Floating hydroelectric power plant for rivers and method of maintaining such a power plant

Abstract

Floating hydroelectric power station for watercourses and method for maintaining such a power station Floating hydroelectric power station, intended to be partially submerged in a watercourse, comprising a flotation member (10) comprising at least two hulls (12) coupled by a frame (14) comprising a floor (15) extending in a main plane (B), and, for each hull (12), a connecting element (30 to 33) connecting the hull (12) to the floor (15);a channel (20) comprising two turbines (36) mounted counter-rotating along respectively two axes of rotation (X, X') defining together a secondary plane (C), and telescopic slides (50, 51), each telescopic slide being located entirely under the main plane (B) and connecting one of the connecting elements of the frame (14) to the channel (20), the telescopic slides being configured to allow a translation of the channel (20) in a direction (Z) perpendicular to the main plane (B), so that an upper face (FS) of the channel (20) remains under the main plane (B). Figure for the abstract: Fig.1;

Description

Title of the invention: Floating hydroelectric power station for waterways and method for maintaining such a power station Technical field

[0001] The present invention relates to floating power plants for waterways, and more particularly for shallow rivers. STATE OF THE ART

[0002] Floating hydroelectric power plants, referred to hereinafter as floating hydro turbines, which can be used in shallow rivers (for example between 2 m and 4 m), as well as in rivers with moderate speeds, but nevertheless greater than 1.5 m / s, can be deployed in many sites. Such hydro turbines have the advantage of being able to meet the electrical energy needs of sites outside the electricity grid, in Europe because they are difficult to access or isolated, and in developing countries because of an incomplete electrification network. Conversely, the targeted powers range from a hundred watts to around twenty kilowatts corresponding to the upper limit defining pico electricity.

[0003] Some hydro turbines have an emerged platform, and are attached by various mooring lines (rope, cable, chain etc.) to any fixed device at the bottom of a river or to pre-existing land structures such as bridge piers on said river. They are distinguished from numerous variants of river hydro turbines, without a platform, which are also called floating. Indeed, although these variants have components that provide them with buoyancy greater than unity, they are kept completely submerged, according to a depth and orientation controlled by more or less complex systems in which ballast tanks are generally included, filled or purged of the surrounding water, as in patent US2010327583. These hydro turbines intended to be completely submerged, are designed for significant depths, whether for rivers or for tidal currents.They are inversely distinguished from hydro turbines where the turbine is positioned close to the surface of the water as in patent US2007020097, or even crossing the surface of the water, as in patent DE102011084017A1.

[0004] Finally, certain floating hydro turbines of the prior art are poorly suited to shallow rivers, because they do not satisfy the following two constraints: a. the available resource being modest, it is advantageous for the architecture of the turbomachine (i.e. a device comprising one or more turbines) to adapt to the section of the watercourse at shallow depth and to its low speed; it is therefore desirable to locally accelerate the flow near the turbine via fairings while respecting the flattened wet section of the river; b. It is also important that the generator does not occupy a high position above the floating platform, as is the case in patent application CA2696758, because in operating mode the following disadvantages appear: loss of maneuverability in places that are difficult to access, visual nuisances, and the possibility of acts of vandalism. It is therefore preferable that said platform be as uncluttered as possible.

[0005] Realistic solutions in the power plant disclosed in patent application EP3707371 have been proposed to satisfy these two constraints. However, in this power plant, as in all other power plants of the prior art, problems arise, in particular problems of maintenance of the elements of a hydro turbine. For example, current hydro turbines may appear deficient in terms of being able to easily carry out basic maintenance on site concerning said turbines and their powertrain. Then, for major repairs, these hydro turbines are difficult to tow by river boats, for their transport to a maintenance or repair site on the shore, common, if necessary, to an entire park, and then be able to be put back in place, just as easily, within the river.

[0006] To operate in optimal conditions on the platform, several systems for lifting / replacing the turbines exist to carry out necessary maintenance operations. We can cite the French patent application FR3079002 which discloses a hydro turbine equipped with floats, a propeller supported by a mast and a jack allowing the mast to be raised by rotation around an axis located above the floats. But such a hydro turbine does not have a platform, and must be towed along the banks of the watercourse to carry out maintenance operations. We can also cite, for example, the patent application US2010176595 which discloses a lifting system for moving the turbine by pivoting around an axis of rotation located above the floats of the power plant.Other tidal turbines have platforms equipped with an equivalent lifting system, but the platform must include a central opening to pass the turbine into the raised position, which reduces the space available on the platform and limits maintenance operators from moving around the turbine, or placing repair and testing tools that can be cumbersome. For example, patent application US2018087484 discloses a crane fixed to the platform to facilitate the pivoting of the turbine around the rotation axis located on the sides of the platform. The lifting system is cumbersome and an imbalance of the platform appears when raising. the turbine. We can also cite international application WO2014064067Al which discloses a floating tidal turbine comprising a propeller mounted to rotate at the base of a mast around a horizontal axis of rotation, an electric generator resting on a floor above the water and a maneuvering system provided for raising or lowering a mast which passes through the floor. But the floor is cluttered by the generator and more so when the mast is raised above the floor.

[0007] These systems are mechanically complex, often heavy and / or large. In addition, whether in a repair or transport situation, these lifting systems, as well as the generator, occupy a significant space on the platform connecting the floats and affect the transport of the hydro turbine to or from the repair dock.

