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

Abstract

Device for controlling a ring gate, which ensures synchronous control in the event of a failure of the hydraulic machine's controller. The device according to the invention is characterized in that the hydraulic cylinders moving the ring gate are all identical, and that the synchronization of the hydraulic cylinders in emergency operation is hydraulically effected, with the hydraulic cylinders forming a single synchronized group.

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 ring 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 ring gate comprises a cylindrical ring that is moved axially to open and close. The diameter of the ring 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, but six are very common. Because the ratio of axial length to diameter of the ring is unfavorable, the ring tends to tilt when moving axially. 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 ring gate is also a safety element that must be able to shut down the hydraulic machine in the event of a malfunction. If the hydraulic machine's controller fails, jamming of the ring gate could no longer be reliably prevented. 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 ring gate. In this device, the hydraulic cylinders form at least two separate groups, each with at least two hydraulic cylinders. The hydraulic cylinders of 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 devices of this type 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 ring gate, which ensures synchronous control in the event of a failure of the hydraulic machine's controller. The device according to the invention is characterized in that the hydraulic cylinders moving the ring gate are all identical, and that the synchronization of the hydraulic cylinders in emergency operation is hydraulically controlled.

[0008] The problem is solved according to the invention by an embodiment according to the independent claim. Further advantageous embodiments of the present invention are found in the dependent claims.

[0009] The invention will be explained below with the aid of figures. The figures show, in detail: Fig. 1: Device for controlling a ring gate according to the state of the art Fig. 2: Device according to the invention in a first embodiment during normal operation Fig. 3: Device according to the invention in a first embodiment in emergency operation Fig. 4: Device according to the invention in a second embodiment during normal operation Fig. 5: Device according to the invention in a second embodiment in emergency operation Fig. 6: Device according to the invention in a second embodiment during normal operation Fig. 7: Device according to the invention in a second embodiment in emergency operation

[0010] Fig. Figure 1 shows a highly schematic representation of a device for controlling a ring gate according to the prior art. The device is designated 1 and the ring gate is designated 2. The device 1 comprises six hydraulic cylinders, one of which is designated 3. The rods of the hydraulic cylinders 3 are connected to the ring gate 2 such that extending the rods closes the ring gate 2. The device includes a control unit, which is designated 4. The control unit 4 controls the hydraulic cylinders 3 and, as long as it does not fail, ensures the synchronization of the hydraulic cylinders 3. The control unit 4 is usually an integral part of the controller of the higher-level hydraulic machine. The hydraulic cylinders 3 are numbered around their circumference using Roman numerals.

[0011] Fig. Figure 2 shows a device according to the invention in a first embodiment. The device is in a state corresponding to normal operation. The in Fig. The device shown in Figure 2 depicts only the parts relating to the hydraulic cylinders. The ring gate and the control unit are not shown. Fig. Figure 2 is not shown. The device according to the invention comprises six hydraulic cylinders, one of which is designated 3. The number of hydraulic cylinders could also be different. In general, the number of hydraulic cylinders is at least three.

[0012] The hydraulic cylinders 3 are identical in design and each comprises a housing, a piston, two rods, and three chambers. In a hydraulic cylinder 3, the first chamber is designated 3.1, the second chamber 3.2, and the third chamber 3.3. The first and second chambers 3.1 and 3.2 represent the chambers of a synchronous cylinder, meaning that the hydraulically effective areas in these chambers are of equal size. The piston of the hydraulic cylinder 3 is connected to a rod on both sides. A first rod protrudes downwards from the housing of the hydraulic cylinder. The ring gate (not shown) is attached to this rod. The second rod is completely enclosed by the housing of the hydraulic cylinder in every possible piston position. The third chamber 3.3 is located between the housing and the end of the rod; that is, the hydraulically effective area in the third chamber is the end face of the second rod located inside the housing.Each chamber (3.1, 3.2, 3.3) includes a connection through which the respective chamber can be supplied with hydraulic fluid.

