JP5462821B2 - Solar cell abnormality determination device and solar cell abnormality determination method - Google Patents

Description

  The present invention relates to a solar cell abnormality determination device and a solar cell abnormality determination method for determining abnormality of a solar cell.

The current-voltage characteristics and power-voltage characteristics of the solar cell will be described using FIGS. 7A, 7B, and 7C, respectively.
The current-voltage characteristic shown in FIG. 7A is a characteristic when the solar radiation intensity is the same at all locations on the surface of the solar cell. In FIG. 7A, the vertical axis represents the output current of the solar cell, and the horizontal axis represents the output voltage. As shown in FIG. 7A, the output current (vertical axis) of the solar cell suddenly decreases from a substantially constant state around the open circuit voltage value V _oc when the output voltage (horizontal axis) is increased. It changes along the curve. Therefore, since the output power of the solar cell is represented by the product of the output current and the output voltage, as shown in FIG. 7B, the output voltage changes so as to have a peak (maximum power point). To do.

Therefore, in order to take out the maximum output power P _m (see FIG. 7B) from the solar cell, the output voltage is controlled. This control is called maximum power point tracking control (MPPT (Maximum Power Point Tracking) control). Here, as shown in FIG. 7 (a), the output voltage value at the maximum output power P _m, referred to as the maximum output operation voltage V _Pm, the output current value when the maximum output power P _m, maximum The output operating current value I _Pm is called, the output current value when the output voltage is 0 volt is called the short-circuit current value I _SC, and the output voltage value when the output current is 0 ampere is called the open circuit voltage value V _oc .

  By the way, when the solar cell surface is shaded by an obstacle around the solar cell, or when fallen leaves or birds and animals droppings adhere to the solar cell surface (when a partial shadow occurs), solar radiation on the solar cell surface Since the intensity is biased, the current-voltage characteristic is significantly different from the current-voltage characteristic shown in FIG. 7A, for example, as shown in FIG.

  Patent Document 1 describes a solar power generation system that determines that a solar cell is abnormal when a failure occurs in a solar cell or when a partial shadow occurs. This photovoltaic power generation system stores current voltage characteristics that are standard for solar cells in advance, and determines whether or not there is an abnormality by comparing the measured current voltage characteristics with the standard current voltage characteristics. .

JP 2006-201827 A (refer to paragraph 0038 in particular)

  However, in Patent Literature 1, if the standard current-voltage characteristics stored in advance in the photovoltaic power generation system are different from each other in the module configuration of the solar cell, it is necessary to store the standard current-voltage characteristics used in the module configuration. There is a problem that the labor is complicated. In addition, the stored standard current-voltage characteristics may not accurately represent the current-voltage characteristics of individual solar cells assembled at the actual installation site and the surrounding environment. In addition, even if the current-voltage characteristics of the solar cell are different from the stored standard current-voltage characteristics due to deterioration over time, there is a problem that it is not possible to automatically follow the change in the current-voltage characteristics.

  Therefore, an object of the present invention is to provide a technique for easily acquiring current-voltage characteristics that serve as a reference for determining an abnormality of a solar cell and determining an abnormality of the solar cell.

ただし、Ｉは、太陽電池の出力電流、Ｖは、太陽電池の出力電圧、expは、指数関数を表し、lnは、自然対数を表す。
In order to solve the above-mentioned problem, the solar cell abnormality determination device determines the maximum output operating voltage when the short-circuit current value I _SC , the open-circuit voltage value V _oc , and the maximum output power of the solar cell from the measured current-voltage characteristics of the solar cell. The value V _Pm and the maximum output operating current value I _Pm are acquired, and these values are applied to the following equation (2) to calculate the coefficients a and b. The calculated coefficients a and b are expressed by the following equation (1) To generate a reference current-voltage characteristic represented by equation (1). Next, the solar cell abnormality determination device determines whether there is an abnormality in the solar cell by comparing the current-voltage characteristic acquired by actual measurement with the reference current-voltage characteristic.

Where I is the output current of the solar cell, V is the output voltage of the solar cell, exp is an exponential function, and ln is the natural logarithm.

  ADVANTAGE OF THE INVENTION According to this invention, the technique which acquires the current voltage characteristic used as the reference | standard for determining the abnormality of a solar cell easily, and determines the abnormality of a solar cell can be provided.