[0008] In order to reduce maintenance operations on the turbines, the tidal turbines can be equipped with anti-debris protection systems to protect the turbines. Indeed, medium or low debris, consisting mainly of dead leaves, twigs and aquatic vegetation or of anthropogenic origin, which, being mainly submerged, can directly affect the operation of the turbines. Thus, the twin rotors of patent application EP3707371, placed in a channel of rectangular section, are protected by an anti-debris system placed upstream of the mouth of the channel. This system comprises four cylindrical surfaces composed of a succession of parallel bars. These bars block the irruption of debris within the submerged channel and also participate in the regulation of the incident current by breaking up large turbulent structures.However, these grids become clogged in the more or less long term and require cleaning to keep them clean. This cleaning, also called screening, is essential for all inlet grid systems; it should also be remotely controllable. But patent EP3707371 does not disclose any system that can facilitate cleaning of the anti-debris system on site, i.e. when the tidal turbine is in the operating position.

[0009] Furthermore, other larger floating debris can affect either the floats or the structures connecting the floats to the turbomachine. To deflect large floating debris from the platform, a partially submerged structure in the form of two elongated V-shaped plates, called by the acronym RDDP (“Research Debris Diversion Platform” in English), is used. But such a structure tends to block the incident current. In addition, French patent application FR3079002 discloses a similar anti-debris system, however this system does not protect the turbine in the fully submerged position. There is therefore a difficulty in simultaneously ensuring protection against both types of debris, at low cost, without altering performance and with minimal human intervention.

[0010] Thus, we observe that the different solutions which are provided by the power stations the prior art in an attempt to resolve the aforementioned drawbacks, are not sufficiently compatible with architectural properties ensuring strong passive stability of the nominal operating regime, primarily with respect to pitch and yaw disturbances. Indeed, in the prior art this stability is often obtained by dimensioning a bulky flotation member, not very economical in material, leading to excessive manufacturing and transport costs. This dimensioning may result from a poor connection of the tidal turbine with its mooring line(s), but it may also result from the need to support the weight of the entire set of turbines of the lifting system and / or the elevation of the center of gravity of the turbomachine during its lifting.

[0011] An object of the present invention is therefore to propose means for overcoming the drawbacks mentioned above, and in particular, to propose means for improving the maintenance of floating hydroelectric power stations.

[0012] Another object is to improve maintenance at the operating site of the power plant or on the bank of the watercourse.

[0013] Another object is to reduce the frequency of maintenance operations.

[0014] Other objects, features and advantages of the present invention will become apparent from a consideration of the following description and accompanying drawings. It is understood that other advantages may be incorporated. SUMMARY

[0015] To achieve this objective, a floating hydroelectric power station is proposed, intended to be partially submerged in a watercourse having a current direction, the floating hydroelectric power station comprising a flotation member comprising at least two hulls coupled by a frame, the frame comprising a flat part, called a floor, an upper face of the floor extending in a main plane, and, for each hull, the frame comprises a connecting element connecting the hull to the floor.

[0016] The plant further comprises: a. a channel having a converging then diverging section in the direction of the current, the channel comprising a pair of side fairings connected by an upper plate and a lower plate parallel to the main plane; b. two turbines mounted counter-rotating within the channel according to two axes of rotation respectively defining together a secondary plane, perpendicular to the main plane, each turbine having at least two blades and being coupled to at least one generator carried by the power station; c. a mooring line configured to connect the channel to an anchoring system intended to be fixed to the bed or a bank of the watercourse; and d. a first pair of telescopic slides located upstream of the plane secondary according to the direction of the current, and a second pair of telescopic slides located downstream of the secondary plane, each telescopic slide being located entirely under the main plane and connecting one of the connecting elements of the frame to the channel, the telescopic slides being configured to allow a translation of the channel relative to the frame in a direction, called displacement, perpendicular to the main plane and so that an upper face of the channel remains under the main plane.

[0017] Thus, a floating hydro turbine is provided which facilitates the maintenance operations necessary for its operation. Such a hydro turbine makes it possible to bring the canal containing the elements to be maintained on site closer, for example cleaning a turbine or repairing a generator, to facilitate access, while avoiding cluttering the floor on which the operators work. Advantageously, such a hydro turbine makes it easier to tow it to a bank of the watercourse to be able to carry out more important maintenance operations, such as for example replacing an element of the canal, such as a turbine. Such a hydro turbine is particularly suitable for being towed near the banks of shallow rivers, the depth of which can vary from 2 to 4 m.

[0018] According to another aspect, there is provided a method of maintaining a floating hydroelectric power station as defined above, comprising: a. placing the floating hydroelectric power plant in operating position on an operating site floating on the surface of a watercourse, and b. a maintenance position comprising a translation of the channel relative to the reinforcement in the direction of movement, so that an upper face of the channel remains below the main plane and occupies an emerged position. BRIEF DESCRIPTION OF THE FIGURES

[0019] The aims, objects, as well as the characteristics and advantages of the invention will emerge more clearly from the detailed description of an embodiment thereof which is illustrated by the following accompanying drawings in which:

[0020] [Fig.l] [Fig.l] schematically illustrates a perspective view of an embodiment of a floating hydroelectric power station;

[0021] [Fig.2] [Fig.2] schematically illustrates a perspective view of one embodiment of the channel;

[0022] [Fig.3] [Fig.3] schematically illustrates a partial perspective view of the power station illustrated in [Fig.l] with a view along a section in a plane AB perpendicular to the secondary plane C and passing through the axis X' of a turbine;

[0023] [Fig.4] [Fig.4] schematically illustrates a perspective view of an embodiment of an anti-debris system in a first position;

