WO2007101682A2

WO2007101682A2 - Photovoltaic arrangement

Info

Publication number: WO2007101682A2
Application number: PCT/EP2007/001973
Authority: WO
Inventors: Werner Butzer
Original assignee: Energie Für Gebäude Gmbh & Co. Kg
Priority date: 2006-03-07
Filing date: 2007-03-07
Publication date: 2007-09-13
Also published as: WO2007101682A3; DE202006003596U1

Abstract

The invention relates to photovoltaic arrangements such as those mounted on roofs etc. for generating power from sunlight. Said arrangements consist mostly of a plurality of electrically interconnected individual solar cells and the direct current of said solar cells must be supplied to a current inverter which converts said generated direct current into an alternating current with the correct frequency and voltage of the network into which the current is fed. The inventive photovoltaic arrangement forms a connection box which is constructed in a simple, cost-effective and functionally secure manner, and by which means the strings of solar cells can be connected in a rapid and simple manner and can optionally also be mounted externally. Said connection box is used to connect the solar cells to a current inverter, and comprises a housing, safety fuses provided with safety bodies, and connecting terminals and cable inlets, the safety bodies of the fuses being direct current fuses.

Description

Fotovoltaikanlage

I. Field of application

The invention relates to photovoltaic systems, as they are mounted to generate electricity from sunlight on roofs, etc., usually consisting of a plurality of individual solar cells, which are electrically connected to each other and their DC must be supplied to an inverter, the DC generated in alternating current with the right one Converts the frequency and voltage of the network into which the current is subsequently fed.

II. Technical background

Since the inverters are relatively expensive and sensitive components, they are housed well protected inside the building in question and possibly also in a place to which not every unauthorized person has access, and therefore usually located at a greater distance from those on the roof solar cells.

In order to minimize the cabling effort, one or more connection boxes are installed - if possible in the vicinity of the solar cells - from which only one DL + and one DL line lead to the inverters.

As a rule, this happens in such a way that a certain number of individual solar cells are interconnected in series or in parallel, and the two End leads of such a so-called string of the junction box are supplied.

At the connection box a multiplicity of such line pairs of the individual strings arrives, which in the connection box are usually connected in parallel and individually protected. The individual cables are guided by means of known cable bushings through corresponding openings in the wall of the housing and clamped to the fuses or terminal strips of the connection box.

As fuses, although a DC current is to be monitored, preferably AC fuses are used, mainly because of the easier availability in the high-voltage range of above 500 volts; usually so many solar cells are combined into a string that their total voltage is approximately at 600 - 700 volts.

III. Presentation of the invention

a) Technical task

It is therefore an object of the invention to provide a junction box that is simple and inexpensive and reliable built by means of which the strings of solar cells can be connected quickly and easily and which may also be mounted outdoors.

b) Solution of the task

This object is solved by the features of claims 1 and 24. Advantageous embodiments emerge from the subclaims.

According to the invention it is proposed to use as fuses DC fuses instead of the commonly used AC fuses. It has been recognized that AC fuses can withstand only half of the rated DC voltage. In addition, the alternating current behaves differently from the direct current, because at zero crossing of the alternating current, the spark is extinguished, so it does not extinguish with direct current. Therefore, the fuse must be designed for DC voltage.

The connection box comprises a housing which is provided with cable passages through which the cables emerging from the connection box and / or arriving at the connection box are carried. The cable passages are designed as bolted cable passages or preferably in each case as a plug connector, wherein the plug connector consists of two plug parts, namely a male and a female plug part or a positive part and a negative part.

A plug part of the connector, preferably the positive part, is mounted in a housing opening. For this purpose, the plug part of the connector to be fastened can be equipped with an external thread and a counter nut for screwing the plug part into the housing opening, so that fastening in the housing opening can be as simple and fast as possible.

By screwing the male part to the housing using a locknut, if necessary, by interposing a seal such as a rubber sealing ring, waterproof attachment can be made to meet the high requirements of the respective class of protection when installing outdoor electrical equipment to live up to it. To replace a defective connector or a defective seal ring, the connector part can be removed by loosening the Schräubverbindung from the housing again. The positive or male plug part preferably comprises a bush which radially surrounds the electrical contact and protrudes further in the axial direction than the electrical contact.

