Cable route and operation of a cable route

Abstract

Cable route for underground installation of power cables with at least one planar heat-conducting element, several power cables which are connected to the heat-conducting element at a distance from each other and thermally coupled to transfer heat from the respective power cable to the heat-conducting element, wherein the heat-conducting element and the power cables are arranged in the ground.

Description

The present invention relates to a cable line for underground installation of power cables and to a method for operating such a cable line. The present invention further relates to a cable route element for dissipating the heat loss of the cable route to the ground. In particular, the invention relates to a method for the active or passive cooling of the cable trays and for making the waste heat of the power cable cables usable for other applications such as a heat network.As the power demand of industry and society increases, it is necessary to build up and renew the existing power grid. Due to the decided omission of fossil energy carriers and the simultaneously occurring electrification of the sectors of heat and traffic, the current demand rises sharply up to the year 2055, for which purpose new cable trays for forwarding and distributing the current must be created, which are in particular designed as high-voltage trains. To avoid overland lines, new cable tracks are usually laid in the ground. In this case, the individual high-voltage cables are laid next to one another at a horizontal distance from one another which is dimensioned such that the heat dissipation of the cables to the ground is sufficient in order not to impair the service life during operation of the line with the design performance. However, this requires a considerable space requirement, so that a current route of present-day construction usually has a width of 30 m or more, in which neither construction nor planting with deep-rooting trees is permitted. In addition to the associated high costs, environmental damage and design risks for the construction in conventional construction design, the difficulty of finding and making possible such route guidance even increases with the required space requirement.Furthermore, in high-voltage roads laid close to the surface in the ground, there is the problem that waste heat from the high-voltage cables, in particular the high-voltage direct current (HVDC) cables, is only insufficiently dissipated into the ground, since the ground, in particular in the dry state, has only a low thermal conduction of approximately 0.3 W / mK. Thus, heating of the cables and the soil to up to 90° C. can occur locally. As the temperature rises, the system resistance in the high-voltage cable itself also rises, so that the electrical losses continue to rise. Present-day high-voltage roads usually have a loss rate of 0.5% per 100 km, which leads to waste heat of approximately 200 kW / km in the case of a 4 GW HGU line. These considerable amounts of heat must be dissipated. If this is not possible, either the performance of the high-voltage train has to be reduced in order to avoid exceeding the material-dependent limit temperature of, for example, cable core or cable sheath, which would lead to damage to, for example, the high-voltage cables, or expensive bedding materials with improved thermal properties have to be used for embedding the cables, which is associated with a considerable additional logistic outlay and costs. The high voltage road is thus available in the power grid only with a reduced power which is provided by the Bottleneck of the route guidance with the worst heat conduction of the underlying surface.Furthermore, in order to avoid mutual thermal influence, the individual high-voltage cables are laid at a greater horizontal distance from one another. Even if this has a positive effect on the dissipation of the heat generated, this further increases the required space requirement of such a high-voltage road, the environmental loads thereof in the construction, the masses of excavation material and the visibility as a snow in the landscape.DE 10 2007 061 802 B3 describes a channel system for receiving power cables with the following features or elements: with a trench provided in the ground; with a walkable channel cast or prefabricated in the trench made of a material based on concrete. Outside the channel, bodies for absorbing and / or dissipating thermal energy are arranged.DE 24 23 717 A1 describes a cooling system for power cables laid underground.DE 10 2020 106 331 A1 describes a thermally activated sheet pile wall profile.DE 20 2011 103 140 U1 describes an apparatus for cooling buried power cables, having a substantially tubular jacket for receiving at least one power cable; at least one first fluid connection which is connected to the jacket and has at least one fluid inlet opening for introducing a cooling fluid into the jacket; at least one second fluid connection which is connected to the jacket and is connectable or is connected to a heat utilization apparatus for utilizing the waste heat of the at least one power cable; and a fluid conveying device for conveying a cooling fluid from the at least one first fluid connection through the jacket to the at least one second fluid connection, wherein the cooling fluid is at least partially in heat exchange with the at least one power cable on its path through the jacket.EP 2 374 942 A1 describes a thermally activated sheet pile wall.It is an object of the present invention to provide a compact cable route with increased availability.The object is achieved by a cable route element for use in an underground cable route according to claim 1, a cable route for laying power cables according to claim 2, a system comprising such a cable route according to claim 16, and a method for operating a cable route according to claim 17.In one aspect of the present invention, a cable route element is provided for use in a underground cable route. The cable route element has a heat-conducting element for introducing into the ground and forwarding the heat generated in the power cables into the ground and / or to a heat exchange element. In particular, the heat-conducting element is configured planar. Here, the surface area of the property of the heat conducting element denotes to provide a large surface area in comparison to the lateral surface of an individual power cable, which is then in contact with the ground for dissipation of the heat. In particular, the heat-conducting element is substantially plate-shaped and thus has a greater width and length than thickness. The heat-conducting element can be designed as a planar plate or can have a profile, as is the case, for example, if the heat-conducting element is designed as a sheet pile wall, as described further below. This provides a large contact surface with the soil. Furthermore, the cable route element has a plurality of receiving elements connected to the heat-conducting element, each for receiving one or more power cables, wherein the receiving elements extend at least in sections and in particular continuously along the heat-conducting element and are arranged at a distance from one another. As described further below, the individual receiving elements can each receive one or more power cables, which are then connected to the heat-conducting element and in particular are thermally coupled thereto. Heat which is generated in the power cables