[0024] [Fig.5] [Fig.5], schematically illustrates a perspective view of the anti-debris system illustrated in [Fig.4], in a second position;

[0025] [Fig.6] [Fig.6] schematically illustrates a perspective view of another embodiment of a floating hydroelectric power station;

[0026] [Fig.7] [Fig.7] schematically illustrates a side view of another embodiment of a floating hydroelectric power station in which the channel occupies a submerged position;

[0027] [Fig.8] [Fig.8] schematically illustrates a top view of another embodiment of a floating hydroelectric power station;

[0028] [Fig.9] [Fig.9] schematically illustrates a sectional view of an embodiment of a telescopic slide;

[0029] [Fig. 10] [Fig. 10] schematically illustrates a sectional view of another embodiment of a telescopic slide;

[0030] [Fig. 11] [Fig. 11] schematically illustrates a perspective view of another embodiment of a floating hydroelectric power station in which the channel occupies an emerged position.

[0031] The drawings are given as examples and are not limiting of the invention. They constitute schematic representations of principle intended to facilitate the understanding of the invention and are not necessarily on the scale of practical applications. DETAILED DESCRIPTION

[0032] Before beginning a detailed review of embodiments and implementations of the invention, optional features are set out below which may optionally be used in combination or alternatively.

[0033] According to one example, the floor comprises a main opening and the unit comprises a lifting system comprising a connecting element connected to the channel and passing through the main opening, the lifting system being configured to move the channel in translation according to the direction of movement.

[0034] According to one example, the telescopic slides are configured to occupy a deployed position in which the telescopic slides maintain the channel in a submerged position and a raised position in which the telescopic slides maintain at least the upper face of the channel in an emerged position.

[0035] According to one example, each telescopic slide comprises a lower part fixed to the channel, an upper part fixed to one of the connecting elements and at least one intermediate part movable in translation according to the direction of movement relative to to the lower and upper parts.

[0036] According to one example, the lower portion of at least one slide comprises a ball bearing configured to guide said at least one intermediate portion in movement according to the direction of movement.

[0037] According to one example, the channel comprises an upper housing mounted on the upper plate and a lower housing mounted on the lower plate, at least one of the upper and lower housings being configured to house the at least one generator.

[0038] According to one example, said at least one generator is housed within the upper casing.

[0039] According to one example, the upper plate of the channel comprises at least one secondary opening opening into the upper casing.

[0040] According to one example, said at least one secondary opening is located in line with the main opening in the direction of movement.

[0041] According to one example, the plant comprises an anti-debris system comprising a lower grid located upstream of the channel and having a downstream edge mounted on the lower plate of the channel and an upstream edge located upstream of the downstream edge, and an upper plate located upstream of the channel and having a downstream edge mounted on the upper plate of the channel and an upstream edge located upstream of the downstream edge of the upper grid, the upper grid being shaped such that its upstream edge is configured to be in contact with the upstream edge of the lower grid.

[0042] According to one example, the upper grid comprises several bars located on either side of a middle bar having a “Y” shape that flares out towards the upstream edge of the upper grid so that the middle bar forms a passage for the mooring line.

[0043] According to one example, the upper grid is pivotally mounted about a transverse axis contained in a secondary plane parallel to the main plane, between a first position in which the upstream edge of the upper grid is located below the secondary plane so that the upper grid can retain debris carried by the watercourse, and a second position in which the upstream edge of the upper grid is located in or above the secondary plane so that the retained debris can be carried by the watercourse above the channel.

[0044] According to one example, the central unit comprises a control device configured to pivotally move the upper grid about the transverse axis.

[0045] According to one example, the control device comprises a cylinder, preferably a pneumatic cylinder, and preferentially a cylinder with a movable rod.

[0046] According to one example, the central unit comprises an electronic control unit configured to control the control device so as to bring the upper grid into the second position at a determined frequency.

[0047] According to one example, the electronic control unit is configured to determine a power difference between a current electrical power supplied by said at least one generator and a reference power corresponding to an electrical power supplied by said at least one generator in the absence of debris on the upper grid, the electronic control unit being further configured to calculate the determined frequency from the power difference.

[0048] According to one example, the method comprises, before placing in the operating position, an installation comprising: a. towing of the floating hydroelectric power station on the surface of the watercourse, from a bank of the watercourse towards the operating site, the towing comprising a translation of the channel relative to the frame in the direction of movement, so that an upper face of the channel remains below the main plane and occupies an emerged position; b. mooring of the floating hydroelectric power station by connecting the canal, by the mooring line, to an anchoring system fixed on the bed or a bank of the watercourse, and c. an operation, comprising a translation of the channel relative to the armature in the direction of movement, so that an upper face of the channel remains below the main plane and occupies a submerged position

[0049] According to one example, the method comprises, after placing in maintenance position, an uninstallation comprising: a. disconnection of the mooring line with the anchoring system; and b. towing of the floating hydroelectric power plant on the surface of the watercourse, from the operating site to a bank of the watercourse.

[0050] In Figures 1 to 11, a floating hydroelectric power station 1 is shown, intended to be partially submerged in a watercourse having a current direction D. The power station 1 is particularly suitable for rivers, and more particularly for shallow rivers, i.e. having a depth of between 2 m and 4 m. The power station 1 comprises a flotation member 10, a frame 14, a channel 20 and a mooring line 80.

