JP6393732B2 - Solar power generation monitoring device and solar power generation monitoring method - Google Patents

Description

  The present invention relates to a photovoltaic power generation monitoring device and a photovoltaic power generation monitoring method.

  In recent years, in addition to the depletion of fossil fuels, global environmental problems such as global warming have become serious, so solar power generation, which is clean energy, has attracted attention. In solar power generation, a solar battery panel (solar battery module) in which a plurality of solar batteries (cells) are arranged in a panel shape is used.

  In a large-scale photovoltaic power generation facility, a plurality of solar cell modules are connected in series to form a solar cell string, and the plurality of solar cell strings are connected in parallel to a power conditioner. The power conditioner converts the direct current generated by the solar cell module into an alternating current, and always maintains the electric power obtained from the solar cell module at the maximum value.

  Various data related to power generation such as current value and power generation amount are sent to the monitoring server in real time. The monitoring server monitors the power generation status of the entire power generation equipment such as the power conditioner and the solar battery string, and notifies the solar power generation equipment manager when an abnormality occurs.

  For example, in Patent Document 1, the average power generation amount per unit time is calculated, the average power generation amount converted per unit area is divided by the average solar radiation amount to obtain the conversion efficiency, and the conversion efficiency for generating the daily conversion efficiency data Based on the daily conversion efficiency data of the generator and the predetermined period, calculate the average conversion efficiency for each predetermined temperature band, add the fluctuation range to the calculated average conversion efficiency, and multiply by the aging degradation coefficient for each temperature band The average temperature is a predetermined temperature band for each unit time based on a determination value generation unit that generates temperature band-specific data and a daily conversion efficiency data in a deterioration diagnosis corresponding period corresponding to a predetermined period. If the conversion efficiency falls below the determination value, it is determined whether or not the conversion efficiency is below the determination value. Device disclosed To have.

  Patent Document 2 also describes a power generation efficiency calculation unit that calculates power generation efficiency using the amount of power generated by the solar power generation panel, and an ideal value of power generation efficiency using the amount of solar radiation and the panel temperature of the solar power generation panel. An ideality calculation unit that calculates a ratio between the power generation efficiency calculated by the power generation efficiency calculation unit and the ideal value as an ideality, and a determination unit that determines whether or not the ideality has decreased over time. A solar power management device is disclosed.

JP 2014-176195 A JP 2015-47030 A

In the technique described in Patent Document 1, since the influence of dirt on the surface of the solar cell module is not taken into consideration when calculating the determination value, the determination value may be evaluated lower than the power generation capability that the solar cell module originally has. There is. As a result, even if deterioration or failure occurs in the solar cell module, it is not determined as abnormal, and there is a possibility that discovery of the abnormality is delayed.
On the other hand, in the technique described in Patent Document 2, since time is required for analysis based on the transition of the ideality with time, there is a concern about a delay in judgment for sudden failure such as damage of the solar cell module.

  The present invention has been made in view of such circumstances, and provides a monitoring apparatus and a monitoring method for diagnosing an abnormality of a photovoltaic power generation facility with higher accuracy than conventional methods by eliminating the influence of dirt on the surface of a solar cell module. For the purpose.

In order to achieve the above object, the first invention divides the power generation amount per unit solar radiation amount calculated from the current value and voltage value of the solar cell string and the solar radiation amount incident on the solar cell string by the rated output of the solar cell string. A photovoltaic power generation monitoring device that compares the generated power generation efficiency with a reference value and determines that the solar cell string is abnormal when the power generation efficiency falls below the reference value,
In the reference value setting period, the power generation efficiency for each day calculated using data within the set number of days after the date of recording the amount of rainfall above the set value is stratified by temperature range, and the average value of power generation efficiency is obtained for each temperature range. A reference value setting unit for setting the reference value in consideration of a fluctuation range;
After the reference value setting period has elapsed, the average power generation efficiency of one day calculated by extracting the power generation data with the highest temperature band from the data within the set number of days after the date when the rainfall amount equal to or greater than the set value was recorded is the power generation efficiency. And an abnormality determination unit for comparing with the reference value in the same temperature range as the average power generation efficiency.

