Power supply system for a water-based facility with first and second winding systems of a generator system for supplying different DC voltage buses

Description

[0001] The invention relates to an energy supply system for a water-based facility, in particular a floating facility. Floating facilities include, for example, ships, submarines, oil platforms, and / or gas platforms. Examples of ships include cruise ships, frigates, container ships, aircraft carriers, icebreakers, etc. Floating facilities are water-based facilities. Oil platforms or gas platforms located on the seabed are examples of water-based facilities. In addition to the energy supply system, the invention also relates to a corresponding method for operating this energy supply system.

[0002] An energy supply system for a water-based facility or a floating facility has energy sources. References to a floating facility below also refer to a water-based facility, and vice versa. Examples of energy sources include a diesel generator, a fuel cell, a battery / accumulator, a flywheel, etc. The diesel in the diesel generator can be operated with heavy fuel oil and / or LNG, for example. The energy supply system is intended, for example, to supply electrical energy to a drive system of the floating facility, or to auxiliary systems or other consumers such as air conditioning, lighting, automation systems, etc. The energy supply system can be designed in such a way that, even in the event of a power source failure, at least emergency operation for the floating facility can be enabled.The power supply of a floating facility includes, in particular, an on-board power system. The on-board power system (the electrical system) serves to supply electrical power to the floating facility.

[0003] If, for example, a floating facility is capable of maintaining its position, it will have a plurality of drives. These drives will in particular have a propeller or a waterjet. These drives for maintaining the position of the ship in the water and / or for propelling the ship in the water must in particular be kept operational independently of one another. If, for example, this floating facility has two or more drive systems in the stern area, such as two POD drives or two propellers with shafts protruding from the ship's hull, which are driven by an electric motor and / or by a diesel engine with a shaft generator, it is advantageous if these can be supplied with electrical energy independently of one another in the event of a fault in one of the drives.

[0004] EP 3 046 206 A1 discloses a power distribution system on a ship. This system comprises a first medium-voltage bus and a second medium-voltage bus. The second medium-voltage bus has no direct connection to the first medium-voltage bus. Furthermore, the power distribution system comprises a first low-voltage AC bus and a first power converter between the first medium-voltage bus and the first AC bus to enable a power flow from the first medium-voltage bus to the first AC bus. Furthermore, the power distribution system also comprises a second AC bus and a second power converter between the second medium-voltage bus and the second AC bus to enable a power flow from the second medium-voltage bus to the second AC bus.

[0005] WO 2016 / 116595 A1 discloses a device for distributing stored electrical energy on a ship, which also includes one or more AC consumers. In the event of a failure of a primary electrical power supply, a DC network with a plurality of electrical energy storage elements is provided to enable the supply of one or more AC consumers with stored electrical energy. Several interrupter systems are provided in the DC circuit to disconnect one or more auxiliary electrical power sources.

[0006] DE 102009043530 A1 discloses a power supply system with an electric drive shaft. The electric drive shaft has at least one variable-speed generator for generating a voltage with variable amplitude and variable frequency, and at least one variable-speed drive motor supplied with this voltage. The generator has, for example, a superconductor winding, in particular a high-temperature superconductor (HTS) winding.

[0007] WO 2010 / 022389 A1 discloses a power supply system suitable for the simultaneous supply of ship propulsion and operational loads. The system comprises at least one generator configured with at least a first and a second armature winding configured to respectively output a first and a second AC power signal having different voltages, wherein the at least two armature windings are arranged in the same stator slots so that they are magnetically coupled. The system further comprises at least a first and a second rectifier circuit coupled to the generator for converting the first and second AC power signals into a first and a second DC power signal.

[0008] WO 2005 / 049418 A2 describes an electrical energy generation, distribution and on-board power supply system that can be adapted to a wide variety of operating conditions, including emission-free ones, and can be kept operational in the event of failure of parts of its electrical energy supply networks.

[0009] In on-board electrical systems, electrical energy is often required at different voltage levels and / or in different voltage forms (AC or DC). For this purpose, primary energy is provided from one or more internal combustion engines, for example, and converted into electrical energy by one or more three-phase generators (asynchronous generator or synchronous generator). The synchronous generator, for example, is a permanently excited synchronous generator. This electrical energy is generated in particular at the highest voltage level available in the on-board electrical system (upper voltage level of the supply network). Transformers and / or DC / DC converters, for example, are used to generate further voltage levels. The transformers are generally heavy and have a high volume, losses of around 1%, and the input and output frequencies are always identical.For example, the entire generated generator power is fed in via the upper voltage level and distributed to a main energy bus. In many systems or on-board electrical systems, the main energy bus is a 3-phase alternating current bus (AC), which creates an AC network. The electrical energy is distributed primarily via one or more switchboards. In AC networks, the frequency of a lower network is the same as the frequency of the upper network. The lower network differs from the upper network in terms of voltage, with the upper network having a higher voltage than the lower network. Using an AC network with an AC energy bus to distribute electrical energy can be disadvantageous if the frequency in the upper voltage level is variable. Variable frequencies are particularly the result of variable-speed combustion engines.In order to supply a lower voltage level from an upper AC power bus, several transformers are usually required. The energy is transmitted via the upper AC main energy bus, i.e. via the upper voltage level. Within a voltage level, the energy can be distributed via switchgear. An AC switchgear is used to distribute AC. The voltage level of the energy bus or the voltage level depends largely on the installed power. The various consumers are fed and the lower voltage levels are supplied with energy. Transformers are required in AC networks to connect the different voltage levels, which means that the voltage levels have the same frequency. The transformation ratio of the transformer used determines the ratio of the voltages.

[0010] Since the consumers on the floating facility have different requirements for the energy supply system and also draw energy from the energy supply system depending on the operating state of the floating facility, the energy supply system must be designed to be as flexible as possible. One object of the present invention is therefore to provide a flexible energy supply system and a flexible method for operating such an energy supply system.

[0011] The object is achieved according to claim 1 or 10. Further embodiments of the invention are disclosed in claims 2 to 9 and 11.

[0012] A power supply system for a water-based facility, and in particular for a floating facility, has a first DC voltage bus for a first DC voltage and a second DC voltage bus for a second DC voltage. This means that the first DC voltage bus is suitable or provided for a first DC voltage level and the second DC voltage bus is suitable or provided for a second DC voltage level. The first DC voltage level is in particular higher than the second DC voltage level. The first DC voltage level therefore corresponds to the first DC voltage bus and the second DC voltage level corresponds to the second DC voltage bus. For example, the DC voltage levels differ by a factor of between 5 and 50. Ratios of, for example, 1:5 to 1:20 are therefore possible. The same applies to a water-based or floating facility.floating facility, in particular a ship, which has an energy supply system in one of the described embodiments.

