A valve control system for a hydroelectric plant

Abstract

This invention discloses a valve control system for a hydropower plant. The valve is a cylindrical valve, with multiple sets of hydraulic actuators connected to its upper end. The hydraulic actuators are opened and closed and their stroke is determined via a PLC control cabinet. The piston rod of the hydraulic actuator is connected to the upper end of the cylindrical valve body. The hydraulic actuator is equipped with a displacement sensor, and a new sensor is installed at the upper end of the cylindrical valve body. Both the displacement sensor and the new sensor are connected to the PLC control cabinet. The displacement sensor and the new sensor jointly monitor whether the vertical stroke of the cylindrical valve body is synchronized. When they are not synchronized, it is determined that the stroke of one or more hydraulic actuators is incorrect and feedback is sent to the PLC control cabinet. The PLC control cabinet determines that the corresponding hydraulic actuator is abnormal and the cylinder is tilted. This control system is equipped with multiple sets of different types of sensors to avoid false signal triggering, which could lead to unnecessary losses in the unit operation.

Description

Technical Field

[0001] This invention relates to a valve control system for a hydropower plant. Background Technology

[0002] The cylindrical valve is a flow-through component located between the movable guide vanes and the fixed guide vanes of the turbine generator set. It is only in the fully open or fully closed position and does not regulate flow. The cylindrical valve should be able to safely and reliably close under any operating condition of the turbine. In existing technology, the servo piston rod and the cylindrical valve body are usually connected by a nut. However, if the connecting nut loosens, it can cause the valve body to tilt or even jam, seriously affecting the success rate of unit start-up and shutdown and safe and stable operation. Secondly, the sensors are all single-point detectors, directly connected to the PLC control system, lacking redundant detection methods, making signals prone to false transmissions and reducing reliability. Summary of the Invention

[0003] In view of the shortcomings of the prior art, this application provides a valve control system for a hydropower plant. The control system improves the connection between the piston rod of the servo motor and the upper end of the cylindrical valve body to avoid the problem of the cylinder body tilting due to loose nuts. It also sets up multiple sets of different types of sensors to avoid false signal triggering, which would cause unnecessary losses in the operation of the unit.

[0004] To achieve the above objectives, this application provides a valve control system for a hydropower plant. The valve is a cylindrical valve, and multiple sets of hydraulic actuators are connected to the upper end of the cylindrical valve. The hydraulic actuators are controlled to open and close and to determine their stroke by a PLC control cabinet. The piston rod of each hydraulic actuator is connected to the upper end of the cylindrical valve body. Each hydraulic actuator is equipped with a displacement sensor, and a new sensor is installed at the upper end of the cylindrical valve body. Both the displacement sensor and the new sensor are connected to the PLC control cabinet. The displacement sensor and the new sensor jointly monitor whether the vertical stroke of the cylindrical valve body is synchronized. When they are not synchronized, it is determined that the stroke of one or more hydraulic actuators is incorrect and feedback is sent to the PLC control cabinet. The PLC control cabinet then determines that there is an abnormality in the hydraulic actuator and that the cylindrical valve body is tilted.

[0005] Furthermore, the piston rod end of the hydraulic relay is provided with a connecting joint, which is rectangular in shape. The side wall of the connecting joint is provided with a first tooth pattern. The connecting joint is provided with two intersecting through channels in the transverse direction. The through channels are used for connecting the reinforcing connector at the upper end of the cylindrical valve body.

[0006] Furthermore, the reinforcing connector includes a mounting groove on the upper end face of the cylindrical valve body corresponding to the connecting joint. The mounting groove sidewalls are provided with slides on both sides, and the slides are staggered vertically. The slide outlet end face is provided with a second tooth that meshes with the first tooth. The upper end face of the slide is provided with a waist-shaped groove that communicates with the outside. An insert block is slidably connected inside the slide. The insert block is provided with an extension block corresponding to the waist-shaped groove. Adjacent extension blocks are all equipped with a driving component. The driving component is used to drive the insert block to extend along the slide and insert into the corresponding through channel.

