Automatic protection device for extraction steam turbine to throw off heat load

Abstract

The utility model discloses an automatic protection device of extraction steam type steam turbine throws heat load, relates to extraction steam type steam turbine technical field. Including: steam turbine main part, control module, coal mill and boiler, control module and steam turbine main part, coal mill and boiler between signal connection, the outer wall one side of steam turbine main part is equipped with pressure detection module. The automatic protection device of extraction steam type steam turbine throws heat load, through the mutual cooperation between each module, reduced the operation amount of operating personnel under the condition of accident, can reduce the unit load fast, while reducing the exhaust pressure of medium pressure cylinder, fast boiler load and RB protection target load match, ensure the stable of boiler parameter, avoided the series operation such as manual load reduction, oil, skip mill, close the operation of reducing temperature water to be difficult to cooperate in place in the process of artificial disposal, led to the problem of accident expansion influence unit safety, can control the influence of accident in smaller range, reduced the influence to heat supply network system.

Description

Technical Field

[0001] This utility model relates to the field of extraction steam turbine technology, specifically an automatic protection device for extraction steam turbine to shed heat supply load. Background Technology

[0002] Extraction steam turbines are one of the most commonly used heating units in combined heat and power (CHP) systems. They can extract a portion of steam from the intermediate stage of the turbine for industrial or residential heating while generating electricity. The remaining steam continues to perform work before entering the condenser. Its core feature is that the electric and heat loads can be independently adjusted, making it suitable for scenarios with significant changes in heat and power demand. Extraction steam turbines extract a portion of the steam from the intermediate-pressure cylinder to the heating network heater for heat exchange, and recover the condensate to the heating network condensate tank. The condensate is then pumped back to the unit's deaerator. The amount of steam extracted for heating can be adjusted by changing the opening of the extraction regulating valve and the throttling LV valve (medium and low pressure connecting pipe butterfly valve).

[0003] When a heating network system malfunctions, such as when the heating network heaters are full of water, the heating extraction steam quick-closing valve suddenly closes, or the LV valve suddenly closes, requiring rapid load shedding, there are a series of risks, including a sudden increase in the intermediate pressure cylinder exhaust pressure, a sudden closure of the turbine inlet steam regulating valve, and a sudden increase in the boiler main steam pressure leading to overpressure. Currently, the conventional protection for such accidents is only the protection of the LV valve fully open when the intermediate pressure is high and the protection of the turbine tripping when the pressure is high. All other operations need to be performed manually by the operator, which not only involves a large amount of work, but also carries a series of risks such as the accident escalating if the timing is not right, the operation is not decisive enough, or the operation is excessive. Utility Model Content

[0004] This invention provides an automatic protection device for shedding heating load in extraction steam turbines. Through the coordinated operation of various modules, it reduces the workload of operators in case of accidents, rapidly reducing the unit load. While lowering the intermediate-pressure cylinder exhaust pressure, it quickly matches the boiler load with the RB protection target load, ensuring stable boiler parameters. This avoids the problem of difficulty in coordinating manual load reduction, oil injection, mill tripping, and shutting off the cooling water during manual handling, which could lead to the escalation of the accident and affect unit safety. It can control the impact of accidents within a smaller range, reducing the impact on the heating network system. The RB protection logic for shedding heating load automatically handles the situation in stages. When the intermediate-pressure cylinder exhaust pressure reaches 500 kPa, the LV valve begins to open at a rate of 1.5% / second. If the intermediate-pressure cylinder exhaust pressure stops rising, the LV valve remains open. For a significant number of accidents, this operation is sufficient to resolve them, avoiding the problems caused by fully opening the LV valve in traditional logic, such as a rapid increase in boiler pressure, a sudden drop in heating network heater inlet pressure, a sudden rise in heater water level, and a significant drop in heating temperature. This reduces disturbance to the system and prevents the accident from escalating.

[0005] To achieve the above objectives, this utility model provides the following technical solution: an automatic protection device for a steam turbine to shed its heating load, comprising: a turbine body, a control module, a coal mill, and a boiler. The control module is connected to the turbine body, the coal mill, and the boiler via signal connections. A pressure detection module is installed on one side of the outer wall of the turbine body, an LV valve is installed on one side of the outer wall of the turbine body, and a load regulating module is installed on the steam inlet regulating valve of the turbine body.

[0006] Furthermore, an alarm device is installed on one side of the outer wall of the control module.

[0007] Furthermore, the control module and the pressure detection module are connected by a signal.

[0008] Furthermore, the control module is connected to the LV valve via a signal connection.

[0009] Furthermore, the load regulation module and the control module are connected by a signal.

[0010] Furthermore, a desuperheating water valve module is installed on the outer wall of the boiler.

