JP2014107370A - Power transmission line for green power system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power transmission line for a green power system, the power transmission line being able to restrict an increase of the size of an input apparatus, such as a connection box, when the end part of a plurality of cables connected to the power generation means of a solar battery or the like are collected.SOLUTION: A power transmission line for a green power system comprises: power generation means (array 100) for outputting DC power derived from natural energy; power conversion means (power conditioner 400) for converting the DC power to AC power; and a power transmission path between a plurality of power generation means and power conversion means. Further, the power transmission line is provided with output equipment, cables, compaction terminal fitting, and input equipment. The output equipment (array 100) is a plurality of apparatuses included in the power transmission path. The cable is connected to each of output apparatuses. The compaction terminal fitting collects cable terminals into one terminal. The input equipment (connection box 200) is an apparatus to which the compaction terminal fitting is attached. The compaction terminal fitting has a compression part that compresses the conductors of the plurality of cables all at once, and a connection part fixed to the input apparatus integrally with the compression part.

Description

  The present invention relates to a power transmission line suitable for collecting and transmitting power between a plurality of power generation means that output direct-current power derived from natural energy, such as solar cells, and conversion equipment such as a power conditioner.

  Green power utilization technology that uses natural energy such as solar energy, wind power, tidal power, and geothermal heat has attracted attention. In particular, solar cells are used as power generation facilities having megawatt class output.

  Generally, in such a power generation facility, a solar cell is used as an array by connecting a plurality of solar cell modules in series to form a string, and connecting the plurality of strings in parallel. The electric power output from each of the plurality of arrays is collected in a connection box through a cable, and further introduced from the connection box into the power conditioner through a cable. The electric power introduced into the power conditioner is converted from direct current to predetermined alternating current and supplied to the electric power system (refer to Patent Document 1 as a similar technique).

JP 2012-199393

  In such a photovoltaic power generation system, a more simplified configuration is desired as a configuration for collecting power from a plurality of arrays. For example, when power is collected from each array to the connection box, terminal fittings are attached to each of the cable terminals drawn from each of the plurality of arrays, and the plurality of terminal fittings are connected to the terminal block of one connection box. Therefore, a space for connecting a plurality of terminal fittings is required for the terminal block of the connection box, resulting in an increase in the size of the connection box.

  The present invention has been made in view of the above circumstances, and one of its purposes is to increase the size of input devices such as connection boxes when assembling cable terminals connected to output devices such as a plurality of arrays. It is to provide a transmission line of a green power system that can suppress the above.

  The power transmission line of the green power system according to the present invention includes a power generation unit that outputs DC power derived from natural energy, a power conversion unit that converts the DC power into AC power, and a plurality of power generation units and a power conversion unit. The power transmission path is provided. Furthermore, the power transmission line of the green power system includes an output device, a cable, an aggregation terminal fitting, and an input device. The output device is a plurality of devices included in the power transmission path. A cable connects to each of the output devices. Aggregate terminal fittings gather the ends of each cable into one terminal. The input device is a device to which the aggregate terminal fitting is attached. The aggregate terminal fitting includes a compression unit that collectively compresses the conductors of the plurality of cables, and a connection unit that is integrated with the compression unit and fixed to the input device.

  According to this configuration, since the conductors of a plurality of cables can be gathered in the aggregate terminal fitting, it is only necessary to connect a smaller number of aggregate terminal fittings than the number of cables to the input device. Therefore, the number of terminal fittings can be reduced as compared with a case where terminal fittings are attached to each of the conductors of individual cables and the plurality of terminal fittings are connected to an input device. With the decrease in the number of terminal fittings, it is not necessary to increase the size of the connecting portion of the terminal fitting in the input device, and the input device itself can be prevented from being enlarged.

