KR20180121754A - The diagnosis system with multi-channel pv dc arrays - Google Patents

Abstract

The present invention relates to a multi-channel solar DC array failure diagnosis apparatus. The failure diagnosis apparatus according to the present invention includes an I-V measurement unit for each channel for measuring a power measurement value, a voltage measurement value, and a current measurement value of a solar string; and a determination unit for determining whether there is a failure by comparing the measurement values obtained from the I-V measurement unit with a power reference value, a voltage reference value, and a current reference value. Also, the failure diagnosis apparatus according to the present invention includes an output unit for outputting a determination result of the determination unit with an I-V curve, and a control unit for controlling data transmission to the determination unit and measurement for each channel of the I-V measurement unit. The I-V measurement unit includes a MOSFET as a switching element and a capacitor as a load for measuring a voltage. According to the present invention, a failure diagnosis for the multi-channel solar DC array can be simply performed while performing a diagnosis for each solar string.

Description

[0001] The present invention relates to a multi-channel photovoltaic DC array fault diagnosis apparatus,

The present invention relates to a multichannel photovoltaic DC array fault diagnosis apparatus, and more particularly, to a diagnosis apparatus capable of diagnosing a multichannel photovoltaic DC array with ease while diagnosing solar photonic strings.

Conventional fossil fuels such as coal and oil have economic problems due to depletion of resources, and serious environmental problems such as air pollution and global warming. Therefore, the need for alternative energy sources such as solar energy, wind energy, hydro energy, or fuel cells is increasing. Among them, solar energy is permanent, and because there is no environmental pollution problem, it is expected as renewable energy.

Solar power generation and photovoltaic generation are examples of ways to use solar energy. Solar power generation is a way to reflect solar heat to a mirror and concentrate it in one place to get the electricity by operating the steam turbine with the heat energy obtained at a very high density. Photovoltaic power generation is a method of converting light into electricity using a solar cell using a photovoltaic effect of a semiconductor material.

Solar power generation has attracted interest from early on because it can be installed in a small space because it does not need a steam turbine, and it has a low maintenance factor and a low maintenance cost. However, the efficiency of the solar cell is low, and the manufacturing cost is so high that it can not be widely used. Recently, high-efficiency solar cells have been developed, solar panel cost has been lowered, and the price and installation cost of other equipment such as DC-AC inverter has been decreasing.

One of the disadvantages of photovoltaic power generation is that it can only be performed during the day, because it depends on the solar power, and it is affected by the weather and the season. That is, the performance of the solar power generation apparatus changes depending on environmental factors such as the sunlight intensity, the temperature, and the wind speed.

Since it is technically difficult to manufacture solar cells uniformly in large size, generally, small-sized solar cell cells are connected in series or in parallel, and solar cell modules (panels) Is sold. In large-scale solar power generation, these solar cell modules are connected in series and parallel to obtain sufficient voltage and current. The series connection of solar cell modules is called a solar cell string, and the connection of such solar cell strings in parallel is called a solar cell array.

The power generated by the solar cell is DC power and must be converted to AC for transmission. In a large photovoltaic power generation complex, a plurality of DC solar cell arrays are connected in parallel to each other to generate DC power. And connected to a solar power inverter to convert it to AC power. At this time, if the voltages of the plurality of DC arrays are different, a mismatch loss may occur in the inverter.

Thus, if some modules are contaminated or degraded in performance, the output power of the entire solar array as well as the solar string is degraded, so it is necessary to repair or replace the degraded module. Therefore, it is important to monitor the status of solar modules, strings, and arrays from time to time. However, it is impossible to monitor numerous solar modules from time to time in large PV plants. Therefore, a monitoring apparatus or method for a solar string or an entire array is being studied.

The existing array tester is a device that can measure the I-V curve by measuring the amount of solar radiation and the voltage and current of the array. However, multichannel measuring instruments capable of measuring I-V curves at the same time are not widely spread due to problems such as size and cost.

Korean Patent Registration No. 10-1669340 Korean Patent Registration No. 10-0944793

Accordingly, it is an object of the present invention to provide an apparatus capable of diagnosing a solar light string and facilitating diagnosis of a failure in a multi-channel photovoltaic DC array.

The present invention also provides a multi-channel solar photovoltaic array fault diagnosis system capable of converting into standard test conditions (STC) (typically 25 ° C, 1000 W / m 2, AM: 1.5) It is another object to provide a device.

