Filter arrangement for an electrical power system

Abstract

The invention relates to a filter arrangement (200, 300, 400) for an electrical power system (440), in particular an electrical power generation system, comprising a first electrical connection (206, 306) configured for electrically connecting the filter arrangement (200, 300, 400) to a power transmission conductor (208, 308, 408), a second electrical connection (210, 310) in the form of a ground connection, wherein the filter arrangement (200, 300, 400) is formed from a first sub-circuit (202, 302) consisting of a first inductive component (226, 326) connected in parallel with a capacitive component (212, 312), a second sub-circuit (204, 304) consisting of a second inductive component (216, 318) connected in parallel with a resistive component (218, 318). 316), wherein the first sub-circuit (202, 302) and the second sub-circuit (204, 304) are between the first electrical terminal (206, 306) and the second electrical terminal (210,310) are connected in series.

Description

[0001] The invention relates to a filter arrangement for an electrical power system, in particular an electrical power generation system. Furthermore, the invention relates to a power system and the use of the filter arrangement in a power system.

[0002] (High-)power systems with at least one power generator and / or at least one power consumer and / or one energy transmission conductor (e.g., high-voltage cables (e.g., overhead lines) and / or transformers) are known from the prior art. The power system can be a power or energy generation system designed to generate electrical energy based on a renewable energy source. For example, the power generation system can be a wind farm and / or a photovoltaic park. A wind farm, especially an offshore wind farm, preferably comprises a plurality of wind turbines and, in particular, at least one substation or converter station (e.g., offshore substation). A power system with a power consumer can be, for example, an electrolyzer plant, but also another type of consumer.

[0003] A power system is characterized in particular by the fact that it includes an electrical grid connection, preferably formed by at least one electrical power transmission conductor. An electrical grid connection is provided for electrically connecting or coupling the power system (or the at least one power generator and / or power consumer of the power system) to an electrical grid, in particular a distribution grid. Specifically, the electrical grid connection allows for the injection of electrical power generated by the power system and / or the receipt or withdrawal of electrical power by the power system.

[0004] A constant concern in the state of the art is the safe and, in particular, stable operation of the power system, but also especially of the distribution network. A problem in power systems is the occurrence of unwanted harmonics. Harmonics can be caused, for example, by nonlinear loads in the power system and / or the distribution network. Examples of loads that can cause harmonics include power electronic converters, arc furnaces, etc. Harmonics can cause various problems, such as additional power losses, interference with control and communication systems, and so on.

[0005] Furthermore, (unwanted) resonant or oscillatory circuits can form in power systems. In particular, it has been recognized that unwanted oscillatory circuits can form in a power system with a transformer and a power transmission conductor, for example in the form of a medium-voltage cable or a high-voltage cable with a cable length of 5 km or more.

[0006] To avoid harmonics and / or unwanted resonant circuits, filter arrangements, particularly harmonic filters, are used in such power systems in the prior art. A schematic view of an example of such a prior art filter arrangement is shown in the Fig. Figure 1 shows the filter arrangement 100 shown, in particular a so-called C-filter 120 with an additional reactive power compensator 122.

[0007] The C-filter 120 has a first electrical connection 106, which is configured for electrically connecting the C-filter 120 to a power transmission conductor 108. Furthermore, the C-filter 120 has a second electrical connection 110 in the form of a ground connection 110, which can be connected to ground. The C-filter 120 consists of a first sub-circuit 102 with a first capacitive element 112 in the form of a first capacitor and a second sub-circuit 104. The second sub-circuit 104 consists of a resistive element 118, which is connected in parallel to a second capacitive element 114 and a first inductive element 116, which is connected in series with the second capacitive element 114. The second capacitive element 114 is a capacitor and the first inductive element 116 is an inductor.

[0008] The reactive power compensator 122 comprises at least one second inductive component 124 in the form of a coil connected in parallel with the C-filter 120.

[0009] Therefore, at least five components are required in the state-of-the-art filter arrangement 100. In a power system in the form of a wind farm, which is connected to a distribution network via the power transmission line, for example, the components can have the following exemplary values: First capacitive component 112: C1 = 12.78 µF; First inductive component 116: L1= 99 mH; Resistance element 118: R1 = 150 ohms; Second capacitive component 114: C2 = 102µF; Second inductive component 124: L2 = 792 mH.

