KR102159768B1 - Apparatus and method for diagnosing hot spot of photovoltaic array - Google Patents

Abstract

The present invention relates to an apparatus for diagnosing a hot spot of a photovoltaic array, comprising: a loss estimating unit that calculates an actual measured value of the mismatch loss of the photovoltaic array and calculates an estimated value of the mismatch loss of the photovoltaic array; And, from the actual measured value of the photovoltaic array mismatch loss calculated by the loss estimator and the estimated value of the photovoltaic array mismatch loss, the difference value of the photovoltaic array mismatch loss is calculated, and the calculated photovoltaic array mismatch loss difference And a hot spot generation determination unit that compares the value with a set reference value and determines that a hot spot has occurred in the photovoltaic array when the number of occurrences satisfying the reference value exceeds the set value. Therefore, it is possible to diagnose the hot spot of the photovoltaic power generation array without having to directly maintain the photovoltaic system by providing special equipment to diagnose the occurrence of the hot spot of the photovoltaic power generation array. There is an effect that can reduce cost and guarantee performance and quality.

Description

Photovoltaic array hot spot diagnosis device and method {APPARATUS AND METHOD FOR DIAGNOSING HOT SPOT OF PHOTOVOLTAIC ARRAY}

The present invention relates to an apparatus and method for diagnosing Hopt Spot of a photovoltaic array, and more particularly, output of a photovoltaic system from measurement data of a photovoltaic system acquired at a predetermined period from a database during operation of the photovoltaic system. The present invention relates to a hot spot diagnostic device for solar photovoltaic arrays that monitors the power drop and diagnoses that a hot spot has occurred in the photovoltaic array from this, and makes quick failure recovery and maintenance decisions for the photovoltaic array. .

The photovoltaic power generation system is composed of a photovoltaic power generation array that converts the input energy intensity of sunlight into DC power and outputs it, and a photovoltaic power generation inverter that outputs the DC power of the photovoltaic power generation array into AC power. The photovoltaic power generation module of such a photovoltaic power generation system is composed of parts sensitive to the influence of temperature, humidity, power loss, and the surrounding environment, so when a failure occurs, the photovoltaic power generation array may not produce the expected power generation performance.

Solar photovoltaic arrays are mainly installed outdoors, so shading occurs in the photovoltaic array, circuit defects occur in the wiring of the photovoltaic array, or short-circuit current is reduced due to variations in output power of the photovoltaic module. As a result, a hot spot, which is a local overheating phenomenon of the solar power array, occurs. In addition, when a hot spot occurs, the solar cell or glass is damaged, the output power of the photovoltaic array is lowered due to melting of the soldering area, and the photovoltaic module is deteriorated.

In addition, as the output power of the photovoltaic power generation array decreases due to the hot spot of the photovoltaic power generation module, the stability of the photovoltaic power generation array decreases and economic loss is caused.

However, it is difficult to determine whether a hot spot of a solar power module has occurred with the naked eye or remotely, and it is necessary to diagnose whether a hot spot has occurred using special equipment such as a thermal imaging camera at the site. There is a limitation in that time and economic costs are incurred in diagnosing the occurrence of occurrence.

Accordingly, by diagnosing the occurrence of hot spots of the photovoltaic array from the measurement data collected from the photovoltaic power generation system without any special equipment, rapid failure recovery of the photovoltaic power generation array operation and the maintenance of the photovoltaic power generation array are determined. There is a need to develop a technology that provides diagnostic information that can be used in the future.

Republic of Korea Patent Publication No. 10-1065862 (A method of estimating the maximum power of a solar power generation system according to the determination of partial shade of a solar cell array)

The technical problem to be achieved by the present invention is to diagnose that the output power of the photovoltaic power generation system is falling due to the hot spot of the photovoltaic power generation array from the information obtained from the database at a predetermined period, and this is used as the hot spot diagnosis information of the photovoltaic power generation array. By providing, it is to establish an efficient post-maintenance system for the solar power generation system and to guarantee and improve the performance and quality of the solar power system.

