Steam turbine steam-seal system and control method therefor

Abstract

The present disclosure relates to a turbine steam sealing system and a control method therefor. The turbine steam sealing system includes a steam-sealing steam supply main pipe (1), an auxiliary steam inlet pipe (2), a steam supply regulating valve (3), a heating apparatus (4), and a steam supply parameter measuring apparatus (5). The auxiliary steam inlet pipe (2) is connected to the steam-sealing steam supply main pipe (1). The steam supply regulating valve (3) is connected between the steam-sealing steam supply main pipe (1) and the auxiliary steam inlet pipe (2). The heating apparatus (4) is connected between the auxiliary steam inlet pipe (2) and the steam supply regulating valve (3). The steam supply parameter measuring apparatus (5) is arranged between the heating apparatus (4) and the steam supply regulating valve (3).

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to Chinese Patent Application No. 2023106103301, entitled "STEAM TURBINE STEAM-SEAL SYSTEM AND CONTROL METHOD THEREFOR " and filed on May 26, 2023, the entire contents of which are incorporated herein by reference.TECHNICAL FIELD

[0002] The present disclosure relates to the field of turbine shaft sealing technologies, and in particular to a turbine steam sealing system and a control method therefor.BACKGROUND

[0003] Turbines are widely used in nuclear power units. In order to reduce leakage of steam in a turbine cylinder and prevent leakage of external air into the cylinder, a shaft end of a turbine rotor is provided with shaft-end sealing, referred to as shaft sealing. A turbine steam sealing system is an important part of a turbine, with a main function of providing seal steam for shaft sealing of the turbine to prevent outward leakage of steam in a high-pressure cylinder, so as to ensure high efficiency of the turbine.

[0004] In the startup stage and low-load stage of a turbine, shaft-sealing steam is generally provided by an auxiliary steam system. Unsaturated steam from the auxiliary steam system is heated by an electric heater and then becomes superheated steam with a temperature and pressure meeting requirements. After decompressed by a steam supply regulating valve or a manual bypass valve, the superheated steam enters a steam-sealing steam supply main pipe and is supplied to gland casings of respective cylinders to realize sealing of the cylinders. In a high-load stage, leakage steam from a high-pressure cylinder gland casing, a high-pressure stop valve, and a high-pressure regulating valve is collected by a leakage steam collection pipeline and transferred to the steam-sealing steam supply main pipe to achieve a self-sealing operating condition. Pressure of the steam-sealing steam supply main pipe is regulated jointly by the steam supply regulating valve and an overflow regulating valve that is connected to a condenser. That is, the shaft-sealing steam is provided by the auxiliary steam system in the startup stage and low-load stage of the turbine. In this case, the overflow regulating valve remains closed, and the steam supply regulating valve automatically controls an opening degree to maintain the pressure of the steam-sealing steam supply main pipe. As power rises, leakage steam from the high-pressure cylinder is collected and introduced into the steam-sealing steam supply main pipe, the demand for the opening degree of the steam supply regulating valve gradually decreases until the steam supply regulating valve is completely closed, and then the pressure of the steam-sealing steam supply main pipe is maintained by the overflow regulating valve.

[0005] In an operating condition where the auxiliary steam system supplies steam for sealing, in order to prevent damage to labyrinth teeth and a main shaft due to overtemperature of shaft-sealing steam or entry of wet steam into the gland casing, steam supply parameters are required to be strictly restricted. Once the steam supply parameters exceed a design requirement, the steam supply regulating valve is triggered to be automatically closed, and the turbine may lose steam-sealing steam supply and shaft sealing until the steam supply parameters return to normal.

[0006] In some cases, the turbine steam sealing system has a high requirement for the steam supply parameters, and an envelope range of the steam supply parameters is small, so it is difficult to envelop changes in the steam supply parameters under transient operating conditions. During actual commissioning and operation, the steam supply parameters of the auxiliary steam are easy to exceed the envelope range, resulting in frequent locking of the steam supply regulating valve and frequent triggering of loss of steam-sealing steam supply by the turbine.SUMMARY

[0007] In view of the above problems, the present disclosure provides a turbine steam sealing system and a control method therefor.

[0008] In a first aspect, a turbine steam sealing system includes: a steam-sealing steam supply main pipe; an auxiliary steam inlet pipe connected to the steam-sealing steam supply main pipe; a steam supply regulating valve connected between the steam-sealing steam supply main pipe and the auxiliary steam inlet pipe; a heating apparatus connected between the auxiliary steam inlet pipe and the steam supply regulating valve; and a steam supply parameter measuring apparatus arranged between the heating apparatus and the steam supply regulating valve.

[0009] In an embodiment, the turbine steam sealing system further includes a filtering apparatus, the filtering apparatus being arranged between the steam supply parameter measuring apparatus and the steam supply regulating valve.

[0010] In an embodiment, the steam supply parameter measuring apparatus includes a first temperature measuring assembly and a second temperature measuring assembly, both the first temperature measuring assembly and the second temperature measuring assembly being arranged between the filtering apparatus and the heating apparatus, the first temperature measuring assembly being configured to measure a steam temperature at an outlet of the heating apparatus, and the second temperature measuring assembly being configured to measure a steam temperature in front of the steam supply regulating valve.

[0011] In an embodiment, the first temperature measuring assembly includes a first thermocouple and a second thermocouple, the first thermocouple and the second thermocouple being located at the outlet of the heating apparatus.

[0012] In an embodiment, the steam supply parameter measuring apparatus further includes a pressure measuring assembly, the pressure measuring assembly being arranged between the filtering apparatus and the heating apparatus and configured to measure steam pressure in front of the steam supply regulating valve.

[0013] In an embodiment, the auxiliary steam inlet pipe is adapted to be connected to a main steam pipe of an auxiliary steam system.

[0014] In an embodiment, the turbine steam sealing system further includes a main-pipe temperature measuring apparatus, the main-pipe temperature measuring apparatus being arranged on the steam-sealing steam supply main pipe and configured to measure a temperature of the steam-sealing steam supply main pipe; and / or the turbine steam sealing system further includes an auxiliary steam inlet valve, the auxiliary steam inlet valve being arranged at an inlet end of the auxiliary steam inlet pipe.

[0015] In an embodiment, the turbine steam sealing system further includes a control apparatus, the control apparatus being in signal connection with the steam supply regulating valve, the heating apparatus, and the steam supply parameter measuring apparatus.

[0016] In an embodiment, the turbine steam sealing system further includes an alarm apparatus, and the control apparatus is in signal connection with the alarm apparatus.

[0017] In an embodiment, the turbine steam sealing system further includes a manual bypass valve, the manual bypass valve being arranged in parallel with the steam supply regulating valve.

