DE102022106633A1 - Composite of an electrical network, a power plant and a storage power plant as well as methods for balancing the fluctuating power supply of the power plant - Google Patents

Abstract

The invention relates to a network consisting of an electrical network (1), at least one power plant (2) and at least one storage power plant (3) for balancing a fluctuating power supply from the power plant (2) to the electrical network (1), wherein the storage power plant (3) at least one electromechanical converter (4) and the electromechanical converter (4) has a rotating electrical machine (5) and at least one rotational inertia storage (7) with a rotary flywheel (8) and the electrical machine (5), the rotary flywheel (8) and a other devices are connected to each other. Here, the electrical machine (5) is a first rotating electrical machine (5) and the further device is a component of the electromechanical converter (4), the device being a further, second rotating electrical machine (6) or as a magnetic torque clutch with a Adjusting device is designed to influence a mechanical load coupling. The invention also relates to a method for balancing the fluctuating power provision, wherein in load states of the electrical network (1) and/or operating states of the storage power plant (3), power is provided between the electrical network (1) and the storage power plant (3) via the first electrical machine (5), the second electrical machine (6) or both electrical machines (5, 6).

Description

The invention relates to a network consisting of an electrical network for the transmission and distribution of electrical energy and at least one power plant, the power plant having a fluctuating power feed into the electrical network and therefore no uniform energy output can be guaranteed during regular operation of the power plant, and at least one storage power plant to compensate for the fluctuating power feed of the power plant, wherein the storage power plant has at least one electromechanical converter and the electromechanical converter has a rotating electrical machine and at least one rotational inertia storage with a rotary flywheel and the electric machine, the rotary flywheel and a further device are connected to one another.

In addition, the invention relates to a method for compensating for a fluctuating provision of electrical power in the electrical network of the network caused by the at least one power plant.

The supply of energy into electrical networks, which is generated in particular from renewable energy sources such as wind and sun, is constantly increasing. Due to these energy sources, which generally only act intermittently, and the resulting discontinuous supply of energy, there is an increased load on the electrical networks. This potentially increases the probability of under- or over-feeding of an electrical network, whereby any energy deficit or excess energy must be compensated for using positive or negative control energy or control power.

Different methods can be used to compensate. This is how the genre describes EP 1 485 978 A2 in one embodiment, an electrical island network which is fed by at least one wind turbine. Parallel to the output of a grid-commutated inverter connected to the wind turbine via a DC intermediate circuit, a synchronous generator acting as a network generator is also connected, which is fed from the island network during engine operation. In one embodiment, a flywheel is also coupled to the synchronous generator, so that excess energy can be stored during engine operation and fed back into the island network in the event of an energy deficit in generator operation of the synchronous generator. An internal combustion engine can also be connected to the synchronous generator via an electromagnetic clutch and this can be operated in generator mode. In this way, fluctuations in the provision of electrical energy by the wind turbine can be at least partially compensated.

In addition to the compensation of electrical variables, such as electrical energy, devices are known from the prior art with which differences in other physical variables, for example mechanical variables, can also be compensated for.

The DE 198 11 966 A1 are in this sense e.g. B. an induction clutch and an induction brake can be found. Instead of a sliding ring current collector, which supplies energy to an electromagnet arranged on a first shaft, a magnet wheel made of permanent magnets and a first short-circuit winding are designed on a first shaft of the induction clutch. On a second shaft, only a short-circuit winding is designed, into which a current generating a magnetic field is induced when the first shaft rotates. As a result of the interaction of the magnetic fields of the first and second shafts, the second shaft is also set to rotate. By opening or closing the second short-circuit winding, the induction clutch can be engaged or disengaged and, in particular, the transmitted torque can be influenced by changing the distance between the shafts.

From the US 7,535,143 B2 is a further induction clutch for coupling an input shaft to an output shaft and in particular for coupling an internal combustion engine to the wheels of a motor vehicle. An electrical machine is connected to the input and output shafts. This solution also aims to avoid current consumption via sliding contacts. For this purpose, both electrical machines are designed essentially coaxially to one another, with a fixed yoke of the stator arranged radially on the inside and radially on the outside, which therefore also has fixed windings. This means that the use of sliding contacts can be dispensed with. The two electrical machines are coupled via successive rotors arranged between the stators in the radial direction, with a first rotor belonging to the radially inner electrical machine and connected to the input shaft made of soft magnetic material and reciprocal in the circumferential direction when magnetized due to its geometric design forms magnetic poles. However, a second rotor belonging to the radially external electrical machine and connected to the output shaft has permanent magnet crowns. This is how it can be done corresponding magnetization of the first rotor and rotation of the input shaft, a torque is transmitted to the second rotor and thus to the output shaft. A phase-shifted alternating current excitation of the windings of the radially inner electrical machine results in a rotating field excitation, via which the slip between the first and second rotors can be influenced positively or negatively. A second rotating field can also be generated via the stator associated with the radially outer electrical machine and thus the second rotor can also be subjected to an additional positive or negative torque. Both electrical machines can therefore be operated as a motor or generator.

In addition, the EP 1 524 756 A1 to remove an induction coupling. In conjunction with a motor, this serves in particular as a resistance element for sports equipment. For this purpose, a rotatably mounted shaft is designed in the induction coupling, which carries a permanent magnet package, on the circumference of which a large number of permanent magnets are arranged. The shaft including the permanent magnet package basically forms a first runner or rotor of the induction clutch. The permanent magnet package is also at least partially surrounded by a cage conductor, which is arranged in a sleeve and non-rotatably relative to this sleeve. This sleeve and a flange arranged on the end face and in a rotationally fixed manner on the sleeve form, on the one hand, a bearing bushing in which the shaft is rotatably mounted at least on one side, and on the other hand, a housing of the induction coupling. The shaft is also mounted oppositely within a motor coupling which is connected in a rotationally fixed manner to the bearing bushing or a second flange, which in turn belongs to the bearing bushing or the housing and is therefore also connected in a rotationally fixed manner. To implement the resistance element, the bearing bush or the housing is connected to the aforementioned motor via the motor coupling or the second flange and can therefore be set in rotation via this, whereby the cage conductor can also be set in rotation relative to the permanent magnet package and thus a second rotor respectively rotor is present. By rotating in the magnetic field of the permanent magnets, a current generating an opposite magnetic field is induced in the cage conductor, due to which the permanent magnet package together with the shaft is set in rotation following the rotation of the bearing bush. Resistance is created by acting in the opposite direction to rotation during a sporting activity.