The second invention is based on the power generation efficiency obtained by dividing the power generation amount per unit solar radiation amount calculated from the current value and voltage value of the solar cell string and the solar radiation amount incident on the solar cell string by the rated output of the solar cell string. A photovoltaic power generation monitoring method for determining that the solar cell string is abnormal when the power generation efficiency is lower than the reference value in comparison with a value,
In the reference value setting period, the power generation efficiency for each day calculated using data within the set number of days after the date of recording the amount of rainfall above the set value is stratified by temperature range, and the average value of power generation efficiency is obtained for each temperature range. A reference value setting step for setting the reference value in consideration of a fluctuation range;
After the reference value setting period has elapsed, the average power generation efficiency of one day calculated by extracting the power generation data with the highest temperature band from the data within the set number of days after the date when the rainfall amount equal to or greater than the set value was recorded is the power generation efficiency. And an abnormality determining step for comparing with the reference value in the same temperature range as the average power generation efficiency.

  In the present invention, in order to prevent the diagnostic accuracy of the photovoltaic power generation facility from being deteriorated due to contamination on the surface of the solar cell module, the power generation efficiency and the reference value are calculated when the surface of the solar cell module is washed by a certain amount of rainfall or more. And used for diagnosis of solar power generation equipment.

  In the present invention, in order to eliminate the influence of the dirt on the surface of the solar cell module, the power generation efficiency and the reference value are calculated using data within the set number of days after the rain of a certain amount or more, and used for diagnosis of the solar power generation facility. . Thereby, abnormality of a photovoltaic power generation facility can be diagnosed with high precision compared with the past.

It is a lineblock diagram of a photovoltaic power generation system provided with a photovoltaic power generation monitoring device concerning one embodiment of the present invention. It is a flowchart which calculates a reference value. (A) is a graph of power generation amount, integrated solar radiation amount, and temperature showing an example of stable power generation, and (B) is a graph of power generation amount, integrated solar radiation amount, and temperature showing an example of unstable power generation. (A) is a solar radiation amount graph including discontinuous data areas, (B) is a solar radiation amount graph including abnormal value data of power generation efficiency, (C) is a solar radiation amount graph including data of less than 10 minutes, and (D) is It is a solar radiation amount graph which deleted defective data. It is a flowchart which judges abnormality of a solar cell string.

  Next, embodiments of the present invention will be described with reference to the accompanying drawings to provide an understanding of the present invention.

The block diagram of the photovoltaic power generation system 10 in one embodiment of the present invention is shown in FIG.
The solar power generation system 10 includes a solar power generation facility that receives sunlight to generate power, and a monitoring facility that monitors the power generation status of the solar power generation facility and diagnoses abnormality of the solar power generation facility.

The solar power generation facility includes a plurality of solar cell strings 11 each having a plurality of solar cell modules (not shown) connected in series, a junction box 12 for accumulating current generated by each solar cell string 11, and a junction box 12. A current collecting box 13 for collecting the current of the current collecting box 13 and a power conditioner 14 for collecting the current of the current collecting box 13.
As described above, the power conditioner 14 converts the direct current generated by the solar cell string 11 into an alternating current, and always maintains the power obtained from the solar cell string 11 at the maximum value. The electric power generated in the solar power generation facility is sent to the substation facility via the power conditioner 14.

The monitoring facility includes a measuring device such as a thermocouple 15 that measures the temperature of the solar cell string 11 and a solar radiation meter 16 that measures the amount of solar radiation at the site where the solar power generation facility is installed, and the current of each solar cell string 11. The storage device 17 that stores the value, voltage value, temperature, and the amount of solar radiation on the site every minute, and the solar power generation monitoring device 20 that determines whether there is an abnormality in the solar power generation facility are provided. The storage device 17 and the photovoltaic power generation monitoring device 20 are connected via the Internet 18.
A data logger or a personal computer can be used for the storage device 17, and a personal computer can be used for the photovoltaic power generation monitoring device 20.

