EP2580783A2

EP2580783A2 - Solar power plant with increased useful life

Info

Publication number: EP2580783A2
Application number: EP11738590.6A
Authority: EP
Inventors: Uffe Borup; Frerk Haase
Original assignee: Danfoss Power Electronics AS
Current assignee: SMA Solar Technology AG
Priority date: 2010-06-09
Filing date: 2011-06-09
Publication date: 2013-04-17
Also published as: CN203434163U; US20130099580A1; DE102010023262A1; WO2012000496A2; WO2012000496A3

Abstract

The invention relates to an arrangement (1, 14, 20) having at least one electric potential-varying device (12, 16, 17, 17') for varying the electric potential of at least one electrical device (2, 2', 4, 15, 15') with respect to earth potential, and a technical room arrangement. In the operating state, the electric potential-varying device (12, 16, 17, 17') is disposed in the technical room arrangement (8).

Description

Solar power plant with increased service life

The invention relates to an arrangement (technical arrangement), which has at least one electrical potential change device for changing the electrical see potential of at least one electrical device to ground potential.

In particular, due to environmental problems, and partly due to the associated public funding, the number of solar power plants in which direct electrical power is generated using solar photovoltaic elements is increasing. The size of such solar power plants can range from relatively small-scale facilities, such as on a house roof for (partial) supply of a single or multi-family house with electrical energy to large power plants with a power output of several megawatts and beyond.

Since photovoltaic cells can only generate direct current due to the design, but on the other hand, customary electrical loads are designed for alternating voltage (typically 230 V / 50 Hz or 110 V / 60 Hz), it is necessary to first convert the electrical direct current generated by the photovoltaic cells into alternating current , For this purpose, so-called inverters are commonly used in the current state of the art. Another advantage in the generation of AC voltage is (especially in larger solar power plants) that AC voltage can be transformed, and thus at a correspondingly high voltage, the electric current can be transported over relatively large distances without excessive losses. In practice, it has been shown that in solar power plants, under certain conditions, unexpectedly early deterioration of the grades of solar cells, can lead to a degradation of solar cells to the failure of solar cells.

This applies in particular when so-called thin-film solar cells are used. Although the underlying processes are not fully understood, it has been found in practice that this problem occurs especially when (parts of) the solar cells are operated with negative bias against their environment. This leads to electric fields contrary to the intended field direction. In the case of thin-film solar cells, the effect is non-reversible. Accordingly, there is a degradation or destruction of the solar cell.

Even in the case of back-contacted solar cells (often referred to by the term "backside contacted solar cells"), similar problems occur. He has shown in practice that in an operation of back contacted solar cells under an unfavorable electrical potential whose efficiency can deteriorate comparatively quickly. This is known as the so-called "polarization effect". An unfavorable electrical potential is present in the case of back-contacted solar cells (in contrast to thin-film solar cells) if parts of the back-contacted solar cell are operated with a positive bias relative to their surroundings. Although the polarization effect is usually reversible, it is desirable to avoid the relatively time-consuming regeneration phases. In order to avoid thereby caused degradation, deterioration, deterioration of the action or damage, has already been proposed in the prior art that parts of the solar power plant, in particular the solar cells are brought to a certain potential to earth using a voltage source. This is possible in particular because the voltage transformation transformers, which are usually provided anyway, also have galvanically separating properties. Thus, a bias can be provided without this on the electrical transmission lines would have to be considered. Even if no transformer were required per se, a galvanic isolator (which resembles a voltage-transforming transformer in its design) can nevertheless be used in order to be able to achieve essentially any desired bias voltage here as well. Such systems are described, for example, in German Utility Model DE 20 2006 008 936 U1, in US Patent Application US 2009/0101191 A1, in European Patent EP 2 136 449 B1 and in International Publication WO 2010/051812 A1.

Although the systems described therein are fundamentally functional, they still have disadvantages. For example, the DC voltage sources described there are usually relatively numerous, expensive, complex and complex. This not only affects the sources themselves, but also the installation. Often there is no adequate security against breakdowns, vandalism and / or theft. Furthermore, a remote control of the DC voltage sources used there often proves difficult.

The object of the invention is thus to propose a comparison with the prior art improved arrangement with at least one electrical potential change device.

