Device for controlling a cylinder gate of a hydroelectric power plant and hydroelectric power plant with such a device

Abstract

Device (1) for controlling a cylinder gate (2) of a water power plant comprising a cylinder gate (2), at least six hydraulic cylinders (3.1, 3.2, 3.3, 4.1, 4.2, 4.3, 4.4, 4.5, 4.6) connected to the cylinder gate (2), each with two chambers, at least one pressure source (6), at least one valve (8) and a tank (7), wherein at least three of the hydraulic cylinders (3.1, 3.2, 3.3) form a drive group (3) and the remaining hydraulic cylinders (4.1, 4.2, 4.3, 4.4, 4.5, 4.6) form a guide group (4), which is hydraulically separated from the drive group (3), and wherein the hydraulic cylinders (4.1, 4.2, 4.3, 4.4, 4.5, 4.6) of the guide group (4) form at least a series ring circuit.

Description

[0001] The invention relates to a device for controlling a ring gate. Ring gates are used in hydroelectric power plants to stop the flow of water through a hydraulic machine of the power plant.

[0002] A cylinder gate is used in a hydraulic machine that includes a guide vane assembly (i.e., the hydraulic machine is usually of the Francis type) and is located within the guide vane assembly. A cylinder gate comprises a cylindrical ring that moves axially to open and close the gate. The ring's diameter can be very large, as it usually encircles the movable guide vanes of the hydraulic machine when closed. Hydraulic cylinders are used to move the ring. There are at least three hydraulic cylinders, though six are very common. Because the ratio of the ring's axial length to its diameter is unfavorable, the ring tends to tilt during axial movement. Therefore, synchronous operation of the hydraulic cylinders must be ensured for reliable operation.In normal operation, tilting is often ensured by active synchronization control via the controller of the hydraulic machine.

[0003] A cylinder contactor is also a safety element that must be able to shut down the hydraulic machine in the event of a fault. If the hydraulic machine's controller fails, it would no longer be possible to reliably prevent the cylinder contactor from jamming. Therefore, various proposals for synchronizing the hydraulic cylinders have been developed based on the prior art, ensuring that the hydraulic cylinders continue to move in unison even if the hydraulic controller fails.

[0004] For example, US 2013 / 0098237 A1 discloses a device for controlling a cylinder contactor. In this device, the hydraulic cylinders form at least two separate groups, each with at least two hydraulic cylinders. The hydraulic cylinders within a group are connected to each other by means of synchronization elements. These synchronization elements can be hydraulic lines. In this case, the hydraulic cylinders connected in this way must be of different designs. A similar device is also disclosed in US 2020 / 0386247 A1. The synchronization elements in US 2013 / 0098237 A1 can also be hydraulic flow dividers. In this case, the hydraulic cylinders connected in this way can be of the same design.

[0005] US patent number 4,434,964 discloses a device in which the linear motion of hydraulic cylinders is converted into rotation. The rotating elements of the hydraulic cylinders are connected to each other via chain drives to ensure synchronization.

[0006] Further generic devices are disclosed in documents US 2014 / 0 326 910 A1 and WO 2013 / 175 969 A1.

[0007] The object of the invention is to provide an alternative device for controlling a cylinder contactor, which ensures synchronous control in the event of a failure of the regulator of the hydraulic machine.

[0008] The invention will be explained below with the aid of figures. The figures show, in detail: Fig. 1: Device according to the invention in a first embodiment Fig. 2: Hydraulics of the first embodiment Fig. 3: Device according to the invention in a second embodiment (drive cylinder not shown) Fig. 4: Guide unit of the second embodiment Fig. 5: Device according to the invention in a third embodiment (drive cylinder not shown) Fig. 6: Guide unit of the third embodiment, variant 1 Fig. 7: Guide unit of the third embodiment, variant 2

[0009] The inventor was guided by the idea of ​​dividing the hydraulic cylinders that act on the cylinder gate into two completely separate groups, one of which performs a purely guiding function and the other a purely driving function.

