A low-voltage electric regulating system for high-speed rotating units

Abstract

The present application relates to a kind of low pressure electric regulating system for high speed unit, including main steam valve control oil circuit, regulating valve control oil circuit and shutdown control oil circuit, the input end of main steam valve control oil circuit and regulating valve control oil circuit is connected with the same pressure oil source, the input end of shutdown control oil circuit is connected with main steam valve control oil circuit, the output end of main steam valve control oil circuit, regulating valve control oil circuit and shutdown control oil circuit is all communicated with oil return circuit;Regulating valve control oil circuit converts pressure oil into adjusting oil and pulse oil, and the opening of admission regulating valve is adjusted by adjusting oil and pulse oil together;Main steam valve control oil circuit converts pressure oil into the safety oil of multiple outputs, one way safety oil controls main steam valve opening and closing, another way safety oil controls pulse oil release to close admission regulating valve;Shutdown control oil circuit is discharged to oil return circuit by pressure oil and safety oil, to realize shutdown.The present application only uses one pressure oil source, equipment cost is low, degree of automation is high, reliability is high, and system compatibility is good simultaneously.

Description

Technical Field

[0001] This invention relates to the field of steam turbine control technology, and more specifically to a low-voltage electronic control system for high-speed units. Background Technology

[0002] A steam turbine is a prime mover that directly converts the thermal energy of steam into rotational mechanical energy. It works by causing steam to expand in nozzles, reducing pressure and increasing velocity, thus converting the steam's thermal energy into kinetic energy. This kinetic energy is then converted into the mechanical energy of the rotating impeller shaft, driving a generator to produce electricity. Currently, high-speed steam turbines are widely used in self-owned power plants or small and medium-sized power plants in industries such as cement, chemical, petroleum, metallurgy, coking, biomass energy, and waste incineration. They effectively utilize low-parameter energy sources such as waste steam from production processes, increasing power generation and improving energy efficiency.

[0003] Currently, conventional high-speed steam turbines lack a dedicated high-speed shaft head pump, requiring a separate hydraulic actuator for the main steam valve control, resulting in multiple independent control oil circuits. Furthermore, conventional high-speed units demand high control oil pressure (approximately 14 MPa), while their lubrication system operates at lower pressure (around 1 MPa). Using separate oil sources for control and lubrication makes shared oil supply difficult, leading to high equipment costs. To gain a competitive edge, the regulation system of high-speed steam turbines needs to be redesigned to improve compatibility with the turbine, reduce costs, and maintain sufficient control accuracy. Summary of the Invention

[0004] Based on the above description, the present invention provides a low-voltage electric control system for high-speed units, which mainly solves the problem that the control system equipment cost is high when the steam turbine is controlled by multiple oil sources and multiple control oil circuits.

[0005] The technical solution of the present invention to solve the above-mentioned technical problems is as follows:

[0006] A low-voltage electrical control system for high-speed generator units includes a main steam valve control oil circuit, a regulating valve control oil circuit, and a shutdown control oil circuit. The input ends of the main steam valve control oil circuit and the regulating valve control oil circuit are connected to the same pressure oil source. The input end of the shutdown control oil circuit is connected to the main steam valve control oil circuit. The output ends of the main steam valve control oil circuit, the regulating valve control oil circuit, and the shutdown control oil circuit are all connected to the return oil circuit.

[0007] The regulating valve control oil circuit is used to convert pressure oil into regulating oil and pulse oil, and the opening of the steam inlet regulating valve is adjusted by the regulating oil and pulse oil together.

[0008] The main steam valve control oil circuit is used to convert pressure oil into multi-output safety oil. One safety oil is used to control the opening and closing state of the main steam valve, and another safety oil is released to the return oil circuit through the control pulse oil to close the steam inlet regulating valve.

[0009] The shutdown control oil circuit is connected to the pressure oil and safety oil lines, and is used to achieve shutdown by releasing the pressure oil and safety oil to the return oil circuit.

[0010] Compared with the prior art, the technical solution of this application has the following beneficial technical effects:

[0011] This invention provides a low-pressure electronic control system for high-speed turbine units. It requires only one pressure oil source to control the main steam valve and inlet regulating valve of a high-speed steam turbine, as well as to achieve shutdown control, thus reducing equipment costs. Furthermore, the system uses low-pressure oil for control, reducing the requirements for oil quality and providing higher oil resistance, thereby lowering the overall production, testing, and maintenance costs. This system is suitable for high-speed steam turbines and features low cost, high automation, and high reliability. It can also be easily modified for use with other types of steam turbines, demonstrating good compatibility.

[0012] Based on the above technical solution, the present invention can be further improved as follows.