[0051] The flotation member 10 comprises at least two hulls 12 coupled by the frame 14. The flotation member 10 has a catamaran-type architecture. The hulls 12 form two floats elongated in the direction of the current D. For example, the hulls 12 are parallel to each other with respect to a median plane A. The frame 14 comprises a flat part 15, called the floor, an upper face of the floor 15 extending in a main plane B. The floor 15 is intended to be horizontal in the absence of swell. In addition, the frame 14 comprises, for each hull 12, a connecting element 30 to 33 connecting the hull 12 to the floor 15. The connecting elements 30 to 33 support the floor 15. The floor is emerged horizontally in nominal mode, that is to say in the so-called zero trim position. The frame 14 has an overall arch shape. Preferably, each shell 12 is provided with a longitudinal frame 16, extending in a plane parallel to the median plane A, and comprising parallel and superimposed bars. The two longitudinal frames 16 are fixed to the frame 14,

[0052] The channel 20 has a convergent then divergent section in the direction of the current D. The channel 20 comprises a pair of lateral fairings 22 connected by an upper plate 24 and a lower plate 26 parallel to the main plane B. For example, the lateral fairings 22 have cylindrical surfaces generated by a vertical straight line resting on two wing profiles with strong curvature, symmetrical with respect to the median plane A. The framework of a lateral fairing 22 may comprise vertical sheet metal plates, of height equal to the height of the fairing 22, associated so as to match the average line of the profile adopted by the fairing 22. A lateral fairing 22 may further comprise transverse reduced plates connected by welding to the preceding longitudinal plates and some of which are also connected to U-shaped profiles, providing the external grooves which are thus locally reinforced.Advantageously, a side fairing 22 comprises pre-cut foam blocks, inserted between the sheet metal plates and the transverse reduced plates in order to reconstitute the desired hydrodynamic profiles. Links can be added between the vertical sheet metal plates and the upper 24 and lower 26 plates. The assembly comprising the side fairings 22 and the upper 24 and lower 26 plates can form a single-piece frame.

[0053] The mooring line 80 configured to connect the channel 20 to an anchoring system intended to be fixed on the bed or a bank of the watercourse. The mooring line 80 makes it possible to hold the power plant against the current. The line 80 may comprise an upstream portion, according to the direction of the current D, configured to be connected to one or more immovable objects of the anchoring system. The mooring line 80 is contained in the median plane A perpendicular to the main plane B.

[0054] Furthermore, the power plant 1 comprises two turbines 36 mounted counter-rotating within the channel 20 along respectively two axes of rotation X, X' together defining a secondary plane C. The axes of rotation X, X' are parallel to each other. Preferably, the turbines are identical to limit the pitching of the power plant 1 in operation. The secondary plane C is perpendicular to the main plane B. The secondary plane C is vertical in operation (and in the absence of swell), that is to say in an electricity production situation. Each turbine 36 has at least two blades 38. Each turbine 36 is coupled to at least one generator 48 carried by the power plant 1. The channel 20 can further comprising an upper casing 25 mounted on the upper plate 24 of the channel 20, and a lower casing 27 mounted on the lower plate 26 of the channel 20. Advantageously, at least one of the upper 25 and lower 27 casings is configured to house at least one generator 48. Alternatively, the power plant 1 comprises two generators 48 respectively coupled to the two turbines 36. Preferably, the generator(s) 48 are housed within the upper casing 25. In this case, each turbine 36 is rotatably mounted on a generator 48 by an upper pivot connection, and is rotatably mounted lower by a lower pivot connection located within the lower casing 27.

[0055] For example, the upper 25 and lower 27 casings are limited by uniform walls transversely and symmetrically to each other with respect to a horizontal plane of the channel 20, parallel to the main plane B, located halfway between the upper 24 and lower 26 plates. The casings 25, 27 may have a profile such that the sections parallel to the median plane A form a convex plane profile in the direction of the current D. The casings 25, 27 each have a flat face fixed under and on the upper 24 and lower 26 plates respectively, and a convex face connecting upstream with said flat faces by a leading edge 28.

[0056] For example, the upper casing 25 contains generators 48 advantageously with direct drive and of discoid shape, and also contains an electronic control unit 201, illustrated in [Fig. 5], configured to regulate the rotation speed of one of the two generators 48, called master, via a rotation speed search system ensuring the maximum extracted power for a given incident speed of the current on the rotors, and regulating another generator 48 to rotate at the same rotation speed and in the same angular position relationship.

[0057] The channel 20 further comprises a profiled central part 17 extending longitudinally in the median plane A, separating the two turbines 36 and fixed between the two upper 24 and lower 26 plates. The central part 17 has a leading edge 18 forming a cylindrical column on which the mooring line 80 under tension (cable, chain, rope, rod, etc.) is attached at a point O. The attachment point O may comprise a pivot connection 19 with an axis perpendicular to the median plane A. For example, the pivot connection 19 is attached to a nut of a screw-nut system, the nut being housed within said column so that a rotational movement of the screw is transformed into a translational movement for the nut and allows fine adjustment of the height position of the pivot connection 19.

[0058] In particular, the central unit 1 comprises a first pair of telescopic slides 50, 51 located upstream of the secondary plane C in the direction of the current D, and a second pair of telescopic slides 52, 53 located downstream of the secondary plane C. Each telescopic slide 50 to 53 is located entirely under the main plane B. Each slide 50 to 53 connects one of the connecting elements 30 to 32 of the frame 14 to the channel 20. The telescopic slides 50 to 53 are further configured to allow a translation of the channel 20 relative to the frame 14 in a direction Z, called the displacement direction. The displacement direction Z is perpendicular to the main plane B. In addition, the slides 50 to 53 are configured to allow a translation of the channel 20 so that an upper face FS of the channel 20 remains under the main plane B. Generally, the telescopic slides 50 to 53 are configured to occupy a deployed position in which the telescopic slides 50 to 53 maintain the channel 20 in a submerged position, and a raised position in which the telescopic slides 50 to 53 maintain at least the upper face FS of the channel 20 in an emerged position.