[0010] Fig. Figure 1 shows a device according to the invention for controlling a cylinder contactor in a first embodiment. The device is designated 1 and comprises a cylinder contactor, designated 2, a plurality of hydraulic cylinders mechanically connected to the cylinder contactor, and a control unit, designated 5. The Fig. The embodiment shown in Figure 1 comprises a total of six hydraulic cylinders, which form two groups. A first group comprises three hydraulic cylinders, designated 3.1, 3.2, and 3.3. A second group comprises the remaining three hydraulic cylinders, designated 4.1, 4.2, and 4.3. The first group is the so-called drive group, since the associated hydraulic cylinders 3.1, 3.2, and 3.3 actively transmit forces to the ring gate 2, which cause it to raise and lower, i.e., to open and close. The hydraulic cylinders of the drive group are therefore also referred to as drive cylinders. The second group is the so-called guide group, since the associated hydraulic cylinders 4.1, 4.2, and 4.3 act only passively, exerting significant counterforces when the ring gate 2 tilts, thus preventing it from jamming.The hydraulic cylinders of the guide group are therefore also referred to as guide cylinders. The control unit 5 is designed to control the opening and closing of the ring gate 2. For this purpose, the control unit 5 interacts solely with the drive cylinders 3.1, 3.2, and 3.3, and not with the guide cylinders 4.1, 4.2, and 4.3. It should be noted that the representation of the hydraulic cylinders in [reference missing]... Fig. Figure 1 is purely schematic and does not intend to provide any information about the actual design of the hydraulic cylinders. This applies in particular to guide cylinders 4.1, 4.2, and 4.3.

[0011] It is advantageous if the hydraulic cylinders are evenly distributed around the circumference and act on ring gate 2, as shown in Fig. Figure 1 shows that slight deviations from a uniform distribution are negligible. However, larger deviations lead to an increasing loss of performance and should be avoided if possible. The hydraulic cylinders of the two groups are arranged alternately, i.e., in the circumferential direction, a guide cylinder follows a drive cylinder and vice versa. However, embodiments are also conceivable in which more than one drive cylinder follows a guide cylinder. For example, a variant of the one shown in Fig. In the embodiment shown in 1, a total of 6 drive cylinders and 3 guide cylinders are provided, wherein two drive cylinders are always arranged between two adjacent guide cylinders in the circumferential direction.

[0012] Fig. Figure 2 shows the hydraulic connection of the hydraulic cylinders of the embodiment from Fig. 1. The drive unit is shown on the left and labeled 3. The guide unit is shown on the right and labeled 4. There is no hydraulic connection between the two units.

[0013] The drive group 3 comprises, in addition to the drive cylinders 3.1, 3.2 and 3.3, a pressure source, designated 6, a tank, designated 7 and a directional control valve, designated 8. The pressure source 6 can be a pump or a storage tank, as shown in Fig. 2 indicated. The drive cylinders 3.1, 3.2 and 3.3 can be designed as differential cylinders, as shown in Fig. 2 indicated. In this case, pressurizing the piston-side chamber of the drive cylinders closes the ring gate, and pressurizing the rod-side chamber opens the ring gate. The drive cylinders could also be designed as synchronous cylinders.

[0014] The drive cylinders 3.1, 3.2 and 3.3 are hydraulically connected in parallel and are jointly connected to the pressure source 6 and the tank 7 via the directional control valve 8. The in Fig. The switching position shown in Figure 2 opens the ring contactor. Moving the directional control valve 8 to the left closes the ring contactor. Moving it to the right holds the ring contactor in its current position, typically the open position. The control unit is connected to the directional control valve 8 to control the position of the ring contactor. It is advantageous that the directional control valve 8 is designed so that, in the event of a failure of the control unit 5, it is automatically moved to the closed position, for example, by a mechanical spring.