[0013] Furthermore, the regulating valve control oil circuit includes an oil filter, a throttle valve actuator, a servo valve, and an unloading valve. The oil filter is used to filter the pressure oil into regulating oil that meets the oil quality accuracy requirements. The servo valve is used to convert the regulating oil into pulse oil. The throttle valve actuator is used to control the opening degree of the steam inlet regulating valve according to the regulating oil and the pulse oil. The unloading valve is used to release the pulse oil to close the steam inlet regulating valve.

[0014] The beneficial effects of adopting the above technical solution are as follows: The oil filter filters the pressure oil entering the control oil circuit of the regulating valve to remove impurities and protect downstream hydraulic components. The regulating oil provides power for the operation of the throttle valve actuator. The servo valve converts the regulating oil into pulse oil according to the received servo signal. The pulse oil controls the position of the slide valve in the throttle valve actuator, thereby controlling the position of the piston in the actuator. The change in the position of the actuator piston corresponds to the change in the opening of the steam inlet regulating valve, such as an increase or decrease in the steam inlet flow. During normal operation, the unloading valve is in the closed state. When a shutdown is required, the unloading valve opens to relieve the pressure of the pulse oil, causing the throttle valve actuator to control the steam inlet regulating valve to close.

[0015] Furthermore, the pulse oil output end of the servo valve and the pulse oil input end of the throttle valve actuator are connected to the regulating oil pipeline through a throttle branch, and a throttle orifice plate is connected in series in the throttle branch.

[0016] The beneficial effects of adopting the above technical solution are as follows: By connecting the regulating oil in the regulating oil pipeline to the pulse oil input terminal of the throttle actuator through the throttle branch, the throttle branch provides a base oil pressure for the slide valve control of the throttle actuator. The pressure of the pulse oil is then superimposed on the base oil pressure, achieving more precise control of the throttle actuator. The size of the throttle orifice plate can be set according to the required base oil pressure.

[0017] Furthermore, a pulse oil pressure regulating branch is provided between the pulse oil output end of the servo valve and the return oil circuit. The pressure regulating branch is equipped with a throttle valve, which is used to control the discharge of pulse oil when the servo valve is adjusted to zero position.

[0018] The beneficial effects of adopting the above technical solution are as follows: The pulse oil pressure regulating branch is mainly used to control the oil pressure of the pulse oil, such as adjusting the zero position of the servo valve, that is, the oil pressure when the servo valve is at the zero position. The flow rate of the throttle valve can be adjusted by controlling the throttle cross-section or throttle length of the throttle valve, and the oil pressure of the pulse oil pressure regulating branch can be controlled by adjusting the flow rate of the throttle valve.

[0019] Furthermore, the servo valve's pulse oil output terminal is also equipped with a pulse oil measuring point to monitor the pulse oil pressure.

[0020] The beneficial effects of adopting the above technical solution are as follows: the oil pressure of the pulse oil can be monitored in real time through the pulse oil measuring point, so as to achieve precise control of the throttle motor when the throttle is not turned.

[0021] Furthermore, the main steam valve control oil circuit includes a gate solenoid valve and an automatic shut-off device. The gate solenoid valve is used to convert pressure oil into safety oil and output it to the automatic shut-off device and the unloading valve through pipelines. The automatic shut-off device is used to open the main steam valve according to the pressure of the safety oil. The control end of the unloading valve is connected to the safety oil pipeline. The two ends of the unloading valve channel are connected to the pulse oil pipeline and the return oil pipeline, respectively. It is used to close the channel between the pulse oil pipeline and the return oil pipeline when the pressure of the safety oil is high, and to open the channel between the pulse oil pipeline and the return oil pipeline when the pressure of the safety oil decreases.

[0022] The beneficial effects of adopting the above technical solution are as follows: The solenoid valve has multiple output terminals to achieve multi-channel output of safety oil. The automatic shut-off device uses safety oil to drive its internal piston rod to move, thereby controlling the opening and closing of the main steam valve. When the automatic shut-off device is not working, it is in a normally closed state to close the main steam valve. When a certain pressure of safety oil is applied, it can open the main steam valve. The unloading valve is controlled by the hydraulic pressure of safety oil to open and close, mainly used to control the release of pulse oil. During normal operation, under the control of safety oil, the unloading valve is closed. At this time, the pulse oil enters the throttle valve actuator to control its operation, thereby adjusting the opening of the steam inlet regulating valve. When shutdown is required, the safety oil is released into the return oil circuit. At this time, the unloading valve opens, releasing the pulse oil into the return oil circuit, thereby returning the throttle valve actuator to the closed position to close the steam inlet regulating valve. The setting of the unloading valve allows the main steam valve and the regulating valve to close simultaneously when the safety oil is released.

[0023] Furthermore, a tightness test solenoid valve is also provided in the safety oil line between the output end of the solenoid valve and the input end of the automatic shut-off device. The tightness test solenoid valve has two sets of switching channels with opposite switching states. The first set of switching channels is connected to the safety oil line between the output end of the solenoid valve and the input end of the automatic shut-off device, and the second set of switching channels is connected to the safety oil line at the input end of the automatic shut-off device and the return oil line. During normal operation, the first set of switching channels of the tightness test solenoid valve is turned on and the second set of switching channels is turned off. When a tightness test is performed, the second set of switching channels of the tightness test solenoid valve is turned on and the first set of switching channels is turned off.

