KR101813672B1 - Apparatus for Degradation Diagnosis of Photovoltaic Module - Google Patents

Abstract

The present invention discloses a deterioration diagnosis apparatus for a solar cell module. The deterioration diagnosis apparatus provided in each connection module connected to each PV string group including a plurality of solar cell modules in the solar power generation system according to an aspect of the present invention is characterized in that the deterioration diagnosis apparatus includes solar energy detection part; And when the solar radiation amount exceeds a preset threshold value every predetermined period, the mode is switched to the degradation diagnosis mode, and the current open voltage and current short circuit current of each solar cell module in each PV string group are measured, The module voltage and current variation of each PV string group are calculated using the difference between the initial open-circuit voltage of the module and the current open-circuit voltage, the initial short-circuit current and the current short-circuit current difference, If the standard deviation of the current variation exceeds the predetermined first and second reference values, and if the standard deviation is less than or equal to the predetermined first and second reference values, corresponding to the module voltage and current variation of each PV string group And at least one connection half module including a microprocessor for transmitting the module deterioration degree.

Description

[0001] Apparatus for Degradation Diagnosis of Photovoltaic Module [

The present invention relates to a monitoring technology for a solar cell module, and more particularly, to a deterioration diagnosis device for a solar cell module capable of diagnosing the deterioration of the solar cell module.

Recently, as interest in environmental conservation has increased due to global warming, researches on the technology for suppressing CO2 emission are actively being carried out. In the field of electric energy production, the need for renewable energy such as solar power generation, tidal power, and wind power is increasing.

As part of that, the solar power plant transforms the electricity (DC) generated by the solar module by the solar module from the inverter to the direct current (AC), boosts it from the AC switchboard and transmits it to the power system through the power distribution system.

These solar power plants are actively installed on large scale or small scale in domestic as well as overseas.

However, it is difficult for the user to confirm the abnormality by hand because the solar power plant is installed at a place where the user can not access the roof, which is a position where the sunlight can be more contacted.

Accordingly, the solar power plant has a monitoring means capable of checking whether it is abnormal such as a camera, thereby monitoring an abnormality of the solar power plant.

Korean Patent No. 10-1223502 (registered on January 11, 2013)

SUMMARY OF THE INVENTION It is an object of the present invention to provide a deterioration diagnostic apparatus for a solar cell module capable of diagnosing deterioration of a solar cell module for each PV string group.

The objects of the present invention are not limited to the above-mentioned objects, and other objects not mentioned can be clearly understood by those skilled in the art from the following description.

,

(수학식 1)을 통해 산출할 수 있으며,

및

는 10회 산출된 각 PV 스트링 그룹의 모듈 변이도의 평균치라고 할 때, 각 프로세서는 10회 만큼 PV 스트링 그룹의 모듈 변이도를 각기 산출한 후, 각 모듈 변이도의 표준편차 sV, sI를,

,

(수학식 2)를 통해 산출할 수 있으며, 각 프로세서는, 기설정된 주기마다 상기 일사량이 기설정된 임계치를 초과하는 시점에, 열화 진단 모드로 전환되어, 각 릴레이를 제어하여 상기 각 PV 스트링 그룹의 출력을 개방 또는 단락한 상태에서 각 계측 수단에 의해 상기 각 PV 스트링 그룹에 포함된 각 PV 모듈의 현 개방 전압 및 현 단락 전류를 측정하고, 상기 각 PV 모듈 내 태양 전지 셀의 개수, 상기 각 PV 모듈의 표면적, 상기 각 PV 모듈의 전압 온도 계수 및 상기 각 PV 모듈의 전류 온도 계수는, 상기 각 PV 스트링 그룹에 포함된 각 PV 모듈의 제조사에서 제공된 것이며, 상기 기준 온도와 상기 기준 일사량은, 상기 표준 시험 환경의 온도와 일사량이다. The apparatus for diagnosing deterioration of a solar cell module according to the present invention comprises a solar radiation amount sensing unit for measuring a solar radiation amount in an installation environment of a solar cell system and a plurality of PV strings connected to each PV string group of one solar cell array of the solar battery system, Wherein each PV string group comprises a plurality of PV modules, Vocm is the current open voltage of the solar cell module in the PV string group, Iscm is the current short circuit current, Voc is the initial open voltage of the connection half module, Isc is the initial short circuit current of the connection half module, Tref is the reference temperature of the connection half module, Tm is the currently measured connection half module temperature, S is the surface of the connection half module N is the number of solar cells in the connection half module, a is the current temperature coefficient for applying the change in characteristic of the short circuit current according to the connection half module temperature, b is (I) and dI (i), respectively, if the voltage is a voltage temperature coefficient for applying a change in the characteristics of the open-