can thus be efficiently dissipated to the ground via the receiving elements and the heat-conducting element, so that the distance between the individual power cables can be reduced. At the same time, the heat-conducting element offers mechanical protection for the power cables, so that safety distances can be reduced, in particular for planting and / or planting with deep-rooting plants.The heat-conducting element is preferably a metallic heat-conducting element and, in particular, the heat-conducting element comprises steel or aluminum or consists of steel or aluminum. Alternatively, the heat-conducting element comprises plastic or consists of plastic or is produced from plastic. In particular when using plastic, on the one hand, good thermal conductivity is provided, on the other hand, only small currents are at most induced in the heat-conducting element when used in an alternating current route on account of the low electrical conductivity of plastics.The heat-conducting element preferably has a heat conduction of more than 10 W / mK, in particular more than 30 W / mK and preferably more than 50 W / mK.According to the invention, the heat-conducting element is formed from one or more sheet pile wall profiles. In particular, the sheet pile wall profiles form a sheet pile wall as a heat-conducting element, by means of which, on the one hand, mechanical protection of the power cables and the cable route is ensured and, on the other hand, heat can be emitted to the soil over a large area via the surface of the sheet pile wall. The sheet pile wall has a plurality of sheet pile wall profiles connected to one another, which are anchored in the ground and are connected in a force-fitting manner to the adjacent sheet pile wall profiles via the sheet pile wall locks. In this case, the sheet pile wall profiles are arranged continuously next to one another in a known manner, so that, apart from the first and last sheet pile wall profile, each sheet pile wall profile is connected to exactly two adjacent sheet pile wall profiles. In addition, anchor elements and reinforcements can be provided, which become statically required and serve for load transfer into the adjacent construction ground. Alternatively or additionally, braces and braces can be used for mutually supporting the steel sheet pile walls in the case of trench construction. The individual sheet pile wall profiles are thereby introduced into the soil according to recognized rules of construction technology, for which purpose all recognized introduction methods, such as pressing, beating or vibrating, can be used. Known sheet pile wall profiles have profile lengths of up to more than 30 m. The sheet pile wall profiles consist of steel or aluminum, which has a high heat conduction of about 52 W / mK. The sheet pile wall profiles or the sheet pile wall formed therefrom extend in the direction of extension of the cable route.Preferably, the sheet pile wall has one or more receiving elements arranged at a vertical distance, wherein the receiving elements are designed to receive at least one individual or more power cables. The vertical arrangement relates to the installed state, so that when a power cable is received by the receiving elements, the power cables are arranged one above the other along the longitudinal axis of the sheet pile wall, consisting of the individual sheet pile wall profiles, in the direction of extension of the cable route. In other words, the receiving elements are arranged distributed in the vertical direction to the longitudinal axis of the sheet pile wall. In this case, the respective receiving elements are arranged at least in sections and in particular continuously one above the other on the sheet pile wall profiles in the direction of extension of the cable route. Thus, a plurality of power cables can be fastened to the sheet pile wall by a corresponding number of receiving elements and be connected in a thermally conductive manner, wherein the power cables are then no longer arranged horizontally next to one another, as is the case with current laying methods in cable trays. Rather, the power cables are arranged one above the other, so that the trench width of the cable route formed with the sheet pile wall and / or the excavation masses can be significantly reduced and at the same time the transmission power of the cable routes can be significantly increased. At the same time, the waste heat which arises and is generated by the power cables can be dissipated efficiently into the soil by the respective sheet pile profiles. In this case, the sheet pile wall profiles create a clearly enlarged contact surface with the soil. Owing to the good thermal conductivity of the sheet pile wall profiles, these serve as a heat-conducting element, so that the heat generated by the power cables can be dissipated uniformly via the sheet pile wall profiles of the sheet pile wall and can then be dissipated to the construction ground over a large area and thus efficiently. As a result, the contact surface between an electric cable and the ground increases significantly and in particular by a factor of 10 or more.The cable route element is preferably further developed on the basis of the features of the cable route as described below. In particular, the cable route element may comprise one or more heat exchange elements, as described below. Alternatively or additionally, the cable route element can have receiving elements, as explained in more detail below and in particular in connection with the figures.In another aspect of the present invention, a cable route for underground installation of power cables is provided. The cable route has at least one heat-conducting element, in particular a planar heat-conducting element, wherein a plurality of power cables are connected to the heat-conducting element at a distance from one another and are thermally coupled to the heat-conducting element for dissipating heat from the respective power cables. In this case, the heat-conducting element and the power cables are arranged in the ground and at least the heat-conducting element is at least partially in direct contact with the ground. Heat generated by the power cables is transmitted to the heat conducting element and can thereby be dissipated to the ground via a large contact surface. The waste heat generated from the power cable can thus be dissipated more efficiently, so that the power cables can be located closer to one another without the risk that excessive heating of the soil and / or of the power cables requires a throttling of the transmission power of the cable route. At the same time, the width of the cable trays can be reduced and efficient and reliable heat dissipation of the waste heat from the power cables can be ensured. According to the invention, the cable route has one or more cable route elements, as described above. According to the invention, the heat-conducting element is thus formed by a sheet pile as described above, wherein the power cables are arranged in the receiving elements of the sheet pile. By providing the sheet pile wall, a mechanical protection of the power cables is also provided, so that safety distances for the construction and / or planting can be reduced, whereby the required route width can be further reduced.The cable route is preferably designed as a high-voltage DC power transmission line. Alternatively, the cable route is designed as an AC transmission line. In this case, the heat-conducting elements are