[0024] The beneficial effects of adopting the above technical solution are as follows: when the tightness test solenoid valve receives the test control signal, the tightness test of the main steam valve of the low-pressure electric control system can be realized by switching the on and off states of the two sets of switching channels of the tightness test solenoid valve. The operation is simple and easy to implement.

[0025] Furthermore, the shutdown control oil circuit includes an AST solenoid valve assembly, which has at least two independent switching channels. The first set of switching channels is connected to the pressure oil line and the return oil line, and the second set of switching channels is connected to the safety oil line and the return oil line, for releasing pressure oil and / or safety oil according to the shutdown signal.

[0026] The beneficial effects of adopting the above technical solution are as follows: During normal system operation, both the first and second sets of switching channels of the AST solenoid valve assembly are normally closed. When the AST solenoid valve assembly receives a shutdown signal, it opens the first and second sets of switching channels according to the shutdown signal, releasing the pressure oil and safety oil to the return oil circuit. At this time, due to the rapid decrease in safety oil pressure, it is insufficient to drive the automatic shut-off device to open, thus closing the main steam valve. Furthermore, due to the decrease in safety oil pressure, the channel connecting the pulse oil and return oil in the unloading valve changes from closed to open, thereby releasing the pulse oil in the pulse oil pipeline, causing the steam inlet regulating valve to close. Since the first switching channel releases the pressure oil to the return oil circuit, no new pressure oil enters the regulating valve control oil circuit and the main steam valve control oil circuit, thus achieving the overall shutdown of the turbine unit.

[0027] Furthermore, the AST solenoid valve assembly includes multiple AST solenoid valves arranged in parallel. Each AST solenoid valve is a four-position two-way valve, and each AST solenoid valve has two sets of independent switching channels.

[0028] The beneficial effects of adopting the above technical solution are as follows: setting up multiple AST solenoid valves in parallel, with each AST solenoid valve being redundant with the others, improves the reliability of system operation.

[0029] Furthermore, the shutdown control oil circuit also includes a manual gate valve, which has at least one set of switching channels connected to the safety oil line and the return oil line, for releasing safety oil by manually operating the actuator.

[0030] The benefits of adopting the above technical solution are as follows: in emergency situations, the system can be manually shut down, which enriches the system's operation methods and enhances the system's reliability and security. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the module composition of a low-voltage electronic control system for high-speed generator units provided in an embodiment of the present invention;

[0032] Figure 2 The oil circuit schematic diagram of the low-voltage electronic control system for high-speed units provided by the present invention.

[0033] The attached diagram lists the components represented by each number as follows:

[0034] 1. Unloading valve, 2. Steam inlet regulating valve, 3. Thickness control hydraulic actuator, 4. Regulating oil line, 5. Pulse oil line, 6. Servo valve, 7. Throttle valve, 8. Oil filter, 9 / 13. Pressure oil line, 10. AST solenoid valve assembly, 11. Gate solenoid valve, 12. Manual gate valve, 14. Safety oil line, 15. Tightness test solenoid valve, 16. Automatic shut-off device, 17. Throttling orifice plate. Detailed Implementation

[0035] To facilitate understanding of this application, a more complete description will be provided below with reference to the accompanying drawings, which illustrate embodiments of the present application. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that the disclosure of this application will be thorough and complete.

[0036] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

[0037] It is understood that spatial relation terms such as "below," "under," "below," "below," "above," "over," etc., can be used here to describe the relationship between one element or feature shown in the figure and other elements or features. It should be understood that, in addition to the orientation shown in the figure, spatial relation terms also include different orientations of the device in use and operation. For example, if the device in the figure is flipped, the element or feature described as "below" or "under" or "below" of other elements or features will be oriented "over" of other elements or features. Therefore, the exemplary terms "below" and "under" can include both upper and lower orientations. Furthermore, the device may also include other orientations (e.g., rotated 90 degrees or other orientations), and the spatial descriptive terms used herein will be interpreted accordingly.

[0038] It should be noted that when one element is considered to be "connected" to another element, it can be directly connected to the other element or connected to the other element through an intermediary element. In the following embodiments, "connection" should be understood as "electrical connection," "communication connection," etc., if the connected circuits, modules, units, etc., have the transmission of electrical signals or data between them.

[0039] When used herein, the singular forms of “a,” “an,” and “the” may also include the plural forms unless the context clearly indicates otherwise. It should also be understood that the terms “comprising,” “including,” or “having,” etc., specify the presence of the stated feature, whole, step, operation, component, part, or combination thereof, but do not preclude the possibility of the presence or addition of one or more other features, wholes, steps, operations, components, parts, or combinations thereof.