The hot spot diagnosis apparatus of a photovoltaic array according to an embodiment of the present invention includes solar equivalent operating time, equivalent operating time of a photovoltaic array, optimum equivalent operating time of a photovoltaic array, and temperature correction of a photovoltaic power generation array. Calculate the measured value of the mismatch loss of the photovoltaic power generation array from the equivalent operating time, estimate the DC voltage of the photovoltaic power generation array taking into account aging according to the operating years, the optimal equivalent operating time of the photovoltaic power generation array, and A loss estimating unit for calculating an estimated value of the mismatch loss of the photovoltaic array from the estimated value of the equivalent operating time after temperature correction and the estimated value of the equivalent operating time of the photovoltaic array; And, from the actual measured value of the mismatch loss of the photovoltaic array calculated by the loss estimating unit and the estimated value of the mismatch loss of the photovoltaic array, the difference value of the photovoltaic array mismatch loss is calculated, And a hot spot determination unit that compares the mismatch loss difference value with a set reference value, and determines that a hot spot has occurred in the photovoltaic array when the number of times that the reference value is satisfied exceeds the set value.

The solar equivalent operating time, the equivalent operating time of the photovoltaic power generation array, the optimum equivalent operating time of the photovoltaic power generation array, and the equivalent operating time after temperature correction of the photovoltaic power generation array are calculated and provided to the loss estimation unit. Operation time calculation unit; And, from the solar equivalent operating time and the surface temperature of the photovoltaic array, the DC voltage estimate value of the photovoltaic power generation array considering aging according to the operating years, the optimal equivalent operating time estimate value of the photovoltaic power generation array, and the photovoltaic power generation And an equivalent operating time estimation unit for calculating an equivalent operating time estimate value after temperature correction of the array and an equivalent operating time estimation value of the photovoltaic array and providing the loss estimation unit to the loss estimation unit.

The equivalent operation time calculation unit after correction of the solar equivalent operation time, the equivalent operation time of the photovoltaic array, the optimum equivalent operation time of the photovoltaic power generation array, and the temperature of the photovoltaic power generation array from Equations 1 and 2 below. It is characterized by calculating the equivalent operating time.

[Equation 1]

[Equation 2]

(At this time, Y _r,meas is the solar equivalent operating time, G _a,meas is the insolation intensity on the slope (W/m ² ), G _a,ref is the insolation intensity 1,000 (W/m ² ), and Y _a,meas is the solar power Actual measurement of power generation array equivalent operating time, P _a,meas is the solar photovoltaic array DC power (W), P _as is the solar photovoltaic array installation capacity (W) under standard test conditions (STC), and Y _ao,meas is solar Photovoltaic array optimal equivalent operating time measured value, Y _at,meas is the equivalent operating time measured value after photovoltaic array temperature correction, T _m,meas is the measured surface temperature of the photovoltaic array, and I _a,meas are solar photovoltaic power generation. Array DC current measured value, α _m is the solar photovoltaic array maximum performance factor, α _t is the photovoltaic array temperature correction factor, and R _a is the photovoltaic array DC line resistance.)

The equivalent operating time estimating unit is the DC voltage estimation value of the photovoltaic power generation array taking into account aging according to the operating years from Equation 3 below, the optimal equivalent operating time estimation value of the photovoltaic power generation array, and the equivalent after temperature correction of the photovoltaic power generation array It characterized in that it calculates the operating time estimate value and the equivalent operating time estimate value of the photovoltaic array.

[Equation 3]

(At this time, Y _ao,esti is the estimated value of the optimal operating time of the solar power array, Y _at,esti is the estimated value of the equivalent operating time after temperature correction of the photovoltaic array, Y _a,esti is the estimated value of the equivalent operating time of the solar power array, V _a,esti is the estimated value of the photovoltaic array DC voltage, D _v,aging is the photovoltaic array voltage aging factor, O _year is the number of operating years, I _a,meas is the actual measured value of the photovoltaic array DC current, and R _a is PV array DC line resistance, α _m is PV array maximum performance factor, α _t is PV array temperature correction factor, a _t , b _t is PV array temperature coefficient, a _v , b _v is solar Photovoltaic array voltage correction factor, N _series is the number of solar power modules in series, N _parallel is the number of solar power strings in parallel.)

