KR20070085927A - Hydrodynamic drive train for energy converters that use ocean currents - Google Patents

Abstract

The invention relates to an energy generation system for obtaining electric energy from an ocean current. Said system comprises a drive train comprising an input shaft and an output shaft, the input shaft being driven at least indirectly by a water turbine and the output shaft at least indirectly driving an electric generator, which is connected to an electric network. The electric network has an essentially constant network frequency and the drive train comprises an output branching gear with a first output branch and at least one second output branch. The first output branch and the second output branch are interconnected by means of the output branching gear and a hydrodynamic component.

Description

HYDRODYNAMIC DRIVE TRAIN FOR ENERGY CONVERTERS THAT USE OCEAN CURRENTS}

The present invention relates to an apparatus and a method for generating electrical energy from an ocean current, in which the generated electrical energy is actually supplied to an electrical network with a substantially constant network frequency.

Ocean currents offer great potential to obtain electrical energy without releasing air pollutants in the event of energy generation. Such currents exist permanently (an example of this is currents occurring in the bay) or is caused by high and low tide. Currents caused by high and low tide are particularly strong regions of tidal flats and areas where unique currents are caused by geographic features such as narrow perfusion areas or unusually formed bay areas. Related to If there are special conditions, rough waves can be utilized to drive the submerged turbo engine. Such conditions can be created by artificial measures, such as current inflow tanks, and by such measures, the dynamic energy inherent in the waves can be utilized.

One of the features that appear when driving a water turbine using current flow can be a power yield that can vary over time. This continuous change over time also occurs in permanent flow zones. This condition is surprising first of all, but the fact that the measurement results of turbo engines with typical submersion depths of tens of meters in the bay, for example, can vary over time for such energy generation systems. The power yield must be taken into account. The cause is, on the one hand, wave movements resulting from weather effects and such weather effects. On the other hand, the measurement results demonstrated the occurrence of turbulence in the ocean currents. Turbulence appears not only in tidal flows but also in permanent flow patterns in the oceans, particularly in the depth zones of up to 50 meters provided for energy generation.

In the mechanical energy conversion process, which converts the dynamic energy of a fluid medium into the dynamic energy of a hydro turbine, attention should be paid to the characteristics and dynamics in addition to the fluctuations of the dynamic energy from the ocean currents over time. Should be. Thus, there is a system specific characteristic for power conversion in the input shaft, which assigns an optimum rotational speed / torque ratio corresponding to a high speed drive for power conversion to a specific flow velocity of the current, and the optimum The rotational speed / torque ratio of is again dependent on the structure and shape of the power converter.

Such power conversion characteristics also exist in other turbo engines such as wind turbines. However, turbo engines for obtaining energy from currents are different from wind systems, because of the higher density of the flow medium, high torque acts on the power converter, which is why the power converter is for example driven chain and electrical. This is because they are smaller in size compared to additional elements of energy generating systems such as generators and mechanical support structures. From this fact, in order to improve the whole system from the flow technical point of view, the necessity to form the drive chain and the electric machine of the energy generating system as small as possible is derived. However, when it comes to reducing the overall size associated with electrical generators used in energy generating systems, there is a barrier that power converters driven by current flow typically circulate at relatively low rotational speeds of less than 20 U / min. If no gear is connected between the water turbine and the electrical generator, the overall circulation is inevitably due to the low circulation speed of the electric machine.

Additional requirements arise when the energy generating system driven by the current flow supplies electrical energy to an electric combined network having a fixed network frequency. Starting from the fact that the power converter of the energy generating system, i.e., the speed of the water turbine is variable, likewise the electric generator with variable speed operates creates the necessity of using a frequency converter to supply energy to the electric complex network. do. The frequency converter excites the electrical generator to the required frequency and compensates for the difference to the existing network frequency. However, this approach is difficult because, in the case of turbo engines, the peculiarities of the power conversion characteristics can only be insufficiently represented by the frequency converter. In this case, a correspondingly high cost is required to achieve a suitable network power supply quality, especially with regard to the formation of harmonic vibration loads and reactive power.