In the power transmission line of the green power system according to the present invention, typical examples of the output device and the input device include the following combinations.
(A) The output device is a power generation means. The input device is a connection box in which DC power from the power generation means is input. (B) The output device is a connection box in which DC power from the power generation means is input. The input device is power conversion means (C). The output device has a junction box to which DC power from the power generation means is input. The input device has a junction box arranged between the connection box and the power conversion means. In case
Collective box in which output device is arranged between junction box and power conversion means Input device is power conversion means These combinations (A) to (D) may be used alone or in combination. You may do it.

  According to this configuration, when the outputs of a plurality of power generation means, connection boxes, or collection boxes are aggregated and connected to the connection box, collection box, or power conversion means, the individual terminal of the cable can be obtained by using the aggregation terminal fitting. The number of terminal fittings can be reduced as compared with the case where terminal fittings are used for. Accordingly, the connection location of the terminal fitting in the input device does not increase in size.

  The power transmission line of the green power system according to the present invention includes a form in which the power generation means is a solar cell.

  According to this configuration, in a power generation system using a solar cell, when the DC power output from the solar cell is collectively input to a power conversion means such as a power conditioner, terminal fittings are used for individual cables. Compared to the case, the number of terminal fittings can be reduced.

  When the outputs from the plurality of power generation means that output DC power are collected and input to the power conversion means, the number of terminals used in the transmission line between the power generation means and the power conversion means can be reduced. In connection with it, the enlargement of the connection object apparatus of a terminal can be suppressed.

It is a schematic block diagram of the solar energy power generation system containing the power transmission line which concerns on Embodiment 1 of this invention. In the system shown in FIG. 1, three conductor terminals for connecting the outputs of a plurality of solar cells to a collection box are shown, (A) is a plan view, (B) is a side view, and (C) is a terminal. It is an end view of a compression part. It is a schematic block diagram of the solar energy power generation system containing the power transmission line which concerns on Embodiment 2 of this invention. FIGS. 2A and 2B show a modification of the terminal of FIG. 2, in which FIG. 2A is an end view of a compression portion of a four-conductor terminal, and FIG.

  Hereinafter, an embodiment of the present invention using a photovoltaic power generation system as a specific example of a green power system will be described with reference to the drawings. In the following embodiments, a solar power generation system including a power transmission line according to the present invention will be described, and the power transmission line according to the present invention will also be described in the process. In each figure, the same code | symbol is attached | subjected to the common or corresponding member.

[Embodiment 1: FIGS. 1 and 2]
<Outline of photovoltaic power generation system>
A photovoltaic power generation system 10 including a power transmission line of the present invention includes a solar cell array 100, a connection box 200, and a power conditioner 400. The DC power output from the plurality of solar cell arrays 100 is collected in the connection box 200, and the DC power output from the plurality of connection boxes 200 is collected and supplied to the power conditioner 400.

<Solar cell array>
The solar cell array 100 (hereinafter sometimes simply referred to as an array) is a group of solar cells in which a plurality of solar cell modules are assembled mechanically and electrically and attached to a gantry. In general, a plurality of solar cell modules are connected in series to form a string, and a plurality of strings are connected in parallel to form an array. Each known solar cell can be used for the solar cell module. Specifically, a silicon solar cell and a non-silicon (compound) solar cell can be used. There are two types of silicon-based solar cells: crystalline and amorphous. Among the former, single-crystalline ones have a relatively high conversion efficiency, and polycrystalline ones have a higher conversion efficiency than single-crystalline ones. Slightly inferior but economical. A large-area solar cell is easy to manufacture for an amorphous solar cell. On the other hand, compound solar cells are expensive, but are superior to single crystal solar cells in terms of conversion efficiency.

  Each of such arrays 111, 112, 121, and 122 outputs DC power, and the DC power is connected to the connection box 200 via a first cable connected to each of the arrays 111, 112, 121, and 122, and an aggregate terminal fitting that collects terminals of the cables. . In FIG. 1, the lines extending from the arrays 111, 112, 121, 122 toward the connection boxes 211, 212 correspond to the first cable.

<First cable>
The first cable constitutes a power transmission path between each of the arrays 111, 112, 121, 122 and the connection boxes 211, 212. As this cable, a PV (Photovoltaic Cable) cable can be suitably used. As a specific configuration example, a conductor, an insulating layer, and a sheath are provided in order from the center.