[0015] Optionally, the drive group 3 includes a throttling device for each drive cylinder, one of which is designated 10. The throttling devices 10 serve to limit the closing speed of the ring gate in order to prevent a damaging pressure surge during an emergency closure. A throttling device 10 comprises at least one first throttle. Optionally, a throttling device 10 can comprise a further throttle and a pressure relief valve, wherein the further throttle and the pressure relief valve are arranged parallel to the first throttle, as shown in the Fig. 2 and Fig. Figure 3 shows that if a first throttle is blocked, the closing speed can be limited via the subsequent throttle. Alternatively, a common throttle device for all drive cylinders could be provided, which would then be located between the directional control valve 8 and the tank 7.

[0016] An alternative embodiment of the drive unit 3 consists in the omission of the directional control valve 8 and the provision of a separate proportional valve for each drive cylinder, which connects the corresponding drive cylinder separately to the pressure source 6 and the tank 7. In this case, the control unit 5 controls the proportional valves and can thus provide active synchronization control of the drive cylinders. In normal operation, the counterforces to be applied by the guide unit 4 are negligible in this embodiment. In the event of a failure of the control unit, the guide unit 4 then ensures the synchronization of the drive cylinders on its own, which is described in the Fig. The embodiment shown in Figure 2 with directional control valve 8 applies to both normal operation and emergency operation.

[0017] The hydraulic cylinders of guide group 4 are identical in design and hydraulically connected in a ring series configuration. Each guide cylinder comprises two chambers with as equal a hydraulically effective area as possible; that is, the guide cylinders are designed as synchronous cylinders. In the ring series configuration, the first chamber of one guide cylinder is connected to the second chamber of another guide cylinder. This hydraulically enforces the synchronous operation of the guide cylinders, as any deviation from synchronous operation results in large opposing forces that prevent a significant deviation. The synchronous operation of the guide cylinders is transmitted to the drive cylinders via the ring contactor through the mechanical connection.

[0018] The magnitude of the counterforces applied by the guide cylinders can be adjusted in the design of the device according to the invention by means of the size of the hydraulically effective surfaces of the guide cylinders. The counterforces, and thus the stiffness of the guide assembly, can also be advantageously increased by pressurizing the chambers of the guide cylinders. For this purpose, the guide assembly 4 optionally includes a pressure source which is located in Fig. 2, designated 9, is connected to the chambers of guide cylinders 4.1, 4.2, and 4.3 via check valves. The stiffness of guide assembly 4 can also be advantageously increased by using a water-based hydraulic fluid (e.g., so-called HFA fluids) instead of the commonly used oil-based fluid. The compression modulus of the hydraulic oil from the air chamber is approximately 1.0 GPa, while that of HFA fluid is 2.2 GPa.

[0019] Optionally, the guide group can include 4 sensors for monitoring the pressures and pressure gradients in the chambers of the guide cylinders 4.1, 4.2 and 4.3. Fig. Figure 2 indicates such a pressure sensor with the rectangle labeled 11. At least three sensors would be required to monitor all chambers of the guide cylinders. Pressure monitoring can, for example, detect whether an object is trapped under the ring gate when it closes. In this case, the pressure or pressure gradient in at least some of the guide cylinder chambers rises above a predefined limit. This allows the control unit performing the pressure monitoring to abort the closing process before any damage can occur to the device. Similar monitoring can also be performed during the opening process.

[0020] From the information related to the Fig. 1 and Fig. Based on the explanations given above, a person skilled in the art can easily derive further embodiments. One of these, already described above, involves doubling or multiplying the number of drive cylinders. For larger ring shooters, it can be advantageous to also increase the number of guide cylinders. These can be successively increased as desired, resulting in embodiments with four, five, six, or more guide cylinders. The number of drive cylinders is increased accordingly. Fig. 2. The guide cylinders are all hydraulically connected in a ring series, while the drive cylinders are operated in parallel. From four guide cylinders onwards, there are several possibilities for the sequence in which the guide cylinders are arranged in the ring series. For example, with four guide cylinders, there is one possibility in which the sequence in the ring series follows the arrangement of the guide cylinders in the circumferential direction of the ring gate, i.e., in the sequence 4.1, 4.2, 4.3, 4.4. However, for the highest possible rigidity of the guide assembly, a different sequence is more advantageous in which a crossing is made, i.e., 4.1, 4.3, 4.2, 4.4. The same applies to embodiments with more than four guide cylinders.