[0018] In a second aspect, a turbine steam sealing system control method for the turbine steam sealing system according to any one of the embodiments in the first aspect, the control method including: acquiring a steam temperature in front of the steam supply regulating valve; and controlling the heating apparatus to be turned off in a case that the steam temperature in front of the steam supply regulating valve is greater than a first temperature; and controlling the heating apparatus to be turned on in a case that the steam temperature in front of the steam supply regulating valve is less than a second temperature.

[0019] In an embodiment, the control method further includes: acquiring steam pressure in front of the steam supply regulating valve and a steam superheat degree in front of the steam supply regulating valve; and controlling the steam supply regulating valve to be closed in a case that at least one locking condition is met; wherein the locking conditions include: the steam temperature in front of the steam supply regulating valve being greater than a third temperature; the steam pressure in front of the steam supply regulating valve being greater than set pressure; and the steam superheat degree in front of the steam supply regulating valve being less than a set superheat degree.

[0020] In an embodiment, the first temperature is greater than a set temperature of the heating apparatus, the second temperature is less than the set temperature of the heating apparatus, and the third temperature is greater than the first temperature and the second temperature.

[0021] In an embodiment, the set pressure is greater than steam supply pressure of an auxiliary steam system.

[0022] In an embodiment, the control method further includes: acquiring a temperature of the steam-sealing steam supply main pipe; and controlling an opening degree of the steam supply regulating valve to be less than or equal to a first opening degree in a case that the temperature of the steam-sealing steam supply main pipe is less than a fourth temperature; and in a case that the temperature of the steam-sealing steam supply main pipe is greater than or equal to the fourth temperature, determining that a time length during which the temperature of the steam-sealing steam supply main pipe is greater than or equal to the fourth temperature is greater than a first time length, and controlling the opening degree of the steam supply regulating valve to be a second opening degree.

[0023] The above description is merely a summary of the technical solutions of the present disclosure. In order to have a clearer understanding of the technical means of the present disclosure to enable the implementation according to the content of the specification, and in order to make the above and other objectives, features, and advantages of the present disclosure more apparent and understandable, specific implementations of the present disclosure are provided below.BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions in embodiments of the present disclosure, the accompanying drawings used in the description of the embodiments of the present disclosure will be briefly introduced below. It is apparent that, the accompanying drawings in the following description are only some embodiments of the present disclosure, and other drawings can be obtained by those of ordinary skill in the art from the provided drawings without creative efforts. In the drawings, FIG. 1 is a schematic structural diagram of a turbine steam sealing system according to an embodiment of the present disclosure; FIG. 2 is a schematic structural diagram of the turbine steam sealing system to which steam is supplied by auxiliary steam according to an embodiment of the present disclosure; FIG. 3 is a schematic structural diagram of the turbine steam sealing system to which steam is supplied by auxiliary steam according to another embodiment of the present disclosure; FIG. 4 is a first flowchart of a turbine steam sealing system control method according to an embodiment of the present disclosure; FIG. 5 is a second flowchart of the turbine steam sealing system control method according to an embodiment of the present disclosure; and FIG. 6 is a third flowchart of the turbine steam sealing system control method according to an embodiment of the present disclosure. Reference signs:

[0025] 1: steam-sealing steam supply main pipe; 2: auxiliary steam inlet pipe; 3: steam supply regulating valve; 4: heating apparatus; 5: steam supply parameter measuring apparatus; 51: first temperature measuring assembly; 52: second temperature measuring assembly; 6: filtering apparatus; 7: main-pipe temperature measuring apparatus; 8: auxiliary steam inlet valve; 9: manual bypass valve; 200: cylinder; 201: gland casing; 301: main steam pipe. DETAILED DESCRIPTION

[0026] In order to make the above objectives, features, and advantages of the present disclosure more obvious and understandable, specific embodiments of the present disclosure are described in detail below with reference to the accompanying drawings. In the following description, many specific details are set forth in order to fully understand the present disclosure. However, the present disclosure can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without departing from the connotation of the present disclosure. Therefore, the present disclosure is not limited by the specific embodiments disclosed below.

[0027] In the description of the present disclosure, the orientation or position relationships indicated by the terms "central", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like are based on the orientation or position relationships shown in the accompanying drawings and are intended to facilitate the description of the present disclosure and simplify the description only, rather than indicating or implying that the apparatus or element referred to must have a particular orientation or be constructed and operated in a particular orientation, and therefore are not to be interpreted as limiting the present disclosure.

[0028] In addition, the terms "first" and "second" are used for descriptive purposes only, which cannot be construed as indicating or implying a relative importance, or implicitly specifying the number of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more features. In the description of the present disclosure, "a plurality of' means two or more, such as two or three, unless otherwise defined explicitly and specifically.

[0029] In the present disclosure, unless otherwise specified and defined explicitly, the terms "mount", "connect", "join", and "fix" should be understood in a broad sense. For example, they may refer to a fixed connection, a detachable connection, or an integral connection. They may refer to a mechanical connection or an electrical connection. They may refer to a direct connection, an indirect connection via an intermediate medium, an internal connection between two elements, or interaction between two elements. Those of ordinary skill in the art can understand specific meanings of these terms in the present disclosure according to specific situations.

[0030] In the present disclosure, unless otherwise specified and defined explicitly, the expression a first feature being "on" or "under" a second feature may be the case that the first feature is in direct contact with the second feature, or the first feature is in indirect contact with the second feature via an intermediate medium. Furthermore, the expression the first feature being "over", "above" and "on top of' the second feature may be the case that the first feature is directly above or obliquely above the second feature, or only means that the level of the first feature is higher than that of the second feature. The expression the first feature being "below", "underneath" or "under" the second feature may be the case that the first feature is directly underneath or obliquely underneath the second feature, or only means that the level of the first feature is lower than that of the second feature.

[0031] It should be noted that when one element is referred to as "fixed to" or "arranged on" another element, it may be directly disposed on the another element or an intermediate element may exist. When one element is considered to be "connected to" another element, it may be directly connected to the another element or an intermediate element may co-exist. The terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used herein are for illustrative purposes only and do not represent the only implementation.

[0032] HN1188 type steam turbines from Shanghai Electric Group are widely used in domestic pressurized water reactors and Hualong No. 1 nuclear power units. According to a steam sealing system of the turbine, in the startup stage and low-load stage of the turbine, undersaturated steam from an auxiliary steam system is heated by an electric heater and then becomes superheated steam with a temperature and pressure meeting requirements. After decompressed by a steam supply regulating valve or a manual bypass valve, the superheated steam enters a steam-sealing steam supply main pipe and is supplied to gland casings of respective cylinders to realize sealing of the cylinders. In a high-load stage, leakage steam from a high-pressure cylinder gland casing, a high-pressure stop valve, and a high-pressure regulating valve is collected by a leakage steam collection pipeline and transferred to the steam-sealing steam supply main pipe to achieve a self-sealing operating condition. Pressure of the steam-sealing steam supply main pipe is regulated jointly by the steam supply regulating valve and an overflow regulating valve that is connected to a condenser. That is, the shaft-sealing steam is provided by the auxiliary steam system in the startup stage and low-load stage of the turbine. In this case, the overflow regulating valve remains closed, and the steam supply regulating valve automatically controls an opening degree to maintain the pressure of the steam-sealing steam supply main pipe. As power rises, leakage steam from the high-pressure cylinder is collected and introduced into the steam-sealing steam supply main pipe, the demand for the opening degree of the steam supply regulating valve gradually decreases until the steam supply regulating valve is completely closed, and then the pressure of the steam-sealing steam supply main pipe is maintained by the overflow regulating valve.

