Overspeed protection system for hydropower station unit

Abstract

The invention provides an over-speed protection system for a hydropower station unit. The over-speed protection system comprises a hydraulic control valve group and a mechanical hydraulic over-speed protection device, the oil input end of the hydraulic control valve group is connected with the oil output end of the proportional valve group, and the oil output end of the hydraulic control valve group is connected with the control input end of the distributing valve group; the power input end of the mechanical hydraulic over-speed protection device is connected with the power output end of a rotating shaft in the unit, and the oil liquid output end of the mechanical hydraulic over-speed protection device is connected with the control input end of the hydraulic control valve group; the mechanical hydraulic overspeed protection device is used for stopping supplying pressure oil to the control input end of the hydraulic control valve set when the actual rotating speed of a rotating shaft in the unit exceeds the preset rotating speed, so that the hydraulic control valve set cuts off a channel between the oil output end of the proportional valve set and the control input end of the distributing valve set. According to the overspeed protection system for the hydropower station unit, the electrical control system is independent of the unit, control logic and pipeline distribution are simplified, and the failure risk of the system is greatly reduced.

Description

Technical Field

[0001] This disclosure relates to the technical field of hydropower station speed governor systems, and in particular to an overspeed protection system for hydropower station units. Background Technology

[0002] The core function of the governor control system is to maintain the stability of the generator speed and the grid frequency. It is the "nerve center" and "intelligent heart" of the hydropower station, directly affecting the safety, stability, efficiency, and power quality of the station. Current governor control systems use emergency pressure regulating valves for overspeed protection. However, this method makes the system more complex, involves numerous pipelines, and requires additional adjustment of the closing time. Currently, emergency pressure regulating valves primarily use springs to adjust the closing time. As operating time increases, changes in spring elasticity lead to longer closing times, increasing the risk of failure. Summary of the Invention

[0003] This disclosure aims to at least partially address one of the technical problems in the related art.

[0004] Therefore, the purpose of this disclosure is to provide an overspeed protection system for hydropower station units.

[0005] To achieve the above objectives, this disclosure provides an overspeed protection system for a hydropower station unit, comprising: a hydraulic control valve group and a mechanical-hydraulic overspeed protection device; the hydraulic control valve group's oil input end is connected to the oil output end of a proportional valve group, and the hydraulic control valve group's oil output end is connected to the control input end of a pressure distribution valve group, wherein the proportional valve group is used to control the oil pressure at the control input end of the pressure distribution valve group, so that the pressure distribution valve group controls the opening degree of the guide vanes in the unit; the mechanical-hydraulic overspeed protection device's power input end is connected to the power output end of the unit's rotating shaft, and pressurized oil is supplied to the hydraulic control valve group's oil input end, and the hydraulic control valve group's oil output end is connected to the control input end of the hydraulic control valve group; wherein the mechanical-hydraulic overspeed protection device is used to stop supplying pressurized oil to the control input end of the hydraulic control valve group when the actual rotational speed of the unit's rotating shaft exceeds a preset speed, so that the hydraulic control valve group cuts off the passage between the proportional valve group's oil output end and the pressure distribution valve group's control input end.

[0006] Optionally, the hydraulic control valve assembly includes: a hydraulic directional valve, wherein the P port of the hydraulic directional valve is connected to the oil output terminal of the proportional valve assembly, and the T port of the hydraulic directional valve is connected to the oil tank; the B port of the hydraulic directional valve is connected to the control input terminal of the pressure regulating valve assembly; and the X port of the hydraulic directional valve is connected to the oil output terminal of the mechanical hydraulic overspeed protection device; wherein the hydraulic directional valve is used to open the P port and the B port when the X port receives pressurized oil supplied by the mechanical hydraulic overspeed protection device, and to open the T port and the B port when the X port does not receive pressurized oil supplied by the mechanical hydraulic overspeed protection device.

[0007] Optionally, the proportional valve assembly includes: a first servo proportional valve and a second servo proportional valve; wherein, the P port of the first servo proportional valve is supplied with pressurized oil, and the T port of the first servo proportional valve is connected to an oil tank, and the A port of the first servo proportional valve is connected to the P port of the hydraulic directional valve; the P port of the second servo proportional valve is supplied with pressurized oil, and the T port of the second servo proportional valve is connected to an oil tank, and the A port of the second servo proportional valve is connected to the T port of the hydraulic directional valve.

[0008] Optionally, the proportional valve assembly further includes: a first solenoid directional valve, which is disposed between the hydraulically controlled directional valve and the proportional valve assembly, wherein the P port of the first solenoid directional valve is connected to the A port of the first servo proportional valve, the T port of the first solenoid directional valve is connected to the A port of the second servo proportional valve, and the A port of the first solenoid directional valve is connected to the P port of the hydraulically controlled directional valve; wherein the first solenoid directional valve is used to connect the P port and the A port of the first solenoid directional valve, or to connect the T port and the A port of the first solenoid directional valve.