It is a figure which shows the structural example of the solar cell system in this embodiment, and the functional example of a solar cell abnormality determination apparatus. It is a figure which shows the example of a processing flow of a solar cell abnormality determination apparatus. It is a figure which shows the case where the parameter | index of abnormality determination is an area ratio, (a) represents the case without a partial shadow, (b) represents the case with a partial shadow. It is a figure which shows the case where the parameter | index of abnormality determination is the average value of the difference of measured current voltage characteristic and a reference current voltage characteristic, (a) represents the case without a partial shadow, (b) represents the case with a partial shadow. Represent. It is a figure which shows the case where the parameter | index of abnormality determination is the maximum difference value of measured current voltage characteristic and a reference current voltage characteristic, (a) represents the case where there is no partial shadow, (b) represents the case where there is a partial shadow. . The abnormality determination index is a diagram showing a case where the current value of the measured current-voltage characteristic is an area in a range smaller than the current value of the reference current-voltage characteristic, where (a) shows a case where there is no partial shadow, and (b) shows This represents the case with partial shadows. It is a figure for demonstrating the characteristic of a solar cell, and the prior art of MPPT control, (a) represents the current voltage characteristic of a solar cell, (b) represents the power voltage characteristic of a solar cell, (c) is a partial. It represents the current-voltage characteristics when a shadow occurs.

  A mode for carrying out the invention (hereinafter referred to as “embodiment”) will be described in detail with reference to the drawings as appropriate.

(Solar cell system)
A configuration example of the solar cell system 1 will be described with reference to FIG.
As shown in FIG. 1, the solar cell system 1 includes a solar cell control device 10, a solar cell 13, a sensor 14, and a solar cell abnormality determination device 30.

  The solar cell control device 10 includes a power conversion unit 12, converts the DC power extracted from the solar cell 13, and outputs it to a load. Further, the solar cell control device 10 includes a solar cell characteristic acquisition unit 11, and acquires a current value and a voltage value from a short circuit state to an open state of the solar cell 13 via the sensor 14. Then, the solar cell control device 10 transmits the actually measured current value and voltage value to the solar cell abnormality determination device 30.

(Solar cell abnormality determination device)
Next, a function example of the solar cell abnormality determination device 30 will be described with reference to FIG.
The solar cell abnormality determination device 30 includes at least a processing unit 20, a display unit 27, a communication unit 28, and a storage unit 29. The solar cell abnormality determination device 30 determines whether or not a partial shadow is generated in the solar cell 13. The partial shadow is a shadow caused by an obstacle existing around the solar cell 13 or a shadow caused by a fallen leaf, bird droppings, or the like adhering to the surface of the solar cell 13. In the present embodiment, it is determined that a partial shadow is generated in the solar cell 13 as an abnormality of the solar cell 13.

  The processing unit 20 is configured by a CPU (Central Processing Unit) and a main memory (not shown), and develops an application program stored in the storage unit 29 in the main memory, and a current value voltage value acquisition unit 21 and a power calculation unit 22. The reference current-voltage characteristic calculation unit 23 and the determination unit 24 are embodied.

  The current value voltage value acquisition unit 21 acquires an actually measured current value and voltage value (hereinafter referred to as an actually measured current voltage characteristic) from the solar cell characteristic acquisition unit 11 of the solar cell control device 10.

The power calculation unit 22 calculates a power value using the current value and the voltage value acquired by the current value voltage value acquisition unit 21, and acquires a maximum output power value that is the maximum among the calculated power values. The power calculation unit 22 obtains a maximum output operating voltage value V _Pm and a maximum output operating current value I _Pm indicating the voltage value and the current value at the maximum output power value, respectively. Then, the power calculator 22 transmits the short-circuit current value I _SC , the open-circuit voltage value V _oc , the maximum output operating voltage value V _Pm , and the maximum output operating current value I _Pm to the reference current-voltage characteristic calculator 23.

The reference current-voltage characteristic calculation unit 23 applies the short-circuit current value I _SC , the open-circuit voltage value V _oc , the maximum output operating voltage value V _Pm , and the maximum output operating current value I _Pm to the following equation (2) to obtain a coefficient a , B are calculated, and the calculated coefficients a, b are applied to the following equation (1) to generate a reference current-voltage characteristic (hereinafter referred to as a reference current-voltage characteristic) represented by equation (1). To do. Here, Formula (1) and Formula (2) are re-displayed. The derivation of the expressions (1) and (2) will be described later.

