Control system and method for preventing abnormal steam pressure by low-pressure cylinder zero output heat supply

Abstract

The application provides a control system for preventing steam pressure from being abnormal in low-pressure cylinder zero-power heat supply, which comprises a steam turbine medium-pressure cylinder, a steam turbine low-pressure cylinder, a pressure testing device and a hydraulic control butterfly valve. The steam turbine medium-pressure cylinder is connected with the steam turbine low-pressure cylinder through at least one steam pipeline and is used for discharging steam to the steam turbine low-pressure cylinder. The pressure testing device is used for obtaining the steam pressure at the outlet of the steam turbine medium-pressure cylinder and the steam pressure at the inlet of the steam turbine low-pressure cylinder. The hydraulic control butterfly valve is installed on the steam pipeline between the steam turbine medium-pressure cylinder and the steam turbine low-pressure cylinder and is used for regulating the opening of the hydraulic control butterfly valve until the pressure difference between the steam pressure at the outlet of the steam turbine medium-pressure cylinder and the steam pressure at the inlet of the steam turbine low-pressure cylinder is less than a preset deviation. Therefore, the automatic control level of the steam pressure in the low-pressure cylinder zero-power heat supply is effectively improved by regulating the steam pressure at the outlet of the steam turbine medium-pressure cylinder and the steam pressure at the inlet of the steam turbine low-pressure cylinder, and the safe operation of the low-pressure cylinder zero-power heat supply is ensured.

Description

Technical Field

[0001] This application relates to the field of heating unit technology, specifically to a control system and method for preventing abnormal steam pressure in low-pressure cylinder zero-output heating. Background Technology

[0002] Currently, the low-pressure cylinder zero-output technology is relatively mature and has been successfully applied to multiple units. However, due to load changes, improper operation by operators, and unreasonable control system design, units modified for low-pressure cylinder zero-output may experience issues such as increased exhaust pressure in the intermediate-pressure cylinder or decreased inlet pressure in the low-pressure cylinder during operation. In severe cases, this can even cause the unit to exit low-pressure cylinder zero-output operation, leading to a series of negative consequences. In related technologies, the exhaust pressure of the intermediate-pressure cylinder and the inlet pressure of the low-pressure cylinder are generally adjusted manually based on experience. However, this adjustment is not timely or accurate. Therefore, there is an urgent need for a more reliable control system for low-pressure cylinder zero-output heating to prevent abnormal steam pressure. Summary of the Invention

[0003] One embodiment of this application proposes a control system for preventing abnormal steam pressure during zero-output heating of a low-pressure cylinder. The system includes a turbine intermediate-pressure cylinder, a turbine low-pressure cylinder, a pressure testing device, and a hydraulically controlled butterfly valve, wherein:

[0004] The intermediate pressure cylinder of the steam turbine is connected to the low pressure cylinder of the steam turbine through at least one steam pipe, and is used to discharge steam to the low pressure cylinder of the steam turbine.

[0005] The pressure testing device is installed at the outlet of the intermediate-pressure cylinder of the steam turbine and the inlet of the low-pressure cylinder of the steam turbine, respectively, to obtain the steam pressure at the outlet of the intermediate-pressure cylinder of the steam turbine and the steam pressure at the inlet of the low-pressure cylinder of the steam turbine.

[0006] The hydraulic control butterfly valve is installed on the steam pipeline between the intermediate-pressure cylinder and the low-pressure cylinder of the steam turbine, and is used to regulate the opening of the hydraulic control butterfly valve until the pressure difference between the steam pressure at the outlet of the intermediate-pressure cylinder and the steam pressure at the inlet of the low-pressure cylinder is less than a preset deviation.

[0007] In one embodiment of this application, the system further includes an electrically controlled regulating valve for low-pressure cylinder cooling steam, wherein:

[0008] The low-pressure cylinder cooling steam electric regulating valve is installed on the exhaust pipe between the intermediate-pressure cylinder and the low-pressure cylinder of the steam turbine, and is used to discharge steam to the low-pressure cylinder and regulate the pressure of the steam in the exhaust pipe.