Instead, as an alternative method, if the water turbine is formed such that, for example, by adjusting the blade wheel, the rotational constant of the power converter is ensured, the electric generator driven at least indirectly by the power converter is also fixed. Can be formed. As such, an energy generating system having a fixed rotation speed can be connected to an electric hybrid network in a simple manner due to a principle slip phenomenon when using an asynchronous generator. However, a disadvantage of this case is that the energy efficiency is lowered as a result of setting the blade wheel position for keeping the speed of the power converter constant. In other words, the power converter cannot obtain the maximum energy from the current.

The problem to be solved by the present invention is to provide an apparatus for generating electrical energy from an ocean current and a method for operating the apparatus, in which the aforementioned disadvantages are overcome. In particular, such an energy generating system should be capable of operating in a partial load region where the speed of the power converter is variable while the speed of the electrical generator is constant. The energy generation system should also be able to implement additional operating states. In particular, in order to prevent the occurrence of cavitation and to protect the fish from harmful circulation speeds, the speed of the power converter should be adjustable above the speed threshold. In the power range, where the speed is constant, shock reduction and short-term energy supply to absorb load shocks and analyze power peaks must be possible. The energy generation system should also be able to implement momentary adjustments in the entire load area and unusual operating states such as, for example, shutdown and load shedding.

In order to solve the above problem, the inventors first recognize that in order to be able to form an electric generator small enough in size compared to a water turbine, a water turbine driven by sea current must be connected to an electric generator running at high speed through a gear. Was done. In addition, according to the invention, the coupling between the water turbine and the electrical generator is made by a drive chain comprising a hydraulic gear. The hydraulic gear is used on the one hand for the speed shift, and on the other hand, to make the speed of the electric generator constant and at the same time to realize the possibility of variable speed of the water turbine. Such content can be realized by adjusting and controlling at least one hydraulic element inside the hydraulic gear, in which case it is particularly desirable to form the hydraulic gear as a power branch gear.

According to one preferred embodiment of the invention, the drive chain comprises an overlapping gear, for example a satellite gear and at least one second power branch for diverting power to the first power branch. Inside the first power branch, a shaft circulating at high speed is disposed to drive the electric generator. The second power branch is at least indirectly coupled to the first power branch via hydraulic elements, for example a hydraulic transducer, a hydraulic coupling or a trilock transducer. By adjusting and controlling the power flow through the hydraulic elements and by adjusting and controlling the degree of coupling between the first and second power branches, the possibility of varying the rotational speed of the power converter and with it the maximum energy from the current At the same time, the rotation speed of the electric generator can be kept constant.

During operation of the water turbine according to the prior art, the electric generator is first accelerated until it reaches its target rotational speed, and synchronization with the electric network can be executed. During normal operation achieved then, the network frequency is provided to the electrical generator, so that the first power branch is provided with a target rotational speed depending on the number of polarities. Since the conventional rotational speed of the electric generator is for example 1500 U / min, electric generators of small structural size can be used as a result. In addition, when the rotational speed is high as described above, the effective operation of the hydraulic elements assigned to the second power branch, which is at least indirectly connected to the first power branch on the shaft of the first power branch, is also possible. Due to the power flow between the first power branch and the second power branch regulated and controlled by hydraulic elements, a water turbine having a rotational speed that is optimal for power conversion can be provided.

If a hydraulically regulated converter is used as hydraulic elements for connecting between a first power branch and a second power branch, the characteristics of the regulated converter in relation to the speed- / power- and speed- / moment ratios are dependent on the power. Corresponds to the characteristics of the transducer. This fact can be utilized to realize the automatic adjustment effect. The drive chain with the regulating transducer may be guided when the water turbine is optimal for the output in relation to the rotational speed at a substantially constant position of the guide wheel of the regulating transducer and at the same time the circulation speed of the electric generator is constant. It can be designed to be. According to this design scheme, when the regulating converter is used in the power branched drive chain of the energy generating system according to the present invention, there is no requirement for setting the rotation speed of the water turbine that is optimal for the output.