  The solar power generation monitoring device 20 generates power by dividing the power generation amount per unit solar radiation amount calculated from the current value and voltage value of the solar cell string 11 and the solar radiation amount incident on the solar cell string 11 by the rated output of the solar cell string 11. The efficiency is compared with a reference value, and when the power generation efficiency falls below the reference value, the solar cell string 11 is determined to be abnormal.

The photovoltaic power generation monitoring device 20 includes a reference value setting unit 21 and an abnormality determination unit 22.
In the reference value setting period, the reference value setting unit 21 stratifies the power generation efficiency for each day calculated using data within the set number of days after the date when the amount of rainfall equal to or greater than the set value was recorded, In addition, the reference value is set by adding the fluctuation range to the average value of the power generation efficiency. The reference value is set for each solar cell string 11.
The abnormality determination unit 22 extracts the power generation data having the highest temperature band from the data within the set number of days after the date when the rainfall amount equal to or greater than the set value is recorded after the reference value setting period has elapsed. The efficiency is compared with a reference value in the same temperature range as the average power generation efficiency, and when the efficiency falls below the reference value, the solar cell string 11 is determined to be abnormal.

Next, the photovoltaic power generation monitoring process (method) performed on each solar cell string 11 by the photovoltaic power generation monitoring device 20 having the above configuration will be described in detail.
[Reference value setting]
A process (reference value setting step) performed by the reference value setting unit 21 will be described with reference to the flowchart of FIG.
The reference value setting period is the first year when the photovoltaic power generation system 10 starts operation.

(1) The rainfall data at the observation point closest to the site where the photovoltaic power generation facility is installed is acquired from the homepage (HP) of the Japan Meteorological Agency (ST11).
(2) Data within 4 days (set number of days) after the day when the rainfall amount of 6 mm / h (set value) or more is recorded is extracted from the storage device 17 (ST12). The extracted data is the current value, voltage value, temperature, and site solar radiation amount of the solar cell string 11 on the target day.

(3) In order to perform highly accurate abnormality diagnosis, stable power generation data with small variations is required. Therefore, it is confirmed whether the power generation data is stable by using the power generation amount graph created from the extracted data. As shown in FIG. 3 (A), when the power generation graph draws a beautiful parabola, it is regarded as stable power generation data, and as shown in FIG. 3 (B), the power generation graph changes irregularly. If so, it is considered unstable power generation data. In addition, the judgment whether it is stable electric power generation data is performed using the data of 9:00 to 15:00 considered that the solar cell string 11 whole is generating electric power normally.
When the power generation data is not stable (ST13), the process returns to ST12.

(4) When the power generation data is stable (ST13), the data of the day is stratified by the temperature band, and the data of the maximum temperature band is extracted (ST14). The maximum temperature band data includes many data with small variations in current value, voltage value, and amount of solar radiation.
In addition, the temperature zone is stratified every 5 degreeC like 30 degreeC-35 degreeC, 35 degreeC-40 degreeC, ..., 50 degreeC-55 degreeC, 55 degreeC-60 degreeC, for example.

(5) Data indicating an abnormal value of power generation efficiency due to a decrease in the amount of solar radiation and discontinuous data are excluded from the extracted data (ST15).
A region surrounded by a frame in FIG. 4A shows a region where the temperature of the solar cell string 11 is lowered and the data is discontinuous with a significant decrease in the amount of solar radiation.
The region surrounded by the frame in FIG. 4B is a region where the power generation efficiency shows an abnormal value due to a difference between the solar radiation amount and the current value due to a significant decrease in the solar radiation amount.
The area surrounded by the frame in FIG. 4C is an area that has become data less than 10 minutes by deleting discontinuous data and data indicating an abnormal value of power generation efficiency.
FIG. 4D is a solar radiation amount graph from which defective data is deleted.

(6) If the number of data is less than 50 (ST16), the process returns to ST12.
(7) When the number of data is 50 or more (ST16), the power generation efficiency is calculated from the data (ST17), and the calculated power generation efficiency is stored in the corresponding temperature band (ST18). For example, in winter power generation efficiency, the maximum temperature range is data in the vicinity of 30 ° C. to 35 ° C., and in summer power generation efficiency, the maximum temperature range is in the range of 55 ° C. to 60 ° C.