ただし、Ｉは、出力電流、Ｖは、出力電圧、expは、指数関数を表し、lnは、自然対数を表す。

However, I represents an output current, V represents an output voltage, exp represents an exponential function, and ln represents a natural logarithm.

  The determination unit 24 determines whether or not the solar cell is abnormal by comparing the measured current voltage characteristic and the reference current voltage characteristic. The determination unit 24 displays one or both of displaying the determination result on the display unit 27 and outputting the determination result to the terminal via the communication unit 28. The determination method will be described later.

The display unit 27 is a liquid crystal display or the like and displays a determination result.
The communication unit 28 is an interface for transmitting and receiving information to and from a terminal (for example, a personal computer or a portable terminal) used by a maintainer or administrator of the solar cell system 1. The communication unit 28 transmits and receives information by wire or wireless.
The storage unit 29 stores application programs, processing results of the processing unit 20, and the like.

(Processing flow of solar cell abnormality determination device)
Next, the processing flow of the solar cell abnormality determination device 30 will be described with reference to FIG. 2 (see FIG. 1 as appropriate).
In step S401, the current value voltage value acquisition unit 21 acquires the measured current value and voltage value (measured current voltage characteristic).

In step S402, the power calculation unit 22 calculates a power value using the current value and the voltage value acquired by the current value voltage value acquisition unit 21.
In step S403, the power calculation unit 22 acquires the maximum output power value that is the maximum among the calculated power values.
In step S404, the power calculation unit 22 acquires a maximum output operating voltage value V _Pm and a maximum output operating current value I _Pm indicating the voltage value and the current value when the acquired maximum output power value is obtained. Then, the power calculator 22 transmits the short-circuit current value I _SC , the open-circuit voltage value V _oc , the maximum output operating voltage value V _Pm , and the maximum output operating current value I _Pm to the reference current-voltage characteristic calculator 23.

In step S405, the reference current-voltage characteristic calculator 23 calculates the short-circuit current value I _SC , the open-circuit voltage value V _oc , the maximum output operating voltage value V _Pm , and the maximum output operating current value I _Pm received from the power calculator 22. The coefficients a and b are calculated by applying to the equation (2), and the calculated coefficients a and b are applied to the equation (1) to generate the reference current voltage characteristic represented by the equation (1). .

In step S406, the determination unit 24 determines whether or not the solar cell is abnormal by comparing the measured current voltage characteristic and the reference current voltage characteristic.
In step S <b> 407, the determination unit 24 executes one or both of displaying the determination result on the display unit 27 and transmitting the determination result to the terminal via the communication unit 28.

  The solar cell abnormality determination device 30 executes the processes of steps S401 to S407 when receiving a predetermined cycle or an instruction from a maintenance person or an administrator.

  Next, four examples of the determination method for determining whether or not the solar cell 13 (see FIG. 1) is abnormal will be described with reference to FIGS.

(First determination method)
As shown in FIG. 3, the determination unit 24 (see FIG. 1) performs determination using an area ratio calculated by dividing the area of the measured current-voltage characteristic by the area of the reference current-voltage characteristic as a determination index. . Here, the area is a value obtained by integrating the voltage value with respect to the current value as an integration variable.
FIG. 3A shows a case where there is no partial shadow, and the reference current voltage characteristic (solid line) and the measured current voltage characteristic (broken line) show a similar tendency. Therefore, the area ratio is a value close to 1.

On the other hand, in the case where there is a partial shadow shown in FIG. 3B, the current value of the measured current-voltage characteristic is significantly lower than the reference current-voltage characteristic in the region where the voltage value is large due to the influence of the shadow. Accordingly, the area of the measured current-voltage characteristic shown in FIG. 3B is smaller than the area of the measured current-voltage characteristic shown in FIG. That is, the area ratio is smaller than 1.
Therefore, the determination unit 24 determines that the solar cell 13 is abnormal when the area ratio is less than the first threshold. Note that the first threshold value is stored in the storage unit 29 (see FIG. 1).