[0013] The device according to the invention comprises a first accumulator, designated 5, and a tank, designated 9. The first accumulator 5 is at least partially filled with pressurized hydraulic fluid. The pressure in the first accumulator 5 is kept as constant as possible. For this purpose, a Fig. 2 pumps not shown are provided.

[0014] For controlling the ring gate during normal operation, the device includes a (3 / 2-way) proportional valve for each hydraulic cylinder. One of the proportional valves is designated 7. Each proportional valve 7 is connected to the first chamber 3.1 of the associated hydraulic cylinder, the first accumulator 5, and the reservoir 9. When the ring gate closes during normal operation, the proportional valves 7 regulate the flow of hydraulic fluid from the first chambers 3.1 into the reservoir. When the ring gate opens during normal operation, the proportional valves 7 regulate the flow of hydraulic fluid from the first accumulator 5 into the first chambers 3.1. During normal operation, the second chambers 3.2 of the hydraulic cylinders are each connected to the reservoir 9. The proportional valves 7 are controlled by the Fig. 2 control units not shown.

[0015] The device according to the invention comprises a second accumulator, designated by 6. The second accumulator 6 is at least partially filled with pressurized hydraulic fluid. The accumulator 6 is connected to the third chambers 3.3 of the hydraulic cylinders. The accumulator 6 connected to the third chambers 3.3 serves to increase the closing force. The closing force then consists of the weight of the ring gate and the pistons and rods of the hydraulic cylinders, and the pressure of the hydraulic fluid in the third chambers 3.3. In this way, closing is made possible even under full load of the hydraulic machine, which is generally not possible due to weight alone. When opening, the pressure force in the first chambers 3.1 works against the pressure force in the third chambers 3.3, whereby hydraulic fluid from the third chambers 3.3...3 is pressed into the second storage tank, and hydraulic fluid from the second chambers 3.2 flows into the tank 9.

[0016] In cases where the weight of the ring gate and the pistons and rods of the hydraulic cylinders alone is sufficient for closing under full load, the second accumulator 6 and the third chambers 3.3 of the hydraulic cylinders can be omitted. The hydraulic cylinders are then designed like conventional synchronous cylinders with the two chambers 3.1 and 3.2, i.e., the second rods protrude from the top of the hydraulic cylinder housing.

[0017] The device according to the invention comprises a switching device which is automatically activated in the event of a failure of the controller or control unit, i.e., in emergency operation, and enables synchronous control of the hydraulic cylinders independently of the control unit. The synchronous control of all hydraulic cylinders is hydraulic, with all hydraulic cylinders forming a single synchronized group. The switching device is used in conjunction with Fig. 3 described.

[0018] Fig. Figure 3 shows the embodiment of the device according to the invention. Fig. 2 in emergency operation. The switching device of the device according to the invention comprises one switching valve for each hydraulic cylinder, which can assume two switching states. In the Fig. 2 and Fig. Number 3 is one of the switching valves labeled 8. Fig. 2 the switching valves 8 are in a first switching position, which corresponds to normal operation, and in Fig. 3 the switching valves 8 are in a second switching position, which corresponds to emergency operation.

[0019] The switching device further comprises means that enable synchronous switching of all switching valves 8. These means can, for example, consist of all switching valves being arranged in a common housing and mechanically coupled. Another possibility is hydraulic switching of the switching valves via a common pilot valve. In any case, the switching valves 8 and the aforementioned means are designed such that the switching valves 8 assume the second switching state, which corresponds to emergency operation, when the power fails. This can be achieved, for example, by a mechanical spring and an electromagnet opposing the spring force. When the electromagnet is de-energized, the mechanical spring switches to the emergency operating state.The mechanical spring can act directly on the switching valves 8 if they are mechanically coupled, or on the common pilot valve if the coupling of the switching valves 8 is hydraulic.