From the EP 0 359 027 A1 is an immediate standby device for a dynamic, uninterrupted power supply, particularly for voltage and frequency stabilization in critical infrastructure such as hospitals. For this purpose, an electric machine, which can be operated in motor or generator mode, or an electric motor and a generator, which are designed to be separate from one another, is mechanically connected via a gearbox to one or two flywheel systems, the second flywheel system via an elastic coupling, in particular an adjustable induction clutch that can be coupled to the transmission. In normal operation, a first flywheel system is maintained at predetermined speeds that differ from one another via the electric machine that is in engine operation and the second flywheel system is maintained at predetermined, mutually different speeds via at least one further electric motor. In the event of a power failure or a network malfunction, the electrical machine switches to generator operation, with a drop in speed via the first flywheel system and thus a drop in frequency and voltage in the network being kept within permissible limits. In addition, the second flywheel system is switched on via the induction coupling, with an existing speed difference between the second flywheel system and the electric machine in generator mode being compensated for by pre-excitation of the induction clutch and also speed and thus frequency control to a value of 50 Hertz plus/minus one percent is made possible.

The AU 5 840 173 A a dual, electromechanical energy transmission and conversion system is also known, which serves in particular as a torque converter between two mechanical systems, here a drive such as an internal combustion engine and an output such as the wheels of a motor vehicle, and is also itself intended as a drive. For this purpose, at least two electrical machines are used, which are arranged within a housing and are mechanically and/or electrically coupled to one another. At least one of the electrical machines is designed as a motor, a second of the electrical machines is designed in particular as an induction clutch, with this at least partially functioning as a generator and/or motor. For pure motor or generator operation, a locking element is designed on an input shaft connected to the second electrical machine designed as an induction clutch. In addition to purely electrical operation, in which both electrical machines are used as a drive, mixed operation of the motor vehicle using the internal combustion engine can also be made possible, with part of the energy transfer occurring mechanically and part electrically. A high speed difference between the combustion engine and the wheels When starting off, this can be compensated for by the energy transmission and conversion system acting as a torque converter, whereby depending on the difference in speed, the energy is transferred more electrically or more mechanically. At a high speed difference, the induction clutch driven by the internal combustion engine essentially acts as a generator, with the electrical energy generated being converted into mechanical energy by the electric motor. If there is a small difference in speed, the induction clutch essentially acts as such and the wheels are driven almost exclusively by the combustion engine. In addition to a generator function, the induction clutch can also be used as a motor, as already mentioned. In addition to the actual function of driving the wheels via a drive shaft in purely electric operation, there is also the possibility of starting the internal combustion engine via the drive shaft or even setting a flywheel in rotation.

With the methods described for compensating for fluctuating energy feed-in, it is often difficult to achieve extremely flexible transmission between an energy storage device and the electrical network using a particularly compact design.

The invention is based on the object of designing the aforementioned network in such a way that a compensation of fluctuating power provision in the electrical network is made possible via a flexibly designed, compact energy storage device. Furthermore, the invention is based on the object of providing a method for balancing the fluctuating service provision in this network.

This object is achieved according to the invention with a composite according to the features of claim 1 and a method according to the features of claim 10. The further embodiment of the invention can be found in the subclaims.

According to the invention, a network of an electrical network or a power grid for the transmission and distribution of electrical energy, at least one power plant forming a primary power plant and at least one storage power plant that differs in particular from a (primary) power plant is provided. The electrical network could be designed as an interconnected network or as an island network. It is also conceivable that the network is made up of several, in particular at least two, subnetworks, whereby the subnetworks can be assigned to the same voltage level or to correspondingly different voltage levels.

According to the invention, the power plant has a fluctuating power supply for or a fluctuating energy feed into the electrical network, which means that a uniform power supply and/or energy feed into the network cannot be guaranteed during regular operation of the power plant. The power plant or power plants are therefore energy producers that do not guarantee consistent energy production during normal operation. This applies in particular to power plants whose power provision and/or energy feed into the electrical network is based on the conversion of renewable or regenerative energies into electrical energy. This means that the power plant can be powered, for example, by geothermal energy, hydropower or even marine energy or solar energy. Preferably, however, the power plant is a wind turbine, whereby if several power plants are implemented, the network can therefore also have a wind farm consisting of several wind turbines or several such wind farms.

The at least one storage power plant, which is also present in the network and is connected - electrically - to the electrical network, serves to compensate for the fluctuating power provision of the power plant, whereby the respective storage power plant in turn has at least one electromechanical converter and / or converter and the electromechanical converter and / or Converter has a rotating electrical machine and at least one rotational inertia storage with at least one rotary flywheel. The electric machine, the rotary flywheel and another device are connected to one another at least mechanically, in particular in a force or torque transmitting manner.

In addition, according to the invention, the electrical machine is a first electrical machine and the further device is a component of the converter and/or converter. The device is designed either as a further, second rotating electrical machine or as a magnetic torque clutch with an adjusting device for influencing the mechanical load coupling. In the latter case, the magnetic torque clutch would in particular be magnetostatically excited and preferably designed to be exclusively permanently magnet excited. The magnetic torque clutch would therefore not have an electrical excitation or an electrically excited magnet. The load coupling, for example, of two rotors creates the torque Clutch would be done in particular by changing an axial overlap of the rotors via the adjusting device.

The storage power plant can therefore provide the electrical network with positive and negative control power or control energy. At least coverage of the primary control or the second reserve would be possible, with coverage also being possible depending on the design of the storage power plant, the number of storage power plants in the electrical network, the number of electromechanical converters and/or converters in a storage power plant and/or the design of the rotational inertia storage Secondary control, tertiary control and/or even an hourly reserve is conceivable.

In principle, within the scope of the invention there is the possibility that only the first electrical machine of the storage power plant is electrically connected and/or connectable to the electrical network. However, it is precisely the design of two electrical machines that advantageously offers the possibility of being able to react to different load states of the electrical network and/or different operating states of the storage power plant and thus to be able to optimally compensate for fluctuations in the electrical power provided to the electrical network.

