Cylinder connecting device of steam turbine and control method of cylinder connecting device

Abstract

The invention relates to the technical field of steam turbines, and discloses a steam turbine cylinder connecting device and a control method of the steam turbine cylinder connecting device.The steam turbine cylinder connecting device comprises an intermediate-pressure cylinder, a low-pressure cylinder, a first pipeline, a second pipeline and a third pipeline, the intermediate-pressure cylinder is used for being connected with a steam extraction system, and the first pipeline is provided with a first adjusting valve; the second pipeline is provided with a second adjusting valve, and the third pipeline is provided with a third adjusting valve. Wherein the first pipeline, the second pipeline and the third pipeline are respectively connected with the medium-pressure cylinder and the low-pressure cylinder. The steam cylinder connecting device enriches the steam exhaust mode of the medium-pressure cylinder and improves the stability and reliability of operation of the steam turbine.

Description

Technical Field

[0001] This application relates to the technical field of steam turbines, and particularly to a cylinder connection device for a steam turbine and a control method for the cylinder connection device. Background Art

[0002] With the acceleration of the industrialization process and the growth of energy demand, the operating efficiency and safety of steam turbines in heat supply units have become the focus of attention in the power industry. During the operation of steam turbines in heat supply units, the control of the exhaust steam pressure of the intermediate-pressure cylinder is particularly crucial. There are certain limitations and risks in the existing control methods for the exhaust steam pressure of the intermediate-pressure cylinder in steam turbines of heat supply units. Especially after heat supply transformation, the risk of the exhaust steam pressure of the intermediate-pressure cylinder tripping increases, which poses challenges to the stability and reliability of the unit.

[0003] The operating conditions of steam turbines in heat supply units are complex, the exhaust steam states of the cylinder connection device under different operating conditions are complex, the regulation method between the exhaust steam pressure of the intermediate-pressure cylinder and the inlet steam pressure of the low-pressure cylinder is single, and the accuracy and reliability of the regulation are low. Especially in case of emergencies, for example, when the connecting pipeline between the intermediate-pressure cylinder and the low-pressure cylinder is accidentally closed or the heat load suddenly disappears, the exhaust steam pressure of the intermediate-pressure cylinder rapidly rises to the tripping protection setting value, resulting in the unplanned shutdown of the unit, which not only affects the operating efficiency of the unit, but also causes damage to the equipment, increases the maintenance cost and safety hazards. Summary of the Invention

[0004] This application aims to solve at least one of the technical problems existing in the prior art or related technologies.

[0005] In view of this, according to the first aspect of the technical solution of this application, a cylinder connection device for a steam turbine is proposed. The cylinder connection device for the steam turbine includes: an intermediate-pressure cylinder and a low-pressure cylinder, a first pipeline, a second pipeline, and a third pipeline. The intermediate-pressure cylinder is used to connect the extraction steam system. The first pipeline is provided with a first regulating valve, the second pipeline is provided with a second regulating valve, and the third pipeline is provided with a third regulating valve. Among them, the first pipeline, the second pipeline, and the third pipeline are respectively connected to the intermediate-pressure cylinder and the low-pressure cylinder.

[0006] In some technical solutions provided by this application, the cylinder connection device further includes: an outlet pipeline. The inlet end of the outlet pipeline is connected to the intermediate-pressure cylinder, and the outlet end of the outlet pipeline is used to connect the extraction steam system. The outlet pipeline is provided with a first safety valve.

[0007] In some technical solutions provided by this application, the cylinder connection device further includes: a second safety valve. The second safety valve is provided on the outlet pipeline.

[0008] In some technical solutions provided by this application, the cylinder connection device further includes: a pressure sensor. The pressure sensor is provided at the outlet end of the intermediate-pressure cylinder.

[0009] In the second aspect of the technical solution of the present application, a control method for a cylinder connection device is provided. The control method for the cylinder connection device is used for the cylinder connection device provided in any of the above first aspect technical solutions. The control method includes: obtaining the working state of the cylinder connection device; determining the opening and closing states of the first regulating valve, the second regulating valve, and the third regulating valve.

[0010] In some technical solutions provided by the present application, the step of determining the opening and closing states of the first regulating valve, the second regulating valve, and the third regulating valve specifically includes: determining that the working state is a pure condensing condition; controlling the opening degrees of the first regulating valve, the second regulating valve, and the third regulating valve to be 100% respectively.

[0011] In some technical solutions provided by the present application, the step of determining the opening and closing states of the first regulating valve, the second regulating valve, and the third regulating valve specifically includes: determining that the working state is a extraction condensing condition; controlling the first regulating valve and the second regulating valve to open to the same extraction condensing opening degree, the extraction condensing opening degree is associated with the heat load of the extraction steam system, and controlling the third regulating valve to close.