[0009] Optionally, the system further includes: a second solenoid directional valve, which is disposed between the hydraulic directional valve and the first solenoid directional valve, and the P port of the second solenoid directional valve is connected to the A port of the first solenoid directional valve, the T port of the second solenoid directional valve is connected to the oil tank, and the A port of the second solenoid directional valve is connected to the P port of the hydraulic directional valve; wherein, the second solenoid directional valve is used to open the P port and the A port of the second solenoid directional valve, or to open the T port and the A port of the second solenoid directional valve.

[0010] Optionally, the system further includes: a third electromagnetic directional valve, wherein the third electromagnetic directional valve is disposed between the hydraulically controlled directional valve and the second electromagnetic directional valve, and the P port of the third electromagnetic directional valve is connected to the A port of the second electromagnetic directional valve, the T port of the third electromagnetic directional valve is connected to the oil tank, and the A port of the third electromagnetic directional valve is connected to the P port of the hydraulically controlled directional valve; wherein the third electromagnetic directional valve is used to connect the P port and the A port of the third electromagnetic directional valve, or to connect the T port and the A port of the third electromagnetic directional valve.

[0011] Optionally, the system further includes: a hydraulic integrated block, wherein the pressure regulating valve group is disposed within the hydraulic integrated block, and the hydraulically controlled directional valve, the first solenoid directional valve, the second solenoid directional valve, the third solenoid directional valve, the first servo proportional valve, and the second servo proportional valve are sequentially and alternately disposed on the hydraulic integrated block.

[0012] Optionally, the mechanical hydraulic overspeed protection device includes: an overspeed detector and an overspeed valve; the power input terminal of the overspeed detector is connected to the power output terminal of the unit's rotating shaft, and the power output terminal of the overspeed detector is connected to the power input terminal of the overspeed valve; pressurized oil is supplied to the P port of the overspeed valve, and the A port of the overspeed valve is connected to the X port of the hydraulic control valve assembly, and the T port of the overspeed valve is connected to the oil tank; wherein, the overspeed valve is used to supply pressurized oil to the X port of the hydraulic control valve assembly when the actual rotational speed of the unit's rotating shaft does not exceed the preset speed, so as to open the P port and B port of the hydraulic control directional valve; and, when the actual rotational speed of the unit's rotating shaft exceeds the preset speed, to stop supplying pressurized oil to the X port of the hydraulic control valve assembly, so as to open the T port and B port of the hydraulic control directional valve.

[0013] Optionally, the system further includes a monitoring module, the signal input terminal of which is connected to the signal output terminal of the mechanical hydraulic overspeed protection device, and the mechanical hydraulic overspeed protection device is used to send a warning signal to the monitoring module when the actual rotational speed of the rotating shaft in the unit exceeds the preset speed.

[0014] Optionally, the system further includes a pressure detection unit, the oil input terminal of which is connected to the oil input terminal of the pressure regulating valve group and the oil input terminal of the proportional valve group, respectively, and the pressure detection unit is used to detect the pressure of the pressure oil.

[0015] The technical solution provided in this disclosure may include the following beneficial effects: When the actual rotational speed of the unit's central shaft exceeds the preset speed, the mechanical-hydraulic overspeed protection device stops supplying pressurized oil to the control input of the hydraulic control valve group. This causes the hydraulic control valve group to cut off the passage between the oil output of the proportional valve group and the control input of the pressure distribution valve group, thereby achieving unit shutdown protection. Furthermore, the pure hydraulic overspeed protection structure, which combines the hydraulic control valve group and the mechanical-hydraulic overspeed protection device, is independent of the unit's electrical control system. This not only simplifies the control logic and pipeline distribution but also avoids additional shutdown time adjustments, significantly reducing the risk of system failure.

[0016] Additional aspects and advantages of this disclosure will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this disclosure. Attached Figure Description

[0017] The above and / or additional aspects and advantages of this disclosure will become apparent and readily understood from the following description of the embodiments taken in conjunction with the accompanying drawings, in which: Figure 1 This is a schematic diagram of the oil circuit of an overspeed protection system for a hydropower station unit according to an embodiment of this disclosure; Figure 2 This is a schematic diagram of the structure of a hydropower station unit overspeed protection system according to an embodiment of this disclosure; As shown in the figure: 1. Hydraulic control valve assembly, 11. Hydraulic control directional valve; 2. Mechanical hydraulic overspeed protection device; 21. Overspeed detector; 22. Overspeed valve; 3. Proportional valve assembly; 31. First servo proportional valve; 32. Second servo proportional valve; 33. First solenoid directional valve. 4. Pressure regulating valve assembly; 5. Second solenoid directional valve; 6. Third solenoid directional valve; 7. Hydraulic manifold; 8. Pressure detection unit. Detailed Implementation

[0018] Embodiments of this disclosure are described in detail below, examples of which are illustrated 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 are used only to explain this disclosure, and should not be construed as limiting this disclosure. Rather, embodiments of this disclosure include all variations, modifications, and equivalents falling within the spirit and scope of the appended claims.