A preferred embodiment would also be for the first electrical machine and the second electrical machine to be electrically connected and/or connectable to the network. On the one hand, it can also be provided that the storage power plant is only connected to a sub-network of the network. On the other hand, there would also be the possibility of connecting the storage power plant to two sub-grids. These sub-networks could not be directly coupled to one another, but could only be connected indirectly - in particular electrically - via the storage power plant. In one embodiment it could be provided that the first electrical machine is connected to a first sub-network and the second electrical machine is connected to a second sub-network. Particularly within such an embodiment, but also in general, it is conceivable that the subnetworks of the electrical network belong to different voltage levels. A storage power plant can therefore be designed at the border of two such voltage levels.

At least one or all electrical machines should be connected to the electrical network via at least one frequency converter. In a preferred design, each of the two electrical machines is connected to the electrical network via a separate frequency converter. Furthermore, at least one or one power isolator can also be designed between the electrical machines or each of the electrical machines of the electromechanical converter and the electrical network.

In addition, the design of the further device of the electromechanical converter and / or converter as a magnetic torque coupling with an adjusting device for influencing the mechanical load coupling advantageously offers the possibility of coupling at least one further consumer, for example in the form of a further energy storage, in particular mechanically to the electromechanical converter, wherein the power and/or energy transmitted between this consumer and the electromechanical converter could be influenced by the adjusting device, in particular controllable and/or regulated.

However, the advantage of being able to couple at least one further consumer to the electromechanical converter is also offered by the design of the further device as the second electrical machine.

A further development of the invention proves to be extremely advantageous if at least one of the electrical machines, in particular exclusively one electrical machine, has two rotors designed to be rotatable relative to one another, so that this electrical machine operates in motor operation, in generator operation and/or in one Clutch operation can be operated. This electrical machine is preferably the further, second electrical machine. Instead of a stator that is fixed in rotation or frame and a rotor that is rotatably mounted relative to this stator, the electrical machine therefore has two rotors that are rotatable or mounted relative to one another, of which one rotor is designed on the inside and one rotor is on the outside of the electrical machine. In addition to motor and generator operation, clutch operation of the second electrical machine in particular can also be achieved. The motor, generator and/or clutch operation takes place depending on the structural design or the structure of the electrical machine, in particular the two rotors, the relative speed of the two rotors relative to one another and/or the feeding or withdrawal of electrical energy from the electromagnetic converter and/or converter. With regard to the structure of the electrical machine, it should be noted that both rotors must be magnetically excited or at least magnetically excitable in order to achieve a particularly bidirectional clutch operation drive the electric machine. For motor and generator operation, a coil arrangement would also have to be implemented in at least one of the rotors. On the one hand, only one, in particular a first, of the rotors could have a coil arrangement and thus be magnetically excitable via a current flow. In addition to the coil arrangement, the arrangement of at least one laminated core would also be conceivable. The further, in particular second, rotor could therefore not have a coil arrangement, but a permanent magnet arrangement would have to be implemented, which would result in constant magnetic excitation. Again, it would also be possible to design at least one laminated core in the further, second rotor. A different design of the electrical machine would also consist in the implementation of a coil arrangement in both rotors, in which case one of the two rotors could have at least one laminated core. In connection with the aforementioned embodiments, internal and/or external excitation can be implemented.

A further particularly promising embodiment of the invention is characterized in that only one of the electrical machines, preferably the first electrical machine, has a stator, in particular that is fixed to the frame, and a rotor designed to be rotatable relative to this stator, so that the electrical machine is in motor operation and/or in can be operated in generator mode. By designing one of the electrical machines with a stator and a rotor instead of two rotors, the design effort of the electromechanical converter remains less complex, which can ensure higher reliability and reduced maintenance of the electromechanical converter and / or converter. In principle, the stator and/or the rotor can be designed exclusively with at least one laminated core and/or at least one short-circuit cage and thus have neither a coil arrangement nor permanent magnets, so that only an inductive coupling would be effected via an alternating magnetic field generated by the rotor and/or stator. However, the - first - electrical machine would only be suitable for providing power and/or transferring energy from the electrical network to the rotational inertia storage. A preferred embodiment is therefore that the stator and/or rotor have at least one permanent magnet. In addition, at least one laminated core can of course also be designed. The stator or the rotor could be arranged on the inside or outside and both internal and/or external excitation of the - first - electrical machine could be formed by implementing a coil arrangement in the stator and / or rotor.

Furthermore, a promising embodiment of the invention can be seen in the fact that at least one rotary flywheel mass of the rotational inertia storage device, which differs in particular from the components of the electrical machines, is arranged between the electric machine and the device and/or the electric machine is connected to the device via the rotary flywheel mass - mechanically - are connected and thus the rotary flywheel and one rotor of the electrical machines form the rotational inertia storage. The two electrical machines are thus mechanically coupled to one another via the rotary flywheel and are also designed to be spaced apart from one another via this. Particularly in the context of this embodiment, but also in general, it is considered advantageous if the rotary flywheel consists of a non-magnetic, i.e. non-ferromagnetic material or materials. This, particularly in connection with the spacing of the electrical machines via the rotating flywheel, reduces a magnetic flux occurring or exchanged between the electrical machines and thus a magnetic coupling of the electrical machines. The rotating flywheel can be connected either to external or internal rotors of the two electrical machines and thus be designed as an external or internal rotor in the electromechanical converter and / or converter.

A design of the electrical network according to the invention can also be classified as advantageous if preferably only one rotor of at least one electrical machine having two rotors is connected to an output and / or drive element or has an output and / or drive element via which a rotary movement of the Rotor is transferable. In an advantageously simple design, a possibility could be provided for coupling a further consumer, in particular mechanically, to the electromechanical converter and/or converter via the electrical machine having two rotors. The electrical machine having two rotors would preferably be the second electrical machine, with the output and/or drive element being designed in particular as a shaft, in particular consequently an output and/or drive shaft. The output and/or drive element can in principle be arranged on each of the rotors of the electric machine having two rotors or can be connected to each of the rotors. However, it is preferably provided that the output and/or drive element is arranged - exclusively - on the external rotor of the electrical machine or connected to it, so that a complex structural design of the electrical machine, in particular by guiding the output and/or drive element to the outside through the external rotor, can be avoided.

In another embodiment, it can also be provided that the torque clutch with adjusting device also has an output and/or drive element in the previously described embodiment.