,

(1), < / RTI >

And

Is the average value of the module variations of each PV string group calculated ten times, each processor calculates each module variation of the PV string group ten times, and then calculates standard deviation sV, sI of each module variation,

,

(2), and each processor switches to the deterioration diagnosis mode at a point of time when the irradiation dose exceeds a predetermined threshold value every predetermined period, and controls each relay so that the PV string group Measuring the current open-circuit voltage and the current short-circuit current of each PV module included in each PV string group by each measurement means in a state where the output is open or shorted, and the number of solar cells in each PV module, Wherein the surface temperature of the module, the voltage temperature coefficient of each PV module, and the current temperature coefficient of each PV module are provided by the manufacturer of each PV module included in each PV string group, The temperature and the solar radiation of the standard test environment.

Each relay includes a first relay connected in series to one polarity of the output of each PV string group and a second relay connected in parallel to the polarity of the output of each PV string group, Wherein each of the measurement means includes a voltmeter and an ammeter for measuring a current and a voltage at the output of each of the PV string groups, and each of the processors is operable, by the voltmeter Measuring the open-circuit voltage of each PV string group, measuring the short-circuit current of each PV string group by the ammeter in a state where the first relay is opened and the second relay is short-circuited, The open-circuit voltage and the short-circuit current can be calculated by dividing the number of the plurality of PV modules included in each PV string group by the open-circuit voltage and the short-circuit current.

Each of the plurality of connection module units may further include a temperature sensing unit for sensing a current temperature of each of the PV modules included in the PV string group.

At least one of the processors may warn an occurrence of an abnormality if the radiation dose does not exceed the threshold from the present cycle to the next cycle.

According to the present invention, deterioration of the solar cell module can be diagnosed for each PV string group.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram of a photovoltaic power generation system equipped with a degradation diagnostic apparatus according to an embodiment of the present invention; FIG.
FIG. 2 is a detailed view of a master connection module and a slave connection module according to an embodiment of the present invention; FIG.
3A and 3B are views showing relay control in a deterioration diagnosis mode according to an embodiment of the present invention;
3C is a diagram illustrating relay control in a monitoring mode according to an embodiment of the present invention.
4 is a flowchart illustrating a method for diagnosing deterioration of a solar cell module according to an embodiment of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS The above and other objects, advantages and features of the present invention and methods of achieving them will be apparent from the following detailed description of embodiments thereof taken in conjunction with the accompanying drawings. The present invention may, however, be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Is provided to fully convey the scope of the invention to those skilled in the art, and the invention is only defined by the scope of the claims. It is to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. In the present specification, the singular form includes plural forms unless otherwise specified in the specification. As used herein, the terms " comprises, " and / or "comprising" refer to the presence or absence of one or more other components, steps, operations, and / Or additions.

Embodiments of the present invention will now be described in detail with reference to the accompanying drawings. FIG. 1 is a block diagram of a photovoltaic power generation system equipped with a degradation diagnosis apparatus according to an embodiment of the present invention. FIG. 2 is a block diagram of a master connection module and a slave connection module according to an embodiment of the present invention. FIG.

1, a photovoltaic power generation system 10 including a deterioration diagnosis apparatus according to an embodiment of the present invention includes a solar radiation amount sensing unit 110, at least one temperature sensing unit 120, Modules 130_1 and 2, respectively. Here, the photovoltaic system 10 comprises a single PV array comprising a plurality of PV strings.

The solar radiation amount sensing unit 110 measures the solar radiation amount of the environment in which the solar battery module is installed. At this time, the irradiation amount sensing unit 110 may be provided in each PV string group or only one solar light generation system 10 may be provided.

The temperature sensing unit 120 is provided in each PV string group in which one PV string or a plurality of PV strings are connected in parallel to measure the module temperature of each PV string group. At this time, the temperature sensing unit 120 may be provided with only one sensor, which is commonly applied to a plurality of PV string groups.

The plurality of connection module modules 130_1 and 2 are connected to the outputs of the plurality of PV string groups to transmit monitoring information on the output of each PV string group to the monitoring server 20, . Here, the PV string group may include a plurality of predetermined PV strings.

One of the plurality of connection module modules 130 (130_1, 2) is a master connection module 130_1, and the rest except for one master connection module may be a slave connection module 131_2.