The loss estimating unit is characterized in that it calculates the measured value of the mismatch loss of the photovoltaic array using Equation 4 below.

[Equation 4]

(At this time, Y _ao,meas are the measured value of the optimal equivalent operating time of the solar power array, Y _at,meas are the actual measured value of the equivalent operating time after temperature correction of the solar power array, and Y _lm,meas are the actual measured values of the solar power array mismatch loss. .)

The loss estimator is characterized in that it calculates an estimated value of the mismatch loss of the photovoltaic array using Equation 5 below.

[Equation 5]

(At this time, Y _ao,esti is an estimate of the optimal equivalent operating time of the solar power array, Y _at,esti is an estimate of the equivalent operating time after temperature correction of the solar power array, and Y _lm,esti is an estimate of the solar power array mismatch loss.)

The hot spot determination unit calculates a difference between the measured value of the mismatch loss of the photovoltaic array and the estimated value of the mismatch loss of the photovoltaic array from Equation 6 below as the difference value of the photovoltaic array mismatch loss, A difference between the measured value of the PV array direct current voltage and the estimated value of the direct current voltage of the photovoltaic array is calculated as the difference value of the direct current voltage of the photovoltaic array.

[Equation 6]

(At this time, Y _lm,resi is the solar photovoltaic array mismatch loss difference value, Y _lm,meas is the measured photovoltaic array mismatch loss, Y _lm,esti is the solar photovoltaic array mismatch loss estimate, and V _a,resi is solar Photovoltaic array DC voltage difference value, V _a,meas are PV array DC voltage measured values, V _a,esti are PV array DC voltage estimates)

The hot spot determination unit compares the solar equivalent operating time with a reference value of 0.2, compares the difference value of the photovoltaic array mismatch loss with the reference value A, compares the difference value of the photovoltaic array DC voltage with the reference value B, and The number of occurrences (Freq.) in which the comparison result of the equivalent operating time and difference values are all satisfied at the same time is judged whether or not a hot spot occurs from the result of the final comparison with the reference value C, and according to Equation 7 below, It is characterized in that it judges whether or not it occurs.

[Equation 7]

If (Y _{r, meas} <0.2);

Else if (Y _r,meas >= 0.2 and Y _lm,resi <A and V _a,resi> B and Freq. >C)

Hot spot occurrence;

Else

No hot spot;

End

(At this time, Y _r,meas are solar equivalent operating time, Y _lm,resi are solar photovoltaic array mismatch loss difference value, and V _a,resi are photovoltaic array DC voltage difference value.)

The reference value A is -0.06, and the reference value B is -0.1, and the reference value C is 8.

A method for diagnosing a hot spot of a photovoltaic array according to an embodiment of the present invention includes: calculating an equivalent operating time of the photovoltaic array; Calculating an optimal equivalent operating time of the photovoltaic array and the equivalent operating time after temperature correction of the photovoltaic array; Calculating a DC voltage of the photovoltaic power generation array in consideration of aging according to the number of operating years, an optimal equivalent operating time estimate value of the photovoltaic power generation array, and an equivalent operating time estimate value after temperature correction of the photovoltaic power generation array; Calculating an actual measurement value of the photovoltaic array mismatch loss and an estimated value of the photovoltaic array mismatch loss; Calculating a photovoltaic array mismatch loss difference value and a photovoltaic array direct current voltage difference value; Determining whether solar equivalent operating time and the difference values satisfy a set criterion; In addition, when the solar equivalent operating time and the difference values satisfy a set criterion, determining that a hot spot occurs, or when the solar equivalent operating time and the difference values do not satisfy a set criterion, determining that a hot spot does not occur; It characterized in that it comprises.

According to this feature, the hot spot diagnosis apparatus and method of a solar photovoltaic array according to an embodiment of the present invention can diagnose the hot spot occurrence of a photovoltaic power generation system from a remote location without additional equipment. There is an effect of reducing the cost required for fault diagnosis and guaranteeing the performance and quality of the solar power generation system.