[0020] If the switching valves 8, as in Fig. As shown in Figure 2, when the hydraulic cylinders are in the first switching position, the first chambers 3.1 of the hydraulic cylinders are each connected to the associated proportional valves 7, and the second chambers 3.2 of the hydraulic cylinders are each connected to the tank 9. When the switching valves 8 are in the first switching position, as shown in Figure 2, the hydraulic cylinders are connected to the tank 9. Fig. As shown in Figure 3, if the hydraulic cylinders are in the second switching position, then the first chambers 3.1 of the hydraulic cylinders are each separated from the associated proportional valves 7, and the second chambers 3.2 of the hydraulic cylinders are each separated from the tank 9. Instead, the hydraulic cylinders with their first and second chambers form a ring series connection, with the first chamber 3.1 of one hydraulic cylinder being connected to the second chamber 3.2 of another hydraulic cylinder. In such a ring series connection, the hydraulic cylinders can only be moved synchronously.

[0021] The order in which the hydraulic cylinders 3 are connected in series in the ring configuration is, in principle, arbitrary. However, it is particularly advantageous if the subsequent hydraulic cylinder 3 is arranged diagonally to the preceding hydraulic cylinder 3. With a total of 6 hydraulic cylinders, there are several equally viable options for this. In the Fig. 2 and Fig. 3 is represented by the Latin numerals, which refer to the Fig. 1. Refer to, by way of example, such a particularly advantageous sequence of connections is shown.

[0022] After the switching valves 8 are switched to the second switching state, the ring gate closes either under the influence of the weight force alone or supported by the pressure force in the third chambers 3.3, if these are provided.

[0023] Since the closing of the ring gate must not occur too quickly to avoid a pressure surge, the device according to the invention includes a throttling device for each hydraulic cylinder, which is arranged such that it can throttle the volume flow of hydraulic fluid that flows from the first chambers 3.1 into the second chambers 3.2 when the changeover valves are in the second switching state. Fig. 2 and Fig. 3 is one of the throttling devices designated 10. The throttling devices 10 are each arranged between the first chamber 3.1 of the associated hydraulic cylinder and the associated changeover valve 8. Alternatively, the throttling devices 10 can also each be arranged between the second chamber 3.2 of the associated hydraulic cylinder and the associated changeover valve 8.

[0024] A throttling device 10 comprises at least one first throttle. Optionally, a throttling device 10 may 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 undisturbed functionality of the device according to the invention can be ensured via the further throttle.

[0025] Fig. Figure 4 shows a device according to the invention in a second embodiment during normal operation. As in the first embodiment, the device according to the invention comprises at least three identically designed hydraulic cylinders 3 (in Fig. 4 (there are six of them again), a storage tank 5, a reservoir 9, a switching device, and one proportional valve 7 for each hydraulic cylinder 3. In contrast to the first embodiment, the hydraulic cylinders 3 in the second embodiment are designed as differential cylinders, with the first chamber 3.1 being the rod-side chamber and the second chamber 3.2 being the piston-side chamber. The second chamber 3.2 of the hydraulic cylinders each includes an additional second connection. In normal operation, the in Fig. 4. The control device (not shown) controls the movement of the ring gate as described above via the proportional valves 7, wherein the additional second connections of the second chambers 3.2 are ineffective, i.e., closed. The switching device of the device according to the invention in the second embodiment is used in conjunction with Fig. 5 described.

[0026] The second chambers 3.2 could just as easily have only one connection. Then the lines running into the Fig. 4 and Fig. 5 are connected to the additional second connection, to the lines that are in the Fig. 4 and Fig. 5 connect to the first port. The second port can then be omitted. The representation with two ports in the Fig. 4 and Fig. In any case, number 5 offers the advantage of greater clarity.