[0040] Combination Figure 1 and Figure 2 As shown, this embodiment of the invention provides a low-pressure electric control system for high-speed generator units, including a main steam valve control oil circuit, a regulating valve control oil circuit, and a shutdown control oil circuit. The input ends of the main steam valve control oil circuit and the regulating valve control oil circuit are connected to the same pressure oil source, and the input end of the shutdown control oil circuit is connected to the main steam valve control oil circuit. The output ends of the main steam valve control oil circuit, the regulating valve control oil circuit, and the shutdown control oil circuit are all connected to the return oil circuit.

[0041] The regulating valve control oil circuit is used to convert pressure oil into regulating oil and pulse oil, and the opening of the steam inlet regulating valve 2 is adjusted by the regulating oil and pulse oil together.

[0042] The main steam valve control oil circuit is used to convert pressure oil into multi-output safety oil. One safety oil is used to control the opening and closing state of the main steam valve, and another safety oil is released to the return oil circuit through the control pulse oil to close the steam inlet regulating valve 2.

[0043] The shutdown control oil circuit is connected to the pressure oil and safety oil lines 14, and is used to achieve shutdown by releasing the pressure oil and safety oil to the return oil line.

[0044] It is understood that the low-pressure electronic control system for high-speed units provided in this embodiment only requires one pressure oil source. The input end of the regulating valve control oil circuit is connected to the gearbox main oil pump through pressure oil pipeline 9, and the main steam valve control oil circuit is connected to the gearbox main oil pump through pressure oil pipeline 13. The power oil for the entire control system is supplied by the gearbox main oil pump or the high-pressure starting oil pump. The oil pressure of the entire system is approximately 1.0 MPa. The control oil and lubricating oil of the low-pressure electronic control system can share the same oil source. The control oil is supplied by the gearbox main oil pump or the high-pressure starting oil pump, which can realize the control of the main steam valve and the steam inlet regulating valve 2 of the high-speed steam turbine, as well as the shutdown control, thus reducing equipment costs. Moreover, this system can be controlled by low-pressure oil, which also reduces the requirements for oil quality of hydraulic components and has high oil contamination resistance, thus reducing the overall production, testing and maintenance costs.

[0045] Based on the above technical solution, this embodiment can be further improved as follows.

[0046] In one implementation, such as Figure 1 and Figure 2 As shown, the regulating valve control oil circuit includes an oil filter 8, a throttle valve actuator 3, a servo valve 6, and an unloading valve 1. It is used to filter the pressure oil to become regulating oil that meets the oil quality precision requirements. The servo valve 6 and the throttle valve actuator 3 are respectively connected to the output end of the oil filter 8 through the regulating oil pipeline 4. The servo valve 6 is used to convert the regulating oil into pulse oil. The output end of the servo valve 6 is connected to the slide valve control end of the throttle valve actuator 3 through the pulse oil pipeline 5. The throttle valve actuator 3 is used to control the opening degree of the steam inlet regulating valve 2 according to the regulating oil and the pulse oil. One end of the unloading valve 1's switching channel is connected to the pulse oil pipeline 5, and the other end is connected to the return oil line. The unloading valve 1 is used to release the pulse oil to close the throttle valve actuator 3, thereby closing the steam inlet regulating valve 2.

[0047] It is understood that the oil filter 8 is connected to the main oil pump of the gearbox via the pressure oil pipeline 9, serving as the pressure oil source. The oil filter 8 can be a double-cylinder oil filter, which filters the pressure oil entering the control oil circuit of the regulating valve to remove impurities and protect subsequent hydraulic components. The regulating oil provides power for the operation of the throttle valve actuator 3. The servo valve 6 converts the regulating oil into pulse oil according to the received servo signal. The pulse oil is used to control the position of the slide valve in the throttle valve actuator 3, thereby controlling the position of the piston in the actuator. The change in the position of the actuator piston corresponds to the change in the opening of the steam inlet regulating valve 2, for example, an increase or decrease in the steam inlet flow. During normal operation, the unloading valve 1 is in the closed state. When a shutdown is required, the unloading valve 1 opens to relieve the pressure of the pulse oil, causing the throttle valve actuator 3 to control the steam inlet regulating valve 2 to close. The specific structure and working principle of the throttle valve actuator 3 are common knowledge in the field, and this embodiment only provides a brief description as follows.

[0048] The throttle valve and the hydraulic actuator are housed in the same casing, forming the throttle valve hydraulic actuator 3. Regulating oil flows through the upper window of the sleeve to the lower chamber of the hydraulic actuator piston; while regulating oil flows through the lower window to the upper chamber of the hydraulic actuator piston. The lower end of the spool valve of the throttle valve hydraulic actuator 3 is connected to the pulse oil circuit, and the upper annular chamber is connected to the high-pressure oil. When the unit load is stable, the spool valve is in the middle position, closing the windows leading to the upper and lower chambers of the hydraulic actuator piston. When the pulse oil pressure decreases (increases), the spool valve moves down (up), opening the window leading to the lower (upper) chamber of the hydraulic actuator piston, causing the regulating steam valve to close less (open more). When the hydraulic actuator actuates, the oil discharged from the upper or lower chamber of the piston flows out through the throttle valve window. By controlling the piston displacement, the opening of the steam inlet regulating valve 2 can be controlled.

