JP2012089787A - Photovoltaic power generation system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the following problem: a conventional photovoltaic power generation system has an uncomfortable appearance because of separate installation of a booster from a junction box and worse safety due to an increase in probability of erroneous construction.SOLUTION: To solve the above problem, the photovoltaic power generation system of the invention includes a plurality of strings connected with a plurality of solar cell modules and a junction box for bounding DC voltages generated for each of the strings. The junction box is structured to store a booster for boosting a part or all of the strings.

Description

  The present invention relates to a solar power generation system that generates power using sunlight, and more particularly to a connection box for orderly connecting a plurality of solar cell modules, a device connected to a power conditioner, and a technique for easily connecting cables.

The solar power generation system generates direct-current power when the solar cell module is irradiated with sunlight, is converted into alternating-current power by a power conditioner (hereinafter referred to as “PCS”), and supplies power to the power system. .

In a general photovoltaic power generation system, solar energy is converted into DC power by a solar cell module (string), and then each string voltage is boosted by a booster so that the voltage values of other strings are matched. Further, the combined DC power is converted into AC power by PCS.

By the way, although the solar cell module used for many photovoltaic power generation systems is arrange | positioned in the unit of the string 1 which connects and connects several solar cell modules in series, each module receives sunlight on the roof surface. It needs to be arranged so that it can.

For example, the number of solar cell modules constituting each string is often different, such as 4 series 2 parallel installations on the south facing roof and 3 series 1 parallel installations on the east and west facing roofs.

In this case, the voltage obtained from the south facing roof is different from the voltage obtained from the east facing and the west facing. Here, the reason why the south-facing roofs are arranged in parallel is to prevent the roof from being out of the rated voltage range (for example, 120 V to 370 V) of the PCS.

The connection box is connected so that the voltage from each string is concentrated on the terminal block, but the aggregated voltage is a low voltage obtained from the east and west facing roofs, and is obtained from the south facing roof. Cannot be used effectively. (For example, Patent Document 1)

JP 2004-55603 A (FIG. 1)

For this reason, in order to supply power efficiently, a booster is provided so that a low voltage system can be adjusted to a high voltage value.

However, providing a booster separately is not preferable in appearance.

In addition, since the number of man-hours for separate installation increases, there are problems that the system cost increases due to an increase in construction costs, and the probability of construction mistakes increases and the safety decreases.

In particular, construction mistakes in connecting DC cables with crimping rods or crimping terminals attached to the input part from the solar cell to the booster and the output part from the booster to the junction box can cause smoke and fire. There was a problem with safety.

In order to achieve the above object, in the photovoltaic power generation system of the present invention, a photovoltaic power generation system having a plurality of strings in which a plurality of solar cell modules are connected and a connection box for bundling a DC voltage generated for each string. In the present invention, the junction box is configured to accommodate a booster that boosts part or all of the string.

In the present invention, since the booster device is provided in the junction box or the PCS, the appearance can be improved without reducing the amount of power generation.

In addition, by using a member that has a booster device, it is not necessary to install a booster device separately, so that installation man-hours are not increased, system costs are reduced, and safety is improved by reducing the probability of construction errors. I can do it.

It is the figure which showed the whole image in the solar energy power generation system by this invention. It is the figure which showed Example 1 in the solar energy power generation system of this invention. It is the figure which showed Example 2 in the solar energy power generation system of this invention. It is the figure which showed Example 3 in the solar energy power generation system of this invention. It is the figure which showed other embodiment in the solar energy power generation system of this invention. It is the figure which showed other embodiment in the solar energy power generation system of this invention. It is the figure which showed other embodiment in the solar energy power generation system of this invention. It is the figure which showed Example 4 in the solar energy power generation system of this invention.

  Examples of the present invention will be described below.

  A first embodiment of the photovoltaic power generation system according to the present invention will be described with reference to FIGS. 1 and 2.

  FIG. 1 is a diagram when a photovoltaic power generation system is used for a house.

  Reference numeral 1 denotes an electric power system that supplies commercial AC power to each home.

2 indicates a house, 3 indicates a south roof, 4 indicates a west roof, and 5 indicates an east roof 5.