[0019] like Figure 1As shown in the figure, this disclosure proposes an overspeed protection system for a hydropower station unit, including: a hydraulic control valve group 1 and a mechanical-hydraulic overspeed protection device 2. The oil input end of the hydraulic control valve group 1 is connected to the oil output end of a proportional valve group 3, and the oil output end of the hydraulic control valve group 1 is connected to the control input end of a pressure distribution valve group 4. The proportional valve group 3 controls the oil pressure at the control input end of the pressure distribution valve group 4, so that the pressure distribution valve group 4 controls the opening of the guide vanes in the unit. The power input end of the mechanical-hydraulic overspeed protection device 2 is connected to the power output end of the unit's rotating shaft, and pressurized oil is supplied to the oil input end of the mechanical-hydraulic overspeed protection device 2. The oil output end of the mechanical-hydraulic overspeed protection device 2 is connected to the control input end of the hydraulic control valve group 1. The mechanical-hydraulic overspeed protection device 2 stops supplying pressurized oil to the control input end of the hydraulic control valve group 1 when the actual rotational speed of the unit's rotating shaft exceeds a preset speed, so that the hydraulic control valve group 1 cuts off the passage between the oil output end of the proportional valve group 3 and the control input end of the pressure distribution valve group 4.

[0020] Understandably, since the hydraulic input end of the hydraulic control valve group 1 is connected to the hydraulic output end of the proportional valve group 3, and the hydraulic output end of the hydraulic control valve group 1 is connected to the control input end of the pressure regulating valve group 4, the hydraulic control valve group 1 can selectively open the passage between the hydraulic output end of the proportional valve group 3 and the control input end of the pressure regulating valve group 4. Furthermore, since the power input end of the mechanical hydraulic overspeed protection device 2 is connected to the power output end of the unit's central shaft, and pressurized oil is supplied to the hydraulic input end of the mechanical hydraulic overspeed protection device 2, and the hydraulic output end of the mechanical hydraulic overspeed protection device 2 is connected to the control input end of the hydraulic control valve group 1, the mechanical hydraulic overspeed protection device 2 can obtain the rotation state of the unit's central shaft and selectively open the passage between the pressurized oil and the control input end of the hydraulic control valve group 1.

[0021] Specifically, when the actual rotational speed of the unit's central shaft exceeds the preset speed, the mechanical hydraulic overspeed protection device 2 stops supplying pressurized oil to the control input of the hydraulic control valve group 1, thereby cutting off the passage between the oil output of the proportional valve group 3 and the control input of the pressure distribution valve group 4, thus achieving unit shutdown protection. Furthermore, the pure hydraulic overspeed protection structure, which combines the hydraulic control valve group 1 and the mechanical hydraulic overspeed protection device 2, is independent of the unit's electrical control system. This not only simplifies the control logic and pipeline distribution but also avoids additional shutdown time adjustments, significantly reducing the risk of system failure.

[0022] It should be noted that the pure hydraulic protection circuit consisting of the hydraulic control valve group 1 and the mechanical hydraulic overspeed protection device 2 is simple and reliable to control, and is easy to troubleshoot even if the mechanical part fails; it has a simple structure and is easy to directly modify the original scheme; it is not prone to failure and does not require regular maintenance such as adjusting the closing time; it is independent of the electrical control system, avoiding more serious power production accidents caused by the failure of the speed controller system due to power failure.

[0023] The proportional valve assembly 3 controls the oil pressure at the input end of the pressure regulating valve assembly 4, which in turn controls the servo mechanism of the guide vanes in the unit to adjust the guide vane opening. The specific types of the proportional valve assembly 3 and the pressure regulating valve assembly 4 can be configured according to actual needs and are not restricted in this regard.

[0024] The hydraulic control valve group 1 is used to selectively open the passage between the oil output end of the proportional valve group 3 and the control input end of the pressure regulating valve group 4. Specifically, when pressurized oil is supplied to the control input end of the hydraulic control valve group 1, the oil input end and the oil output end of the hydraulic control valve group 1 are connected, thereby opening the passage between the oil output end of the proportional valve group 3 and the control input end of the pressure regulating valve group 4. When pressurized oil is not supplied to the control input end of the hydraulic control valve group 1, the oil input end and the oil output end of the hydraulic control valve group 1 are closed, thereby cutting off the passage between the oil output end of the proportional valve group 3 and the control input end of the pressure regulating valve group 4. The specific type of the hydraulic control valve group 1 can be set according to actual needs and is not limited thereto.

[0025] The mechanical-hydraulic overspeed protection device 2 is used to control the rotational speed of the unit's shaft by adjusting the oil circuit based on mechanical transmission. Specifically, when the actual rotational speed of the unit's shaft does not exceed the preset speed, pressurized oil is supplied to the control input terminal of the hydraulic control valve group 1; conversely, when the actual rotational speed of the unit's shaft exceeds the preset speed, the supply of pressurized oil to the control input terminal of the hydraulic control valve group 1 is stopped. The specific type of the mechanical-hydraulic overspeed protection device 2 can be set according to actual needs and is not limited thereto.