(Second determination method)
As shown in FIG. 4, the determination unit 24 (see FIG. 1) performs determination using an average value of the difference between the measured current voltage characteristic and the reference current voltage characteristic as a determination index.
FIG. 4A shows a case where there is no partial shadow, and the reference current voltage characteristics and the measured current voltage characteristics show a similar tendency. Here, the difference between the measured current voltage characteristic and the reference current voltage characteristic is calculated by subtracting the current values of the reference current voltage characteristic and the measured current voltage characteristic when the voltage values are equal when calculating the current value. Value. When calculating the difference between the measured current voltage characteristic and the reference current voltage characteristic for the voltage value, a value calculated by subtracting the voltage values of the reference current voltage characteristic and the measured current voltage characteristic when the current values are equal. It is. In FIG. 4A, the average value of the difference between the measured current-voltage characteristic and the reference current-voltage characteristic is a small value. In addition, you may take the average value of the absolute value of a difference instead of the average value of a difference.

On the other hand, in the case of the partial shadow shown in FIG. 4B, the current value of the measured current-voltage characteristic is greatly reduced from the reference current-voltage characteristic in the region where the voltage value is large due to the influence of the shadow. For this reason, the average value of the difference between the measured current-voltage characteristic and the reference current-voltage characteristic shown in FIG. 4B is larger than that in the case of FIG.
Therefore, the determination unit 24 determines whether the average value of the difference with respect to the voltage value is larger than the second threshold value, or when the average value of the difference with respect to the current value is larger than the third threshold value. 13 abnormalities are determined. The second and third threshold values are stored in the storage unit 29 (see FIG. 1).

(Third determination method)
As shown in FIG. 5, the determination unit 24 (see FIG. 1) performs determination using the maximum difference value between the measured current voltage characteristic and the reference current voltage characteristic as a determination index.
FIG. 5A shows the case where there is no partial shadow, and the reference current voltage characteristics and the measured current voltage characteristics show a similar tendency. Here, when calculating the current value, the maximum difference value between the measured current voltage characteristic and the reference current voltage characteristic is obtained by subtracting the current values of the reference current voltage characteristic and the measured current voltage characteristic when the voltage values are equal. It is the maximum value among the calculated differences. In addition, when calculating the maximum difference value between the measured current voltage characteristic and the reference current voltage characteristic for the voltage value, the voltage values of the reference current voltage characteristic and the measured current voltage characteristic when the current values are equal are subtracted from each other. It is the largest value among the differences. In FIG. 5A, the maximum difference value between the measured current-voltage characteristic and the reference current-voltage characteristic is a small value.

On the other hand, in the case where there is a partial shadow shown in FIG. 5B, the current value of the measured current-voltage characteristic is significantly lower than the reference current-voltage characteristic in the region where the voltage value is large due to the influence of the shadow. Therefore, the maximum difference value between the measured current-voltage characteristic and the reference current-voltage characteristic shown in FIG. 5B is larger than that in the case of FIG.
Therefore, when the maximum difference value of the voltage is larger than the fourth threshold value between the actually measured current voltage characteristic and the reference current voltage characteristic, the determination unit 24 has a smaller current difference value than the fifth threshold value. In either or both cases, it is determined that the solar cell 13 is abnormal. The fourth and fifth threshold values are stored in the storage unit 29 (see FIG. 1).

(Fourth determination method)
As shown in FIG. 6, the determination unit 24 (see FIG. 1) performs determination using an area in a range where the current value of the measured current-voltage characteristic is smaller than the current value of the reference current-voltage characteristic as a determination index. Here, when the current value of the measured current-voltage characteristic is smaller than the current value of the reference current-voltage characteristic, the area is the voltage value of the difference obtained by subtracting the current value of the measured current-voltage characteristic from the current value of the reference current-voltage characteristic. It is the value integrated as an integration variable.
FIG. 6A shows a case where there is no partial shadow, and the reference current voltage characteristics and the measured current voltage characteristics show a similar tendency. The area where the current value of the measured current-voltage characteristic is smaller than the current value of the reference current-voltage characteristic is a small value.

On the other hand, in the case of the partial shadow shown in FIG. 6B, the current value of the measured current-voltage characteristic is significantly lower than the reference current-voltage characteristic in the region where the voltage value is large due to the influence of the shadow. Therefore, the area in the range where the current value of the measured current-voltage characteristic shown in FIG. 6B is smaller than the current value of the reference current-voltage characteristic is larger than that in the case of FIG.
Therefore, the determination unit 24 determines that the solar cell 13 is abnormal when the area in the range where the current value of the measured current-voltage characteristic is smaller than the current value of the reference current-voltage characteristic is larger than the sixth threshold value. The sixth threshold value is stored in the storage unit 29 (see FIG. 1).