  6 is a solar cell module, and a plurality of solar cell modules are arranged in a range that can be installed on each roof surface.

  The solar cell modules 6 are connected in series by cables 10, 11, and 12, respectively, and constitute strings 7, 8, and 9.

In order to combine the systems of the plurality of solar cell modules 6 into one, the strings 7 to 9 are connected to the inside of the connection box 13 by DC cables 20 to 22 and connected to the PCS 14 and further to the distribution board 15. .

  A grid breaker 16 is provided from the grid 1 to the distribution board 15 to provide a function to shut off when an abnormal current flows due to leakage or the like, and between the grid breaker 16 and the distribution board 15 is provided. A power meter 17 is provided for detecting so-called electric power sales amount and electric power purchase amount of electric power from the solar cell module.

  The distribution board 15 is connected via a cable 18 to a household load 19 (home appliance such as an air conditioner).

Arranged on each roof surface via a frame (not shown), the south roof 3 has 4 series 2 parallel strings 7, and the west roof 4 and east roof 5 have 3 series 1 parallel strings. 8 and 9 are arranged.

  One end of each of the strings 7 to 9 has DC cables 20 to 22, and an anode terminal portion and a cathode terminal portion (not shown) as connection portions of the individual DC cables 20 to 22 are provided in the connection box 13, respectively. Connected to a breaker described later. The breaker is connected to one of the anode terminal 24 and the cathode terminal 25 of the terminal block 23 via a cable.

  The other anode terminal 26 and cathode terminal 27 of the terminal block 23 of the connection box 13 are connected to a PCS 14 that converts direct current into alternating current via cables 28 and 29, and further connected to a distribution board 15.

  The connection box 13, the PCS 14, and the distribution board 15 are attached to the wall surface of the house 3.

  Next, the configuration in the junction box will be described in detail with reference to FIG.

  FIG. 2 is a view showing the inside of the connection box with the front cover of the connection box removed.

  In the connection box 13, six breakers 30, 31, 32, 33, 34 and 35 for connecting the DC cables 20 to 22 from the strings 7 to 9 of the solar cell module 6 are arranged in a horizontal row. .

One of the breakers 30 to 35 is provided with anode terminals 30a to 35a and cathode terminals 30b to 35b, respectively. Also, cables 30c to 35c and 30d to 35d are connected to these terminals, respectively, and the other ends of the cables 30c to 35c and 30d to 35d correspond to the anode terminal 24 and the cathode terminal 25 of the terminal block 23, respectively. Connected.

In the drawing, only the breakers 30 and 31 are shown as cables. However, the breakers 32 to 35 are also connected to the respective terminals of the terminal block 23 via the cables in the same manner as the other breakers.

In addition, each of the breakers 30 to 35 is provided with switches 30e to 35e for switching on and off.

The switches 30e to 35e are turned on when they are raised upward and turned off when they are lowered downward.

  In the present embodiment, among the six breakers 30 to 35, the breakers 30 and 31 are not connected to the strings, and the switches of the breakers 30 and 31 are turned off.

With respect to the breakers 32 and 33, since the four series strings 7 are connected, the DC cables 20 and 20 are not connected to the anode terminals 33a and 34a and the cathode terminals 33b and 34b of the breakers 34 and 35, respectively. Direct connection (without going through the device). The switch 32e and the switch 33e are turned on.

For the breakers 34 and 35, the anode terminals 34a and 35a and the cathode terminal 34b are connected via the cables 36e, 36f, 37e and 37 connected to the anode terminals 36c and 37c and the cathode terminals 36d and 37d of the boosters 36 and 37, respectively. 35b. The switches 34e and 35e are also turned on.

  The west roof string 8 includes DC cables 21 a and 21 b at one end thereof, and is connected to the anode terminal 36 a and the cathode terminal 36 b of the booster 36.

Similarly, the string 9 on the east side roof has DC cables 22a and 22b at one end thereof, and is connected to the anode terminal 37a and the cathode terminal 37b of the booster 37.

As the output, the string 7 of the south side roof 3 is about 200V (about 50V per module) because it is 4 series and 2 parallel.