Another object of the present invention is to provide a multi-channel photovoltaic DC array fault diagnosis apparatus capable of anticipating reduction in efficiency due to mismatch in an inverter when converted to AC.

In addition, the present invention provides a multi-channel optical module capable of more precisely diagnosing a sunlight string or an array in consideration of a sunlight intensity at the time of measurement, a surface temperature of the solar cell module, and deterioration due to aging of the solar cell module. It is another object to provide a photovoltaic DC array fault diagnosis apparatus.

It is another object of the present invention to provide a multi-channel photovoltaic array fault diagnosis apparatus capable of specifically determining whether or not an abnormality of a photovoltaic power generation string is caused by reduction in efficiency due to deterioration of modules, module breakage, For other purposes.

In the present invention, the multi-channel solar DC array fault diagnosis apparatus for achieving the above object, a power measurement of the photovoltaic strings (P _{max, meas),} the voltage measurement value (V _{max, meas),} the current measurement value (I and _{max, meas)} of the measurement channel by IV measurement unit, the measurement values obtained from the IV measurement section and a power reference value (P _{max, ref),} the voltage reference value (V _{max, ref),} a current reference value (I _{max, ref)} And an output unit for outputting a result of the determination by the determination unit along with an IV curve and a control unit for controlling data transmission to the channel measurement and determination unit of the IV measurement unit, The IV measuring section is provided with a MOSFET as a switching element and has a capacitor as a load for voltage measurement.

Preferably, the MOSFET uses one that does not incorporate a freewheeling diode.

Preferably, the apparatus further includes a sunlight intensity measuring unit for measuring the slope sunshine intensity (Ir _meas ).

Preferably, the reference values are obtained by using the following formula using Ir surface temperature (Ir _meas ) and surface temperature (Tm _esti ) of the solar cell module.

Preferably, the determination unit adds I-V measurement data for each channel to form I-V curve data of the entire solar DC array, and predicts the inverter efficiency of the entire solar DC array.

The present invention also provides a fault diagnosis method for a multichannel photovoltaic DC array, comprising the steps of: measuring a PV power value ( _{Pmax, meas} ), a voltage measurement value (Vmax _{, meas} ) I _{max, meas} ); a data transfer step of transferring data obtained in the IV measurement step to the determination unit in the control unit; and a data transfer step of transferring the data measured in the data transfer step and the power reference value P _{max, ref),} the voltage reference value (V _{max, ref),} a current reference value (I _{max, ref)} of the determination result obtained in the state determining step wherein the failure in the failure state determining step and an output unit for determining a failure if IV compares And an IV curve output step of outputting a curve together with a curve. The IV measuring unit has a MOSFET as a switching element and a capacitor as a load for voltage measurement.

Preferably, the method further includes a step of measuring the intensity of sunshine (Ir _meas ) in the sunshine intensity measuring part.

Preferably, the reference values are obtained by using the following formula using Ir surface temperature (Ir _meas ) and surface temperature (Tm _esti ) of the solar cell module.

 Preferably, the determination unit further includes an inverter mismatch prediction step of summing I-V measurement data for each channel to form I-V curve data of the entire solar DC array and predicting inverter efficiency of the entire solar DC array.

According to the present invention as described above, it is possible to easily diagnose a failure of a multichannel photovoltaic DC array while diagnosing solar light strings.

In addition, the measurement time can be shortened by using the capacitor and the MOSFET, and consequently, the fluctuation of the irradiation dose during the measurement is small, and conversion to the standard test condition is possible.

In addition, according to the present invention, it is possible to predict the efficiency reduction due to mismatch in the inverter when converting to AC through an I-V curve obtained by adding the respective channel data.

Further, according to the multichannel photovoltaic array fault diagnosis method of the present invention, in consideration of not only various parameters such as the sunlight intensity at the time of measurement, the surface temperature of the solar cell module, and deterioration due to aging of the solar cell module, The fault diagnosis for the solar string or array can be made more accurately.

Further, according to the present invention, it is possible to specifically determine whether or not an abnormality of the solar power generating string is caused by reduction in efficiency due to deterioration of the module, module breakage, disconnection or the like.