[0007] Furthermore, the driving component includes a V-shaped hinge rod, the common hinge end of which is connected to a telescopic hydraulic rod. The telescopic hydraulic rod extends and retracts to drive the V-shaped hinge rod to move the insert block.

[0008] Furthermore, the driving component includes a rack connected to an extension block, with the bottom of the rack slidably connected to the upper end face of the cylinder. The rack is equipped with a meshing gear, and the meshing gear is equipped with an anti-rotation insert rod. The insertion block is moved by rotating the meshing gear.

[0009] Furthermore, the new sensing element includes multiple monitoring units, each of which includes a housing and a ball disposed within the housing. The housing is capsule-shaped, and a rolling cavity is formed inside the housing. The rolling cavity is equipped with a sensing plate, and the sensing plate has micro-protrusions along its length. The ball has a built-in position sensor. The position of the ball within the rolling cavity is displayed on the PLC control cabinet screen to form a visual representation. The tilt direction of the cylindrical valve is determined by comprehensively analyzing the movement of multiple sets of balls.

[0010] Furthermore, the new sensing element is embedded in the upper end face of the cylindrical valve body.

[0011] Furthermore, the displacement sensor includes multiple sets of laser displacement sensors. The laser emitting end of the sensor is positioned facing the end of the piston rod of the hydraulic servo drive. The end of the piston rod is provided with a reflective target surface corresponding to the laser emitting end. The signal output end of the laser displacement sensor is connected to the PLC control cabinet to collect the stroke data of the corresponding hydraulic servo drive piston rod in real time, and the acquisition frequency is consistent with the ball position acquisition frequency of the new sensor.

[0012] Furthermore, both the displacement sensor and the new sensor are connected to the PLC control cabinet for signal transmission and monitoring data transmission. The PLC control cabinet has a built-in data processing unit that can receive and comprehensively analyze the hydraulic relay stroke data monitored by the displacement sensor and the cylindrical valve body status data monitored by the new sensor, so as to make a comprehensive judgment on the operating status of the hydraulic relay and the working status of the cylindrical valve.

[0013] Beneficial effects: This application avoids the problem of easy loosening of existing traditional nut connections by setting up a rectangular toothed connector and a reinforced connector. The connector sidewall has a first tooth, which increases the friction of the connection surface. The staggered through channels and the plug form a bidirectional rigid plug connection. With the locking of the drive component, it solves the problem of cylinder tilting and jamming caused by loose connection. It also greatly reduces the difficulty and cost of operation and maintenance. The plug-type rigid connection structure eliminates the traditional nut anti-loosening maintenance process and eliminates the need for regular nut tightening.

[0014] 2. This application also achieves mutual verification of drive end stroke monitoring and execution end attitude monitoring through dual-source synchronous monitoring of displacement sensing element and new sensing element. The PLC control cabinet locates abnormal relay device by comparing data, avoiding invalid shutdown due to false alarm of single point sensor and improving reliability. Among them, the visualization monitoring function of new sensing element intuitively presents the tilt direction on the PLC display screen. Combined with displacement sensing element, it can lock the position of abnormal relay device or determine whether there is a fault type of foreign object obstruction. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the control system; Figure 2 A top view of the cylindrical valve of the first type of drive component; Figure 3 A schematic diagram of the slide and the insert block; Figure 4 This is a schematic diagram of the connection joint and mounting groove; Figure 5 Schematic diagram of the new sensor; Figure 6 This is a schematic diagram of the second type of drive component; Figure 7 for Figure 6 A schematic diagram of the local method in part A; Figure 8 A schematic diagram of the stop-rotation plug and the irregular-shaped socket.