  Since the string on the west roof is 3 series and 1 parallel, the output is about 150V (about 50V per module).

  Moreover, since the string of the east side roof is also 3 series and 1 parallel like the west side roof, the output is about 150V (one module is about 50V).

Thereby, the electric power generated by each of the strings 7 to 9 is guided from the DC cables 20 to 22 to the terminal block 23 via the breakers 32 to 35. At this time, the string 8 on the west roof and the string 9 on the east roof are boosted by the booster 36 and the booster 37 in the same manner as the voltage of the string 7.

  When the output from the string 7 on the south side roof (about 200V) is connected in parallel to the terminal block 23 from the string 8 on the west side roof and the string 9 on the east side roof via the breakers 34 and 35, the voltage of the terminal block 23 is Since it becomes about 150V equivalent to the east side roof and the west side roof, the power generation by the string 7 of the south side roof 3 cannot be effectively utilized. Therefore, the voltage from the string 8 on the west roof 4 and the string 9 on the east roof 5 is boosted to match the voltage on the strings 7 and 7 on the south roof 3.

  The voltage of the string 8 and the string 9 is boosted to around 200 V by the booster 36 and the booster 37.

  Further, the booster 36 and the booster 37 are of a size that can be accommodated in the junction box 13, and are accommodated in the junction box 13 as shown in FIG. 2, for example.

  DC power from each of the strings 32, 33, 34, 35 is directly led to the distribution board 15 from the strings 7, 7 of the south side roof 3, and from the strings 8, 9 of the west side roof 4 and the east side roof 5, The voltage is boosted by boosters 34 and 35 and led from the terminal block 23 to the distribution board 15 via the PCS 14.

  In the case of this embodiment, six breakers 30 to 35 are provided. In order to boost the voltage from the strings 8 and 9 that need to be boosted, boosters 36 and 37 are attached to the strings 7 and 9, respectively. It is configured to obtain a more optimal power generation capacity by equalizing the voltage.

  With the above configuration, the DC power generated by each solar cell module is supplied to the PCS from the terminal block via the breaker or the booster and the breaker.

  In PCS, direct current is converted into alternating current, and power is supplied from a distribution board to a load such as a home appliance, or in the case of surplus power, it is sent to the system via an AC breaker. The power sent to the system can be measured by a power meter.

  As described above, in this embodiment, since the booster device is arranged in the junction box, it is possible to improve the appearance of the photovoltaic power generation system without reducing the power generation amount.

FIG. 3 is a diagram illustrating the junction box 13 according to the second embodiment.

The same reference numerals are given to configurations common to the first embodiment, and details of different configurations will be described.

In the present embodiment, a portion where the string DC cable 20 or the boosting devices 36 and 37 provided in the breakers 30 to 35 is connected is a plug-in connector.

Specifically, plug-in connectors 30f to 35f are provided at the anode portion and plug-in connectors 30g to 35g are provided at the cathode portion so as to protrude below the breakers 30 to 35.

Corresponding to the anode portions 30f to 35f and the cathode portions 30g to 35g, plug-in connectors 36h, 36i, 37h, and 37i are provided on the anode portion and the cathode portion of the boosters 36 and 37, respectively.

The booster device 36 is provided with plug-in connectors 36f and 36g for connecting the DC cable 21, and the booster device 37 is provided with plug-in connectors 37f and 37g for connecting the DC cable 22.

With the above configuration, it is possible to improve the appearance of the photovoltaic power generation system without reducing the amount of power generation, and to reduce the system cost with few construction errors.

FIG. 4 is a diagram illustrating a junction box according to the third embodiment.

The same reference numerals are given to configurations common to the first embodiment, and details of different configurations will be described.

In the present embodiment, the description is made on the assumption that the string DC cable 20 or the booster devices 36 and 37 provided in the breakers 30 to 35 are plug-in connectors.

Specifically, plug-in connectors 30f to 35f are provided at the anode portion and plug-in connectors 30g to 35g are provided at the cathode portion so as to protrude below the breakers 30 to 35.

Corresponding to the anode portions 30f to 35f and the cathode portions 30g to 35g, plug-in connectors 36h, 36i, 37h, and 37i are provided on the anode portion and the cathode portion of the boosters 36 and 37, respectively.