Here, the socket on the one hand has the function to shield the electrical contact, for example, against ingress of water, and on the other hand, the function to ensure by the interaction with a corresponding receptacle in the female connector part that upon application of a lateral force on the connector the socket with a corresponding female plug part absorbs this force and prevents a contact pin of the male plug part from bending and thus permanently interrupting the electrical connection.

Preferably, the two connector parts and the fastening means for attaching the connector to the housing relative to each other are arranged so that the contacts of the connector are located within the housing and thus better protection> against external influences such as water, moisture or condensate is possible.

The positive and the negative plug part have a matching latching device to positively lock these two connector parts in the longitudinal direction, said latching connection is preferably designed as a detachable connection.

The advantage is that only with one hand and in a single assembly step, both an electrical connection and a mechanical connection between the two connector parts can be produced, which is especially advantageous during installation or retrofitting on site.

Alternatively, the locking connection ¹ between the male parts either alone by a relative movement in the longitudinal direction or axial direction, or by a composite relative movement in the axial and radial directions, ie a screwing done. The plug part, which is attached to the housing or in the housing opening of the housing, additionally has a cover with which the plug opening is completely protected against water and protected against unauthorized access by hand or a sharp rfietallischen object. This cover is removed before plugging in the other plug part. The cover is made of rubber or a plastic material and is held by a tab captive on the attached to the housing plug part.

To accommodate or accommodate the individual fuses backup shots are used, which are preferably provided in the form of swing-fuse housings, wherein a lid for locking the fuse housing is pivotally mounted on the fuse housing. In each case, in these fuse housings, there is a fuse holder in which the ends of the fuse body transversely to its longitudinal extent, in e.g. Clamps with two legs, are pressed.

A particular advantage is obtained when the fuse holder is fastened to the lid, in particular such that when opening the lid consisting of an electrically insulating material, the fuse holder is automatically removed from the respective current path together with the fuse. Consequently, the safety of the operator is improved, since the fuse does not have to be removed separately directly from the hot line, as may be the case during maintenance work.

The fuse holders are each attached to a lid. In this case, the fuse housings are preferably such that, when the lid is pivoted, the receiving space is closed before the fuse received in the lid reaches the electrical contacts, so that improved protection of the operator against touching electrically charged parts is achieved. The supply lines, ie the cables arriving from the solar cells or strings, which first pass through connectors in the housing apertures into the housing of the connection box as described above, are subsequently passed through cable passages in the fuse housings or also through connections which provide an electrical connection between outside the fuse housing and the inside of the fuse box enable, guided and connected to the respective fuses directly or via the fuse holder.

On the other hand, the fuses or the fuse holders are connected to a bus bar directly on the output side or via an output terminal which produces an electrical connection between the interior of the fuse box to the outside. This busbar is mounted in the housing of the connection box and combines all the outgoing connections of the fuses.

The busbar can also extend through side-by-side securing receptacles in order to electrically connect these securing receptacles to one another on the outgoing side, wherein a cable passage is formed only in one of these juxtaposed housings through which a cable can be led to the outside and with one end to the housing attached to the housing plug part is connectable.

Preferably, the housing used meets the protection class IP67. The fuse holders used are preferably loadable up to at least 650 volts, preferably up to 690 volts. The connectors for connecting incoming and away from the housing cable and in particular their implementation preferably also meet the protection class IP 67.

The housing of the junction box is further provided with a venting device and / or a pressure compensation device.

The venting device is designed so that when the temperature in the housing rises to a certain value, the housing is correspondingly connected Vent passages are opened and air circulation between the interior and the environment is achieved to cool the interior of the housing. The pressure compensation device is preferably provided in the form of a pressure compensation valve which does not exceed the pressure inside the housing, in particular when heated, to a predetermined value.

Through these measures, the operation of the connection box is possible regardless of extreme climatic conditions.

The connecting cables between the sockets and the fuse holders are preferably made of highly flexible cables according to VDE 0295 / Class 5 / IEC 60228 CI5. By using such flexible cables, the junction box can be made physically small.