Here, the master connection half module 130_1 and the slave connection half module 130_2 can perform master and slave communication such as I2C and RS485, which are basically provided by the microprocessor. The master connection module 130_1 and the slave connection module 130_2 may be connected to each other via a connector and a bus bar 137.

1 and 2, a plurality of connection half modules 130 are configured as one master connection half module 130_1 and one slave connection half module 130_2. However, a plurality of connection half modules 130 may be composed of only one master connection half module 130_1 and the number of slave connection half modules 130_2 connected together with the master connection half module 130_1 may also be varied.

The master connection module 130_1 can inquire the module sear module 130_2 for the module deterioration degree of the PV string group at a predetermined period and at a point of time when the sensed irradiance exceeds the reference value. Subsequently, the master connection module 130_1 can also receive the module deterioration of the PV string group in response to each slave connection module 130_2 and transmit it to the monitoring server 20.

Hereinafter, the configuration of each connection module 130 will be described with reference to FIG.

Each connection module 130 includes a relay 131, a voltmeter 132, an ammeter 133, an ADC 134 and a microprocessor 135. In addition, each connection module 130 is connected between the output of each PV string group and the fuse 137 to provide a diode 136 to prevent reverse current, a fuse 137 to block the overcurrent, And a bus bar 137 connecting the outputs in parallel or in series. The master connection half module 130_1 and the slave connection half module 130_2 have substantially the same configuration but the master connection half module 130_1 is provided with a communication module 138 for communicating with the monitoring server 20, And a power supply unit 139 for supplying power to the slave connection module 130_2.

The relay 131 includes a first relay connected in series to one polarity of the output of each PV string group and a second relay connected in parallel with one resistor to one polarity and the other polarity of the output of each PV string group, 2 relays. The control of the relay 131 by the microprocessor 135 will be described with reference to Figs. 3A to 3C.

The voltmeter 132 is connected in parallel to the positive (+ and -) terminals of the output of the PV string group to which it is connected to measure the positive voltage of the PV string group.

The ammeter 133 is connected in series to the anode (usually positive) of the output of the PV string group to which it is connected to measure the output current of the PV string group.

The ADC 134 converts the measured voltage and current from the voltmeter 132 and the ammeter 133 into a digital value and transfers it to the microprocessor 135. When the ADC function is embedded in the microprocessor 135, the ADC 134 may be omitted.

The microprocessor 135 switches to the deterioration diagnosis mode if the preset period and the insolation amount meet a predetermined threshold value so as to control the relay 131 so that the PV string 132 and the ammeter 133, The current and open current of the group is measured and obtained.

Here, the preset period may be five days. The threshold value may be, for example, 500 (W / m < ² >) as an amount of solar radiation at which each solar cell module can produce electricity to some extent.

At this time, the microprocessor of the master connection module 130_1 may determine whether to switch to the deterioration diagnosis mode based on the solar radiation sensed for a predetermined period, and instruct the slave connection module 130_2 to switch to the deterioration diagnostic mode. However, the microprocessor of the slave connection module 130_2 may be switched to the degradation diagnostic mode according to an instruction (query) of the master connection module 130_1 without performing the determination for the mode change.

The microprocessor 135 compares the module open-circuit voltage Vocm and the module short-circuit current Iscm in the PV string group with the initial open-circuit voltage Voc of the module and the initial short-circuit current Ioc in consideration of environmental characteristics The module variances dV (i) and dI (i) can be calculated as shown in Equation (1).

Here, Vocm and Iscm are included in each PV string group in the open-circuit voltage and short-circuit current of each PV string group measured by the voltmeter and ammeter 133, as the present open-circuit voltage and the current short circuit current of the solar cell module in the PV string group The number of solar cell modules may be divided by the number of solar cell modules.

And Voc and Isc may be an initial open-circuit voltage (Voc) and an initial short-circuit current (Isc) of a module provided by a maker of a solar cell module (hereinafter referred to as a module maker).

Tref is the reference temperature (module temperature) provided by the module manufacturer, and may be the temperature at which the initial open-circuit voltage and the initial short-circuit current are measured. T is the currently measured module temperature, G is the reference solar irradiance, S is the module surface area provided by the module manufacturer, and N is the number of solar cells in the module. Also, a is a constant of the current temperature coefficient for applying the characteristic change of the short-circuit current according to the module temperature, and b is a constant of the voltage temperature coefficient for applying the characteristic change of the open- Where a, b may be constants derived from the temperature characteristic graph of the voltage / current provided by the module manufacturer.