[0012] In some technical solutions provided by the present application, the step of determining the opening and closing states of the first regulating valve, the second regulating valve, and the third regulating valve specifically includes: determining that the working state is a cylinder cutting condition; controlling the first regulating valve and the second regulating valve to close, and controlling the third regulating valve to open to the cylinder cutting opening degree, the cylinder cutting opening degree is associated with the cooling steam amount of the low-pressure cylinder.

[0013] In some technical solutions provided by the present application, after the step of controlling the first regulating valve and the second regulating valve to open to the same extraction condensing opening degree, it further includes: obtaining the working states of the first regulating valve and the second regulating valve, obtaining the exhaust pressure of the intermediate pressure cylinder; determining that the working state of one of the first regulating valve and the second regulating valve is a fault state; controlling the opening degree of the other of the first regulating valve and the second regulating valve to be 100%; determining that the exhaust pressure is greater than the pressure threshold; controlling the opening degree of the first regulating valve and / or the second regulating valve to be 100%.

[0014] In some technical solutions provided by the present application, after the step of obtaining the exhaust pressure of the intermediate pressure cylinder, it further includes: determining that the exhaust pressure is greater than or equal to the relief pressure, and controlling the first safety valve and / or the second safety valve to open; determining that the exhaust pressure is less than or equal to the reseating pressure, and controlling the first safety valve and / or the second safety valve to close.

[0015] Compared with the related art, the present invention has at least the following beneficial effects:

[0016] By setting three connecting pipelines and three regulating valves, the three regulating valves can determine their respective opening and closing states based on the working conditions, enriching the exhaust mode of the intermediate-pressure cylinder. The first regulating valve, the second regulating valve, and the third regulating valve can all control the connection state of the connecting pipeline where they are located according to different working conditions, and then respectively control the steam flow rate in the three connecting pipelines, and control the exhaust steam volume from the intermediate-pressure cylinder to the low-pressure cylinder, so that the intermediate-pressure cylinder can flexibly adjust the exhaust steam volume and exhaust object based on different working conditions, and further realize the stable and reliable steam supply of the cylinder connection device under various working conditions, realize the flexible peak shaving of the steam turbine, and effectively improve the consumption capacity of new energy. Moreover, the number of connecting pipelines is increased. When any one of the connecting pipelines fails, the exhaust steam state of the intermediate-pressure cylinder can be adjusted in time through other connecting pipelines, avoiding the overpressure trip caused by the shutdown of a single pipeline once it fails, reducing the risk of unplanned shutdown caused by the overpressure of the exhaust steam of the intermediate-pressure cylinder, improving the stability and reliability of the operation of the steam turbine, and reducing potential safety hazards. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] By reading the following detailed description of some embodiments, various other advantages and benefits will become clear to those of ordinary skill in the art. The drawings are only for the purpose of showing some embodiments and are not considered to be a limitation of the present application. And throughout the drawings, the same reference numerals are used to represent the same components. In the drawings:

[0018] Figure 1 is a connection schematic diagram of a cylinder connection device according to an embodiment provided by the present application;

[0019] Figure 2 is a flowchart of a control method for a cylinder connection device according to an embodiment provided by the present application.

[0020] Wherein, Figure 1 and Figure 2 the corresponding relationship between the reference numerals and the component names in the drawings is as follows:

[0021] 10 cylinder connection device, 100 intermediate-pressure cylinder, 200 low-pressure cylinder, 300 first pipeline, 310 first regulating valve, 400 second pipeline, 410 second regulating valve, 500 third pipeline, 510 third regulating valve, 600 outlet pipeline, 610 first safety valve, 620 second safety valve, 700 pressure sensor. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0022] In order to better understand the above technical solutions, the technical solutions of the embodiments of the present application will be described in detail below through the drawings and specific embodiments. It should be understood that the specific features in the embodiments of the present application and the embodiments are detailed descriptions of the technical solutions of the embodiments of the present application, rather than limitations on the technical solutions of the present application. Without conflict, the technical features in the embodiments of the present application and the embodiments can be combined with each other.

[0023] An embodiment of the first aspect of the present application provides a cylinder connection device 10 for a steam turbine, as Figure 1 shown. The cylinder connection device 10 of the steam turbine includes: an intermediate pressure cylinder 100 and a low pressure cylinder 200, a first pipeline 300, a second pipeline 400, and a third pipeline 500. The intermediate pressure cylinder 100 is used to connect the extraction steam system. The first pipeline 300 is provided with a first regulating valve 310, the second pipeline 400 is provided with a second regulating valve 410, and the third pipeline 500 is provided with a third regulating valve 510. Among them, the first pipeline 300, the second pipeline 400, and the third pipeline 500 are respectively connected to the intermediate pressure cylinder 100 and the low pressure cylinder 200.