[0010] Disadvantages of the described state-of-the-art filter arrangement, as well as other similar known filter arrangements, are the capacitive properties of the C-filter at the mains frequency and the power losses. In some applications, e.g., in power systems with long cables or corresponding distribution networks, the reactive power of the C-filter is not required and must therefore be compensated by an additional reactive power compensator. This leads to a significantly increased complexity and corresponding costs.

[0011] While the C-filter has the lowest power loss among the filters known from the prior art, it also exhibits capacitive properties at mains frequency that must be compensated, as described.

[0012] In most power systems, the 5th and 7th harmonics are particularly dominant. High-pass filters have significant power losses for these harmonics, and C-filters have a large resonant capacitor.

[0013] Furthermore, it should be noted that in practice, it is common to connect power systems via overhead power lines. A C-filter, with its capacitive behavior, is advantageous in such overhead lines. However, this advantage is often negated as the proportion of other cable types (e.g., underground cables, submarine cables) increases.

[0014] Therefore, the invention is based on the objective of providing a filter arrangement in which the disadvantages of the prior art are at least reduced and which is in particular less complex and at the same time at least reduces the power losses, in particular entails almost no power losses.

[0015] The problem is solved according to a first aspect of the invention by a filter arrangement according to claim 1 for an electrical (high-)power system, in particular an electrical power generation system. The filter arrangement comprises a first electrical connection. The first electrical connection is configured for electrically connecting the filter arrangement to a power transmission conductor. The filter arrangement comprises a second electrical connection, in particular in the form of a ground connection. The filter arrangement comprises a first sub-circuit. The first sub-circuit consists of a first inductive component connected in parallel with a capacitive component. The filter arrangement comprises a second sub-circuit. The second sub-circuit consists of a second inductive component connected in parallel with a resistive component.The first sub-circuit and the second sub-circuit, in particular only the first sub-circuit and the second sub-circuit, are connected in series to each other between the first electrical terminal and the second electrical terminal.

[0016] By providing a filter arrangement according to the invention that consists of two sub-circuits with only four components, in contrast to the prior art, the disadvantages of the prior art are at least reduced, and in particular, a less complex filter arrangement is provided. Specifically, at least one second capacitive component with a high capacitance can be omitted in the filter arrangement according to the invention. Costs can be reduced. Costs can also be reduced because the filter arrangement requires less floor space. This is particularly advantageous for offshore power systems.

[0017] Furthermore, the power losses in the filter arrangement according to the invention can be lower compared to known filter arrangements, including, for example, the described C-filter. In contrast to known harmonic filters, such as the C-filter, the filter arrangement according to the invention does not involve any reactive power exchange with the connected distribution network. An additional reactive power compensator is therefore unnecessary. In particular, no power losses occur for the 5th and 7th order harmonics in the filter arrangement according to the invention. As already described, a large resonant capacitor is also not required, thus saving both costs and space.

[0018] The filter arrangement according to the invention is used in particular for filtering at least one harmonic in or at a power system. The power system according to the invention is in particular a high-power system. In the present context, an (electrical) power system means in particular a power system with a minimum generated power and / or drawn power of 0.1 MW and / or a maximum generated power and / or drawn power of 2 GW.

[0019] The power system according to the invention can preferably be an energy generation system. In particular, the energy generation system is an energy generation system or power generation system based on at least one renewable energy source (e.g., solar energy, wind energy, etc.). Alternatively or additionally, the power system can be an energy consumption system or power consumption system, in particular in the form of a hydrogen production plant or the like.

[0020] The power system preferably comprises at least one power device. Preferably, the power system comprises a plurality of power devices, which can be electrically interconnected, for example. The at least one power device can be a power generator or a power generator device and / or a power consumer or a power consumer device. In particular, two or more power generators and / or two or more power consumers can be provided in the power system.

[0021] The power system may, in particular, include and / or be connected to at least one power transmission conductor or power cable. The power transmission conductor serves, in particular, to connect the power system (or the at least one power device) to an electrical distribution network. The electrical distribution network is, in particular, a (public) extra-high-voltage network (e.g., between 110 kV and 380 kV), a (public) high-voltage network (e.g., between 50 kV and 110 kV), and / or a (public) medium-voltage network (e.g., between 1 kV and 50 kV). In principle, the power system can be a voltage system between 0.1 kV and 750 kV.

[0022] The filter arrangement can be a single-phase filter arrangement or a multi-phase filter arrangement (e.g., a three-phase filter arrangement).