The booster device 36 is provided with plug-in connectors 36f and 36g for connecting the DC cable 21, and the booster device 37 is provided with plug-in connectors 37f and 37g for connecting the DC cable 22.

Further, the booster 36 and the booster 37 are provided with LEDs 36j and 37j as connection confirmation means, the plug-in terminals necessary for the anode and the cathode of the DC cable 21 of the string 7, and the plug-in connector of the booster 36. If the connection to 36f, 36g, 37f, 37g and the connection of the booster devices 36, 37 to the plug-in connectors 36h, 36i, 37h, 37i are securely performed, the power is supplied and light is emitted. By adopting the above configuration, the appearance of the photovoltaic power generation system can be improved without reducing the amount of power generation, the construction cost can be reduced, the system cost can be reduced, and erroneous connection can be prevented.

In addition, to prevent incorrect connection, misconnection can be achieved by connecting the terminals to each terminal in two stages, or by connecting them securely by attaching a fixed object (not shown) to the plug-in connector. Prevention becomes possible.

Moreover, as shown in FIG. 5, you may make it provide the display apparatuses 30k-35k in each of the breakers 30-35. In the display devices 30k to 35k, by monitoring measured values such as a voltage value, a current value, a power value, and a temperature, a failure analysis can be performed and a system status can be managed.

In addition, as shown in FIG. 6, display devices 36 k and 37 k may be provided in the boosting devices 36 and 37, respectively. In the display devices 36k and 37k, by monitoring measured values such as a voltage value, a current value, a power value, and a temperature, a failure analysis can be performed and a system status can be managed.

Further, as shown in FIG. 7, the breakers 30 to 35 may be provided with communication devices 30n to 35n to have a communication function. By using such a breaker, it is possible to analyze a failure by communicating measured values such as a voltage value, a current value, a power value, and a temperature with a communication function, and to manage the system status at a remote place.

FIG. 8 is a diagram according to a fourth embodiment of the present invention.

In this embodiment, the boosters 36 and 37 are provided in the PCS 38.

  In this embodiment, since the booster devices 36 and 37 are arranged in the PCS 38, it is possible to improve the appearance of the solar power generation system without reducing the amount of power generation. The MPPT (Max Power Tracking Point) function may be provided or the MPPT function may be further provided in the booster.

In each of the above-described embodiments, an example in which two boosting devices are attached has been described. However, the present invention is not limited to this.

DESCRIPTION OF SYMBOLS 1 Electric power system 2 House 3, 4, 5 Roof 6, Solar cell module 7, 8, 9 String 10, 11, 12 Cable 13 Connection box 14 Power conditioner system (PCS)
15 Distribution board 16 Interconnection breaker 17 Power meter 18 Cable 19 Load 20, 21, 22 DC cable 23 Terminal block 28, 29 Cable 30, 31, 32, 33, 34, 35 Breaker 36, 37 Booster 38 Power condition N System (PCS)

Claims (7)

In a photovoltaic power generation system including a plurality of strings each having a plurality of solar cell modules connected and having a connection box for bundling a DC voltage generated for each of the strings, the connection box boosts a part or all of the strings. A photovoltaic power generation system configured to be capable of storing a boosting device to be stored. A solar cell comprising a plurality of strings in which a plurality of solar cell modules are connected, a connection box for bundling a DC voltage generated for each string, and a power conditioner system for converting the connection box into an AC voltage via a DC voltage In the photovoltaic power generation system, the power conditioner system is configured to be capable of storing a boosting device that boosts a part or all of the string. The said connection box or a power conditioner system is equipped with the breaker which can be connected for every said string, It was set as the structure which connects this breaker and the said string with a plug-in connector. Solar power system. 4. The solar power generation system according to claim 1, wherein the booster device includes a maximum power point tracking unit. The solar power generation system according to claim 1, wherein the booster device includes connection confirmation means for confirming whether or not the connection is present. The solar power generation system according to claim 4, wherein the breaker or the booster device includes a monitor that displays a voltage or the like. The solar power generation system according to claim 3, wherein the breaker or the booster includes a communication unit.

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