[0059] Generally, the slides 50 to 53 maintain a rigidity of the unit 1 with respect to the appearance of a compensation torque linked to the lateral displacement of the Archimedes thrust in reaction to the rolling disturbances, and which are transmitted to the pivot connection 19 on the cylinder 18 of the channel 20. The telescopic slides 50 to 53 ensure the guidance of the channel 20 during the process of lowering / raising the channel 20.

[0060] According to one embodiment, a telescopic slide 50 to 53, and preferably each slide 50 to 53, comprises a lower part 70 fixed to the channel 20, preferably on an external face of the side fairings 22. For example, the lower part 70 is screwed vertically onto the external face of a side fairing 22 and forms a groove whose bottom is parallel to the median plane A. Each slide 50 to 53 further comprises an upper part 71 fixed to one of the connecting elements 30 to 32 and at least one intermediate part 72 movable in translation in the direction of movement Z relative to the lower and upper parts 70, 71. Each upper part 71 is, for example, screwed onto each connecting element 30 to 33, for example on internal faces of the connecting elements 30 to 33 facing the median plane A.Advantageously, as illustrated in Figures 9 and 10, the lower part 70 of at least one slide 50 to 53 comprises a first ball bearing 55 configured to guide the intermediate part 72 in movement in the direction of movement Z. In addition, the upper part 71 of a telescopic slide 50 to 53 may comprise a second ball bearing 56 configured to guide the intermediate part 72 in movement in the direction of movement Z. Using two ball bearings 55, 56, the deployment and lifting of the slides 50 to 53 are facilitated. The ball bearings 55, 56 reinforce the retention of the channel 20 to the frame 14. These ball bearings 55, 56 take up a crushing of the parts 70 to 72 of the slides in the direction perpendicular to the direction of movement Z. These bearings 55, 56 also make it possible to take up the torsional torques, associated with disturbances . yaw and yaw which are restored at the level of channel 20 and which are transmitted to the flotation organ 10.

[0061] Thus, the slides can be maintained, in the deployed position during operation, in order to rigidly maintain the frame 14 of the flotation member 10 with the channel 20, by which the power plant 1 is moored; or in the fully raised position, for maintenance phases for light repairs or when towing the power plant between a repair quay on the banks and the operating site.

[0062] All of the slides 50 to 53 are thus mounted on edge so that in the deployed position, they offer maximum resistance to maintain the rigidity of the unit 1 with respect to: a. of a torque linked to the longitudinal thrust on the flotation member 10 associated with the incident flow in nominal regime; and b. the appearance of clockwise or counterclockwise compensation torques linked to the upstream or downstream longitudinal displacement of the Archimedes thrust in reaction to pitch disturbances, torques transmitted to the pivot connection 19 on the cylinder 18 of the channel 20. The disturbances which are exerted on the flotation member 10 and which are transmitted to the channel 20 are also controlled.

[0063] Thus, the channel 20 can occupy a fully submerged position, as illustrated in FIGS. 1 and 7, under the flotation member 10 in operation, and a fully raised position to bring the channel 20 closer to the floor 15 in order to facilitate maintenance operations, and if necessary, facilitate the towing of the power plant 1 towards the banks so as to carry out more substantial maintenance operations, for example changing a turbine. In particular, when the channel 20 is fully raised, as illustrated in [Fig. 11], the upper face of the upper fairing 25 moves closer to the floor 15. An agent who works on the floor 15 can access the entire electrical system of the power plant 1, in particular the generators 48. In addition,

[0064] Advantageously, the central unit 1 comprises a lifting system 61 configured to move the channel 20 in translation. For example, the floor 15 comprises a main opening 60 and the lifting system 61 comprises a connecting element 62 connected to the channel 20 and passing through the main opening 60. The connecting element 62 may be connected at its lower end, preferably by at least three strands, attached to the upper plate 24 of the channel 20. The connecting element 62 may be a cable or a sling. The lifting system 61 may comprise a winch 63, manual or motorized, mounted on the floor 15, the upper end of the connecting element 62 being fixed to the winch 63.

[0065] Furthermore, the upper plate 24 of the channel 20 may comprise at least one secondary opening 95, 96 opening into the upper casing 25. This allows access to the interior of the upper casing 25, and the turbines 36 can be dismantled. It is thus possible to extract a generator 48, or repair it on site, or to work on the power electronics of the generators, or even on the electronic control unit. Furthermore, it is possible to work on the electrical connection, not shown for the sake of simplification, connecting the generators to the electrical network to recover the electrical energy produced by the power plant 1.

[0066] When the generator(s) 48 are housed within the upper casing 25, the secondary openings allow access to the generators to facilitate maintenance operations to be carried out on these generators, for example on the operating site or on a dedicated maintenance site located on the banks in order to be able to carry out more significant maintenance operations. To further facilitate access from the floor 15 to the interior of the upper casing 25, the secondary opening(s) 95, 96 are located in line with the main opening 60 in the direction of movement Z.

