WO2016188584A1

WO2016188584A1 - Arrangement for the transmission of electrical energy

Info

Publication number: WO2016188584A1
Application number: PCT/EP2015/061870
Authority: WO
Inventors: Hans-Joachim Knaak
Original assignee: Siemens Aktiengesellschaft
Priority date: 2015-05-28
Filing date: 2015-05-28
Publication date: 2016-12-01
Also published as: EP3278414A1

Abstract

The invention relates to an arrangement (1) for transmitting electrical energy, comprising an electrical cable (3) which has at least one cable section (3b) arranged below a surface (9) of a body of water (5) and above the bed (7) of said body of water (5).

Description

description

Arrangement for transmitting electrical energy The invention relates to an arrangement for transmitting electrical energy with an electrical cable. By means of an electric cable, electrical energy can be transmitted over long distances. It may be necessary, at least partially, for electrical cables in a body of water

(for example, in a river, a lake, a sea or an ocean).

Often electrical cables are laid on the bottom of the water. Especially in deep waters (sea, ocean o. Ä.) The cables have to withstand a considerable water pressure. The cables must be robust accordingly

be executed and are therefore expensive.

The invention has for its object to provide an arrangement with which electrical energy can be transmitted inexpensively through water.

This object is achieved by a

Arrangement according to the independent claim. Advantageous embodiments of the arrangement are in the dependent

Claims specified.

Disclosed is an arrangement for the transmission of

electrical energy with an electrical cable having at least one cable section which is arranged below a surface of a body of water and which is arranged above the bottom of the water body. At this

Arrangement is particularly advantageous in that the electrical cable has one or more cable sections, although below the surface, but above the bottom of the

Water body are arranged. Due to the smaller depth, this cable section is exposed to a lower water pressure than a cable section located at the bottom of the water is arranged. Therefore, this cable section can be designed to be less pressure-resistant, which can be produced cheaper this cable section. In other words, the at least one cable section is free of ground contact.

The arrangement may be such that the sum of the lengths of the cable sections is at least 80% of that in the

Body of water running cable length corresponds. At this

Variant of the arrangement may run less than 20% of the running in the water cable length at the bottom of the water. This is particularly beneficial for waters that have very shallow areas (for example, mudflats in the North Sea). In such shallow water areas, the cable may well be deposited on the bottom of the water. This is not a problem in terms of the required compressive strength of the cable, since only very low water pressures occur at very shallow depths.

The arrangement can also be designed so that the running in the water cable length is at least 5 km.

Particularly advantageous is the arrangement with cable lengths from 5 km in length, because with such extensive waters at their bottom often considerable depths and thus strong

Pressure loads occur. In addition, the cost of the cable play a major role in such a large cable lengths.

The arrangement can be designed such that the

Cable section extends substantially horizontally. Due to the substantially horizontal course of the cable section is achieved that at all points of the cable section in

Essentially the same water pressure occurs. Since cables usually over long lengths have the same structure and thus the same compressive strength, the

Cable section are dimensioned to this intended water pressure out, so that the cable section on the one hand easily withstands the intended water pressure, however on the other hand, an unnecessary (pressure-related)

Oversizing the cable section is avoided.

The arrangement may in particular be designed such that the cable section (below the surface of the body of water) is arranged at a depth that is at least L / 4. The depth is therefore at least 25% of L. Here, L is the mean wavelength (typical wavelength) of on the

Waters occurring waves. It has been found that at a depth of at least L / 4 (that is to say at a depth which corresponds to at least one quarter of the mean wavelength L), the movement of the water particles through the waves has already significantly decreased. As a result, the one or more cable sections, which are located at a depth of at least L / 4, only slightly moved by the waves occurring on the water and are therefore burdened by the waves only slightly mechanical.

This applies in particular to so-called deep water.