The initial open-circuit voltage and the initial short-circuit current of the above-described module are measured for one module at a reference temperature (usually 25 degrees) and an irradiation dose of 1000 [W / m ² ], which is a standard test environment. 133 and the PV string group measured by the voltmeter 132 may be measured for different solar irradiance and for one or more modules at different module temperatures than the reference temperature. However, in the present invention, the module open-circuit voltage and the short-circuit current of each PV string group are adjusted (normalized) according to the standard test environment in consideration of the current module temperature, the irradiation amount, the module number and the surface area of each PV string group, It is possible to more accurately calculate the module variation of each PV string group which is a percentage of the calculated difference.

The microprocessor 135 calculates the module variation of the PV string group 10 times, and then calculates the standard deviation (sV, sI) of each module variation as shown in the following equation (2).

및

는 복수 회 산출된 각 PV 스트링 그룹의 모듈 변이도의 평균치일 수 있다.here,

And

May be an average value of module variances of each PV string group calculated a plurality of times.

,

)를 모니터링 서버(20)로 전송할 수 있다.If the standard deviation of the module variation is less than the preset reference value, the microprocessor 135 determines the module deterioration degree of each PV string group (

,

) To the monitoring server (20).

Here, when the microprocessor 135 of the master connection stage receives the module deterioration of each PV string group from the microprocessor 135 of each slave connection module 130_2, the module deterioration degree of each PV string group is integrated To the server (20). At this time, the microprocessor 135 of the master connection module can distinguish module deterioration for each PV string group, which is calculated by the slave connection module 130_2, (20).

This variation of the module has a feature that its deviation is not large. If the deviation (standard deviation) is large, there is a possibility of error or failure. However, according to the present invention, since only the module deterioration information in the case where no error occurs is transmitted to the monitoring server 20, it is possible to prevent the problem of receiving false deterioration information due to the temporary error.

Alternatively, the microprocessor 135 may notify the monitoring server 20 of an error occurrence or occurrence of an error when the standard deviation of the module variation exceeds a reference value a plurality of times.

On the other hand, the microprocessor 135 can notify the monitoring server 20 of the occurrence of an abnormality if the insolation amount does not exceed the threshold value from the current cycle to the next cycle. Accordingly, in the present invention, when the PV module does not operate normally due to external factors such as fallen leaves or dust, the monitoring server 20 can inform the monitoring server 20 of the cause and position of the PV module, .

On the other hand, the microprocessor 135 operates in a monitoring mode other than the predetermined period. In the monitoring mode, the output voltage and the current of each PV string group are monitored every second predetermined period (for example, one day) To the monitoring server (20).

In particular, in the monitoring mode, the microprocessor 135 determines whether the outputs of the respective PV string groups are connected in series or in parallel via the bus bar 137 to be transferred to an inverter (not shown) It is possible to keep the relay 131 so that power is transferred to the inverter (not shown) and monitor the output voltage and output current from each PV string group.

In addition, in the above-described embodiment, if there is a PV string group with excessive module deterioration among the PV string groups, that is, the operation efficiency of the PV string group is very poor, the power of the other PV string group In the case of obstructing the production, the relay 131 may be controlled to stop the power generation using the PV string group having the severe module deterioration. For example, the microprocessor 135 controls the relay 131 if there is a PV string group whose module variation is below a predetermined operating criterion among each PV string group - for example, the first and second relays are opened - to stop power generation by the corresponding PV string group.

In the case described above, the microprocessor 135 can inform the monitoring server 20 of the interruption of the corresponding PV string group, and stop the power generation according to the instruction from the monitoring server 20 or the master connection module 130_1 It is possible.

The master connection module 130_1 performs power supply to the slave connection module 130_2 and communication arbitration between the slave connection module 130_2 and the monitoring server 20, Even if the power generation is stopped by the PV string group, the functional blocks of the microprocessor, the communication module, etc. can continue to operate.

On the other hand, even if the operation of all the function blocks is stopped, the slave connection module 130_2 does not affect the operation of the other slave connection module 130_2 or the master connection module 130_1, The suspended slave connection module 130_2 may stop the operation of all the function blocks. This may be possible by turning off the power supplied to the slave connection module 130_2 by the master connection module 130_1 or by driving the microprocessor of the slave connection module 130_2 in the sleep mode.

On the other hand, in the above-described embodiment, a high-grade microprocessor having a high calculation accuracy can be applied to the master connection half module, and a low-grade microprocessor having a somewhat lower calculation accuracy can be applied to the slave connection half module.