[0023] The filter arrangement is, in particular, a harmonic filter arrangement. The filter arrangement comprises two electrical connections, specifically exactly two electrical connections. In other words, the filter arrangement specifically comprises no more than two electrical connections. A first electrical connection of the filter arrangement serves to electrically connect the filter arrangement to the power transmission conductor. The second electrical connection is, in particular, a ground connection, specifically electrically connectable to a ground potential. The ground connection may be provided in three-phase filter arrangements. In some parts of the Japanese power grid, for example, it may be necessary not to connect the second connection to ground. The second electrical connection may be, for a multi-phase filter arrangement (e.g., a three-phase filter arrangement): 1 directly connected to the Earth; 2- indirectly connected to the earth (via an impedance); 3- not connected to the Earth.

[0024] Furthermore, the filter arrangement comprises a first sub-circuit and a second sub-circuit connected between the first and second terminals. In this context, this means in particular that the filter arrangement consists solely of the first and second sub-circuits. In other words, the filter arrangement does not include any further sub-circuits and / or other electrical components.

[0025] The first sub-circuit consists (only) of a first capacitive component and a first inductive component. In other words, the first partial application does not include any further electrical components. The first capacitive component is, in particular, a capacitor. The first capacitive component and the first inductive component are connected in parallel to each other.

[0026] The second sub-circuit consists (only) of a resistive element and a second inductive element. In other words, the second application does not include any further electrical components. The resistive element is, in particular, a resistor. The resistive element and the second inductive element are connected in parallel.

[0027] In variants of the invention, at least one switch can be provided between the first sub-circuit or the second sub-circuit. At least one switch can also be arranged between the first terminal and the first sub-circuit or the second sub-circuit. Furthermore, at least one switch can be arranged between the second terminal and the first sub-circuit or the second sub-circuit.

[0028] The first sub-circuit is furthermore connected in series with the second sub-circuit between the first electrical connection and the second electrical connection.

[0029] According to a preferred embodiment of the filter arrangement according to the invention, the first sub-circuit can be connected to the first electrical terminal. In this embodiment, the second sub-circuit can be connected to the second electrical terminal.

[0030] In an alternative embodiment of the invention, the first sub-circuit can be connected to the second electrical terminal. The second sub-circuit can be connected to the first electrical terminal.

[0031] According to another embodiment of the filter arrangement, the first inductive element can be a first coil and the second inductive element a second coil, which is particularly separate from the first coil. In other words, two separate coils can be provided, which can be electrically connected to each other via a wire or electrical connection. The first and second inductive elements can be implemented in a simple manner.

[0032] According to a preferred embodiment of the filter arrangement according to the invention, the first inductive element and the second inductive element can be formed by a common coil with a center tap. The first inductive element can be formed by a first winding of the common coil extending from a first terminal of the common coil to the center tap. The second inductive element can be formed by a second winding of the common coil extending from the center tap to the second terminal of the common coil. The two inductive elements can be implemented in a particularly compact manner.

[0033] According to a particularly preferred embodiment of the filter arrangement according to the invention, the filter arrangement can form a resonant circuit. The resonant circuit formed can be essentially formed by the first sub-circuit at a mains frequency (e.g., 50 Hz or 60 Hz) of the power system. In other words, the value of the first inductive component and the value of the first capacitive component are specifically matched to each other such that the first inductive component and the first capacitive component form a (desired) resonant circuit at the mains frequency of the power system.

[0034] The value of the (parallel) inductive component can be tuned to or around the mains frequency to achieve, for example, a desired reactive power balance and minimal power loss at the mains frequency. Finding a compromise between reactive power control within the system and filter losses can be advantageous. The oscillation can therefore occur at or around the mains frequency. The first oscillation can be generated by parallel connections at a lower frequency, and the second oscillation can be generated by series connections at a higher frequency.

[0035] Particularly preferably, according to a further embodiment of the filter arrangement, the resonant circuit can be configured, or the first inductive component and the first capacitive component can be matched, such that no fundamental current flows from the first electrical terminal of the filter arrangement to the second electrical terminal of the filter arrangement at the mains frequency. This further reduces the power loss in the filter arrangement according to the invention. In particular, virtually no power loss occurs. In other words, at the mains frequency, the resonant circuit acts like an open circuit, so that no fundamental current flows from the first electrical terminal of the filter arrangement to the second electrical terminal of the filter arrangement at the mains frequency.This can only apply if the first tuning frequency is chosen as the power frequency.