  The conductor is a conductor having a current capacity capable of flowing DC power output from the plurality of arrays 111, 112, 121, and 122. As specific examples of the conductor, an annealed copper strand, a tinned annealed copper strand, or the like can be suitably used.

  The insulating layer is a layer having a withstand voltage characteristic with respect to a working voltage of the conductor. As the material for the insulating layer, crosslinked polyethylene or flame-retardant crosslinked polyethylene can be suitably used.

  The sheath covers the outer periphery of the insulating layer and has a function of mechanically protecting the insulating layer. As the material for the sheath, in addition to heat resistant vinyl, flame retardant polyolefin such as flame retardant polyethylene, and flame retardant crosslinked polyolefin such as flame retardant crosslinked polyethylene can be suitably used.

<Aggregate terminal bracket>
Aggregate terminal fittings are attached to the terminals of the first cables (ends on the connection box side). As shown in FIG. 2, the aggregate terminal fitting 20 is a wing plate terminal that aggregates the conductors of a plurality of first cables into one terminal, and includes a compression portion 22 and a connection portion 24.

  The compression part 22 is a cylindrical member, and includes conductor holes 22H corresponding to the number of conductors of the plurality of first cables to be gathered. Each conductor hole 22H is a hole extending along the axial direction of the compression portion, and its center is provided at a position corresponding to the apex of the equilateral triangle. In this example, three conductor holes 22H are provided. However, the number of conductor holes 22H is not limited to three, and may be plural. Especially when there are three or more, the terminals of the first cable can be efficiently aggregated. That is, the number of first cables (the number of arrays 200 (FIG. 1)) gathered by the aggregate terminal fitting is not particularly limited. The conductor of the first cable is inserted into each of the conductor holes 22H, and the compression portion 22 is compressed from the outside by a compressor (not shown), thereby crimping the end of the first cable to the compression portion 22.

  On the other hand, the connection portion 24 is a rectangular plate-like member integrated with the compression portion 22 and includes an attachment hole 24H for attachment to a terminal block (not shown) of the connection box 200. A through hole is also formed in the terminal block of the connection box 200, and fixing the aggregate terminal fitting 20 to the connection box 200 by tightening the mounting hole 24H of the connection part and the through hole of the connection box 200 with a bolt (not shown). Is done. In this example, tin plating is applied to the surface of the connection portion 24 facing the terminal block (the right side surface of the connection portion 24 in FIG. 2B). Tin plating suppresses the surface of the aggregated terminal fitting 20 facing the terminal block from being oxidized, and suppresses an increase in resistance on the facing surface.

  The compression part 22 and the connection part 24 are made of a high conductivity material such as copper or copper alloy. In this example, a copper casting piece in which a cylindrical body and a rectangular plate are integrated is produced, and a conductor hole 22H is formed by cutting the cylindrical body, and a mounting hole 24H is formed by cutting the rectangular plate.

  In this way, the plurality of arrays 111, 112 or 121, 122 are assembled into a single aggregate terminal fitting 20 using a plurality of first cables and connected to the connection boxes 211, 212. In this power transmission path, a plurality of arrays 111 and 112 (121 and 122) are output devices, and a junction box 211 (212) to which a single aggregate terminal fitting 20 is attached is an input device.

  The connection box 200 includes a terminal block to which the aggregate terminal fitting 20 is connected, an array-side switch, an arrester, a backflow prevention element, and a main switch.

  The terminal block is a conductive member to which the connecting portion of the aggregate terminal fitting 20 described above is attached. This terminal block is made of, for example, a strip-shaped conductive material.

  The switches are provided as an array switch and a main switch on each of the array 100 side and the power conditioner 400 side. The former opens and closes between the individual arrays 111 and 112 (121 and 122) and the connection box 211 (212), and the latter opens and closes between the connection box 211 (212) and the power conditioner 400. These switches are used at the time of maintenance and inspection of the arrays 111, 112, 121, and 122.