In order to avoid the formation of cavitation bubbles, the maximum speed of the water turbine should not be exceeded. In addition, as the speed of the water turbine increases, the risk of damage to marine life also increases. As such, from the predetermined rotational speed threshold depending on the shape and size of the water turbine and the flow direction and flow velocity in this case, the water turbine corresponds to the desired shape or to the preferred method of operation. The circulation speed is limited. Depending on the design approach, one of the two factors is crucial when determining the upper rotational speed threshold for the water turbine of the energy generating system.

In the energy generation system according to the invention, the speed guide for limiting the speed of the water turbine is made by means of an adjustment scheme selected for the hydraulic elements inside the hydraulic gear. If, for example, one regulating converter is used and the drive chain of the energy generating system according to the invention is preferably formed in a power branched state, the power transfer from the first power branch to the second power branch is guided by the regulation converter. This can be done by varying the setting of the wheel. For this purpose, the guide wheel state is generally stopped, which guides the water turbine to an optimal state for output.

When the power consumption is the best, i.e., when the power consumption is along a parabolic line, the threshold rotational speed is also assigned a power consumption threshold. In the event of a change in input power above the power threshold, it is necessary to adjust the hydraulic elements inside the hydraulic gear to maintain the rotational constant of the water turbine. The shape of the water turbine speed detection sensor required for such adjustment and the regulator acting on the hydraulic elements can be realized within the framework of expert knowledge.

One particular advantage of the energy generation system according to the invention with hydraulic gears is that the vibrations at the power input and in particular the load fluctuations which are replaced quickly over time are attenuated for the operating state of the water turbine with the speed adjusted. And that the energy input of the water turbine can be used to accelerate the water turbine in a short time and with it as a short time energy store. The reason for this characteristic is that a specific work point is determined by adjusting or controlling the setting contents of the hydraulic elements. In the case where a predetermined speed interval exists, the variation of the water turbine speed can be as much as the working point. To this end a fluctuation range of ± 10% and preferably ± 5% and particularly preferably ± 3% is allowed.

If a load impact on the water turbine occurs due to the turbulent effect, the speed will rise in a certain range, so that additional power provided for a short time is introduced into the system. This process has the purpose of utilizing the added power on the one hand, and on the other hand, to alleviate the load impact so that the load shock absorbing action by the mechanical support structure is no longer needed. This feature preferably reduces the torque impact inside the drive chain, thereby affecting the useful life of the energy generating system.

In the partial load region operated along the parabola in a state where the energy generating system according to the invention is optimal for power and preferably in a speed limited state or in a speed guided state from a specific speed threshold, Connected. A feature of the full load region is that maximum torque is achieved on the power converter. Above the torque threshold is a torque adjustment for the water turbine, in which case for the energy generation system according to the invention an additional limit is placed on the power dissipated by the water turbine in addition to adjusting the hydraulic elements inside the drive chain. Adjusting members are used. In one preferred embodiment, the power limitation is achieved by changing the angle of the blade wheel of the water turbine, but this power limitation process has a slow reaction time, while in the case of the adjustment of the hydraulic elements, in the case of the regulating converter, The regulation limits the power for a short time for the electrical generator. Thus, the angle adjustment system of the blade wheel of the water turbine can be connected for a short time with the adjustment transducer capable of high speed adjustment.