[0013] Examples of a waterborne facility are: a ship (e.g. cruise ships, container ships, feeder ships, support vessels, crane ships, tankers, combat ships, landing ships, icebreakers, etc.), a floating platform, a platform permanently anchored to the seabed, etc.

[0014] A power supply system for a water-based facility, in particular a floating facility, can also be implemented with a first DC voltage bus for a first DC voltage and with a second DC voltage bus for a second DC voltage. The power supply system has a first energy source, the first energy source having a generator system that has a first winding system for supplying the first DC voltage bus and a second winding system for supplying the second DC voltage bus. Thus, different voltage levels can be supplied with one generator system. If the power supply system has additional energy sources, these can also have such a generator system.

[0015] According to the invention, the floating or water-based facility and / or the energy supply system has a first zone and a second zone. Here too, as already noted above, a floating facility should also be understood to mean a water-based facility in the following. The floating facility can also have more than two zones. The type of zones can vary. For example, a zone can be a fire zone. Zones can be separated from one another by one or more bulkheads. Chambers of this type are formed which can serve, for example, to protect against fire and / or to prevent the floating or water-based facility from sinking. A bulkhead or bulkheads can be designed or constructed to be airtight and / or liquid-tight and / or fire-retardant.In a floating facility such as a ship, for example, there may be at least one transverse bulkhead and / or one longitudinal bulkhead and / or one watertight deck. However, zones or chambers are formed. A chamber can represent a zone, just as a zone can represent a chamber. The energy supply system for the floating or water-based facility has a first energy source and a second energy source, wherein the first energy source in the first zone is provided for feeding at least one DC voltage bus of the at least two DC voltage buses, and wherein the second energy source in the second zone is provided for feeding at least one DC voltage bus of the at least two DC voltage buses. The first energy source can therefore, for example, be provided for feeding only the first DC voltage bus or for feeding both the first DC voltage bus and the second DC voltage bus.The same applies to the second energy source, which can, for example, be provided to supply only the first DC voltage bus or to supply both the first DC voltage bus and the second DC voltage bus. The supply of the respective DC voltage bus particularly relates to a direct connection to the DC voltage bus. A direct connection is understood to be an electrical connection in which no further DC bus is interposed for energy distribution. However, a direct connection can, for example, have a power converter, a transformer, a switch, or a DC / DC controller. Energy sources of the energy supply system can, for example, be of the following types: a diesel generator, a gas turbine generator, a battery, a capacitor, SUPER-Caps, a flywheel storage device, or fuel cells.

[0016] According to the invention, the energy supply system is at least partially structured according to zones. In particular, the spatial structure corresponds to the zone division for at least two zones. Zones of the water-based facility are created, in particular, by a structural feature such as a bulkhead. A structure of the energy supply system is created, in particular, by switching devices that can establish or break an electrical connection. Sections in the energy supply system can be formed by such switching devices.

[0017] The first DC bus can be divided into sections. This division is achieved using medium-voltage switching devices. The first DC bus is therefore at medium voltage. The second DC bus can also be divided into sections. This division is achieved using low-voltage switching devices. The second DC bus is therefore at low voltage.

[0018] In one embodiment of the energy supply system, which here, as well as up to this point and below, refers to all energy supply systems described, the first winding system is designed for a first voltage and the second winding system is designed for a second voltage, wherein the first voltage is greater than the second voltage. The generator system has, for example, only one generator or, for example, two generators. The generator is in particular a synchronous generator. Asynchronous generators and / or PEM generators can also be used. If the generator has a low-voltage winding system and a medium-voltage winding system, it has, in particular, a large Xd''. In one embodiment of the generator, this can have a large xd". This reduces the short-circuit current contribution of the generator and enables a simpler design of a short-circuit-proof rectifier.This reduced short-circuit current also reduces the mechanical stress on the shaft train in the event of a short circuit. In particular, the short-circuit-proof design of the rectifier enables a simple design of the power supply system, as no additional short-circuit protection elements are required, thus enabling a direct connection between the generator and the rectifier without any isolating devices.

[0019] This is particularly advantageous at the medium-voltage level, since isolating or protective devices such as circuit breakers or fuses require a lot of space, are significantly expensive, or are sometimes not available. The three-phase medium-voltage connection of the generator can, for example, be connected to a diode rectifier or a regulated rectifier and thus feed the medium-voltage DC bus. This also applies in a similar way to the three-phase low-voltage connection for the low-voltage DC bus. The power converter for the low-voltage DC bus can, in particular, also be an Active Front End (AFE). This in particular has four-quadrant operation. This makes it possible, for example, to feed electrical energy from batteries into the low-voltage DC bus and from there via the Active Front End into the medium-voltage DC bus.The Active Front End is an active rectifier that allows energy flow in both directions.

[0020] In one embodiment of the energy supply system, a distinction is made between primary energy sources and secondary energy sources. These types of energy sources relate to their assignment to a respective bus. These types of energy sources relate to any type of energy source, such as a diesel generator, a battery, a fuel cell, a gas turbine with generator, SUPER-Caps, flywheel storage, etc. Primary energy sources are assigned to the first direct current bus (DC bus), with a primary energy source serving in particular to generate electrical energy for the main propulsion of the floating or water-based facility. For example, one or more primary energy sources can also serve to supply another, in particular downstream, DC bus (has a lower DC voltage than the supplying DC bus).This assignment means that no further DC bus is interposed between this primary energy source and the first DC bus. Secondary energy sources are assigned to the second DC bus, with a secondary energy source serving in particular to generate electrical energy for operating systems of the floating or water-based device that do not serve the main propulsion of the floating device. This assignment also means that no further DC bus is interposed between this secondary energy source and the second DC bus. In one embodiment, it is also possible to use at least one secondary energy source assigned to the second DC bus to supply the first DC bus and in particular to supply the main propulsion systems.Examples of operating systems of the floating facility include (on-board power supply, hotel operations, weapons systems, etc.). In one embodiment of the energy supply system, secondary energy sources are selected so that they can respond more quickly to load fluctuations if necessary. The load is, for example, at least one drive motor for driving the floating facility and / or other electrical consumers of the floating facility, for example, pumps, compressors, air conditioning systems, cable winches, on-board electronics, etc. On a cruise ship, electrical consumers for, for example, the air conditioning, galleys, laundry, lighting, etc. are also referred to as hotel load.