The invention solves the problem. It is proposed that an arrangement which has at least one electrical potential change device for changing the electrical potential of at least one electrical device to ground potential, and which additionally has at least one equipment room device, is designed such that the electric potential change device in the operating state at least partially in the at least one equipment room device is arranged. It is usually necessary in such systems anyway that a technical room equipment must be provided. In all re- Gel is also available in this equipment room device sufficient space to accommodate more components in it. Even in the event that the equipment room equipment needs to be (slightly) planned larger, the associated costs usually increase significantly less than the available space or space increases. However, if the electrical potential-changing device is located in such a tool room, then it is possible, for example, for the housing of the electrical potential-changing device to be made simpler and less expensive. Further advantages may also result from the proposed training in a simple manner. For example, technical room equipment is usually provided at more central points or for central and / or essential technical components. Thus, if the electric potential changing device is (partially) provided in a technology room device, the electric potential changing device is also usually in or adjacent to such a central point. This makes it possible, for example, that an external control (which may optionally be done by telecontrol principles and / or by manual intervention) is easier. In particular, components which are often required anyway can be resorted to. Also, if necessary, the number of cables to be laid can be reduced, which can not only reduce costs in terms of cables, but in particular also laying costs. Furthermore, due to the equipment room equipment, there is generally greater protection against environmental influences, vandalism, interference or theft. As a result, the entire, resulting arrangement can also have a higher level of operational reliability. A particularly great advantage in the case of a central arrangement (in particular in electrical terms, but possibly also additionally or alternatively in geometric terms) of at least one electrical potential change device can result if (protective) switches and / or fuses are provided in real systems ( which is usually the case). If, for example, one of the fuses provided burns out, then in the case of a central arrangement of the electrical potential-changing device, only borrowed lying behind the corresponding fuse part of the system electrically separated from the electrical potential change device. On the other hand, if the at least one electrical potential changing device were arranged in a "secondary branch", almost all parts of the plant (apart from the secondary branch) would be electrically disconnected from the electrical potential changing device when a fuse burned through, which would generally be much more disadvantageous.

Moreover, by virtue of the design within the equipment room device, it is also possible to be able to protect the potential change device against external temperature influences, for example. In particular, when a battery is provided, the reliability of the arrangement can be increased here. It is also possible to dimension the potential-changing device, in particular a battery used for this purpose, larger in order to be able to keep larger safety margins in stock in this way.

It is preferred if the at least one equipment room device is at least partially designed as a building device and / or as a closable device and / or at a central location. A building device can be designed, for example, in the form of a small house (for example a transformer house known per se), as a container device, as a cellar facility and / or as an optionally closed room in a larger building. Regardless of the training as a building device, a particularly high weather protection, a particularly great protection against vandalism and other damage, but also a protection against accidental touching and the like can be realized. Often, such building facilities are provided in connection with solar power plants and other technical devices anyway, in particular to accommodate certain technical equipment (for example, transformers, transmission electronics and the like), but also to use them as a control room and / or as a break room. In principle, however, the technical room equipment can also be designed otherwise, for example as a control cabinet or the like. Under one ner lockable device is in particular a backup by a lock (mechanical key, electronic access) and the like to understand. Depending on the type of locking mechanism different security levels can be realized here. Attaching the equipment room equipment in a central location can shorten the distances (both for cables to be laid and for the operator, who may be in close proximity, if necessary, especially when performing certain monitoring tasks) and the like. It is advantageous if the at least one equipment room device serves to at least partially accommodate further components, such as, in particular, transformer devices and / or inverter devices. As a result, in particular costs can be saved, since the equipment room equipment, in particular for the components mentioned, for example, for reasons of security against passers-by (in particular protection against accidental contact) and the like must be provided anyway. Usually, the electric potential varying device can be accommodated without further modifications in the engineering space device. If necessary, however, it may also be necessary to dimension the technical room equipment, for example, a little larger than usual. In addition, in particular, transformer devices and / or inverter devices generate a certain amount of waste heat during operation. This waste heat can be used for heating purposes, in particular also for heating the electrical potential change device. As a result, the reliability can be increased, in particular if the electrical potential-changing device has a battery.