[0016] Reference numerals: 1. Cylindrical valve; 2. Hydraulic relay; 2-1. Piston rod; 3. PLC control cabinet; 4. Displacement sensor; 4-1. Laser displacement sensor; 4-2. Reflective target surface; 5. New sensor; 5-1. Housing; 5-2. Ball; 5-3. Rolling chamber; 5-4. Sensing plate; 5-5. Micro-protrusion; 6. Connecting joint; 6-1. First tooth; 6-2. Through channel; 7. Reinforcing connection Components; 7-1, Mounting slot; 7-2, Second toothed groove; 7-3, Waist-shaped groove; 7-4, Insert block; 7-5, Extension block; 7-6, Slide rail; 7-7, Drive component; 8, Fixed guide vane; 9, Movable guide vane; 10, Top cover; 11, Seat ring; 12, V-shaped hinge rod; 13, Telescopic hydraulic rod; 14, Rack; 15, Meshing gear; 16, Irregularly shaped insert; 17, Anti-rotation insert rod; 17-1, Irregularly shaped plug. Detailed Implementation

[0017] To further illustrate the technical means and effects of the present invention in achieving its intended purpose, the following detailed description of the specific implementation methods, structures, features, and effects of the present invention, in conjunction with the accompanying drawings and preferred embodiments, is provided below.

[0018] For reference Figures 1-8As shown, this application provides a valve control system for a hydropower plant. The valve is a cylindrical valve 1, which is installed between a fixed guide vane 8 and a movable guide vane 9. When it rises, it retracts into the cavity formed between the top cover 10 and the seat ring 11 (this is prior art and will not be described in detail here). Multiple sets of hydraulic relays 2 are connected to the upper end of the cylindrical valve 1. The hydraulic relays 2 are opened and closed and their stroke is determined by a PLC control cabinet 3. The hydraulic relays 2 are prior art and will not be described in detail here. One of the main problems this application aims to solve is the problem of easy loosening of the connection between the hydraulic relays 2 and the cylindrical valve 1. The piston rod 2-1 of the hydraulic relay 2 is connected to the upper end of the valve body of the cylindrical valve 1. The end of the piston rod 2-1 of the hydraulic relay 2 is provided with a connecting joint 6, and the end is hinged to the connecting joint 6 with spherical steel to accommodate slight deformation. The connecting joint 6 is rectangular in shape. The side wall of the connecting joint 6 is provided with a first tooth 6-1. The connecting joint 6 is provided with two intersecting through channels 6-2 in the transverse direction. The through channels 6-2 are used to connect to the reinforcing connecting piece 7 at the upper end of the cylindrical valve 1. The reinforcing connector 7 includes a mounting groove 7-1 on the upper end face of the cylindrical valve 1 corresponding to the connecting joint 6. The number of hydraulic relays 2 is determined according to the size of the cylindrical valve 1. Taking a small cylindrical valve 1 as an example, the preferred number of hydraulic relays 2 is 6 sets. The mounting groove 7-1 is also set with 6 relays. The side walls of the mounting groove 7-1 are provided with slides 7-6 on both sides. The slides 7-6 are arranged in an alternating pattern. The outlet end face of the slide 7-6 is provided with a second tooth 7-2 that meshes with the first tooth 6-1. The upper end face of the slide 7-6 is provided with a waist-shaped groove 7-3 that communicates with the outside. A plug 7-4 is slidably connected inside the slide 7-6. The plug 7-4 is provided with an extension block 7-5 corresponding to the waist-shaped groove 7-3. Adjacent extension blocks 7-5 are all equipped with a driving member 7-7. The driving member 7-7 is used to drive the plug 7-4 to extend along the slide and insert into the corresponding through channel 6-2. This application addresses the issue of loosening by engaging the first tooth 6-1 on the connecting joint 6 with the second tooth 7-2 on the mounting groove 7-1, preventing vertical loosening between the connecting joint 6 and the mounting groove 7-1. Furthermore, the transverse insertion of the through-channel 6-2 and the insert block 7-4 prevents the connecting head from detaching from the mounting groove 7-1 in the radial direction of the cylindrical valve 1. This solves the loosening problem from two directions, avoiding the use of nuts, which can loosen due to vibration within the cylinder, or the need for additional anti-loosening components or regular maintenance and tightening. To reduce wear between the connecting joint 6 and the mounting groove 7-1 due to vibration, existing anti-wear measures such as padding or protective layers can be used, which are prior art and will not be elaborated upon here.

