KR102010315B1 - Photovoltaic power generation system having high voltage switching board - Google Patents

Abstract

The present invention relates to a photovoltaic system with a high voltage switching board, which prevents the deterioration of power generation efficiency. The system comprises: a solar cell array consisting of a plurality of solar cell strings which are connected in series with a plurality of solar cell modules producing DC power from sunlight and has predetermined intervals; a solar connection board which connects each solar cell string of the solar cell array and collects DC power produced from each solar cell module; an inverter receiving DC power collected in the solar connection board and converting the DC power into AC power to output the converted AC power; and a plurality of high voltage switching boards configured at a front end of the solar connection board and including a relay to open or close the circuit between each of the solar cell strings and the solar connection board and a protection circuit portion for protecting, from potential differences, an instrument connected from the outside. A rod is connected to each of the high voltage switching boards to attach and detach the instrument and these rods sequentially control each of the high voltage switching boards.

Description

Solar Power System with High Voltage Switching Board {PHOTOVOLTAIC POWER GENERATION SYSTEM HAVING HIGH VOLTAGE SWITCHING BOARD}

The present invention relates to a photovoltaic power generation system, and more particularly, to a photovoltaic power generation system having a high voltage switching board for preventing a decrease in power generation efficiency through failure diagnosis of a solar cell module.

In recent years, countries around the world have been focusing on low-carbon green technology and green industries as new growth engines to overcome climate change crisis caused by increased fossil fuel use, global population growth, and energy and resource crisis caused by the rapid growth of BRICs. The era of growth is being adopted as a paradigm for new national development.

In other words, green growth is to escape from the stereotype that environment and economy are in conflict, maximizing the synergy between them, contributing to the improvement of the environment, and converting the environment into a growth engine. do.

As one of the specific driving directions for green growth, photovoltaic power generation systems are in the spotlight as one means of realizing petroleum and energy independence. In general, photovoltaic power generation is implemented in the form of power generation that receives sunlight and produces electricity in a solar cell made of a semiconductor material. In other words, the photovoltaic power generation system generates power by directly converting light energy from the sun into electrical energy.

The photovoltaic power generation system converts light energy into electrical energy, and includes a solar panel (module) for converting light energy into electrical energy and an inverter for converting DC power produced in the solar panel into AC power. .

A more detailed description of the configuration of the solar power generation system includes a solar cell module supplying a direct current power corresponding to the received solar light, a solar cell array connected in series, and a large number of wirings between the solar cell array and the inverter. It consists of a solar connection panel that facilitates wiring and performs various protection functions, an inverter that converts the DC power generated in the solar cell array into AC power, and a load that consumes the generated power.

When the solar power generation system becomes large in capacity, a large number of wires are required when connecting the inverters by extending the wires for each solar module, thereby forming a junction box serving as a terminal box for each solar module and connecting the junction boxes to each other. Electricity produced by optical modules can be connected to inverters and storage batteries.

1 is a view showing a general solar cell module, Figure 2 is a view showing a junction box attached to the back of the solar cell module of FIG.

In the solar cell module illustrated in FIG. 1, the solar cells are arranged in six rows and are arranged in columns of 12 lines, and the standard is represented by 6 * 12 columns.

Such a solar cell module is connected to the ribbon of the junction box as shown in FIG. 2 by connecting two rows of rows as one block in series between rows and rows. That is, the + and-wires from the three blocks 1a, 1b and 1c are connected to the four ribbons.

At this time, when the voltage produced in the intermediate block 1b is higher than the voltage produced in the first block 1a, the electricity produced in the intermediate block 1b is the first block in the ribbons 11b and 11c to which the intermediate block 1b is connected. (1a) may flow toward the connected ribbons 11a and 11b. To prevent this case, a diode 12 is formed in the housing 10 which serves as a bypass between the ribbon and the ribbon.

Here, the diode 12 prevents current from flowing in the reverse direction to prevent damage of the solar cell.

The junction box includes a housing 10 having a ribbon 11 and a diode 12 embedded therein, a cover 20 fastened to the housing 10 to prevent penetration of water or impurities, and one side ribbon 11; And a connected cable 14 and a connector (not shown).

When the junction box is not normally produced due to the abnormality of the solar cell module, the cover 20 is opened and the current flow is checked by using a check device such as a tester between the ribbons 11 of the housing 10. There is discomfort to be done.

That is, in the solar cell module, since one block is connected between the ribbon and the ribbon as described above, in the case of the solar panel 1 including three blocks 1a. 1b and 1c as shown in FIG. The current flow between the ribbon should be checked three times.

In addition, the cover 20 is coupled with a plurality of hooks (13, 23), etc. to maintain a firm coupling state with the housing 10 to prevent the penetration of water or impurities, the cover 20 in the housing 10 Separation is also not easy.