[0067] According to another advantage, the power plant 1 may comprise an anti-debris system 90, illustrated in figures 4, 5; 7, 8 and 11, to retain debris transported by the watercourse, and prevent the debris from coming into contact with the turbines 36. The anti-debris system makes it possible to protect the power plant 1, and in particular the turbines, in order to limit maintenance operations as much as possible. The anti-debris system comprises a lower grid 91 located upstream of the channel 20. The lower grid 91 has a downstream edge 100 mounted on the lower plate 26 of the channel 20 and an upstream edge 101 located upstream of the downstream edge 100. The anti-debris system 90 also comprises an upper plate 92 located upstream of the channel 20 and having a downstream edge 102 mounted on the upper plate 24 of the channel 20 and an upstream edge 103 located upstream of the downstream edge 102 of the upper grid 92.The upper grid 92 is further shaped so that its upstream edge 103 is configured to be in contact with the upstream edge 101 of the lower grid 91. For example, the upper grid 92 may comprise several bars 97. Advantageously, the upper grid 92 may comprise a middle bar 98 and the bars 97 are located on either side of the middle bar 98. In particular, the middle bar 98 has a “Y” shape that flares out towards the upstream edge 103 of the upper grid 92 so that the middle bar 98 forms a passage for the mooring line 80, as illustrated in [Fig. 8]. According to another advantage, the upper grid 92 is pivotally mounted about a transverse axis T contained in a secondary plane Pr parallel to the main plane B.Furthermore, the grid 92 is configured to be movable between a first position, in which the upstream edge 103 of the upper grid 92 is located below the secondary plane Pr, and a second position in which the upstream edge 103 of the upper grid 92 is located in or above. of the secondary plane Pr. In particular, in the first position, the grid 92 is configured to retain debris transported by the watercourse, and in the second position, the retained debris can be transported by the watercourse above the channel 20. Preferably, the anti-debris system 90 is configured so that when the upper grid occupies the first position, the upstream edge 103 of the upper grid is in contact with the upstream edge 101 of the lower grid 91. According to one advantage, the unit comprises a control device 200 configured to pivotally move the upper grid 92. The control device 200 may comprise a cylinder, preferably a pneumatic cylinder, and preferably a movable rod cylinder. The cylinder can be mounted, by its two ends, to the channel 20 and to the upper grid 92 in order to be able to move the upper grid 92 in rotation about the transverse axis T relative to the channel 20.Alternatively, the jack is electric, comprises a geared motor 210 contained in a cylindrical shell 212 pivotally mounted around an axis T2 mounted perpendicular to the median plane A. The geared motor 210 actuates a rod 211 of the jack. The rod 211 has one end pivotally mounted on the upper grid 92. The rod 211 is coaxial with the geared motor 210 which imposes a translational movement on the rod 211 and drives the upper grid 92 to pivot around the transverse T. .

[0068] Thus, by a screening operation, on the operating site of the power plant 1, the channel 20 is fully raised and the upper face 24 of the upper fairing 25 is brought closer to the floor 15 while being in the vicinity of the floor 15. The upper grid 92 is also placed in the second position. In this case, an agent who intervenes on the floor 15 can access the anti-debris system 90, in particular the upper grid 92, to put the upper grid 92 in the second position by pivoting it manually or by remote control.

[0069] The electronic control unit 201 may further be configured to control the control device 200 so as to bring the upper grid 92 into the second position at a determined frequency. For example, the electronic control unit 201 is configured to determine a power difference between a current electrical power supplied by said at least one generator 48 and a reference power corresponding to an electrical power supplied by said at least one generator in the absence of debris on the upper grid 92. The electronic control unit 201 may further be configured to calculate the determined frequency from the determined power difference.

[0070] To improve the protection of the power plant 1, the power plant 1 may comprise a deflector 300 in the shape of a “V” mounted on the flotation member 10, as illustrated in Figures 6 to 8, and 11. The deflector 300 is partially submerged, fixed on the upstream extension of the two longitudinal frames 16. The deflector 300 is intended to protect the flotation member 10 from large floating debris by sliding them on either side of the branches of the V. More particularly, the apex of the V is provided with a vertical cylinder 301, extending longitudinally perpendicular to the main plane B. The vertical cylinder 301 makes it possible to force trunks or branches impacting transversely on this apex to tilt to one side or the other of the deflector 300. Furthermore, the branches of the V comprise superimposed horizontal bars, or blades 302. A section along the median plane A of each of these horizontal blades is that of a symmetrical profile which promotes the yaw stability of the power plant 1.

[0071] As illustrated in [Fig.7], the mooring line 80, to stabilize the power plant 1 in a zero trim position against the current D, is subjected at the attachment point O to a tension R having a direction inclined at an angle Ph with a horizontal axis, parallel to the main plane B. The tension R is decomposed into a vertical component of intensity Iv = R * sin(Ph) (with Ph expressed in radians, R and Iv expressed in N). The intensity of the vertical component Iv is involved in the balance of the vertical forces applied to the power plant 1, namely the resultant Ba of the Archimedean forces and the overall weight Wl of the power plant 1. The tension R is decomposed into a horizontal component of intensity Ih = R * cos(Ph) (with Ph expressed in radians, R and Ih expressed in N).The intensity of the horizontal component Ih is involved in the balance of horizontal forces acting on the power plant 1, namely a drag force Df exerted on the two hulls 12 at a point CD located at the intersection of a first axis G and a central axis Va, and a force De of higher intensity. The first axis G is located at the intersection of the median plane A and a horizontal plane passing through the wetted surface of the two hulls 12. The central axis Va is located at the intersection of the median plane A and the secondary plane C (in [Fig.7], the secondary plane C is perpendicular to the plane of the sheet in [Fig.7]). The force De corresponds to the sum of the drag forces exerted on the channel 20. The drag forces exerted on the channel 20 correspond to the thrusts on the turbines, to the drags on the side fairings 22, on the upper 24 and lower 26 plates, and on the grids 91, 92 of the anti-debris system 90.