[0027] Fig. Figure 5 shows the second embodiment of the device according to the invention. Fig. 4 in emergency operation. As in the first embodiment, the switching device comprises one switching valve 8 for each hydraulic cylinder, which can assume two switching states. In Fig. 4 the switching valves 8 are in a first switching position, which corresponds to normal operation, and in Fig. 5 the switching valves 8 are in a second switching position, which corresponds to emergency operation.

[0028] The device according to the invention in the second embodiment comprises a synchronization device, which is designated 11. The synchronization device 11 comprises one synchronization cylinder for each hydraulic cylinder 3. All synchronization cylinders each comprise a housing and a movable piston, with a chamber arranged between the housing and the piston. In the Fig. 4 and Fig. 5 is one of these chambers, designated 11.1. The pistons of the synchronization cylinders are mechanically connected to each other, so that the pistons can only move together within the housings. The synchronization cylinders are designed such that, during a simultaneous movement of the pistons, the amount of hydraulic fluid flowing into or out of chambers 11.1 is the same for each synchronization cylinder. This means that the hydraulically effective area of ​​the pistons of the synchronization cylinders must be the same for each cylinder.

[0029] If the switching valves 8, as in Fig. As shown in Figure 4, when the hydraulic cylinders are in the first switching position, the first chambers 3.1 of the hydraulic cylinders are each connected to the associated proportional valves 7, and the second chambers 3.2 of the hydraulic cylinders are each connected to the tank 9, and the additional second connections of the second chambers 3.2 are closed. When the switching valves 8 are in the first switching position, as shown in Figure 4, the hydraulic cylinders are connected to the tank 9. Fig. As shown in Figure 5, when the switching valves 8 are in the second switching position, chambers 3.1 and 3.2 of the hydraulic cylinders 3 are each short-circuited, i.e., in each hydraulic cylinder 3, the first chamber 3.1 is connected to the second chamber 3.2, with a throttle device 10 arranged in this connection. Furthermore, in the second switching position of the switching valves 8, the additional second port of the second chamber 3.2 of a hydraulic cylinder 3 is connected to one of the chambers 11.1 of a synchronization cylinder.

[0030] The above statements regarding the first embodiment apply to the synchronous and automatic switching of the switching valves 8.

[0031] Since the hydraulic cylinders 3 in the second embodiment are designed as differential cylinders, more hydraulic fluid is absorbed by the second chambers 3.2 during a piston movement in the closing direction than is discharged by the first chambers 3.1. In the second switching position of the changeover valves, this differential volume originates from the corresponding synchronization cylinders of the synchronization device 11. The mechanical connection of the pistons of the synchronization cylinders, via the hydraulic connection between the synchronization cylinders and the hydraulic cylinders 3, ensures that the hydraulic cylinders 3 can only move synchronously.

[0032] The throttling devices 10 could also be arranged in the connecting lines between the synchronization cylinders and the changeover valves 8 or in the connecting lines between the changeover valves 8 and the additional second connections of the second chambers 3.2. In these cases, they only act in the second switching position of the changeover valves 8, which is sufficient, however, since the closing time can be ensured by the control device during normal operation.

[0033] In the second embodiment, closing can also occur solely under the influence of gravity. In this case, it is advantageous if the synchronization cylinders of the synchronization device are arranged such that the weight of the interconnected pistons of the synchronization cylinders assists the closing. This is the case when the synchronization cylinders are arranged in reverse to the configuration shown in the [reference to the previous example]. Fig. 4 and Fig. 5 is shown, i.e., reflected across a horizontal line.