[0049] In one implementation, such as Figure 2 As shown, the pulse oil output end of the servo valve 6 and the pulse oil input end of the throttle valve 3 are also connected to the regulating oil line 4 through a throttle branch, and a throttle orifice plate 17 is connected in series in the throttle branch.

[0050] It is understandable that by connecting the regulating oil in the regulating oil line 4 to the pulse oil input terminal of the throttle actuator 3 through the throttle branch, the throttle branch provides a base oil pressure for the spool valve control of the throttle actuator 3. The pressure of the pulse oil is then superimposed on the base oil pressure to achieve more precise control of the throttle actuator 3. The throttle orifice plate 17 is zero at the factory. During commissioning, an appropriate size throttle orifice can be opened according to the actual situation. For example, the size of the throttle orifice plate 17 can be set according to the required base oil pressure.

[0051] In one implementation, such as Figure 2 As shown, a pulse oil pressure regulating branch is provided between the pulse oil output end of the servo valve 6 and the return oil circuit. A throttle valve 7 is provided in the pressure regulating branch to control the discharge of pulse oil when the servo valve 6 is adjusted to zero position.

[0052] Understandably, the pulse oil pressure regulating branch is mainly used to control the oil pressure of the pulse oil, such as adjusting the zero position of servo valve 6, i.e., the oil pressure when servo valve 6 is at zero position. The flow rate of throttle valve 7 can be adjusted by controlling the throttle cross-section or throttle length of throttle valve 7, and the oil pressure of the pulse oil pressure regulating branch can be controlled by adjusting the flow rate of throttle valve 7.

[0053] In one implementation, such as Figure 2 As shown, the pulse oil output end of the servo valve 6 (corresponding to the pulse oil pipeline 5) is also equipped with a pulse oil measuring point to monitor the oil pressure of the pulse oil.

[0054] Understandably, the oil pressure of the pulse oil can be monitored in real time through the pulse oil measuring point. For example, a hydraulic testing instrument can be installed to achieve precise control of the throttle motor 3.

[0055] In one implementation, such as Figure 1 and Figure 2 As shown, the main steam valve control oil circuit includes a gate solenoid valve 11 and an automatic shut-off device 16. The gate solenoid valve 11 is used to convert pressure oil into safety oil and output it to the automatic shut-off device 16 and the unloading valve 1 through two safety oil lines 14 respectively. The automatic shut-off device 16 is used to open the main steam valve according to the pressure of the safety oil. The control end of the unloading valve 1 is connected to the safety oil line 14. The two ends of the unloading valve 1 are connected to the pulse oil line 5 and the return oil line respectively. It is used to close the channel between the pulse oil line 5 and the return oil line when the pressure of the safety oil is high, and to open the channel between the pulse oil line 5 and the return oil line when the pressure of the safety oil decreases.

[0056] Understandably, the gate solenoid valve 11 has multiple output terminals to achieve multi-channel output of safety oil. For example, the gate solenoid valve 11 can be implemented using a two-position four-way valve. Figure 2As shown, the automatic shut-off device 16 uses safety oil to drive its internal piston rod to move, thereby controlling the opening and closing of the main steam valve. It is a hydraulically controlled piston structure. When the automatic shut-off device 16 is not working, it is in a normally closed state to close the main steam valve. When a certain pressure of safety oil is applied, it can open the main steam valve. The unloading valve 1 is hydraulically controlled by safety oil to open and close, mainly used to control the release of pulse oil. When the steam inlet regulating valve 2 is working normally, the unloading valve 1 is closed under the control of safety oil. At this time, the pulse oil enters the throttle valve actuator 3 to control its operation, thereby adjusting the opening of the steam inlet regulating valve 2. When it is necessary to stop the machine, the safety oil is released into the return oil circuit. At this time, due to the decrease in safety oil pressure at the control end of the unloading valve 1, the unloading valve 1 opens, releasing the pulse oil into the return oil circuit, thereby causing the throttle valve actuator 3 to return to the closed position to close the steam inlet regulating valve 2. The setting of the unloading valve 1 realizes that the closing of the main steam valve drives the closing of the steam inlet regulating valve 2.