After all, in the case of a solar cell module in which a plurality of solar panels are formed, if you want to check the solar panel due to the decrease in power generation, open the cover 20 of the junction box formed for each solar module and check the amount and flow of electricity with a tester. Since the cover 20 must be fastened to the housing 10 again, a lot of time is spent on the inspection and the inspection work is very cumbersome.

Therefore, in order to diagnose the abnormality of the solar cell module according to the prior art, the measurement and status judgment are inefficient and take a long time because the connection between the solar cell module and the inverter is temporarily turned off and the measurement must be performed while the power generation is stopped. Even when the solar module is operating normally, the connection with the inverter is turned off, which does not produce power, resulting in a decrease in power generation efficiency.

The present invention was derived to solve the above problems, having a high voltage switching board in front of the solar connection panel to measure the current and voltage curve during the generation of the solar cell string and at night when the solar power generation is not in progress It is an object of the present invention to provide a photovoltaic power generation system having a high voltage switching board to prevent a decrease in power generation efficiency by applying DC power to a solar cell string and diagnosing failure through electroluminescent image measurement on a string basis.

A solar power generation system having a high voltage switching board according to the present invention for achieving the above object is a plurality of solar cells having a constant interval and a plurality of solar cell modules are connected in series to produce and output DC power from sunlight Delivers a solar cell array consisting of a cell string, a solar connection panel connecting each solar cell string of the solar cell array to collect direct current power produced from each solar cell module, and a direct current power source collected on the solar connection panel. An inverter that receives and converts into an AC power source and outputs the relay; and a relay configured to open or close the solar cell strings and the solar connection panel and a measuring instrument connected externally to protect against potential difference. With a plurality of high voltage switching board comprising a circuit portion And, is connected to each of the high-voltage switching board, it characterized in that the instrument is detachable and provided with a rod for controlling the high-voltage switching each board in sequence.

Photovoltaic power generation system with a high voltage switching board according to an embodiment of the present invention has the following effects.

First, a high voltage switching board is provided at the front of the solar panel and a rod is installed on the high voltage switch board to measure the current and voltage curves during the generation of the solar cell string through the rod, and at night when the solar power generation is not in progress. By applying a DC power source to the solar cell string and diagnosing the fault through electroluminescent image measurement on a string basis, a reduction in power generation efficiency can be prevented.

Second, by using the high voltage switching board connected to the front end of the solar panel or inverter during the solar power generation facilities, it is possible to measure the voltage and current curve in real time without affecting the solar power situation.

Third, a protection circuit may be configured on the high voltage switching board to protect the instrument connected to the load.

Fourth, when the instrument connected to the load of the high voltage switching board is connected, the voltage and current curves are measured by temporarily closing the solar cell string array and the solar connection panel to measure the voltage value, the current value, and the power (production). I can confirm it.

1 is a view showing a typical solar cell module
FIG. 2 is a view illustrating a junction box attached to a rear surface of the solar cell module of FIG. 1. FIG.
Figure 3 is a schematic view showing a solar power system having a high voltage switching board according to the present invention
4 is a view illustrating a form in which voltage and current curves are measured by connecting to the rod of FIG.
5 is a screen photographing the emission image of the solar cell module by applying the DC power through the rod of FIG.
FIG. 6 is a graph illustrating a state in which voltage and current curves of a solar cell string are measured by the measuring instrument of FIG. 3.

As the invention allows for various changes and numerous embodiments, particular embodiments will be illustrated in the drawings and described in detail in the written description. However, this is not intended to limit the present invention to specific embodiments, it should be understood to include all transformations, equivalents, and substitutes included in the spirit and scope of the present invention. In the following description of the present invention, if it is determined that the detailed description of the related known technology may obscure the gist of the present invention, the detailed description thereof will be omitted.

The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting of the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this application, the terms "comprise" or "have" are intended to indicate that there is a feature, number, step, operation, component, part, or combination thereof described in the specification, and one or more other features. It is to be understood that the present invention does not exclude the possibility of the presence or the addition of numbers, steps, operations, components, components, or a combination thereof.

Figure 3 is a schematic diagram showing a solar power system having a high voltage switching board according to the present invention.

In the photovoltaic power generation system having a high voltage switching board according to the present invention, as shown in FIG. 3, a plurality of solar cell modules 110 that produce and output DC power from sunlight are connected in series and have a predetermined interval. The solar cell array 100 including a plurality of solar cell strings 120 and the respective solar cell strings 120 of the solar cell arrays 100 are connected to collect DC power generated from each solar cell module 110. In front of the solar connection panel 200, the inverter 300 that receives the DC power collected in the solar connection panel 200, converts into AC power and outputs the alternating current. And a protection circuit unit 420 for protecting an instrument connected from the outside with a relay 410 for OPEN or CLOSE between each of the solar cell strings 120 and the solar connection panel 200. A load (430) having a plurality of high voltage switching boards (400), connected to each of the high voltage switching boards (400), to which the instrument is attached and detached and to sequentially control the high voltage switching boards (400). Equipped.

