the water inlet electric door 13 is provided on the water inlet side of the shaft seal heater 11, and the water outlet electric door 14 is provided on the water outlet side of the shaft seal heater 11. The downstream of the water outlet electric door 14 is connected to the upstream of the water inlet electric door 13 through the bypass electric door 15. The shell side of the shaft seal heater 11 is provided with an emergency water discharge electric door 16. The shaft seal heater 11 is connected to the hydrophobic expansion tank 26 through the shaft water seal 24. The drain expansion tank 26 is connected to the condenser 25, the condenser 25 is connected to the condenser hot well 27, the condenser hot well 27 is connected to the water inlet electric door 13 through the condensate pump A28 and the condensate pump B29, the remote water level gauge 12, the water inlet electric door 13, the water outlet electric door 14, the bypass electric door 15 and the emergency water discharge electric door 16 are respectively connected to the DCS system and are respectively controlled by the DCS system. The DCS system controls the water inlet electric door 13, the water outlet electric door 14, the bypass electric door 15 and the emergency water discharge electric door 16 to achieve interlocking control and realize water level alarm, so as to avoid water inflow into the turbine caused by the burst of the shaft seal heater 11.

[0041] The remote analog water level gauge 12 is used to monitor the water level of the shaft seal heater 11 in real time and transmit the information to the DCS system for processing. The processing steps of the DCS system are as follows:

[0042] When the water level monitored by the remote analog water level meter 12 reaches or exceeds the high threshold water level, the DCS system triggers the alarm module set on it to sound an alarm and control the bypass electric door 15 and the emergency water discharge electric door 16 to open, while closing the water inlet electric door 13 and the water outlet electric door 14, draining water into the ditch I 23, and lowering the water level of the shaft seal heater 11.

[0043] 2) When renovating the shaft steam inlet pipe of the thermal system of a thermal power plant's steam turbine, an emergency water discharge pipe 1 connected to the shaft seal heater 11 is installed at the bottom of the shaft steam inlet pipe. An emergency water discharge electric door 2 31 is installed on the emergency water discharge pipe 1. The emergency water discharge electric door 2 31 is connected to and controlled by the DCS. When the remote water level gauge 12 detects a high threshold water level, the DCS controls the emergency water discharge electric door 2 31 to open and discharge water.

[0044] When renovating the main axial fan outlet pipe of a thermal power plant's steam turbine thermal system, the shaft seal heater 11 is also connected to axial fans A17 and B18 in the system. The axial fan outlets 20 of fans A17 and B18 are located on the roof of the steam turbine main building. The following two renovation modes are designed based on the distance between the axial fan outlet 20 and the building wall 19:

[0045] When the axial fan outlet 20 is close to the factory building wall 19, the axial fan outlet main pipe 110 passes through the steam turbine main building at a height lower than the center of the low-pressure cylinder shaft seal cavity. When the shaft seal heater 11 bursts, condensate can be discharged from the lower axial fan outlet main pipe 110 first to prevent water from entering the steam turbine.

[0046] When the shaft fan outlet 20 is far away from the plant wall 19, and it is inconvenient to pass the shaft fan outlet main pipe 110 out of the turbine main plant at a height lower than the center of the low-pressure cylinder shaft seal recess, an emergency water discharge pipe 2 111 is installed on the shaft fan outlet main pipe 110, and an emergency water discharge electric door 3 21 is installed on the emergency water discharge pipe 2 111. The emergency water discharge electric door 3 21 is connected to the DCS and can be remotely controlled by the DCS system. When the remote water level gauge 12 monitors the high threshold water level, the DCS system controls the emergency water discharge electric door 3 21 to open. At this time, the water in the shaft seal heater 11 enters the shaft fan outlet main pipe 110 and the emergency water discharge pipe 2 111 through the shaft fan and is discharged to the ditch I 22.

[0047] Parts or structures not specifically described in the present invention may adopt existing technologies or existing products and will not be described in detail here.