[0057] In one implementation, such as Figure 1 and Figure 2 As shown, a tightness test solenoid valve 15 is also provided in the safety oil line 14 between the output end of the brake solenoid valve 11 and the input end of the automatic shut-off device 16. The tightness test solenoid valve 15 has two sets of switching channels with opposite switching states. The first set of switching channels is connected to the safety oil line 14 between the output end of the brake solenoid valve 11 and the input end of the automatic shut-off device 16, and the second set of switching channels is connected to the safety oil line 14 at the input end of the automatic shut-off device 16 and the return oil line. During normal operation, the first set of switching channels of the tightness test solenoid valve 15 is turned on and the second set of switching channels is turned off. When a tightness test is performed, the second set of switching channels of the tightness test solenoid valve 15 is turned on and the first set of switching channels is turned off.

[0058] It is understandable that when the tightness test solenoid valve 15 receives the test control signal, it can switch the on / off state of the two sets of switching channels of the tightness test solenoid valve 15 to realize the tightness test of the safety oil pipeline 14 of the low-voltage electric control system. Its operation is simple and easy to implement.

[0059] In one implementation, such as Figure 1 and Figure 2 As shown, the shutdown control oil circuit includes an AST solenoid valve assembly 10. The AST solenoid valve assembly 10 has at least two independent switching channels. The first set of switching channels is connected to the pressure oil line 13 and the return oil line, and the second set of switching channels is connected to the safety oil line 14 and the return oil line, for releasing pressure oil and / or safety oil according to the shutdown signal.

[0060] Understandably, the AST solenoid valve assembly 10 is remotely controlled by signals to control its switching and sequence. The tightness test solenoid valve 15, the trip solenoid valve 11, the automatic shut-off device 16, and the steam inlet regulating valve 2 are all controlled by the AST solenoid valve assembly 10 to perform functions such as tightness testing, tripping, shutdown, and online operation testing of the AST solenoid valves. During normal system operation, both the first and second sets of switching channels of the AST solenoid valve assembly 10 are normally closed. When the AST solenoid valve assembly 10 receives a shutdown signal, it opens the first and second set of switch channels according to the shutdown signal, releasing the pressure oil and safety oil to the return oil circuit. At this time, the safety oil pressure drops rapidly and is insufficient to drive the automatic shut-off device 16 to open, so the main steam valve closes. Also, due to the decrease in safety oil pressure, the unloading valve 1's channel changes from closed to open, thereby releasing the pulse oil in the pulse oil pipeline 5, causing the steam inlet regulating valve 2 to close. Since the first switch channel releases the pressure oil to the return oil circuit, no new pressure oil enters the regulating valve control oil circuit and the main steam valve control oil circuit, thus achieving the overall shutdown of the turbine unit.

[0061] In one implementation, such as Figure 1 and Figure 2 As shown, the AST solenoid valve assembly 10 includes multiple AST solenoid valves arranged in parallel. Each AST solenoid valve is a four-position two-way valve, and each AST solenoid valve has two sets of independent switching channels.

[0062] Understandably, setting up multiple AST solenoid valves in parallel, with redundancy between them, improves the reliability of system operation. The AST solenoid valves are constantly energized and actuate upon de-energization; after an AST solenoid valve de-energizes, the main steam valve and the make-up steam valve can close within 0.5 seconds.

[0063] In one implementation, such as Figure 1 and Figure 2 As shown, the shutdown control oil circuit also includes a manual gate valve 12, which has at least one set of switching channels. The switching channels are connected to the safety oil pipeline and the return oil pipeline, and are used to release the safety oil by manually operating the actuator.

[0064] Understandably, the manual gate valve 12 provides a manual shutdown method, which enriches the system's operation methods and enhances the system's reliability and safety.

[0065] This invention provides a low-voltage electrical control system for high-speed generator units, applicable to the steam turbine industry. Its main function is to control the unit's speed and power, thereby ensuring stable operation and adjusting the electrical load. In case of abnormal conditions, it quickly closes the main steam valve and regulating valve to achieve an emergency shutdown.

[0066] The speed control section of the regulating system adjusts the turbine's steam flow by opening or closing the inlet steam regulating valve 2, thereby adjusting the unit's speed or electrical load to adapt to changes in electrical load. Specifically, when the turbine speed changes, the input speed detection signal is compared with the setpoint, outputting a deviation value. After amplification, this deviation is output as a ±10V control signal to the servo valve 6. The pulse oil output from the servo valve 6 acts on the lower part of the slide valve of the throttle actuator 3, thereby controlling the displacement of the high-pressure hydraulic actuator and changing the valve position of the inlet steam regulating valve 2, thus achieving the purpose of adjusting the opening degree of the inlet steam regulating valve 2. This regulating system is then put into the power control loop to achieve the purpose of power frequency electro-hydraulic regulation.

[0067] Working principle of the regulation system:

[0068] 1. The pressure oil is divided into two paths. One path of pressure oil enters the solenoid valve 11 through the pressure oil pipeline 13 to form safety oil, which controls the opening and closing of the automatic shut-off device 16 and the unloading valve 1 in the steam inlet regulating valve 2. The other path of pressure oil enters the oil filter 8 through the pressure oil pipeline 9 to form regulating oil. Part of the regulating oil then passes through the servo valve 6 to form pulse oil. The regulating oil and pulse oil control the opening and closing of the throttle valve motor 3.