[0026] like Figure 1 As shown, in some embodiments, the hydraulic control valve assembly 1 includes: a hydraulic control directional valve 11, the P port of which is connected to the oil output terminal of the proportional valve assembly 3, and the T port of which is connected to the oil tank; the B port of which is connected to the control input terminal of the pressure regulating valve assembly 4; and the X port of which is connected to the oil output terminal of the mechanical hydraulic overspeed protection device 2. Specifically, the hydraulic control directional valve 11 is used to open the P and B ports when the X port receives pressurized oil supplied by the mechanical hydraulic overspeed protection device 2, and to open the T and B ports when the X port does not receive pressurized oil supplied by the mechanical hydraulic overspeed protection device 2.

[0027] Understandably, when port X receives pressurized oil supplied by the mechanical hydraulic overspeed protection device 2, ports P and B of the hydraulic directional valve 11 are connected, thereby opening the passage between the oil output end of the proportional valve group 3 and the control input end of the pressure regulating valve group 4, thus ensuring the stable operation of the unit; when port X does not receive pressurized oil supplied by the mechanical hydraulic overspeed protection device 2, ports T and B of the hydraulic directional valve 11 are connected, thereby cutting off the passage between the oil output end of the proportional valve group 3 and the control input end of the pressure regulating valve group 4, thus realizing the overspeed protection of the unit.

[0028] It should be noted that the hydraulic directional valve 11 is a directional control valve whose valve core is driven to switch by external hydraulic oil pressure, and does not rely on an electromagnet. The hydraulic directional valve 11 is a three-position four-way hydraulic directional valve 11, with a P port, a T port, an A port, a B port, and an X port. The P port of the hydraulic directional valve 11 is used for oil supply, the T port is used for oil return, and the A and B ports are used for outputting or inputting pressurized oil. In this embodiment, the A port of the hydraulic directional valve 11 is closed and does not participate in oil control.

[0029] Specifically, when the X port of the hydraulic directional valve 11 receives the pressure oil supplied by the mechanical hydraulic overspeed protection device 2, the P port and the B port are connected; when the X port of the hydraulic directional valve 11 does not receive the pressure oil supplied by the mechanical hydraulic overspeed protection device 2, the T port and the B port are connected.

[0030] The specific type of the hydraulic directional valve 11 can be set according to actual needs, and there are no restrictions on it.

[0031] like Figure 1 As shown, in some embodiments, the proportional valve assembly 3 includes: a first servo proportional valve 31 and a second servo proportional valve 32. The P port of the first servo proportional valve 31 is supplied with pressurized oil, and its T port is connected to an oil tank. Its A port is connected to the P port of the hydraulic directional valve 11. The P port of the second servo proportional valve 32 is supplied with pressurized oil, and its T port is connected to an oil tank. Its A port is connected to the T port of the hydraulic directional valve 11.

[0032] It is understandable that by controlling the first servo proportional valve 31 and the second servo proportional valve 32, the pressure at the control input end of the pressure regulating valve group 4 can be effectively adjusted by the hydraulic directional valve 11, so that the pressure regulating valve group 4 controls the opening of the guide vanes in the unit. The specific types of the first servo proportional valve 31 and the second servo proportional valve 32 can be set according to actual needs and are not limited thereto.

[0033] It should be noted that both the first servo proportional valve 31 and the second servo proportional valve 32 are servo proportional valves. Servo proportional valves are high-performance electro-hydraulic control components that fall between ordinary proportional valves and servo valves. They are driven by proportional electromagnets and achieve closed-loop control by combining displacement / pressure feedback, thus combining the high precision of servo valves with the cost-effectiveness of proportional valves.

[0034] The servo proportional valve is a direct-acting four-position four-way high-frequency response proportional directional valve with P port, T port, A port and B port. The P port of the servo proportional valve is used for oil supply, the T port is used for oil return, and the A and B ports are used for outputting or inputting pressurized oil. In this embodiment, the B port of the servo proportional valve is closed and does not participate in oil control.

[0035] The specific types of the first servo proportional valve 31 and the second servo proportional valve 32 can be set according to actual needs, and there are no restrictions on this.

[0036] like Figure 1 As shown, in some embodiments, the proportional valve group 3 further includes a first solenoid directional valve 33. The first solenoid directional valve 33 is disposed between the hydraulically controlled directional valve 11 and the proportional valve group 3, and the P port of the first solenoid directional valve 33 is connected to the A port of the first servo proportional valve 31, the T port of the first solenoid directional valve 33 is connected to the A port of the second servo proportional valve 32, and the A port of the first solenoid directional valve 33 is connected to the P port of the hydraulically controlled directional valve 11. The first solenoid directional valve 33 is used to connect the P port and the A port, or to connect the T port and the A port.

