JP2008271693A - Solar photovoltaic power-generation system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To simplify wiring for an abnormality detection function in a solar photovoltaic power-generation system having the abnormality detection function by a relative comparison method of output current. <P>SOLUTION: The solar photovoltaic power-generation system is provided with a plurality of string arrays 2 constituted of a plurality of solar battery strings 11 and an inverter 5 converting DC power generated by the solar battery string into AC power. A connection box 3 connecting outputs of a plurality of solar battery strings in the string arrays in parallel is arranged in each string array. In an abnormality detection device 6, one of a plurality of string arrays is set to be an index string array, and the index string array is compared with respective string arrays except the index string array with respect to the output current from the connection box so as to detect abnormality in the respective string arrays. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a photovoltaic power generation system, and more particularly to a photovoltaic power generation system suitable for increasing the scale.

  A solar power generation system is generally configured to include a solar cell string having a configuration in which solar cell modules are connected in series and an inverter (interconnection inverter) that converts DC power generated by the solar cell module into AC power. The scale can be expanded by increasing the number of installations.

  Such a photovoltaic power generation system can function most efficiently when any of the plurality of solar cell strings is operating normally. Therefore, in a photovoltaic power generation system, it is desirable to be able to quickly respond to any of a plurality of solar cell strings when an abnormality such as a failure or a light reception failure occurs. Need to be automatically detected.

  It is effective to perform automatic abnormality detection of the solar cell strings by relative comparison of output currents of the solar cell strings. That is, any one of a plurality of solar cell strings, for example, the solar cell string having the maximum output current is used as an indicator, and the output current of other solar cell strings is compared with the output current of the solar cell string for the indicator. In this method, the presence or absence of abnormality is determined and detected for each solar cell string.

  For example, Patent Documents 1 to 3 disclose such an abnormality detection technique. In these conventional abnormality detection techniques, abnormality of each solar cell string is detected by an abnormality detection device provided in the casing of the inverter. That is, the abnormality detection is performed by relative comparison of the output current of each solar cell string while measuring the output current in the wiring path of each solar cell string connected to the inverter.

JP 9-28084 A JP 2000-217259 A Japanese Patent Laid-Open No. 10-63358

  The photovoltaic power generation system is an energy system that is friendly to the global environment, and its further spread is desired. One effective means for further spreading the photovoltaic power generation system is to increase the scale of the photovoltaic power generation system. The scale expansion of the photovoltaic power generation system can be performed by increasing the number of installed solar cell strings as described above. For example, a certain number of solar cell strings are grouped as a string array, and a plurality of string arrays are provided. Can be done in the form.

  As the scale of such a solar power generation system increases, there is a problem that the amount of wiring becomes enormous. In particular, when the abnormality detection function based on the relative comparison method of the output current described above is provided, wiring for the abnormality detection function is also required. Therefore, the abnormality detection function is provided in the casing of the inverter as in the prior art described above. With the configuration, enlarging the amount of wiring becomes a bigger problem, and improvement is desired.

  The present invention has been made in the background as described above, and the problem is that the photovoltaic power generation system can simplify the wiring, and particularly has a function of detecting abnormality by a relative comparison method of output currents. The purpose of the system is to simplify the wiring associated with the abnormality detection function.

  In the present invention, in order to solve the above-described problem, a photovoltaic power generation including a plurality of string arrays including a plurality of solar cell strings and an inverter that converts DC power generated by the solar cell strings into AC power. In the system, a connection box for connecting the outputs of the plurality of solar cell strings in the string array in parallel is provided for each of the string arrays, and any one of the plurality of string arrays is an index string array, An abnormality detection device is provided for detecting an abnormality of each string array by comparing the index string array with each other string array for the output current from the connection box. It is said.

  In this way, abnormality detection by the relative comparison method of the output current is performed in units of string arrays in which a plurality of solar cell strings are grouped, so that the number of wirings for abnormality detection can be reduced. Wiring associated with detection can be simplified. In addition, since the connection box is provided for each string array, the connection box can be installed close to the string array, so the wiring distance of the power output line to the connection box can be shortened, As a result, the wiring of the power output line can be simplified.