manufactured in particular from a plastic in order to prevent induction of a current in the heat-conducting element.The cable route is preferably designed to transmit 1000 GW or more, preferably 4000 GW or more and preferably 8 GW or more, which corresponds to more than twice the value of the southwest link (4 GW) currently in construction planning.Preferably, the power cables are operated at 525 kV or more, preferably 600 kV or more.Preferably, the heat conducting element is arranged horizontally and the arrangement of the power cables is provided at a horizontal distance from one another. By horizontally arranging the power cables, the conventional design in the form of an open trench design is further possible. However, by providing the heat conducting member, heat dissipation is improved by the improved thermal conductivity of the heat conducting member and the area, which is in contact with the ground to release the heat, enlarged by the heat conducting member.Alternatively, the at least one heat conducting element is arranged vertically. As a result, the width of the required cable route can be significantly reduced, since the individual power cables can be arranged at a vertical distance from one another or one above the other.Preferably, all power cables are arranged on one side of the heat conducting element. Alternatively, the power cables may be arranged on both sides of the at least one heat conducting element, whereby the number of possible power cables may be increased without reaching too great a depth.The heat-conducting element is preferably a metallic heat-conducting element and, in particular, the heat-conducting element comprises steel or aluminum or consists of steel or aluminum. Alternatively, the heat-conducting element comprises plastic or consists of plastic or is produced from plastic. In particular when using plastic, on the one hand good thermal conductivity is provided, and on the other hand no currents are induced in the heat-conducting element when used in an alternating current route.The heat-conducting element preferably has a heat conduction of more than 10 W / mK, in particular more than 30 W / mK and preferably more than 50 W / mK.Preferably, the heat-conducting element extends in sections along the cable route and, in particular, the heat-conducting element extends continuously along the cable route.Preferably, the vertical distance between the power cables is constant. Alternatively, the distance of the power cables in the vertical direction varies according to the possibility of the soil to dissipate the generated heat of the respective power cables. For example, power cables arranged further above can be arranged further apart than power cables arranged further below, since heat dissipation into the underlying soil can take place more efficiently. In particular, the heat-conducting element, if it is designed as a sheet pile, can have a larger surface than is required for the arrangement of the receiving elements and assembly of the power cables, since statically for load removal of the sheet pile profiles into the soil, they engage deeper into the soil, so that the respective sheet pile profiles have an even larger surface in contact with the deeper soil.Preferably, heat conducting elements are arranged vertically at a horizontal distance from each other, wherein a plurality of power cables are connected to each heat conducting element. Thus, a sufficient number of power cables with respective thermal conductive elements may be provided to provide an efficient cable route.Preferably, the heat-conducting elements are designed as sheet pile wall profiles and in particular as sheet pile wall as described above, which are then arranged opposite one another in particular as trench construction from sheet pile wall profiles. In this case, in particular the receiving elements of the respective sheet pile walls point towards one another. Furthermore, the sheet pile walls can be supported mechanically against one another in order to increase the static load pick-ups and / or to reduce the binding depths and the resistance values of the individual sheet pile wall profiles.Preferably, an earthless and in particular walkable channel is formed between the two heat-conducting elements, in which channel the power cables are arranged, wherein the heat-conducting elements adjoin the ground on the side opposite the channel. In particular, all power cables are arranged within the channel. Thus, the trench construction from sheet pile walls forms a service channel in which the receiving elements and the power cables can be mounted on the sheet pile wall. In particular, this channel is sufficiently large to be walkable on, optionally travelable, which considerably simplifies the installation of the power cables, their maintenance or replacement.Preferably, the horizontal distance between the two heating elements is between 1m and 10m and preferably between 2m and 3m. By means of the two heat-conducting elements, in particular if they are provided as sheet-metal partitions, technical protection of the power cables is likewise provided, so that the lateral safety distance for construction and / or planting can be further reduced.Preferably, the height of the channel is 2m-8m and preferably between 3m-5m.The cable route preferably has at least 2 power cables, in particular more than 4 and preferably more than 8 power cables. In particular when more than one heat conducting element is provided, 2 or more, preferably 3 or more and particularly preferably 4 or more power cables are connected to each heat conducting element.Preferably, the vertical distance between two adjacent power cables is more than 50 cm, in particular more than 75 cm and preferably more than 100 cm. This creates a sufficient distance, so that a mutual thermal influence on the individual power cables is at least reduced.The cable route preferably has a width of less than 10 m, in particular less than 5 m and preferably less than 3 m. This creates a space-saving cable route which can be efficiently cooled and thus reliably operated.Preferably, the channel comprises a cover. In particular, this cover is designed as a roadway surface which is supported on the upper edges of the respective heat-conducting elements, which is preferably designed as a sheet pile wall profile or sheet pile wall that can be subjected to high static load. Thus, on the one hand, a walkable cable duct is provided in a simple manner and, on the other hand, the possibility of the cable line being able to be traveled through during the construction phase of the cable line is ensured in a simple manner and, after completion, for use as a travel path. It is thus possible to lay a cable route below a road, for example, as a result of which a double use of the cable route is made possible and the need for further space for a separate cable route or a separate road is dispensed with.Preferably, the channel is ventilated and in particular forcibly ventilated. By convective cooling of the power cables which are arranged within the channel, a further heat dissipation can be provided in addition to the heat conduction via the heat-conducting elements. The heat dissipation of the heat generated by the power cables can be improved thereby.Preferably, the respective power cables are arranged in the receiving elements, wherein each power cable is surrounded in particular from three sides by the receiving element and / or the heat-conducting element. Thus, the receiving