[0033] In an operating condition where the auxiliary steam system supplies steam for sealing, in order to prevent damage to labyrinth teeth and a main shaft due to overtemperature of steam-sealing steam supply or entry of wet steam into the gland casing, steam supply parameters are strictly restricted by the turbine steam sealing system. Design requirements include: steam pressure in front of the steam supply regulating valve being greater than or equal to 0.3 MPa and less than or equal to 1.1 MPa, a steam temperature in front of the steam supply regulating valve being greater than or equal to 148 °C and less than or equal to 200 °C, and a steam superheat degree in front of the steam supply regulating valve being greater than or equal to 1 Kelvin (K). The steam superheat degree refers to a difference between an actual temperature of steam and a saturation temperature at the actual pressure of steam.

[0034] It is found during actual commissioning and operation that the steam sealing system of the turbine has high requirements for equality of steam supply parameters of steam-sealing steam, and it is difficult to envelop changes in the steam supply parameters under transient operating conditions. Once the steam supply parameters exceed a tolerance range of any of the above restrictions, the steam supply regulating valve is immediately triggered to be automatically closed, so that the turbine loses steam-sealing steam supply. As a result, the turbine loses shaft sealing until the steam supply parameters return to normal.

[0035] Currently, in order to prevent unpredictable influences of frequent loss of steam-sealing steam supply on the turbine, some nuclear power units actually give up a regulating effect of the steam supply regulating valve on the pressure of the steam-sealing steam supply main pipe, a manual bypass valve should be kept open to some extent during hot operation and later power operation, and measures are taken to keep the manual bypass valve open for a long time and continuously supply steam, so as to prevent loss of steam sealing by the turbine due to unexpected closing of the steam supply regulating valve. For example, after the temperature of the steam-sealing steam supply main pipe reaches 110°C and pipe heating ends, a bypass regulating valve is kept about 10% open. However, during normal operation of the turbine, self-sealing is achieved at the shaft sealing, but after the manual bypass valve is opened, the auxiliary steam continuously supplies steam to the steam-sealing steam supply main pipe. As a result, the steam-sealing steam supply main pipe is at an excessively high temperature, which may trigger that an adiabatic expansion value of a low-pressure cylinder rotor of the turbine exceeds a standard. In addition, a purpose of providing the manual bypass valve for the steam supply regulating valve in the turbine is to provide emergency backup in case of failure of the steam supply regulating valve. By manually operating the manual bypass valve, a shaft-sealing steam source can be ensured. When the manual bypass valve is operated with a small opening degree for a long time, the service life of the manual bypass valve may be affected due to a small throttle clearance of the valve and a high flow rate.

[0036] Based on this, for the problem of loss of steam sealing caused by easy and frequency triggering of locking of the steam supply regulating valve by the turbine steam sealing system in some cases, in the present disclosure, starting from a design requirement of the turbine steam sealing system for steam-sealing steam supply parameters, inducements likely to cause the locking of the steam supply regulating valve during actual operation of a turbine unit are screened and identified based on operating parameters and control logic of upstream and downstream systems of the turbine steam sealing system during actual operation, and the turbine steam sealing system is optimized and improved from two aspects of system equipment layout improvement and system control logic optimization, so as to achieve effective and long-term reliable operation of automatic control over steam sealing pressure of the steam supply regulating valve, thereby fundamentally preventing the problem of frequent locking of the steam supply regulating valve in the turbine steam sealing system.

[0037] Referring to FIG. 1 and FIG. 2, FIG. 1 is a schematic structural diagram of a turbine steam sealing system according to an embodiment of the present disclosure, and FIG. 2 is a schematic structural diagram of the turbine steam sealing system to which steam is supplied by auxiliary steam according to an embodiment of the present disclosure. The turbine steam sealing system according to an embodiment of the present disclosure includes a steam-sealing steam supply main pipe 1, an auxiliary steam inlet pipe 2, a steam supply regulating valve 3, a heating apparatus 4, and a steam supply parameter measuring apparatus 5. The auxiliary steam inlet pipe 2 is connected to the steam-sealing steam supply main pipe 1. The steam supply regulating valve 3 is connected between the steam-sealing steam supply main pipe 1 and the auxiliary steam inlet pipe 2. The heating apparatus 4 is connected between the auxiliary steam inlet pipe 2 and the steam supply regulating valve 3. The steam supply parameter measuring apparatus 5 is arranged between the heating apparatus 4 and the steam supply regulating valve 3.

[0038] In this embodiment, the turbine steam sealing system is configured to provide seal steam for shaft sealing and stem steam sealing of the turbine steam sealing system to prevent outward leakage of steam in cylinders 200. Specifically, the steam-sealing steam supply main pipe 1 is connected to gland casings 201 of the cylinders 200, the auxiliary steam inlet pipe 2 is configured to be connected to an auxiliary steam system, and the auxiliary steam inlet pipe 2 and the steam-sealing steam supply main pipe 1 are connected via the steam supply regulating valve 3, so that shaft-sealing steam can be provided by the auxiliary steam system for the steam-sealing steam supply main pipe 1 in the startup stage and low-load stage of the turbine. The heating apparatus 4 is arranged upstream of the steam supply regulating valve 3 on a steam supply path. The heating apparatus 4 is configured to heat undersaturated steam from the auxiliary steam system into superheated steam with a temperature and pressure meeting requirements. The superheated steam is decompressed by the steam supply regulating valve 3 and then enters the steam-sealing steam supply main pipe 1 and is supplied to the gland casings 201 of the cylinders 200 to achieve sealing of the cylinders 200. The steam supply parameter measuring apparatus 5 is configured to measure steam parameters behind the heating apparatus 4 and in front of the steam supply regulating valve 3. It can be determined whether steam-sealing steam supply meets the design requirements according to the steam parameters behind the heating apparatus 4 and in front of the steam supply regulating valve 3, and then an operating state of the heating apparatus 4 and an opening degree of the steam supply regulating valve 3 can be controlled to regulate the steam-sealing steam supply parameters.