If a hydraulic coupling is used as a hydraulic element instead of a regulating converter, no automatic regulation for guiding the water turbine to the power optimum can be realized at all. In such a case, in order to guide the rotational speed of the water turbine along the parabola in the power optimum state in the partial load region, the setting contents of the hydraulic coupling must be actively adjusted. However, in the case of preferably using hydraulic coupling instead of regulating transducers, an increase in the power efficiency of the drive chain is achieved, especially under full load conditions. If tree lock transducers are used as alternative hydraulic elements, advantages also arise in terms of efficiency over hydrostatically controlled transducers in certain power regions or operating stages.

The invention is explained in detail below with reference to the drawings.

1 is a schematic diagram of an energy generation system according to the present invention,

2 is a schematic diagram illustrating one preferred embodiment of a drive chain of an energy generation system with first and second power branches,

3 is a rotational speed / torque diagram of three operating regions of an energy generating installation according to the invention,

4 is a view showing the automatic adjustment effect when using a hydraulically adjustable transducer in the drive chain to realize a power optimum speed guide in the partial load region,

FIG. 5 is a view showing the adjustment state of the guide wheel of the hydraulically adjusted transducer when conversion is made between the individual operating regions of FIG. 3, FIG.

6 shows short-term energy storage and load impact reduction of an energy generating system according to the invention in a speed adjusted region,

Figure 7 is a schematic diagram showing three adjustment planes for operating the energy generation system according to the present invention.

1 schematically shows an energy generation system according to the invention. The electrical generator 11 connected to the electrical network 60 is at least indirectly driven by the water turbine 3. The water turbine 3 may be formed within the framework of those skilled in the art. For example, a propeller structure with two or multiple blades can be selected. Additional structures may be provided around the water turbine that are used for protection purposes or to guide the flow. According to the invention, a hydraulic drive chain 1 is used between the water turbine 3 and the electric generator 11. In the present invention, the hydraulic drive chain 1 means a power branched drive chain comprising a first power branch 7 and at least one second power branch 18. A power branch gear is used to branch the power provided to the hydraulic drive chain on the drive side, which may for example be a planetary wheel set. On the driven side of the power branch gear 5, a coupling is made between the first power branch 7 and the second power branch 18 by hydraulic elements assigned to the second power branch, so that It is possible to provide different circulation speeds from a constant circulation speed of the electrical generator 11.

The energy generation system may also include optional elements. Such optional elements are additional gears connected before or after the hydraulic drive chain. In FIG. 1, the gear stage 4 formed as a planetary wheel gear is used for the first shift of the water turbine rotational speed. In addition, a power transmission member 50 may be provided between the hydraulic drive chain 1 and the electrical generator 11 which may include a clutch and / or a brake. The clutch and brake may also be present between the additional gear 4 and the hydraulic drive chain 1.

1 does not show the mechanical support structure for the energy generation system in detail. An embodiment in which the elements shown in FIG. 1 are integrated as a constituent unit and surrounded by a watertight housing, whereby the entire constituent unit can be locked is preferred. The building unit can be submerged along the support structure to a desired depth for energy gain.

2 shows one preferred embodiment of the hydraulic drive chain 1 of the energy generation system according to the invention. In detail, the input shaft 2 of the hydraulic drive chain is at least indirectly connected to the water turbine 3 of the wind power system according to the invention. In this case a gear 4 with a constant speed ratio is arranged between the rotor 3 of the wind machine and the input shaft 2. In the embodiment shown in FIG. 2, a satellite wheel gear is used as the power branch gear of the drive chain 1, in which case the input shaft 2 is connected to the satellite wheel carrier 6. Inside the power branch gear 5 there are two power branches, the first power branch 7 transmitting power via a sun wheel 9 of the satellite wheel gear to the output shaft 10 of the drive chain. To guide. The output shaft 10 drives the electrical generator 11 at least indirectly and is in operative coupling with the hydraulically adjusted transducer 12. For this purpose the output shaft 10 is at least indirectly connected to the pump wheel 13 of the hydraulically adjusted transducer 12. A guide wheel with an adjusting blade is used as the reaction member 15 inside the hydraulic transducer 12, by which the influence of the power on the turbine wheel 14 can be adjusted. Through the turbine wheel 14 again the power guided through the second rigid satellite wheel set 16 adversely affects and acts on the outer wheel 17 of the power branch gear 5 to affect the speed ratio. Crazy This is the function of the second power branch 18 of the power branch gear which is used for the reverse action of power.