In particular, it may prove to be particularly preferred in the proposed arrangement, if the at least one equipment room device additionally lent the at least partially receiving at least one transformer device and at least one inverter device is used. Such a design makes it possible for the number of technologically available nikraumeinrichtungen can be further reduced and / or the quality of housings (for example, housings for the inverter devices) may be lower. In particular, in the case of a (partial) arrangement of a corresponding device or the corresponding devices within a technology room device, a generally significantly reduced theft protection, vandalism protection, access protection and / or weather protection is sufficient (in comparison to an arrangement "in the field"). In general, it even proves to be more than sufficient if a simple contact protection against accidental contact is provided. Because the "actual" backup or the "actual" weather protection can indeed be provided by the equipment room equipment. Access to the equipment room facility, however, is generally limited to suitably qualified and authorized personnel. Another advantage of the proposed embodiment is that the waste heat from both inverter devices, as well as transformer devices can be used to heat the potential variation device, which may have corresponding (combination) advantages. Contrary to the hitherto prevailing view that the inverter devices are to be arranged as close as possible to the photovoltaic cell modules in order to reduce energy transmission losses, the inventors have surprisingly found that this disadvantage does not usually occur, especially with a corresponding, suitable grouping of the photovoltaic cell modules even possibly an advantage. If, for example, a corresponding number of photovoltaic cell modules are suitably coupled to one another, voltages in the range of typically approximately 1000 V are to be transmitted. Therefore, the ohmic resistance of the corresponding transmission cable usually plays a relatively small role. On the contrary, if only a "simple" inverter device (which does not additionally transform the voltage) is switched between the photovoltaic cell module and the transformer device, then the inventors have discovered, to their own surprise, that the inverter device can rather cause a voltage drop (for example caused by transformer losses). So would an arrangement of an inverter device adjacent to the photovoltaic cell module modules thus, on the contrary, leads to an increase in energy transmission losses. Accordingly, an arrangement of the inverter device (s), the transformer device (s) and the potential variation device (s) as closely as possible to one another can prove to be particularly advantageous.

It is particularly advantageous if the arrangement additionally comprises at least parts of a photovoltaic system, in particular at least one transformer device, at least one inverter device, at least one photovoltaic cell, at least one photovoltaic cell module at least one photovoltaic cell panel and / or at least one preferably movably formed holding device, in particular for at least one photovoltaic cell, for at least one photovoltaic cell module and / or for at least one photovoltaic cell panel. More preferably, the arrangement can also be designed as a photovoltaic power plant. As already mentioned, an unfavorable electrical potential relative to the ground potential, especially in the case of photovoltaic systems, can lead to premature degradation of efficiency, premature degradation, premature power loss, premature wear or even premature failure of the plant or plant components (in particular of the photovoltaic cells yourself). Therefore, the use of the arrangement in this context proves to be particularly advantageous. This applies in particular if at least partially thin-film photovoltaic cells and / or photovoltaic cells contacted on the back side are used as photovoltaic cells. Experiments have shown that just such thin-film photovoltaic cells or photovoltaic cells contacted on the back side can react particularly sensitively to unfavorable electrical potentials or unfavorable electric fields. Under a photovoltaic cell is usually understood a unit that can be made of a so-called wafer (usually by sawing). Typical diameters of photovoltaic cells are therefore in the range of 5 cm, 10 cm, 20 cm or 30 cm. Most photovoltaic cells are not as individual cells, but as so said photovoltaic cell modules distributed, which have a size of, for example, 50 x 50 cm ² and in which a plurality of individual photovoltaic cells are electrically and mechanically connected to each other in a holding frame. As photovoltaic panels are typically understood arrangements of multiple photovoltaic cell modules. Photovoltaic panels can have sizes of several square meters.

It is particularly advantageous if, in the arrangement, the at least one inverter device is designed as a galvanically insulating inverter device and / or as a galvanically non-insulating inverter device and / or as a two-phase alternating current generating inverter device and / or three-phase alternating current generating inverter device and / or multi-phase alternating current generating inverter device. First experiments have shown that, in particular in the aforementioned embodiments, the at least one inverter device can result in particularly great advantages. Thus, it is possible for example with a galvanically insulating inverter device that different areas of the solar cell array can be provided with a different potential. Because of the galvanically insulating inverter device, different areas of the solar cell array are galvanically separated from each other without the need for additional components. It is also possible that the solar cell areas and the current-conducting areas (in particular between the inverter and the transformer) can be set to different potentials. This is usually an advantage, for example, when determining insulation problems. If, on the other hand, galvanically non-insulating inverter devices are used, it is generally possible to manage with a particularly low number of electrical potential-changing devices (possibly also with a single electrical potential-changing device), which can reduce the overall outlay for the system. In particular, this can also reduce any interconnection effort. Two-phase alternating current, three-phase alternating current or multiphase alternating current (in particular with four or more phase sen) may prove to be particularly advantageous depending on the size of the solar cell array. In particular, in the context of alternating current, it is also of particular advantage if an electrical potential change device with a substantially arbitrary potential (that is, not just a grounding possibility) can be provided. Because of a suitable position of the potential an unfavorable potential for the photovoltaic cells can be prevented or largely avoided even with negative half-wave components and the like. Furthermore, it may prove to be advantageous if, in the arrangement, the electrical potential of at least one negative voltage line and / or at least one positive voltage line and / or one AC voltage line and / or at least one neutral line changes (or is fixed). In this way, in particular advantageous electrical potentials for the photovoltaic cells or advantageous electric fields in the photovoltaic cells can be realized, which in particular can have positive effects on the durability of the system. Additionally or alternatively, especially in the proposed development, the risk for operating personnel, passers-by or other persons can also be reduced by static stresses.