[0039] As shown in FIG. 2, when the turbine steam sealing system operates, the auxiliary steam inlet pipe 2 is directly connected to the auxiliary steam system, and the auxiliary steam system supplies auxiliary steam with relatively constant parameters. For example, the auxiliary steam is at a temperature of 188°C and pressure of about 1.1 MPa. The auxiliary steam enters the turbine steam sealing system through the auxiliary steam inlet pipe 2. The heating apparatus 4 superheats the auxiliary steam whose pressure and temperature are relatively stable. The steam supply parameter measuring apparatus 5 performs parameter analysis on the heat-treated auxiliary steam to determine the opening and closing of the steam supply regulating valve 3. The auxiliary steam enters the steam-sealing steam supply main pipe 1 after pressure regulation by the steam supply regulating valve 3. The steam supply regulating valve 3 automatically regulates the opening degree to maintain the pressure of the steam-sealing steam supply main pipe 1. That is, the pressure of the steam-sealing steam supply main pipe 1 is regulated by the steam supply regulating valve 3.

[0040] According to the turbine steam sealing system in the present disclosure, the auxiliary steam inlet pipe 2 is arranged to be directly connected to the auxiliary steam system, and there is no need to provide a pressure regulating valve at an outlet end of the auxiliary steam system, which prevents mutual influences between the pressure regulating valve of the auxiliary steam system and the steam supply regulating valve 3 due to pipeline pressure fluctuations, prevents locking of the steam supply regulating valve 3 caused by the case that a steam superheat degree in front of the steam supply regulating valve 3 does not meet the requirement, prevents joint control of two regulating valves over steam-sealing steam supply pressure, and prevents mutual coupling effects on the two pressure regulating valves, thereby improving reliability of the turbine steam sealing system. The heating apparatus 4 is arranged inside the turbine steam sealing system, there is no need to arrange an electric heater in the auxiliary steam system. The pressure and temperature of the steam heated by the heating apparatus 4 are basically constant, the power output of the heating apparatus 4 is basically stable while ensuring a specified superheat degree, so that the operating environment of the heating apparatus 4 is improved, and there is no need to respond to pressure increasing and pressure reducing of the heated steam, which helps maintain the steam parameters in front of the steam supply regulating valve 3. In addition, through the arrangement of the steam supply parameter measuring apparatus 5, steam supply parameters can be accurately regulated to ensure that the steam supply parameters meet restrictions, which prevents damage to labyrinth teeth and the main shaft due to overtemperature of steam-sealing steam supply or entry of wet steam into the gland casing 201. Moreover, the change of steam supply parameters under transient operating conditions is small, which prevents the steam supply parameters from exceeding the envelope range, meets strict restrictions of the turbine steam sealing system on the steam supply parameters, and prevents loss of steam-sealing steam supply by the turbine caused by triggering of automatic closing of the steam supply regulating valve 3 due to the fact that the steam supply parameters do not meet the design requirement, thereby solving the problem of loss of steam-sealing steam supply by the turbine due to easy and frequency triggering of locking of the steam supply regulating valve by the turbine steam sealing system.

[0041] By using the turbine steam sealing system in the present disclosure, a frequency of occurrence of emergency intervention in hot states after steam admission in the turbine steam sealing system can be effectively reduced, a risk of operators being exposed to steam under hot-state conditions can be significantly reduced, thereby reducing the job risks. Moreover, steam admission protection logic of the turbine steam sealing system is optimized, frequent opening and closing and locking of the steam supply regulating valve 3 are prevented, stability of steam supply in the gland casing 201 is ensured, and the service life of the main shaft of the turbine is prolonged.

[0042] The turbine steam sealing system in the present disclosure may be widely used in turbine units in some cases, such as Shanghai Electric's HN1188 turbines, which greatly improves operational reliability of the turbine steam sealing system without extending a design cycle, purchasing additional equipment, changing a mounting process, or delaying delivery of the system, and is highly cost-effective.

[0043] In some embodiments, the heating apparatus 4 may include an electric heater, and the electric heater performs proportional integral differential (PID) regulation through a built-in programmable logic controller (PLC) control unit, so as to control the heating power of an electric heating wire to regulate an actual value of a temperature of steam heated by the heating apparatus 4 to a set value, thereby realizing automatic control of the heating apparatus 4. For example, the steam temperature in front of the steam supply regulating valve 3 is used as an actual value of PID regulation of the electric heater, and PID regulation is performed through the PLC control unit to achieve a PID regulated set value.

[0044] In some embodiments, the turbine steam sealing system further includes a control apparatus, and the control apparatus is in signal connection with the steam supply regulating valve 3, the heating apparatus 4, and the steam supply parameter measuring apparatus 5. The control apparatus is configured to acquire steam supply parameters collected by the steam supply parameter measuring apparatus 5, and control an operating state of the heating apparatus 4 and opening / closing and an opening degree of the steam supply regulating valve 3 according to the steam supply parameters. The steam supply parameters may include a steam temperature, steam pressure, and a steam superheat degree in front of the steam supply regulating valve 3.

[0045] In some embodiments, the turbine steam sealing system further includes an alarm apparatus, and the control apparatus is in signal connection with the alarm apparatus. The control apparatus may control the alarm apparatus to send an alarm signal when the steam supply regulating valve 3 is closed so as to remind that steam-sealing steam supply is unqualified.

[0046] Referring to FIG. 3, FIG. 3 is a schematic structural diagram of the turbine steam sealing system to which steam is supplied by auxiliary steam according to another embodiment of the present disclosure. In some embodiments, the turbine steam sealing system further includes a filtering apparatus 6, and the filtering apparatus 6 is arranged between the steam supply parameter measuring apparatus 5 and the steam supply regulating valve 3.

[0047] In this embodiment, the filtering apparatus 6 is configured to filter impurities in steam-sealing steam supply, so steam-sealing steam supply is cleaner, which prevents damage to the labyrinth teeth and the main shaft due to entry of the impurities into the gland casing 201 and helps prolong the service life of the main shaft of the turbine. In addition, the steam may be cooled by residual hydrophobic water in the filtering apparatus 6 when flowing through the filtering apparatus 6, so that the steam temperature after hydrophobic cooling in the filtering apparatus 6 is significantly lower than the steam temperature in front of the filtering apparatus 6. The steam supply parameter measuring apparatus 5 is arranged upstream of the filtering apparatus 6 on the steam supply path, which prevents locking of the steam supply regulating valve 3 caused by an excessively high steam temperature at the outlet of the heating apparatus 4 due to the fact that a measured excessively low steam temperature causes the heating apparatus 4 to continuously output power for heating, making the measurement of the steam supply parameters more accurate and regulation of the steam supply parameters more precise, ensuring that the steam supply parameters meet the restrictions, and effectively preventing loss of steam-sealing steam supply by the turbine due to frequent triggering of locking of the steam supply regulating valve.

[0048] In some embodiments, the filtering apparatus 6 may be a Y-type filter.