Three main operating areas are distinguished for the operation of the energy generating system according to the invention. This division is schematically illustrated in FIG. 3. The power consumed by the water turbine in this embodiment and expressed in any unit is likewise dependent on the rotational speed of the water turbine in any unit.

In the area marked I, the energy generation system is operated at partial load. The region starts from a predetermined speed and ends at a predetermined speed threshold D _max . The curve of the operating region I shown in FIG. 3 is a target curve showing the speed guide in a state that is optimal for the power of the water turbine 3. According to him a certain power input is assigned the optimum rotational speed of the water turbine 3. If the water turbine 3 rotates at a lower or higher rotational speed than the optimum rotational speed, it is impossible to obtain the best current current power from the energy generating system at all. The concept of a speed guide along the parabola is also used in this application for power optimum speed guide in the operating region I.

For the energy generation system according to the invention an electric generator 11 having a constant, preferably high speed, rotational speed is used. The rotational speed of the synchronous generators coupled to the network frequency is supported by the electric composite network 60. The same applies to the asynchronous generator in a sufficient range when the asynchronous generator is operated in a steeply moving linear region. Starting from such a constant rotation of the electrical generator 11, control of the actuation coupling between the drive chains through the hydraulic elements, ie the first power branch 7 and the second power branch 18 of the power flow, and / Alternatively, by adjusting the input rotational speed of the drive chain and the rotational speed of the water turbine 3, the water turbine is always circulated at the optimal rotational speed.

If the hydraulically adjustable transducer 12 is used as a hydraulic element, the adjustment in its original meaning cannot be used for power optimum rotational speed guide of the water turbine 3, but rather a system-specific automatic adjustment effect will be used. Can be. This is illustrated in FIG. 4. In the figure curve E is the power consumed by the wind rotor, curve F is the power at the sun wheel 9, curve G is the power transmitted from the drive chain and curve H is through the first power branch 18 It indicates the power flowing back from the hydraulic transducer 12 toward the power branch gear 5. Further details of the setting of the guide wheel 15 of the hydraulically adjusted transducer are shown. As can be seen from the figures, when the optimum power consumption is achieved along the parabola, which can be represented by the characteristics of the drive chain 1, the hydraulic transducer 12 is actually the same throughout the entire partial load region shown. Can be operated with guide wheels. This setting is referred to below as the adjusted setting of the hydraulic transducer 12. In other words, no adjustment of the guide wheel is necessary at all in order to reach the optimum water turbine speed which is variable at the same time as the starting speed constant of the drive chain for charging the electric generator 11. In this case, reference is made to the fact that the inclination of the parabola characterizing the power consumption can be adjusted in relation to the transmission ratio design of the elements of the power branch gear and the design of the hydraulic transducer. Such a feature of the drive chain 1 according to the invention is referred to below as automatic adjustment.

Optimally for power under partial load conditions of currents, the operating region (I) from which the kinetic energy can be obtained by the power consumption of the energy generating system according to the invention is a constant rotational speed up to the full load region along the power parabola. Can be guided by. However, in such operation guides, the rotational threshold (D _max ) is typically exceeded from a certain power input, which should be considered for the purpose of preventing cavitation or for the protection of fish. Thus, from the threshold rotational speed D _max , the operating region I is preferably interrupted and passed over to the operating region II, wherein the operating region II is characterized in that the water turbine speed is kept constant.