Deep water is water in which the total water depth is greater than half the wavelength L. If single large waves with a longer wavelength than the average wavelength L occur, this is not a problem. It goes with the

disclosed arrangement is not about to avoid any stress of the cable by waves. Rather, it is about keeping the average stress of the cable low, so that the life of the cable due to a lower

medium stress is increased. Advantageously, the arrangement can also be designed such that the cable section (below the surface of the

Body of water) at a depth that is at least L / 2 (ie at least 50% of L). Where L is the mean wavelength of waves appearing on the water. If the cable section (s) are arranged at a depth that is at least half the wavelength of waves appearing on the waterway, then the

Water particles at this depth by the waves only very much little moves. For example, cases occur where, at a depth of L / 2, the movement of the water particles is only approx. 5%, based on the movement of the water particles at the water surface. The arranged at a depth of at least L / 2 cable sections are therefore by the

Waves moved very little and are therefore exposed to only very low mechanical loads due to the wave movements. This applies in particular to deep water. This helps to make the cable sections extra

can be produced inexpensively.

The arrangement can also be designed so that the

Cable section (below the surface of the water body) is arranged at a depth which is at least 48 meters. A depth of at least 48 meters is particularly advantageous for the arrangement of the cable sections, because the

Cable sections at this depth do not hinder the shipping traffic. Usually today's ships have a maximum draft of about 24 meters. At a

Laying at a depth of at least 48 meters there is a large safety distance between the keel of the ships and the routed cable sections. Furthermore, when laying at a depth of at least 48 meters there is still a sufficiently large safety distance to future ships, which may have a greater draft.

The arrangement can be designed such that the

Cable section (below the surface of the water) is located at a depth that is a maximum of 1000 meters. The cable section can therefore be arranged, for example, at a depth which is between 48 and 1000 meters. A depth of a maximum of 1000 meters has proven to be advantageous because at depths greater than 1000 meters, the cost of upgrading the cable for the water pressures occurring at such depths increases sharply.

The arrangement can be designed such that the

Cable section by means of at least one at the bottom of the Body of water attached to the rope below the surface of the body of water. In this arrangement, a

Floating cable section held by the rope below the surface of the water. It has the

Cable section has a density that is less than the density of water. This density can be achieved by an appropriate choice of material of the cable section.

The arrangement can also be designed so that the

Cable section is assigned at least one buoyant body. By means of this buoyant body can be advantageously achieved that the cable section floats in the water and does not sink to the bottom of the water. The buoyant body serves to generate a buoyancy force in order to keep the or the cable sections groundless.

Often, a plurality of buoyancy bodies are used to keep the cable portion groundless. Of the

Buoyancy can also be referred to as a floating body. The buoyancy body or float can float on the surface of the water body or below the surface of the water body.

The arrangement can also be designed so that the

Float floating on the surface of the water. At such on the surface of the water

Floating buoyant body can hang a cable section, so that the cable section does not sink to the bottom of the water. Often, the cable section depends on a plurality of such buoyant bodies.

The arrangement can also be designed so that the

Cable section is associated with at least one pump for pumping a fluid, and the pump is connected by means of a fluid line to the buoyant body. By means of this pump, a fluid, in particular a gas, can be pumped into the buoyant body. As a result, water is forced out of the buoyant body, whereby the buoyant body in different Depths of the water can be positioned (similar to a submarine).

The arrangement may be configured such that the cable is a high voltage cable, in particular a high voltage DC cable. The arrangement is special

cost-saving for high-quality high-voltage cables,

especially in high-voltage DC cables, such as those used in high voltage direct current transmission links.

The arrangement may also be configured such that a first end of the cable is electrically connected to a rectifier and a second end of the cable is electrically connected to an inverter. With this arrangement can be advantageous high-voltage direct current (HVDC) realize in which the cost of the electrical cable are significantly reduced.

Further disclosed is a high-voltage transmission device with an arrangement according to the

variants described above. The high-voltage transmission device may in particular be a high-voltage DC transmission device. Also disclosed is a method of transmitting

electrical energy, in which the electrical energy is transmitted by means of an arrangement according to the variants described above. In this method, electrical

Energy are transmitted in particular by means of high voltage direct current.