A special compact connection box is created when the base area of the housing of the connection box is not more than three times the base area, in particular not more than 2.5 times the base area of the fuse holders and terminal strips installed in the box.

Preferably, the connection box is rectangular, wherein the securing receptacles and the terminal block are rastered on a locking rail screwed in the longitudinal center, and the securing receptacles begin close to one of the narrow-side outer walls and extend beyond the longitudinal center.

In the housing, a terminal strip is provided, to which all of the solar cells incoming negative or ground cables are brought together and then bundled in a single outgoing ground cable. The earth cable is in turn connected at one end to the connector part attached to the housing. Preferably, the terminal strips are latched to the clamping or locking rail for easier installation. The shorter or shorter edge length of the base area of the junction box is at most twice as long as the longitudinal extent of the individual fuse holders in the direction of current passage; This results in a particularly compact arrangement and assembly of the components, ie plug, cable, terminal strip, busbar, fuse holder, venting device, pressure compensation device, etc., without high space consumption.

In order to be able to connect the largest possible number of solar strings to a single connection box, the connection plugs for the solar cells are arranged on one of the longitudinal outer sides of the connection box. Preferably, the connectors are in two rows one above the other. arranged and wired that in half to a narrow side towards the positive pole connector and in half to the other narrow side towards the negative pole connector are arranged.

But it is also possible that in the half to one longitudinal side towards the positive pole and half in the other longitudinal side towards the negative pole connector are arranged. By these arrangements a clear as possible pin assignment is achieved, which allows the user a clear and quick assignment between the connector parts.

In an advantageous embodiment of the connection box, the screw connection of the clamping or latching rail at the bottom of the housing is such that it does not penetrate the housing. This can be avoided potential leaks on the housing.

The positioning of the terminal strips and fuse holders on the locking rail is selected in such a way that the screw connection of the clamping rails in the housing remains accessible in the case of latched and wired terminal strips and fuse holders. Thus, in the preassembly of the junction box, first a group consisting of clamping or locking rail, terminal strips and securing receptacles can be preassembled and then the subassembly can be assembled / screwed together as a whole in a single assembly step in the housing. A particularly dense enclosure is achieved when an annular circumferential seal is disposed between the lid and the housing and a bead projects upwardly from the housing within the seal towards the lid, which is overlapped by the downwardly bent edge of the lid.

If the lid is removed from the housing, the interior of the housing is completely released by the closable by means of the lid opening of the housing. Consequently, all mounting areas in the housing can be accessed directly with the lid open.

Finally, a solar cell system is proposed which is equipped with the connection box according to the invention. In this case, the cables between the solar cells or strings and the connecting box are preferably formed at both ends with the same type of plug connectors, possibly at one end a male or positive and at the other end a female or negative part of the plug connector.

c) embodiments

An embodiment according to the invention is described in more detail below by way of example. Show it:

1a is a plan view partially in section of the connection box according to the invention, wherein the cover of the housing is assumed;

Fig. 1 is a detail view in section of a connector in Figure 1 a including a cover ..;

FIG. 2 shows a side view of the connection box shown in FIG. 1a from the left; FIG. and Fig. 3 is a partially sectioned side view of one of the securing receptacles shown in Fig. 1a.

In Fig. 1 a, a junction box 1 according to the invention is shown. The junction box 1 consists of a housing 2, a plurality of fuses 3 (in particular 7 pieces in the figure), a plurality of terminal strips 4 (in particular 6 pieces in the figure) and a plurality of Dteckverbindern 5 (in particular 8 pieces in the figure).

The housing 2 is viewed in plan view rectangular with two opposite narrow sides and two opposite longitudinal sides. The housing 2 consists in particular of four side walls 2a-2d and a bottom part 18, in each case in the corner regions at the junctions of the side walls 2a-2d and additionally in the middle of the longitudinal side walls 2b and 2d threaded holes 19 for screwing a (not gezeig- th) covers are provided. The housing 2 is, with the exception of the lid, integrally formed of a plastic material.