[0036] According to a further preferred embodiment of the filter arrangement according to the invention, the value of the first inductive component, the value of the second inductive component, and the value of the capacitive component (and in particular the value of the resistive element) can be matched to one another such that a defined (main) filter frequency is provided by the filter arrangement. The filter frequency is, in particular, the frequency that is filtered out by the filter arrangement. Especially above the mains frequency, the filter arrangement can have a lower impedance through appropriate tuning. Harmonic currents flow through the filter arrangement and are attenuated, in particular, by the resistive element. The tuning can be made, in particular, depending on the electrical characteristics of the power system, especially a transformer and the associated power transmission conductor.Harmonics can be filtered in a simple and safe way.

[0037] According to one embodiment, the first electrical connection may not include a switch. According to another embodiment of the filter arrangement according to the invention, the first electrical connection may include at least one switch. In variants of the invention, two switches may be provided. The capacitive component may be connected to the first switch, and the first inductive component may be connected to the second switch.

[0038] Another aspect of the invention is an electrical power system. The electrical power system comprises (as already described) at least one power device, comprising at least one power generator and / or at least one power consumer. The electrical power device is connected (indirectly or directly) to an electrical power transmission conductor. The electrical power system comprises at least one (previously described) filter arrangement (in particular according to claim 1). The first electrical connection of the filter arrangement is connected to the power transmission conductor.

[0039] The power system can include the power transmission line. Preferably, the power system can be an offshore power system. The power system is, in particular, a power generation system.

[0040] According to a preferred embodiment of the electrical power system, the electrical power system can be a wind farm. In particular, the power system can be an offshore wind farm. The wind farm can comprise, as power generators, a plurality of power generators in the form of wind turbines, especially offshore wind turbines. A wind turbine is configured to convert the kinetic energy of the wind into electrical energy. The generated electrical energy can be transmitted via the at least one power transmission conductor and, in particular, fed into a distribution network.

[0041] An offshore wind farm can comprise at least one converter station or substation, such as at least one offshore substation and / or at least one onshore substation. The majority of offshore wind turbines can be connected to the offshore substation via an internal power cable network (e.g., formed by power transmission conductors in the form of subsea power cables). The offshore substation can be connected to the onshore substation via at least one power transmission conductor in the form of a subsea power cable. The offshore substation (possibly together with the subsea power cable and / or the onshore substation) can provide an electrical connection to an electrical distribution network. Preferably, the substation can include at least one filter arrangement according to the invention.

[0042] Alternatively or additionally, the electrical power system can be a photovoltaic park, in particular an offshore photovoltaic park. The photovoltaic park can comprise a plurality of photovoltaic systems, preferably offshore photovoltaic systems, as power generators. A photovoltaic system is configured to convert solar energy into electrical energy. The photovoltaic park can be connected to the electrical distribution network via a converter station or substation and an energy transmission conductor, in particular in the form of a power cable. Preferably, the substation can include at least one filter arrangement according to the invention.

[0043] Alternatively or additionally, the electrical power system can be a hydrogen production plant, in particular an offshore hydrogen production plant. The hydrogen production plant, as a power consumer, can include at least one electrolyzer. An electrolyzer is designed to carry out water electrolysis based on supplied or drawn electrical energy or power, in particular from the electrical distribution network. It is understood that a hydrogen production system can include further electrically driven devices, such as compressors, water and / or hydrogen processing plants, nitrogen generators, etc.

[0044] In variants of the invention, a power system can be formed from at least one energy generation system and one energy consumption system, such as a (previously described) (offshore) wind farm and / or a (previously described) (offshore) photovoltaic park with a (previously described) (offshore) hydrogen production system.

[0045] According to a preferred embodiment of the electrical power system, the electrical power system can comprise at least one transformer. For example, the power system can comprise a previously described substation or converter station. The substation can include the at least one transformer. The at least one electrical power device can be (electrically) connected to the transformer. For example, a plurality of wind turbines and / or photovoltaic systems can be electrically connected to the transformer. The transformer can be electrically connected to the power transmission conductor (in the form of a medium-voltage cable or high-voltage cable). In particular, one end of the power transmission conductor can be (directly) connected to the transformer and the other end can be (directly or indirectly, for example via another substation) connected to a distribution network.