[0037] Understandably, since the P port of the first solenoid directional valve 33 is connected to the A port of the first servo proportional valve 31, the T port of the first solenoid directional valve 33 is connected to the A port of the second servo proportional valve 32, and the A port of the first solenoid directional valve 33 is connected to the P port of the hydraulic directional valve 11, the first solenoid directional valve 33 can selectively open the passage between the hydraulic directional valve 11 and the proportional valve group 3. Specifically, when the P port and A port of the first solenoid directional valve 33 are open, the passage between the hydraulic directional valve 11 and the first servo proportional valve 31 is open; when the T port and A port of the first solenoid directional valve 33 are open, the passage between the hydraulic directional valve 11 and the second servo proportional valve 32 is open. Thus, through the cooperation of the first solenoid directional valve 33, the first servo proportional valve 31, and the second servo proportional valve 32, the stable operation of the unit is ensured.

[0038] It should be noted that the first solenoid directional valve 33 is used in conjunction with the first servo proportional valve 31 and the second servo proportional valve 32 to regulate the pressure at the control input of the pressure distribution valve group 4. The first solenoid directional valve 33 is a three-position four-way solenoid directional valve with a P port, a T port, an A port, and a B port. The P port of the first solenoid directional valve 33 is used for oil supply, the T port of the first solenoid directional valve 33 is used for oil return, and the A and B ports of the first solenoid directional valve 33 are used for outputting or inputting pressurized oil. In this embodiment, the B port of the first solenoid directional valve 33 is closed and does not participate in oil control.

[0039] Under the control of an external signal, the P port and A port of the first electromagnetic reversing valve 33 are connected, or the T port and A port are connected, or all ports are closed in the neutral position.

[0040] The specific type of the first electromagnetic directional valve 33 can be set according to actual needs, and there are no restrictions on it.

[0041] like Figure 1 As shown, in some embodiments, the system further includes a second solenoid directional valve 5, which is disposed between the hydraulic directional valve 11 and the first solenoid directional valve 33. The P port of the second solenoid directional valve 5 is connected to the A port of the first solenoid directional valve 33, the T port of the second solenoid directional valve 5 is connected to the oil tank, and the A port of the second solenoid directional valve 5 is connected to the P port of the hydraulic directional valve 11. The second solenoid directional valve 5 is used to connect the P port and the A port, or to connect the T port and the A port.

[0042] Understandably, since the P port of the second solenoid directional valve 5 is connected to the A port of the first solenoid directional valve 33, the T port of the second solenoid directional valve 5 is connected to the oil tank, and the A port of the second solenoid directional valve 5 is connected to the P port of the hydraulic control directional valve 11, the second solenoid directional valve 5 can selectively open the passage between the hydraulic control directional valve 11 and the first solenoid directional valve 33. Specifically, when the P port and A port of the second solenoid directional valve 5 are open, the passage between the hydraulic control directional valve 11 and the first solenoid directional valve 33 is open, thereby ensuring the stable operation of the unit. When the T port and A port of the second solenoid directional valve 5 are open, the passage between the hydraulic control directional valve 11 and the first solenoid directional valve 33 is cut off, thereby realizing the emergency protection of the unit.

[0043] It should be noted that the second solenoid directional valve 5 is used for emergency shut-off of the passage between the proportional valve group 3 and the pressure regulating valve group 4. The second solenoid directional valve 5 has a P port, a T port, an A port, and a B port. The P port of the second solenoid directional valve 5 is used for oil supply, the T port of the second solenoid directional valve 5 is used for oil return, and the A and B ports of the second solenoid directional valve 5 are used for outputting or inputting pressurized oil. In this embodiment, the B port of the second solenoid directional valve 5 is closed and does not participate in oil control.

[0044] Under the control of an external signal, the P port and A port of the second electromagnetic reversing valve 5 are connected, or the T port and A port are connected, or all ports are closed in the neutral position.

[0045] The specific type of the second electromagnetic reversing valve 5 can be set according to actual needs, and there are no restrictions on it.

[0046] like Figure 1 As shown, in some embodiments, the system further includes a third solenoid directional valve 6, which is disposed between the hydraulically controlled directional valve 11 and the second solenoid directional valve 5. The P port of the third solenoid directional valve 6 is connected to the A port of the second solenoid directional valve 5, the T port of the third solenoid directional valve 6 is connected to the oil tank, and the A port of the third solenoid directional valve 6 is connected to the P port of the hydraulically controlled directional valve 11. The third solenoid directional valve 6 is used to connect the P port and the A port, or to connect the T port and the A port.

[0047] Understandably, since the P port of the third solenoid directional valve 6 is connected to the A port of the second solenoid directional valve 5, the T port of the third solenoid directional valve 6 is connected to the oil tank, and the A port of the third solenoid directional valve 6 is connected to the P port of the hydraulic control directional valve 11, the third solenoid directional valve 6 can selectively open the passage between the hydraulic control directional valve 11 and the second solenoid directional valve 5. Specifically, when the P port and A port of the third solenoid directional valve 6 are open, the passage between the hydraulic control directional valve 11 and the second solenoid directional valve 5 is open, thereby ensuring the stable operation of the unit. When the T port and A port of the third solenoid directional valve 6 are open, the passage between the hydraulic control directional valve 11 and the second solenoid directional valve 5 is cut off, thereby realizing the emergency protection of the unit.