In the following the invention is based on

Embodiments explained in more detail. 1 is an embodiment of a in a

Waters laid electrical cable, in Figure 2 shows an embodiment of a in a

Waters laid electrical cable in conjunction with a wind turbine, in Figure 3, an embodiment of an electric

Cable laid at a depth of at least L / 4 (where L is the mean length of waves appearing on the water), in Figure 4 another embodiment of a cable laid at a depth of at least L / 2 an embodiment of an arrangement in which the electrical cable depends on floats, in

Figure 6 shows an embodiment of an arrangement in which the electrical cable is provided with buoyancy bodies, and in

Figure 7 shows an embodiment of an arrangement in which the electrical cable is fixed by means of cables at the bottom of the water.

1 shows schematically an embodiment of an arrangement 1 for transmitting electrical energy by means of an electric cable 3 is shown. The electric

Cable 3 is arranged in a body of water 5. Recognizable is the bottom 7 of the water body 5 and the surface 9 of the water body 5 (water surface 9) and a first bank 11 of the water body and a second bank 13 of the water body. The electrical cable 3 extends from the first bank 11, starting through the water 5 to the second bank 13. Only in the area of the first bank and the second bank of the cable 3 touches the bottom of

Water body (ie the solid ground below the water). During the course of the cable from the first bank 11 to the second bank 13, the cable extends below the surface 9 of the body of water and above the bottom 7 of the body of water. Thus, the cable 3 has three different cable sections. A first cable section 3 a extends in the first bank 11 to

Waters 5 out. A second cable section 3b extends below the surface 9 of the water body and above the bottom 7 of the water body (in the direction of the second bank 13). A third cable section 3c extends in the second bank 13. The second cable section 3b is free of ground contact, i. he does not touch the bottom 7 of the waters 5. The

Cable section 3b is substantially horizontal, i. it runs horizontally. Therefore, the cable portion 3b is arranged substantially at a constant depth (below the surface 9 of the water).

It is advantageous that in depth 15 of the

Cable section 3b, the water pressure (hydrostatic pressure) is lower than at the bottom 7 of the water. Furthermore, it is advantageous that when laying the cable above the

Reason of the water body may be a contact between the cable and possibly at the bottom of the water body

undersea rocks is avoided, causing the

Life of the cable increased. Furthermore, one bypasses the problem that the bottom of the water is not always flat, but that sometimes there are very steep "mountains" or "slopes", which increases the length of the water

laying cable significantly increased. By an im

Essentially horizontal arrangement of the cable in the water (that is, a "floating" arrangement of the cable in the water, so to speak) can be the electrical connection with a minimum length of the cable section 3b realize.

In Figure 1, only one cable section is shown, which is below the surface 9 and above the bottom 7 of the

Water body 5 is arranged. In other embodiments, however, the cable 3 may also have a plurality of cable sections, which are arranged below the surface 9 and above the bottom 7 of the body of water 5.

FIG. 2 shows a further exemplary embodiment in which a wind power plant 202 on the body of water 5

is arranged. The wind turbine 202 is anchored by means of a schematically illustrated pile 204 in the bottom 7 of the body of water 5. The wind turbine 202 has a generator which generates alternating current. The alternating current is raised to a high voltage level by means of a transformer

transformed. Thereafter, the alternating current by means of a arranged on the wind turbine rectifier 206 in

DC converted. The resulting high-voltage direct current is arranged via the cable 3 to one on the second bank 13

Inverter 208 transmitted. Similar to the

Embodiment of Figure 1, the cable 3 a

Cable section 3b, which extends below the surface 9 of the water body and above the bottom 7 of the water body. This cable section 3b is ground free and runs substantially horizontally. By means of the rectifier 206, the cable 3 and the inverter 208 is a

High-voltage direct current (HVDC) transmission realized by means of which the power generated by the wind turbine 202 can be transmitted to the second bank 13 with low loss. The running in the waters 5 cable length of the cable 3 is 5km in this embodiment, in others

However, this cable length can also be up to several hundred kilometers.