It may also be particularly advantageous if, in the arrangement, the size of the potential shift is at least partially and / or at least partially variable, and in particular time-dependent, light intensity-dependent, temperature-dependent, voltage-dependent, current-dependent and / or dependent on the control input of an interface device. In this way, the system can be operated particularly flexible, durable and easy to maintain. In particular, an input can be made via an interface device by manual input and / or by remote control input. In both cases, it usually proves to be advantageous if the electrical potential change device centrally and / or in the vicinity of certain components, in particular transformers and / or inverters. arranged directions. Because such components usually have anyway input options (both by manual input or by telecontrol inputs). In this way it is possible, for example, to shorten or save data transmission lines and if necessary also to avoid data transmission errors. Of course, it is also possible that the interface device can transmit data in both directions. For example, the DC voltage source can measure the applied "correction voltage" and output these measurements via the interface device. If necessary, the measured values can be transmitted further via remote data transmission lines.

Furthermore, it can prove to be advantageous if in the arrangement at least parts of the photovoltaic cells, in particular parts of the photovoltaic cell modules and / or parts of the photovoltaic cell panels (if present) are electrically grouped, such that the individual groups at least partially different current paths for the generated Have current. In this way, a particularly high reliability and / or efficiency of the system can be realized. In particular, it is possible, for example, that the grouping of the photovoltaic cells takes place in such a way that these groups are based on the irradiation intensity (which in turn depends on the position of the sun). With such a grouping, the different solar irradiation, and thus the different generated electrical power, can then be taken into account and / or compensated for, for example, by the inverters or by other measures, so that the overall efficiency of the overall system can possibly increase appreciably.

Furthermore, it may be advantageous if, in the arrangement, at least parts of at least one inverter are arranged adjacent to at least one photovoltaic device. As a result, in particular power line losses can be avoided by a DC transmission at relatively low voltage. Due to the relatively low voltage incidentally, the currents are correspondingly large. Accordingly, it is with the training also possible to be able to save particularly thick (and thus particularly costly) cable. This can significantly reduce the costs of the system. In addition, it should be pointed out that power electronics for inverters are only available up to a certain maximum power or make economic sense. Accordingly, a splitting into a larger number of inverters is often required anyway. If these are each arranged adjacent to a specific group of photovoltaic elements, the efficiency of the system can be increased again or the costs for the system can be reduced even further.

A further preferred embodiment of the arrangement may result if at least one switch device and / or at least one securing device is provided. It is preferred if at least one electrical potential change device is arranged between the at least one switch device and / or the at least one fuse device and at least one electrical device, in particular at least one transformer device and / or at least one inverter device. In particular, if at least one switch device (which can be switched, for example, by operating personnel, maintenance personnel and / or by remote action) is provided, it is possible that parts of the system can be electrically separated from the other parts of the system. As a result, for example, a small portion of a solar power plant can be switched off in order to carry out maintenance work (for example, replacement of solar cells, maintenance of solar cell supports, maintenance of inverters, and the like). Nevertheless, it is possible that the solar power plant as such can still generate electrical energy. In particular, if only a comparatively small proportion of the solar power plant is switched off, the power loss of the solar power plant is possibly barely noticeable. Such a construction is advantageous under the principle of security of supply. The same applies when providing safety devices. Here, when an electrical fault occurs, Only a small proportion of the system The loss of generated electrical energy until repair is then comparatively low. The proposed arrangement of the at least one electrical potential change device relative to the at least one electrical device and the at least one switch device and / or the at least one safety device therefore usually proves to be particularly advantageous, because then usually still functional (not disconnected) parts of the overall system can still be operated with a suitable (suitably set) electrical potential. At the same time a particularly high level of security can be ensured, in particular for maintenance personnel and other persons.

It is particularly preferred if at least one safety shutdown device, in particular a residual current circuitbreaker device, is provided for switching off the electrical potential change device in the system. In this way, the protection for the operating personnel, maintenance personnel or other persons can be increased again. However, it is also conceivable that the safety shutdown device additionally or alternatively also switches off other electrical components of the system (such as, for example, inverters, servo motors and the like).