  Further, in the present invention, in order to solve the above-described problem, solar light including a plurality of string arrays including a plurality of solar cell strings and an inverter that converts DC power generated by the solar cell strings into AC power. In the power generation system, a connection box for connecting the outputs of the plurality of solar cell strings in the string array in parallel is provided for each of the string arrays, and any one of the plurality of solar cell strings in the string array is used as an indicator. An abnormality of each solar cell string in the string array is detected by comparing the output current of the index string with the output current of the other solar cell string, and a plurality of strings in the string array. Solar cell string When a malfunction occurs in any of the string array anomaly detection apparatus can output the anomaly notification units of is characterized in that provided for each of the string array.

  In this way, by providing each string array with an abnormality detection device that detects the presence or absence of abnormality for each of the solar cell strings in the string array, while simplifying wiring associated with abnormality detection, the human burden associated with abnormality monitoring Can be reduced. In other words, by providing an abnormality detection device for each string array, the abnormality detection device can be installed close to the string array, and therefore the wiring distance for abnormality detection can be shortened. In addition, the wiring associated therewith can be simplified, and on the other hand, abnormality detection can be performed for each solar cell string, so that it is easy to identify an abnormal solar cell string, and the human burden associated with abnormality monitoring can be reduced. In addition, since the connection box is provided for each string array, the connection box can be installed close to the string array, so the wiring distance of the power output line to the connection box can be shortened, As a result, the wiring of the power output line can be simplified.

  For the solar power generation system as described above, it is preferable to provide a DC current collector for connecting the outputs from the connection boxes for each string array in parallel between the connection box and the inverter. Thus, it is possible to reduce the power output lines having a long distance, and it is possible to further increase the simplification of the wiring for the power output lines.

  According to the present invention as described above, with respect to a photovoltaic power generation system having an abnormality detection function based on a relative comparison method of output currents, wiring associated with the abnormality detection function can be simplified.

  Hereinafter, modes for carrying out the present invention will be described. In FIG. 1, the structure of the solar energy power generation system by 1st Embodiment is shown. The photovoltaic power generation system 1 of this embodiment includes a plurality of string arrays 2 (2-1, 2-2,..., 2-n) and a plurality of connection boxes 3 (3-1, 3-2,..., 3-n). A DC current collector panel 4, an inverter 5, an abnormality detection device 6, and a solar cell monitoring panel 7.

  The string array 2 is configured by grouping a certain number of solar cell strings 11 in which a plurality of solar cell modules are connected in series, and the solar cell strings 11-1, 11-2,. A string output line (power output line) 12 is connected to each.

  The connection box 3 is provided for each string array 2 and collects power by connecting the output powers of the solar cell strings 11-1, 11-2,..., 11-n in parallel, and the collected power Is output to the DC current collector 4 through the connection box output line (power output line) 13. Here, in relation to the connection box 3 as described above, the string array 2 is a solar cell string group in which one connection box 3 collects current. That is, a group of solar cell strings 11 connected in parallel in one junction box 3 forms one string array 2.

  The DC current collector 4 collects power by connecting the outputs from the connection boxes 3-1, 3-2,... 3 -n in parallel, and outputs the collected power to the inverter 5.

  The inverter 5 converts the DC power generated by the solar cell string 11 and collected by the DC current collector 4 into AC power. The output of the inverter 5 is connected to, for example, a power distribution system 14 and supplied to a load 15 in the system 14.

  The abnormality detection device 6 detects an abnormality in the string arrays 2-1, 2-2,. Therefore, the abnormality detection device 6 includes an A / D conversion unit 16, an abnormality detection unit 17, and an abnormality notification output unit 18, as shown in FIG.

  The A / D converter 16 applies direct current to the connection box output lines 13 of the connection boxes 3-1, 3-2,..., 3-n corresponding to the string arrays 2-1, 2-2,. The measurement outputs 22-1, 222-2,..., 22-n of the current detection devices 21 provided upstream of the current collector panel 4 are A / D converted and input to the abnormality detection unit 17.