[0009] In one embodiment of this application, the system further includes a pneumatic check valve for the heating steam extraction pipeline, wherein:

[0010] The pneumatic check valve for the heating extraction pipeline is installed on the heating extraction pipeline between the intermediate pressure cylinder and the low pressure cylinder of the turbine to prevent steam backflow in the heating extraction pipeline.

[0011] In one embodiment of this application, the system further includes a hydraulically controlled butterfly valve for the heating network extraction steam pipeline, wherein:

[0012] The hydraulic control butterfly valve of the heating network extraction pipeline is also installed on the heating extraction pipeline to regulate the pressure of steam in the heating extraction pipeline.

[0013] In one embodiment of this application, when the low-pressure cylinder of the steam turbine is supplying heat, the opening degree of the hydraulic control butterfly valve and the opening degree of the low-pressure cylinder cooling steam electric regulating valve are continuously adjusted, the pneumatic check valve of the heating extraction steam pipeline on the heating extraction steam pipeline is opened, and the opening degree of the hydraulic control butterfly valve of the heating network extraction steam pipeline on the heating network extraction steam pipeline is adjusted until the pressure difference is less than the preset deviation.

[0014] In one embodiment of this application, when the intermediate-pressure cylinder of the steam turbine is connected to the low-pressure cylinder of the steam turbine through two steam pipes, the hydraulic control butterfly valve is installed on both steam pipes.

[0015] In one embodiment of this application, the upper limit of the opening degree of the hydraulic butterfly valve is determined by the equipment parameters of the steam turbine.

[0016] In one embodiment of this application, when the pressure testing device consists of multiple pressure sensors, the average measurement value of the multiple pressure sensors installed at the outlet of the intermediate pressure cylinder of the steam turbine is taken as the steam pressure at the outlet of the intermediate pressure cylinder of the steam turbine, and the average measurement value of the multiple pressure sensors installed at the inlet of the low pressure cylinder of the steam turbine is taken as the steam pressure at the inlet of the low pressure cylinder of the steam turbine.

[0017] This application proposes a control system for preventing abnormal steam pressure during zero-output heating of a low-pressure cylinder. The system includes a turbine intermediate-pressure cylinder, a turbine low-pressure cylinder, a pressure testing device, and a hydraulically controlled butterfly valve. The turbine intermediate-pressure cylinder is connected to the turbine low-pressure cylinder via at least one steam pipeline for discharging steam into the turbine low-pressure cylinder. The pressure testing device is used to obtain the steam pressure at the outlet of the turbine intermediate-pressure cylinder and the steam pressure at the inlet of the turbine low-pressure cylinder. The hydraulically controlled butterfly valve is installed on the steam pipeline between the turbine intermediate-pressure cylinder and the turbine low-pressure cylinder and is used to regulate the opening of the hydraulically controlled butterfly valve until the pressure difference between the steam pressure at the outlet of the turbine intermediate-pressure cylinder and the steam pressure at the inlet of the turbine low-pressure cylinder is less than a preset deviation. Thus, by regulating the steam pressure at the outlet of the turbine intermediate-pressure cylinder and the steam pressure at the inlet of the turbine low-pressure cylinder, the automatic control level of steam pressure during zero-output heating of the low-pressure cylinder is effectively improved, ensuring the safe operation of zero-output heating of the low-pressure cylinder.

[0018] Another embodiment of this application proposes a control method for preventing abnormal steam pressure during zero-output heating of a low-pressure cylinder, the method comprising:

[0019] Obtain the steam pressure at the outlet of the intermediate-pressure cylinder of the steam turbine and the steam pressure at the inlet of the low-pressure cylinder of the steam turbine;

[0020] Based on the pressure difference between the steam pressure at the outlet of the intermediate-pressure cylinder of the steam turbine and the steam pressure at the inlet of the low-pressure cylinder of the steam turbine, the discharged steam is regulated until the pressure difference is less than a preset deviation.

[0021] This application proposes a control method for preventing abnormal steam pressure during zero-output heating of the low-pressure cylinder. The method involves acquiring the steam pressure at the outlet of the intermediate-pressure cylinder of the turbine and the steam pressure at the inlet of the low-pressure cylinder. Based on the pressure difference between these two pressures, the discharged steam is regulated until the pressure difference is less than a preset deviation. Therefore, by regulating the steam pressure at the outlet of the intermediate-pressure cylinder and the inlet of the low-pressure cylinder, the automatic control level of steam pressure during zero-output heating of the low-pressure cylinder is effectively improved, ensuring the safe operation of zero-output heating of the low-pressure cylinder.