  The arrester is provided to protect the main part of the power transmission path from a transient abnormal voltage caused by lightning or the like. The arrester is provided between each of the positive side and the negative side of the power transmission path and the ground.

  The backflow prevention element is an element for preventing current from flowing back through the arrays 111, 112, 121, and 122. Specifically, a diode or the like can be used.

<Second cable and aggregate terminal bracket>
Further, in this example, a plurality of connection boxes 200 are used, and DC power is collected using the connection boxes 211 and 212 as output devices and the power conditioner 400 as an input device. A second cable and an aggregate terminal fitting are used for this assembly. The configuration of the second cable can be the same as that of the first cable. In FIG. 1, a line extending from the right end of the connection boxes 211 and 212 toward the power conditioner is the second cable. The aggregate terminal fitting 20 shown in FIG. 2 used for the terminal of the first cable can be used in the same manner. Again, the number of second cables (number of connection boxes) aggregated by one aggregated terminal fitting 20 is not limited.

<Power conditioner>
The power conditioner 400 mainly has a function of controlling the output voltage of the array 200 so as to make maximum use of the DC power from the array 200 and converting it to a predetermined AC. This power conditioner includes a step-up chopper 410, an inverter 430, and a control circuit 430.

  The boost chopper 410 boosts the DC voltage output from the array 200 to a predetermined voltage and inputs it to the inverter. For example, a reactor, a diode, and a switching element are used for the boost chopper.

  The inverter 420 converts the DC power boosted to a predetermined voltage via the boost chopper 410 into AC having a predetermined frequency and outputs it. For example, a voltage-type current control inverter that controls the active / reactive power by current control with a constant input DC voltage can be used.

  The control circuit 430 controls the step-up chopper 410 and the inverter 420 and monitors and protects them. For example, the output voltage of the array 200 is subjected to MPPT control (maximum voltage point tracking control) in which the boost chopper 410 is controlled to operate at the optimum operating voltage, or the voltage and current of the inverter 420 are controlled.

<Other configuration>
In addition, the system 10 is provided with a transformer (not shown) between the power conditioner 400 and the system. With this transformer, the AC power output from the power conditioner 400 is transformed to a predetermined voltage and output to the system side. This transformer can also be provided integrally with the power conditioner 400.

<Effect>
According to the transmission line described above, when the DC outputs of the plurality of arrays 111, 112 (121, 122) are aggregated and input to the connection box 211 (212), the terminal fittings are attached to the individual cable terminals by using the aggregate terminal fitting 20. Compared with the case of providing, the number of terminal fittings can be reduced. In connection with it, the enlargement of the junction box 200 can be suppressed. This effect is similarly achieved by using the aggregate terminal fitting 20 when the DC outputs from the plurality of connection boxes 200 are aggregated and input to the power conditioner 400.

[Embodiment 2: FIG. 3]
Next, an embodiment different from the first embodiment will be described with reference to FIG. In the photovoltaic power generation system 10 having the power transmission line according to the second embodiment, a collection box 300 is provided between the connection box 200 and the power conditioner 400. In this system 10, DC power is collected by a third cable and an aggregate terminal fitting in a power transmission path having a plurality of connection boxes 211, 212 (221, 222) as output devices and a collection box 311 (321) as input devices. Further, in the power transmission path in which the plurality of collection boxes 311 and 321 are output devices and the power conditioner 400 is an input device, DC power is collected by the fourth cable and the aggregate terminal fitting. The structure of each connection box 211,212 (221,222) is similar to the structure of the connection box 211,212 (221,222) of the first embodiment, but is different in that it does not include a main switch.

  The collective box 311 (321) includes a main switch, which is so configured that the main switch in the connection box 200 of the first embodiment is taken out into another housing. By separating the connection box 200 and the collection box 300, each box can be miniaturized. In particular, when the number of connection boxes 200 is large, the degree of freedom of installation of the connection box 200 and the collection box 300 can be increased.