[0069] 2. The oil pipeline is equipped with a tightness test solenoid valve 15, a trip solenoid valve 11, an AST solenoid valve assembly 10, and a manual trip valve 12. Among them, the tightness test solenoid valve 15, the trip solenoid valve 11, and the AST solenoid valve assembly 10 are all solenoid valves that can be controlled by remote signals, which can realize the tightness test of the steam turbine, remote tripping, and remote shutdown. The manual trip valve 12 can be manually tripped on site to stop the steam turbine.

[0070] 3. The steam inlet regulating valve 2 is an integrated design, comprising a throttle actuator 3, a servo valve 6, an unloading valve 1, and a throttle valve 7. It is connected to other parts of the low-pressure electric control system via a safety oil line 14, a regulating oil line 4, and a return oil line. Regulating oil enters the steam inlet regulating valve 2 and is divided into two paths: one enters the piston chamber of the throttle actuator 3, and the other enters the servo valve 6 to form pulse oil, which enters the lower end of the spool valve of the throttle actuator 3. The servo valve 6 controls the magnitude of the pulse oil pressure to adjust the rise and fall of the spool valve, thereby controlling the flow of regulating oil to the upper or lower end of the piston, and thus controlling the opening and closing of the regulating valve. The unloading valve 1 is controlled by safety oil. When the steam inlet regulating valve 2 needs to be closed, the safety oil is released, causing the unloading valve 1 to open, thus releasing the pulse oil and closing the steam inlet regulating valve 2. The throttle valve 7 adjusts the zero position of the servo valve 6 by adjusting the discharge of the pulse oil.

[0071] The following example illustrates the workflow in a specific use case.

[0072] 1) When the steam turbine is ready to start up, the pressure oil of the regulating system is supplied by the AC electric oil pump. During startup, as the steam turbine speed gradually increases, the pressure of the gearbox main oil pump becomes greater than the pressure of the AC electric oil pump, and at this time, the pressure oil of the regulating system is supplied by the gearbox main oil pump.

[0073] 2) The computer sends a signal to the solenoid valve 11, which is energized and actuates. One line of pressure oil enters the pressure oil pipeline 13 and forms two lines of safety oil after passing through the solenoid valve 11. One line of safety oil goes to the automatic shut-off device 16 to open the main steam valve; the other line of safety oil goes to the unloading valve 1 in the steam inlet regulating valve 2 to close the unloading valve 1.

[0074] Meanwhile, another pressure oil enters the pressure oil line 9, and becomes regulating oil after passing through the double-cylinder oil filter. Since the unloading valve 1 has been closed, pulse oil can be established at this time.

[0075] 3) The computer sends a signal to the servo valve 6, which adjusts the opening of the throttle actuator 3 by controlling the pulse oil pressure.

[0076] Steps 1) to 3) above constitute the main process of stable operation of a high-speed steam turbine.

[0077] 4) During normal unit operation, the tightness test solenoid valve 15 is in the safety oil connection state, at which time the safety oil pressure is normal and the main steam valve is in the open state. When the tightness test is performed, the computer sends a signal to the tightness test solenoid valve 15, the tightness test solenoid valve 15 is energized and activated, the safety oil of the automatic shut-off device 16 is connected to the return oil line, the safety oil is discharged, and the main steam valve is closed. At this time, the safety oil that was originally connected to the automatic shut-off device 16 is cut off at the tightness test solenoid valve 15, the safety oil pressure remains unchanged, and it does not affect other parts of the unit (such as the steam inlet regulating valve 2).

[0078] 5) When the AST solenoid valve assembly 10 receives the shutdown signal, the safety oil is released through the AST solenoid valve assembly 10 and the main steam valve is closed; at the same time, the pulse oil is released through the unloading valve 1, the throttle valve motor 3 is closed, the steam inlet regulating valve 2 is closed, and the steam turbine is shut down.

[0079] 6) When manual tripping is required, move the handle on the manual tripping valve 12. The safety oil is released through the manual tripping valve 12, and the main steam valve is closed. At the same time, the pulse oil is released through the unloading valve 1, the throttle valve motor 3 is closed, the steam inlet regulating valve 2 is closed, and the steam turbine is shut down.

[0080] This system is suitable for high-speed steam turbines and features low cost, high automation, and high reliability. Furthermore, the system can be easily modified for use with other types of steam turbines, demonstrating good compatibility.