[0022] Other effects of the above-mentioned alternative methods will be described below in conjunction with specific embodiments. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the structure of a control system for preventing abnormal steam pressure in a low-pressure cylinder zero-output heating according to an embodiment of this application.

[0024] Figure 2 This is a schematic diagram of a control method for a hydraulically controlled butterfly valve according to an embodiment of this application;

[0025] Figure 3 This is a schematic flowchart of a control method for preventing abnormal steam pressure in a low-pressure cylinder with zero output heating according to an embodiment of this application. Detailed Implementation

[0026] The embodiments of this application are described in detail below. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application.

[0027] The following describes a control system for preventing abnormal steam pressure in a low-pressure cylinder with zero output heating, according to an embodiment of this application, with reference to the accompanying drawings.

[0028] Figure 1 This is a schematic diagram of the structure of a control system for preventing abnormal steam pressure by providing zero-output heating to a low-pressure cylinder according to an embodiment of this application.

[0029] like Figure 1As shown, the control system 100 for preventing abnormal steam pressure by zero-output heating of the low-pressure cylinder includes a turbine intermediate-pressure cylinder 101, a turbine low-pressure cylinder 102, a pressure testing device 103, and a hydraulic butterfly valve 104, wherein:

[0030] Optionally, such as Figure 1 As shown, the intermediate pressure cylinder 101 of the steam turbine is connected to the low pressure cylinder 102 of the steam turbine through at least one steam pipe, and is used to discharge steam to the low pressure cylinder 102 of the steam turbine.

[0031] In some embodiments, such as Figure 1 As shown, when the intermediate pressure cylinder 101 of the steam turbine is connected to the low pressure cylinder 102 of the steam turbine through two steam pipes, a hydraulic butterfly valve 104 is installed on both steam pipes.

[0032] The number of steam pipes between the intermediate-pressure cylinder 101 and the low-pressure cylinder 102 of the steam turbine is determined by the application requirements of the steam turbine, and this embodiment does not impose specific limitations on this.

[0033] Optionally, such as Figure 1 As shown, the pressure testing device 103 is installed at the outlet of the intermediate pressure cylinder 101 and the inlet of the low pressure cylinder 102 of the steam turbine, respectively, to obtain the steam pressure at the outlet of the intermediate pressure cylinder and the steam pressure at the inlet of the low pressure cylinder.

[0034] In some embodiments, when the pressure testing device 103 consists of multiple pressure sensors, the average measurement value of the multiple pressure sensors installed at the outlet of the intermediate pressure cylinder 101 of the steam turbine is taken as the steam pressure at the outlet of the intermediate pressure cylinder of the steam turbine, and the average measurement value of the multiple pressure sensors installed at the inlet of the low pressure cylinder 102 of the steam turbine is taken as the steam pressure at the inlet of the low pressure cylinder of the steam turbine.

[0035] The number of pressure sensors can be up to three, but is not limited to this.

[0036] Optionally, such as Figure 1 As shown, the hydraulic control butterfly valve 104 is installed on the steam pipeline between the intermediate pressure cylinder 101 and the low pressure cylinder 102 of the steam turbine, and is used to regulate the opening of the hydraulic control butterfly valve 104 until the pressure difference between the steam pressure at the outlet of the intermediate pressure cylinder and the steam pressure at the inlet of the low pressure cylinder is less than the preset deviation.

[0037] In some embodiments, the upper limit of the opening degree of the hydraulic butterfly valve 104 is determined by the equipment parameters of the steam turbine.

[0038] Understandably, in order to ensure the stable operation of the turbine unit, the opening degree of the hydraulic butterfly valve 104 cannot remain in the range of 0 to a certain value (upper limit of opening degree) for a long time. For example, the intermediate pressure cylinder 101 of the turbine is connected to the low pressure cylinder 102 of the turbine through two steam pipes, and hydraulic butterfly valves 104 are installed on the two steam pipes respectively, and the pressure testing device 103 consists of three sensors.