elements and the heat conducting element create U-shaped brackets into which the power cables can be inserted. The receiving elements are connected indirectly or directly to the heat-conducting elements, so that a heat transfer from the receiving elements to the heat-conducting element is also made possible. Since the respective power cables are surrounded by the receiving element and / or the heat-conducting element from three sides, heat can be effectively dissipated to the heat-conducting element and then into the ground.The receiving elements preferably comprise steel or consist of steel or are produced from steel. Alternatively, the receiving element can also be made of plastic.Preferably, the receiving elements are non-detachably connected to the respective heat conducting element in a materially integral manner, for example by means of welding.Preferably, a thermal coupling takes place between the respective power cable and the receiving element or the heat-conducting element. In this case, for example, a heat conducting means such as graphite or another heat conducting casting compound can be introduced into the receiving elements, so that the respective power cables are substantially completely, but at least partially, surrounded by this heat conducting means and there is full-area contact with the receiving element or the heat conducting element. Alternatively, the heat conducting means can also be provided only between the respective power cable and the side of the heat conducting element, so that the power cable essentially rests on the receiving element and is directly coupled to the side of the heat conducting element. If a heat exchange element is provided, as described in detail below, a thermal coupling can take place directly with the heat exchange element.Preferably, the power cables do not have a cable protection tube. Power cable for high voltage transmission according to the invention. The prior art is usually laid in a plastic pipe in order on the one hand to avoid damage to the power cable and on the other hand to ensure the exchangeability of the cables in the ground in the event of repair. Such a cable protection pipe presents thermal resistance due to the air layer between the power cable and the cable protection pipe and further reduces the heat dissipation of the power cables to the ground. However, such cable protection pipes are not required in the cable line of the present invention, so that a cable protection pipe can be omitted. As a result, a direct thermal coupling of the power cable to the heat-conducting element is possible.The cable route preferably has an irrigation device which makes it possible to specifically wet the soil next to the heat-conducting elements or next to the sheet pile wall profiles. The irrigation can raise the thermal conductivity of the soil from, for example, 0.3 W / mK at low moisture content to, for example, 2 W / mK at high moisture content. Thus, the dissipation of heat into the soil can be improved via the irrigation, whereby it becomes possible, for example, to operate the electricity route with higher power when a large amount of electricity is required.Preferably, adjacent power cables have an opposite polarity. As a result, the magnetic fields generated by the current flow are compensated for, so that the magnetic field generated by the cable line is minimal at the surface.The cable route preferably has a shielding device for minimizing the electromagnetic flux density at the surface of the earth. In this case, the shielding device can be designed as a metal plate which covers, in particular, the floating channel. Thus, a Faraday cage closed on three sides is created by the shielding device and the two heat-conducting elements, so that the electromagnetic field strength at the surface of the earth is minimal in order to maintain possible electromagnetic compatibility with other electrical devices such as electric cars.The cable route preferably has one or more heat exchange elements for absorbing the heat of the power cables and forwarding them by means of a heat transfer medium. For this purpose, the heat exchange element is in at least indirect contact with one or more power cables. In particular, the heat exchange element is in direct contact with one or more power cables. Preferably, a heat exchange element is in contact with all the power cables, which is connected to one of the heat conducting elements. Thus, in particular exactly one heat exchange element per heat conducting element is provided. Alternatively, exactly one heat exchange element can be provided for each power cable. Heat can be actively dissipated by the heat exchange element, thereby further increasing the efficiency of heat dissipation caused by the power cables. Thus, on the one hand, heat of the power cables is efficiently dissipated to the ground by the heat-conducting element. Preferably, the heat can be utilized by the heat exchange element. As stated above, when power is transferred for the example 4G cable line, about 200 kW / km of heat output is generated, which can be absorbed and utilized by the heat exchange element.The heat-conducting elements are preferably equipped with collectors in which a circulating heat transfer medium is used, so that the cables can also be actively cooled besides passively. The waste heat recovered in this case from the cable route can optionally be used via heat networks for heating purposes for building heating by means of heat pumps.For this purpose, the heat-conducting element is preferably designed as a thermally activated sheet pile wall. This is described, for example, in EP 2 374 942 A1 "Device and method for heat recovery from the environment" and DE 10 2020 106 331.8 "Thermally active sheet pile lock profile".The heat-conducting elements preferably consist of thermally activated steel sheet walls, the collectors of which are coupled to circulation or heat pumps and in which a heat transfer medium circulates.The heat exchange element is preferably a heat exchanger in which a heat transfer medium is used, which flows through the heat exchange element and in this case absorbs and transfers heat from the respective power cables. The heat transfer medium can be, for example, water, another liquid or a gas. Alternatively, the heat exchange element is a heat pipe, wherein CO 2 is used as the heat transfer medium, for example, which absorbs heat in its evaporation region and gives off heat in the condensation region to a further or different heat transfer medium. In particular, the heat exchange elements can be combined in this case, so that, for example, heat pipes are provided which are in contact with the respective power cables, wherein the heat pipes emit their heat to a heat exchanger with water as heat carrier medium for transmission.Preferably, the heat exchange element is arranged between the power cables and the heat conducting element. This ensures that as much heat as possible can be absorbed by the heat exchange element and made usable. Only the heat that is not absorbed by the heat exchange element can be emitted to the ground via the heat conducting element, as described above. Efficient heat dissipation is thus also ensured if no heat is removed by the heat exchange element, for example on account of a lack of heat requirement. Alternatively, the heat exchange element is arranged on the side of the heat conducting element opposite the power cables.The heat exchange element is preferably designed