1 is a configuration diagram of an IV measuring apparatus using an electronic load of the prior art.
FIG. 2 is a configuration diagram illustrating a multi-channel connection method of a multi-channel IV measurement apparatus in a multi-channel solar photovoltaic array fault diagnosis apparatus according to an exemplary embodiment of the present invention.
3 is a block diagram showing the configuration of an IV measurement unit for each channel in a multi-channel solar photovoltaic array fault diagnosis apparatus according to an embodiment of the present invention.
4 is a flowchart illustrating a multi-channel IV measurement procedure of the multi-channel photovoltaic DC array failure diagnosis apparatus according to an embodiment of the present invention.
FIG. 5 is a block diagram illustrating a configuration of components of a multi-channel solar photovoltaic array fault diagnosis apparatus according to an embodiment of the present invention. Referring to FIG.
6 is a diagram showing a composite IV curve of an entire DC array according to the series-parallel coupling of measured solar modules in a multi-channel solar photovoltaic array fault diagnosis apparatus according to an embodiment of the present invention.
FIG. 7 is a flowchart illustrating a procedure of fault diagnosis in the IV measurement result of the multi-channel photovoltaic DC array fault diagnosis apparatus according to an embodiment of the present invention.

The above and other objects, features and advantages of the present invention will become more apparent from the following description taken in conjunction with the accompanying drawings, in which: . In the following description, well-known functions or constructions are not described in detail since they would obscure the invention in unnecessary detail.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a configuration diagram of an I-V measuring apparatus using a conventional electronic load.

The characteristics of the solar cell module used in the photovoltaic power generation can be obtained mainly by using the circuit shown in Fig. 1 (a). Referring to FIG. 1, solar cell modules 102 are assembled to constitute a solar cell module 104. The electronic load 106 is attached to measure the characteristics of the solar cell module 104 to measure current and voltage.

The measurement result of the solar cell module can be represented by the IV curve in Fig. 1 (b). When the resistance of the electronic load is increased, the voltage across the resistor becomes higher. In a typical Si solar cell, there is no significant change in the current flowing through the circuit up to a certain voltage. However, after a certain voltage, the current rapidly decreases, and the graph of FIG. 1 (b) is shown. The voltage and current at the point representing the maximum power (P _max ) are referred to as the maximum voltage (V _max ) and the maximum current (I _max ), respectively. The point that meets the current axis is the short circuit current (Isc), and the point where it meets the full compression is the open voltage (Voc).

FIG. 2 is a diagram illustrating a multi-channel connection method of a multi-channel IV measurement apparatus in a multi-channel solar photovoltaic array fault diagnosis apparatus according to an exemplary embodiment of the present invention. FIG. Channel photovoltaic array array fault diagnosis apparatus according to an embodiment of the present invention; FIG.

In general, a plurality of connection modules are connected and operated in a solar power generation capacity (100 kW or more), and a DC connection module 204 is provided with a number of products having a configuration in which a DC array of a maximum of 22 channels can be connected. Therefore, it takes many devices or time to diagnose each photovoltaic module. Therefore, a multi-channel device 206 capable of diagnosing each solar string 202a, 202b, 202c, and 202d while measuring the voltage and current of the entire solar array 202 is needed. However, there is a problem that the size increases and the cost increases when a multi-channel equipment is implemented.

The electronic load shown in Fig. 1 (a) is applied to the array tester machine which is mostly used. The advantage of using an electronic load is that it can control the measurement time, but it has a disadvantage that the size of the device is increased when it is measured using a multi-channel electronic load.

In addition, when I-V measurement is performed on the site of the solar power generation, the solar radiation and the temperature of the solar module largely affect the I-V measurement, thereby causing a measurement error.

In particular, since the load device uses electronic load to measure the voltage and current, the measurement time of a typical product takes a few seconds (commercial product: 10 sec). In the case of the solar photodetector, the measurement time may be several seconds or more, and if the amount of solar radiation varies during the measurement period, the measurement error may increase. Also, there is a disadvantage that it can not be converted into STC because of this disadvantage.

When a capacitor is used, it is possible to control the time like an electronic load when the capacitance is large, but it is difficult to commercialize the capacitor because of its large size. However, I-V curve measurement is possible when measuring the instantaneous charging voltage and current by reducing the capacitance of the capacitor.

According to one embodiment of the present invention, a capacitor 306 and a MOSFET 304 are used as a switching element instead of an electronic load as shown in Fig. The capacity of the capacitor 306 can be set to a small capacity, the measurement time can be shortened to about 0.02 second, and thus the variation in the amount of solar radiation is small.