[0019] For reference Figure 2 , 3As shown, the first type of driving component 7-7 includes a V-shaped hinge rod 12. A telescopic hydraulic rod 13 is connected to the common hinge end of the V-shaped hinge rod 12. The telescopic hydraulic rod 13 is fixed to the upper end face of the cylindrical valve 1, preferably by welding. The telescopic hydraulic rod 13 activates the telescopic drive, pushing the insert block 7-4 to move, achieving insertion. After insertion, the telescopic hydraulic rod 13 locks in place, completing the connection between the relay and the cylindrical valve 1. Alternatively, another method can be used, as shown in the example... Figure 6-8 As shown, another type of drive component 7-7 includes a rack 14, which is connected to the extension block 7-5. The bottom of the rack 14 is slidably connected to the upper end face of the cylinder. The rack 14 is equipped with a meshing gear 15. Adjacent racks 14 are staggered vertically to avoid mutual interference. The meshing gear 15 is equipped with an anti-rotation insert 17. Rotation of the meshing gear 15 moves the insert block 7-4. The upper end of the cylinder has a corresponding irregularly shaped insertion port 16 on the insert. The end of the anti-rotation insert 17 has a corresponding irregularly shaped insert 17-1. The side wall of the anti-rotation insert 17 and the meshing gear 15 have vertical blocks and vertical guide grooves. Rotation of the anti-rotation insert 17 drives the meshing gear 15 to rotate. When the insert block 7-4 is inserted into the through channel 6-2, the anti-rotation insert 17 moves down, and the irregularly shaped insert 17-1 engages with the irregularly shaped insertion port 16 to prevent rotation. The top view shape of the irregularly shaped insertion port 16 and the irregularly shaped insert 17-1 can be triangular, square, hexagonal, etc., preferably multi-shaped. A rubber layer can be provided around the irregularly shaped insert 17-1 to ensure a firm connection and reduce shaking caused by cylinder vibration. The two drive components 7-7 mentioned above can be selected according to actual conditions, both capable of connecting the relay and the cylindrical valve 1.

[0020] For reference Figure 1 As shown, this application also provides the following solution to address the problem of false triggering in existing single-point sensor monitoring: multiple different sensors are used to achieve multi-point monitoring and multiple monitoring methods, comprehensively judging the status of hydraulic servo 2 and cylindrical valve 1. Specifically, the hydraulic servo 2 is equipped with a displacement sensor 4, and the upper end of the cylindrical valve 1 is equipped with a new sensor 5. Both the displacement sensor 4 and the new sensor 5 are connected to the PLC control cabinet 3. The displacement sensor 4 and the new sensor 5 monitor whether the vertical stroke of the cylindrical valve 1 is synchronized. When they are not synchronized, it is comprehensively determined that the stroke of one or more hydraulic servo 2 is incorrect and feedback is sent to the PLC control cabinet 3. The PLC control cabinet 3 judges that the hydraulic servo 2 is abnormal and the cylinder is tilted.