as a cover which at least partially surrounds one or more power cables and in particular all power cables which are arranged in a receiving element, such that a heat transfer medium can flow between the cover and the respective power cable. The cover thus creates a channel, in particular in combination with the receiving element, within which channel the power cable is laid and a heat transfer medium can simultaneously flow along the power cable. The heat transfer medium can be, for example, water or air. Other liquids or gases are also possible. The heat of the power cables is thus absorbed by the flowing heat transfer medium and can be conducted on and used for various applications.Preferably, the heat exchange element is arranged at least partially along the power cables in the respective receiving element. Thus, one heat exchange element can be provided for each receiving element. In particular, the heat exchange element is designed as a hollow body, for example in the form of a tube, which carries a heat transfer medium. The heat transfer medium thus flows parallel to the power cables, but is separated from these by the wall of the hollow body, so that the power cables do not come into contact with the heat transfer medium. In order to achieve a good thermal coupling between the respective power cables and the heat transfer medium, the tube of the hollow bodies can be plastically deformable and thereby bear directly on one or more power cables in a form-fitting manner. In particular, the plastically deformable hollow body bears directly against all the power cables of a receiving element. Alternatively or additionally, a heat conducting means can be provided between the hollow body and the respective power cables, so that the heat conducting means is thermally coupled to one another with one or more power cables. In this case, the hollow body can also be round in cross section. In particular, the above heat exchange elements can be combined with the heat exchange elements which are connected to the heat conducting element.Preferably, a connecting line is provided along the cable route for forwarding a heat transfer medium to a consumer and / or a heat store. This can be effected, for example, via a heat network, which is preferably designed as a low-temperature heat network. In particular, the connecting line is provided in the floating channel and is thus simple and, in contrast to the prior art, cost-effectively deployable, easily accessible and, in addition, does not have to be insulated either because of the elevated temperatures in the floating channel. In this case, the connecting line is connected to a consumer, such as, for example, a home person or the industry, which can use the generated heat of the cable route. Alternatively or additionally, the connecting line is connected to a heat store, which can be designed, for example, as a seasonal heat store. Heat that is not required can thus be temporarily stored in the heat store until there is a need that exceeds the heat generated by the cable route. In this case, heat can be made available and used from the heat store. The heat store is, for example, a heat storage medium such as, for example, water, zeolite, rock or the like. Due to the availability and high heat capacity of these materials, a large amount of heat may be stored and provided to the respective consumers as needed. Thus, for example, in summer the heat of the cable route can be stored in the seasonal heat store, since little heat is required by consumers. In winter, there is an increased heat requirement for heating purposes, which can then be covered by the seasonal heat store.In a further aspect of the present invention, a system is provided having a cable route as described above and a heat network and / or heat store connected to the cable route.In a further aspect of the present invention, a method for operating a cable route is provided, wherein the cable route has in particular a heat exchange element as described above, such that the heat generated in the power cables can be dissipated by means of the heat transfer medium.Preferably, when the heat requirement is lower than the generated heat of the power cables, the heat is stored in a heat storage.Preferably, when the heat requirement is greater than the generated heat of the power cables, heat is removed from the storage. Thus, sufficient heat is always available for respective consumers and a fully annual use of the heat generated by the power cables is made possible.The invention is explained in more detail below on the basis of preferred embodiments with reference to the appended figures.The following are shown: FIG. 1A shows a sheet pile wall as cable route element according to the present invention in plan view, FIG. 1B shows the sheet pile wall of FIG. 1A in a side view, FIG. 1C shows the sheet pile wall of FIG. 1A in a sectional view, FIG. 2 shows a cable route in a first embodiment, FIGS. 3A to 3C are detailed views of the cable line according to the present invention, FIGS. 4A-4F are detailed views of a cable line according to the present invention, FIG. 5 shows a further embodiment of a cable route according to the present invention, and FIG. 6 is a schematic diagram of the operation of a system having a cable route and a heat network according to the present invention.FIG. 1A shows a sheet pile 10 which has a plurality of sheet pile profiles 12 connected to one another, which sheet pile profiles can extend in a direction 11 of extension of the cable route. In this case, the respective sheet pile wall profiles 12 are connected directly to their adjacent sheet pile wall profiles via the sheet pile wall locks, so that a closed sheet pile wall 10 is produced. Here, one or more receiving elements 14 are connected to the individual sheet pile wall profiles 12 and extend at least in sections and in particular continuously along the extension direction 11 of the sheet pile wall 10, in particular along the longitudinal axis of the cable duct secured to the sheet pile wall 10. The receiving members 14 are described in detail with reference to Figs. 3A-3C and 4A-4D. The receiving elements 14 are configured to receive one or more power cables 18 each, which extend and are held in the respective recesses 16 of the receiving elements 14, configured as a console. The receiving elements 14 are directly connected to the sheet pile wall profiles 12.As shown in the embodiment of FIG. 1C, four receiving elements 14 are connected to the respective and in particular all of the sheet pile wall profiles 12 of the sheet pile wall 10, which receiving elements can then carry four or more power cables 18. In this case, the present invention is of course not limited to the number of the illustrated receiving elements 14 and power cables 18, and therefore further or few receiving elements 14 and power cables 18 can be provided accordingly.Reference is now made to Figure 2 which illustrates a cable line according to the present invention. Here, a heat conducting element 17 is arranged vertically. The power cables 18 are directly connected via the receiving elements 14 to the heat-conducting element 17, which is designed as a sheet-metal profile 12 according to FIGS. 1A to 1C. The heat conducting element 17 is arranged together with the receiving elements 14 and the power cables 18 in the ground 22 below the surface 13. The heat-conducting element 17 is in particular made of steel and thus intrinsically has good thermal conductivity