In the housing 2, the fuses 3 and the terminal strips 4 are arranged side by side along the center line in the longitudinal direction of the housing 2, wherein the group of juxtaposed fuses 3 in Fig.1a and the group of juxtaposed terminal strips 4 adjacent to each other in the Housing 2 are arranged, and wherein the group of fuses 3 in the Fig.1a is located at the top and the group of terminal strips 4 in Fig.1a below.

The fuses 3, each having a fuse housing 6 and the terminal strips 4 are viewed in plan rectangular with narrow and long sides. The fuse housing 6 are arranged in the housing 2 so that each of the narrow sides of the fuse housing 6 of the longitudinal sides and the longitudinal side wall of the housing 2 are facing. Similarly, the terminal strips 4 are arranged in the housing 2 so that each of the narrow sides of the terminal strips 4 of the longitudinal sides and the longitudinal side wall of the housing 2 are facing. On the bottom part 18 of the housing 2, a latching rail 17 made of metal is screwed by means of screws 20 and extends centrally in the longitudinal direction of the bottom part 18. On the latching rail 17, in turn, the fuse housing 6 and the terminal strips 4 are locked, in particular such that they are not transverse to the locking rail 17 and in the longitudinal direction of the locking rails 17 are readily displaced.

As can also be seen from FIG. 1 a, a plurality of housing openings 13 a, b are provided on two opposite side walls and in particular on the longitudinal side walls 2 a and 2 c of the housing 2, wherein the housing openings 13 a on one side, i. on the left side in Fig. 1a, for feeding the cables (not shown) arriving from the solar cells (for guiding a direct current) into the housing 2, and the cable passages 13c on the other side, i. on the right side in Fig. 1a, for performing outgoing electrical cable from the housing 2 serve.

While on the side of the incoming cables, i. are provided on the left side of the housing 2, connector 5 in the housing openings 13a, are screwed on the side of the outgoing cable usual Kabelurchlasteile in the housing openings 13b

In the connection box 1 shown in Figure 1a the simpler Representation are seen for a total of only four cables, namely a solar module strand 22 for guiding the voltage of a solar module or solar string of the connector 5a for securing, a ground cable 23, between the mass Connector 5 a 'and one of the terminal strips 4 is connected, wherein a solar module strand or a strand of ground may lead to the fuse holder or the terminal block of each connector. Furthermore, on the outgoing side of the fuses 3 and the terminal strips 4 are each a power cable 24, which summarizes all arriving at the fuse housings solar module strings 22, .., .., and an outgoing ground cable 25, which summarizes all incoming to the terminal strips 4 ground cable 23, .., .. summarizes provided.

1b shows an enlarged view of the connector 5a in Fig.1a attached to a housing wall 2b state. The connector 5b has a connector housing 14. On the side of the housing 2 of the connection box 1, the plug housing 14 is provided with a cable passage part 25 with an external thread 11 which projects from the side of the connector housing 14 facing the connection box housing 2 and extends through a housing opening 13a into the connection box housing 2.

A union nut 12 is screwed onto the cable passage part 25 with external thread 11 so that the connector housing 14 is pressed against the outside of the connection box housing 2.

In the plug housing 14, which is cylindrical in shape and has a recess 14a in the peripheral surface, a connection pin or a plug contact 15a is accommodated. This plug contact 15a cooperates with a female plug contact, not shown, to establish an electrical connection.

In Fig. 1b, a connector cover 26 is further seen, which is held captive on the connector housing 14 by means of a tab and can be raised to close an unused connector part 5a on the front side, as shown in Fig. 1 a can be seen.

It should be noted that in the assembled state of the connector 5, when the positive 5a and negative connector part are plugged together, the recess 14a is completely closed in the connector housing by a female body of the negative connector part.

Fig. 2 shows a side view of the junction box 1 in Fig.1a. In this view, the housing 2, the associated cover 9 and in the longitudinal side wall 2a provided plug connector 5a and the connector covers 26, wherein for the purpose of illustration in the right lower connector, the connector cover 26 is removed.