As a switch that instantaneously connects the solar cell module 302 or array to the capacitor circuit in the field, a voltage-type MOSFET 304 is used among various power switching semiconductor devices. A typical FET device includes a freewheeling diode that is a parasitic diode, but in the present invention, it is preferable to use a MOSFET without a freewheeling diode for smooth switching operation.

In FIG. 3, it is possible to measure the input of the crystalline solar cell with the voltage between the + and - terminals of the solar cell array 302 input for each channel within 1000 V, and the open voltage and current within 15 A. In the I-V measuring device 300, the voltage is obtained at the voltage across the capacitor 306, and the current is obtained from the current 308 flowing when the MOSFET 304 is connected. The voltage and current are transmitted to the measuring device 310 and measured.

4 is a flowchart illustrating a multi-channel I-V measurement procedure of the multi-channel photovoltaic DC array failure diagnosis apparatus according to an embodiment of the present invention.

First, data is measured for each channel (S402). Next, an I-V graph is drawn using data for each channel (S404). The portion indicated by the instantaneous current characteristic of the capacitor in the data is converted through the I-V smoothing process for each channel for obtaining the interval average for each voltage 0.01 (S406). The short circuit current Isc at the saturation position of the I-V curve and the open-circuit voltage Voc at the change position are obtained (S408). Finally, the I-V curve for each array may be summed to obtain a comprehensive I-V curve of the solar array DC array (S410). The measuring apparatus displays the obtained I-V curve by a monitor or the like.

The measured I-V curve can convert the performance of the DC array group connected in parallel to the STC state by simultaneously measuring solar radiation, module surface temperature, and ambient temperature.

FIG. 5 is a block diagram illustrating a configuration of components of a multi-channel solar photovoltaic array fault diagnosis apparatus according to an embodiment of the present invention. Referring to FIG. The multichannel photovoltaic DC array fault diagnosis apparatus 500 includes a channel-specific IV measuring unit 502 for measuring the power measurement value, the voltage measurement value, and the current measurement value of the solar light string, the measurement values obtained from the IV measurement unit, A determination unit 504 for comparing the power reference value, the voltage reference value, and the current reference value to determine whether the failure has occurred, and an output unit 506 for outputting the determination result of the determination unit together with the IV curve. The control unit 508 controls the data transmission to the channel-by-channel measurement and determination unit of the I-V measurement unit, and is also involved in other measurement and output.

Although not shown in Fig. 5, the control unit can also control the brightness intensity measurement unit for measuring the brightness intensity when necessary.

FIG. 6 is a view showing a composite I-V curve of the entire DC array according to the serial-parallel combination of the photovoltaic modules measured in the multi-channel solar photovoltaic array fault diagnosis apparatus according to an embodiment of the present invention.

Connecting solar modules in series increases the voltage, so the entire compression section of the measurement result curve in the I-V graph becomes larger. Connecting PV modules in parallel increases the current, so the current-axis intercept of the measurement result curve becomes larger on the I-V graph.

Since I-V curves for each channel can be obtained, the characteristics of the solar strings connected to each channel can be obtained. And if each channel is connected to AC inverter, it can grasp the degree of mismatch.

On the other hand, since the I-V curve obtained by adding the respective channel data can be obtained, the characteristics (efficiency) of the entire solar array can be easily obtained and it is also possible to determine whether there is a problem in the serial or in the parallel in the entire graph. In addition, since the maximum power value of the entire array can be known, the efficiency reduction due to mismatch can be predicted when the entire DC power is converted into AC by the inverter.

In order to determine whether the solar array is in a normal state, the multi-channel solar photovoltaic array fault diagnosis apparatus uses the reference value data that is modeled based on the output value of the solar cell module at the initial installation. In other words, by comparing the IV value and the measured value IV, which reflects the system modeling data such as the environmental (solar, air temperature, wind speed) sensors, the current pollution degree of the module, and the installation year . Basically, if there are many differences between the measurement results and the simulation results, the system is judged as a failure.

7 is a flowchart illustrating a procedure for performing a fault diagnosis in the I-V measurement result of the multi-channel solar photovoltaic array fault diagnosis apparatus according to an embodiment of the present invention. Referring to FIG. 7, a method of diagnosing a solar DC string or array will be described in detail.

Various parameters must be considered for accurate diagnosis of PV strings or arrays. In other words, determining whether a malfunction is caused by only the voltage, current, and power measured in a photovoltaic power string or array may result in inaccurate results. For more accurate diagnosis, deterioration due to aging of the solar cell module should be considered in addition to various parameters such as the sunlight intensity at the measurement and the surface temperature of the solar cell module.