[0049] In some embodiments, the steam supply parameter measuring apparatus 5 includes a first temperature measuring assembly 51 and a second temperature measuring assembly 52. Both the first temperature measuring assembly 51 and the second temperature measuring assembly 52 are arranged between the filtering apparatus 6 and the heating apparatus 4. The first temperature measuring assembly 51 is configured to measure a steam temperature at an outlet of the heating apparatus 4, and the second temperature measuring assembly 52 is configured to measure a steam temperature in front of the steam supply regulating valve 3.

[0050] In this embodiment, the first temperature measuring assembly 51 measures the steam temperature at the outlet of the heating apparatus 4. A superheat degree of steam-sealing steam supply may be determined according to the steam temperature and steam pressure. A temperature measurement value of the first temperature measuring assembly 51 is used to participate in the determination of a temperature and a superheat degree of steam-sealing steam supply, so as to control the opening and closing of the steam supply regulating valve 3. The second temperature measuring assembly 52 measures the steam temperature in front of the steam supply regulating valve 3. A temperature measurement value of the second temperature measuring assembly 52 is used to participate in regulation of the heating power of the heating apparatus 4, so as to control the output power of the heating apparatus 4. Both the first temperature measuring assembly 51 and the second temperature measuring assembly 52 are arranged upstream of the filtering apparatus 6, which prevents the locking of the steam supply regulating valve 3 caused by a temperature measurement deviation due to the arrangement of the first temperature measuring assembly 51 and the second temperature measuring assembly 52 on two sides of the filtering apparatus 6, making the control over the steam supply regulating valve 3 and the heating apparatus 4 more accurate and the regulation of the steam supply parameters more precise, preventing frequent locking of the steam supply regulating valve 3, and ensuring stability and reliability of steam-sealing steam supply.

[0051] In some embodiments, the first temperature measuring assembly 51 includes a first thermocouple and a second thermocouple. The first thermocouple and the second thermocouple are located at the outlet of the heating apparatus 4. An average temperature measurement value of the first thermocouple and the second thermocouple is used to participate in the determination of the temperature and the superheat degree of steam-sealing steam supply. The second temperature measuring assembly 52 includes a third thermocouple. The third thermocouple is located upstream of the filtering apparatus 6 and near the first thermocouple and the second thermocouple. A temperature measurement value of the third thermocouple is used to regulate heating power of the heating apparatus 4 to prevent locking of the steam supply regulating valve 3 caused by a temperature measurement deviation between the third thermocouple and the first thermocouple as well as the second thermocouple.

[0052] In some embodiments, the steam supply parameter measuring apparatus 5 further includes a pressure measuring assembly (not shown in the figures). The pressure measuring assembly is arranged between the filtering apparatus 6 and the heating apparatus 4 and configured to measure the steam pressure in front of the steam supply regulating valve 3. A saturation temperature of the steam in front of the steam supply regulating valve 3 can be determined according to the steam pressure in front of the steam supply regulating valve 3. A difference between the steam temperature and the saturation temperature in front of the steam supply regulating valve 3 is the steam superheat degree in front of the steam supply regulating valve 3, so that it can be determined whether the superheat degree of steam-sealing steam supply meets the requirement.

[0053] Referring to FIG. 2 and FIG. 3, in some embodiments, the auxiliary steam inlet pipe 2 is configured to be connected to a main steam pipe 301 of the auxiliary steam system. The main steam pipe 301 with a larger volume is connected upstream of the steam supply regulating valve 3, which can reduce sensitivity of steam supply pressure of the auxiliary steam to the opening degree of the steam supply regulating valve 3, preventing a significant influence of rapid opening or closing of the steam supply regulating valve 3 on the steam supply pressure, thereby preventing locking of the steam supply regulating valve 3 caused by reduction of the steam supply pressure to a lower limit due to rapid opening of the steam supply regulating valve 3 and preventing locking of the steam supply regulating valve 3 due to the fact that rapid closing of the steam supply regulating valve 3 causes the steam supply pressure to increase and the saturation temperature in front of the steam supply regulating valve 3 to increase to cause the steam superheat degree in front of the steam supply regulating valve 3 to be less than the lower limit, and ensuring stability and reliability of steam-sealing steam supply.

[0054] Referring to FIG. 1, in some embodiments, the turbine steam sealing system further includes a main-pipe temperature measuring apparatus 7. The main-pipe temperature measuring apparatus 7 is arranged on the steam-sealing steam supply main pipe 1 and configured to measure a temperature of the steam-sealing steam supply main pipe 1. It may be determined according to the temperature of the steam-sealing steam supply main pipe 1 whether the steam-sealing steam supply main pipe 1 reaches a pipe heating requirement, thereby controlling the opening degree of the steam supply regulating valve 3, which helps improve a pipe heating effect.

[0055] Specifically, the control apparatus is in signal connection with the main-pipe temperature measuring apparatus 7, and the control apparatus may acquire the temperature of the steam-sealing steam supply main pipe 1 and controls the opening degree of the steam supply regulating valve 3 according to the temperature of the steam-sealing steam supply main pipe 1.

[0056] Referring to FIG. 2 and FIG. 3, in some embodiments, the turbine steam sealing system further includes an auxiliary steam inlet valve 8. The auxiliary steam inlet valve 8 is arranged at an inlet end of the auxiliary steam inlet pipe 2. The auxiliary steam inlet valve 8 is configured to switch on or switch off the auxiliary steam inlet pipe 2 to connect or disconnect the turbine steam sealing system to or from the auxiliary steam system, thereby starting or stopping supply of auxiliary steam to the turbine steam sealing system.

[0057] Referring to FIG. 2 and FIG. 3, in some embodiments, the turbine steam sealing system further includes a manual bypass valve 9, and the manual bypass valve 9 is arranged in parallel with the steam supply regulating valve 3.

[0058] Referring to FIG. 4, FIG. 4 is a first flowchart of a turbine steam sealing system control method according to an embodiment of the present disclosure. The turbine steam sealing system control method according to an embodiment of the present disclosure is used for the turbine steam sealing system according to any one of the above embodiments. The control method includes the following steps.

[0059] In step S100, a steam temperature in front of the steam supply regulating valve is acquired.

[0060] In step S200, the heating apparatus is controlled to be turned off in a case that the steam temperature in front of the steam supply regulating valve is greater than a first temperature; and the heating apparatus is controlled to be turned on in a case that the steam temperature in front of the steam supply regulating valve is less than a second temperature.