2, a total of two connector rows are provided in the longitudinal direction, each one connector row for connecting the current-carrying solar module strands and serves the other connector row for connecting the respective ground cable, each adjacent solar module and ground strands a solar module or a solar string assigned. Consequently, the embodiment shown in Fig. 2, a maximum of eight solar modules or solar strings can be connected.

Fig. 3 shows a fuse or fuse holder 3 in a sectional side view. The fuse 3 comprises a fuse housing 6 having a fuse cover 28 pivotally mounted on the fuse housing 6 and mounted about an axis of rotation 27 for closing an opening formed in the top of the fuse housing 6.

On the underside of the fuse cover 28, a fuse holder 7 is formed, wherein by the holder 7 shown in the figure, a positive connection between the (indicated by the solid line) fuse body 8 and the fuse cover 28 is possible. The fuse cover 28 has an L-shaped cross section, with a projection 7c extending perpendicularly from the distal end of the shorter leg 7b parallel to the longer eye 7a. Between the longer leg 7a and the projection 7c, the securing body 8 is arranged with one end and is held by the shorter leg 7b in the longitudinal direction.

The opposite end of the fuse body 8 is held in the longitudinal direction by a projection 7d protruding perpendicularly from the longer leg 7a of the fuse cover 28. As indicated by the dashed lines in Fig. 3, the fuse body 8 is first slid obliquely to the longer leg 7a of the fuse cover 28 with one end in the lower receptacle and simultaneously moves the opposite end of the fuse body 8 in the direction of the fuse cover 28. The distance between the shorter leg of the securing holder 7b and the projection 7d formed at the opposite end perpendicular to the longer leg is such that the securing body is frictionally held therebetween.

The fuse or fuse holder 3 also has two electrical contacts, a positive contact 10a and a negative contact 10b, where the terms "negative contact" and "positive pole contact" is not the voltage potential to understand the ground potential but to be bridged by the fuse body contacts the current-carrying current path.

In the closed state of the fuse cover, the two contacts 10a and 10b bridged by the fuse body 8 (dashed) line and thus closed the current path. When opening the fuse cover 28, as shown by the solid line, the fuse body is removed from the current path and thus interrupted the current path.

At the top of the fuse cover 28, a handle portion 29 is integrally formed, on which the hand of an operator to open and thus interrupt the current path can attack. On the underside of the fuse housing 6, two recesses 30a, 30b are each formed with the middle of the housing 2 from the outer lower side of the recesses 30a and 30b projecting projections 31a and 31b, in which each of the outer upwards and then angled outwards again Ends 17a and 17b of the locking rail 17 are latched. LIST OF REFERENCE NUMBERS

1 junction box 26 connector cover

2 housing 27 axis of rotation

3 fuses 28 fuse cover

4 terminal strips 29 handle part

5 connectors 30a, b recesses

5a positive or male plug-in part 31 a, b projections

5a 'grounding connector

6 fuse box

7 fuse holder

8 fuse body

9 lids

10a recording contact

10b recording contact

11 external thread

12 union nut

13a, b housing breakthrough

14 connector housing

14a recess

15a plug contact

16 connection line

17 latching rail

18 bottom part

19 tapped holes

20 screws

21 cable passage part

22 solar module string

23 ground cables

24 outgoing power cables

25 cable passage part

Claims

protection claims

1. Connection box (1) for connecting solar cells to an inverter, with a housing (2),

Fuses (3) with fuse bodies (8), - terminals,

Cable inlets, characterized in that the fuse body (8) of the fuses (3) are DC fuses.

2. Connection box (1) according to claim 1, characterized in that the cable inlets, in particular on the access side of the connection box (1) as

Connectors (5) are executed.

3. Connection box (1) according to claim 1, characterized in that the cable inlets are designed as a cable gland (cable bushing).

4. Connection box (1) according to any one of the preceding claims, characterized in that the fuses (2) each comprise a fuse holder having a fuse housing (6) and a fuse holder (7), and the fuse holder (7) is a swing-fuse holder which presses the ends of the securing body (8) transversely to its longitudinal extent in brackets.

5. junction box (1) according to one of the preceding claims, characterized in that the fuse holder (7) are such ^'that already closes the receiving space during pivoting closed the fuse cover (18) before the securing cover (18) fuse body (taken out 8) reaches the electrical receptacle contacts (10a, 10b).