[0048] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A drainage optimization method for preventing water ingress to a steam turbine caused by a shaft seal heater burst, characterized in that: The following steps are involved: (1) Renovation of the shaft seal heater (11) of the thermal system of the steam turbine in a thermal power plant; (2) Reconstruct the shaft-added steam inlet pipe and shaft-added fan outlet main pipe of the thermal system of the thermal power plant; In step (1), the steps of modifying the shaft seal heater (11) of the thermal system of the steam turbine of the thermal power plant include: A remote analog water level gauge (12) and an emergency water discharge electric door (16) are added to the shaft seal heater (11), and the remote analog water level gauge (12) and the emergency water discharge electric door (16) are respectively connected to the DCS system. The remote analog water level gauge (12) monitors the water level of the shaft seal heater (11) and transmits it to the DCS system for processing. When the water level monitored by the remote analog water level gauge (12) reaches or exceeds the high threshold water level, the DCS system alarms and controls the emergency water discharge electric door (16) to open and discharge water, thereby lowering the water level of the shaft seal heater (11); In step (2), the steps of modifying the shaft steam inlet pipe of the thermal system of the steam turbine of the thermal power plant include: An emergency water discharge pipe 1 connected to the shaft seal heater (11) is installed at the bottom of the shaft steam inlet pipe, and an emergency water discharge electric door 2 (31) is installed on the emergency water discharge pipe 1. The emergency water discharge electric door 2 (31) is connected to the DCS system and is controlled by the DCS system. When the remote analog water level meter (12) detects a high threshold water level, the DCS system controls the emergency water discharge electric door 2 (31) to open and discharge water; In step (2), the shaft seal heater (11) is connected to the shaft fan, and the shaft fan outlet (20) of the shaft fan is located on the roof of the steam turbine main building; the steps of modifying the shaft fan outlet main pipe of the thermal system of the steam turbine of the thermal power plant include: The following two transformation modes are designed according to the distance between the shaft fan outlet (20) and the factory wall (19): When the shaft fan outlet (20) is close to the plant wall (19), the shaft fan outlet main pipe (110) is passed through the main plant of the steam turbine at a height lower than the center of the low-pressure cylinder shaft seal cavity. When the shaft seal heater (11) bursts, condensate is discharged from the lower shaft fan outlet main pipe (110) to prevent water from entering the steam turbine. When the shaft fan outlet (20) is far away from the factory building wall (19), an emergency water discharge pipe 2 (111) connected to the shaft seal heater (11) is installed on the shaft fan outlet main pipe (110), and an emergency water discharge electric door 3 (21) is installed on the emergency water discharge pipe 2 (111). The emergency water discharge electric door 3 (21) is connected to the DCS system and is controlled by the DCS system. When the remote water level meter (12) detects the threshold water level, the DCS system controls the emergency water discharge electric door 3 (21) to open and discharge water.

2. The drainage optimization method for preventing water ingress to a steam turbine caused by a shaft seal heater burst according to claim 1, characterized in that: A water inlet electric door (13), a water outlet electric door (14) and a bypass electric door (15) are added to the shaft seal heater (11) that is not equipped with an electric door. The water inlet electric door (13) is provided on the water inlet side of the shaft seal heater (11), and the water outlet electric door (14) is provided on the water outlet side of the shaft seal heater (11). The downstream of the water outlet electric door (14) is connected to the upstream of the water inlet electric door (13) through the bypass electric door (15). The water inlet electric door (13), the water outlet electric door (14) and the bypass electric door (15) are respectively connected to the DCS system. The emergency water discharge electric door (16) is provided on the shell side of the shaft seal heater (11); When the water level monitored by the remote analog water level meter (12) reaches the high threshold water level, the DCS system controls the bypass electric door (15) and the emergency water discharge electric door (16) to open, and simultaneously closes the water inlet electric door (13) and the water outlet electric door (14).

3. The drainage optimization method for preventing water ingress to a steam turbine caused by a shaft seal heater burst according to claim 1, characterized in that: There are two shaft fans, namely shaft fans A (17) and shaft fans B (18), and the shaft fans A (17) and shaft fans B (18) are respectively connected to the shaft seal heater (11).