In the following the invention with the aid of different embodiments and with reference to the accompanying figures will be described in more detail. Show it:

Fig. 1: A first embodiment of a solar power plant in a schematic component representation;

2 shows a second embodiment of a solar power plant in a schematic component representation; 3 shows a third exemplary embodiment of a solar power plant in a schematic component representation;

4 shows an exemplary embodiment of a substation in different schematic views.

In Fig. 1, a possible, first embodiment of a solar power plant 1 is shown in a schematic component view. The solar power plant has a larger number of solar cells 2, which are indicated only schematically in Fig. 1. The solar cells 2 are installed in the form of commercially available solar cell modules. In the presently illustrated embodiment, a plurality of solar cell modules are mechanically and electrically combined to solar cell panels. The solar cell panels, in turn, are typically mounted with a suitable slope on handrails (which may also be movably mounted).

The DC voltage generated by the solar cells 2 (positive pole in Fig. 1 above, negative pole shown in Fig. 1 below) is fed via an appropriately dimensioned DC cable 3 an inverter 4. The inverter 4 generates from the DC voltage 5 an AC voltage 6, in the presently illustrated embodiment of the solar power plant 1 a Dreiphasenwech- selspannung 6 with separate neutral conductor 7. The inverter 4 is formed in the illustrated embodiment as a transformer-free inverter 4, which consequently acts galvanically non-insulating ,

According to the present exemplary embodiment, solar cells 2 and inverters 4 are arranged "in the field." Preferably, the inverter 4 is arranged in the immediate vicinity of the solar cells 2 so as to transfer the losses due to the DC voltage transmission 5 (which takes place with a comparatively low voltage) For example, it is possible for the inverter 4 to be mounted on a support bracket for solar cell panels or on the back side of solar cell panels Especially possible because thanks to the now available power electronics, the weight of modern inverter 4 has greatly decreased. The transmission of the three-phase alternating current 6 in the direction of the substation 8 (schematically illustrated by a dashed line in FIG. 1), on the other hand, takes place at an increased voltage in the form of three-phase alternating current 6. Substation 8 and solar cells 2 are typically several tens of meters to several hundred meters apart arranged.

The substation 8 may, for example, be a typical transformer house, which in particular may be designed according to a typical appearance for the respective country. A possible embodiment for such a substation 8 can be found in Fig. 4. Typically, substations 8 are weatherproof (ie rainproof and the like) executed by their structural design. Furthermore, substations 8 are secured against unauthorized entry, for example, by mechanical locks or electronic access mechanisms. As usual, in the substation 8 shown in FIG. 1, a transformer 9 is optionally arranged, which transforms the three-phase alternating current 6 led via a cable 10 to a generally significantly higher voltage and outputs it via a high-voltage output 11. For example, voltages of several or more than 10 kV can be present here. The transformer 9 also acts galvanically insulating. High voltage output 11 and AC cable 10 (as well as the solar cell 2 via the inverter 4) are thus galvanically isolated from each other.

After it has been shown that with the use of thin-film solar cells, a rapid deterioration of the efficiency of the solar cell 2 may occur when these (partially) compared to the surrounding ground potential have a lower voltage, in the present case a DC voltage source 12 (the electrical potential change device) is provided which places the neutral conductor 7 of the three-phase AC cable 10 at a defined potential, which is increased from the ground potential. The height the potential of the neutral conductor 7 is chosen so that each individual phase of the three-phase alternating current 6 is maintained at any time above the ground potential, but at least at ground potential. The voltage of the DC voltage source 12 is further selected so that both poles of the DC voltage 5 (in particular, the negative pole) are above the ground potential, but at least at ground potential. Since the inverter 4 in Fig. 1, as already mentioned, is of the non-galvanic insulating type, a suitable potential shift for both the solar cell 2, as well as for the AC cable 10 (including inverter 4), with a single DC voltage source 12th be varied.

If instead of thin-film solar cells back contacted solar cells used, it is necessary that the electrical potentials of the back contacted solar cells as possible at any time below ground potential are (in particular, the positive pole of the rear contacted solar cells) to prevent a rapid deterioration of the efficiency ,

Preferably, the DC voltage source 12 is designed so that it draws its E nergy requirements on the electrical energy generated by the solar power plant 1. However, in particular for the bridging of night phases and the like, (additional) batteries can be provided. Preferably, the level of the voltage of the DC voltage source 12 can also be changed variably and, for example, by a timer (night service), by user intervention (for example by a control panel) or by remote control (for example data transmission networks).