[0024] In this embodiment, the intermediate pressure cylinder 100 and the low pressure cylinder 200 are respectively used to accommodate the steam in the steam turbine. The steam in the intermediate pressure cylinder 100 can enter the extraction steam system to provide heat source for the extraction steam system. The low pressure cylinder 200 can be used for punching extraction steam, zero output of the low pressure cylinder 200, or micro output of the low pressure cylinder 200. The steam pressure in the intermediate pressure cylinder 100 is greater than the steam pressure in the low pressure cylinder 200. There are at least three connecting pipelines between the intermediate pressure cylinder 100 and the low pressure cylinder 200. The connecting pipelines include the first pipeline 300, the second pipeline 400, and the third pipeline 500. The two ends of any connecting pipeline are respectively connected to the intermediate pressure cylinder 100 and the low pressure cylinder 200, so that the steam in the intermediate pressure cylinder 100 can enter the low pressure cylinder 200 through any connecting pipeline.

[0025] A regulating valve is provided on any connecting pipeline. The regulating valve is used to regulate the flow rate in the connecting pipeline. The regulating valve is an EGV (Exhaust Gas Valve, butterfly valve for the intermediate and low pressure connecting pipeline). Specifically, the regulating valves include: a first regulating valve 310, a second regulating valve 410, and a third regulating valve 510. The three regulating valves are respectively arranged on the first pipeline 300, the second pipeline 400, and the third pipeline 500. The regulating valve can regulate the opening degree and control the steam flow rate in the connecting pipeline where it is located through the opening degree. When the opening degree of the regulating valve is 0%, the regulating valve is in the closed state, and the steam in the connecting pipeline where it is located stops flowing. When the opening degree of the regulating valve is 100%, the regulating valve is in the maximum opening state, and the steam in the connecting pipeline where it is located is in the state of maximum flow rate.

[0026] It should be noted that the exhaust steam volume and exhaust steam object of the intermediate pressure cylinder 100 are different under different working conditions. The operator can confirm the working condition through manual operation. The working conditions include pure condensing condition, extraction condensing condition, and cylinder cutting condition.

[0027] By setting three connecting pipelines and three regulating valves, the three regulating valves can determine their respective opening and closing states based on the working conditions, enriching the exhaust mode of the intermediate-pressure cylinder 100. The first regulating valve 310, the second regulating valve 410, and the third regulating valve 510 can all control the connection state of the corresponding connecting pipeline according to different working conditions, and then respectively control the steam flow rate in the three connecting pipelines, and control the exhaust steam volume from the intermediate-pressure cylinder 100 to the low-pressure cylinder 200. Thus, the intermediate-pressure cylinder 100 can flexibly adjust the exhaust steam volume and exhaust object based on different working conditions, and further realize the stable and reliable steam supply of the cylinder connection device 10 under various working conditions, realize the flexible peak shaving of the steam turbine, and effectively improve the consumption capacity of new energy. Moreover, the number of connecting pipelines is increased. When any one of the connecting pipelines fails, the exhaust steam state of the intermediate-pressure cylinder 100 can be adjusted in time through other connecting pipelines, avoiding the situation that the unit trips due to overpressure once a single pipeline fails and closes, reducing the risk of unplanned shutdown caused by overpressure of the exhaust steam of the intermediate-pressure cylinder 100, improving the stability and reliability of the operation of the steam turbine, and reducing potential safety hazards.

[0028] Exemplarily, the first pipeline 300 and the second pipeline 400 have the same pipe diameter.

[0029] Exemplarily, the cylinder connection device 10 further includes a fourth pipeline, and the fourth pipeline is provided with a fourth regulating valve, further enriching the exhaust mode of the intermediate-pressure cylinder 100 and improving the stability and reliability of the operation of the steam turbine.

[0030] In some embodiments provided by the present application, as Figure 1 shown, the cylinder connection device 10 further includes: an outlet pipeline 600, the inlet end of the outlet pipeline 600 is connected to the intermediate-pressure cylinder 100, the outlet end of the outlet pipeline 600 is used for connecting the extraction steam system, and the outlet pipeline 600 is provided with a first safety valve 610.

[0031] In this embodiment, the two ends of the outlet pipeline 600 are respectively connected to the outlet end of the intermediate-pressure cylinder 100 and the extraction steam system. The steam in the intermediate-pressure cylinder 100 enters the extraction steam system through the outlet pipeline 600, and the outlet pipeline 600 is provided with a first safety valve 610.