[0048] It should be noted that the third solenoid directional valve 6 is used for emergency shut-off of the passage between the proportional valve group 3 and the pressure regulating valve group 4. The third solenoid directional valve 6 has a P port, a T port, an A port, and a B port. The P port of the third solenoid directional valve 6 is used for oil supply, the T port of the third solenoid directional valve 6 is used for oil return, and the A and B ports of the third solenoid directional valve 6 are used for outputting or inputting pressurized oil. In this embodiment, the B port of the third solenoid directional valve 6 is closed and does not participate in oil control.

[0049] Under the control of an external signal, the P port and A port of the third electromagnetic reversing valve 6 are connected, or the T port and A port are connected, or all ports are closed in the neutral position.

[0050] The specific type of the third electromagnetic directional valve 6 can be set according to actual needs, and there are no restrictions on it.

[0051] like Figure 2As shown, in some embodiments, the system further includes: a hydraulic integrated block 7, a pressure regulating valve group 4 disposed within the hydraulic integrated block 7, and a hydraulically controlled directional valve 11, a first solenoid directional valve 33, a second solenoid directional valve 5, a third solenoid directional valve 6, a first servo proportional valve 31, and a second servo proportional valve 32 disposed sequentially and at intervals on the hydraulic integrated block 7.

[0052] Understandably, by utilizing the hydraulic integrated block 7, the pressure distribution valve group 4, the hydraulic control directional valve 11, the first solenoid directional valve 33, the second solenoid directional valve 5, the third solenoid directional valve 6, the first servo proportional valve 31, and the second servo proportional valve 32 can be integrated, thereby making the system more flexible and convenient to use.

[0053] It should be noted that the hydraulic integration block 7 is used to integrate the pressure distribution valve group 4, the hydraulic control directional valve 11, the first solenoid directional valve 33, the second solenoid directional valve 5, the third solenoid directional valve 6, the first servo proportional valve 31, and the second servo proportional valve 32. The specific type of the hydraulic integration block 7 can be set according to actual needs, and there are no restrictions on it.

[0054] like Figure 1 As shown, in some embodiments, the mechanical hydraulic overspeed protection device 2 includes an overspeed detector 21 and an overspeed valve 22. The power input terminal of the overspeed detector 21 is connected to the power output terminal of the unit's rotating shaft, and the power output terminal of the overspeed detector 21 is connected to the power input terminal of the overspeed valve 22. Pressure oil is supplied to the P port of the overspeed valve 22, and the A port of the overspeed valve 22 is connected to the X port of the hydraulic control valve assembly 1. The T port of the overspeed valve 22 is connected to the oil tank. Specifically, the overspeed valve 22 supplies pressure oil to the X port of the hydraulic control valve assembly 1 when the actual rotational speed of the unit's rotating shaft does not exceed a preset speed, thereby opening the P and B ports of the hydraulic control directional valve 11. Conversely, when the actual rotational speed of the unit's rotating shaft exceeds the preset speed, it stops supplying pressure oil to the X port of the hydraulic control valve assembly 1, thereby opening the T and B ports of the hydraulic control directional valve 11.

[0055] Understandably, since the power input terminal of the overspeed detector 21 is connected to the power output terminal of the unit's rotating shaft, and the power output terminal of the overspeed detector 21 is connected to the power input terminal of the overspeed valve 22, the overspeed detector 21 can transmit the rotational speed signal of the unit's rotating shaft to the overspeed valve 22 in the form of power. Furthermore, since the P port of the overspeed valve 22 is connected to pressurized oil, and the A port of the overspeed valve 22 is connected to the X port of the hydraulic control valve group 1, and the T port of the overspeed valve 22 is connected to the oil tank, the overspeed valve 22 can selectively open the passage between the pressurized oil and the control input terminal of the hydraulic control valve group 1.

[0056] Specifically, when the actual rotational speed of the unit's rotating shaft does not exceed the preset speed, the P and A ports of the overspeed valve 22 are opened, thereby supplying pressurized oil to the X port of the hydraulic control valve group 1, and thus opening the P and B ports of the hydraulic control directional valve 11 to ensure the stable operation of the unit; when the actual rotational speed of the unit's rotating shaft exceeds the preset speed, the T and A ports of the overspeed valve 22 are opened, thereby stopping the supply of pressurized oil to the X port of the hydraulic control valve group 1, and thus cutting off the P and B ports of the hydraulic control directional valve 11 to achieve overspeed protection of the unit.