[0046] It has been recognized, in particular, that power transmission conductors in the form of cables, together with transformers, can form resonant circuits and thereby cause temporary overvoltages and amplify existing harmonic distortions, which can ultimately damage electrical components and disrupt the operation of the power grid. By electrically connecting the filter arrangement according to the invention to the power transmission conductor connected to the transformer, the risk of overvoltages and / or amplified harmonic distortions can be significantly reduced. In particular, the filter arrangement can be located together with the transformer at the substation. The operational reliability of a corresponding electrical power system can be further improved.

[0047] According to a further preferred embodiment of the electrical power system, the power system can comprise the energy transmission conductor, in particular in the form of a medium-voltage cable or high-voltage cable. The energy transmission conductor (or the corresponding cable) can have a length between 10 km and 200 km, preferably between 50 km and 100 km. Particularly in combination with a transformer, the operational safety problems described above can occur with such a long energy transmission conductor without a filter arrangement according to the invention. Alternatively or additionally, the energy transmission conductor (in particular the (entire) phase conductor) can have a conductor cross-section of between 50 mm². 2 and 2500 mm 2 .

[0048] A further aspect of the invention is the use of a previously described filter arrangement (according to claim 1) for filtering at least one harmonic in a previously described electrical power system (according to claim 8).

[0049] It should be noted that terms such as "first", "second", "further", etc. do not indicate a sequence, but serve in particular to distinguish between two elements (e.g., inductive components).

[0050] The features of the filter arrangements, performance systems, and uses can be freely combined. In particular, features of the description and / or the dependent claims, even by completely or partially circumventing features of the independent claims, can be independently inventive, either on their own or freely combined.

[0051] There are now numerous possibilities for designing and further developing the filter arrangement, the electrical power system, and the use according to the invention. Reference is made, on the one hand, to the claims subordinate to the independent claims, and on the other hand, to the description of exemplary embodiments in conjunction with the drawing. The drawing shows: Fig. 1. A schematic view of an example of a filter arrangement according to the state of the art, Fig. 2a a schematic view of an embodiment of a filter arrangement according to the present invention, Fig. 2b a schematic view of an embodiment of a filter arrangement according to the present invention, Fig. 2c a schematic view of an embodiment of a filter arrangement according to the present invention, Fig.3 a schematic view of a further embodiment of a filter arrangement according to the present invention, and Fig. 4 a schematic view of an embodiment of an electrical power system according to the present invention with an embodiment of a filter arrangement according to the present invention.

[0052] In the following, similar reference symbols are used for similar elements.

[0053] The Fig. Figure 2a shows a schematic view of an embodiment of a filter arrangement 200 according to the present invention. The filter arrangement 200 is particularly designed for use in or on an electrical power system (not shown), especially an electrical power generation system.

[0054] The filter assembly 200 comprises a first electrical connection 206 and a second electrical connection 210. In particular, the filter assembly 200 does not include any further electrical connections or terminals. As the Fig. As can be further seen from Figure 2, the first electrical connection 206 is configured for electrically connecting the filter arrangement 200 to a power transmission conductor 208. The power transmission conductor 208 is, in particular, a medium-voltage cable or a high-voltage cable. The second electrical connection 210 is preferably a ground connection (especially in the case of a three-phase filter arrangement) that can be connected to ground or ground potential. In the case of a single-phase filter arrangement, the connection to ground can also be omitted.

[0055] The filter arrangement 200 comprises a first sub-circuit 202 and a second sub-circuit 204. In particular, the filter arrangement 200 consists (only) of the first sub-circuit 202 and the second sub-circuit 204. The first sub-circuit 202 consists of a first inductive component 226 and a capacitive component 212. The capacitive component 212 is connected in parallel to the first inductive component 226. The capacitive component 212 is, in particular, a capacitor. The first inductive component 226 is, in particular, an inductor.

[0056] The second sub-circuit 204 consists of a second inductive component 216 and a resistive component 218. The resistive component 218 and the second inductive component 216 are connected in parallel. The second inductive component 216 is, in particular, another (separate) coil.

[0057] The first sub-circuit 202 and the second sub-circuit 204 are connected in series between the first electrical terminal 206 and the second electrical terminal 210. Specifically, only the aforementioned sub-circuits 202 and 204 are connected in series between the first electrical terminal 206 and the second electrical terminal 210. In variants of the invention, a switch may be arranged between the first and the second sub-circuit.