Here, the measuring instrument can measure the voltage and current curves of each of the solar cell strings 120 to diagnose the failure according to the voltage value, current value, power value, and curve shape of each solar cell string.

The relay 410 when the measuring instrument is connected to the rod 430 is OPEN between each of the solar cell string 120 and the solar connection panel 200 in less than 100 ㎳ time through the rod 430 The voltage and current curves of each solar cell string 120 are measured sequentially.

In addition, at night when the solar cell array 100 is not generated, OPEN is operated by operating the relay 410 between each of the solar cell strings 120 and the solar panel 200 and the DC through the rod 430. Power is applied and the image of the solar cell module 110 is measured.

The relay 410 performs the opening and closing operation according to the control signal of the measuring instrument connected to the rod 430. That is, the relay 410 recognizes when the measuring instrument is connected to the rod 430, and sequentially opens the voltage between the solar cell string 120 and the solar connection panel 200 while measuring voltage and current together with the DC power supply. Allow to be authorized.

When the protection circuit unit 420 measures the voltage and current curves of the respective solar cell strings 120, the protection circuit unit 420 opens the open circuit between the solar cell strings 120 and the solar connection panel 200 with the relay 410. Up to 1000V ~ 10A flows during photovoltaic power generation to prevent damage to the instrument.

Here, the solar cell module 110 generates direct current power by converting solar energy into electrical energy in a state consisting of a plurality of solar cells.

The solar cell collects sunlight incident from the outside to generate electricity, and typically silicon and a composite material are used. Specifically, the solar cell is used by bonding a P-type semiconductor and an N-type semiconductor to use the photoelectric effect of producing electricity by receiving sunlight. Most solar cells are composed of a large area P-N junction diode, and the electromotive force generated at the anode end of the P-N junction diode is connected to an external circuit.

The minimum unit of the solar cell is called a cell, and in practice, the solar cell is rarely used as it is. Although the voltage required for actual use is from a few V to tens or hundreds of V, the voltage from one cell is about 0.5V, which is very small. This is why multiple unit photovoltaic arrays can be connected in series or in parallel to the required unit capacity. I use it. In addition, when solar cells are used outdoors, they face various harsh environments, and thus, a plurality of cells are packaged and used to protect a plurality of cells connected to a required unit capacity in a harsh environment.

The solar panel 200 is installed between the solar cell array 100 and the inverter 300 to be operated in a state in which the solar power generation system is optimized to obtain the maximum output from the solar cell array 100. Perform electrical monitoring or protection functions.

To this end, various protection devices are provided inside the solar panel 200 to prevent imbalances in power generation characteristics of the light collecting plate due to other factors such as changes in the surrounding environment. In addition, the protection device includes a reverse voltage prevention means 220 made of a reverse voltage prevention diode for blocking a current flowing in a reverse direction to protect a circuit of an input / output terminal, and an overcurrent protection fuse 210 for protecting a circuit by blocking an overcurrent. And the like.

In other words, the inverter 300 is also called a converter or PCS. The inverter 300 converts DC energy, which is electrical energy generated and supplied from the solar module 100, into AC energy, and supplies a DC / AC inverter. Include. The DC / AC inverter converts and outputs an AC power set by a high frequency switching method using various semiconductor switching elements such as SCR, Transistor, IGBT, and GTO (Gate to Turn Off SCR).

The image measuring unit for measuring the electroluminescence image is detachable by applying DC power to each solar cell module 110 through each solar cell string 120 at night when the solar power generation is not performed on the rod 430. The image measuring unit includes a power supply unit applying DC power to each of the solar cell strings 120, and a photographing unit photographing an image of each solar cell module by DC power applied through the power supply unit.

 The high voltage switching board 400 has an input connected to the output terminals of the solar cell string 120 and an output connected to the input terminals of the solar connection panel 200, respectively.

The protection circuit unit 420 is configured by connecting at least one resistor and a diode in series between the rod 430 and the output unit.

The rod 430 controls each of the high voltage switching boards 400 at a time of 100 kΩ or less to sequentially measure voltage and current curves of the respective solar cell strings 120 through the measuring instrument.

The photovoltaic power generation system having the high voltage switching board according to the present invention configured as described above has a high voltage switching board 400 and a string connection line configured in the solar connection panel 200 at a time when the solar cell module 110 does not generate power. When connecting one-to-one and measuring current and voltage curves of the solar cell module 110 without disturbing the generation of the solar cell module 110 during the power generation time, switching operation and current and voltage measurement are performed within 100 ms. It does not affect the photovoltaic situation.