  In addition, the 1st-4th determination method may be used independently, or may be used in multiple combinations. In the case of a plurality of combinations, the determination unit 24 (see FIG. 1) performs a size comparison with the threshold value for each combined determination index, and determines that all the combined determination indices are abnormal for the solar cell 13. In this case, it may be determined that the solar cell 13 is abnormal. Or the determination part 24 (refer FIG. 1) may determine with the abnormality of the solar cell 13, when it determines with the abnormality of the solar cell 13 in one of the combined determination indicators.

(Derivation of Formula (1) and Formula (2))
Here, the derivation | leading-out of said Formula (1) and Formula (2) is demonstrated.
The theoretical formula of the current-voltage characteristic of the solar cell 13 is represented by the following formula (A).

ただし、Ｉは出力電流、Ｉ_SCは短絡電流、Ｉ₀は逆飽和電流、ｅは素電荷、Ｖは出力電圧、ｎは理想因子、ｋはボルツマン定数、Ｔは絶対温度である。

Where I is an output current, I _SC is a short-circuit current, I ₀ is a reverse saturation current, e is an elementary charge, V is an output voltage, n is an ideal factor, k is a Boltzmann constant, and T is an absolute temperature.

When the constants and the like of the formula (A) are combined into the coefficients a and b, they are represented by the following formula (B).

When V = V _oc , since I = 0, the following formula (C) is obtained.

Further, when V = V _Pm , since I = I _Pm , the following equation (D) is obtained.

Substituting a in formula (C) into formula (D) yields formula (E) below.

Since exp (b · V _Pm ) >> 1 and exp (b · V _OC ) >> 1, the following approximation holds.

Therefore, the following formula (G) is obtained.

By taking the logarithm of both sides of the formula (G), b can be derived.

The following formulas (1) and (2) are derived from the formulas (B), (C), and (H). Here, Formula (1) and Formula (2) are re-displayed.

As described above, the solar cell abnormality determination device 30 according to the present embodiment, when determining the abnormality of the solar cell 13, uses the measured reference current voltage characteristics as a reference for the determination, the short-circuit current value I _SC of the actually measured solar cell 13, and the open-circuit voltage. The value V _oc , the maximum output operating voltage value V _Pm , and the maximum output operating current value I _Pm can be calculated using the equations (1) and (2). Therefore, even when the current-voltage characteristic of the solar cell 13 changes due to aging or the like, the current-voltage characteristic serving as a reference for determining the abnormality of the solar cell 13 can be easily calculated. Moreover, the abnormality of the solar cell 13 due to the partial shadow can be easily determined by comparing the calculated reference current voltage characteristic with the actually measured current voltage characteristic obtained by the actual measurement.

  In addition, when it is determined that the solar cell 13 is abnormal, in order to distinguish whether the abnormality is due to a failure or dirt that must be removed, or a temporary partial shadow, the duration of the abnormality is determined. May be determined by whether or not exceeds a predetermined threshold.

DESCRIPTION OF SYMBOLS 13 Solar cell 20 Processing part 21 Current value voltage value acquisition part 22 Power calculation part 23 Reference | standard current voltage characteristic calculation part 24 Determination part 27 Display part 28 Communication part 29 Memory | storage part 30 Solar cell abnormality determination apparatus

Claims (8)

A solar cell abnormality determination device for determining abnormality of a solar cell,
A current value voltage value acquisition unit for acquiring measured current voltage characteristics of the current value and voltage value of the solar cell;
A power calculator that calculates a power value using the measured current-voltage characteristics and acquires a voltage value and a current value when the maximum power value is obtained among the calculated power values;
Using the voltage value and current value when the maximum power value is reached, the short-circuit current value when the solar cell is short-circuited, and the open-circuit voltage value when the solar cell is open, A reference current-voltage characteristic calculation unit for calculating a reference current-voltage characteristic serving as a reference for determining
A solar cell abnormality determination device, comprising: a determination unit that compares the measured current-voltage characteristic with the reference current-voltage characteristic and determines whether there is an abnormality with a predetermined index. The reference current-voltage characteristic calculation unit includes:
The voltage value V _Pm and current value I _{Pm at the} maximum power value, the short-circuit current value I _SC, and the open-circuit voltage value V _oc are applied to the following formulas (1) and (2). The solar cell abnormality determination device according to claim 1, wherein the reference current voltage characteristic is calculated.