As in the presently illustrated embodiment, the DC voltage source 12 is located in an area separated by an intermediate wall 13 from the space provided for the transformer 9 space within the substation 8. The DC voltage source 12 can therefore be provided with a much less expensive housing (usually no weather protection required), as the weather protection is provided by the building of substation 8. In addition, since the substation 8 is secured against unauthorized entry, the DC voltage source 12 is also protected against unauthorized manipulation, vandalism or theft. In addition, the waste heat of the transformer 9 can increase the operational reliability of the DC voltage source (in particular its battery), especially in winter. It should also be noted that transformers 9 (or electrical contactors within substation 8) of the present state of the art often need to be switched (both by manual access and by remote control). If a switch by manual access, so the operator of the system not only the transformer 9, but also the DC voltage source 12 with switch. This can save costs for operating personnel. Also in the case of telecontrol, the situation can be particularly simple, since the provided for the circuit of the transformer 9 control lines can also be used for the control of the DC voltage source 12. Due to the spatial proximity of DC voltage source 12 and transformer 9 can be dispensed with the laying of longer data lines, which in particular cost-effective (or cost-reducing) can affect. Also, at least some components of the remote data transmission device can be arranged within the substation 8, so that they are also in particular weatherproof, theft-proof and vandalism-proof arranged. 2, a second embodiment of a solar power plant 14 is shown. The second embodiment of a solar power plant 14 is similar to that shown in Fig. 1, the first embodiment of a solar power plant 1. However, in the presently illustrated, the second embodiment of a solar power plant 14, a galvanically insulating inverter 15 is provided. Because of this galvanic isolation, not only is the high voltage output 11 galvanically isolated from the other components (ie, solar cells 2 and three-phase AC cables 10), but AC cables 10 and solar cells 2 are also galvanically isolated from each other. Accordingly, now two different potentials must be defined with respect to the ground potential, namely the potential of the three-phase alternating current 6, as well as the potential of the DC voltage 5 in the solar cell. 2

In order to determine the potential of the three-phase alternating current 6, (in analogy to the exemplary embodiment shown in FIG. 1), a first direct voltage source 16 is used, which defines the potential of the neutral conductor 7 with respect to the ground potential. As a result, the potential of the other phases (or lines) of the three-phase alternating voltage 6 is also indirectly determined. On the now galvanically independent solar cell side of the inverter 15, a second DC voltage source 17, which may be formed independently of the first DC voltage source 16, is provided. The second DC voltage source 17 controls the electrical potential of the DC voltage 5 via an electrical connection to the DC cable 3, which derives the current of the solar cell 2. In particular, it is possible for the electrical potential of the positive or negative voltage output of the solar cells 2 to be determined, as a result of which the potential of the positive or negative output of the solar cells 2 is also determined indirectly.

The first DC voltage source 16 and the second DC voltage source 17 may preferably be controlled independently of each other. From the construction, however, the two DC voltage sources 16, 17 may be constructed substantially identical. In addition, the structure can be similar to the construction of the DC voltage source 12 shown in FIG.

Also in the presently illustrated embodiment, the two DC voltage sources 16, 17 are arranged within the substation 8 in a separated by an intermediate wall 13 from the space of the transformer 9 subarea. The advantages already described arise analogously. A little problematic in the illustrated arrangement, if necessary, that the copper cable 3 between solar cell 2 and inverter 15 now a have greater length. Therefore, it is also possible that instead of the left outer wall 18 shown in FIG. 2, the alternative outer wall 19 of the substation 8 is provided. In this case, the inverter 15 and the second power source 17 are "outdoors." Specifically, it is possible for the second power source 17 to be formed together with the inverter 15 in a housing.

Initial tests have shown, however, that an adjacent arrangement of transformer 9, inverter 15 and voltage source 16 and / or voltage source 17 within the substation 8 may even have advantages in terms of energy losses occurring. Although then the copper cable 3 between the solar cell 2 and inverter 15 is comparatively long (the AC cable 10 is usually significantly shorter accordingly). The inventors have found, however, that when using an inverter 15, which performs no (additional) voltage transformation (ie in particular when using galvanically non-insulating inverters 15), a certain converter loss occurs, so that the voltage before the inverter 15 (ie in the Copper cable 3) is higher than after the inverter 15 (ie in the AC cable 10). Accordingly, a "long" copper cable 3 (with a correspondingly short AC cable 10) may even prove to be particularly advantageous in terms of inevitable losses. Of course, this advantage may arise independently of whether only a single DC voltage source 12 (similar to the exemplary embodiment shown in FIG. 1) or a plurality of DC voltage sources 16, 17, 17 '...