In a further advantageous development of the invention, the rotational inertia storage and/or a rotor of at least one electric machine having two rotors can be fixed in a rotationally fixed manner or fixed to the frame via a - respective - braking device and/or a - respective - locking element. The rotor that can be fixed in a rotationally or frame-fixed manner would therefore be the rotor that does not belong to the rotational inertia storage and is therefore not firmly connected to the rotary flywheel. Clutch operation of an electric machine having two rotors could thus be prevented at least temporarily by braking to a standstill and/or fixing the rotational inertia storage or one of the rotors of the electric machine and optimal motor and/or generator operation of the first and/or second electrical machine. In addition, it would be conceivable for a combined clutch and motor operation and/or a combined clutch and generator operation to be achieved via the electric machine having two rotors by braking the rotational inertia storage and/or the one rotor of the second electric machine in particular, by only having at least one Temporary braking of the rotational inertia storage and / or one rotor, therefore not to a standstill, but, for example, speed-controlled up to a target speed. Thus, a provision of power and/or a transmission of energy, corresponding to a power and/or energy flow between the rotational inertia storage of the electromechanical converter and/or converter, the further energy storage device and the electrical network, can be controlled or regulated. In order to achieve the highest possible efficiency, the braking device would preferably be designed as a regenerative brake or recuperation brake or would at least have such a regenerative or recuperation brake.

In a further design-favorable embodiment of the electrical network according to the invention, the storage power plant has at least one further energy storage device that differs in particular from the electromechanical converter. This is connected - mechanically - in particular via the output and / or drive element to the electromechanical converter and / or converter and thus to the rotational inertia storage, so that - mechanical - energy can be transferred between the further energy storage device and the rotational inertia storage. This proves to be particularly beneficial in that e.g. B. when a maximum amount of energy that can be stored in the rotational inertial storage is reached, further excess power provided to the network and / or excess energy fed into the network can be transferred to the storage power plant. On the one hand, if there is a deficit in the network and/or in the rotational inertia storage, the energy stored in the further energy storage device can in turn be transferred to the network and/or the rotational inertia storage.

In one embodiment of the invention it is further provided that the energy storage device has a potential energy liquid storage, a hydropneumatic storage and/or a pneumatic storage. Such a design of the energy storage offers an excellent possibility of transmitting mechanical energy and therefore represents an extremely suitable embodiment for coupling to the electromechanical converter via the further device of the storage power plant designed as an electric machine or torque clutch.

An advantageous embodiment of the invention also consists in the fact that the electrical machines, in particular the rotors and/or stators of the electrical machines, as well as the rotational inertia storage are arranged coaxially with one another. Such a coaxial arrangement allows for a more compact design and thus a smaller space requirement for the storage power plant, particularly in comparison to a series arrangement with axially successive rotational inertia storage units and electrical machines.

According to the invention, a method for compensating for a fluctuating provision of electrical power and/or feeding of electrical energy into the aforementioned electrical network caused by the at least one power plant is also provided. In this case, in load states of the electrical network that differ from one another and/or, in particular operating states of the storage power plant that differ from one another, a provision of, in particular electrical, power and/or a transmission of, in particular electrical, energy takes place between the electrical network and the storage power plant - exclusively - via the first electrical machine, - from finally - via the second electrical machine or via both electrical machines of the electromechanical converter and/or converter of the storage power plant. The method thus creates the possibility of providing and/or transmitting power and/or energy between the electrical network and the storage power plant with a high level of flexibility, that is, of making positive and/or negative control power and/or control energy available to the electrical network .

On the one hand, in a load state of the network in which the network and thus the storage power plant can be powered by the at least one (primary) power plant, for example. B. a wind turbine and / or a wind farm, a surplus power is provided continuously or intermittently, excess energy is flexibly transferred to the storage power plant and thus negative control power and / or control energy is made available. For this purpose, the first and/or the second electrical machine would be operated in motor mode. However, the second electric machine could alternatively also be in combined motor and clutch operation.

The energy thus transferred to the storage power plant via this power and/or energy consumption would consequently be stored in the rotational inertia storage and/or the further energy storage device. In this case, energy can be transferred to the storage power plant or absorbed by it both intermittently and continuously, with the storage power plant being able to be provided with comparatively low powers and, in particular, high powers in the short term due to the transmission according to the invention via the first, second or first and second electrical machines.

It is conceivable that in the case of a continuous but comparatively small excess of electrical power provided by the power plant to the network, the excess or at least part of this excess occurs only via the first electrical machine or the second electrical machine of the electromechanical converter. If, on the other hand, there is a continuously or intermittently high excess of power provided to the electrical network, the excess energy could be transferred via both electrical machines of the electromechanical converter; This may depend on the operating state of the storage power plant, for example the amount of energy stored in the rotational inertia storage and/or the further energy storage device.

If, on the other hand, the electrical network is in a load state in which there is a deficit in the electrical power and/or energy fed into the network provided by the power plant, the deficient energy can be flexibly transferred to the network through the storage power plant or fed into the network and thus positive Control power and/or control energy are made available. For this purpose, the first and/or the second electrical machine would be operated in generator mode. However, the second electric machine could alternatively also be in combined generator and clutch operation. The provision of power by the storage power plant would essentially take place intermittently, delivering high to very high power, in particular peak power, over a comparatively short period of time; This may depend on the operating status of the storage power plant, in this case e.g. B. the amount of energy stored in the rotational inertia storage and/or the further energy storage device.

In principle, it would be conceivable within the scope of the method for the electrical machines to be operated via only one frequency converter connecting the electrical machines to the electrical network. However, a promising development of the method according to the invention is that each of the electrical machines is operated via at least one separate frequency converter that connects the electrical machines to the electrical network. This makes it possible for both electrical machines of the electromechanical converter to be controlled or regulated separately from one another. A possible frequency and/or phase offset can e.g. B. can be controlled and/or regulated by means of a control unit connected to the frequency converters.

Advantageously, in one embodiment of the invention it is further provided that, depending on load states of the electrical network that differ from one another and/or operating states of the storage power plant that differ from one another, provision of, in particular, mechanical power and/or a transmission of, in particular, mechanical energy between the rotational inertia storage and/or the rotating unit of the electromechanical converter and/or converter and the further energy storage device via the second electrical machine. A transfer of energy from the rotational storage device can thus be carried out profitably, in particular depending on the amount of energy stored in the rotational inertia storage device and/or the further energy storage device Inertial storage into the further energy storage device or from the further energy storage device into the rotational inertia storage. For this purpose, the second electrical machine would basically be operated in exclusive coupling mode, so that no energy is transferred between the storage power plant and the electrical network via the second electrical machine. However, a transmission of electrical energy via the first electrical machine and thus between the rotational inertia storage and the electrical network would be conceivable. In addition to the exclusive clutch operation, the second electric machine could also be operated in a combined clutch and motor operation or clutch and generator operation, so that in addition to the transmission of energy between the rotational inertia storage and the further energy storage device, energy can also be transferred between the electrical network via the second electric machine and the storage power plant, in particular the rotational inertia storage or the further energy storage device.