[0021] The energy supply system can have multiple energy sources of the same type. In one embodiment of the energy supply system, energy sources of different types can be located in different zones. This can increase the reliability of supply within the floating facility, for example, in emergencies and / or in the event of a fault. In another embodiment, energy sources of different types can be located in the same zone.

[0022] In one design of the power supply system, the intermediate circuit voltage is measured at the smallest load, i.e., the lowest power, so that an inverter can be used for this. For larger loads, a single inverter is used as long as it is available. For larger loads that are too large for an inverter with the selected voltage, parallel inverters or motors with multiple winding systems are used. This approach allows for the cost-optimized implementation of medium-voltage DC systems.

[0023] For example, the intermediate circuit voltage for a 3.5 MW thruster load is set to 4.5 kV DC (3.3 kV three-phase). The 3.5 MW is the smallest load connected to the medium-voltage DC system. Another 12 MW load is also operated with 3.3 kV three-phase voltage, and thus with 4.5 kV DC. This load is operated with two parallel converters or with a machine with two winding systems. Two machines on one shaft are also possible.

[0024] The design goal of keeping the medium-voltage DC bus in the voltage range of 3.2 kV to 6 kV ensures a cost-optimized system.

[0025] Higher power outputs are achieved by parallel connection and / or multi-winding machines.

[0026] The reduced medium-voltage DC voltage specification also reduces the construction volume and costs for the semiconductor switches between the zones as well as the costs for the short-circuit protection of the inverters

[0027] The same procedure can be followed for the rectifiers on the feed-in side.

[0028] By using a first DC bus and a second DC bus in the floating device, electrical energy can be easily transferred from one bus to the other without unnecessary losses. This is particularly advantageous in the event of a fault in which one or more energy sources for the first bus fail. If energy levels are linked via an AC connection, this can lead to higher losses, particularly in the event of a fault. In DC networks, the energy is first rectified in order to be distributed across the upper DC voltage (conversion 1). An AC voltage must then be generated from the DC voltage using an inverter (conversion 2). The inverter must fulfill the same functions as a generator (selectivity and frequency control in the lower voltage level). A transformer is required to adapt the voltage (conversion 3).This triple conversion is associated with losses of approximately 3-3.5%. The component costs and weight are very high. The inverters used are sensitive to harmonics at the lower voltage level. Connecting motors and non-linear loads to the inverters is also problematic and limited. Losses can be reduced using the proposed power supply system, which features a first DC bus and a second DC bus.

[0029] In one embodiment of the energy supply system, in addition to the first energy source and the second energy source, it also has a third energy source. The first energy source and the second energy source are, for example, primary energy sources, and the third energy source is a secondary energy source. The third energy source can be used, for example, for peak shaving and / or as a spinning reserve. This means that peaks in the floating facility's energy consumption that cannot be quickly covered by the primary energy source can be covered by the secondary energy source and / or energy can be made available if one energy source fails.

[0030] In one embodiment of the energy supply system, this has a medium-voltage direct voltage bus with a direct voltage of 3 kV to 18 kV, which is designed as a ring bus, and a low-voltage direct voltage bus with a direct voltage of 0.4 kV to 1.5 kV, which is designed as a ring bus.

[0031] In one embodiment of the power supply system, a three-phase alternating current bus (AC bus) can be used as an energy bus, in particular as an additional main power bus or as a replacement for the DC bus. A DC distribution system (DC bus) and / or an AC distribution system (AC bus) can also be used at a low-voltage level.

[0032] In one embodiment of the power supply system, the first winding system is electrically connected to the first DC bus for transformerless power supply. Eliminating a transformer allows for weight, volume, and / or cost savings.

[0033] In one embodiment of the power supply system, the second winding system is electrically connected to the second DC bus for transformerless power supply. Here, too, weight, volume, and / or cost are saved by eliminating the transformer.

[0034] In one embodiment of the energy supply system, the generator system comprises a first generator with the first winding system and a second generator with the second winding system, wherein the first generator and the second generator are driven by a common shaft system. The first generator and the second generator are particularly rigid, i.e., rigidly coupled. By using two generators for the two winding systems, the design of the generators can be kept simple.

[0035] In one embodiment of the energy supply system, the generator system is a multi-winding system generator, wherein the stator of the multi-winding system generator has the first winding system and the second winding system or additional winding systems. In this way, a compact generator system can be formed.

[0036] In one embodiment of the power supply system, the multi-winding system generator has slots that relate to the first winding system and the second winding system. This allows for a compact design.

[0037] According to the invention, the water-based device, such as in particular the floating device, comprises a first zone, a second zone, and a second energy source. The first energy source is provided in the first zone for supplying at least one of the at least two DC voltage buses, and the second energy source is provided in the second zone for supplying at least one of the at least two DC voltage buses. This improves the reliability of the electrical energy supply to the DC voltage buses.

[0038] In one embodiment, the two winding systems of the generator can be arranged in the slots in such a way that the best possible decoupling is achieved to avoid interference between the winding systems. Adequate decoupling is achieved if the different winding systems are installed in different slots.

[0039] A power supply system for a water-based facility, in particular a floating facility, can also be implemented with a first DC bus for a first DC voltage and a second DC bus for a second DC voltage, wherein a first energy source has at least three feeding electrical connections to the DC buses, wherein at least one of the DC buses has sections. This can also improve the supply reliability of the power supply system.

[0040] In one embodiment of the energy supply system, a first supply connection of the at least three supply electrical connections supplies a first section, and a second supply connection of the at least three supply electrical connections supplies a second section of the same DC bus, with a third supply connection of the at least three supply electrical connections supplying a section of the further DC bus. Thus, the supply of electrical energy can be distributed across different DC buses.

[0041] In one embodiment of the energy supply system, it has a fourth supply connection of the first energy source, wherein two of the at least four supply connections are provided for supplying the first DC voltage bus in different sections of the first DC voltage bus, and wherein two further of the at least four supply connections are provided for supplying the second DC voltage bus in different sections of the second DC voltage bus. This increases the operational reliability of the water-based facility.

[0042] According to the invention, a power supply system for a water-based facility, in particular a floating facility, can also be implemented with a first DC bus for a first DC voltage and a second DC bus for a second DC voltage, wherein a first energy source has at least two feeding electrical connections to the DC buses, wherein at least one of the DC buses has sections. This can also improve the supply reliability of the power supply system.