[0021] In addition to these directly from the embodiment according to the Fig. 1 and Fig. 2 derived embodiments are described in the Fig. 3, Fig. 4, Fig. 5, Fig. 6 to Fig. Seven further, differing embodiments are described. In these figures, only the guide group is shown, as what has been said so far still applies to the drive group.

[0022] Fig. Figure 4 shows an embodiment with the four guide cylinders 4.1, 4.2, 4.3 and 4.4, which are arranged in this order in the circumferential direction on the ring gate 2. Fig. Figure 4 can also be used to illustrate the embodiment described above with four guide cylinders, since the differing features only become apparent in Figure 4. Fig. 4 appear.

[0023] Fig. Figure 4 shows the hydraulic linkage of the guide group 4. Fig. 3. The four guide cylinders do not form a single ring series circuit, but rather two separate ring series circuits, with the crosswise positioned guide cylinders being interconnected, i.e., 4.1 with 4.3 and 4.2 with 4.4. The optional pressure supply can be provided for all guide cylinders together from a single pressure source 9.

[0024] Fig. Figure 5 shows an embodiment with the six guide cylinders 4.1, 4.2, 4.3, 4.4, 4.5 and 4.6, which are arranged in this order in the circumferential direction on the ring gate 2.

[0025] Fig. Figure 6 shows the hydraulic linkage of the guide group 4. Fig. 5. The six guide cylinders do not form a single ring series circuit, but rather two separate ring series circuits, with three guide cylinders connected together in each circuit, i.e., 4.1 with 4.3 and 4.5, and 4.2 with 4.4 and 4.6. This configuration for the two ring series circuits is not the only possibility. However, the configuration shown is particularly advantageous because the guide cylinders grouped together in a ring series circuit are as far apart as possible. The optional pressure supply can again be provided to all guide cylinders together from a single pressure source 9.

[0026] Fig. Figure 7 shows the hydraulic linkage of the guide group 4. Fig. 5. The six guide cylinders do not form a single ring series circuit, but rather three separate ring series circuits, with each pair of guide cylinders connected together, i.e., 4.1 with 4.4, 4.2 with 4.5, and 4.3 with 4.6. This selection for the three ring series circuits is not the only possibility. However, the selection shown is particularly advantageous because the guide cylinders grouped together in a ring series circuit are as far apart as possible, since they are located opposite each other. The optional pressure supply can again be provided to all guide cylinders together from a single pressure source 9.

[0027] Finally, it should be mentioned that, starting from the embodiment according to Fig. 1 and Fig.2. There is a further embodiment in which the number of guide cylinders is twice as large as the number of drive cylinders, so that in the circumferential direction, one drive cylinder follows every two guide cylinders. The feature "whereby at least one hydraulic cylinder (3.1, 3.2, 3.3) of the drive group (3) is arranged in a circumferential direction of the ring gate (2) between two adjacent hydraulic cylinders (4.1, 4.2, 4.3, 4.4, 4.5, 4.6) of the guide group (4)" is still fulfilled. The guide cylinders can still form one or more ring series circuits. Reference symbol list 1 Device for controlling a cylinder contactor 2 cylinder contactors 3 Group with drive function or drive group 3.1 Drive cylinder 3.2 Drive cylinder 3.3 Drive cylinder 4 Group with leadership function 4.1 Guide cylinder 4.2 Guide cylinder 4.3 Guide cylinder 4.4 Guide cylinder 4.5 Guide cylinder 4.6 Guide cylinder 5 Control unit 6 Pressure source 7 Tank 8-way valve 9 Pressure source 10 Throttle device 11 Pressure sensor