[0032] Under the extraction-condensing working condition or in case of emergencies, the exhaust steam pressure of the intermediate-pressure cylinder 100 may continue to rise. When the exhaust steam pressure rises above the pressure relief pressure, the first safety valve 610 opens and relieves pressure, discharging the steam in the outlet pipeline 600. It can be understood that when the exhaust steam pressure reaches the turbine trip pressure, the turbine automatically shuts down. The pressure relief pressure is less than the turbine trip pressure, enabling the first safety valve 610 to realize the pressure relief function before the exhaust steam pressure of the intermediate-pressure cylinder reaches the trip protection setting value, avoiding the exhaust steam pressure of the intermediate-pressure cylinder 100 reaching the trip value, thereby reducing the risk of abnormal shutdown of the unit caused by overpressure of the exhaust steam of the intermediate-pressure cylinder and improving the stability and reliability of the operation of the steam turbine.

[0033] After the first safety valve 610 is opened, the exhaust pressure drops. When the exhaust pressure drops below the reseating pressure, the first safety valve 610 reseats, so that the operator can troubleshoot and keep the steam turbine running stably.

[0034] In some embodiments provided by the present application, as Figure 1 shown, the cylinder connection device 10 further includes: a second safety valve 620, and the second safety valve 620 is arranged on the outlet pipeline 600.

[0035] In this embodiment, the second safety valve 620 and the first safety valve 610 are arranged at intervals in the outlet pipeline 600. Two safety valves are arranged in the outlet pipeline 600. That is, when any safety valve fails, the other safety valve can be used for pressure relief to realize the function of the standby safety valve. Also, when the exhaust pressure is too high, the first safety valve 610 and the second safety valve 620 can be used for pressure relief simultaneously, improving the exhaust efficiency, reducing the overpressure risk in the outlet pipeline 600, and improving the safety of the cylinder connection device 10.

[0036] Exemplarily, the first safety valve 610 and the second safety valve 620 are spring-type safety valves.

[0037] In some embodiments provided by the present application, as Figure 1 shown, the cylinder connection device 10 further includes: a pressure sensor 700, and the pressure sensor 700 is arranged at the outlet end of the intermediate pressure cylinder 100.

[0038] In this embodiment, the pressure sensor 700 is used to detect the exhaust pressure of the intermediate pressure cylinder 100 to judge the exhaust state of the intermediate pressure cylinder 100. When the exhaust pressure of the intermediate pressure cylinder 100 is greater than or equal to the pressure threshold, it means that the intermediate pressure cylinder 100 is in an overpressure state. For example, when the thermal load is suddenly lost and the extraction steam system stops extracting steam, the exhaust pressure of the intermediate pressure cylinder 100 rises rapidly, and the first regulating valve 310 and / or the second regulating valve 410 can be fully opened, so that the exhaust of the intermediate pressure cylinder 100 can be discharged into the low-pressure cylinder 200 in time, improving the safety of the operation of the cylinder connection device 10.

[0039] In some embodiments provided by the present application, the cylinder connection device 10 further includes: a first pressure detection member and a second pressure detection member. The first pressure detection member is arranged on the first pipeline 300, and the second pressure detection member is arranged on the second pipeline 400.

[0040] In this embodiment, a first pressure detection component is provided in the first pipeline 300, and a second pressure detection component is provided in the second pipeline 400. The first pressure detection component and the second pressure detection component are respectively used to detect the exhaust steam pressure in the first pipeline 300 and the second pipeline 400, so as to monitor the exhaust steam pressure in the first pipeline 300 and the second pipeline 400, and based on the exhaust steam pressure of the first pipeline 300 and the second pipeline 400, judge the working state of the first regulating valve 310 and the second regulating valve 410 connected. When the exhaust steam pressure of the first pipeline 300 or the second pipeline 400 is greater than or equal to the preset pressure, it indicates that the first pipeline 300 or the second pipeline 400 is in a blocked state, and it is determined that the first regulating valve 310 or the second regulating valve 410 is in a faulty state.

[0041] In some embodiments provided by the present application, the diameter of the third pipeline 500 is smaller than the diameters of the first pipeline 300 and the second pipeline 400.

[0042] In this embodiment, when the working state is the cylinder cutting condition, the first regulating valve 310 and the second regulating valve 410 are closed, and the third regulating valve 510 is opened to the cylinder cutting opening degree, and the size of the cylinder cutting opening degree depends on the amount of cooling steam required by the low-pressure cylinder 200. Since the function of the third pipeline 500 is to ensure that the low-pressure cylinder 200 has an appropriate amount of inlet steam and prevent the low-pressure cylinder 200 from being damaged due to overheating caused by too high temperature. Therefore, the steam output by the third pipeline 500 is relatively less than that of the first pipeline 300 and the second pipeline 400. By limiting the diameter of the third pipeline 500, the material used in the third pipeline 500 is reduced, and the rationality of the pipeline layout is improved.

[0043] In some embodiments provided by the present application, the cylinder connection device 10 further includes: a check valve, and the check valve is provided in the outlet pipeline 600.