In order to form a drive chain 1 with a hydraulically adjustable transducer 12 as a hydraulic element, a conversion process between the individual operating regions is shown in FIG. 5. In the operating region I, where the rotational speed is guided with power optimum, the operation is carried out at 25% of the adjustment distance, in the present case, in the same guide wheel state, for the purpose of the automatic adjustment effect. In the case of a change from the operating area I to the rotational speed limited operating area II, the optimum guide wheel condition is interrupted and the guide wheel of the hydraulically adjustable transducer 12 adjusts as power inflows from the water turbine 3. By doing so, the water turbine rotational speed is kept substantially constant, but only the torque consumed by the water turbine 3 and the power consumed with it vary. In one embodiment of the invention, in the operating region II a specific speed waveform, preferably a particularly steep speed waveform, may be selected instead of the actual speed threshold. The characteristic of the operating area II is that the power optimum speed guide is interrupted.

Also shown in FIG. 5 is a process in which the speed limited operating region II is converted to a torque limited operating region III. In this case the control and / or adjustment to bring about the speed constant is stopped above the critical moment of the wind turbine 3. In order to prevent an undesired increase in power generation of the water turbine 3 in the operating region III, for example, further measures such as changing the blade wheel state of the water turbine 3 or adjusting the corresponding guide device. These limits the inflow of power by the water turbine 3 and prevents further rotational speed increases to limit the torque. In order to adjust the blade wheel state of the water turbine 3 at the power increase in the operating region III, first, the guide wheel state of the hydraulically adjusted transducer 12 is changed to prevent the moment rise in a short time by the drive chain. This state raises the rotation speed of the water turbine for a short time, but this rotation increase is limited by the blade wheel adjustment of the water turbine 3 made in the second step. Such details are not shown in detail in FIG. 5.

FIG. 6 shows the case of the operating region II in which the predetermined target rotational speed of the water turbine 3 is shown above the specific rotational speed threshold region due to the poor adjustment of the hydraulic regulating converter 12. The curve shown indicates different guide wheel conditions (H = 25% to 100% adjustment distance). In this case the hydraulically adjusted transducer was adjusted with guide wheels with an H = 25% adjustment. It can be seen from FIG. 6 that different work points can be selected due to poor adjustment of the hydraulic adjustment transducer 12. This fact opens the possibility of adjusting the rotation speed of the water turbine 3. In the simplest case the speed is limited, so that the working points for the desired speed of the water turbine 3 can be further adjusted along a curve depending on the torque consumed by the water turbine 3. This makes it possible in particular to adapt the flexibility of the drive chain to the limits for full load operation.

A parabolic power consumption characteristic is again obtained around the working point of the operating region II, which is adjusted by the poor adjustment of the hydraulically adjusted transducer, which manifests itself in the case of fluctuations in the flow velocity. This situation is illustrated in FIG. 6. It should be noted in this case that the adjustment of a particular work point can be made slowly, ie in the seconds to minutes range and depends on the average flow rate. The possible fluctuations around the work point, which are each compensated by the automatic control through the system features of the drive chain which appear in the case of using the hydraulic transducer 12, are the effects for a short time formed by vibration. The fluctuation range should not exceed ± 30%, preferably ± 10% and particularly preferably ± 5% of the preferred speed at the work point.

In addition to the operating areas I to III described above, additional operating states can also occur, ie start-up or switch-off of the energy generating system, synchronization of the network frequency with the electrical generator, load disconnection, emergency stop or test- or preventive action, for example. Special operating conditions can occur. In order to implement different operating areas and operating states, it is preferable that the regulating device and the control device for the energy generating system according to the invention are formed in the form of a hierarchical structure divided into three regulating planes. Such a shape is schematically illustrated in FIG. 7. The first conditioning plane is the energy generating system itself. In this case, the shape of the drive chain of the energy generating system with the hydraulically adjustable transducer as the hydraulic element is preferred, which induces automatic regulation. Likewise alternative hydraulic elements, such as, for example, hydraulic coupling or tri-lock converters, can be considered in terms of efficiency. For this case, the system-specific automatic regulation must be replaced by an active regulation to guide the rotation of the water turbine. The first adjustment plane is superimposed by a second adjustment plane comprising a regulator for the adjustment of the blade wheel and for the adjustment of the hydraulic elements and a regulator for the power electronics of the generator. In this plane, a comparison process between the target value and the actual value is performed for each regulator described above, and a corresponding adjustment signal is output therefrom.