[0043] In one embodiment of the energy supply system, a first supply connection of the at least two supply electrical connections supplies a first section, and a second supply connection of the at least two supply electrical connections supplies a second section of the same DC bus, or the second supply connection of the at least two supply electrical connections supplies a section of the further DC bus. Thus, the supply of electrical energy can be distributed across different DC buses.

[0044] In one embodiment of the energy supply system, it has a third and fourth supply connection of the first energy source, wherein two of the at least four supply connections are provided for supplying the first DC voltage bus in different sections of the first DC voltage bus, and wherein two further supply connections of the four supply connections are provided for supplying the second DC voltage bus in different sections of the second DC voltage bus. This increases the operational reliability of the water-based facility.

[0045] In one embodiment of the energy supply system, a first supply connection of the at least two supply electrical connections supplies a first section, and a second supply connection of the at least two supply electrical connections supplies a second section of the same DC bus, with a third supply connection supplying a section of the further DC bus. Thus, the electrical energy supply can be distributed across different DC buses.

[0046] In one embodiment of the energy supply system, the water-based facility comprises a first zone and a second zone, wherein the first DC bus and / or the second DC bus extends across the first zone and / or the second zone, wherein the first energy source is provided for supplying sections of the first DC bus and / or the second DC bus in different zones. This allows for increased redundancy for supplying the DC buses with electrical energy.

[0047] According to the invention, the energy supply system comprises a second energy source, wherein the first energy source is provided in the first zone for supplying at least one of the at least two DC voltage buses, and wherein the second energy source is provided in the second zone for supplying at least one of the at least two DC voltage buses. Thus, both DC voltage buses can be supplied with electrical energy, even if only one energy source is active.

[0048] In one embodiment of the power supply system, a section of the first DC bus has both a supply connection to the first power source and a further supply electrical connection to the second power source. This can also improve the flexibility of the system.

[0049] In one embodiment of the energy supply system, a section of the second DC bus has both a supply connection to the first energy source and a further supply electrical connection to the second energy source. However, supply connections can generally also have a switch to flexibly activate or deactivate the supply connection (the supply electrical connection).

[0050] In one embodiment of the power supply system, at least one of the DC buses can be configured or is configured as a ring bus. The ring bus can be split using a switch. In particular, a ring bus can be divided into two smaller buses. The smaller buses can, in turn, be converted into ring buses using additional elements. The ability to split the ring bus allows for flexible response to faults.

[0051] In one embodiment of the power supply system, the switches for disconnecting the bus and / or ring bus are designed as ultrafast switching elements, particularly as semiconductor switching elements or hybrid switching elements with a tripping time in the range of 1 us to 150 us. Hybrid switching elements comprise mechanical, semiconductor, and / or electronic elements. The fast tripping reduces the occurring short-circuit current and prevents the fault from negatively impacting the adjacent zone. This prevents further failures in neighboring zones.

[0052] According to the invention, the first DC voltage bus is provided for a first DC voltage and the second DC voltage bus is provided for a second DC voltage, wherein the first DC voltage is greater than the second DC voltage. In particular, the lower voltage is a low voltage (LV) and the higher voltage is a medium voltage (MV). The low voltage is in particular between 400V and 1000V. In the future, low-voltage systems up to a voltage of 1500V are therefore also expected to be realized. The medium voltage is greater than 1000V or 1500V, in particular between 10kV and 20kV or between 5kV and 20kV. The following values ​​​​for the medium voltage are suitable, for example: 5kV, 6kV, 12kV and 18kV.In particular, the different voltage levels of the DC bus also offer a cost-optimized allocation of loads (particularly due to the cost of the power electronics), with lower-power loads being allocated to the lower voltage. Allocation refers to the electrical connection of the load to the DC bus.

[0053] In one embodiment of the energy supply system, the first DC bus is connected to the second DC bus, for example, via at least one of the following couplings: o DC / DC converter o Inverter - Transformer - Rectifier

[0054] According to the invention, the first DC voltage is greater than the second DC voltage. The first DC voltage is a medium voltage (MV) and the second DC voltage is a low voltage (LV), whereby energy transfer from the first DC bus to the second DC bus is possible, as is energy transfer from the second DC bus to the first DC bus. This increases the flexibility, usability, and / or fault tolerance of the power supply system.

[0055] According to the invention, the first DC bus is provided for a first DC voltage, and the second DC bus is provided for a second DC voltage, wherein the first DC voltage is greater than the second DC voltage. Thus, loads such as motors, electronics, heaters, etc., can be supplied with electrical energy via a suitable voltage level.

[0056] In one embodiment of the power supply system, at least one of the DC voltage buses is designed to extend over at least two zones. This allows, for example, a zone that does not have its own power source to be supplied with electrical energy.

[0057] In one embodiment of the power supply system, a zone can be bridged using a bypass. The bypass can be understood as part of a ring bus, with branches separated within the bypass area. In one embodiment, the bypass can also be implemented via an additional DC voltage level. For example, a zone that is flooded or in which a fire has broken out can be disconnected from the electrical supply without affecting another zone into which the corresponding bus extends.

[0058] In one embodiment of the power supply system, at least one of the DC voltage buses has sections, wherein the sections are zone-specific. The sections can be separated from one another, for example, by means of switches. A switch can be a mechanical switch and / or a mechanical and semiconductor switch and / or a semiconductor switch.

[0059] In one embodiment of the power supply system, two zones can have two sections. In another embodiment, a zone can have two sections from the same bus. In another embodiment, each zone with a section has its own energy source.

[0060] In one embodiment of the power supply system, the first energy source in the first zone is provided to supply the first DC bus and the second DC bus. Thus, for example, both voltage levels can be supplied with energy in one zone.

[0061] In one embodiment of the power supply system, the first DC bus is provided to supply the second DC bus. Thus, the second DC bus can also be supplied with power by a power source connected to the first DC bus.

[0062] In one embodiment of the energy supply system, this has a three-phase bus, wherein the second DC bus is provided for feeding the three-phase bus. The three-phase bus can extend over at least two zones or be limited to one zone. In one embodiment, it is also possible for one or more zones to be bridged by the three-phase bus, i.e. there is a bypass of at least one zone. The three-phase bus (alternating current) is provided for supplying alternating current suppliers. In a cruise ship, for example, these can also be kitchen appliances that can be connected to sockets, such as toasters, waffle irons, or coffee machines.