[0039] Specifically, such as Figure 2 As shown, Figure 2 Three implementation methods for adjusting the opening degree of the hydraulic butterfly valve 104, such as Figure 2 As shown, in the first embodiment, when the opening degree of both hydraulic butterfly valves 104 is less than 25%, the average value of three sensors (first pressure sensor, second pressure sensor, and third pressure sensor) at the outlet of the intermediate pressure cylinder 101 of the steam turbine is selected every 3 seconds, and the exhaust pressure value of the intermediate pressure cylinder when the hydraulic butterfly valve 104 is fully open is selected. When the average value of the three sensors (steam pressure value at the outlet of the intermediate pressure cylinder of the steam turbine) is greater than 1.05 times the exhaust pressure of the intermediate pressure cylinder when the valve is fully open (0.548MPa), the opening degree of the two hydraulic butterfly valves 104 is quickly adjusted to 25%.

[0040] In the second embodiment, when the opening degree of both hydraulic butterfly valves 104 is less than 25%, the average value of three sensors at the outlet of the intermediate pressure cylinder 101 of the steam turbine is selected every 3 seconds, and the exhaust pressure value of the intermediate pressure cylinder when the hydraulic butterfly valve 104 is fully open is selected. When the average value of the three sensors (the steam pressure value at the outlet of the intermediate pressure cylinder of the steam turbine) is greater than 1.05 times the exhaust pressure of the intermediate pressure cylinder when the valve is fully open (0.548MPa), the opening degree of the two hydraulic butterfly valves 104 is continuously adjusted (by 1% every 30 seconds) until the steam pressure value at the outlet of the intermediate pressure cylinder of the steam turbine is lower than 1.0 times the exhaust pressure of the intermediate pressure cylinder when the valve is fully open (0.548MPa).

[0041] In the third embodiment, when the opening degree of both hydraulic control butterfly valves 104 is greater than 25%, the average value of three sensors (fourth pressure sensor, fifth pressure sensor, and sixth pressure sensor) at the outlet of the low-pressure cylinder 102 of the steam turbine is selected every 3 seconds, and a preset pressure value is selected. When the average value of the three sensors (the steam pressure value at the inlet of the low-pressure cylinder of the steam turbine) is lower than the preset pressure value (0.1000MPa), the opening degree of the two hydraulic control butterfly valves 104 is continuously adjusted (by 1% every 30 seconds) until the steam pressure value at the inlet of the low-pressure cylinder of the steam turbine is higher than the preset pressure value (0.1000MPa).

[0042] in, Figure 2 In this context, H / / indicates greater than, / / L indicates less than, and AND indicates a gate.

[0043] Optionally, such as Figure 1As shown, the system also includes a low-pressure cylinder cooling steam electric regulating valve 105, wherein:

[0044] The low-pressure cylinder cooling steam electric regulating valve 105 is installed on the exhaust pipe between the intermediate-pressure cylinder 101 and the low-pressure cylinder 102 of the steam turbine. It is used to discharge steam to the low-pressure cylinder and regulate the pressure of the steam in the exhaust pipe.

[0045] Optionally, such as Figure 1 As shown, the system also includes a pneumatic check valve 106 for the heating steam extraction pipeline, wherein:

[0046] The pneumatic check valve 106 for the heating extraction pipeline is installed on the heating extraction pipeline between the intermediate pressure cylinder 101 and the low pressure cylinder 102 of the steam turbine to prevent steam backflow in the heating extraction pipeline.

[0047] Optionally, such as Figure 1 As shown, the system also includes a hydraulically controlled butterfly valve 107 for the heating network extraction steam pipeline, wherein:

[0048] The hydraulic control butterfly valve 107 of the heating network extraction steam pipeline is also installed on the heating extraction steam pipeline to regulate the pressure of steam in the heating extraction steam pipeline.

[0049] In summary, the control process for preventing abnormal steam pressure during zero-output heating of the low-pressure cylinder can be as follows: the exhaust steam from the intermediate-pressure cylinder 101 of the steam turbine is discharged to the low-pressure cylinder 102 of the steam turbine through the steam pipeline equipped with the hydraulic control butterfly valve 104. When the low-pressure cylinder 102 of the steam turbine is not in zero-output heating mode, the opening degree of the hydraulic control butterfly valve 104 is limited to 100%, and the electric regulating valve 105 for cooling steam of the low-pressure cylinder, the pneumatic check valve 106 for heating extraction steam pipeline, and the hydraulic control butterfly valve 107 for heating network extraction steam pipeline are all in the closed state.