[0061] During the operation of the turbine steam sealing system, if the steam temperature in front of the steam supply regulating valve 3 exceeds an upper limit, the steam supply regulating valve 3 may be locked, thereby resulting in loss of steam-sealing steam supply by the turbine steam sealing system. For example, the upper limit of the steam temperature in front of the steam supply regulating valve 3 may be 200°C. Under a normal operating condition, the auxiliary steam system supplies auxiliary steam with relatively constant parameters. For example, the steam supply parameters of the auxiliary steam system may be a temperature of 188°C and a pressure of about 1.1 MPa. The heating apparatus 4 regulates the heating power according to a difference between the steam temperature in front of the steam supply regulating valve 3 and a set temperature. For example, the set temperature may be 193 °C. The heating apparatus 4 may perform PID regulation through the built-in PLC control unit to regulate the steam temperature at the outlet of the heating apparatus 4 to ensure no occurrence of overheating on the premise of meeting a certain superheat degree. However, because of layout of system equipment, large power of the heating apparatus 4, and certain "inertia" during the heating, etc., if steam supply parameters of the upstream auxiliary steam decrease and thermal inertia of the heating apparatus 4 is large, overshooting of the heating apparatus 4 may occur, resulting in failure of the regulation, and the temperature in front of the steam supply regulating valve 3 may continue to rise and approach 200°C. Failure to intervene in time in this case may result in over-temperature or an insufficient superheat degree, causing locking of the steam supply regulating valve 3 and loss of steam-sealing steam supply.

[0062] In this embodiment, through the setting of the first temperature and the second temperature, the first temperature being used to control the automatic shutdown of the heating apparatus 4, the second temperature being used to control the automatic startup of the heating apparatus 4, an automatic start-stop function of the heating apparatus 4 is realized. Specifically, the steam temperature in front of the steam supply regulating valve 3 is acquired first, and then the steam temperature in front of the steam supply regulating valve 3 is compared with the first temperature and the second temperature respectively. If the steam temperature in front of the steam supply regulating valve 3 is greater than the first temperature, it indicates that the current steam temperature in front of the steam supply regulating valve 3 is already relatively high and is close to an upper temperature limit, in which case the heating apparatus 4 is controlled to be turned off and the heating apparatus 4 is automatically stopped to prevent locking of the steam supply regulating valve 3 caused by overheating of the steam temperature in front of the steam supply regulating valve 3. If the steam temperature in front of the steam supply regulating valve 3 is less than the second temperature, it indicates that the steam temperature in front of the steam supply regulating valve 3 is relatively low, in which case the heating apparatus 4 is controlled to be turned on and the heating apparatus 4 is automatically started to prevent locking of the steam supply regulating valve 3 caused by an insufficient steam superheat degree in front of the steam supply regulating valve 3.

[0063] According to the turbine steam sealing system control method in this embodiment, the control logic of the heating apparatus 4 is optimized, a remote automatic start-stop function of the heating apparatus 4 is realized, operating pressure of the operator under a transient operating condition is reduced, a frequency of occurrence of locking of the steam supply regulating valve 3 is reduced, and operational reliability of the turbine steam sealing system is improved.

[0064] Specifically, the first temperature is greater than a set temperature of the heating apparatus 4, and the second temperature is less than the set temperature of the heating apparatus 4. For example, the set temperature of the heating apparatus 4 may be 193 ° C, the first temperature may be set to 197°C, and the second temperature may be set to 191°C. Then, when the steam temperature in front of the steam supply regulating valve 3 exceeds 197°C, an automatic shutdown instruction is outputted to the heating apparatus 4, and the heating apparatus 4 is automatically shut down. When the steam temperature in front of the steam supply regulating valve 3 decreases to 191°C, an automatic start instruction is outputted to the heating apparatus 4, and the heating apparatus 4 is automatically started.

[0065] Referring to FIG. 5, FIG. 5 is a second flowchart of the turbine steam sealing system control method according to an embodiment of the present disclosure. In some embodiments, the turbine steam sealing system control method further includes the following steps.

[0066] In step S300, a steam pressure in front of the steam supply regulating valve and a steam superheat degree in front of the steam supply regulating valve are acquired.

[0067] In step S400, the steam supply regulating valve is controlled to be closed in a case that at least one locking condition is met; where the locking conditions include: the steam temperature in front of the steam supply regulating valve being greater than a third temperature; the steam pressure in front of the steam supply regulating valve being greater than set pressure; and the steam superheat degree in front of the steam supply regulating valve being less than a set superheat degree.

[0068] In this embodiment, the third temperature, the set pressure, and the set superheat degree are set, the third temperature is an upper limit of a steam-sealing steam supply temperature, the set pressure is an upper limit of a steam-sealing steam supply pressure, and the set superheat degree is a lower limit of a steam-sealing steam supply superheat degree. When steam-sealing steam supply parameters exceed a tolerance range of any of the above restrictions, the steam supply regulating valve 3 is immediately triggered to be automatically closed, causing the turbine steam sealing system to lose steam-sealing steam supply. That is, the locking conditions of the steam supply regulating valve 3 include: the steam temperature in front of the steam supply regulating valve 3 being greater than the third temperature, the steam pressure in front of the steam supply regulating valve 3 being greater than the set pressure, and the steam superheat degree in front of the steam supply regulating valve 3 being less than the set superheat degree. When any one of the above locking conditions is met, locking of the steam supply regulating valve 3 is triggered. Specifically, first, the steam temperature and the steam pressure in front of the steam supply regulating valve 3 are acquired, a steam saturation temperature in front of the steam supply regulating valve 3 may be determined according to the steam pressure in front of the steam supply regulating valve 3, and the steam superheat degree in front of the steam supply regulating valve 3 may be determined according to a difference between the steam temperature and the steam saturation temperature in front of the steam supply regulating valve 3. Then, the steam temperature in front of the steam supply regulating valve 3 is compared with the third temperature, the steam pressure in front of the steam supply regulating valve 3 is compared with the set pressure, and the steam superheat degree in front of the steam supply regulating valve 3 is compared with the set superheat degree. If the steam temperature in front of the steam supply regulating valve 3 is greater than the third temperature, it indicates that the current steam temperature in front of the steam supply regulating valve 3 exceeds the upper limit of the steam-sealing steam supply temperature, in which case the steam supply regulating valve 3 is controlled to be closed. If the steam pressure in front of the steam supply regulating valve 3 is greater than the set pressure, it indicates that the steam pressure in front of the steam supply regulating valve 3 exceeds the upper limit of the steam-sealing steam supply pressure, in which case the steam supply regulating valve 3 is controlled to be closed. If the steam superheat degree in front of the steam supply regulating valve 3 is less than the set superheat degree, it indicates that the steam superheat degree in front of the steam supply regulating valve 3 exceeds the lower limit of the steam-sealing steam supply superheat degree, in which case the steam supply regulating valve 3 is controlled to be closed.

[0069] According to the turbine steam sealing system control method in this embodiment, parameter exceedances that occur frequently during actual operation of the turbine steam sealing system and cause the turbine steam sealing system to lose steam-sealing steam supply are screened, and from a variety of inducements to trigger the locking of the steam supply regulating valve 3, three most easily triggered inducements are identified and screened as the locking conditions, which ensures that the steam-sealing steam supply parameters meet the restrictions, prevents damage to labyrinth teeth and a main shaft due to overtemperature of steam-sealing steam supply or entry of wet steam into the gland casing 201, and optimizes steam admission protection logic of the turbine steam sealing system, thereby preventing frequent opening and closing and locking of the steam supply regulating valve 3, ensuring stability of the steam supply in the gland casing 201, and prolonging the service life of the main shaft of the turbine.