[0063] In one embodiment of the energy supply system, it is possible, particularly depending on a ship's application, to at least partially integrate an AC distribution network at the low-voltage level into a medium-voltage DC distribution network or to create individual DC islands within the zones that are connected between the zones via AC connections. In one embodiment of the energy supply system, individual DC islands are connected to each other via DC / DC converters.

[0064] In one embodiment of the energy supply system, a zone can be operated autonomously. This autonomous zone has at least one of the energy sources, which can be fed by the first DC bus and / or the second DC bus. The first DC bus and the second DC bus, with their respective sections, also remain within this zone. A section therefore does not extend beyond one zone. Thus, autonomous areas can be established within a floating facility, which remain operational even in the event of failure or damage to one of the zones of the floating facility.

[0065] In one embodiment of the power supply system, the floating facility has at least two longitudinal zones and at least two transverse zones, with two sections of at least one DC bus being located in the same transverse zone and also in different longitudinal zones. For example, faults occurring on one side of a ship can be limited with respect to their impact on the electrical power supply. The longitudinal zone is limited, for example, by a longitudinal bulkhead. The transverse zone is limited, for example, by a transverse bulkhead.

[0066] According to the invention, at least one of the DC voltage buses has a switching device (switch). The switching device, which operates mechanically and / or electrically via semiconductors, serves to disconnect or connect sections of the respective buses.

[0067] The triggering of the switching device for disconnection or connection can occur due to switching commands that are generated due to an electrical condition and / or due to switching commands that are generated due to events in a zone (e.g. water ingress, fire, etc.).

[0068] In one embodiment of the power supply system, the switching device in the DC bus is a fault disconnector, which disconnects the bus, in particular in the event of a short-circuit fault. Due to this function, the fault disconnector can also be referred to as a short-circuit switch. The switching device separates two zones, in particular. The switching device is, for example, a high-speed switch that enables the safe separation of sections of a bus. This means that a short circuit in one zone can be limited to that zone. Other zones remain largely unaffected by a short circuit in one of the numerous zones. This makes it possible to avoid shutting down and restarting the power supply in the event of a short circuit. The probability of a blackout for the entire floating facility can thus be reduced.

[0069] In a method for operating such an energy supply system of a floating facility, the floating facility having a first zone and a second zone, the floating facility having a first DC bus for a first DC voltage and a second DC bus for a second DC voltage, the floating facility having a first energy source and a second energy source, electrical energy is transferred from the first zone to the second zone or from the second zone to the first zone. For example, zones can be supplied with electrical energy regardless of whether they have an energy source.

[0070] In a method for operating an energy supply system for a water-based facility, having a first DC voltage bus for a first DC voltage and a second DC voltage bus for a second DC voltage, having a first energy source, wherein the first energy source has a generator system which has a first winding system for feeding the first DC voltage bus and which has a second winding system for feeding the second DC voltage bus, a first voltage is generated by means of the first winding system and a second voltage is generated by means of the second winding system, wherein the second voltage is lower than the first voltage, wherein a diesel engine or a gas turbine is used to drive the generator system. This and other methods can be supplemented and / or combined by further embodiments.

[0071] In one embodiment of the method, the supply from the first winding system or the supply from the second winding system is blocked. For example, on a cruise ship in a port, its hotel load can be served by just one winding system. The switch to or at the MV system (MV bus) can thus be opened if only power is needed for the LV bus.

[0072] In a method for operating an energy supply system for a water-based facility, having a first DC voltage bus for a first DC voltage and a second DC voltage bus for a second DC voltage, with a first energy source having at least two or at least three feeding electrical connections to the DC voltage buses, wherein at least one of the DC voltage buses has sections, the DC voltage buses are supplied with electrical energy. The feeding electrical connections have, for example, switches for disconnecting or closing the connection. In this way, for example, faulty areas (e.g., due to a short circuit) of the energy supply system can be separated from correctly functioning areas.

[0073] In one embodiment of the method, an energy supply system described here is used in carrying out the method.

[0074] In one embodiment of at least one of the methods, in the event of a fault, e.g. short circuit, earth fault, water ingress, fire, at least one of the DC buses is separated in a zone depending on the bulkhead, e.g. zone-dependent.

[0075] In one embodiment of at least one of the methods, in the event of a fault, a bulkhead is closed and at least one of the DC buses is disconnected depending on the bulkhead. This allows, in particular, the fault to be limited to a single zone.

[0076] In one embodiment of at least one of the methods, a first energy management system is carried out for at least the first zone and a second energy management system is carried out for at least the second zone. For example, each zone that has an energy source can have energy management through an energy management system, wherein the energy management systems of different zones can be connected to one another via data technology. In particular, a master energy management system can be defined which controls and / or regulates the energy flow between the zones that are managed by the individual energy management systems. A wired or radio-based transmission system can be used for data transmission. The radio-based transmission system can better manage disruptions that occur, for example, due to mechanical damage within a zone.

[0077] In one embodiment, only one energy management system is present, with each zone being able to operate independently in the event of a fault, even if the higher-level energy management system fails. For this purpose, each zone has at least one autonomous automation system.

[0078] In one embodiment of at least one of the methods, it can be used with any of the energy supply system configurations and combinations described here. The high flexibility of the method and the energy supply system enables flexible operation of the floating facility.

[0079] The power supply system described here can be used to implement a network architecture for high-performance ship-on-board networks with at least two voltage levels. In DC networks, the electrical energy is rectified and distributed via the common DC bus. Large AC consumers, as well as small ones such as main and auxiliary drives, are fed from the DC bus via inverters. AC sub-networks require an inverter and a transformer. As with a conventional AC main network, the voltage can be selected using the transformer's transformation ratio. The frequency can be adjusted using the inverter, independently of the generator speed. The use, and in particular the increased use, of DC buses can avoid the problems existing in AC networks relating to the high weight of the transformers and different frequencies of the networks in relation to the generator.When using a DC network architecture with at least two DC voltage levels (medium voltage (MV) and low voltage (LV)), the need for grid frequency transformers, e.g. for 50 Hz or 60 Hz, is reduced. The network architecture is characterized in particular by at least two DC bus systems (LV and MV), which can be designed as a closed bus. These DC ring buses are made possible in particular by the use of a very fast semiconductor switch for LV and MV to ensure the integrity of the individual bus sections in the zones in the event of a fault. This prevents faulty bus sections from leading to failures in other bus sections. The integration of an LV DC ring bus in addition to an MV ring bus enables the connection of decentralized energy storage systems to the LV DC ring bus and the use and distribution of the energy via the closed bus.In this case, decentralized energy storage systems primarily represent secondary energy sources. The use of multiple closed DC ring buses also enables better power distribution and / or energy sharing between the ring buses at different voltage levels. One option for connecting the different voltage levels is via a DC / DC converter. Another option is to supply the other DC ring bus via a transformer and rectifier on the AC side of the generator, while the DC ring bus with the higher power / higher voltage is supplied directly via a rectifier. If energy storage devices are connected to the low-voltage DC ring bus, the rectifier of the low-voltage ring bus can also be designed as an active inverter to enable energy flow in both directions.Feeding the generator via rectifiers or controlled rectifiers also enables a higher frequency of the generator output voltage, which reduces the required transformer in weight and dimensions.