As described above, according to the present invention, the deterioration degree of each PV string group is diagnosed and the diagnostic result is transmitted when the deterioration degree is high. Therefore, among the PV string groups provided in the photovoltaic power generation system, It is possible to predict the replacement timing of each PV string group and the like.

In addition, in the present invention, when each solar cell module operates properly, the deterioration degree of the solar cell module per PV string group can be diagnosed considering the environmental characteristics to which each PV string group is applied, Can be diagnosed.

Accordingly, the embodiment of the present invention can solve the problem of erroneous measurement of the module deterioration due to a direct solar radiation reduction factor caused by shadows, leaves, subsidiary materials, or the like and module temperature rise.

Hereinafter, relay control in the deterioration diagnosis mode and the monitoring mode according to the embodiment of the present invention will be described with reference to FIGS. 3A to 3C. FIG. 3A and 3B are diagrams showing relay control in a deterioration diagnosis mode according to an embodiment of the present invention, and FIG. 3C is a diagram illustrating relay control in a monitoring mode according to an embodiment of the present invention.

3A, ammeter 133 is connected in series to positive (+) poles of each PV string group to measure the output current of one end of each PV string group.

A voltmeter 132 is connected in series to the positive (+) and negative (-) poles of each PV string group to measure the output voltage of each PV string group.

The relay 131 includes first and second relays (Relay 1 and 2), and the first and second relays (Relay 1 and 2) can measure the open-circuit voltage, short-circuit current or output voltage of each PV string group Lt; RTI ID = 0.0 > 135 < / RTI >

The first relay (Relay1) is connected in series to the positive (+) pole of the output of each PV string group and the second relay (Relay2) is connected to the positive (+) and negative (Rsc).

In the deterioration diagnosis mode, the microprocessor 135 can open the first and second relays (Relay 1 and 2) and measure the open voltage of the PV string group as shown in FIG. 3A. In addition, the microprocessor 135 may measure the short-circuit current of the PV string group by opening the first relay Relay1 and shorting the second relay Relay2 as shown in FIG. 3b.

Thereafter, the microprocessor 135 calculates the module variation of the PV string group by the open-circuit voltage and the short-circuit current of the PV string group as described above, and transmits the module variation calculated by the monitoring server 20 at least at a predetermined moment can do.

3C, the microprocessor 135 may measure the output voltage and the output current of the PV string group by shorting the first relay (Relay1) and opening the second relay (Relay2) in the monitoring mode.

Thus, in the present invention, it is possible to diagnose and monitor the deterioration degree of each PV string group periodically by adding output voltage and output current as well as means capable of measuring the module deterioration degree to the output of each PV string group.

Hereinafter, a deterioration diagnosis method for a solar cell module according to an embodiment of the present invention will be described with reference to FIG. 4 is a flowchart illustrating a deterioration diagnosis method of a solar cell module according to an embodiment of the present invention.

Referring to FIG. 4, if the master connection half module has a predetermined period (YES in S410), it is checked whether the measured solar irradiation amount exceeds a preset threshold value (S420).

If the measured solar radiation exceeds the threshold, the slave connection module is queried for module deterioration of the PV string group connected thereto (S430).

The master connection half module and the slave connection half module measure the module average open-circuit voltage and the module average short-circuit current (open-circuit voltage and short-circuit current of the module in the PV string group) of the PV string group connected to them, The open-circuit voltage, the open-circuit voltage, and the initial short-circuit current) and the environment characteristics, the module variation being a percentage of the difference between the values of the module open-circuit voltage and the value obtained by normalizing the measured value of the short-circuit current, is calculated a plurality of times (S440-450).

At this time, each connection module can calculate the open-circuit voltage and the short-circuit current of the module a plurality of times when the radiation amount measured in the predetermined period exceeds the threshold value. Here, if there is no moment when the insolation amount exceeds the threshold value from the current cycle to the next cycle, each connection module can warn the monitoring server 20 of abnormality of the solar power generation system 10 or the radiation dose sensing unit.

The master connection half module and the slave connection half module calculate the standard deviation of the module variation calculated a plurality of times (S460).

The master connection half module and the slave connection half module check whether the standard deviation of module variation is less than a predetermined reference value (S470).

If the standard deviation of the module variation is less than the reference value, the master connection half module and the slave connection half module transmit the module deterioration degree which is the average module variation (S480). In particular, the slave connection module can transmit the module degradability to the master connection module in response to the module degradation query from the master connection module. The master connection module can collect the module deterioration measured by the module and the module deterioration degrees from all the slave connection module connected thereto and transmit the result to the monitoring server 20.