in comparison to the thermal conductivity of the ground 22, The heat-conducting element 17 enables more uniform dissipation of heat of the heat generated by the power cables 18 into the ground 22 as a result of the increased contact surface. The heat dissipation from the power cables 18 into the ground is higher and in particular more uniform, whereby temperature peaks in the power cables 18 and in the ground are avoided and an operation of the cable route with constantly high or even higher power is made possible.Even if the vertical distance of the individual receiving elements 14 and the power cables 18 is shown constant in FIG. 2, this can be deviated from, so that a changing vertical distance between two successive power cables 18 is also encompassed by the present invention. Furthermore, FIG. 2 shows that all receiving elements 14 are of identical design. This can also be deviated from, so that different receiving elements 14 are also encompassed by the present invention.Reference is now made to FIGS. 3A to 3C. In FIG. 3A, the receiving element 14 is directly connected to the heat-conducting element 17. For improved thermal coupling of the power cable 18 to the heat-conducting element 17, a heat-conducting means 20 can be introduced into the recess 16, formed by the receiving element 14, which is provided, for example, as a casting compound or bulk material. In particular, the heat conducting means 20 is graphite or comprises graphite. Thus, good heat conduction is ensured over the entire circumference of the power cable 18 to the heat conducting element 17, as a result of which the amount of heat dissipated from the power cable 18 is maximized. As a result, either the cable temperature and thus the losses can be lowered and / or the performance of the line can be increased.In another embodiment, shown in FIG. 3B, a heat exchange element 24 is disposed between the power cable 18 and the heat conducting element 17. A heat transfer medium can flow through the heat exchange element 24, for example. The heat transfer medium absorbs the waste heat that arises from the power cable 18 and transports this heat via lines 34 to a consumer or a heat store. In particular, the heat transfer medium is air, water, another liquid or, if the heat exchange element 24 is designed as a heat pipe, for example CO 2. The heat generated by the power cable 18 can thus be utilized.According to the invention, the heat conducting element 17 is a thermally activated sheet pile wall as described, for example, in EP 2374942 "Device and method for heat generation from the environment" or DE 10 2020 106 331.8 "Thermally active sheet pile wall lock profile". In this case, the heat is, on the one hand, efficiently dissipated from the power cable 18 by the heat exchange element 24 and, on the other hand, this heat is made usable for a consumer.In another embodiment shown in FIG. 3C, the power cable 18 and the heat exchange element 24 are arranged on opposite sides of the heat conducting element 17.Reference is now made to FIGS. 4A-4D. The embodiment of FIGS. 4A-4D can be freely combined with the embodiments of FIGS. 3A to 3C. For this purpose, a contact surface 26 is indicated in particular, wherein the contact surface 26 can bear directly against a heat exchange element 24 according to the embodiment of FIG. 3B or can bear directly against a heat conducting element 17 according to the embodiments of FIGS. 3A and 3C.The embodiment of FIG. 4A corresponds to the embodiments of FIGS. 3A to 3C, wherein a heat conducting means 20 is arranged in the recess 16 formed by the receiving element 14 and surrounds the power cable 18 for improving the thermal conductivity in the direction of the heat exchange element 24 or the heat conducting element 17, respectively. The receiving element 14 of FIG. 4A is Z-shaped and surrounds the power cable 18 only on two sides, wherein the power cable 18 directly adjoins the heat exchange element 24 or the heat conducting element 17 on its third side. In an alternative embodiment shown in FIG. 4B, the receiving element 14' is U-shaped, so that the receiving element 14' surrounds the power cable 18 on three sides. In both embodiments of Figures 4A and 4B, the receiving element 14, 14' is in direct contact with either the heat exchange element 24 or the heat conducting element 17. in particular, the receiving element 14, 14' is made of steel which has good thermal conductivity and thus optimizes the amount of heat transferred from the power cable 18 in the direction of the heat exchange element 24 or the heat conducting element 17.In FIG. 4C, a potting compound 20' is introduced only in the region of the direct contact surface between the power cable 18 and the boundary surface 26 with the heat exchange element 24 or heat conducting element 17, which enables single-sided heat conduction. The receiving element 14 here serves substantially for mechanically holding the power cables 18, but it goes without saying that, owing to the direct contact on the support frames, it also supports the heat conduction.In FIG. 4D, the receiving element 14 is covered by a cover 30, which creates a cavity 28 in which the power cable 18 is arranged. A heat transfer medium flows through the cavity 28, which absorbs heat from the power cable 18 and transfers it for further use. The heat exchange element is thus formed by the cover 30 and cooperates with the receptacle 14. In particular, the heat exchange element can be combined by the cover 30 with the heat exchange element 24, which is arranged in particular on the heat conducting element 17. The heat transfer medium which flows through the cavity 28 can be, for example, water, another liquid, air or a gas which preferably has a high specific heat. The cover 30 can be designed as a plastic cover or as a metal cover. In particular, a plastic cover is cost-effective to produce, whereas a metal cover ensures better protection of the power cable against damage.Reference is now made to the embodiments of FIGS. 4E and 4F. In this case, a heat exchange element 24' is provided, which extends along the power cable 18 and is likewise arranged in the recess 16 of the receiving element 14. As shown in FIG. 4E, exactly one heat exchange element 24' can be arranged in a receiving element 14. Alternatively, a plurality of such heat exchange elements 24' are provided in a respective receiving element 14. The heat exchange element is tubular in this case, so that a heat transfer medium can flow through the heat exchange element 24' along the respective power cables 18 without the heat transfer medium coming into contact with the power cables 18. Here, the heat exchange member 24' may have a round cross section as shown in Fig. 4E. In this case, a thermal coupling between the power cables of the respective receiving element and the heat exchange element can be achieved by providing a heat conducting means 20 which surrounds both the power cables 18 and the heat exchange element 24' in order thus to ensure an efficient heat transfer from the power cables 18 to the heat transfer medium which flows in the heat exchange element 24'. Alternatively, the heat exchange element can be plastically deformable, as shown in FIG. 4F, so that the heat exchange element 24' at least partially positively abuts one, several and preferably all of the power cables 18 in the respective receiving element, so that an efficient heat transfer is ensured by the direct contact between the heat exchange element 24' and the power