  The third cable corresponds to a line extending from the output side (right side) of each connection box 211, 212 (221, 222) in FIG. 3 to the assembly box 311 (321) side. On the other hand, the fourth cable corresponds to a line extending from the output side (right side) of the collection boxes 311 and 321 in FIG. 3 to the power conditioner 400 side. As the configuration of each of these cables, the same configuration as the first cable and the second cable shown in the first embodiment can be used.

  As the aggregated terminal fitting connected to each terminal of the third cable and the fourth cable, the same fitting as the aggregated terminal fitting 20 shown in FIG. 2 can be used.

  Even in such a transmission line, each terminal of a plurality of third cables (fourth cables) can be assembled into one aggregated terminal fitting, so the number of terminal fittings is larger than when terminal fittings are provided for each terminal of each cable. And the increase in size of the input device can be suppressed.

[Modified Embodiment: FIG. 4]
In addition, a modified example of the aggregate terminal fitting that can be used for the power transmission line of the present invention will be described with reference to FIG.

  Since this aggregate terminal fitting is different from the aggregate terminal fitting of FIG. 2 only in the configuration of the compression section, the following description will be mainly given to the compression section, and the other description will be omitted.

  The compression unit 22 illustrated in FIG. 4A includes a total of four conductor holes 22H. Each conductor hole 22H is provided at a position whose center corresponds to a substantially square apex. According to this aggregate terminal fitting, the conductors of any of the four first cables to the fourth cable can be gathered together.

  The compression section 22 shown in FIG. 4B includes a cross-shaped conductor hole 22H in which a total of four conductor holes are connected to each other. The cross-shaped hole as a whole can be said to be a single hole, but any of the conductors of the first cable to the fourth cable can be inserted into each of the radiating ends of the cross-shaped hole. Therefore, even with an aggregate terminal fitting having such a conductor hole 22H, any of the conductors of the four cables from the first cable can be gathered together.

  The above-described embodiment can be appropriately changed without departing from the gist of the present invention, and is not limited to the above-described configuration.

  The power transmission line of the present invention is a solar power generation system using a solar cell as a power generation means. Of the power transmission path from the solar cell to the power conditioner, cable terminals connected to a plurality of solar cells are combined into a power conditioner. It can be suitably used for aggregation.

10 Solar power generation system
100,111,112,121,122 Solar cell array (array)
200,211,212,221,222 Junction box
300,311,321 Meeting box
400 inverter
410 Boost chopper 420 Inverter 430 Control circuit
20 Aggregate terminal bracket
22 Compression part 22H Conductor hole 24 Connection part 24H Mounting hole

Claims (6)

A plurality of power generation means for outputting direct-current power derived from natural energy;
Power conversion means for converting the DC power into AC power;
A power transmission line of a green power system comprising a plurality of power generation means and a power transmission path between power conversion means,
A plurality of output devices included in the power transmission path;
A cable connected to each of these output devices,
Aggregate terminal fittings that gather these cable ends into one terminal,
With input equipment to which this aggregate terminal fitting is attached,
The aggregate terminal fitting is
A compression section that collectively compresses the conductors of the plurality of cables;
A transmission line of a green power system having a connecting portion that is integral with the compression portion and fixed to the input device. The output device is the power generation means;
The transmission line of the green power system according to claim 1, wherein the input device is a connection box to which DC power from the power generation means is input. The output device is a connection box to which DC power from the power generation means is input,
The transmission line of the green power system according to claim 1 or 2, wherein the input device is the power conversion means. The output device is a connection box to which DC power from the power generation means is input,
The transmission line of the green power system according to claim 1 or 2, wherein the input device is a collection box disposed between the connection box and the power conversion means. Comprising a junction box to which DC power from the power generation means is input;
The output device is a collection box arranged between the connection box and the power conversion means,
The transmission line of the green power system according to any one of claims 1, 2, and 4, wherein the input device is the power conversion means.   The transmission line of the green power system according to any one of claims 1 to 5, wherein the power generation means is a solar cell.

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