It is difficult to make an accurate diagnosis in the morning, evening, or day when the sun is low due to cloudy weather. For accurate diagnosis, the slopes sunshine intensity measured by adding (Ir _meas) performs the diagnosis when the slope sunshine intensity 250 W / m ² or more.

7, the values of the voltage (Vmax _{, meas} ) (V), current ( _{Imax, meas} ) A and power _{Pmax, meas} kW of the photovoltaic string _{, meas} (W / m ² ) (S 702, S 706) to diagnose whether or not the solar power generation string is faulty. The diagnosis of the failure is made by comparing the measured value of the PV string with the reference value. In the process of obtaining the reference value (S708), the surface temperature (Tm _esti ) of the PV module and the aging factor (D _aging ) (S704) to enable more accurate diagnosis.

Solar cells used in solar power generation use semiconductors with energy band gap. As the surface temperature increases, this energy band gap decreases and the output voltage decreases, resulting in a decrease in output power. Therefore, the surface temperature (Tm _esti ) of the photovoltaic module must be considered in the fault diagnosis of the PV string or array.

However, it is not easy to measure the surface temperature of the solar cell every solar module. Therefore, it is necessary to calculate the surface temperature (Tm _esti ) of the photovoltaic power generation module based on the measurement value (Ir _meas ) of the inclined plane sunshine intensity.

In one embodiment of the present invention, the surface temperature (Tm _esti ) (占 폚) of the solar cell module can be obtained by the following equation (1).

Here, Ir _meas is inclined sunshine intensity measured values ^{(W / m 2), Ta} aver the daily average outside temperature (℃), Vw _ref is a reference velocity (m / s), Vw _aver the daily average wind speed (m / s ), a _m and b _m denote the inclination angle of the sunshine strength temperature correction coefficient, and k _v denotes the solar module correction factor.

Reference wind speed Vw _ref = 1 m / s and the outside air temperature _Taaver and the wind speed Vw _aver can be obtained using the real time data of the weather station. Therefore, even if only the Ir _{meas of the} slope is measured, the surface temperature Tm _esti ) can be obtained by using Equation (1). By doing so, there is an advantageous effect that the cost of the measuring apparatus can be reduced and the measuring time is also reduced.

(Vmax _{, ref} ) (V) and the maximum current reference value ( _{Imax, ref} ) (A) are calculated from the surface temperature ( _Tmesti ) of the solar cell module and the _tilting intensity ( _Irmeas ) ) And the maximum power reference value (P _{max, ref} ) (kW) can be obtained by the following equation (2).

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In Equation 2, Ir _corr is inclined sunshine intensity correction value ^{(W / m 2), D} incident is an incident angle dependence coefficient, D _soil is PV string contamination coefficient, D _aging the PV module aging factor, D _aging0 is Driving year 0 year PV module aging factor, D _agingN is driving year number N year PV module aging factor. In addition, a _v and b _v are voltage correction coefficients, α _t is the PV module temperature coefficient, N _series is the number of PV modules in series, a _i and b _i are the current correction factors, and N _parallel is the PV module parallel And R _l represents the resistance of the solar module.

(Ir _meas ), solar _incident angle (D _incident ), degree of contamination of the solar power generation string (D _soil ), photovoltaic power generation The aging of the module (D _aging ) and the surface temperature (Tm _esti ) of the solar module can be reflected (S704), enabling more accurate diagnosis.

The diagnosis of the failure of the PV string or array is made by comparing the solar PV string output power residual (P _{max, resi} ), output current residual (I _{max, resi} ) and output (Vmax _{, resi} ) (S710, S712). At this time, the photovoltaic generation string output power residuals (P _{max, resi} ), output current residuals (I _{max, resi} ), and output voltage residuals (V _{max, resi} )

In Equation 3 P _{max, meas} is PV string output power measured values _(kW), I _{max, meas} is PV string output current measured value _(A), V _{max, meas} is PV string output voltage is measured value _(V), P _{max, ref} is a photovoltaic string output power reference value _(kW), I _{max, ref} is a photovoltaic string output current reference value _(A), V _{max, ref} is a photovoltaic string output voltage reference value ( V).

(PV _{max, resi} ), output current residual (I _{max, resi} ), and output voltage residual (V _{max, resi} ) obtained by the formula (3) Respectively. In particular, data were gathered so that the efficiency of the PV string could be specifically determined by the efficiency reduction, module breakage, and disconnection due to deterioration of the module. As a result, the fault diagnosis result information of Table 1 and Table 2 was obtained.