[0044] In this embodiment, a check valve is provided in the outlet pipeline 600, and the check valve controls the flow direction of the steam flow in the outlet pipeline 600, so that the steam flows from the intermediate-pressure cylinder 100 to the extraction system, preventing the steam in the outlet pipeline 600 from flowing back, and enabling the intermediate-pressure cylinder 100 to supply steam smoothly.

[0045] In some embodiments provided by the present application, as Figure 1 shown, the first regulating valve 310 and the second regulating valve 410 are manual valves.

[0046] In this embodiment, when the cylinder connection device 10 is in the extraction-condensing condition, when a fault occurs in the first regulating valve 310 or the second regulating valve 410, the operator can manually control the other regulating valve to timely adjust the flow rate in the first pipeline 300 and the second pipeline 400, ensure the flow capacity between the intermediate-pressure cylinder 100 and the low-pressure cylinder 200, and improve the reliability of the equipment operation.

[0047] In some embodiments provided by the present application, such as Figure 1 shown, the third regulating valve 510 is an electric valve.

[0048] In this embodiment, since the opening state of the third regulating valve 510 is relatively stable and the situation of regulating the opening degree is less, therefore, the third regulating valve 510 is set as an electric valve, which improves the control convenience and use stability of the third regulating valve 510.

[0049] In the second aspect embodiment of the present application, a control method for a cylinder connection device is provided. It should be noted that the execution subject of the second aspect embodiment can be a control device of a steam turbine, and this control device can be a functional module and / or a functional entity in the steam turbine, which can be specifically determined according to actual usage requirements. In order to more clearly describe the control method for the cylinder connection device proposed by the present invention, in the following method, the execution subject of the control method for the cylinder connection device is taken as the control device of the steam turbine for exemplary illustration.

[0050] The control method for the cylinder connection device provided by the embodiments of the present application can be used for the cylinder connection device provided in any of the above embodiments of the present application. The cylinder connection device applying the control method of the embodiments of the present application has the specific structure and technical effects in any of the above embodiments of the cylinder connection device.

[0051] Such as Figure 2 shown, the control method for the cylinder connection device is used for the cylinder connection device provided in any of the above first aspect embodiments. The control method includes:

[0052] Step 101, obtaining the working state of the cylinder connection device;

[0053] Step 102, determining the opening and closing states of the first regulating valve, the second regulating valve, and the third regulating valve.

[0054] In this embodiment, the exhaust steam volume and exhaust steam object of the intermediate pressure cylinder are different under different working states. The operator can confirm the working state through manual operation, and the working states include a pure condensing condition, a extraction condensing condition, and a cylinder cutting condition.

[0055] By setting three connecting pipelines and three regulating valves, the three regulating valves can determine their respective opening and closing states based on the working conditions, enriching the exhaust mode of the intermediate-pressure cylinder. The first regulating valve, the second regulating valve, and the third regulating valve can all control the connection state of the connecting pipeline where they are located according to different working conditions, and then respectively control the steam flow rate in the three connecting pipelines, and control the exhaust steam volume from the intermediate-pressure cylinder to the low-pressure cylinder, so that the intermediate-pressure cylinder can flexibly adjust the exhaust steam volume and exhaust object based on different working conditions, and then realize the stable and reliable steam supply of the cylinder connection device under various working conditions, realize the flexible peak shaving of the steam turbine, and effectively improve the consumption capacity of new energy. Moreover, the number of connecting pipelines is increased. When any one of the connecting pipelines fails, the exhaust steam state of the intermediate-pressure cylinder can be adjusted in time through other connecting pipelines, avoiding the overpressure trip caused by the shutdown of a single pipeline once it fails, reducing the risk of unplanned shutdown caused by the overpressure of the exhaust steam of the intermediate-pressure cylinder, improving the stability and reliability of the operation of the steam turbine, and reducing potential safety hazards.

[0056] In some embodiments provided by the present application, the steps of determining the opening and closing states of the first regulating valve, the second regulating valve, and the third regulating valve specifically include: determining that the working condition is a pure condensing condition; controlling the opening degrees of the first regulating valve, the second regulating valve, and the third regulating valve to be 100% respectively.

[0057] In this embodiment, when the working condition is a pure condensing condition, the intermediate-pressure cylinder needs to reduce or stop supplying steam to the extraction steam system and increase the steam inlet volume to the low-pressure cylinder. At this time, the first regulating valve, the second regulating valve, and the third regulating valve are fully opened, so that the opening degrees of the three regulating valves reach the maximum, enabling the intermediate-pressure cylinder to exhaust steam to the low-pressure cylinder through the three connecting pipelines at the same time, increasing the steam inlet volume of the low-pressure cylinder, improving the steam inlet efficiency, and making the exhaust steam state meet the requirements of the pure condensing condition.