[0070] Specifically, the third temperature is greater than the first temperature and the second temperature.

[0071] In some embodiments, the third temperature may be 200° C. The upper limit of the steam-sealing steam supply temperature is set to 200°C. When the steam temperature in front of the steam supply regulating valve 3 is greater than 200°C, the steam supply regulating valve 3 is triggered to be closed, and the turbine steam sealing system loses steam-sealing steam supply.

[0072] In some embodiments, the set superheat degree may be 1K. The lower limit of the steam-sealing steam supply superheat degree is set to 1K. When the difference between the steam temperature and the saturation temperature in front of the steam supply regulating valve 3 is less than 1K, i.e., the steam superheat degree in front of the steam supply regulating valve 3 is less than 1K, the steam supply regulating valve 3 is triggered to be closed, and the turbine steam sealing system loses steam-sealing steam supply.

[0073] In some embodiments, the set pressure is greater than the steam supply pressure of the auxiliary steam system. For example, under a normal operating condition, the steam supply parameters of the auxiliary steam system are the temperature of 188 °C and the pressure of about 1.1 MPa. If the auxiliary steam system supplies auxiliary steam to the turbine steam sealing system at the pressure of about 1.1 MPa, the set pressure is greater than 1.1 MPa. That is, the upper limit of the steam-sealing steam supply pressure is set to a value above 1.1 MPa, such as 1.15 MPa or 1.2 MPa. When the steam pressure in front of the steam supply regulating valve 3 is greater than the set pressure, the steam supply regulating valve 3 is triggered to be closed, and the turbine steam sealing system loses steam-sealing steam supply.

[0074] In this embodiment, an upper limit of steam supply pressure at which the steam supply regulating valve 3 is locked due to excessive steam supply pressure is greater than the steam supply pressure of the auxiliary steam system, which can effectively prevent a situation where a slight fluctuation in upstream steam supply pressure may lead to locking of the steam supply regulating valve 3, optimize the control logic through which the steam supply pressure triggers locking of the steam supply regulating valve 3, and prevent loss of steam-sealing steam supply by the turbine steam sealing system caused by frequent triggering of locking of the steam supply regulating valve 3. It does not require the arrangement of a pressure regulating valve at the outlet of the auxiliary steam system to depressurize the auxiliary steam, thus simplifying the structure.

[0075] In some embodiments, the turbine steam sealing system control method further includes a step of controlling an alarm apparatus to send an alarm signal when the steam supply regulating valve 3 is closed so as to remind that steam-sealing steam supply is unqualified.

[0076] Referring to FIG. 6, FIG. 6 is a third flowchart of the turbine steam sealing system control method according to an embodiment of the present disclosure. In some embodiments, the turbine steam sealing system control method further includes the following steps.

[0077] In step S500, a temperature of the steam-sealing steam supply main pipe is acquired.

[0078] In step S600, an opening degree of the steam supply regulating valve is controlled to be less than or equal to a first opening degree in a case that the temperature of the steam-sealing steam supply main pipe is less than a fourth temperature; and in a case that the temperature of the steam-sealing steam supply main pipe is greater than or equal to the fourth temperature, it is determined that a time length during which the temperature of the steam-sealing steam supply main pipe is greater than or equal to the fourth temperature is greater than a first time length, and the opening degree of the steam supply regulating valve is controlled to be a second opening degree.

[0079] In this embodiment, through the setting of the fourth temperature and the first time length, the fourth temperature being used to determine whether the temperature of the steam-sealing steam supply main pipe 1 is high or low, the first time length being used to determine a length of pipe heating time of the steam-sealing steam supply main pipe 1, an opening degree of the steam supply regulating valve 3 is controlled according to the temperature and the length of pipe heating time of the steam-sealing steam supply main pipe 1. Specifically, the temperature of the steam-sealing steam supply main pipe 1 is acquired first, and the temperature of the steam-sealing steam supply main pipe 1 is compared with the fourth temperature. Since the steam-sealing steam supply main pipe 1 is required to be heated before the turbine steam sealing system is started, to ensure that a water delivery volume of the steam-sealing steam supply main pipe 1 may not be excessively large during pipe heating in a cold state and a pipe heating effect is improved, when the temperature of the steam-sealing steam supply main pipe 1 is less than the fourth temperature, it indicates that the current temperature of the steam-sealing steam supply main pipe 1 is relatively low and does not meet a pipe heating requirement, in which case the steam supply regulating valve 3 limits the maximum opening degree to a first opening degree. When the temperature of the steam-sealing steam supply main pipe 1 is greater than or equal to the fourth temperature, it indicates that the current temperature of the steam-sealing steam supply main pipe 1 is relatively high and meet the lowest requirement for pipe heating, in which case the time length during which the temperature of the steam-sealing steam supply main pipe 1 is greater than or equal to the fourth temperature is further acquired and the time length during which the temperature of the steam-sealing steam supply main pipe 1 is greater than or equal to the fourth temperature is compared with the first time length. When the time length during which the temperature of the steam-sealing steam supply main pipe 1 is greater than or equal to the fourth temperature is less than or equal to the first time length, it indicates that the current pipe heating time of the steam-sealing steam supply main pipe 1 is relatively short, in which case the steam supply regulating valve 3 keeps limiting the maximum opening degree to the first opening degree, thereby preventing an infinite loop caused by the fact that the opening degree of the steam supply regulating valve 3 causes a flow rate of the steam flow entering the steam-sealing steam supply main pipe 1 to increase rapidly and the temperature of the steam-sealing steam supply main pipe 1 may quickly drop below the fourth temperature due to insufficient pipe heating to trigger the limitation on the first opening degree of the steam supply regulating valve 3. When the time length during which the temperature of the steam-sealing steam supply main pipe 1 is greater than or equal to the fourth temperature is greater than the first time length, it indicates that the current pipe heating time of the steam-sealing steam supply main pipe 1 is relatively long, the pipe heating is more sufficient, and the pipe heating is completed, in which case the steam supply regulating valve 3 unlocks the limitation on the first opening degree, the steam supply regulating valve 3 is controlled to be automatically opened to the second opening degree, and the steam enters the steam-sealing steam supply main pipe 1 to achieve PID regulation on the pressure of the steam-sealing steam supply main pipe 1 with a target value.

[0080] According to the turbine steam sealing system control method in this embodiment, after the temperature of the steam-sealing steam supply main pipe 1 reaches a set pipe heating temperature, pipe heating is forced to be performed for a period of time before the limitation of steam supply regulating valve 3 on the opening degree is released, which ensures sufficient pipe heating of the steam-sealing steam supply main pipe 1, preventing, with the sufficient pipe heating time, a possibility that the temperature of the steam-sealing steam supply main pipe 1 may drop suddenly after the steam supply regulating valve 3 is opened wide, and completely preventing the problem of frequent fluctuations in the opening degree of the steam supply regulating valve 3 during subsequent pipe heating after the improvement.