Furthermore, an embodiment of the invention is to be viewed as advantageous if in a - first - load state of the network, in which there is an excess of power provided to the network or energy fed into the network and / or in a - first - operating state of the storage power plant, in which there is a high deficit of energy, in particular mechanical energy, stored in the storage power plant, at least part of the excess power or energy is transferred to the storage power plant via the first and second electrical machines. So, especially if there is a high or very high surplus in the network through the power plant, for example. B. power provided at short notice, the high deficit of energy stored in the storage power plant can be advantageously reduced by the simultaneous transmission via both electrical machines, especially in a short period of time. A high deficit of energy stored in the storage power plant occurs in particular when no or only a small amount is stored in the storage power plant, thus in the rotational inertia storage and/or the further energy storage device. A small amount can be quantified by the fact that at most 20 percent, preferably at most 10 percent, particularly preferably at most 5 percent of a total maximum amount of energy that can be stored in the storage power plant or in the rotational inertia storage and / or the further energy storage device is stored in the storage power plant.

In general, but especially in connection with the embodiment of the invention described above, a promising design form of the method according to the invention also lies in the fact that when there is a high deficit - especially in the first operating state - at least partly due to a standstill or a small rotation of the rotational inertia storage of the - mechanical - energy stored in the storage power plant, at least part of the excess power provided to the network or energy fed into the network is transferred via the first electrical machine and the second electrical machine exclusively into the rotational inertial storage. In the event of an excess of power and/or energy provided, at least part of the excess energy can preferably initially be transferred to the rotational inertia storage, which serves in particular as a main energy storage of the storage power plant, and thus initially stored therein. This is advantageous, among other things, because the rotational inertia storage usually has a more agile response or shorter response times than embodiments of the other energy storage device, which e.g. B. has a potentially energetic liquid storage, a hydropneumatic storage and / or a pneumatic storage or is designed as such. The high deficit of energy stored in the rotational inertia storage, manifested by a standstill or a slight rotation of the rotational inertia storage, can be advantageously reduced by the simultaneous transmission of energy via both electrical machines, especially in a short period of time, in that the speed of the rotational inertia storage - significantly - is increased. A low rotation of the rotational inertia storage occurs in particular when a speed of the rotational inertia storage is at most 20 percent, preferably at most 10 percent and particularly preferably at most 5 percent of a maximum permissible speed of the rotational inertia storage.

Advantageously, in one embodiment of the method according to the invention, it is also envisaged that - in particular in the first operating state - one of the rotors of the second is used to provide power and/or a transfer of energy between the rotational inertia storage of the storage power plant and the electrical network via the second electrical machine electric machine, in particular by means of the braking device assigned to the second electric machine and / or the assigned locking element, is braked and / or locked at least temporarily. The one braked and/or stuck The rotor provided would therefore be the rotor of the second electrical machine that is not connected to the rotary flywheel of the rotational inertia storage. As already shown above, clutch operation of the second electric machine could be prevented and optimal motor and/or generator operation could be achieved by at least temporarily braking to a standstill and/or at least temporarily fixing this rotor of the electric machine - which is not connected to the rotational inertia storage guarantee. In this way, the maximum possible provision of power and/or a transfer of energy between the rotational inertia storage and the electrical network could be realized.

Furthermore, a profitable embodiment of the invention is described in that in a - first or second - load state of the network, in which there is an excess of power provided to the network or energy fed into the network, and / or in a - second - operating state of the storage power plant, in which a high amount of in particular mechanical energy stored in the storage power plant, here in particular in the rotational inertia storage, is transmitted via the second electrical machine - mechanical - energy from the rotational inertia storage and / or - electrical - energy from the network into the further energy storage device. This means that, despite the already high amount of energy stored in the rotational inertial storage, additional excess energy can be transferred from the electrical network to the storage power plant and an otherwise necessary minimization of the power provided to the network by the power plant can be avoided. A transfer of energy to the further energy storage device bypassing the rotational inertia storage would also be possible. It should be mentioned that a high amount of energy stored in the storage power plant is present when a maximum amount of energy that can be stored in the rotational inertia storage or at least 80 percent, preferably at least 90 percent, particularly preferably at least 95 percent of this maximum amount is already stored in the rotational inertia storage. This maximum amount of energy that can be stored in the rotational inertia storage is achieved in particular when the speed of the rotational inertia storage corresponds to a maximum permissible speed of the rotational inertia storage.

A further development of the invention also proves to be profitable if, in a - third - operating state of the storage power plant, in which there is a high deficit of energy, in particular mechanical energy, stored in the storage power plant via the rotational inertia storage, there is a provision of - electrical - power and / or a Transmission of - electrical - energy between or via the network and the further energy storage device of the storage power plant takes place - exclusively - via the second electrical machine. This makes it possible to profitably transfer energy between the further energy storage device and the electrical network, bypassing the rotational inertia storage device. This is particularly advantageous if there is a deficit in the power provided to the electrical network by the power plant and/or energy fed into the network, if no or only a small amount of energy is stored in the rotational inertia storage and thus in the network to compensate for the deficit in power provided by the storage power plant and/or energy must be fed into the network.

Particularly in connection with the above-mentioned development of the method according to the invention, but also in general, an embodiment of the invention is to be viewed as extremely promising, in which - especially in the third operating state - for the provision of power and / or a transmission of energy between the further energy storage device of the Storage power plant and the electrical network via the second electrical machine of the rotational inertia storage is at least temporarily braked and / or determined in particular by means of the braking device assigned to the rotational inertia storage and / or the assigned locking element. In this way, clutch operation of the second electric machine could be prevented and optimal engine and/or generator operation could be ensured by at least temporarily braking to a standstill and/or at least temporarily fixing the rotational inertia storage. This advantageously leads to a maximum possible provision of power and/or a maximum possible transmission of energy between the further energy storage device and the electrical network.