P _{, max, resi} V _{, max, resi} I _{max, resi} Failure mode 0 to -0.1 -0.1 to 0.1 -0.1 to 0.1 0 Less than -0.1 0 or more -0.2 or higher One Less than -0.1 0 or more Less than -0.2 2 Less than -0.1 Less than -0.1 -0.05 ~ 0.05 3 Less than -0.1 Less than -0.2 -0.05 ~ 0.05 4 Less than -0.1 Less than 0 Less than -0.1 5 Less than -0.1 -1 or less -1 or less 6

Failure mode  Information on fault diagnosis result 0 Solar power string normal One More than solar power string
(Efficiency reduction, deterioration, cell crack, ribbon failure) 2 More than solar power string
(Three or more modules with reduced efficiency, deterioration, cell crack, ribbon failure) 3 PV string defects
(Damage of module 1-2, ribbon disconnection, cell breakage) 4 PV string defects
(Three or more modules damaged, deteriorated, cell cracks, bad ribbons) 5 PV Strings Abnormal & Defective
(One module reduced efficiency, some cell breakdown diode some operation) 6 Solar power string stop
(Lead wire break, module breakage, diode all burned out)

In Table 1 _{, Pmax and resi} are checked (S710), and when it is -0.1 or more, a normal result is output (S718). If P _{max, resi} is checked (S 710), if V _{max, resi} and I _{max, resi} are checked (S 712). In this case, the corresponding failure mode is output from Table 1 (S714). Then, the failure diagnosis result information corresponding to the failure mode is output to the display unit in Table 2 (S716).

By using this diagnostic method, it is possible to detect the abnormalities of the photovoltaic power strings according to the photovoltaic string output power residuals ( _{Pmax, resi} ), output current residuals ( _{Imax, resi} ), and output voltage residuals (Vmax _{, resi} ) It is possible to concretely judge whether or not the module is broken down due to the deterioration of the module due to the deterioration of the module or the like as shown in Table 1 and Table 2,

Having described specific portions of the present invention in detail, those skilled in the art will appreciate that these specific embodiments are merely preferred embodiments and that the scope of the present invention is not limited thereby. something to do. It is therefore intended that the scope of the invention be defined by the claims appended hereto and their equivalents.

Claims (7)

An IV measurement unit for each channel for measuring a power measurement value, a voltage measurement value, and a current measurement value of the solar light string,
A determination unit for comparing the measurement values obtained from the IV measurement unit with a power reference value, a voltage reference value,
An output unit for outputting the determination result of the determination unit together with the IV curve,
And a controller for controlling data transmission from the IV measuring unit to the channel-by-channel measurement and judgment unit,
Wherein the IV measuring unit includes a MOSFET as a switching device and a capacitor as a load for voltage measurement.
The method according to claim 1,
Wherein the MOSFET is not provided with a freewheeling diode.
The method according to claim 1,
And a sunlight intensity measuring unit for measuring a sunlight intensity of the slope of the multi-channel photovoltaic DC array.
The method according to claim 1,
Wherein the determination unit forms the IV curve data of the entire photovoltaic DC array by summing the IV measurement data for each channel and predicts the inverter efficiency of the entire photovoltaic DC array.
An IV measurement step for measuring the power measurement value, the voltage measurement value, and the current measurement value of the solar light string in the IV measurement unit for each channel,
A data transfer step of transferring data obtained in the IV measurement step to a determination unit in a control unit,
A failure determination step of determining whether a failure has occurred by comparing the measured values transmitted in the data transfer step with a power reference value, a voltage reference value, and a current reference value,
And an IV curve output step of outputting the judgment result obtained in the failure judgment step in the output part together with the IV curve,
Wherein the IV measuring unit includes a MOSFET as a switching device and a capacitor as a load for voltage measurement.
6. The method of claim 5,
Further comprising a sunlight intensity measurement step of measuring a sunlight intensity (Ir _meas ) at the sunlight intensity measuring unit.
6. The method of claim 5,
Further comprising an inverter mismatch predicting step of forming IV curve data of the entire solar photovoltaic array by summing the channel-specific IV measurement data in the determination section and predicting the inverter efficiency of the entire solar photovoltaic array. Channel Photovoltaic DC Array Fault Diagnosis Method.

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