4. A drainage optimization system using the drainage optimization method for preventing water ingress to a steam turbine caused by a shaft seal heater burst as claimed in claim 1, characterized in that: When the shaft seal heater (11) of the thermal system of the steam turbine of a thermal power plant is modified, the system includes a remote analog water level gauge (12), a water inlet electric door (13), a water outlet electric door (14), a bypass electric door (15) and an emergency water discharge electric door (16) arranged on the shaft seal heater (11), the emergency water discharge electric door (16) being arranged on the shell side of the shaft seal heater (11), the water inlet electric door (13), the water outlet electric door (14), the bypass electric door (15) and the emergency water discharge electric door (16) being connected to the DCS system respectively, and the DCS system controls the water inlet electric door (13), the water outlet electric door (14), the bypass electric door (15) and the emergency water discharge electric door (16) to realize interlocking control, so as to avoid water inflow to the steam turbine caused by the explosion of the shaft seal heater (11).

5. The drainage optimization system for preventing water ingress to a steam turbine caused by a shaft seal heater burst according to claim 4, characterized in that: When the shaft-adding steam inlet pipe of the thermal system of the steam turbine of a thermal power plant is modified, the steam inlet pipe of the shaft seal heater (11) of the system is connected to an emergency water discharge pipe 1, the emergency water discharge pipe 1 is arranged at the bottom of the shaft-adding steam inlet pipe, and the emergency water discharge electric door 2 (31) is installed on the emergency water discharge pipe 1. The emergency water discharge electric door 2 (31) is connected to the DCS system and is controlled by the DCS system. When the remote analog water level meter (12) detects a high threshold water level, the DCS system controls the emergency water discharge electric door 2 (31) to open and discharge water.

6. The drainage optimization system for preventing water ingress to a steam turbine caused by a shaft seal heater burst according to claim 4, characterized in that: When the shaft fan outlet main pipe of the thermal system of the steam turbine of a thermal power plant is modified, the shaft seal heater (11) of the system is connected to the shaft fan A (17) and the shaft fan B (18) respectively. When the shaft fan outlets (20) of the shaft fan A (17) and the shaft fan B (18) are close to the factory building wall (19), the shaft fan outlet main pipe (110) of the shaft fan passes through the main factory building of the steam turbine at a height lower than the center of the low-pressure cylinder shaft seal cavity; when the shaft fan outlets (20) of the shaft fan A (17) and the shaft fan B (18) are close to the factory building wall (19), the shaft fan outlet main pipe (110) of the shaft fan passes through the main factory building of the steam turbine at a height lower than the center of the low-pressure cylinder shaft seal cavity; when the shaft fan When the fan outlet (20) is far away from the factory building wall (19), an emergency water discharge pipe 2 (111) is installed on the shaft-added fan outlet main pipe (110), and an emergency water discharge electric door 3 (21) is installed on the emergency water discharge pipe 2 (111). The emergency water discharge electric door 3 (21) is connected to the DCS system and is controlled by the DCS system. When the remote water level meter (12) detects the threshold water level, the DCS system controls the emergency water discharge electric door 3 (21) to open and discharge water.

7. The drainage optimization system for preventing water ingress to a steam turbine caused by a shaft seal heater burst according to claim 4, characterized in that: The inlet steam of the shaft seal heater (11) is respectively connected to the shaft seal return steam of the high-pressure cylinder (1), the medium-pressure cylinder (2) and the low-pressure cylinder (3) and the steam leakage at the end of the main and regulating steam valve rods of the turbine (4). The shaft seal heater (11) is connected to the hydrophobic expansion tank (26) through the shaft water seal (24). The hydrophobic expansion tank (26) is connected to the condenser (25). The condenser (25) is connected to the condenser hot well (27). The condenser hot well (27) is connected to the water inlet electric door (13) through the condensate pump A (28) and the condensate pump B (29).

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