1 is a block diagram schematically showing the overall structure of a photovoltaic power generation system to which an apparatus and method for diagnosing a hot spot of a photovoltaic array according to an embodiment of the present invention are applied.
2 is a block diagram schematically showing a hot spot diagnosis unit of a hot spot diagnosis apparatus of a photovoltaic array according to an embodiment of the present invention.
3 is a flow chart showing the flow of a method for diagnosing a hot spot of a photovoltaic array according to an embodiment of the present invention.
4 is a graph showing actual measurement values of the mismatch loss of the photovoltaic array and the equivalent operating time of the photovoltaic array calculated by the hot spot diagnosis apparatus and method of the photovoltaic array according to an embodiment of the present invention. .
5 is a graph showing an estimated value of the mismatch loss of the photovoltaic array and the equivalent operating time of the photovoltaic array calculated by the hot spot diagnosis apparatus and method of the photovoltaic array according to an embodiment of the present invention.
6 is a graph showing actual measured values and estimated values of the DC voltage of the photovoltaic array calculated by the apparatus and method for diagnosing hot spots of the photovoltaic array according to an embodiment of the present invention.
7 is a difference value of the mismatch loss of the photovoltaic array calculated by the hot spot diagnosis apparatus and method of the photovoltaic array according to an embodiment of the present invention, and the measured value and the estimated value of the direct current voltage of the photovoltaic array. It is a graph showing the difference value.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those of ordinary skill in the art can easily implement the embodiments of the present invention. However, the present invention may be implemented in various different forms, and is not limited to the embodiments described herein. In the drawings, parts irrelevant to the description are omitted in order to clearly describe the present invention, and similar reference numerals are assigned to similar parts throughout the specification.

1 is a block diagram schematically showing the overall structure of a photovoltaic power generation system to which an apparatus and method for diagnosing a hot spot of a photovoltaic array according to an embodiment of the present invention are applied, and FIG. It is a block diagram schematically showing the hot spot diagnosis unit of the hot spot diagnosis apparatus of the solar photovoltaic array according to the present invention, and FIG. 3 is a flow chart showing the flow of the hot spot diagnosis method of the solar photovoltaic array according to an embodiment of the present invention. 4 is a graph showing the actual measurement values of the mismatch loss of the photovoltaic array and the equivalent operating time of the photovoltaic array calculated by the hot spot diagnosis apparatus and method of the photovoltaic array according to an embodiment of the present invention, 5 is a graph showing an estimated value of the mismatch loss of the photovoltaic array and the equivalent operating time of the photovoltaic array calculated by the hot spot diagnosis apparatus and method of the photovoltaic array according to an embodiment of the present invention. 6 is a graph showing the actual measured value and the estimated value of the DC voltage of the photovoltaic array calculated by the hot spot diagnosis apparatus and method of the photovoltaic array according to an embodiment of the present invention. A graph showing the difference value of the mismatch loss of the photovoltaic array calculated by the hot spot diagnosis apparatus and method of the photovoltaic array according to an embodiment, and the difference between the measured value and the estimated value of the direct current voltage of the photovoltaic array to be.

Referring to FIGS. 1 to 2 and 4 to 7, a hot spot diagnosis apparatus of a photovoltaic array according to an embodiment of the present invention will be described. First, a hot spot diagnosis apparatus 200 of a photovoltaic array. (In this specification, a'Hot Spot diagnostic device' is mixed and described) is connected to the photovoltaic system 100, a database 210, a hot spot diagnostic unit 220, a diagnostic result display unit 230 and a memory ( 240).

The database 210 receives the solar intensity and surface temperature of the slope of the sun 10 and the DC voltage, DC current, and DC power values of the photovoltaic array 20 from the photovoltaic inverter 30 and stores them as measurement data. And solar equivalent operating time (Y _r,meas ) of the photovoltaic power generation system 100, the difference value of the photovoltaic array mismatch loss (Y _lm,resi ), and the difference value of the photovoltaic array DC voltage (V _a,resi) ), and the number of occurrences (Freq.) are stored respectively.