In addition, the already connected high voltage switching board 400 may be used to find a solar cell module in which a PID phenomenon occurs by measuring an electroluminescence image in units of strings by applying DC power at night.

According to the present invention is a system for inspecting the solar cell module 110 installed in the photovoltaic power station in the unit of the solar cell string 120, the high voltage switching board 400 without interrupting the power generation in the situation of solar power generation By using it to measure the state of the solar cell module 110 can be usefully applied to the solar module maintenance inspection equipment.

4 is a view illustrating a form in which voltage and current curves are measured by connecting to the rod of FIG. 3.

As shown in [1] of FIG. 4, it can be seen that the PID phenomenon, which is corrosion of the solar cell module due to a high potential difference, appears when the measured voltage-current curve B is lower than the normal voltage-current curve A as a whole. have.

In addition, in some solar cell modules of the solar cell module connected to the solar cell string when the right side of the measured voltage-current curve (B) is lower than the normal voltage-current curve (A), as shown in [2] of FIG. It can be seen that the bypass diode is defective and the connection between the solar cell modules connected to the solar cell string is poor.

As shown in [3] of FIG. 4, it can be seen that a hot spot phenomenon occurs in the solar cell module connected to the solar cell string when the disturbance occurs in the right side of the measured voltage-current curve B. FIG.

In addition, as shown in [4] of FIG. 4, when the disturbance occurs in the upper side of the measured voltage-current curve B, the current output unevenness between the solar cell modules connected to the solar cell string, that is, the shade of some solar cell modules It can be seen that contamination has occurred.

FIG. 5 is a screen photographing an emission image of a solar cell module by applying DC power through the rod of FIG. 1.

As shown in FIG. 5, when deterioration occurs in a solar cell module when DC power is applied to each string of solar cells through a load at night when no solar power is generated, black appears as shown above due to the PID phenomenon. If there is no phenomenon, there will be no black parts as shown below.

Through this, the solar cell module can be diagnosed in string units while viewing the image image.

FIG. 6 is a graph illustrating a state in which voltage and current curves of a solar cell string are measured through the measuring apparatus of FIG. 3.

As shown in FIG. 6, the voltage and current curves of the respective solar cell strings are measured and compared with the reference voltage and current curves according to the curve shape, and the voltage (V) and the current (A) (Current) of each solar cell string. It is possible to diagnose the failure of the power (W).

On the other hand, what has been described above is only one embodiment for carrying out the present invention, the present invention is not limited to the above embodiment, the present invention without departing from the gist of the invention claimed in the claims below Anyone with ordinary knowledge in the field will have the technical spirit of the present invention to the extent that various modifications can be made.

100: solar cell array 200: solar panel
300: inverter 400: high voltage switching board

Claims (7)

A solar cell array comprising a plurality of solar cell strings connected in series and having a predetermined interval, in which a plurality of solar cell modules for producing and outputting DC power from sunlight;
A solar connection panel connecting the respective solar cell strings of the solar cell array to collect DC power produced from each solar cell module;
An inverter for receiving the DC power collected in the solar panel and converting the AC power into an AC power;
A plurality of high voltage switching boards configured at a front end of the solar connection panel and including a relay for OPEN or CLOSE between each of the solar cell strings and the solar connection panel and a protection circuit for protecting an instrument connected from the outside from potential differences; Equipped,
A rod connected to each of the high voltage switching boards, the meter being detachable and sequentially controlling the high voltage switching boards;
The image measuring unit which attaches DC power to each solar cell module through each of the solar cell strings and measures the electroluminescent image is detached at night when no solar power is generated to the rod.
The protection circuit unit is configured by connecting at least one resistor and a diode in series between the rod and the output unit,
The relay controls the high voltage switching board at a time of 100 kΩ or less when the meter is connected to the load, and sequentially measures the voltage and current curves of the respective solar cell strings through the meter. PV system with switching board. The high voltage of claim 1, wherein the measuring instrument measures a voltage and a current curve of each of the solar cell strings and diagnoses the failure according to a voltage value, a current value, a power value, and a curve shape of each of the solar cell strings. PV system with switching board. delete The photovoltaic power generation system of claim 1, wherein the high voltage switching board includes an input unit connected to each of the output terminals of the solar cell string and an output unit connected to the input terminal of the solar panel. system. delete The method of claim 1, wherein the image measuring unit comprises a power supply unit applying DC power to each of the solar cell strings, and a photographing unit photographing an image of each solar cell module by DC power applied through the power supply unit. A photovoltaic power generation system with a high voltage switching board. delete

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