[0050] When the low-pressure cylinder 102 of the steam turbine is supplying heat, continuously adjust the opening of the hydraulic control butterfly valve 104 and the opening of the low-pressure cylinder cooling steam electric regulating valve 105, open the pneumatic check valve 106 on the heating extraction steam pipeline, and adjust the opening of the hydraulic control butterfly valve 107 on the heating network extraction steam pipeline until the pressure difference is less than the preset deviation.

[0051] Specifically, after the low-pressure cylinder is put into heating, the 100% opening limit of the hydraulic control butterfly valve 104 is released, and after the pipe warm-up operation is performed, the opening of the hydraulic control butterfly valve 104 is continuously adjusted, the pneumatic check valve 106 of the heating extraction steam pipeline is opened, and the opening of the hydraulic control butterfly valve 107 of the heating network extraction steam pipeline is adjusted to start heating. At the same time, in order to ensure the minimum steam flow rate entering the low-pressure cylinder 102 of the steam turbine, the opening of the low-pressure cylinder cooling steam electric regulating valve 105 can be opened to 20%.

[0052] This application proposes a control system for preventing abnormal steam pressure during zero-output heating of a low-pressure cylinder. The system includes a turbine intermediate-pressure cylinder, a turbine low-pressure cylinder, a pressure testing device, and a hydraulically controlled butterfly valve. The turbine intermediate-pressure cylinder is connected to the turbine low-pressure cylinder via at least one steam pipeline for discharging steam into the turbine low-pressure cylinder. The pressure testing device is used to obtain the steam pressure at the outlet of the turbine intermediate-pressure cylinder and the steam pressure at the inlet of the turbine low-pressure cylinder. The hydraulically controlled butterfly valve is installed on the steam pipeline between the turbine intermediate-pressure cylinder and the turbine low-pressure cylinder and is used to regulate the opening of the hydraulically controlled butterfly valve until the pressure difference between the steam pressure at the outlet of the turbine intermediate-pressure cylinder and the steam pressure at the inlet of the turbine low-pressure cylinder is less than a preset deviation. Thus, by regulating the steam pressure at the outlet of the turbine intermediate-pressure cylinder and the steam pressure at the inlet of the turbine low-pressure cylinder, the automatic control level of steam pressure during zero-output heating of the low-pressure cylinder is effectively improved, ensuring the safe operation of zero-output heating of the low-pressure cylinder.

[0053] To provide a clearer understanding of this application, a flowchart illustrating a control method for preventing abnormal steam pressure in a low-pressure cylinder with zero output heating is also provided, as shown below. Figure 3 As shown.

[0054] like Figure 3 As shown, the control method for preventing abnormal steam pressure in the low-pressure cylinder zero-output heating system includes:

[0055] Step 301: Obtain the steam pressure at the outlet of the intermediate-pressure cylinder of the steam turbine and the steam pressure at the inlet of the low-pressure cylinder of the steam turbine.

[0056] The steam pressure at the outlet of the intermediate-pressure cylinder and the steam pressure at the inlet of the low-pressure cylinder can be measured by a single sensor or by the average of measurements from multiple sensors. This embodiment does not specifically limit the measurement values.

[0057] Step 302: Based on the pressure difference between the steam pressure at the outlet of the intermediate-pressure cylinder of the steam turbine and the steam pressure at the inlet of the low-pressure cylinder of the steam turbine, the discharged steam is regulated until the pressure difference is less than the preset deviation.

[0058] The preset deviation can be set by relevant technical personnel or by combining historical data of steam pressure when the low-pressure cylinder is heating at zero output. This embodiment does not specifically limit this.