  The abnormality detection unit 17 determines the presence / absence of abnormality for each of the string arrays 2-1, 2-2,... 2 -n by using the measurement outputs 22-1, 22-2,. Detect something as an abnormal array. Specifically, the string array 2-1, 2-2,..., 2-n having the maximum output current is selected and used as an index array. Here, it is assumed that the string array 2-1 is an index array. When the index array is determined, the difference between the output current of the string array 2-1 and the output current of the string arrays 2-2,..., 2-n other than the index array is calculated. Then, each difference is compared with a predetermined reference value. For example, if the difference of the string array 2-2 exceeds the reference value, it is determined that the string array 2-2 is abnormal, and this is regarded as an abnormal array. To detect.

  Here, the solar cell string 11 may transiently reduce the output due to a foreign substance temporarily adhering to the light receiving surface or a temporary light shielding state. Since such a transient output decrease is not abnormal, it is necessary to be able to avoid judging this as abnormal. Therefore, the output current comparison for abnormality determination is performed with a predetermined time width. For this purpose, for example, a difference comparison is performed for the current integrated value for a predetermined time, or it can be determined that there is an abnormality on the condition that a state where the difference exceeds the reference value continues for a predetermined time.

  When the abnormality array is detected as described above, the abnormality detection unit 17 outputs the result to the abnormality notification output unit 18. In response to this, the abnormality notification output unit 18 outputs an abnormality notification signal to notify the abnormality. The abnormality notification is made by changing the display color in the display unit 23 provided in the abnormality detection device 6, and the display unit 24 provided in the solar cell monitoring panel 7 installed at a remote location for remote monitoring. This is done by changing the display color.

  As described above, in the photovoltaic power generation system 1, abnormality detection is performed by the relative comparison method of the output current with the string array 2 in which a plurality of solar cell strings 11 are grouped as a unit. Therefore, the number of abnormality detection wirings can be reduced, and the wiring associated with abnormality detection can be simplified. Further, in the photovoltaic power generation system 1, the connection box 3 is provided for each string array 2, so that the connection box 3 can be installed close to the string array 2. The wiring distance of 12 can be shortened, thereby simplifying the wiring for the power output line. Further, in the photovoltaic power generation system 1, for providing the connection box 3 for each string array 2, a DC current collector 4 for connecting the connection box output lines 13 of the connection boxes 3 in parallel is provided. In this case, it is possible to install the DC current collector panel 4 close to the junction box 3, so that the wiring distance of the junction box output line 13 can be shortened, and the wiring for the power output line can be simplified. It can be further increased.

  In FIG. 2, the structure of the solar energy power generation system by 2nd Embodiment is shown. In the photovoltaic power generation system 31 of the present embodiment, the abnormality detection device 6 is provided for each string array 2 as the abnormality detection devices 6-1, 6-2, ... 6-n, and the abnormality detection device 6-1. , 6-2,... 6 -n The solar power generation according to the first embodiment is provided except that an abnormality notification relay device 32 that relays each abnormality notification signal and outputs it as one abnormality notification signal is provided. Similar to system 1.

  The abnormality detection device 6 has the same configuration as that described above with reference to FIG. 2, and the abnormality of the solar cell strings 11-1, 11-2,. When an abnormality is detected in any of the solar cell strings 11-1, 11-2,..., 11-n in the string array 2, an abnormality notification is output with the string array 2 as a unit.

  In other words, the A / D conversion unit 16 has the measurement outputs 34 of the current detection devices 33 provided on the string output lines 12 of the solar cell strings 11-1, 11-2,. -1, 34-2,..., 34-n are input, A / D converted, and input to the abnormality detection unit 17.