[0081] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A low-voltage electronic control system for high-speed generator sets, characterized in that, It includes a main steam valve control oil circuit, a regulating valve control oil circuit, and a shutdown control oil circuit. The input ends of the main steam valve control oil circuit and the regulating valve control oil circuit are connected to the same pressure oil source. The input end of the shutdown control oil circuit is connected to the main steam valve control oil circuit. The output ends of the main steam valve control oil circuit, the regulating valve control oil circuit, and the shutdown control oil circuit are all connected to the return oil circuit. The regulating valve control oil circuit is used to convert pressure oil into regulating oil and pulse oil, and the opening degree of the steam inlet regulating valve (2) is adjusted by the regulating oil and pulse oil together. The main steam valve control oil circuit is used to convert pressure oil into multi-output safety oil. One safety oil is used to control the opening and closing state of the main steam valve, and another safety oil is discharged to the return oil circuit through the control pulse oil to close the steam inlet regulating valve (2). The shutdown control oil circuit is connected to the pressure oil and safety oil line (14) and is used to achieve shutdown by releasing the pressure oil and safety oil to the return oil line.

2. The low-voltage electronic control system for high-speed generator units according to claim 1, characterized in that, The regulating valve control oil circuit includes an oil filter (8), a throttle valve actuator (3), a servo valve (6), and an unloading valve (1). The oil filter (8) is used to filter the pressure oil into regulating oil that meets the oil quality accuracy requirements. The servo valve (6) is used to convert the regulating oil into pulse oil. The throttle valve actuator (3) is used to control the opening of the steam inlet regulating valve (2) according to the regulating oil and pulse oil. The unloading valve (1) is used to release the pulse oil to close the steam inlet regulating valve (2).

3. A low-voltage electronic control system for high-speed generator units according to claim 2, characterized in that, The pulse oil output end of the servo valve (6) and the pulse oil input end of the throttle valve actuator (3) are also connected to the regulating oil pipeline (4) through a throttle branch, and a throttle orifice plate (17) is connected in series in the throttle branch.

4. A low-voltage electronic control system for high-speed generator units according to claim 3, characterized in that, The servo valve (6) is provided with a pulse oil pressure regulating branch between the pulse oil output end and the return oil circuit. The pressure regulating branch is provided with a throttle valve (7) for controlling the discharge of pulse oil when the servo valve (6) is adjusted to zero position.

5. A low-voltage electronic control system for high-speed generator units according to claim 4, characterized in that, The servo valve (6) is also equipped with a pulse oil measuring point at its pulse oil output end to monitor the oil pressure of the pulse oil.

6. A low-voltage electronic control system for high-speed generator units according to any one of claims 2 to 5, characterized in that, The main steam valve control oil circuit includes a gate solenoid valve (11) and an automatic shut-off device (16). The gate solenoid valve (11) is used to convert pressure oil into safety oil and output it to the automatic shut-off device (16) and the unloading valve (1) through pipelines. The automatic shut-off device (16) is used to open the main steam valve according to the pressure of the safety oil. The control end of the unloading valve (1) is connected to the safety oil pipeline (14). The two ends of the unloading valve (1) are connected to the pulse oil pipeline (5) and the return oil pipeline, respectively. It is used to close the channel between the pulse oil pipeline (5) and the return oil pipeline when the pressure of the safety oil is high, and to open the channel between the pulse oil pipeline (5) and the return oil pipeline when the pressure of the safety oil is low.

7. A low-voltage electronic control system for high-speed generator units according to claim 6, characterized in that, A tightness test solenoid valve (15) is also provided in the safety oil line (14) between the output end of the solenoid valve (11) and the input end of the automatic shut-off device (16). The tightness test solenoid valve (15) has two sets of switching channels with opposite switching states. The first set of switching channels is connected to the safety oil line (14) between the output end of the solenoid valve (11) and the input end of the automatic shut-off device (16). The second set of switching channels is connected to the safety oil line (14) at the input end of the automatic shut-off device (16) and the return oil line. When working normally, the first set of switching channels of the tightness test solenoid valve (15) is turned on and the second set of switching channels is turned off. When a tightness test is performed, the second set of switching channels of the tightness test solenoid valve (15) is turned on and the first set of switching channels is turned off.

8. A low-voltage electronic control system for high-speed generator units according to claim 6 or 7, characterized in that, The shutdown control oil circuit includes an AST solenoid valve assembly (10), which has at least two independent switching channels. The first set of switching channels is connected to the pressure oil line (13) and the return oil line, and the second set of switching channels is connected to the safety oil line (14) and the return oil line, for releasing pressure oil and / or safety oil according to the shutdown signal.

9. A low-voltage electronic control system for high-speed generator units according to claim 8, characterized in that, The AST solenoid valve assembly (10) includes multiple AST solenoid valves arranged in parallel. Each AST solenoid valve is a four-position two-way valve, and each AST solenoid valve has two independent switching channels.

10. A low-voltage electronic control system for high-speed generator units according to claim 8 or 9, characterized in that, The shutdown control oil circuit also includes a manual gate valve (12), which has at least one set of switching channels. The switching channels are connected to the safety oil line (14) and the return oil line, and are used to release safety oil by manually operating the actuator.

Images