[0058] In some embodiments provided by the present application, the steps of determining the opening and closing states of the first regulating valve, the second regulating valve, and the third regulating valve specifically include: determining that the working condition is a extraction condensing condition; controlling the first regulating valve and the second regulating valve to be opened to the same extraction condensing opening degree, and the extraction condensing opening degree is associated with the heat load of the extraction steam system, and controlling the third regulating valve to be closed.

[0059] In this embodiment, when the working condition is a extraction condensing condition, the intermediate-pressure cylinder needs to supply steam to the extraction steam system and the low-pressure cylinder at the same time. At this time, the first regulating valve and the second regulating valve are opened to the same extraction condensing opening degree, so that the first pipeline and the second pipeline evenly divide the flow rate at all times. When any one of the first regulating valve or the second regulating valve fails, the other one can maintain a good flow capacity.

[0060] The opening degree of the extraction-condensing valve depends on the heat load of the extraction-steam supply system. The opening degree of the extraction-condensing valve is inversely related to the load of the extraction-steam system. The greater the heat load, the smaller the opening degree of the extraction-condensing valve, the smaller the flow rates of the first pipeline and the second pipeline, and the less the steam discharged from the intermediate-pressure cylinder to the low-pressure cylinder. Exemplarily, the range of the opening degree of the extraction-condensing valve can be from 10% to 100%.

[0061] Close the third regulating valve to disconnect the third pipeline, so that the intermediate-pressure cylinder discharges steam to the low-pressure cylinder through two connecting pipelines, further reducing the amount of steam discharged from the intermediate-pressure cylinder to the low-pressure cylinder and making the exhaust state meet the requirements of the extraction-condensing condition.

[0062] In some embodiments provided by the present application, the steps of determining the opening and closing states of the first regulating valve, the second regulating valve, and the third regulating valve specifically include: determining that the working state is the cylinder-cutting condition; controlling the first regulating valve and the second regulating valve to close, and controlling the third regulating valve to open to the cylinder-cutting opening degree, and the cylinder-cutting opening degree is associated with the cooling steam amount of the low-pressure cylinder.

[0063] In this embodiment, when the working state is the cylinder-cutting condition, close the first regulating valve and the second regulating valve, and open the third regulating valve to the cylinder-cutting opening degree. The size of the cylinder-cutting opening degree depends on the cooling steam amount required by the low-pressure cylinder. The cylinder-cutting opening degree is positively related to the cooling steam amount. The greater the cooling steam amount, the greater the cylinder-cutting opening degree, the greater the flow rate of the third pipeline, and the more the steam discharged from the intermediate-pressure cylinder to the low-pressure cylinder. Exemplarily, the range of the cylinder-cutting opening degree can be from 10% to 100%. Ensure that the low-pressure cylinder has an appropriate amount of inlet steam to avoid over-temperature damage to the low-pressure cylinder due to excessive temperature.

[0064] The intermediate-pressure cylinder discharges steam to the low-pressure cylinder through the third pipeline, reducing the amount of steam discharged from the intermediate-pressure cylinder to the low-pressure cylinder and making the exhaust state meet the requirements of the cylinder-cutting condition.

[0065] In some embodiments provided by the present application, after the step of controlling the first regulating valve and the second regulating valve to open to the same extraction-condensing opening degree, it further includes: obtaining the working states of the first regulating valve and the second regulating valve, and obtaining the exhaust pressure of the intermediate-pressure cylinder; determining that the working state of one of the first regulating valve and the second regulating valve is a fault state; controlling the opening degree of the other of the first regulating valve and the second regulating valve to be 100%; determining that the exhaust pressure is greater than the pressure threshold; controlling the opening degree of the first regulating valve and / or the second regulating valve to be 100%.

[0066] In this embodiment, under the extraction-condensing condition, based on the exhaust pressure of the intermediate-pressure cylinder and the working states of the first regulating valve and the second regulating valve, determine the exhaust state of the intermediate-pressure cylinder.

[0067] Specifically, both the first regulating valve and the second regulating valve are provided with displacement sensors and travel switches. The displacement sensors are used to detect the opening degrees of the first regulating valve and the second regulating valve, and the travel switches are used to detect the opening states of the first regulating valve and the second regulating valve. The opening states include fully closed and fully open. When the opening degree is 0%, the opening state is fully closed, and when the opening degree is 100%, the opening state is fully open. Based on the opening degree detected by the displacement sensor and the opening state detected by the travel switch, the working states of the first regulating valve and the second regulating valve are determined. When the deviation between the detected opening degree and the preset opening degree is too large and the opening state is fully closed, the working state of the corresponding regulating valve is determined as a fault state.