In the exemplary embodiment of FIG. 2, the length of the second cable section 3b essentially corresponds to that in FIG

Waters 5 running cable length. In other

Embodiments may be the length of the second

Cable section 3b but also be significantly shorter than the total running in the water cable length. This is the case, for example, when the second bank 13 of the Water body runs very flat (for example, a watts is available) and the cable 3 rests in the region of the second bank 13 in appreciable length on the bottom of the shallow shore. It is advantageous if the cable sections extending horizontally and above the ground have, in total, a total length which corresponds to at least 80% of the cable length running in the water.

FIG. 3 shows an exemplary embodiment in which a wave 302 is shown schematically on the water surface 9. The shaft 302 has the wavelength L. in the

Embodiment of Figure 3, the second runs

Cable section 3b at a depth which is greater than a quarter of the wavelength (ie greater than L / 4) of the shaft 302. At such a depth greater than or equal to L / 4 has the

Movement of the water particles by the shaft 302 already strongly removed, so that the second cable section 3b is moved by the shaft 302 only slightly. Thus, only a small mechanical load of the second cable section 3b through the shaft 302 occurs.

FIG. 4 shows an exemplary embodiment in which the second cable section 3b extends at a depth

or is arranged, which is at least L / 2. L is the mean length of on the water

occurring waves 302. At a depth greater than or equal to L / 2 occur only very small movements of

Water particles due to the shaft 302, so that the second cable section 3b is very little moved by the shaft 302. Therefore, only very small mechanical loads of the second cable section 3b through the shaft 302 occur.

Preferably, the cable portion 3b is at a depth

arranged at least 48m. As a result, the cable section 3b does not interfere with shipping because today's ships have a maximum draft of about 24m

exhibit. Furthermore, the cable section 3b

advantageously at a depth of at most 1000m

be arranged. With a maximum depth of 1000m is the occurring water pressure at a reasonable cost for the cable technically easy to control. At depths of about 700m to a maximum of 1000m is advantageous that the cable section 3b rarely comes into collision with fishing nets, because most fishing nets are used at far lower depths than 700m.

FIG. 5 shows another arrangement with the cable 3

shown. The second cable section 3b is attached by means of cables 502 to buoyancy bodies 504, which are designed as floating bodies 504. Thus, it is prevented that the second cable section 3b drops to the bottom 7 of the water. Because the ropes 502 are all substantially the same length

2, it is achieved that the second cable section 3b is substantially horizontal below the surface of the

Waters and above the bottom of the water course.

It is further advantageous that the floating body 504 indicate the course of the second cable section 3b in the water, so that, for example, skipper on the

History of the second cable section 3b are informed.

In Figure 5, a plurality of buoyancy bodies 504 and a plurality of ropes 502 are shown. In individual cases, however, even a single rope with a single

Buoyant body be sufficient to the second

Cable section 3b above the bottom of the water

(non-contact) to keep. In another

Embodiment, the arrangement could thus be realized with only one buoyancy body 504.

The second cable section 3b can be gimballed to the buoyancy bodies, so that the second cable section 3b, even with shaft movements its original position

maintains. The buoyant bodies can also be like one

Semi-submersible be configured, ie the buoyancy bodies can a large volume below the water surface and a smaller volume above the water surface exhibit. Between the two volumes, one or more small volume fasteners are arranged. Such a half-diver is insensitive to wave motion. Laying a cable by means of buoyancy bodies floating beneath the surface of the water body is, for example, advantageously applicable in the Mediterranean. The electrical cable with the buoyant bodies would then sink to a certain depth, where an equilibrium of forces between the weight and the buoyancy force develops.

FIG. 6 shows a further exemplary embodiment in which the second cable section 3b, by means of at least one buoyant body 602, floats between the bottom of the

Body of water and the surface of the body of water. The buoyancy bodies 602 are each connected to a pump 606 by means of a fluid line 604. The pump 606 serves a fluid (for example, a gas) in the respective

To pump buoyant body 602 and so regulate the floating depth of the buoyant body 602 (and thus the floating depth of the second cable section 3b) in the water. This swimming level adjustment (swimming depth adjustment) is similar to a submarine. The buoyancy bodies 504 and 602 serve for

Generating a buoyant force to keep the cable section 3b free of ground contact.