[0034] Closing can also be assisted by a pressure force. In this case, the synchronization device 11 includes another hydraulic cylinder, which, for differentiation, is called the closing pressure cylinder. The closing pressure cylinder comprises a housing and a movable piston, with a chamber arranged between the housing and the piston. In the Fig. 4 and Fig. 5 is the chamber of the closing pressure cylinder, designated 11.2. The piston of the closing pressure cylinder is connected to the pistons of the synchronization cylinders in such a way that they can only be moved together. Furthermore, the switching device includes an additional switching valve, which can assume two switching states and is located in the Fig. 4 and Fig. 5 is labelled with 12. In Fig. 4 The changeover valve 12 is in a first switching position, in which it separates the storage tank 5 from the chamber 11.2 of the closing pressure cylinder. In Fig. In position 5, the changeover valve 12 is in a second switching position, in which it connects the accumulator 5 to the chamber 11.2 of the closing pressure cylinder. The pressure force generated in the closing pressure cylinder thereby assists the closing process of the ring gate. The switching of the additional changeover valve 12 must be synchronized with the switching of the other changeover valves 8. Similar means to those described above can be used for this purpose.

[0035] Since there are no particularly preferred sequences for the hydraulic cylinders in the second embodiment, numbering with Latin numerals was omitted. Fig. 4 and Fig. 5 is omitted. It should also be noted that the lines which are in the Fig. 4 and Fig. 5 of the switching valves 8 lead to the tank 9, and can just as easily be routed via the corresponding proportional valves 7 to enable pressure-assisted closing during normal operation. The in Fig. In contrast, the arrangement shown in section 4 only allows closing via weight force during normal operation.

[0036] In the Fig. 6 and Fig. Figure 7 shows a third embodiment, which in some respects represents a combination of the first and second embodiments. Fig. Figure 6 shows the third embodiment in normal operation. There is no difference here compared to the second embodiment; that is, the following applies: Fig. 6 exactly what's needed Fig. 4 was said. Fig. Figure 7 shows the third embodiment in emergency mode. Unlike Fig. 5. The hydraulic cylinders are in Fig. 7 in the second switching state of the changeover valves 8 are additionally connected in series in a ring circuit, which further improves the synchronization of the hydraulic cylinders. This means that, unlike Fig. 5. In the second switch position, the first and second chambers of the hydraulic cylinders 3 are no longer connected to each other. However, the first chamber of a hydraulic cylinder (or the second chamber of the subsequent hydraulic cylinder) is each connected to a chamber of a synchronization cylinder. Regarding the ring series connection, what was stated above in connection with... Fig. 3 was said.

[0037] The first embodiment is characterized by its simple design. It is preferable when sufficient space is available for the synchronous cylinders. The second and third embodiments are more complex and are suitable for use when insufficient space is available for the first embodiment. Reference symbol list 1 Device for controlling a ring gate 2 Ring-Gate 3 hydraulic cylinders 3.1 First Chamber 3.2 Second Chamber 3.3 Third Chamber 4 Control unit 5 storage 6 storage 7 Proportional valve 8 Diverter valve 9 Tank 10 Throttle device 11 Synchronization device 11.1 Chamber Synchronization Cylinder 11.2 Chamber locking cylinder 12 Diverter valve