For the sake of completeness, it is pointed out that the second DC voltage source 17 can also be arranged at an alternative location 17 ', where the DC voltage source 17' determines the potential of the plus side of the solar cells 2 (and thus indirectly also the potential of the minus side of the solar cells 2). , In Fig. 3 is a variation of the embodiment of a solar power plant 14 shown in Fig. 2, a third embodiment of a solar power plant 20 is shown schematically. The third embodiment of a solar power plant 20 is very similar to the solar power plant 14 shown in FIG.

However, the solar power plant 20 shown here has a larger number of solar cells 2, 2 '. In order not to have to enlarge the inverter 15 excessively, a second inverter 15 'is provided which converts the direct current 5' supplied by the second solar cell unit 2 'into a three-phase alternating current 6'. The two inverters 15, 15- are connected in parallel to each other, so that the current strengths of the two three-phase alternating currents 6, 6 'add. Overall, thus at the high voltage output 11 of the solar power plant 20, a larger power available. For this purpose, the two inverters 15, 15 'are of course designed such that they take into account the phase position of the respective other inverter 15, 15'.

Since the two inverters 15, 15 'are designed as galvanically insulating inverters 15, 15', the potentials of the two direct voltages 5, 5 'and of the three-phase alternating current 6, 6' can each be determined independently of one another. To establish serve in Fig. 3 to be recognized DC voltage sources 16, 17, 17 '. Of course, it is also possible (in particular with a higher output power of the solar power plant 20) to provide a larger number of inverters 15, 15 '(including the "associated" components).

Finally, FIG. 4 shows a typical design for a substation 8 from different directions. Fig. 4b shows the substation 8 from the front, wherein the (lockable) door 21 (preferably provided with two door wings) is shown. FIG. 4 d shows how the rear side can also be provided with a door 21. Figures 4c and 4e show the side walls of the substation 8, wherein in Fig. 4e in the region of the side wall additionally a lamellar ventilation grille 22 is provided for cooling purposes. The substation 8 is, as can be seen Fig. 4b - 4e partially sunk in the bottom 23.

Furthermore, in Fig. 3, first and second electrical contactors 25, 26, 26 'can be seen, which are presently designed as 4-way contactors 25, 26, 26'. With the first electric contactor 25, it is possible to electrically disconnect the transformer 9 from the AC power cable 10. The first DC voltage source 16 is arranged on the transformer side in front of the first electrical contactor 25. If the first electrical contactor 25 is opened, the AC cable 10 is thus simultaneously disconnected from the DC electrical voltage of the first DC voltage source 16. This is particularly advantageous in terms of job security.

The second electric contactors 26, 26 'are respectively provided in the vicinity of the inverters 15, 15' between the inverters 15, 15 'and the AC power cable 10 (AC bus). In this way, it is possible to separate individual inverters 15, 15 'together with the plant components located behind them (in particular DC cables 3, 3' and solar cells 2, 2 ') from the "main plant part" of the solar power plant 20. This makes it possible in a simple manner, the corresponding part of the system (for example, the respective inverter 15, 15 ') to maintain or replace without the entire solar power plant 20 must be turned off. This is particularly economical, and also particularly advantageous under the aspect of security of supply. It is also possible, by the way, that the control signal for controlling the corresponding second electrical contactor 26, 26 'at the same time switches off the second DC voltage source 17, 17' corresponding thereto. For the sake of completeness, it should be pointed out that it is possible in a variation of the solar power plant 20 shown in FIG. 3, instead of galvanically insulating inverters 15, 15 ', galvanically non-separating Inverter to use. In such a construction, basically only the use of a single DC voltage source 16, 17, 17 'for the entire solar power plant 20 is necessary. In such a case, the arrangement of the DC voltage source at the location of the first DC voltage source 16 shown in FIG. 3 is particularly advantageous. Here, by switching off a single, namely the first electrical contactor 25, the entire solar power plant 20 can be switched DC-free. Otherwise, it would possibly be necessary to have to switch a larger number or all of the second electrical contactors 26, 26 'until the DC-voltage-free state is reached. It should be noted that the solar power plant 20 anyway no longer produces electrical energy when switching off the first electric contactor 25. Switching off only individual plant parts 2, 2 ', 3, 3', 15, 15 'therefore makes no sense. In Fig. 4a, the substation 8 is shown in a schematic cross section from above. To recognize the located on the front and the back of the substation 8 doors 21. In a sub-area 24 of the substation 8 of the transformer 9 is arranged. Through an intermediate wall 13 results in a subspace 24 of the substation 8, in which in particular the DC voltage source or the DC voltage sources 16, 17, 17 ', 12 and optionally other components can be arranged.