Claims

[1] Device (1) for controlling a cylinder gate (2) of a water power plant comprising a cylinder gate (2), at least six hydraulic cylinders (3.1, 3.2, 3.3, 4.1, 4.2, 4.3, 4.4, 4.5, 4.6) connected to the cylinder gate (2), each with two chambers, at least one pressure source (6), at least one valve (8) and a tank (7), characterized by, that at least three of the hydraulic cylinders (3.1, 3.2, 3.3) form a drive group (3) and the remaining hydraulic cylinders (4.1, 4.2, 4.3, 4.4, 4.5, 4.6) form a guide group (4), which is hydraulically separated from the drive group (3), and wherein at least one hydraulic cylinder (3.1, 3.2, 3.3) of the drive group (3) is arranged in a circumferential direction of the ring gate (2) between two adjacent hydraulic cylinders (4.1, 4.2, 4.3, 4.4, 4.5, 4.6) of the guide group (4), and wherein the hydraulic cylinders (4.1, 4.2, 4.3, 4.4, 4.5, 4.6) of the guide group (4) are designed as synchronous cylinders, and wherein the hydraulic cylinders (3.1, 3.2, 3.3) of the drive group (3) are hydraulically connected to the pressure source (6) and the tank (7) via at least one valve (8), and wherein each hydraulic cylinder (4.1, 4.2, 4.3, 4.4, 4.5, 4.6) of the guide group (4) is connected to at least one other hydraulic cylinder (4.1, 4.2, 4.3, 4.4, 4.5, 4.6) the guide group (4) is hydraulically connected to each other to form a ring series circuit. [2] Device (1) according to claim 1, wherein all hydraulic cylinders (4.1, 4.2, 4.3, 4.4, 4.5, 4.6) of the guide group (4) are hydraulically connected to each other in a single ring series circuit. [3] Device (1) according to claim 1, wherein the guide group (4) comprises four hydraulic cylinders (4.1, 4.2, 4.3, 4.4), of which two opposing hydraulic cylinders (4.1, 4.2, 4.3, 4.4) are hydraulically connected to each other in a ring series circuit, so that the guide group (4) comprises two ring series circuits. [4] Device (1) according to claim 1, wherein the guide group (4) comprises six hydraulic cylinders (4.1, 4.2, 4.3, 4.4, 4.5, 4.6), of which three hydraulic cylinders (4.1, 4.2, 4.3, 4.4, 4.5, 4.6) are hydraulically connected to each other in a ring series circuit, so that the guide group (4) comprises two ring series circuits. [5] Device (1) according to claim 1, wherein the guide group (4) comprises six hydraulic cylinders (4.1, 4.2, 4.3, 4.4, 4.5, 4.6), of which two hydraulic cylinders (4.1, 4.2, 4.3, 4.4, 4.5, 4.6) are hydraulically connected to each other in a ring series circuit, so that the guide group (4) comprises three ring series circuits. [6] Device (1) according to one of the preceding claims, wherein the device (1) comprises a further pressure source (9) which is connected via check valves to all chambers of the hydraulic cylinders (4.1, 4.2, 4.3, 4.4, 4.5, 4.6) of the guide group (4). [7] Device (1) according to one of the preceding claims, wherein the device (1) comprises at least one pressure sensor (11) and a control device (5) which are arranged such that the control device (5) can monitor a pressure in at least two chambers of the hydraulic cylinders (4.1, 4.2, 4.3, 4.4, 4.5, 4.6) of the guide group (4) by means of the pressure sensor (11) and can abort an opening or closing operation of the ring gate (2) if the monitored pressure or a gradient of a monitored pressure exceeds a predefined limit value. [8] Device (1) according to one of the preceding claims, wherein the device (1) comprises exactly one valve (8), and this valve (8) is designed as a directional control valve. [9] Device (1) according to any one of claims 1 to 7, wherein the device (1) comprises a proportional valve (8) for each hydraulic cylinder (3.1, 3.2, 3.3) of the drive group (3), and wherein each hydraulic cylinder (3.1, 3.2, 3.3) of the drive group (3) is connected to the pressure source (6) and the tank (7) via exactly one proportional valve (8). [10] Device (1) according to one of the preceding claims, wherein the hydraulic cylinders (4.1, 4.2, 4.3, 4.4, 4.5, 4.6) of the guide group (4) are operated with a water-based hydraulic fluid. [11] Hydroelectric power plant with a device according to one of the preceding claims.

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