6. Connection box (1) according to one of the preceding claims, characterized in that the outgoing poles (-) of all fuse holders (7) are electrically connected to each other by means of a busbar.

7. Connection box (1) according to one of the preceding claims, characterized in that a part of the connector (5), in particular the positive part (5a), with an external thread (11) and a lock nut (12) is equipped for screwing in a housing opening (13).

8. Connection box (1) according to one of the preceding claims, characterized in that the positive plug part (5a) comprises a socket housing (14) which radially surrounds the electrical contact (15) of the positive part (5a) and in the axial direction on protrudes as the electrical contact (15).

9. Connection box (1) according to any one of the preceding claims, characterized in that positive (5a) and negative part have a matching latching device for the positive locking in the longitudinal direction.

10. Connection box (1) according to one of the preceding claims, characterized in that the housing (2) meets the protection class IP 67.

11. junction box (1) according to any one of the preceding claims, characterized in that the fuse holder used (7) to at least 650 volts, preferably 690 volts, preferably 1,000 volts, are resilient.

12. Connection box (1) according to one of the preceding claims, characterized in that the cable connectors (5) and in particular their passage through the housing (2) meets the protection class IP 67.

13. Connection box (1) according to one of the preceding claims, characterized in that the housing (2) has a pressure compensation element, which is in particular such that an air exchange between the interior of the housing (2) and the environment takes place while the penetration is prevented by water.

14. Connection box (1) according to one of the preceding claims, characterized in that the connecting lines (16) between the positive connector parts (5a) and the fuse holders (7) consist of double-insulated cables of fine-stranded strands and a bending radius down to 4 times allow the metallic pipe diameter.

15. Connection box (1) according to one of the preceding claims, characterized in that the base of the housing (2) of the connection box (1) no more than three times the base area, in particular not more than 2.5 times the base area in the housing (2) installed fuse housing (6) and terminal strips (4).

16. Connection box (1) according to one of the preceding claims, characterized in that the smaller edge length of the base surface of the housing (2) is at most twice as large as the longitudinal extension of the individual fuse housing (6) in the current passage direction.

17. Connection box (1) according to one of the preceding claims, characterized in that the housing (2) is rectangular and fuse housing (6) and terminal strips (4) are rastered on a screwed in the longitudinal center locking rail (17).

18. Connection box (1) according to one of the preceding claims, characterized in that the fuse holders (7) begin near to one of the narrow-side outer walls and extend beyond the longitudinal center.

19. Connection box (1) according to one of the preceding claims, characterized in that the plug connectors (5a) for the solar cells. one of the longitudinal outer sides of the housing (2), in particular in two rows one above the other, are arranged and wired so that in the half to a narrow side towards the positive pole and half of the other narrow side towards the negative pole connector are arranged.

20. Connection box (1) according to one of the preceding claims, characterized in that the screw connection of the latching rail (17) does not penetrate the bottom part (18) of the housing (2).

21. Connection box (1) according to one of the preceding claims, characterized in that the positioning of the terminal strips (4) and fuses (2) on the latching rail (17) is selected so that the screw, the latching rail (17) in the housing ( 2) remains accessible with the terminal strips (4) and fuses (2) snapped on and wired.

22. Connection box (1) according to any one of the preceding claims, characterized in that the through the lid (9) closable opening of the housing (2) completely releases the interior.

23. Connection box (1) according to one of the preceding claims, characterized in that between the cover (9) and housing (2) an annular circumferential seal is arranged and from the housing (2) within the seal a bead upwards in the direction of the cover (9 ), which is overlapped by the .nach bent down edge of the lid (9).

24. Solar cell plant with

Solar cells, at least one connection box (1), at least one inverter, and connecting cables, characterized in that the connection box (1) is designed according to one of the preceding claims.

25. Solar cell system according to claim 24, characterized in that the cables between the solar cells and the junction box (1) at both ends in each case with the same type of connectors (5), optionally at one end a male (5a) and at the other End of a female part of this connector (5), are formed.