[0068] When a fault occurs in one of the first regulating valve and the second regulating valve, the other regulating valve remains at a certain opening degree. The other regulating valve is fully opened to 100% opening degree, so that the exhaust steam of the intermediate pressure cylinder can be discharged into the low pressure cylinder in time, improving the flexibility and accuracy of the exhaust steam control of the intermediate pressure cylinder, avoiding overpressure of the intermediate pressure cylinder caused by blockage of the connecting pipeline, and enhancing the safety of the operation of the cylinder connection device.

[0069] When the exhaust steam pressure of the intermediate pressure cylinder is greater than or equal to the pressure threshold, it indicates that the intermediate pressure cylinder is in an overpressure state. For example, when the thermal load suddenly disappears and the extraction steam system stops extracting steam, the exhaust steam pressure of the intermediate pressure cylinder rises rapidly. The first regulating valve and / or the second regulating valve are fully opened, so that the exhaust steam of the intermediate pressure cylinder can be discharged into the low pressure cylinder in time, enhancing the safety of the operation of the cylinder connection device.

[0070] In some embodiments provided by the present application, after the step of obtaining the exhaust steam pressure of the intermediate pressure cylinder, it further includes: determining that the exhaust steam pressure is greater than or equal to the relief pressure, and controlling the first safety valve and / or the second safety valve to open; determining that the exhaust steam pressure is less than or equal to the reseating pressure, and controlling the first safety valve and / or the second safety valve to close.

[0071] In this embodiment, when the exhaust steam pressure of the intermediate pressure cylinder rises above the relief pressure, the first safety valve and / or the second safety valve open and relieve pressure, discharging the steam in the outlet pipeline. It can be understood that when the exhaust steam pressure reaches the turbine trip pressure, the turbine automatically shuts down. The relief pressure is less than the turbine trip pressure, enabling the first safety valve and / or the second safety valve to achieve the pressure relief function before the exhaust steam pressure of the intermediate pressure cylinder reaches the trip protection setting value, avoiding the exhaust steam pressure of the intermediate pressure cylinder reaching the trip value, thereby reducing the risk of abnormal shutdown of the unit caused by overpressure of the exhaust steam pressure of the intermediate pressure cylinder, and improving the stability and reliability of the operation of the turbine.

[0072] After the first safety valve and / or the second safety valve open, the exhaust steam pressure drops. When the exhaust steam pressure drops below the reseating pressure, the first safety valve and / or the second safety valve reseat, so that the operator can check for faults and keep the turbine running stably.

[0073] In a specific embodiment, a control device for preventing overpressure of the exhaust pressure of the intermediate pressure cylinder of the steam turbine of a heating unit is provided to reduce the risk of unplanned shutdown caused by overpressure of the exhaust pressure of the intermediate pressure cylinder of the unit. By adding a bypass to the EGV, it is avoided that when only a single EGV is configured, once the EGV is accidentally closed, the exhaust pressure of the intermediate pressure cylinder rises rapidly and reaches the trip protection set value. By adding a safety valve to the outlet pipeline 600, the pressure relief function is realized before the exhaust pressure of the intermediate pressure cylinder rises rapidly to the trip protection set value, thereby reducing the risk of unplanned shutdown of the unit, solving the existing problem of increased risk of tripping due to the exhaust pressure of the intermediate pressure cylinder caused by heating modification, and improving the stability and reliability of the operation of the heating unit.

[0074] During the specific operation of the medium pressure cylinder exhaust pressure overpressure control device: the first regulating valve 310 is connected as a branch of the second regulating valve 410, and the first regulating valve 310 and the second regulating valve 410 maintain the same opening. Under pure condensation conditions, the first regulating valve 310, the second regulating valve 410, and the third regulating valve 510 are fully opened to 100% opening. Under extraction condensation conditions, the first regulating valve 310 and the second regulating valve 410 maintain the same opening, the size of the opening depends on the heating load, and the third regulating valve 510 is completely closed. Under the cylinder cutting condition, the first regulating valve 310 and the second regulating valve 410 are closed, and the third regulating valve 510 is opened to a certain opening, and the size of the opening depends on the amount of cooling steam required by the low pressure cylinder 200.

[0075] Under the extraction condensation condition, when the first regulating valve 310 or the second regulating valve 410 fails and closes unexpectedly, the second regulating valve 410 or the first regulating valve 310 is still at a certain opening. After the control system determines that the first regulating valve 310 or the second regulating valve 410 has failed, the second regulating valve 410 or the first regulating valve 310 is fully opened to 100% opening. When the heat load is suddenly lost, the steam extraction system no longer extracts steam. At this time, the exhaust pressure of the intermediate pressure cylinder increases rapidly, and the second regulating valve 410 and / or the first regulating valve 310 is fully opened to 100% opening. If during the above process, the exhaust steam pressure of the intermediate pressure cylinder continues to increase and reaches the tripping pressure value of the first safety valve 610 and the second safety valve 620, the first safety valve 610 and the second safety valve 620 will trip to release pressure to keep the exhaust steam pressure of the intermediate pressure cylinder lower than the unit tripping value. After the exhaust steam pressure of the intermediate pressure cylinder drops to the return pressure value of the first safety valve 610 and the second safety valve 620, the first safety valve 610 and the second safety valve 620 will return to their seats. Thereafter, the operating personnel will troubleshoot the fault and keep the unit running stably.