[0057] It should be noted that the overspeed detector 21 is mounted on the main shaft of the turbine unit via two segmented circular flanges. The entire detector rotates synchronously with the main shaft to sense the rotational speed in real time. It includes: centrifugal block, spring, ratchet, limit shaft, etc. The overspeed valve 22 includes: cam, valve body, valve core, etc. The working principle of the overspeed detector 21 and overspeed valve 22 is as follows: When the unit shaft speed is normal, the centrifugal force of the centrifugal block of the overspeed detector 21 is less than the spring preload, the centrifugal block is stationary, the impact block presses against the valve core, and the overspeed valve 22 does not switch. When the speed exceeds the limit, the centrifugal force of the centrifugal block overcomes the spring force and slides outward radially. The centrifugal block hits the ratchet, releases the shaft lock, and the shaft rotates within 90° under the action of the spring. The rotating shaft drives the cam, and the cam pushes the valve core / piston of the overspeed valve 22 to move, realizing the oil circuit switching.

[0058] The overspeed valve 22 has a P port, an A port and a T port. The P port of the overspeed valve 22 is used for oil supply, the T port of the overspeed valve 22 is used for oil return, and the A port of the overspeed valve 22 is used for outputting or inputting pressurized oil.

[0059] Specifically, under the action of the overspeed detector 21, the P port and B port of the overspeed valve 22 are connected, or the T port and B port of the overspeed valve 22 are connected.

[0060] The specific types of the overspeed detector 21 and the overspeed valve 22 can be set according to actual needs, and there are no restrictions on them.

[0061] In some embodiments, the system further includes a monitoring module, the signal input terminal of which is connected to the signal output terminal of the mechanical hydraulic overspeed protection device 2, and the mechanical hydraulic overspeed protection device 2 is used to send a warning signal to the monitoring module when the actual rotation speed of the rotating shaft in the unit exceeds the preset speed.

[0062] Understandably, since the signal input terminal of the monitoring module is connected to the signal output terminal of the mechanical hydraulic overspeed protection device 2, when the actual speed of the rotating shaft in the unit exceeds the preset speed, the mechanical hydraulic overspeed protection device 2 can send an early warning signal to the monitoring module, thereby facilitating the monitoring and maintenance of the system.

[0063] It should be noted that the monitoring module is used to monitor the system status. The specific type of monitoring module can be set according to actual needs and there are no restrictions on it. For example, the monitoring module can be the monitoring center of a hydropower station.

[0064] like Figure 1 As shown, in some embodiments, the system further includes a pressure detection unit 8, the oil input terminal of which is connected to the oil input terminal of the pressure regulating valve group 4 and the oil input terminal of the proportional valve group 3 respectively, and the pressure detection unit 8 is used to detect the pressure of the pressure oil.

[0065] Understandably, since the oil input terminal of the pressure detection unit 8 is connected to the oil input terminal of the pressure regulating valve group 4 and the oil input terminal of the proportional valve group 3 respectively, the pressure detection unit 8 can detect the pressure of the pressure oil, thereby realizing pressure monitoring of the oil input terminals of the pressure regulating valve group 4 and the proportional valve group 3, and ensuring the stable operation of the system.

[0066] It should be noted that the pressure detection unit 8 is used to detect the pressure of the pressure oil. The specific type of the pressure detection unit 8 can be set according to actual needs, and there are no restrictions on it.

[0067] In the description of this disclosure, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance. Furthermore, in the description of this disclosure, unless otherwise stated, "a plurality of" means two or more.

[0068] Any process or method description in the flowchart or otherwise herein can be understood as representing a module, segment, or portion of code comprising one or more executable instructions for implementing a particular logical function or process, and the scope of preferred embodiments of this disclosure includes additional implementations in which functions may be performed not in the order shown or discussed, including substantially simultaneously or in reverse order depending on the function involved, as will be understood by those skilled in the art to which embodiments of this disclosure pertain.

[0069] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this disclosure. 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.

[0070] Although embodiments of the present disclosure have been shown and described above, it is to be understood that the above embodiments are exemplary and should not be construed as limiting the present disclosure. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present disclosure.

Claims

1. An overspeed protection system for hydropower station units, characterized in that, include: Hydraulic valve assembly and mechanical hydraulic overspeed protection device; The hydraulic control valve group's oil input end is connected to the proportional valve group's oil output end, and the hydraulic control valve group's oil output end is connected to the pressure distribution valve group's control input end. The proportional valve group is used to control the oil pressure at the pressure distribution valve group's control input end, so that the pressure distribution valve group controls the opening degree of the guide vanes in the unit. The power input end of the mechanical hydraulic overspeed protection device is connected to the power output end of the rotating shaft in the unit, and pressurized oil is introduced into the oil input end of the mechanical hydraulic overspeed protection device. The oil output end of the mechanical hydraulic overspeed protection device is connected to the control input end of the hydraulic control valve group. The mechanical hydraulic overspeed protection device is used to stop supplying pressurized oil to the control input terminal of the hydraulic control valve group when the actual rotation speed of the rotating shaft in the unit exceeds the preset speed, so that the hydraulic control valve group cuts off the passage between the oil output terminal of the proportional valve group and the control input terminal of the pressure distribution valve group.