It should also be mentioned that a transmission of energy between the network and the storage power plant in the above context is in particular as a transmission of energy between the at least one power plant and the storage power plant and / or the storage power plant and consumers of the network connected to the electrical network via the electrical Network is to be understood.

• 1 eine vereinfachte Übersichtsdarstellung einer Weiterbildung des erfindungsgemäßen Verbunds mit einer ersten Ausführungsform eines Speicherkraftwerks respektive eines elektromechanischen Wandlers;
• 2 eine zweite Ausführungsform eines Speicherkraftwerks respektive eines elektromechanischen Wandlers.

The invention allows for various embodiments. To further clarify their basic principle, some of them are in the drawings and are described below. The drawings show in

• 1 a simplified overview of a development of the composite according to the invention with a first embodiment of a storage power plant or an electromechanical converter;
• 2 a second embodiment of a storage power plant or an electromechanical converter.

In the 1 a further development of a network according to the invention consisting of the electrical network 1 for the transmission and distribution of electrical energy and several power plants 2 is shown, the power plants 2 electrically connected to the electrical network 1 via a transformer unit functioning as primary power plants and in particular a respective power plant 2 as one Wind turbine is executed. Together these form a wind farm. The power plants 2 designed as wind turbines have a correspondingly fluctuating supply of power into the electrical network 1 due to the conversion of wind energy into electrical energy, which means that a uniform feed of energy into the electrical network 1 cannot be guaranteed during regular operation of the power plants 2. In addition to the power plants 2, the network also has the storage power plant 3, which is also electrically connected to the electrical network 1. The storage power plant 3 serves to compensate for the fluctuating provision of power by the power plants 2, this compensation being carried out via an embodiment of the method according to the invention.

The storage power plant 3 shown now has the electromechanical converter 4 and the electromechanical converter 4 in turn has the two rotating electrical machines 5, 6 and the rotational inertia storage 7. Each of the electrical machines 5, 6 is operated via a separate frequency converter 17, 18 and is therefore electrically connected to the electrical network 1 via this. The two frequency converters 17, 18 are in turn controlled or regulated via the control unit 20, so that between the two electrical machines 5, 6 z. B. a frequency and/or phase offset can be adjusted.

Like the further development of the electromechanical converter 4 1 It can also be seen that only one of the electrical machines 5, 6, here the first electrical machine 5, has an outer stator 11 which is fixed to the frame via the holder 21 and the inner rotor 12 which is designed to be rotatable relative to this stator 11. The rotor 12 of the first electrical machine 5 is designed to be permanently magnet-excited and has a laminated core with permanent magnets integrated into this laminated core. A coil arrangement of the first electrical machine 5, which is used for excitation and induction, is thus designed in the stator 11. As a result, the first electrical machine 5 is designed as an internal rotor and can be operated both in motor operation and in generator operation.

Furthermore, one of the electrical machines 5, 6, here the second electrical machine 6, has two rotors 9, 10 that are rotatable relative to one another. In order to achieve a rotation of the outer rotor 10 relative to the inner rotor 9 of the second electrical machine 6, the outer rotor 10 is rotatably mounted via the pivot bearing unit 22. Again, the inner rotor 9 is designed to be permanently magnet-excited and consequently also has a laminated core with permanent magnets integrated into this laminated core. A coil arrangement of the second electrical machine 6, which serves for excitation and induction, is correspondingly designed in the rotatably mounted outer rotor 10, whereby the electrical machine 5, 6 can be operated in motor operation, in generator operation and/or in clutch operation. In order to enable electrical contact between the rotatably mounted outer rotor 10 of the second electrical machine 6 and the frequency converter 18 or the electrical network 1, the second electrical machine 6, in particular the outer rotor 10, has the sliding contact 23. In other embodiments, such a sliding contact of the rotors 9, 10 and/or the rotor 12 is also conceivable via the rotational inertia storage 7.

Again 1 can also be seen, the - inner - rotor 12 of the first electrical machine 5 and the inner rotor 9 of the second electrical machine 6 together with the rotary flywheel 8 form the rotational inertia storage 7 of the electrical converter 4. In order to avoid crosstalk of the magnetic fluxes of the two electrical machines 5, 6, the rotary flywheel 8 is arranged between the electrical machines 5, 6 and also consists of a non-magnetic material. In particular, the two inner rotors 9, 12 of the electrical machines 5, 6 are connected directly via the rotating flywheel 8 in this embodiment.

In addition to the rotational inertia storage 7 of the electromechanical converter 4, the storage power plant 3 has the further energy storage device 16 to increase the amount of energy that can be stored in the storage power plant 3, which is via the Output and/or drive element 13 is connected to the electromechanical converter 4, so that energy can be transferred - mechanical - between the energy storage device 16 and the rotational inertia storage 7 of the electromechanical converter 4 by a rotary movement, for which the second electrical machine 6 is at least partially operated in a clutch operation would. The output and/or drive element 13 is designed specifically on the outer rotor 10 of the second electrical machine 6, with the further energy storage unit 16 being coupled to the output and/or drive element 13 via the clutch 19.

In order to compensate for a fluctuating provision of electrical power in the electrical network 1 of the network caused by the power plants 2, it is provided that in particular different load states of the electrical network 1 and / or in particular different operating states of the storage power plant 3, a provision of Power or a transmission of energy between the electrical network 1 and the storage power plant 3 via the first electrical machine 5, the second electrical machine 6 or both electrical machines 5, 6 of the electromechanical converter 4 of the storage power plant 3 takes place. In this context, it is also provided that, depending on these load states of the electrical network 1 and/or these operating states of the storage power plant 3, power is provided or energy is transmitted between the rotational inertia storage 7 of the electromechanical converter 4 and the further energy storage device 16 via the second electrical machine 6.

As part of the fluctuating provision of power by the power plants 2, on the one hand there may be a load state of the network 1 in which there is a deficit in power in the network and therefore essentially positive control power must be provided. On the other hand, there can also be a load state of the network 1 in which the network 1 is provided with excess power by the power plants 2. Especially in the case of particularly small or moderate deficits or surpluses, there is the possibility that power is only provided via one of the electrical machines 5, 6 between the network and the storage power plant 3. The electrical energy from the power plants 2 is converted either via the first electrical machine 5 or the second electrical machine 6 of the electromechanical converter 4 into mechanical energy of the storage power plant 3, in particular into kinetic energy of the rotational inertia storage 7 and/or kinetic and/or potential energy the further energy storage device 16 converted and/or vice versa.