[0021] Reference Figure 2 , Figure 5The new sensor 5 shown includes multiple monitoring units, preferably six. Each monitoring unit includes a housing 5-1 and a ball 5-2 disposed within the housing 5-1. The housing 5-1 is capsule-shaped and has a sealed structure to prevent water and dust from entering and affecting its internal operation. A rolling cavity 5-3 is formed inside the housing 5-1, and the rolling cavity 5-3 is equipped with a sensing plate 5-4. The sensing plate 5-4 has micro-protrusions 5-5 along its length, and tiny limiting grooves are formed between adjacent micro-protrusions 5-5. The diameter of the ball 5-2 is adapted to the limiting groove. Under normal conditions, the ball 5-2 is engaged in the limiting groove. Small bounces or slippage caused by vibration cannot make the ball 5-2 cross the height of the micro-protrusions 5-5. Only the continuous driving force generated by the tilting of the cylinder can push the ball 5-2 to roll along the limiting groove, thereby limiting the erroneous movement of the ball 5-2 caused by vibration. To further reduce the impact of vibration, a rubber damping pad made of highly elastic rubber can be installed between the shell 5-1 and the cylinder mounting surface to weaken the transmission of cylinder vibration into the shell 5-1. Alternatively, a high-viscosity silicone oil can be filled into the cavity as a damping medium to effectively absorb the high-frequency, small-amplitude vibration energy generated during operation. The rolling ball 5-2 is made of tungsten steel, which has a high density and hard texture. It is suspended in the damping medium. Only when the cylinder generates a continuous and tendency to tilt greater than the damping medium will the rolling ball 5-2 move. The instantaneous impact force from the vibration will be quickly attenuated by the damping medium and will not be able to push the ball to move effectively. Both of the above methods can achieve cylinder tilt monitoring. This application preferably adopts a micro-protrusion strip 5-5 structure. The new sensor 5 senses the tilt of the cylinder by changing the position of the ball 5-2. After the system starts, the cylindrical valve 1 is in a vertical position. At this time, the ball 5-2 in each monitoring unit is in the middle position of the sensing plate 5-4 under the action of gravity. The position sensor collects the initial position coordinates and transmits them to the PLC control cabinet 3 as the reference zero point for subsequent tilt judgment. Then, when the cylinder of the cylindrical valve 1 tilts, the ball 5-2 rolls along the tilt direction under the combined action of gravity and the tilting force of the cylinder. The larger the tilt angle, the greater the rolling distance. The position sensor collects the position coordinates of the ball 5-2 in real time and records the offset direction relative to the reference zero point. The position sensor built into the ball 5-2 converts the collected three-dimensional position coordinates into an electrical signal, filters and amplifies it, and sends it to the PLC control cabinet 3. When the six monitoring units collect tilt data from different positions of the cylinder, the PLC control cabinet 3 receives the position signals of all units. For example, if two sets of monitoring units arranged opposite each other show that the ball 5-2 is offset in the same direction, and the ball 5-2 of the other monitoring units does not change position, the tilt direction of the cylinder can be determined. To further calculate the tilt angle, the PLC control cabinet 3 calculates the offset using the position coordinates of the ball 5-2, and then obtains the accurate tilt angle value through a preset angle conversion relationship. This is existing technology and will not be elaborated on here.

[0022] For reference Figure 1As shown, the displacement sensing element 4 includes multiple sets of laser displacement sensors 4-1. The laser emitting end of the sensor is positioned facing the end of the piston rod 2-1 of the hydraulic servo drive 2. A reflective target surface 4-2 is provided at the end of the piston rod 2-1 corresponding to the laser emitting end. The signal output end of the laser displacement sensor 4-1 is connected to the PLC control cabinet 3 to collect the stroke data of the piston rod 2-1 of the hydraulic servo drive 2 in real time, and the acquisition frequency is consistent with the position acquisition frequency of the rolling ball 5-2 of the new sensing element 5. Both the displacement sensing element 4 and the new sensing element 5 are connected to the PLC control cabinet 3 for signal transmission and monitoring data. The PLC control cabinet 3 has a built-in data processing unit that can receive and comprehensively analyze the stroke data of the hydraulic servo drive 2 monitored by the displacement sensing element 4 and the cylinder state data of the cylindrical valve 1 monitored by the new sensing element 5 to make a comprehensive judgment on the operating status of the hydraulic servo drive 2 and the working status of the cylindrical valve 1. The specific workflow is as follows: The stroke data of the piston rod 2-1 of the hydraulic relay 2 is collected via displacement sensor 4, and the status data of the cylinder body of the cylindrical valve 1 is collected via new sensor 5. The stroke data and cylinder status data are synchronously transmitted to the PCL controller, where the data synchronization calibration unit completes time point alignment. The PCL control cabinet calls pre-stored normal operating condition reference parameters, including stroke deviation thresholds and cylinder tilt thresholds, to calculate the deviation between the average vertical stroke of each group of piston rods 2-1 and the cylinder, and simultaneously extracts the cylinder tilt direction. When a stroke deviation exceeds the limit and the tilt direction points towards that group of relays, the PLC determines it is abnormal and compensates for the deviation by adjusting the hydraulic system pressure. When the stroke is synchronized but the cylinder tilts, it is determined to be obstructed by a foreign object, and a warning signal is issued.