[0058] The components can (especially in a power system in the form of an offshore wind farm) exhibit the following exemplary values: Capacitive component 212: C1 = 12.78 µF; First inductive component 216: L1 = 99 mH; Resistance element 218: R1 = 150 ohms; Second inductive component 226: L2 = 792 mH.

[0059] In comparison to the filter arrangement after Fig. 1 It is immediately apparent that in the filter arrangement 200 according to the invention, a second capacitive component as well as a reactive current compensator can be dispensed with.

[0060] In the present embodiment, the first sub-circuit 202 is connected to the first electrical terminal 206 and the second sub-circuit 204 is connected to the second electrical terminal 210. In other variants of the invention, the second sub-circuit can also be connected to the first electrical terminal and the first sub-circuit to the second electrical terminal.

[0061] The filter arrangement 200 can, in particular, form a resonant circuit. The resonant circuit formed can be created by the first sub-circuit 202 at a mains frequency (e.g., 50 Hz or 60 Hz) of the power system. The values ​​of the first inductive component 226 and the first capacitive component 212 can be matched such that the first inductive component 226 and the first capacitive component 212 form a resonant circuit at the mains frequency of the power system. The resonant circuit is, in particular, configured or tuned such that no residual current can flow from the first electrical terminal 206 of the filter arrangement 200 to the ground terminal. Especially at the mains frequency, the resonant circuit acts like an open circuit, so that no residual current flows from the first electrical terminal 206 of the filter arrangement 200 to the second electrical terminal 210 of the filter arrangement at the mains frequency.In variants of the invention, the filter arrangement can be tuned not exactly to the specified mains frequency, but around this value (e.g. ±20%).

[0062] Furthermore, the values ​​of the first inductive component 226, the second inductive component 216, and the capacitive component 212 (and in particular the value of the resistive element 218) can be matched to each other such that a defined (main) filter frequency is provided by the filter arrangement 200. This frequency can be specifically matched to the power system (e.g., comprising a transformer and a connected power transmission conductor). The filter arrangement 200 can have a lower impedance, particularly above the mains frequency. Harmonic currents flow through the filter arrangement 200 and are attenuated, in particular, by the resistive element 218. Harmonics can thus be filtered in a simple and reliable manner.

[0063] As can be seen, the first electrical connection comprises 206 in the Fig. 2a no switch.

[0064] The Fig. Figure 2b shows a schematic view of a further embodiment of a filter arrangement 200 according to the present invention. To avoid repetition, only the differences from the previous embodiment are explained below, and otherwise reference is made to the descriptions, for example, regarding the previous embodiment. Fig. 2a is referred to. The essential difference is, in particular, that the first electrical connection comprises (exactly) one switch 228.

[0065] The Fig. Figure 2c shows a schematic view of a further embodiment of a filter arrangement 200 according to the present invention. To avoid repetition, only the differences from the previous embodiment are explained below, and otherwise reference is made to the descriptions, for example, regarding the previous embodiment. Fig. 2a is referenced. The essential difference is, in particular, that the first electrical connection comprises (exactly) two switches 228.1 and 228.2. The capacitive component 212 can be connected to the first switch 228.1, and the first inductive component 226 can be connected to the second switch 228.2. In some applications, this filter may exhibit zero-error phenomena. One solution to this problem may be the use of two switches, as shown in the Fig. 2c shown.

[0066] The Fig. Figure 3 shows a schematic view of a further embodiment of a filter arrangement 300 according to the present invention. To avoid repetition, only the differences from the previous embodiment are explained below, and otherwise reference is made to the descriptions, for example, regarding the previous embodiment. Fig. 2a, Fig. 2b and / or 2c were referred.

[0067] The filter arrangement 300 consists in particular of a first sub-circuit 302, comprising a first inductive element 326 connected in parallel with a capacitive element 312, and a second sub-circuit 304, comprising a resistive element 318 connected in parallel with a second inductive element 316. The first sub-circuit 302 is connected in series with the second sub-circuit 304 between the first electrical terminal 306, which can be connected to the power transmission conductor 308, and the second electrical terminal 310. A three-phase filter arrangement is again shown as an example.

[0068] In the present embodiment, the first inductive element 326 and the second inductive element 316 are formed by a common coil 330 with a center tap 332. The first inductive element 326 can be formed by a first winding of the common coil 330, which extends from a first terminal 334 of the common coil 330 to the center tap 332. The second inductive element 316 can be formed by a second winding of the common coil 330, which extends from the center tap 332 to the second terminal 336 of the common coil 330.