However, if there is a load state of the network 1 in which there is an excess of the power provided to the network 1 by the power plants 2 or the energy fed in, as well as an operating state of the storage power plant 3 in which there is a high deficit of energy stored in the storage power plant 3, then such As part of this further development of the method, excess energy is transferred to the storage power plant 3 via the first electrical machine 5 and the second electrical machine 6 in order to minimize the deficit as quickly as possible. Furthermore, in the event of a standstill in this context or a - currently - low rotation of the rotational inertia storage 7, for example in a start-up phase of the rotational inertia storage 7, the excess energy is transferred exclusively to the rotational inertia storage 7, since this serves as the main energy storage of the storage power plant 3. When the energy is transferred in this operating state from the electrical network 1 into the rotational inertia storage 7 of the storage power plant 3 via the second electrical machine 6, the outer rotor 10 of the second electrical machine 6, if there is still residual rotation, may be temporarily braked and then temporarily rotationally fixed or fixed to the frame. For this purpose, the storage power plant 3, specifically the electromechanical converter 4, which is assigned to the outer rotor 10 and in the further development of the 1 braking device 14 acting on the output and/or drive element 13, which also has the locking element 15. In this case, the further energy storage device 16 would be detached from the output and/or drive element 13 via the clutch 19.

In addition to the braking device 14 assigned to the outer rotor 10, the storage power plant 3, here again the electromechanical converter 4, has the further braking device 14 assigned to the rotational inertia storage 7. This in turn also has the locking element 15, whereby the rotational inertia storage 7 is optionally temporarily braked via the braking device 14 in a second operating state of the storage power plant 3 and is then temporarily fixed in a rotationally or frame-fixed manner; This is in view of the fact that in this second operating state of the storage power plant 3, in contrast to the first operating state explained above, when there is again a high deficit of energy stored in the storage power plant 3 via the rotational inertia storage 7, a provision of power between the electrical network 1 and the other Energy storage device 16 of the storage power plant 3 via the second electrical machine 6. Due to the braking and/or fixing of the rotational inertia storage device 7, a quasi-optimal transfer of energy between the electrical network 1 and the further energy storage device 16 can be ensured. The second electrical machine 6 is operated in motor or generator mode.

If, as part of the development of the method, there is also a third operating state of the storage power plant 3, which is determined by the fact that there is a high amount of energy stored in the rotational inertia storage 7 of the storage power plant 3, then in the case of a load state of the network 1, in which there is again a surplus Power provided on the network 1 or energy fed into the network 1 is present, energy is transferred from the rotational inertia storage device 7 and/or energy from the network 1 into the further energy storage device 16 via the second electrical machine 6. On the one hand, the energy can be transferred exclusively from the rotational inertia storage 7 into the further energy storage device 16, for which the second electric machine 6 is operated in - pure - clutch operation. Due to the permanent magnet excitation and the rotation of the inner rotor 9 of the second electrical machine 6, a current which in turn generates a magnetic field is induced in the coil arrangement of the outer rotor 10 of the second electrical machine 6, so that the outer rotor 10 follows the inner rotor and the rotational movement caused thereby is transmitted to the further energy storage device 16 via the output and/or drive element 13. This is coupled to the output and/or drive element 13 via the clutch 19. Here, the speed of the outer rotor 10 approaches the speed of the inner rotor 9, although there is always a slip between the rotors 9, 10. By transferring energy from the rotational inertia storage 7, the energy stored in the rotational inertia storage 7 is minimized, with the speed of the rotational inertia storage 7 consequently decreasing. So can e.g. B. energy can be transferred again from the electrical network 1 into the rotational inertia storage 7 via the first electrical machine 5.

However, instead of transferring energy from the rotational inertia storage device 7, the excess energy can also be transferred - directly - via the second electrical machine 6 into the further energy storage device 16. For this purpose, the coil arrangement of the outer rotor 10 of the second electrical machine 6 would be excited with a current which has at least one frequency corresponding to the speed of the rotational inertia storage 7. A higher frequency is also conceivable. In order to avoid a further transfer of energy into the rotational inertia storage 7 and any associated exceeding of the maximum permissible speed of the rotational inertia storage 7, this can be braked on the one hand via the braking device 14 assigned to the rotational inertia storage 7. In order to avoid a reduction in efficiency, the braking device 14 would be designed as a recuperation brake. Alternatively or additionally, the rotational inertia storage 7 could also be braked by transferring energy from it into the electrical network 1 via the first electrical machine 5, so that the first electrical machine 5 also acts as a braking device 14.

The 2 A second development of the storage power plant 3 and in particular the electromechanical converter 4 can also be seen. The electromechanical converter 4 in turn has the output and/or drive element 13 as well as the two electrical machines 5, 6, of which the first electrical machine 5 has a stator 11 located on the inside and an outer rotor 12 designed to be rotatable relative to this stator 11 . The second electrical machine 6, on the other hand, again has two rotors 9, 10 that are rotatable relative to one another. Here, the inner rotor 9 of the second electrical machine 6 forms the rotational inertia storage 7 with the outer rotor 12 of the first electrical machine 5 and the rotary flywheel 8 arranged radially between the electrical machines 5, 6. In contrast to the design of the electromechanical converter 4 1 are the electrical machines 5, 6, here correspondingly the stator 11, the rotors 9, 10 12 and the rotary flywheel 8 of the development of the electromechanical converter 4 2 arranged coaxially to each other. The rotors 9, 10, 12 and the rotating flywheel 8 are supported on the holder 21 of the stator 11 via the stator 11 fixed to the frame. The rotors 9, 10, 12 are essentially cup-shaped. The outer rotor 12 of the first electrical machine 5 and the outer rotor 10 of the second electrical machine 6 can also be fixed in rotation or position via the braking devices 14 assigned to the rotors 10, 12. The braking devices 14 also have the locking elements 15. In order to avoid crosstalk of a magnetic flux between the electrical machines 5, 6, the rotary flywheel 8 is again made of a non-magnetic material. In addition, to further minimize crosstalk, there is an axial connection between the outer rotor 12 of the first electrical machine 5 and the inner rotor 9 of the second electrical machine 6, the spacer 24 is arranged.