Claims

[1] Device (1) for controlling a ring gate (2) of a hydroelectric power plant, wherein the device (1) comprises a control unit (4), at least one accumulator (5), a tank (9), at least three hydraulic cylinders (3) and for each hydraulic cylinder (3) a proportional valve (7) and a throttle device (10), and wherein each hydraulic cylinder (3) comprises a first chamber (3.1) and a second chamber (3.2), and wherein each proportional valve (7) is connected to the accumulator (5) and the tank (9), and wherein the control unit (4) is configured such that the control unit (4) can control the proportional valves (7), characterized by, that the device (1) comprises a switching device which is configured such that the switching device can effect hydraulic synchronization of the hydraulic cylinders (3) independently of the control device (4), in which all hydraulic cylinders (3) form a single synchronized group, and wherein the switching device comprises a switching valve (8) for each hydraulic cylinder (3), and wherein each switching valve (8) has a first and a second switching position, and wherein each switching valve (8) is configured and arranged such that in the first switching position it can connect a first chamber (3.1) of a hydraulic cylinder (3) to the associated proportional valve (7) and a second chamber (3.2) of a hydraulic cylinder (3) to the tank (9), and in the second switching position a first chamber (3.1) of a hydraulic cylinder (3) to the associated proportional valve (7) and a second chamber (3.2) of a hydraulic cylinder (3) from the tank (9), and wherein the switching device comprises means which are designed such that the switching valves (8) can be switched synchronously, and wherein the throttling devices (10) are arranged such that they can limit a closing time of the ring gate (2) at least when the switching valves (8) are in the second switching position. [2] Device (1) according to claim 1, wherein the hydraulic cylinders (3) are designed such that the hydraulically effective area in the first chamber (3.1) is the same size as the effective area in the associated second chamber (3.2), and wherein the switching valves (8) are designed and arranged such that in the second switching position they can connect the first chamber (3.1) of one hydraulic cylinder (3) with the second chamber (3.2) of another hydraulic cylinder (3) in order to connect the hydraulic cylinders (3) together in such a way that they form a ring series circuit. [3] Device (1) according to claim 2, wherein the hydraulic cylinders (3) each comprise a third chamber (3.3), and wherein the device (1) comprises a further accumulator (6) which is connected to the third chambers (3.3) of all hydraulic cylinders (3). [4] Device (1) according to claim 1, wherein the hydraulic cylinders (3) are designed such that the hydraulically effective area in the first chamber (3.1) is smaller than the effective area in the associated second chamber (3.2), and wherein the device (1) comprises a synchronization device (11), and wherein the synchronization device (11) comprises a synchronization cylinder for each hydraulic cylinder (3), and wherein each synchronization cylinder comprises a chamber (11.1) and a piston with a hydraulically effective area, and wherein the hydraulically effective area of ​​the pistons in the chambers (11.1) of all synchronization cylinders is the same size, and wherein the pistons of all synchronization cylinders are mechanically connected to each other, and wherein the switching valves (8) are designed and arranged such that in the second switching position they connect the first chamber (3.1) with the second chamber (3.2) in all hydraulic cylinders (3).2) connect and connect the second chamber (3.2) to the chamber (11.1) of a synchronization cylinder. [5] Device (1) according to claim 1, wherein the hydraulic cylinders (3) are designed such that the hydraulically effective area in the first chamber (3.1) is smaller than the effective area in the associated second chamber (3.2), and wherein the device (1) comprises a synchronization device (11), and wherein the synchronization device (11) comprises a synchronization cylinder for each hydraulic cylinder (3), and wherein each synchronization cylinder comprises a chamber (11.1) and a piston with a hydraulically effective area, and wherein the hydraulically effective area of ​​the pistons in the chambers (11.1) of all synchronization cylinders is the same size, and wherein the pistons of all synchronization cylinders are mechanically connected to each other, and wherein the switching valves (8) are designed and arranged such that in the second switching position they connect the first chamber (3.1) of a hydraulic cylinder (3) to the second chamber (3.2) of another hydraulic cylinder (3) to connect the hydraulic cylinders (3) to each other in such a way that they form a ring series circuit, and wherein the switching valves (8) are designed and arranged in such a way that in the second switching position they can connect the second chamber (3.2) in all hydraulic cylinders (3) to the chamber (11.1) of a synchronization cylinder. [6] Device (1) according to one of claims 4 or 5, wherein the synchronization device (11) comprises a closing pressure cylinder with a chamber (11.2) and a piston, and wherein the piston of the closing pressure cylinder is mechanically connected to the pistons of the synchronization cylinders, and wherein the switching device comprises an additional switching valve (12) which has a first and a second switching position, and wherein the additional switching valve (12) is designed and arranged such that in the first switching position it can disconnect the chamber (11.2) of the closing pressure cylinder from the accumulator (5) and in the second switching position it can connect the chamber (11.2) of the closing pressure cylinder to the accumulator (5), and wherein the switching device comprises means which are designed such that the switching valves (8) and the additional switching valve (12) can be switched synchronously.

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