On the other hand, the master connection module operates in the monitoring mode except for the predetermined period, and can measure the output voltage of the PV string group connected thereto. The master connection module also queries the output voltage of the PV string group connected to the slave connection module, receives the output voltage of the PV string group in response to the output voltage of the PV string group, (S490).

In addition, if the standard deviation of the module variation is equal to or greater than a preset reference value in step S470, the master connection half module and the slave connection half module can ignore the measured plurality of module variations. Thereafter, the master connection half module and the slave connection half module can perform the process of measuring the module mutuality again.

When the standard deviation of the module variation is equal to or greater than the reference value, the master connection half module and the slave connection half module can notify the monitoring server 20 of the occurrence of the error. At this time, the master connection half module and the slave connection half module may notify the monitoring server 20 of an error occurrence after performing the process of measuring the module variation at least once.

While the present invention has been described in detail with reference to the accompanying drawings, it is to be understood that the invention is not limited to the above-described embodiments. Those skilled in the art will appreciate that various modifications, Of course, this is possible. Accordingly, the scope of protection of the present invention should not be limited to the above-described embodiments, but should be determined by the description of the following claims.

10: PV system 20: Monitoring server
110: radiation dose sensing unit 120: temperature sensing unit 130: connection module
131: Relay 132: Voltmeter 133: Voltmeter
134: ADC 135: Microprocessor 136: Diode and fuse
137: Bus Bar 138: Communication module 139: Power source

Claims (4)

A solar radiation detector for measuring solar radiation in an installation environment of the solar cell system; And
A plurality of connection submodules coupled to each PV string group of one solar cell array of the solar cell system and each comprising a processor, a measurement means and a relay,
Each of the processors switches to the deterioration diagnosis mode at a point of time when the insolation exceeds a predetermined threshold value every predetermined period and controls the relays so that the output of each PV string group is opened or short- The present open-circuit voltage and current short-circuit current of each PV module included in each PV string group are measured,
Each PV string group comprising a plurality of PV modules,
Voc is the current open-circuit voltage of the solar cell module in the PV string group, Iscm is the current short circuit current, Voc is the initial open-circuit voltage of the connection module, Isc is the initial short circuit current of the connection module, S is the surface area of the connection half module, N is the number of the solar cell in the connection half module, a is the connection half module temperature, and T is the current measured connection half module temperature, G is the reference irradiation dose, And b is a voltage temperature coefficient for applying the characteristic change of the open-circuit voltage according to the connection module temperature,
Each processor calculates module variances dV (i), dI (i)

(1)
, ≪ / RTI >

And

Is the module deterioration degree which is an average value of module mutations of each PV string group calculated ten times,
Each processor calculates the module variability of the PV string group by 10 times, and then calculates the standard deviation sV, sI of each module variation,

(2)
, ≪ / RTI >
The number of solar cells in each PV module, the surface area of each PV module, the voltage temperature coefficient of each PV module, and the current temperature coefficient of each PV module are determined by the manufacturer of each PV module included in each PV string group Wherein the reference temperature and the reference solar radiation amount are a temperature and an irradiation dose of a standard test environment,
If the standard deviation of the module variation is equal to or less than a predetermined reference value, each processor determines module deterioration degree

And

And transmits an error occurrence message to the monitoring server when the standard deviation of the module variation exceeds a predetermined reference value, and transmits an error occurrence message to the monitoring server. . The method of claim 1,
Each relay includes a first relay connected in series to one polarity of the output of each PV string group and a second relay connected in parallel to a dual polar of the output of each PV string group ,
Wherein each of the measurement means includes a voltmeter and an ammeter for measuring current and voltage at the output of each PV string group,
Wherein each of the processors measures an open-circuit voltage of each PV string group by the voltmeter in a state in which the first and second relays are opened, and when the first relay is opened and the second relay is short- , Measuring the short circuit current of each PV string group by the ammeter, dividing the number of the plurality of PV modules included in each PV string group by the open-circuit voltage and the short-circuit current of each PV string group, And the current short circuit current is calculated. The method of claim 1,
Wherein each of the plurality of connection module modules further includes a temperature sensor for sensing a current temperature of each PV module included in each PV string group. 2. The system of claim 1,
And notifies the occurrence of an abnormality when the radiation dose does not exceed the threshold from the current cycle to the next cycle.

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