2. The hydropower station unit overspeed protection system according to claim 1, characterized in that, The hydraulic control valve assembly includes: The hydraulic directional valve has its P port connected to the oil output terminal of the proportional valve group, its T port connected to the oil tank, its B port connected to the control input terminal of the pressure regulating valve group, and its X port connected to the oil output terminal of the mechanical hydraulic overspeed protection device. The hydraulically controlled directional valve is used to open ports P and B when port X receives pressurized oil supplied by the mechanical hydraulic overspeed protection device, and to open ports T and B when port X does not receive pressurized oil supplied by the mechanical hydraulic overspeed protection device.

3. The hydropower station unit overspeed protection system according to claim 2, characterized in that, The proportional valve assembly includes: First servo proportional valve and second servo proportional valve. Wherein, the P port of the first servo proportional valve is supplied with pressurized oil, and the T port of the first servo proportional valve is connected to the oil tank, and the A port of the first servo proportional valve is connected to the P port of the hydraulic control directional valve. The P port of the second servo proportional valve is supplied with pressurized oil, and the T port of the second servo proportional valve is connected to the oil tank. The A port of the second servo proportional valve is connected to the T port of the hydraulic directional valve.

4. The hydropower station unit overspeed protection system according to claim 3, characterized in that, The proportional valve assembly also includes: The first electromagnetic directional valve is disposed between the hydraulic directional valve and the proportional valve group, and the P port of the first electromagnetic directional valve is connected to the A port of the first servo proportional valve, the T port of the first electromagnetic directional valve is connected to the A port of the second servo proportional valve, and the A port of the first electromagnetic directional valve is connected to the P port of the hydraulic directional valve. Wherein, the first electromagnetic reversing valve is used to connect the P port and A port of the first electromagnetic reversing valve, or to connect the T port and A port of the first electromagnetic reversing valve.

5. The hydropower station unit overspeed protection system according to claim 4, characterized in that, The system also includes: The second electromagnetic directional valve is disposed between the hydraulic directional valve and the first electromagnetic directional valve, and the P port of the second electromagnetic directional valve is connected to the A port of the first electromagnetic directional valve. The T port of the second electromagnetic directional valve is connected to the oil tank, and the A port of the second electromagnetic directional valve is connected to the P port of the hydraulic directional valve. The second electromagnetic reversing valve is used to connect the P port and A port of the second electromagnetic reversing valve, or to connect the T port and A port of the second electromagnetic reversing valve.

6. The hydropower station unit overspeed protection system according to claim 5, characterized in that, The system also includes: The third electromagnetic directional valve is disposed between the hydraulic directional valve and the second electromagnetic directional valve, and the P port of the third electromagnetic directional valve is connected to the A port of the second electromagnetic directional valve. The T port of the third electromagnetic directional valve is connected to the oil tank, and the A port of the third electromagnetic directional valve is connected to the P port of the hydraulic directional valve. The third electromagnetic reversing valve is used to connect the P port and A port of the third electromagnetic reversing valve, or to connect the T port and A port of the third electromagnetic reversing valve.

7. The hydropower station unit overspeed protection system according to claim 6, characterized in that, The system also includes: The hydraulic integrated block contains the pressure distribution valve group, and the hydraulic control directional valve, the first solenoid directional valve, the second solenoid directional valve, the third solenoid directional valve, the first servo proportional valve, and the second servo proportional valve are sequentially and alternately arranged on the hydraulic integrated block.

8. The hydropower station unit overspeed protection system according to claim 2, characterized in that, The mechanical hydraulic overspeed protection device includes: Overspeed detector and overspeed valve; The power input terminal of the overspeed detector is connected to the power output terminal of the rotating shaft in the unit, and the power output terminal of the overspeed detector is connected to the power input terminal of the overspeed valve. The overspeed valve's P port is supplied with pressurized oil, and the overspeed valve's A port is connected to the hydraulic control valve assembly's X port. The overspeed valve's T port is connected to the oil tank. The overspeed valve is used to supply pressurized oil to the X port of the hydraulic control valve group when the actual rotation speed of the rotating shaft in the unit does not exceed the preset speed, so as to open the P port and B port of the hydraulic control directional valve. In addition, when the actual rotational speed of the rotating shaft in the unit exceeds the preset speed, the supply of pressurized oil to the X port of the hydraulic control valve group is stopped, so that the T port and B port of the hydraulic control directional valve are opened.

9. The hydropower station unit overspeed protection system according to claim 1, characterized in that, The system also includes: The monitoring module has its signal input terminal connected to the signal output terminal of the mechanical hydraulic overspeed protection device, and the mechanical hydraulic overspeed protection device is used to send a warning signal to the monitoring module when the actual rotation speed of the rotating shaft in the unit exceeds the preset speed.

10. The hydropower station unit overspeed protection system according to claim 1, characterized in that, The system also includes: The pressure detection unit is connected to the oil input terminals of the pressure regulating valve group and the proportional valve group, respectively, and is used to detect the pressure of the pressure oil.

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