REFERENCE SYMBOL LIST

1

electrical network

2

power plant

3

Storage power plant

4

electromechanical converter

5

first electric machine

6

second electric machine

7

Rotational inertia storage

8th

Rotary flywheel

9

rotor

10

rotor

11

stator

12

rotor

13

Output and/or drive element

14

Braking device

15

Locking element

16

Energy storage device

17

frequency converter

18

frequency converter

19

coupling

20

Control unit

21

bracket

22

Pivot bearing unit

23

Sliding contact

24

Spacer

QUOTES INCLUDED IN THE DESCRIPTION

This list of documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• EP 1485978 A2 [0004]
• DE 19811966 A1 [0006]
• US 7535143 B2 [0007]
• EP 1524756 A1 [0008]
• EP 0359027 A1 [0009]
• AU 5840173 A [0010]

Claims (18)

Composite of an electrical network (1) for the transmission and distribution of electrical energy and at least one power plant (2), the power plant (2) having a fluctuating power feed into the electrical network (1) and therefore not a uniform one in the regular operation of the power plant (2). Energy output can be guaranteed, as well as at least one storage power plant (3) to compensate for the fluctuating power feed of the power plant (2), the storage power plant (3) having at least one electromechanical converter (4) and the electromechanical converter (4) a rotating electrical machine (5) and has at least one rotational inertia storage (7) with a rotary flywheel (8) and the electric machine (5), the rotary flywheel (8) and a further device are connected to one another, characterized in that the electric machine (5) is a first rotating electric machine (5) and the further device is a component of the electromechanical converter (4), the device being designed as a further, second rotating electrical machine (6) or as a magnetic torque clutch with an adjusting device for influencing a mechanical load coupling of the torque clutch. Composite according to Claim 1 , characterized in that at least one of the electrical machines (5, 6) has two rotors (9, 10) which are rotatable relative to one another, so that the electrical machine (5, 6) is in motor operation, in generator operation and/or in clutch operation is operable. Composite according to Claim 1 or 2 , characterized in that only one of the electrical machines (5, 6) has a stator (11) and a rotor (12) designed to be rotatable relative to this stator (11), so that the electrical machine (5, 6) in motor operation and / or can be operated in generator mode. Composite according to at least one of the preceding claims, characterized in that the rotational flywheel (8) of the rotational inertia storage (7) is arranged between the electrical machine (5, 6) and the device and/or the electrical machine (5, 6) and the device are connected to each other via the rotary flywheel (8) and thus the rotary flywheel (8) and one rotor (9, 10, 12) of the electrical machines (5, 6) form the rotational inertia storage (7). Composite according to at least one of the preceding claims, characterized in that a rotor (9, 10) of at least one electrical machine (5, 6) having two rotors (9, 10) is connected to an output and / or drive element (13) or has an output and/or drive element (13), via which a rotary movement of the rotor (9, 10) can be transmitted. Composite according to at least one of the preceding claims, characterized in that the rotational inertia storage (7) and/or a rotor (9, 10) of at least one electric machine (5, 6) having two rotors (9, 10) via a braking device (14) and/or a locking element (15) can be fixed in a rotationally fixed manner. Composite according to at least one of the preceding claims, characterized in that the storage power plant (3) has at least one further energy storage device (16) which is connected to the electromechanical converter (4), so that between the energy storage device (16) and the rotational inertia storage device (7) the electromechanical converter (4) energy can be transferred. Composite according to at least one of the preceding claims, characterized in that the energy storage device (16) has a potentially energetic liquid storage, a hydropneumatic storage and/or a pneumatic storage. Composite according to at least one of the preceding claims, characterized in that the electrical machines (5, 6) and the rotating flywheel (8) are arranged coaxially to one another. Method for compensating for a fluctuating provision of electrical power in the electrical network (1) of the network caused by the at least one power plant (2) according to at least one of the preceding claims, characterized in that in load states of the electrical network (1) and/or operating states of the storage power plant (3) a provision of power between the electrical network (1) and the storage power plant (3) via the first electrical machine (5), the second electrical machine (6) or both electrical machines (5, 6) of the electromechanical converter (4) of the storage power plant (3). Procedure according to Claim 10 , characterized in that each of the electrical machines (5, 6) is operated via a separate frequency converter (17, 18) connecting the electrical machines (5, 6) to the electrical network (1). Procedure according to Claim 10 or 11 , characterized in that depending on load conditions of the electrical network (1) and / or operating conditions of the storage power plant (3), power is provided between the rotational inertia storage (7) of the electromechanical converter (4) and the further energy storage device (16) via the second electric machine (6) takes place. Method according to at least one of the preceding Claims 10 until 12 , characterized in that in a load state of the network (1), in which there is a surplus of power provided to the network (1), and / or in an operating state of the storage power plant (3), in which there is a high deficit in the storage power plant (3 ) stored energy is present, at least some excess energy is transferred to the storage power plant (3) via the first electrical machine (5) and the second electrical machine (6). Method according to at least one of the preceding Claims 10 until 13 , characterized in that if there is a high deficit of energy stored in the storage power plant (3) at least partly due to a standstill or a slight rotation of the rotational inertia storage (7), at least part of the excess of the power provided to the network (1) or into the network (1) fed-in energy via the first electrical machine (5) and the second electrical machine (6) is transmitted exclusively into the rotational inertia storage (7). Method according to at least one of the preceding Claims 10 until 14 , characterized in that to provide power between the rotational inertia storage (7) of the storage power plant (3) and the electrical network (1) via the second electrical machine (6) one of the rotors (9, 10) of the second electrical machine (6) is at least temporarily braked and/or detected. Method according to at least one of the preceding Claims 10 until 15 , characterized in that in a load state of the network (1), in which there is an excess of power provided to the network (1) or energy fed into the network (1), and / or in an operating state of the storage power plant (3), in which there is a high amount of energy stored in the storage power plant (3), energy is transferred from the rotational inertia storage device (7) and/or energy from the network (1) to the further energy storage device (16) via the second electrical machine (6). Method according to at least one of the preceding Claims 10 until 16 , characterized in that in an operating state of the storage power plant (3), in which there is a high deficit of energy stored in the storage power plant (3) via the rotational inertia storage (7), power is provided between the electrical network (1) and the further energy storage device (16) of the storage power plant (3) via the second electrical machine (6). Method according to at least one of the preceding Claims 10 until 17 , characterized in that in order to provide power between the further energy storage device (16) of the storage power plant (3) and the electrical network (1) via the second electrical machine (6), the rotational inertia storage (7) is at least temporarily braked and / or detected.

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