Claims

1. A valve control system for a hydropower plant, wherein the valve is a cylindrical valve, and multiple sets of hydraulic relays are connected to the upper end of the cylindrical valve. The hydraulic relays are controlled to open and close and to determine their stroke by a PLC control cabinet. The system is characterized by: The piston rod of the hydraulic servo is connected to the upper end of the cylindrical valve body. The hydraulic servo is equipped with a displacement sensor, and the upper end of the cylindrical valve body is equipped with a new sensor. Both the displacement sensor and the new sensor are connected to the PLC control cabinet. The displacement sensor and the new sensor jointly monitor whether the vertical stroke of the cylindrical valve body is synchronized. When they are not synchronized, it is determined that the stroke of one or more hydraulic servos is incorrect and feedback is sent to the PLC control cabinet. The PLC control cabinet determines that there is an abnormality in the hydraulic servo and that the cylinder is tilted.

2. The hydropower plant valve control system according to claim 1, characterized in that: The piston rod end of the hydraulic relay is provided with a connecting joint. The connecting joint is rectangular in shape and has a first tooth pattern on its side wall. The connecting joint has two intersecting through channels in the transverse direction. The through channels are used to connect to the reinforcing connector at the upper end of the cylindrical valve body.

3. The hydropower plant valve control system according to claim 2, characterized in that: The reinforcing connector includes a cylindrical valve body with mounting grooves on the upper end face of the corresponding connecting joint. The mounting grooves have horizontal slides on both sides of their side walls, and the slides are staggered vertically. The slide outlet end face has a second tooth that meshes with the first tooth. The upper end face of the slide has a waist-shaped groove that communicates with the outside. A plug is slidably connected inside the slide. The plug has an extension block corresponding to the waist-shaped groove. The extension block is equipped with a driving component. The driving component is used to drive the plug to extend along the slide and insert into the corresponding through channel.

4. The hydropower plant valve control system according to claim 3, characterized in that: The driving component includes a V-shaped hinge rod, with both ends of the V-shaped hinge rod connected to adjacent extension blocks. The common hinge end of the V-shaped hinge rod is connected to a telescopic hydraulic rod, which drives the V-shaped hinge rod to move the insertion block by extending and retracting the telescopic hydraulic rod.

5. The hydropower plant valve control system according to claim 3, characterized in that: The driving component includes a rack connected to an extension block. The bottom of the rack is slidably connected to the upper end face of the cylinder. The rack is equipped with a meshing gear, and the meshing gear is equipped with an anti-rotation rod. The movement of the insertion block is achieved by rotating the meshing gear.

6. The hydropower plant valve control system according to claim 3 or 4, characterized in that: The new sensing element includes multiple monitoring units. Each monitoring unit includes a housing and a ball set inside the housing. The housing is capsule-shaped and has a rolling cavity inside. The rolling cavity is equipped with a sensing plate. The sensing plate has micro-protrusions along its length. The ball has a built-in position sensor. The position of the ball in the rolling cavity is displayed on the PLC control cabinet screen to form a visual representation. The tilt direction of the cylindrical valve is determined by comprehensively judging the movement of multiple sets of balls.

7. The hydropower plant valve control system according to claim 6, characterized in that: The new sensor is embedded in the upper end face of the cylindrical valve body.

8. The hydropower plant valve control system according to claim 7, characterized in that: The displacement sensor includes multiple sets of laser displacement sensors. The laser emitting end of the sensor is set towards the end of the piston rod of the hydraulic servo drive. The end of the piston rod is provided with a reflective target surface corresponding to the laser emitting end. The signal output end of the laser displacement sensor is connected to the PLC control cabinet to collect the stroke data of the corresponding hydraulic servo drive piston rod in real time. The acquisition frequency is consistent with the ball position acquisition frequency of the new sensor.

9. The hydropower plant valve control system according to claim 8, characterized in that: Both the displacement sensor and the new sensor are connected to the PLC control cabinet and transmit monitoring data. The PLC control cabinet has a built-in data processing unit that can receive and comprehensively analyze the hydraulic relay stroke data monitored by the displacement sensor and the cylindrical valve body status data monitored by the new sensor, so as to make a comprehensive judgment on the operating status of the hydraulic relay and the working status of the cylindrical valve.

Images