[0011] This utility model provides an automatic protection device for the shedding of heating load by an extraction steam turbine. It has the following beneficial effects:

[0012] (1) The automatic protection device for the extraction steam turbine to shed the heating load reduces the amount of operation required by the operators in case of an accident by cooperating with each module. It can quickly reduce the unit load and quickly match the boiler load with the RB protection target load while reducing the exhaust pressure of the intermediate pressure cylinder, ensuring the stability of boiler parameters. It avoids the problem that the series of operations such as manual load reduction, oil injection, mill jump and shut-off of desuperheating water are difficult to coordinate in the process of manual handling, which leads to the expansion of the accident and affects the safety of the unit. It can control the impact of the accident within a smaller range and reduce the impact on the heating network system.

[0013] (2) The automatic protection device for shedding heating load in this extraction steam turbine automatically handles the situation in stages through the heating load shedding RB protection logic. When the intermediate pressure cylinder exhaust pressure reaches 500 kPa, the LV valve starts to open at a rate of 1.5% / second. If the intermediate pressure cylinder exhaust pressure stops rising, the LV valve remains open. For a considerable number of accidents, this operation is sufficient to resolve them, avoiding the problems caused by the traditional logic of fully opening the LV valve, such as rapid increase in boiler pressure, sudden drop in heater inlet pressure, sudden rise in heater water level, and significant drop in heating temperature. This reduces disturbance to the system and prevents the accident from escalating. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the structure of this utility model;

[0015] Figure 2 This is a perspective view of the present invention.

[0016] In the diagram: 1. Steam turbine main body; 2. Control module; 3. Coal mill; 4. Boiler; 5. Pressure detection module; 6. LV valve; 7. Load regulation module; 8. Alarm device; 9. Desuperheating water valve module. Detailed Implementation

[0017] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present utility model, not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present utility model without creative effort are within the scope of protection of the present utility model.

[0018] Please see Figure 1-2 This utility model provides a technical solution: an automatic protection device for a steam turbine to shed heating load, comprising: a steam turbine body 1, a control module 2, a coal mill 3, and a boiler 4. The control module 2 is connected to the steam turbine body 1, the coal mill 3, and the boiler 4 via signal connection. A pressure detection module 5 is installed on one side of the outer wall of the steam turbine body 1. An LV valve 6 is installed on one side of the outer wall of the steam turbine body 1. A load regulating module 7 is installed on the steam inlet regulating valve of the steam turbine body 1.

[0019] In this implementation scheme: the pressure detection module 5 is installed on the intermediate pressure cylinder exhaust pipe of the turbine body 1 to detect the intermediate pressure cylinder exhaust pressure in real time. The LV valve 6 is equipped with a drive module that can receive the control command on the opening of the LV valve 6 issued by the control module 2 and drive the LV valve 6 to make corresponding opening adjustments. The load regulation module 7 can change the unit load by adjusting the opening of the steam inlet regulating valve of the turbine body 1. When the intermediate pressure cylinder exhaust pressure of the turbine body 1 reaches the RB action value, the coal mill 3 and the boiler 4 are activated in conjunction with the command of the control module 2 to ensure the safe and stable operation of the unit when the heating load is shed.

[0020] Specifically, an alarm device 8 is installed on one side of the outer wall of the control module 2.

[0021] In this embodiment: when the exhaust pressure of the intermediate pressure cylinder of the turbine body 1 is abnormal, such as reaching a dangerous value, the alarm device 8 will issue an audible and visual alarm signal according to the instruction of the control module 2, reminding the on-duty personnel to pay attention to the system operation status so that further measures can be taken in a timely manner.

[0022] Specifically, there is a signal connection between the control module 2 and the pressure detection module 5.

[0023] In this embodiment: the control module 2 receives the pressure signal from the pressure detection module 5, analyzes and processes the pressure signal transmitted from the pressure detection module 5, and issues corresponding control commands according to the preset RB protection logic based on different pressure conditions, coordinating the work of each module to realize the automatic processing of the heat load shedding situation.

[0024] Specifically, there is a signal connection between control module 2 and LV valve 6.

[0025] In this embodiment: when a small amount of heating load is shed, the LV valve 6 is quickly opened according to the instruction of the control module 2. When the exhaust pressure of the intermediate pressure cylinder of the turbine body 1 no longer rises, the current opening of the LV valve 6 is maintained to minimize the disturbance to the system. When the pressure rises further, the opening of the LV valve 6 is adjusted according to the instruction of the control module 2.

[0026] Specifically, there is a signal connection between the load regulation module 7 and the control module 2.

[0027] In this embodiment: when the exhaust pressure of the intermediate pressure cylinder of the turbine body 1 further increases to the RB action value, according to the instruction of the control module 2, the load adjustment module 7 quickly reduces the load of the unit to the main steam flow of 455t / h to prevent the unit from tripping, while ensuring the safety and stability of the parameters on the boiler side 4.