[0069] The Fig.Figure 4 shows a schematic view of an embodiment of an electrical power system 440 according to the present invention with an embodiment of a filter arrangement 400 according to the present invention. For the sake of clarity, the details of the filter arrangement 400 have been omitted. The filter arrangement can be, in particular, designed according to the filter arrangement according to Fig. 2a, Fig. 2b, Fig. 2c and / or 3 must be formed.

[0070] In the present embodiment, the power system 440 is configured as a power generation system, in particular in the form of a wind farm. It is understood that the following explanations can also be applied to other power systems, such as other power generation systems (e.g., photovoltaic parks) or power consumption systems (e.g., hydrogen production plants). Such systems can also be combined with one another.

[0071] A power system 440 can comprise at least one power device 442. The at least one power device 442 comprises at least one power generator and / or at least one power consumer. For the purposes of this example, a plurality of power generators is provided, in particular in the form of a plurality of wind turbines.

[0072] The power system 440 can be, in particular, an offshore power system, in this example an offshore wind farm. The offshore wind farm can comprise a large number of offshore wind turbines.

[0073] The at least one electrical power device 442 can be connected (directly or indirectly) to an electrical power transmission conductor 408. In the present case, the power system 440 specifically comprises the power transmission conductor 408. The at least one power transmission conductor 408 can be a medium-voltage cable or a high-voltage cable. It is understood that in variants of the invention, two or more power transmission conductors can be provided. In particular, the medium-voltage cable or high-voltage cable can be a submarine cable. The medium-voltage cable or high-voltage cable can have a length of at least more than 10 km.

[0074] Furthermore, the power system 440 includes, by way of example, at least one first transformer 446. As can be seen from the Fig.As can be seen from Figure 4, the at least one power device 442 can be electrically connected to the power transmission conductor 408 by means of the at least one transformer 446. In particular, the power system 440 can comprise an (offshore) substation 444, designed to support the at least one first transformer 446.

[0075] As previously described, the power system 440 comprises at least one filter arrangement 400. For example, the number of filter arrangements can depend on the number of power transmission conductors that form the network connection. In particular, a filter arrangement 400 can be connected to each power transmission conductor 408.

[0076] The first electrical connection of the filter assembly is connected to the power transmission conductor 408. In variants of the invention (not shown here), the filter assembly can be arranged adjacent to the first transformer. This means, in particular, that the substation can include the transformer and the filter assembly. Due to the reduced number of components in the filter assembly, its space requirement is reduced.

[0077] The power transmission conductor 408 is connected, in particular, to an electrical distribution network 452. In this case, the power transmission conductor 408 is connected to the electrical distribution network 452 by means of a second transformer 450, which is, for example, arranged at a second (onshore) substation 448. Preferably, the filter arrangement 400 can be arranged adjacent to the second transformer 450. The electrical distribution network 452 is, in particular, a (public) extra-high-voltage network (e.g., between 110 kV and 380 kV), a (public) high-voltage network (e.g., between 50 kV and 110 kV), and / or a (public) medium-voltage network (e.g., between 1 kV and 50 kV). The power system 440 can comprise the at least one second transformer 450 and / or the second substation 448.In variants of the invention, a further (not shown) filter arrangement according to the invention can be arranged on the second substation 448 and in particular connected to the power transmission conductor 408. Reference symbol list: 100 filter arrangement 102 first sub-circuit 104 second sub-circuit 106 first connection 108 energy transmission conductors 110 second connection 112 capacitive component 114 capacitive component 116 inductive component 118 Resistance element 120°C filter 122 Reactive power compensator 124 inductive component 200 filter arrangement 202 first sub-circuit 204 second sub-circuit 206 first electrical connection 208 energy transmission conductors 210 second electrical connection 212 capacitive component 216 inductive component 218 Resistance element 226 inductive component 228 switches 300 filter arrangement 302 first sub-circuit 304 second sub-circuit 306 first electrical connection 310 second electrical connection 312 capacitive component 316 inductive component 318 Resistance element 326 inductive component 330 common coil 332 Center tap 334 first connection 336 second connection 400 filter arrangement 408 Energy transmission conductors 440 performance system 442 Power device 444 Substation 446 Transformer 448 Substation 450 transformer 452 Distribution network

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