[0059] This application proposes a control method for preventing abnormal steam pressure during zero-output heating of the low-pressure cylinder. The method involves acquiring the steam pressure at the outlet of the intermediate-pressure cylinder of the turbine and the steam pressure at the inlet of the low-pressure cylinder. Based on the pressure difference between these two pressures, the discharged steam is regulated until the pressure difference is less than a preset deviation. Therefore, by regulating the steam pressure at the outlet of the intermediate-pressure cylinder and the inlet of the low-pressure cylinder, the automatic control level of steam pressure during zero-output heating of the low-pressure cylinder is effectively improved, ensuring the safe operation of zero-output heating of the low-pressure cylinder.

[0060] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0061] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0062] Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of this application.

Claims

1. A control system for preventing abnormal steam pressure in a low-pressure cylinder with zero output heating, characterized in that, The system includes a steam turbine intermediate-pressure cylinder, a steam turbine low-pressure cylinder, a pressure testing device, and a hydraulically controlled butterfly valve, wherein: The intermediate pressure cylinder of the steam turbine is connected to the low pressure cylinder of the steam turbine through at least one steam pipe, and is used to discharge steam to the low pressure cylinder of the steam turbine. The pressure testing device is installed at the outlet of the intermediate-pressure cylinder of the steam turbine and the inlet of the low-pressure cylinder of the steam turbine, respectively, to obtain the steam pressure at the outlet of the intermediate-pressure cylinder of the steam turbine and the steam pressure at the inlet of the low-pressure cylinder of the steam turbine. The hydraulic control butterfly valve is installed on the steam pipeline between the intermediate pressure cylinder and the low pressure cylinder of the steam turbine, and is used to regulate the opening of the hydraulic control butterfly valve until the pressure difference between the steam pressure at the outlet of the intermediate pressure cylinder and the steam pressure at the inlet of the low pressure cylinder is less than a preset deviation. When the low-pressure cylinder of the steam turbine is supplying heat, continuously adjust the opening of the hydraulic butterfly valve and the opening of the electric regulating valve for cooling steam of the low-pressure cylinder, open the pneumatic check valve on the heating extraction steam pipeline, and adjust the opening of the hydraulic butterfly valve on the heating network extraction steam pipeline until the pressure difference is less than the preset deviation. When the intermediate-pressure cylinder of the steam turbine is connected to the low-pressure cylinder of the steam turbine through two steam pipes, the hydraulic control butterfly valve is installed on both steam pipes. The upper limit of the opening degree of the hydraulic butterfly valve is determined by the equipment parameters of the steam turbine; When the pressure testing device consists of multiple pressure sensors, the average measurement value of the multiple pressure sensors installed at the outlet of the intermediate pressure cylinder of the steam turbine is taken as the steam pressure at the outlet of the intermediate pressure cylinder of the steam turbine, and the average measurement value of the multiple pressure sensors installed at the inlet of the low pressure cylinder of the steam turbine is taken as the steam pressure at the inlet of the low pressure cylinder of the steam turbine. The system also includes an electrically controlled regulating valve for low-pressure cylinder cooling steam, wherein: The low-pressure cylinder cooling steam electric regulating valve is installed on the exhaust pipe between the intermediate-pressure cylinder and the low-pressure cylinder of the steam turbine, and is used to discharge steam to the low-pressure cylinder and regulate the pressure of the steam in the exhaust pipe. The system also includes a pneumatic check valve for the heating steam extraction pipeline, wherein: The pneumatic check valve for the heating extraction pipeline is installed on the heating extraction pipeline between the intermediate pressure cylinder and the low pressure cylinder of the steam turbine to prevent steam backflow in the heating extraction pipeline. The system also includes a hydraulically controlled butterfly valve for the heating network extraction steam pipeline, wherein: The hydraulic control butterfly valve of the heating network extraction pipeline is also installed on the heating extraction pipeline to regulate the pressure of steam in the heating extraction pipeline.

2. A control method for preventing abnormal steam pressure during zero-output heating of a low-pressure cylinder, characterized in that, The method is applied to the system as described in claim 1, and the method includes: Obtain the steam pressure at the outlet of the intermediate-pressure cylinder of the steam turbine and the steam pressure at the inlet of the low-pressure cylinder of the steam turbine; Based on the pressure difference between the steam pressure at the outlet of the intermediate-pressure cylinder of the steam turbine and the steam pressure at the inlet of the low-pressure cylinder of the steam turbine, the discharged steam is regulated until the pressure difference is less than a preset deviation.

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