[0028] Specifically, a desuperheating water valve module 9 is installed on the outer wall of boiler 4.

[0029] In this embodiment: the desuperheating water valve module 9 is used to adjust the desuperheating water flow rate of boiler 4 and control the parameters of boiler 4. Its opening and closing are controlled by the control module 2. When RB occurs, the control module 2 controls the desuperheating water valve module 9 to close.

[0030] When in use, the RB protection logic for shedding heating load is as follows:

[0031] 1. Add a button to enable / disable the RB protection for the heating supply to the DEH screen. Enable it during heating and disable it when not heating.

[0032] 2. When the heating supply RB protection is activated, if the intermediate pressure cylinder exhaust pressure is greater than 500 kPa, the control module 2 triggers the alarm device 8 to issue a high pressure alarm signal and opens the LV valve 6 in parallel at an opening rate of 1.5% / second. If the intermediate exhaust pressure is less than 450 kPa, the control module 2 keeps the opening of the LV valve 6 unchanged to minimize disturbance to the system.

[0033] 3. When the intermediate pressure cylinder exhaust pressure is greater than 686 kPa, the control module 2 triggers the alarm device 8 to issue a high pressure alarm, quickly opens the LV valve 6, and triggers the unit RB condition. The unit quickly reduces the load at a rate of 150 MW / min. When the main steam flow rate is less than 455 t / h, the RB is reset and the load reduction stops to prevent the unit from being damaged due to excessive pressure.

[0034] 4. Mill skipping conditions: The number of mills currently in operation is greater than 2 or 3. Mill skipping sequence: skip mills in the order of E, D, C, with an interval of 5 seconds. Finally, two mills are kept in operation to ensure the stability of combustion in boiler 4.

[0035] 5. Add oil

[0036] Oil injection conditions and sequence:

[0037] Oil injection conditions for AB layers: A mill is running; Oil injection sequence for AB layers: first inject oil from angle oil guns #1 and #3, and after 10 seconds, inject oil from angle oil guns #2 and #4;

[0038] Oil injection conditions for BC layer: A mill is not running; Oil injection sequence for BC layer: first inject #1 and #3 angle oil guns, and after 10 seconds, inject #2 and #4 angle oil guns to ensure that boiler 4 can burn stably after the mill jumps.

[0039] 6. When RB occurs, close the desuperheating water valve for 4 seconds. The desuperheating water valve includes: overheating first desuperheating regulating valve, overheating second desuperheating left regulating valve, overheating second desuperheating right regulating valve, overheating third desuperheating left regulating valve, overheating second desuperheating right regulating valve, reheating A spray water regulating valve, reheating B spray water regulating valve, and reheating emergency spray water regulating valve.

[0040] 7. When the intermediate pressure cylinder exhaust pressure exceeds 882 kPa, a high pressure alarm will be issued, the intermediate exhaust pressure high protection will activate, and the turbine will trip to ensure turbine safety.

[0041] The above description is only a preferred embodiment of the present utility model, but the protection scope of the present utility model is not limited thereto. Any equivalent substitutions or changes made by those skilled in the art within the technical scope disclosed in the present utility model, based on the technical solution and the inventive concept of the present utility model, should be included within the protection scope of the present utility model.

Claims

1. An automatic protection device for shedding heating load in a steam turbine, comprising a turbine body (1), a control module (2), a coal mill (3), and a boiler (4), wherein the control module (2) is connected to the turbine body (1), the coal mill (3), and the boiler (4) via signal connections, characterized in that: A pressure detection module (5) is installed on one side of the outer wall of the turbine body (1), an LV valve (6) is installed on one side of the outer wall of the turbine body (1), and a load regulating module (7) is installed on the steam inlet regulating valve of the turbine body (1).

2. The automatic protection device for shedding heating load in an extraction steam turbine according to claim 1, characterized in that: An alarm device (8) is installed on one side of the outer wall of the control module (2).

3. The automatic protection device for shedding heating load in an extraction steam turbine according to claim 2, characterized in that: The control module (2) and the pressure detection module (5) are connected by a signal.

4. The automatic protection device for shedding heating load in an extraction steam turbine according to claim 3, characterized in that: The control module (2) is connected to the LV valve (6) via a signal connection.

5. An automatic protection device for shedding heating load in an extraction steam turbine according to claim 4, characterized in that: The load regulation module (7) is connected to the control module (2) via a signal connection.

6. An automatic protection device for shedding heating load in an extraction steam turbine according to claim 5, characterized in that: The boiler (4) is equipped with a desuperheating water valve module (9) on its outer wall.

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