  The abnormality detection unit 17 determines the presence / absence of abnormality in the solar cell strings 11-1, 11-2,... 11-n by using the measurement outputs 34-1, 34-2,. Detect something as an abnormal string. Specifically, first, the solar cell string 11-1, 11-2,... 11-n having the maximum output current is selected and used as an index string. Here, it is assumed that the solar cell string 11-1 is an index string. When the index string is determined, the difference between the output current of the solar cell string 11-1 other than the index string and the output current of the solar cell string 11-1 is calculated for each of the output currents of the solar cell strings 11-2,. Then, each difference is compared with a predetermined reference value. For example, if the difference of the solar cell string 11-2 exceeds the reference value, it is determined that the solar cell string 11-2 is abnormal, and this is abnormal. Detect as a string. Here, the output current comparison for abnormality determination is performed in a predetermined time width as described above.

  When an abnormal string is detected as described above, the abnormality detection unit 17 outputs the result to the abnormality notification output unit 18. In response to this, the abnormality notification output unit 18 outputs an abnormality notification signal with the string array 2 as a unit to notify the abnormality. Abnormality notification is performed in the same manner as described in the first embodiment. However, the transmission of the abnormality notification signal to the display unit 24 of the solar cell monitoring panel 7 is performed via a relay by the abnormality notification relay device 32.

  As described above, in the solar power generation system 31, the abnormality detection device 6 is provided for each string array 2 so that the presence or absence of abnormality can be detected for each of the solar cell strings 11 in the string array 2. Therefore, it is possible to reduce the human burden associated with abnormality monitoring while simplifying wiring associated with abnormality detection. That is, by providing the abnormality detection device 6 for each string array 2, it is possible to shorten the distance of wiring relating to abnormality detection, thereby simplifying the wiring associated with abnormality detection, while solar cell strings. Since abnormality detection can be performed in units of 11, it is easy to identify abnormality strings, and the human burden associated with abnormality monitoring can be reduced. Further, the solar power generation system 31 includes an abnormality notification relay device 32 that outputs each abnormality notification signal of 6-1, 6-2,..., 6-n provided for each string array 2 as one abnormality notification signal. . For this reason, it is possible to simplify the wiring for transmitting the abnormality notification signal to the solar cell monitoring panel 7 installed at a remote location for remote monitoring. In addition to these, in the photovoltaic power generation system 31, the same wiring simplification effect as that in the above-described photovoltaic power generation system 1 can be obtained.

  As mentioned above, although the form for implementing this invention was demonstrated, these are only typical examples, This invention can be implemented with various forms in the range which does not deviate from the meaning.

It is a figure which shows the structure of the solar energy power generation system by 1st Embodiment. It is a figure which shows the structural example of an abnormality detection apparatus. It is a figure which shows the structure of the solar energy power generation system by 2nd Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Solar power generation system 2 String array 3 Connection box 5 Inverter 6 Abnormality detection apparatus 11 Solar cell string 31 Solar power generation system

Claims (3)

In a photovoltaic power generation system comprising a plurality of string arrays composed of a plurality of solar cell strings, and having an inverter that converts DC power generated by the solar cell strings into AC power,
A connection box for connecting the outputs of the plurality of solar cell strings in the string array in parallel is provided for each of the string arrays, and any one of the plurality of string arrays is used as an index string array, from the connection box And an abnormality detector that detects an abnormality of each string array by comparing the index string array with each of the other string arrays. Photovoltaic system. In a photovoltaic power generation system comprising a plurality of string arrays composed of a plurality of solar cell strings, and having an inverter that converts DC power generated by the solar cell strings into AC power,
A connection box for connecting the outputs of the plurality of solar cell strings in the string array in parallel is provided for each of the string arrays, and any one of the plurality of solar cell strings in the string array is used as an index string, An abnormality of each solar cell string in the string array is detected by comparing an output current of the indicator string and an output current of the other solar cell string, and a plurality of solar cell strings in the string array An abnormality detection device is provided for each of the string arrays so that an abnormality notification in units of the string array can be output when any of the strings becomes abnormal. .   3. The sun according to claim 1, wherein a DC current collector for connecting the outputs from the connection box for each string array in parallel is provided between the connection box and the inverter. Photovoltaic system.

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