(8) If one year, which is the reference value setting period, has not elapsed (ST19), the process returns to ST11 and the same processing is performed for other months and days.
(9) When one year, which is the reference value setting period, has passed (ST19), the average value is calculated for the power generation efficiency stored for each temperature band, and the fluctuation range is added to the average value for each temperature band. A reference value is set (ST20). The fluctuation range is −3σ. Where σ is the standard deviation of power generation efficiency.

[Abnormal judgment]
A process (abnormality determination step) performed by the abnormality determination unit 22 after the passage of the reference value setting period of one year will be described with reference to the flowchart of FIG.
Note that the process from the acquisition of weather data from the Japan Meteorological Agency HP (ST21) to the number of data ≧ 50 (ST26) is the same as ST11 to ST16 in the setting of the reference value, and the description thereof will be omitted.

(1) When the number of data is 50 or more (ST26), an average value of power generation efficiency is calculated for the data (ST27).
(2) The calculated daily average power generation efficiency is compared with a reference value in the same temperature range as the average power generation efficiency (ST28). If the average power generation efficiency is less than the reference value, the solar cell string 11 that is less than the reference value is abnormal. Displayed as being present (ST29), and if it is equal to or greater than the reference value, the process is terminated as being normal (ST30).

  Although one embodiment of the present invention has been described above, the present invention is not limited to the configuration described in the above-described embodiment, and is within the scope of matters described in the claims. Other possible embodiments and modifications are also included. For example, in the above embodiment, the set value is 6 mm / h of rainfall, the set number of days is 4 days, and the fluctuation range of the reference value is −3σ. Of course, the value is not limited to these values. The amount may be 4 mm / h to 8 mm / h, the set number of days may be 2 to 6 days, and the fluctuation range may be −2σ to −3σ.

10: Solar power generation system, 11: Solar cell string, 12: Junction box, 13: Current collection box, 14: Power conditioner, 15: Thermocouple, 16: Solar radiation meter, 17: Storage device, 18: Internet, 20: Photovoltaic power generation monitoring device, 21: reference value setting unit, 22: abnormality determination unit

Claims (2)

The power generation efficiency obtained by dividing the power generation amount per unit solar radiation amount calculated from the current value and voltage value of the solar cell string and the solar radiation amount incident on the solar cell string by the rated output of the solar cell string is compared with a reference value, and the power generation efficiency Is a photovoltaic power generation monitoring device that determines that the solar cell string is abnormal when the reference value falls below the reference value,
In the reference value setting period, the power generation efficiency for each day calculated using data within the set number of days after the date of recording the amount of rainfall above the set value is stratified by temperature range, and the average value of power generation efficiency is obtained for each temperature range. A reference value setting unit for setting the reference value in consideration of a fluctuation range;
After the reference value setting period has elapsed, the average power generation efficiency of one day calculated by extracting the power generation data with the highest temperature band from the data within the set number of days after the date when the rainfall amount equal to or greater than the set value was recorded is the power generation efficiency. A solar power generation monitoring apparatus comprising: an abnormality determination unit that compares the average power generation efficiency with the reference value in the same temperature range as the average power generation efficiency. The power generation efficiency obtained by dividing the power generation amount per unit solar radiation amount calculated from the current value and voltage value of the solar cell string and the solar radiation amount incident on the solar cell string by the rated output of the solar cell string is compared with a reference value, and the power generation efficiency Is a photovoltaic power generation monitoring method for determining that the solar cell string is abnormal when the value falls below the reference value,
In the reference value setting period, the power generation efficiency for each day calculated using data within the set number of days after the date of recording the amount of rainfall above the set value is stratified by temperature range, and the average value of power generation efficiency is obtained for each temperature range. A reference value setting step for setting the reference value in consideration of a fluctuation range;
After the reference value setting period has elapsed, the average power generation efficiency of one day calculated by extracting the power generation data with the highest temperature band from the data within the set number of days after the date when the rainfall amount equal to or greater than the set value was recorded is the power generation efficiency. And an abnormality determination step of comparing with the reference value in the same temperature band as the average power generation efficiency.

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