[0076] In the present invention, the terms "first", "second", and "third" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance; the term "plural" refers to two or more, unless otherwise clearly defined. The terms "mounted", "connected", "coupled", "fixed", etc. shall be construed in a broad sense. For example, "connected" may be a fixed connection, a detachable connection, or an integral connection; "coupled" may be a direct connection or an indirect connection through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0077] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "upper", "lower", "left", "right", "front", "rear", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or unit referred to must have a specific direction, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention.

[0078] In the description of this specification, the descriptions of the terms "one embodiment", "some embodiments", "specific embodiments", etc. mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or instance. Moreover, the specific features, structures, materials, or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0079] The above are only some embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A cylinder connection device for a steam turbine, characterized in that, Comprising: An intermediate-pressure cylinder and a low-pressure cylinder, the intermediate-pressure cylinder being used to connect to an extraction steam system; A first pipeline, the first pipeline being provided with a first regulating valve; A second pipeline, the second pipeline being provided with a second regulating valve; A third pipeline, the third pipeline being provided with a third regulating valve; Wherein, the first pipeline, the second pipeline and the third pipeline are respectively connected to the intermediate-pressure cylinder and the low-pressure cylinder.

2. The cylinder connection device according to claim 1, characterized in that, Further comprising: An outlet pipeline, an inlet end of the outlet pipeline being connected to the intermediate-pressure cylinder, an outlet end of the outlet pipeline being used to connect to the extraction steam system, the outlet pipeline being provided with a first safety valve.

3. The cylinder connection device according to claim 2, characterized in that, Further comprising: A second safety valve, the second safety valve being arranged on the outlet pipeline.

4. The cylinder connection device according to claim 1, characterized in that, Further comprising: A pressure sensor, the pressure sensor being arranged at an outlet end of the intermediate-pressure cylinder.

5. A control method for a cylinder connection device, characterized in that, A cylinder connection device for any one of claims 1 to 4, the control method comprising: Obtaining an operating state of the cylinder connection device; Determining opening and closing states of the first regulating valve, the second regulating valve and the third regulating valve.

6. The control method according to claim 5, characterized in that, The step of determining the opening and closing states of the first regulating valve, the second regulating valve and the third regulating valve specifically comprises: Determining that the operating state is a pure condensing condition; Controlling the opening degrees of the first regulating valve, the second regulating valve and the third regulating valve to be 100% respectively.

7. The control method according to claim 5, wherein The step of determining the opening and closing states of the first regulating valve, the second regulating valve and the third regulating valve specifically comprises: Determining that the operating state is a extraction-condensing condition; Controlling the first regulating valve and the second regulating valve to open to the same extraction-condensing opening degree, the extraction-condensing opening degree being associated with a heat load of the extraction steam system, and controlling the third regulating valve to close.

8. The control method according to claim 5, wherein The step of determining the opening and closing states of the first regulating valve, the second regulating valve and the third regulating valve specifically comprises: Determining that the operating state is a cylinder-cutting condition; Controlling the first regulating valve and the second regulating valve to close, and controlling the third regulating valve to open to a cylinder-cutting opening degree, the cylinder-cutting opening degree being associated with a cooling steam amount of the low-pressure cylinder.

9. The control method according to claim 7, wherein After the step of controlling the first regulating valve and the second regulating valve to open to the same extraction-condensing opening degree, further comprising: Obtaining operating states of the first regulating valve and the second regulating valve, and obtaining an exhaust pressure of the intermediate-pressure cylinder; Determining that an operating state of one of the first regulating valve and the second regulating valve is a fault state; Controlling an opening degree of the other of the first regulating valve and the second regulating valve to be 100%; Determining that the exhaust pressure is greater than a pressure threshold; Controlling an opening degree of the first regulating valve and / or the second regulating valve to be 100%.

10. The control method according to claim 9, wherein After the step of obtaining the exhaust pressure of the intermediate-pressure cylinder, further comprising: Determining that the exhaust pressure is greater than or equal to a relief pressure, and controlling the first safety valve and / or the second safety valve to open; Determining that the exhaust pressure is less than or equal to a reseating pressure, and controlling the first safety valve and / or the second safety valve to close.

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