[0080] In one embodiment of the energy supply system, a generator has at least two voltage levels. This allows further optimization of the system and avoids the need for a heavy transformer. By using generators with at least two voltage levels, a first voltage level and a second voltage level can be supplied. This particularly applies to the first DC voltage bus and the second DC voltage bus, which are each connected to the generator via rectifiers. This avoids the multiple conversion of energy as in AC networks. Arrangements that cover the upper and second voltage levels are sensible, since the power in the second and subsequent lower voltage levels continually decreases.

[0081] In a further embodiment, the rectifier on the second DC bus can also be designed as an active rectifier, allowing energy flow in both directions and / or also being capable of forming a network. This allows energy to be transported from the second DC bus, operated as a low-voltage bus, via the stationary, non-rotating generator to the first DC bus, operated as a medium-voltage bus.

[0082] In one design of the power supply system, the generator frequency can be freely selected within certain limits. When using generators with separate windings, different frequencies for the different voltages are also possible. The frequencies and other machine parameters influence the stability of the associated DC network. The two voltage levels are fed independently of each other by different generator windings or active components. It is irrelevant whether the active components are mounted in a housing on one shaft or in a tandem arrangement. Operation at two shaft ends is also possible.

[0083] In one embodiment of the power supply system, the active part length of the generator is shortened. This allows a generator to have two different active part lengths, for example. This is achieved, for example, through the use of new manufacturing technologies such as 3D printing. Potential savings can be achieved, for example, in the area of ​​the winding heads. This also makes it possible to use generators that do not increase in length, or only increase insignificantly, despite having several windings arranged one behind the other.

[0084] A new network architecture for ships with large on-board power and / or hotel services (e.g., cruise ships, navy (new classes with increased electrical power requirements in addition to propulsion power, FPSO; FSRU; ...)) enables efficient power supply by integrating multiple closed DC ring buses at different voltage levels. The increased use of DC buses enables the reduction of grid distribution transformers, e.g., 50Hz or 60Hz, which are required for AC grids.

[0085] Based on one of the described power supply system designs, the floating facility can eliminate AC / DC / AC conversion at the upper voltage level and simplify DC / AC / DC conversion between the voltage levels. If the sub-grid, i.e., the grid with a lower voltage, is a DC grid, the frequency of the supplying AC voltage can be optimally selected.

[0086] In one embodiment, the use of multiple DC ring buses with different voltage levels can be ensured by fast-switching semiconductor switches, enabling more optimal and reliable load distribution between the buses and more optimal distribution and use of energy storage between the individual zones. The loads on the second and lower voltage levels can be supplied with a fixed, freely assignable frequency that is independent of the speed of the diesel generators, even if the upper voltage level operates at a variable frequency.

[0087] In conventional grids, such as those used on cruise ships, the distribution transformers for the second voltage levels are designed redundantly. For example, if the hotel's power output is 10 MW, the total installed power of the distribution transformers is at least 20 MW. Due to additional safety features and taking simultaneity factors into account, this value increases significantly to between 25 MW and 30 MW. However, the generators connected to the first voltage level only need to provide a total of 20 MW for the second voltage level.

[0088] The various described energy supply systems and waterborne facilities, as well as the described processes, can be combined in a variety of ways. This allows the corresponding system, facility, or process to be adapted, for example, for use in a cruise ship, a crane ship, an oil platform, etc.

[0089] In one embodiment of the energy supply system, it has an electric shaft. This is an electric drive solution in which at least one generator and at least one drive motor are coupled to one another without an intermediate converter or power converter. In such a drive solution, one or more variable-speed drive motors (i.e. the motors for driving the propellers) are operated directly with the voltage of variable amplitude and variable frequency generated by one or more variable-speed generators, without an intermediate converter or power converter. Such generators can also feed at least one of the DC voltage buses via a rectifier. With an electric shaft, the control and / or regulation of the motors and thus of the propulsion units is thus carried out indirectly by controlling and / or regulating the internal combustion engines for driving the generators.The drive motors are electrically coupled to the generators, i.e. a rotary movement of the generators causes a corresponding proportional rotary movement of the electric drive motors. The function of a mechanical shaft is thus simulated with the help of electrical machines. This type of drive solution is referred to as an electric shaft. It is also possible to extract electrical energy from the electric shaft via an on-board power converter, i.e. an on-board power converter converts the voltage of variable amplitude and variable frequency generated by the generator(s) into a voltage of constant amplitude and constant frequency for an on-board power system. The LV DC bus, for example, is assigned to the on-board power system and therefore has this.An electrical drive shaft comprises, for example, at least one variable-speed generator for generating a voltage with variable amplitude and variable frequency, and at least one variable-speed drive motor supplied with this voltage. The at least one generator has, in particular, a superconductor winding, in particular a high-temperature superconductor (HTS) winding. The superconductor winding can be a stator winding or a rotating rotor winding of the generator. A generator with a superconductor winding has, in particular, a significantly larger magnetic air gap between the rotor and stator compared to a conventional generator without a superconductor winding. This is primarily due to the fact that the superconductor is cooled by a vacuum cryostat or a similar cooling device, the wall of which runs in the air gap.The relatively large magnetic air gap means that the generator has a significantly lower synchronous reactance than a conventional generator. This means that, for the same electrical output, an HTS generator has a significantly stiffer current-voltage characteristic curve compared to a conventional generator. This prevents the voltage generated by the generator from dropping during load applications or surges. Voltage and frequency fluctuations in the electrical shaft can be reduced as a result. This eliminates the need for complex control of the electrical shaft to stabilize the traction network voltage and the speed of the drive motors or propulsion unit.If the at least one drive motor also has a superconductor winding, in particular a high-temperature superconductor (HTS) winding, it can be designed to be very powerful and torque-intensive despite its compact size, which is particularly important for the use of a watercraft in ice. In one embodiment, the superconductor winding is a rotating rotor winding. In this case, the surface to be cooled is smaller than can be maintained with a superconductor stator winding. In the case of multiple variable-speed generators, each generating a voltage with variable amplitude and variable frequency, the electrical shaft also includes a generator synchronization device for synchronizing the amplitude, frequency, and phase of the voltages generated by the generators.