cables 18. Of course, a heat conducting means can also be provided in the embodiment of FIG. 4F for improving the heat conduction, which heat conducting means surrounds the power cables 18 and the heat exchange element 24' at least partially.Furthermore, the heat exchange elements 24' of FIGS. 4D to 4F can of course be combined with the heat exchange element 24, which is connected to the heat-conducting element 17 according to FIGS. 3B and 3C. Reference is made below to the embodiment of FIG. 5. In the embodiment of FIG. 5, the cable route has a first heat-conducting element 17 and a second heat-conducting element 17' spaced apart therefrom at a distance B in the horizontal direction. Four receiving elements are connected to each heat conducting element 17, 17' which in turn receive a corresponding number of power cables 18. The receiving elements 14 and accordingly the power cables 18 are arranged at a constant vertical distance di. As already explained above, this can be deviated from, so that different distances di between the individual power cables 18 can be selected. In this case, in particular, power cables 18 can be spaced further apart closer to the earth surface 13 than the lower-lying power cables, which can more effectively emit heat to the earth owing to the portion of the heat-conducting elements 17, 17' extending into the earth 22. In addition, a higher heat input in deeper layers has a less dramatic effect on the heating of the surface 13 of the earth, which should possibly not change or only change very little. In particular, the heat-conducting elements 17, 17' are designed as sheet pile wall profiles 12 which are joined together to form a sheet pile wall 10. The sheet pile wall profiles are introduced into the soil up to a depth T 2. T2 corresponds in particular to the vertical length of the individual heat-conducting elements 17, 17' and in particular to the length of the sheet pile wall profiles 12 and is, for example, 3-6 m and in particular 3-10 m. The power cables 18 are distributed over a depth T 1. Depth T1may be between 2-3 m and preferably up to 4 m. Between the two heat conducting elements 17, 17' an earth-free channel 32 is formed. In this floating channel 32, the power cables 18 laid in the receiving elements 14 are arranged in a freely accessible manner. Convective cooling of the power cables 18 can be achieved by venting the duct 32. This can be, in particular, forced ventilation.Preferably, the width B, i.e. the distance between the two heat conducting elements 17, 17' is between 2-4 m. Thus, the width of the cable route according to the present invention is also only 2-4 m, so that a considerable reduction in the space requirement of the cable route and a considerable reduction in the underground construction work can be achieved, and at the same time the heat dissipation of the power cables to the ground is clearly increased compared to the prior art.The channel 32 can be covered by a roadway 40 and / or can be used during the construction phase as a stable construction line for the creation of the cable route or, after completion of the route, as a permanent, preferably agricultural and domestically used traffic route.Heat exchange elements 24 are arranged between the receiving elements 14 and the heat conducting elements 17, 17', as described above. These heat exchange elements 24 are connected to consumers or thermal accumulators via connecting lines 34, which can be designed, for example, as a heat (remote) network. The connecting lines 34 are likewise arranged in the channel 32 and are thus easily accessible.Furthermore, sensors 35 are provided which detect the temperature in the ground 22, in the earth-free channel 32 and / or in the cables 18.Furthermore, the cable route has an irrigation device 36, by means of which the soil 22 can be watered directly next to the heat-conducting elements 17, 17'. The moisture of the soil 22 can be detected via a moisture sensor 38 and thus irrigation can be controlled as a function of the detected moisture. Moist soil (with λ to 2 W / mK) conducts heat much better than dry soil (with λ≈0.3 W / mK). If the thermal conductivity of the surrounding soil 22 is thus no longer sufficient to dissipate the heat generated by the power cables 18, in particular due to the permanently occurring water evaporation, the moisture of the soil can be increased via the irrigation device 36, as a result of which improved heat dissipation can be achieved. In this way, apart from maximizing the rated power of the line, a chronologically limited power increase can additionally be realized in order to be able to better cover peak loads, wherein the time window of the power increase is significantly larger compared to the prior art significant.Reference is made below to FIG. 6 as an example of a thermally activated sheet pile wall 10 which has a heat exchange element 24. Here, the power line is shown with a sheet pile 10 as a heat conducting element 17, a heat exchange element 24 and the power cable 18, shown as a high voltage direct current (HVDC) cable. In the heat exchanger 42 with corresponding connecting lines 44 (which may correspond to the connecting lines 34 of FIG. 5 ), the heat which is generated by the power cables 18 and is absorbed by the heat transfer medium in the heat exchange element 24 is fed into a heat network 46 and is thus made available to consumers. For this purpose, a heat exchanger 42 can be provided, as shown in FIG. 6. Alternatively, the heat exchange element 24 is directly connected to the heat network 46 and / or the heat accumulator 48 via the connecting lines 44, so that no heat exchanger is provided. If there is no or only a small amount of heat, the heat generated by the power cables 18 can be stored in a heat store 48 and then, if necessary, fed into the heat grid according to the dashed line 50. Heat exchanger 42 and heat accumulator 48 can be controlled via a control unit 52, wherein a current demand prediction 54 and a heat demand prediction 56 are incorporated into the control of heat exchanger 42 and heat accumulator 48. Here, the power demand forecast 54 refers to the amount of power to be transported through the power cables 18. If the heat generated by the power cables 18 exceeds the demand by the consumers in the heat network 46, heat can be stored in the heat store 48. On the other hand, when the demand for heat by the loads in the heat net 46 exceeds the heat generated by the power cables, heat stored in the heat storage 48 may be supplied to the loads via the heat net 46. In summer, when only heat for hot water is usually required in households, the control unit 52 ensures that in sections of the cable route with heat exchange elements 24 in which usable heat arises, the heat transfer medium is conveyed back from the heat accumulator 48 by means of a corresponding pump into the (seasonal) heat accumulator 48 and at the same time cold heat transfer medium, provided that the temperature in the heat accumulator 48 and in the lines 34 ensures a sufficient temperature spread. This process continues until the heat accumulator 48 is full. In winter, a new control command can signal the control unit 52 to feed heat from the storage 48 into the heat network 46, provided that the heat requirement prediction and the temperature sensor in the heat storage 48 acknowledge this process.For example, the power demand forecast 54 and the heat demand forecast 56 can signal a 15% higher power demand for operating heat