[0072] Advantageously, the power plant 1 is configured so that in nominal operation (i.e. in the zero trim position), the balance of the three vertical forces Ba, Wl, Iv acting in the median plane A on the power plant 1 is obtained, and the balance of the moments of these three forces Ba, Wl, Iv at the anchoring point O.

[0073] For example, the lateral fairings 22 of the channel 20 contain ballast in the vicinity of the secondary plane C symmetrically with respect to the median plane A so that the center of gravity CG of the unit is located on the central axis Va and below the anchoring point O.

[0074] For example, the frame 14 is positioned so that the center of the hull CB of the central unit 1 is located on the central axis Va. The center of the hull CB corresponds to the center of the volume of the fluid (and also the center of gravity of the fluid) displaced by the central unit 1. The center of the hull CB is also the point of application of the Archimedes thrust which makes the central unit 1 float.

[0075] For example, the degree of immersion of the channel 20 is sufficient so that the flow above the upper plate 24 of the channel 20 is stabilized from vertical hydrodynamic forces, and that consequently the lifts on the upper 25 and lower 27 casings are opposite and substantially equal in intensity.

[0076] Thus, the vertical forces can be balanced according to the balance Iv + W1 = Ba (where W1 is the overall weight expressed in N, and Ba the Archimedean forces expressed in N) and do not create any moment at the anchor point O.

[0077] Advantageously, the power plant 1 is configured so that in nominal operation (i.e. in the zero trim position), the balance of the three horizontal forces Ih, Df, De is exerted in the median plane A on the power plant 1, and the balance of the moments of these three forces Ih, Df, De at the anchoring point O.

[0078] For example, the length Lf of the hulls 12 of constant cross-section over at least 80% of its length, is sufficiently large so that the Froude number (dimensionless) FF = Vsmax / (Lf * g)1 / 2, where Lf whose unit is in meters, Vsmax is the maximum surface flow velocity conceivable for the given site of the watercourse (expressed in meters per second) and g the gravity (expressed in m / s2), is less than 0.4. In this case, the sum of the hydrodynamic drags on the hulls 12, is reduced substantially to a friction drag Df, the wave drag, source of longitudinal oscillations, being thus eliminated.

[0079] For example, the position of the anchor point O is fixed to equal the moduli of the opposing moments MDf and MDc generated respectively by the drag force Df exerted on the two hulls 12 and the drag force exerted on the channel 20. This positioning can be defined during the design from an average speed profile of the river. For example, the position of the attachment point O is fixed on the column 18 of the middle part 17 and the modulus of the moment MDf can then be optionally adjusted from the length of the connecting element 62, manually or controlled via the winch 63.

[0080] Thus, the horizontal forces can be balanced according to the balance Ih = Df + De and the moments MDf and MDc cancel each other out.

[0081] It is further possible to provide a method for maintaining the plant 1 which has just been described above. The method comprises the following main steps: - placing the floating hydroelectric power plant 1 in operating position on an operating site floating on the surface of a watercourse, and - a maintenance position comprising a translation of the channel 20 relative to the frame 14 in the direction of movement Z, so that an upper face FS of the channel 20 remains under the main plane B and occupies an emerged position.

[0082] The method may further comprise, before placing in operating position, an installation comprising: - towing the floating hydroelectric power station 1 on the surface of the watercourse, from a bank of the watercourse to the operating site, the towing comprising a translation of the channel 20 relative to the frame 14 in the direction of movement Z, so that an upper face FS of the channel 20 remains under the main plane B and occupies an emerged position; - mooring of the floating hydroelectric power station by connecting canal 20, via mooring line 80, to an anchoring system fixed to the bed or a bank of the watercourse, and - an operation, comprising a translation of the channel 20 relative to the frame 14 in the direction of movement Z, so that an upper face FS of the channel 20 remains under the main plane B and occupies an immersed position.

[0083] Furthermore, the method may comprise, after placing in maintenance position, a deinstallation comprising: - a disconnection of the mooring line 80 with the anchoring system; and - towing of the floating hydroelectric power station on the surface of the watercourse, from the operating site to a river bank.

Claims

Claims

1. Floating hydroelectric power station, intended to be partially submerged in a watercourse having a direction of flow, the floating hydroelectric power station comprising: a flotation member (10) comprising at least two hulls (12) coupled by a frame (14), the frame (14) comprising a flat part (15), called the floor, an upper face of the floor (15) extending in a main plane (B), and, for each hull (12), the frame (14) comprises a connecting element (30 to 33) connecting the hull (12) to the floor (15); characterized in that the plant comprises: a channel (20) having a convergent then divergent section in the direction of the current, the channel (20) comprising a pair of lateral fairings (22) connected by an upper plate (24) and a lower plate (26) parallel to the main plane (B); two turbines (36) mounted counter-rotating within the channel (20) respectively along two axes of rotation (X, X') together defining a secondary plane (C), perpendicular to the main plane (B), each turbine (36) having at least two blades (38) and being coupled to at least one generator (48) carried by the power plant; a mooring line (80) configured to connect the channel (20) to an anchoring system intended to be fixed on the bed or a bank of the watercourse; and a first pair of telescopic slides (50, 51) located upstream of the secondary plane (C) in the direction of the current, and a second pair of telescopic slides (52, 53) located downstream of the secondary plane (C), each telescopic slide (50 to 53) being located entirely under the main plane (B) and connecting one of the connecting elements (30 to 33) of the frame (14) to the channel (20), the telescopic slides being configured to allow a translation of the channel (20) relative to the frame (14) in a direction (Z), called displacement, perpendicular to the main plane (B) and so that an upper face (FS) of the channel (20) remains under the main plane (B).