LIST OF REFERENCE NUMBERS

1. Solar power plant

2. Solar cells

3. DC cable

4. Inverter (not electrically isolated)

5. DC voltage

6. Three-phase AC voltage

7. Neutral

8. Substation

9. Transformer

10. AC power cable

11. High voltage output

12. DC voltage source

13. intermediate wall

14th solar power plant

15. Inverter (galvanic insulating)

16. First DC voltage source

17. Second DC voltage source

18. Left outer wall

19. Alternative exterior wall

20th solar power plant

21st door

22. Ventilation grille

23. floor

24th compartment

25th first electrical contactor

26. second electric contactor

Claims

Patent claims

1. Arrangement (1, 14, 20), comprising at least one electric potential changing device (12, 16, 17, 17 ') for changing the electrical see potential of at least one electrical device (2, 2', 4, 15,

15 ') relative to ground potential, characterized by at least one equipment room device, wherein the electrical potential change device (12, 16, 17, 17') is at least partially disposed in the operating state in the at least one equipment room device (8).

2. Arrangement (1, 14, 20) according to claim 1, characterized in that the at least one equipment room device (8) at least partially as a building device (8) and / or as a closable (21) device (8) and / or at a central Location is formed.

3. Arrangement (1, 14, 20) according to claim 1 or 2, characterized in that the at least one equipment room device (8) of at least partially receiving further components, in particular of transformer devices (9) and / or of inverter devices (4 , 15, 15 ') serves.

4. Arrangement (1, 14, 20) according to any one of the preceding claims, characterized in that the at least one equipment room device (8) additionally at least partially receiving at least one transformer device (9) and at least one inverter device (4, 15, 15 ') is used.

5. Arrangement (1, 14, 20) according to one of the preceding claims, characterized by at least parts of a photovoltaic system (1, 14, 20), in particular at least one transformer device (9), at least one inverter device (4, 15, 15 ') , at least one photovoltaic cell (2, 2 '), at least one photovoltaic cell module, at least a photovoltaic cell panel (2, 2 ') and / or at least one preferably movably formed holding device, in particular for at least one photovoltaic cell, for at least one photovoltaic cell module and / or for at least one photovoltaic cell panel (2, 2'), preferably characterized in that the arrangement as Photovoltaic power plant (1, 14, 20) is formed.

6. Arrangement (1, 14, 20) according to one of the preceding claims, in particular according to claim 5, characterized in that the at least one inverter device (4, 15, 15 ') as a galvanically insulating inverter device (4) and / or as a galvanically non-insulating Inverter means (15, 15 ') and / or as a two-phase alternating current generating inverter means and / or three-phase alternating current generating inverter means (4, 15, 15') and / or formed as a multi-phase alternating current generating inverter means.

7. Arrangement (1, 14, 20) according to one of the preceding claims, characterized in that the electrical potential of at least one negative voltage line (3) and / or at least one positive voltage line (3) and / or at least one AC voltage line (10) and / or at least one neutral line (7) is changed.

8. Arrangement (1, 14, 20) according to one of the preceding claims, characterized in that at least partially and / or at least partially the size of the potential shift is variable, and in particular time-dependent, light intensity-dependent, temperature-dependent, voltage-dependent, current-dependent and / or in dependence from the control input via an interface device.

9. Arrangement (1, 14, 20) according to one of the preceding claims, in particular according to one of claims 4 to 8, characterized in that at least parts of the photovoltaic cells (2, 2 '), in particular parts of the photovoltaic cell modules and / or parts of the Photovoltaikzellenpa - Neele (2, 2 ') are electrically grouped, such that the individual groups have at least partially different current paths (6, 6') for the generated current.

10. Arrangement (1, 14, 20) according to one of the preceding claims, in particular according to claim 4 to 9, characterized in that at least parts of at least one inverter (4, 15, 15 ') adjacent to at least one photovoltaic device (2, 2 ') are arranged.

11. Arrangement (1, 14, 20) according to one of the preceding claims, characterized by at least one switching device (25, 26, 26 ') and / or at least one securing device, wherein preferably at least one electrical potential changing device (12, 16, 17 , 17 ') between the at least one switching device (25, 26, 26') and / or the at least one securing device and at least one electrical device (4, 9, 15, 15 '), in particular at least one transformer device (9). and / or at least one inverter device (4, 15, 15 ') is arranged.