According to the invention, not all regulators of the second adjusting plane respond to all operating regions or operating states. Control of regulator operation and control of regulator weighting or switching between individual regulators is caused by the third adjustment plane. The third adjustment plane not only selects the size to be adjusted according to the operating state or the operating area, but also makes it possible, for example, to use different adjusters or different adjuster settings for the same size of blade wheel position. As such, the adjustment characteristics and the speed of adjustment can be adapted to each particular situation. In addition, the third adjustment plane serving as the higher control plane allows the setting of the regulator target value and the selected work point.

Claims (15)

An energy generating system for obtaining electrical energy from currents, 1.1 a drive chain 1 having an input shaft 2 and an output shaft 10; 1.2 the input shaft 2 is at least indirectly driven by the water turbine 3; 1.3 The output shaft 10 at least indirectly drives the electrical generator 11, which is connected to an electrical network 60, in which case the electrical network 60 is in fact a constant network frequency. Have it; 1.4 the drive chain (1) comprises a power branch gear (5) with a first power branch (7) and at least one second power branch (18); 1.5 An energy generation system in which the first power branch (7) and the second power branch (18) are coupled to each other via a power branch gear (5) and hydraulic elements (12). The method of claim 1, The hydraulic elements (12) are characterized in that the hydraulically regulating transducer, the hydraulic coupling or the tree lock transducer. The method of claim 2 or 3, Energy generating system, characterized in that the hydraulic elements (12) are arranged on the driven side of the power branch gear (5). The method according to any one of claims 1 to 3, Energy generation system, characterized in that the hydraulic elements (12) are at least indirectly connected to the drive shaft of the electric generator (11). The method according to any one of claims 1 to 4, The energy generator system, characterized in that the electric generator (11) is formed as a generator that travels at high speed. The method according to any one of claims 1 to 5, An energy generating system, characterized in that a transmission gear (4) is arranged between the input shaft (2) of the drive chain and the water turbine (3). The method according to any one of claims 1 to 6, An energy generating system, characterized in that an additional stand gear (16) is provided inside the first power branch (7) and / or the second power branch (18) to adapt the rotational speed. The method according to any one of claims 1 to 7, The energy generation system, characterized in that the water turbine (3), the drive chain (1) and the electric generator (11) are formed as constituent units which can be submerged in water. A method for operating an energy generation system according to any of claims 1 to 8, Method of operation of an energy generation system, characterized in that the energy generation system exhibits an optimum number of revolutions in power in the partial load region of the water turbine (3). 10. A method for operating an energy generating system according to any of claims 1 to 9, And the rotation speed of the water turbine is guided along a target curve above the rotation speed threshold value (D _max ). 10. A method for operating an energy generation system according to claim 9, And the rotational speed is kept substantially constant. 12. A method for operating an energy generation system according to any of claims 1 to 10, The method of operating an energy generating system, characterized in that during the load impact the rotational speed can be varied at predetermined rotational intervals. A method for operating an energy generation system according to any of claims 1 to 10, Above the maximum torque of the water turbine (3) the method of operating an energy generating system is characterized in that the moment transmitted to the electric generator (11) is limited by the adjustment of the hydraulic elements (12). A method for operating an energy generation system according to claim 13, Above the maximum torque of the water turbine (3) the method of operating an energy generating system is characterized in that the power obtained from the current current by the water turbine (3) is limited. A method for operating an energy generating system according to claim 14, The power limiting process is performed by adjusting the blade wheel of the water turbine (3) and / or by adjusting the guide device (15) assigned to the water turbine (3).

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