pumps and a 40% higher heat demand due to an expected temperature fall in South Germany in the next 48 h. The control unit then sends a signal to the irrigation device to wet the soil. After the temperature drop has occurred, the current intensity and the train power can be increased by means of the control signal at the feed point of the current train, since in the meantime the capacity of the floor for absorbing additional heat was created. In the sections with heat exchange elements 24, an increased amount of heat can be fed simultaneously via the lines 34 into the heat network 46.Furthermore, FIG. 6 shows an irrigation device 36, which is connected to a water reservoir 58 via a connecting line 64. A moisture sensor 38, which is connected in particular to the control unit 52, detects the moisture of the soil in the immediate vicinity of the cable route, wherein the control unit 52 controls the moisture in the soil as a function of the detected sensor signal, as described above. Thus, in particular in the case of a forecast for an increased current demand, the current demand forecast 54 can wet the soil by means of the moistening device 36, so that optimum heat dissipation into the soil is possible at high load.Thus, on the one hand, the space requirement of a cable route is significantly reduced by the improvement of the thermal conductivity by means of the heat-conducting elements, which can be composed in particular of cost-effective and available sheet pile wall profiles. Overheating of the cable line and a necessary reduction in the power of the cable line connected therewith can thereby be avoided in particular. At the same time, the present invention can make use of the heat generated by the cable route.List of reference numbers:10 Sheet pile wall 11 direction of extension 12 sheet pile wall profile 13 surface 14 receiving element 15 arrow in FIG. 1B 16 RECESS 17, 17' HEAT CONDUCTING ELEMENT 18 POWER CABLE 20, 20' HEAT CONDUCTING MEDIUM 22 GROUND 24, 24' HEAT EXCHANGE ELEMENT 26 CONTACT SURFACE 28 CAVITY 30 COVER 32 CHANNEL 34 CONNECTING LINE 35 TEMPERATURE SENSOR 36 IRRIGATION DEVICE 38 MOISTURE SENSOR 40 ROADWAY 42 HEAT EXCHANGER 44 CONNECTING LINES 46 HEAT NETWORK 48 HEAT ACCUMULATOR 50 LINE 52 CONTROL UNIT 54 CURRENT DEMAND PREDICTION 56 HEAT DEMAND PREDICTION 58 WATER RESERVOIR 64 CONNECTING LINE

Claims

Cable route element for use in an underground cable route, having a heat-conducting element for introducing into the ground and forwarding the heat generated in the power cables into the ground and / or to a heat exchange element, having a plurality of receiving elements connected to the heat-conducting element, in each case for receiving one or more power cables, wherein the receiving elements extend at least in sections and in particular continuously along the heat-conducting element and are arranged at a distance from one another, characterized in that the heat-conducting element is formed by a plurality of interconnected sheet pile wall profiles which can be anchored in the ground.Cable route for underground installation of power cables, comprising one or more cable route elements according to claim 1 in direct contact with the ground and a plurality of power cables, wherein the power cables are arranged in the receiving elements and are thermally coupled to the heat conducting element for dissipating heat of the respective power cables, wherein the heat conducting element and the power cables are arranged in the ground.Cable route according to Claim 2, characterized in that the heat-conducting element is arranged horizontally and the power cables are arranged at a horizontal distance from one another.Cable route according to Claim 2, characterized in that the at least one heat-conducting element is arranged vertically.Cable route according to Claim 4, characterized in that two heat-conducting elements are arranged vertically at a horizontal distance from one another, wherein a plurality of receiving elements with power cables are connected to each heat-conducting element.Cable route according to Claim 5, characterized in that an earth-free channel is formed between the two heat-conducting elements, in which channel the power cables are arranged, the heat-conducting elements adjoining the ground on their side opposite the channel.Cable route according to one of Claims 2 to 6, characterized in that the respective power cables are arranged in receiving elements, wherein each power cable is surrounded in particular by the receiving element and / or the heat-conducting element on three sides.Cable route according to one of Claims 2 to 7, characterized byan irrigation device which is arranged in the soil next to the cable route for irrigation in order to improve the thermal conductivity of the soil.Cable route according to one of Claims 2 to 8, characterized in that the power cables are DC cables and the cable route is a DC transmission line, or in that the power cables are AC cables and the cable route is an AC transmission line.Cable route according to one of Claims 2 to 9, characterized byone or more heat exchange elements for absorbing the heat produced in the power cables and forwarding it by means of a heat transfer medium, wherein the heat exchange element is in each case connected to one or more power cables.Cable route according to Claim 10, characterized in that the heat exchange element is arranged between one of the power cables and the heat-conducting element, or the heat exchange element is arranged on the side of the heat-conducting element opposite the power cable.Cable route according to Claim 10 or 11, characterized in that the heat exchange element is designed as a cover which surrounds one or more power cables in each case at least partially, with the result that a heat transfer medium can flow between the cover and the one or more power cables.Cable route according to claim 10 or 12, characterised in that the heat exchange element is arranged at least in sections in the respective receiving element along the power cables.Cable route according to claim 13, characterised in that the heat exchange element is designed as a hollow body which conducts a heat transfer medium, wherein the hollow body bears in a form-fitting manner against one or more power cables or is plastically deformable and / or is thermally coupled to one or more power cables by means of a heat-conducting means.Cable route according to one of Claims 10 to 14, wherein a connecting line is provided along the cable route and in particular in the earthless duct for forwarding a heat transfer medium to a consumer and / or heat store.A system with a cable route according to any of claims 10 to 15, wherein the system further comprises a heat store and / or heat network, wherein the heat exchange element is directly or indirectly connected to the heat store and / or the heat network.Method for operating a cable route according to one of Claims 10 to 15, wherein the heat generated in the power cables is dissipated via the heat transfer medium.Method according to claim 17, wherein in the event of a heat requirement which is smaller than the heat obtained from the power cables, the excess heat is stored in a heat store which is preferably designed as a season store.Method according to claim 17 or 18, wherein in the case of a heat requirement which is greater than the heat obtained from the power cables, the additional heat requirement is taken from a heat store.

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