For a single buoyant body may be sufficient; however, often a plurality of buoyant bodies are used. In another embodiment, the arrangement could also be realized with only one buoyancy body 602 and only one pump 606. FIG. 7 shows a further exemplary embodiment in which the second cable section 3b is held below the surface 9 of the body by means of one or more cables 702. One end of the cable 702 is connected to the Cable section 3b connected, the other end of the cable 702 is attached (for example by means of an anchor 704) to the bottom 7 of the water. Such a hold of the

Cable section 3b by means of at least one rope and

at least one anchoring (or weight) at the bottom 7 can be used, for example, for the laying of the cable in the (relatively shallow) North Sea.

In all embodiments, the cable 3 a

High voltage cables, in particular a high voltage

Be DC cable. The arrangements described form, for example, a high-voltage transmission device, in particular a high-voltage DC transmission device. By means of these arrangements, electrical energy can be transmitted. It can the

Transmission of electrical energy, in particular in the form of a transmission of high-voltage direct current, so that a high-voltage transmission, in particular a high-voltage direct-current transmission, can be realized.

Arrangements and methods have been described with which electrical energy can be transmitted in a cost-effective manner through bodies of water. This is achieved in particular in that an electrical cable has one or more cable sections, which are arranged both below the surface of the water body and above the bottom of the water body.

Claims

claims

1. Arrangement (1) for the transmission of electrical energy

- With an electrical cable (3) having at least one cable section (3b) which is arranged below a surface (9) of a body of water (5) and which is arranged above the bottom (7) of the body of water (5).

2. Arrangement according to claim 1,

d a d u r c h e c e n c i n e s that

- The cable section (3b) is free of ground contact.

3. Arrangement according to claim 1 or 2,

d a d u r c h e c e n c i n e s that

- The sum of the lengths of the cable sections corresponds to at least 80% of the running in the water cable length.

4. Arrangement according to claim 3,

d a d u r c h e c e n c i n e s that

- the length of cable running in the water is at least 5 km.

5. Arrangement according to one of the preceding claims, characterized in that a

- The cable section (3b) extends substantially horizontally.

6. Arrangement according to one of the preceding claims, characterized in that a

- The cable section (3b) is arranged at a depth which is at least L / 4, where L is the average length of waves (302) occurring on the water body (5).

7. Arrangement according to one of the preceding claims, d a d u r c h e c e n e c i n e that t

- The cable section (3b) is arranged at a depth which is at least L / 2, where L is the average length of waves (302) occurring on the water body (5).

8. Arrangement according to one of the preceding claims, characterized in that a

- The cable section (3b) is arranged at a depth which is at least 48 meters.

9. Arrangement according to one of the preceding claims, characterized in that a

- The cable section (3b) is arranged at a depth which is a maximum of 1000 meters.

10. Arrangement according to one of the preceding claims, characterized in that a

- The cable section (3b) by means of at least one at the bottom (7) of the body of water (5) fixed rope (702) below the

Surface (9) of the body of water (5) is held.

11. Arrangement according to one of the preceding claims, characterized in that a

- The cable portion (3b) is assigned at least one buoyancy body (504, 602).

12. Arrangement according to claim 11,

d a d u r c h e c e n c i n e s that

- The buoyancy body (504) on the surface (9) of the body of water (5) floats.

13. Arrangement according to claim 11 or 12,

d a d u r c h e c e n c i n e s that

- the cable section (3b) is associated with at least one pump (606) for pumping a fluid, and

- The pump (606) by means of a fluid line (604) is connected to the buoyant body (602).

14. Arrangement according to claim 1, wherein:

- The cable (3) is a high voltage cable, in particular a high voltage DC cable.

15. Arrangement according to one of the preceding claims, characterized in that a

- A first end of the cable (3) electrically with a

Rectifier (206) and a second end of the cable (3) is electrically connected to an inverter (208).

16. High-voltage transmission device with an arrangement according to one of claims 1 to 15.

17. A method for transmitting electrical energy, in which electrical energy is transmitted by means of an arrangement according to one of claims 1 to 15.