[0081] In some specific embodiments, when the fourth temperature may be 115°C, the first time length may be 25 minutes, the first opening degree may be 25%, and the second opening degree may be 50% to 60%. When the temperature of the steam-sealing steam supply main pipe 1 is less than 115 °C, the steam supply regulating valve 3 may limit the maximum opening degree to 25%. After the temperature of the steam-sealing steam supply main pipe 1 reaches 115 °C, pipe heating is forced to be performed for 25 minutes before the limitation of steam supply regulating valve 3 on the opening degree is released, and then the steam supply regulating valve 3 is automatically opened to 50% to 60%.

[0082] According to the turbine steam sealing system and the control method therefor in the present disclosure, after 2-month operation verification in a hot-state test period (April 2022 to June 2022) of No. 3 Unit of Fangchenggang Nuclear Power Phase II Project, it is shown that the improvement measures in the present disclosure have significant effects, which can effectively reduce a frequency of occurrence of loss of steam sealing by the turbine due to improper regulation on the steam-sealing steam supply temperature or pressure, provide a better shaft sealing environment for the main shaft of the turbine, and prolong the service life of the main shaft of the turbine.

[0083] The technical features in the above embodiments may be randomly combined. For concise description, not all possible combinations of the technical features in the above embodiments are described. However, all the combinations of the technical features are to be considered as falling within the scope described in this specification provided that they do not conflict with each other.

[0084] The above embodiments only describe several implementations of the present disclosure, and their description is specific and detailed, but cannot therefore be understood as a limitation on the patent scope of the present disclosure. It should be noted that those of ordinary skill in the art may further make variations and improvements without departing from the concept of the present disclosure, and these all fall within the protection scope of the present disclosure. Therefore, the patent protection scope of the present disclosure should be subject to the appended claims.

Claims

1. A turbine steam sealing system, comprising: a steam-sealing steam supply main pipe; an auxiliary steam inlet pipe connected to the steam-sealing steam supply main pipe; a steam supply regulating valve connected between the steam-sealing steam supply main pipe and the auxiliary steam inlet pipe; a heating apparatus connected between the auxiliary steam inlet pipe and the steam supply regulating valve; and a steam supply parameter measuring apparatus arranged between the heating apparatus and the steam supply regulating valve.

2. The turbine steam sealing system according to claim 1, wherein the turbine steam sealing system further comprises a filtering apparatus, the filtering apparatus being arranged between the steam supply parameter measuring apparatus and the steam supply regulating valve.

3. The turbine steam sealing system according to claim 2, wherein the steam supply parameter measuring apparatus comprises a first temperature measuring assembly and a second temperature measuring assembly, both the first temperature measuring assembly and the second temperature measuring assembly being arranged between the filtering apparatus and the heating apparatus, the first temperature measuring assembly being configured to measure a steam temperature at an outlet of the heating apparatus, and the second temperature measuring assembly being configured to measure a steam temperature in front of the steam supply regulating valve.

4. The turbine steam sealing system according to claim 3, wherein the first temperature measuring assembly comprises a first thermocouple and a second thermocouple, the first thermocouple and the second thermocouple being located at the outlet of the heating apparatus.

5. The turbine steam sealing system according to claim 2, wherein the steam supply parameter measuring apparatus further comprises a pressure measuring assembly, the pressure measuring assembly being arranged between the filtering apparatus and the heating apparatus and configured to measure steam pressure in front of the steam supply regulating valve.

6. The turbine steam sealing system according to claim 1, wherein the auxiliary steam inlet pipe is adapted to be connected to a main steam pipe of an auxiliary steam system.

7. The turbine steam sealing system according to claim 1, wherein the turbine steam sealing system further comprises a main-pipe temperature measuring apparatus, the main-pipe temperature measuring apparatus being arranged on the steam-sealing steam supply main pipe and configured to measure a temperature of the steam-sealing steam supply main pipe; and / or the turbine steam sealing system further comprises an auxiliary steam inlet valve, the auxiliary steam inlet valve being arranged at an inlet end of the auxiliary steam inlet pipe.

8. The turbine steam sealing system according to claim 1, wherein the turbine steam sealing system further comprises a control apparatus, the control apparatus being in signal connection with the steam supply regulating valve, the heating apparatus, and the steam supply parameter measuring apparatus.

9. The turbine steam sealing system according to claim 8, wherein the turbine steam sealing system further comprises an alarm apparatus, and the control apparatus is in signal connection with the alarm apparatus.

10. The turbine steam sealing system according to any one of claims 1 to 9, wherein the turbine steam sealing system further comprises a manual bypass valve, the manual bypass valve being arranged in parallel with the steam supply regulating valve.

11. A turbine steam sealing system control method for the turbine steam sealing system according to any one of claims 1 to 10, the control method comprising: acquiring a steam temperature in front of the steam supply regulating valve; and controlling the heating apparatus to be turned off in a case that the steam temperature in front of the steam supply regulating valve is greater than a first temperature; and controlling the heating apparatus to be turned on in a case that the steam temperature in front of the steam supply regulating valve is less than a second temperature.

12. The turbine steam sealing system control method according to claim 11, wherein the control method further comprises: acquiring steam pressure in front of the steam supply regulating valve and a steam superheat degree in front of the steam supply regulating valve; and controlling the steam supply regulating valve to be closed in a case that at least one locking condition is met; wherein the locking conditions comprise: the steam temperature in front of the steam supply regulating valve being greater than a third temperature; the steam pressure in front of the steam supply regulating valve being greater than set pressure; and the steam superheat degree in front of the steam supply regulating valve being less than a set superheat degree.

13. The turbine steam sealing system control method according to claim 12, wherein the first temperature is greater than a set temperature of the heating apparatus, the second temperature is less than the set temperature of the heating apparatus, and the third temperature is greater than the first temperature and the second temperature.

14. The turbine steam sealing system control method according to claim 12, wherein the set pressure is greater than steam supply pressure of an auxiliary steam system.

15. The turbine steam sealing system control method according to claim 11, wherein the control method further comprises: acquiring a temperature of the steam-sealing steam supply main pipe; and controlling an opening degree of the steam supply regulating valve to be less than or equal to a first opening degree in a case that the temperature of the steam-sealing steam supply main pipe is less than a fourth temperature; and in a case that the temperature of the steam-sealing steam supply main pipe is greater than or equal to the fourth temperature, determining that a time length during which the temperature of the steam-sealing steam supply main pipe is greater than or equal to the fourth temperature is greater than a first time length, and controlling the opening degree of the steam supply regulating valve to be a second opening degree.

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