[0090] In one embodiment of the energy supply system, at least one generator and / or one motor has HTS technology.

[0091] In one embodiment of the power supply system, an interface for a port power supply is provided. This interface is, for example, a connection to the MV DC bus and / or a connection to the LV DC bus and / or a connection to a three-phase system of the power supply system.

[0092] The invention is described below by way of example with reference to the figures. The same reference numerals are used for similar units. It shows: FIG 1 shows a ship with a first subdivision into zones, FIG 2 shows a ship with a second subdivision into zones, FIG 3 shows a ship with a third subdivision into zones, FIG 4 shows a first circuit diagram for a power supply system, FIG 5 shows a second circuit diagram for a power supply system, FIG 6 shows a third circuit diagram for a power supply system, FIG 7 shows a fourth circuit diagram for a power supply system, FIG 8 shows a fifth circuit diagram for a power supply system, FIG 9 shows a sixth circuit diagram for a power supply system, FIG 10 shows a seventh circuit diagram for a power supply system, FIG 11 shows winding systems, FIG 12 shows an equivalent circuit, FIG 13 shows an eighth circuit diagram for a power supply system, FIG 14 shows a ninth circuit diagram for a power supply system, FIG 15A shows part A of a tenth circuit diagram for a power supply system, and FIG 15B shows part B of the tenth circuit diagram for a power supply system

[0093] The representation according toFIG 1 shows a ship 101 with a first subdivision into zones. Shown are a first zone 31, a second zone 32, a third zone 33, and a fourth zone 34. These zones are delimited by bulkheads 71. A further zone is defined, for example, by a watertight deck 70.

[0094] The representation according to FIG 2 shows a ship 101 in a top view, as well as a plan view, with a second subdivision into zones 31 to 39. The zones can also be divided into longitudinal zones 102 and transverse zones 103. A power supply system 100 extends across the zones. The power supply system has a first DC bus 11 and a second DC bus 12. The DC buses 11 and 12 extend differently across the zones. In a further embodiment, the partitioning in the longitudinal zones can also be omitted. However, this is not shown.

[0095] The representation according to FIG 3 shows a ship 100 with a third subdivision into zones 31 to 39, wherein zones 37, 38, and 39 are central zones within the ship and are bordered by further zones on the port and starboard sides, respectively. The energy supply system 100 has a first DC bus 11 and a second DC bus 12, wherein the first DC bus 11 is, for example, a medium-voltage bus and the second DC bus 12 is a low-voltage bus.

[0096] The representation according to FIG 4 shows a first circuit diagram for an energy supply system 100. The illustration has a first zone 31, a second zone 32 and a third zone 33. The zones are marked by zone boundaries 105. In the first zone 31 there is a first energy source 21. The first energy source 21 has a diesel engine 1 and a generator 5. In the second zone 32 there is a second energy source 22. The second energy source 22 has a diesel engine 2 and a generator 6. A first DC voltage bus 11 extends into the first zone 31 as well as into the second zone 32 and also into the third zone 33, thereby forming a ring bus. A second DC voltage bus 12 extends into the first zone 31 as well as into the second zone 32 and also into the third zone 33, thereby also forming a ring bus. The buses can also be designed as non-ring buses, although this is not shown.The first DC bus 11 is located in a first DC voltage level 13 or provides it. The second DC bus 12 is located in a second DC voltage level 14 or provides it. The first DC bus 11 can be divided into sections 61 to 66. The division is achieved using MV switching devices 81. The first DC bus 11 is therefore at a medium voltage. The second DC bus 12 can also be divided into sections 61 to 66. The division is achieved using LV switching devices 80. The second DC bus 12 is therefore at a low voltage. A three-phase bus (AC bus) 15 can be fed via the second DC bus 12. Batteries 91 are also connected to the second DC bus 12. Motors (asynchronous motors, synchronous motors and / or PEM motors) 85 are shown as consumers for the second DC voltage bus 12, which can be operated via inverters 93.To supply DC voltage buses 11 and 12, a first supply 51, a second supply 52, a third supply 53, and a fourth supply 54 are provided. These supplies are electrical connections for the DC buses. The generator 5 supplies the first section 61 via the first supply 51, wherein the first supply 51 has a rectifier 95 and a switch 84. The generator 5 supplies the fourth section 64 of the first DC voltage bus 11 via the second supply 52. ​​The second supply 52 in the first zone 31 also has a rectifier 96 and a switch 84. The third supply 53 has a medium-voltage transformer 105 and a rectifier 97. The third supply 53 feeds the first section 61 of the second DC bus 12. The fourth supply 54 has a switch 84 and a DC / DC converter 104.Thus, the fourth feed 54 connects a section 64 of the first DC bus 11 to a section 61 of the second DC bus 12. In the second zone 32, the generator 6 is connected to the DC buses 11 and 12 in the same way via the feeds 1 to 4 as described in the first zone 31.

[0097] The representation according to FIG 5 shows a second circuit diagram for a power supply system 100. In comparison to FIG 4 an enlarged section is shown. In contrast to FIG 4 is in FIG 5 To illustrate a variation, a generator 5 is shown which has only three feeding electrical connections 51, 53 and 54 to the DC buses 11 and 12.

[0098] The representation according to FIG 6 shows a third circuit diagram for a power supply system 100. It is shown that ship propulsion motors 106, 107, each of which is intended to drive a propeller 108, can be connected as consumers to the first DC voltage bus 11. Motor 106 is doubly fed via inverters 93 and 94. Motor 107 is singly fed.

[0099] It is shown that additional consumers can be connected to the DC bus 11 auxiliary drives, e.g. compressor drive 207.

[0100] It is shown that a three-phase network can be generated via an active inverter, e.g. a modular multilevel converter (MMC) with / without filter 208, which is connected to the DC bus 11.

[0101] It is shown that different variants are planned for energy supply.

[0102] As one embodiment, a generator 201 with an associated rectifier is shown.

[0103] As one embodiment, a generator 200 with at least two winding systems and two associated rectifiers is for use at power levels that cannot be realized for one rectifier.

[0104] As one embodiment, these rectifiers can also feed a generator with a winding system (not shown) in parallel.