Where I is the output current of the solar cell, V is the output voltage of the solar cell, exp is an exponential function, and ln is the natural logarithm. The predetermined indicator is
The area ratio calculated by dividing the area of the measured current voltage characteristic by the area of the reference current voltage characteristic, the average value of the difference between the measured current voltage characteristic and the reference current voltage characteristic, the measured current voltage characteristic and the reference The maximum difference value from the current-voltage characteristics, the current value of the measured current-voltage characteristics is any one of the areas in a range smaller than the current value of the reference current-voltage characteristics,
The determination unit
3. The solar cell abnormality according to claim 1, wherein the value of the predetermined index is compared with a predetermined threshold value, and the presence or absence of abnormality is determined based on the comparison result. Judgment device. The determination unit
In comparison with the threshold value,
When the area ratio calculated by dividing the area of the measured current-voltage characteristic by the area of the reference current-voltage characteristic is smaller than a first threshold, the difference between the measured current-voltage characteristic and the reference current-voltage characteristic is a difference in voltage value If the average value of the difference between the measured current voltage characteristics and the reference current voltage characteristics is greater than the third threshold value, the measured current voltage characteristics and the reference When the maximum difference value of current from the current-voltage characteristic is larger than a fourth threshold value, when the maximum difference value of voltage between the measured current-voltage characteristic and the reference current-voltage characteristic is larger than a fifth threshold value, the measured current voltage 4. The method according to claim 3, wherein when the area of the characteristic current value smaller than the current value of the reference current voltage characteristic is larger than a sixth threshold, it is determined that there is an abnormality in any of the cases. Solar cell abnormality determination device. A solar cell abnormality determination method in a solar cell abnormality determination device for determining abnormality of a solar cell,
The solar cell abnormality determination device is
Obtaining measured current-voltage characteristics of the current value and voltage value of the solar cell;
Using the measured current-voltage characteristics, calculating a power value, and obtaining a voltage value and a current value when the maximum power value is obtained among the calculated power values;
Using the voltage value and current value when the maximum power value is reached, the short-circuit current value when the solar cell is short-circuited, and the open-circuit voltage value when the solar cell is open, A reference current-voltage characteristic calculation step for calculating a reference current-voltage characteristic serving as a reference for determining
A method for determining an abnormality in a solar cell, comprising: comparing the measured current-voltage characteristic with the reference current-voltage characteristic, and determining a presence or absence of abnormality with a predetermined index. The solar cell abnormality determination device is
In the reference current-voltage characteristic calculation step,
Applied voltage value V _Pm when the said maximum power value, and the current value I _Pm, and the short-circuit current value I _SC, the open voltage V _oc and, below following formula (1), the equation (2) The solar cell abnormality determination method according to claim 5, wherein the reference current voltage characteristic is calculated.

Where I is the output current of the solar cell, V is the output voltage of the solar cell, exp is an exponential function, and ln is the natural logarithm. The predetermined indicator is
The area ratio calculated by dividing the area of the measured current voltage characteristic by the area of the reference current voltage characteristic, the average value of the difference between the measured current voltage characteristic and the reference current voltage characteristic, the measured current voltage characteristic and the reference The maximum difference value from the current-voltage characteristics, the current value of the measured current-voltage characteristics is any one of the areas in a range smaller than the current value of the reference current-voltage characteristics,
The solar cell abnormality determination device is
In the determination step,
The solar cell abnormality according to claim 5 or 6, wherein the value of the predetermined index is compared with a predetermined threshold value, and the presence or absence of abnormality is determined based on the comparison result. Judgment method. The solar cell abnormality determination device is
In the determination step, in the comparison with the threshold value,
When the area ratio calculated by dividing the area of the measured current-voltage characteristic by the area of the reference current-voltage characteristic is smaller than a first threshold, the difference between the measured current-voltage characteristic and the reference current-voltage characteristic is a difference in voltage value If the average value of the difference between the measured current voltage characteristics and the reference current voltage characteristics is greater than the third threshold value, the measured current voltage characteristics and the reference When the maximum difference value of current from the current-voltage characteristic is larger than a fourth threshold value, when the maximum difference value of voltage between the measured current-voltage characteristic and the reference current-voltage characteristic is larger than a fifth threshold value, the measured current voltage 8. The method according to claim 7, wherein an abnormality is determined in any of the cases where the area of the range in which the current value of the characteristic is smaller than the current value of the reference current-voltage characteristic is larger than the sixth threshold value. Solar cell abnormality determination method.

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