2. A power station according to claim 1, wherein the floor (15) comprises a main opening (60) and the power station comprises a lifting system (61) comprising a connecting element (62) connected to the channel (20) and passing through the main opening (60), the lifting system being configured to move the channel (20) in translation in the direction of movement (Z).

3. A power plant according to any preceding claim, wherein the telescopic slides (50 to 53) are configured to occupy a deployed position in which the telescopic slides (50 to 53) maintain the channel (20) in a submerged position and a raised position in which the telescopic slides (50 to 53) maintain at least the upper face of the channel (20) in an emerged position.

4. A unit according to any one of the preceding claims, wherein each telescopic slide (50 to 53) comprises a lower part (70) fixed to the channel (20), an upper part (71) fixed to one of the connecting elements (30 to 32) and at least one intermediate part (72) movable in translation in the direction of movement (Z) relative to the lower and upper parts (70, 71).

5. Power plant according to the preceding claim, in which the lower part (70) of at least one slide comprises a ball bearing configured to guide said at least one intermediate part (72) in movement in the direction of movement (Z).

6. A power plant according to claim 2, wherein the channel (20) comprises an upper casing (25) mounted on the upper plate (24) and a lower casing (27) mounted on the lower plate (26), at least one of the upper (25) and lower (27) casings being configured to house said at least one generator (48).

7. Power plant according to the preceding claim, in which said at least one generator (48) is housed within the upper casing (25).

8. Power plant according to any one of claims 6 and 7, in which the upper plate (24) of the channel (20) comprises at least one secondary opening (95, 96) opening into the upper casing (25).

9. Power plant according to the preceding claim, in which said at least one secondary opening (95, 96) is located in line with the opening main (60) according to the direction of movement (Z).

10. A plant according to any preceding claim, comprising an anti-debris system (90) comprising a lower grid (91) located upstream of the channel (20) and having a downstream edge (100) mounted on the lower plate (26) of the channel (20) and an upstream edge (101) located upstream of the downstream edge (100), and an upper plate (92) located upstream of the channel (20) and having a downstream edge (102) mounted on the upper plate (24) of the channel (20) and an upstream edge (103) located upstream of the downstream edge (102) of the upper grid (92), the upper grid (92) being shaped such that its upstream edge (103) is configured to be in contact with the upstream edge (101) of the lower grid (91).

11. Power plant according to the preceding claim, in which the upper grid (92) comprises several bars (97) located on either side of a middle bar (98) having a “Y” shape widening towards the upstream edge (103) of the upper grid (92) so that the middle bar (98) forms a passage for the mooring line (80).

12. A plant according to any one of claims 10 and 11, wherein the upper grid (92) is pivotally mounted about a transverse axis (T) contained in a secondary plane (Pr) parallel to the main plane (B), between a first position in which the upstream edge (103) of the upper grid (92) is located below the secondary plane (Pr) so that the upper grid (92) can retain debris carried by the watercourse, and a second position in which the upstream edge (103) of the upper grid (92) is located in or above the secondary plane (Pr) so that the retained debris can be transported by the watercourse above the channel (20).

13. Power plant according to the preceding claim, comprising a control device (200) configured to move the upper grid (92) in pivoting around the transverse axis (T).

14. Power station according to the preceding claim, in which the control device (200) comprises a cylinder, preferably a pneumatic cylinder, and preferentially a cylinder with a movable rod.

15. A power plant according to any one of claims 13 and 14, comprising an electronic control unit (201) configured to control the control device (200) so as to bring the upper grid (92) into the second position at a determined frequency.

16. Power plant according to the preceding claim, in which the unit of electronic control unit (201) is configured to determine a power difference between a current electrical power supplied by said at least one generator (48) and a reference power corresponding to an electrical power supplied by said at least one generator in the absence of debris on the upper grid (92), the electronic control unit (201) being further configured to calculate the frequency determined from the power difference.

17. Method for maintaining a floating hydroelectric power station according to any one of the preceding claims, comprising: - placing the floating hydroelectric power station in an operating position on an operating site floating on the surface of a watercourse, and - placing it in a maintenance position comprising a translation of the channel (20) relative to the frame (14) in the direction of movement (Z), so that an upper face (FS) of the channel (20) remains under the main plane (B) and occupies an emerged position.

18. Method according to the preceding claim, comprising, before placing in the operating position, an installation comprising: • towing the floating hydroelectric power station on the surface of the watercourse, from a bank of the watercourse towards the operating site, the towing comprising a translation of the channel (20) relative to the frame (14) in the direction of movement (Z), so that an upper face (FS) of the channel (20) remains under the main plane (B) and occupies an emerged position; • mooring of the floating hydroelectric power station by connecting the channel (20), by the mooring line (80), to an anchoring system fixed on the bed or a bank of the watercourse, and • putting into operation, comprising a translation of the channel (20) relative to the frame (14) in the direction of movement (Z), so that an upper face (FS) of the channel (20) remains under the main plane (B) and occupies a submerged position.

19. Method according to any one of claims 17 and 18, comprising, after placing in the maintenance position, a deinstallation comprising: • a disconnection of the mooring line (80) with the anchoring system; and • a towing of the floating hydroelectric power station on the surface of the watercourse, from the operating site towards a bank of the watercourse.

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