[0105] As one embodiment, the generator 202 supplies the first DC voltage bus 11 via a rectifier and the second DC voltage bus 12 via a transformer 205 and a rectifier 206.

[0106] As one embodiment, a feed 204 is shown as a connection to land, shore connection.

[0107] As one embodiment, a connection of the DC bus 11 to the DC bus 12 with a DC / DC converter 209 is shown.

[0108] One embodiment of this DC / DC converter is shown as a three-pole 210. In addition to the DC bus 12 and 11, a battery 211 and / or another DC bus can also be connected.

[0109] In a further embodiment, this three-pole can also be designed as a multi-pole.

[0110] The representation according to FIG 7 shows a fourth circuit diagram, where two motors are connected to the propellers 108 via a shaft system 43. Here, too, the power is supplied via the DC bus 11, but via different sections 61 and 64 of this bus.

[0111] The representation according to FIG 8 shows a fifth circuit diagram, showing four diesel-powered energy sources 21 to 24 as well as alternative energy sources. A wind turbine 25 can be an energy source. A shore connection 26 can be an energy source, as can a photovoltaic system 27.

[0112] The representation according to FIG 9 shows a generator system 10 with two generators 7 and 8, which are rigidly coupled via a shaft system 43. Here, generator 7 has a low-voltage winding system, and generator 8 has a medium-voltage winding system. A low-voltage direct current bus 12 is fed by generator 7, and a medium-voltage direct current bus 11 is fed by generator 8.

[0113] The representation according to FIG 10 shows a multi-winding system generator 9 which has at least two winding systems, a first winding system for a medium voltage and a second winding system for a low voltage. The first winding system supplies the first DC bus 11 at the medium voltage level (MV) via a first supply electrical connection 51. The second winding system supplies the second DC bus 12 at the low voltage level (LV) via a further supply electrical connection 53.

[0114] The representation according to FIG 11 schematically shows the possible arrangements of windings in the stator of a multi-winding system generator. In a first variant, the LV windings can be arranged in sections in adjacent slots 44, and the MV windings can be arranged in sections in adjacent slots 45. In a second variant, the MV windings and the LV windings can be arranged in common slots 46. In a third variant, the MV windings and the LV windings can be arranged alternately in slots 24 and 48.

[0115] The representation according to FIG 12 shows an equivalent circuit diagram for a D-axis of a multi-winding system generator.

[0116] The representation according to FIG 13 shows an eighth circuit diagram for an energy supply system 100, wherein it is shown how the first DC voltage bus 11 can be fed by the generator 6 via two different sections 61 and 64 and how the second DC voltage bus 12 can also be fed by this generator 6 via two different sections there too.

[0117] The representation according to FIG 14 shows how two sections 61 and 62 of the first DC bus 11 in different zones 31 and 32 can be fed by a generator in one zone (generator 5 in zone 31 and generator 6 in zone 32) and how this also applies to the second DC bus 12.

[0118] The representation according to FIG 15is divided into two sub-figures 15A and 15B. Both combine an energy supply system 100, which has four diesel generators 1, 2, 3, and 4 as part of the energy sources 21, 22, 23, and 24, and expresses that the energy supply system can be expanded or modified almost arbitrarily according to the requirements of the waterborne facility. Because the waterborne facility is located, for example, on a ship or an oil rig, it is operated entirely or predominantly as an island network.

Claims

1. Power supply system (100) for a water-bound device (101), having a first DC voltage bus (11) for a first DC voltage and having a second DC voltage bus (12) for a second DC voltage, having a first power source (21), wherein the first power source (21) has a generator system which comprises a first winding system (41) for supplying the first DC voltage bus (11) and which comprises a second winding system (42) for supplying the second DC voltage bus (12), having a second power source (22), characterized in that the water-bound device (101) comprises a first zone (31) and a second zone (32), wherein the first power source (21) is provided in the first zone (31) for supplying at least one DC voltage bus (11, 12) of the at least two DC voltage buses (11, 12) and wherein the second power source (22) is provided in the second zone (32) for supplying at least one DC voltage bus (11, 12) of the at least two DC voltage buses (11, 12), wherein, in particular, the power supply system (100) is at least partially divided in a manner dependent on zone, wherein the first DC voltage bus (11) can be divided into sections (61 to 66) and division is performed by means of MV switching devices (81), wherein the first DC voltage bus (11) is at a medium voltage, and in that the second DC voltage bus (12) can also be divided into sections (61 to 66) and division is performed by means of LV switching devices (80), wherein the second DC voltage bus (12) is at a low voltage.

2. Power supply system (100) according to Claim 1, wherein the first winding system (41) is designed for a first voltage and the second winding system (42) is designed for a second voltage, wherein the first voltage is greater than the second voltage.

3. Power supply system (100) according to Claim 1 or 2, wherein the first winding system (41) is electrically connected to the first DC voltage bus (11) for the transformer-free supply thereof.

4. Power supply system (100) according to one of Claims 1 to 3, wherein the second winding system (42) is electrically connected to the second DC voltage bus (12) for the transformer-free supply thereof.

5. Power supply system (100) according to one of Claims 1 to 4, wherein the generator system comprises a first generator (7) having the first winding system and a second generator (8) having the second winding system, wherein the first generator (7) and the second generator (8) can be driven by means of a joint shaft system (43).

6. Power supply system (100) according to one of Claims 1 to 4, wherein the generator system is a multi-winding system generator (9), wherein the stator of the multi-winding system generator (9) comprises the first winding system and the second winding system.

7. Power supply system (100) according to Claim 6, wherein the multi-winding system generator (9) has slots which affect the first winding system and the second winding system.

8. Power supply system (100) according to one of Claims 1 to 7, wherein at least one of the DC voltage buses (11, 12) may be in the form of a ring bus.

9. Power supply system (100) according to one of Claims 1 to 8, wherein the first DC voltage bus (11) is provided for supplying the second DC voltage bus (12).

10. Method for operating a power supply system (100) according to one of the preceding claims for a water-bound device (101), wherein a first voltage is generated by means of the first winding system (41) and a second voltage is generated by means of the second winding system (42), wherein the second voltage is lower than the first voltage, wherein a diesel or a gas turbine is used to drive the generator system, characterized in that an MV switching device (81) disconnects the first DC voltage bus (11) or an LV switching device (80) disconnects the second DC voltage bus (12).

11. Method according to Claim 10, wherein the supply by the first winding system (41) or the supply by the second winding system (42) is prevented.