At this time, the photovoltaic power generation system 100 is a photovoltaic power generation array 20, a photovoltaic power generation inverter 30 connected to the photovoltaic power generation array 20, and a photovoltaic power generation inverter 30 that is irradiated with the intensity of sunlight. It includes a connected power system 40 and a load 50.

The structure of the photovoltaic power generation system 100 consisting of the photovoltaic power generation array 20, the photovoltaic power generation inverter 30, the power system 40 and the load 50 is well known, and thus, it is not described in detail in this specification. If not, it should be understood clearly.

The database 210 is connected to the memory 240, receives measurement data, measured values, estimated values, and data of the difference values from the photovoltaic system 100, transfers them to the memory 240 and stores them, and the memory 240 The reference value, etc. stored in may be transmitted to the hot spot diagnosis unit 220.

The database 210 measures measurement data at a sampling period of 2 seconds, and stores the measurement data measured by 10 to 15 minutes in the memory 240.

In the memory 240, the diagnosis result display unit 230 may receive and store diagnosis result data from the hot spot diagnosis unit 220.

The hot spot diagnosis unit 220 is connected to the database 210 and the diagnosis result display unit 230, and receives data other than the reference value from the database 210. The hot spot diagnosis unit 220 diagnoses whether or not a hot spot of the photovoltaic power generation array 20 configured in the photovoltaic power generation system 100 compares the solar equivalent operating time, the difference value, and the number of occurrences with a preset reference value, The diagnosis result may be transmitted to the diagnosis result display unit 230.

The diagnosis result display unit 230 displays the result of determining whether a hot spot of the photovoltaic array received from the hot spot diagnosis unit 220 occurs, and the result of estimating the power generation performance of the photovoltaic system or output data of the photovoltaic system. It may be a display device.

As shown in FIG. 2, the hot spot diagnosis unit 220 includes an equivalent operation time calculation unit 221, an equivalent operation time estimation unit 222, a loss estimator 223, and a hot spot determination unit 224. Consists of including.

The equivalent operating time calculation unit 221 is based on the solar equivalent operating time (Y _r,meas ) and the equivalent operating time measured value (Y _a,meas ) of the solar power array from the values of the inclined sunlight and DC power transmitted from the database 210. ) Is calculated using Equation 1.

[Equation 1]

In Equation 1 above, Y _r,meas is the solar equivalent operating time, G _a,meas is the insolation intensity on the slope (W/m ² ), and G _a,ref is the solar intensity 1,000 (W/m ² ), Y _a,meas Is the actual measured value of solar power array equivalent operating time, P _{a, meas} is the actual measured value of the solar power array DC power (W), and P _as is the installed capacity (W) of the solar power array under standard test conditions (STC).

In addition, the equivalent operating time calculation unit 221 includes the solar equivalent operating time (Y _{r, meas} ) calculated from Equation 1, the surface temperature (T _{m, meas} ) of the photovoltaic array received from the database 210, and the solar energy. From the direct current (I _a,meas ) of the photovoltaic array, the optimal equivalent operating time (Y _ao,meas ) of the photovoltaic array and the equivalent operating time (Y _at,meas ) after temperature correction of the photovoltaic array are calculated using Equation 2. It is calculated using

[Equation 2]

In Equation 2 above, Y _ao,meas are the actual measured value of the optimal equivalent operating time of the solar power array, Y _at,meas are the actual measured value of the equivalent operating time after temperature correction of the solar power array, and I _a,meas are the solar power array DC Current measured value, T _m,meas is measured surface temperature of photovoltaic array, R _a is photovoltaic array DC line resistance, α _m is photovoltaic array maximum performance factor, α _t is photovoltaic array temperature correction factor to be.

The equivalent operating time estimating unit 222 uses the solar equivalent operating time (Y _r,meas ) and the surface temperature (T _m,meas ) of the photovoltaic array, and uses the direct current of the photovoltaic array in consideration of aging according to the number of operating years. Voltage estimate (V _a,esti ), optimal equivalent operating time estimate of the photovoltaic array (Y _ao,esti ), equivalent operating time estimate after temperature correction of the photovoltaic array (Y _at,esti ), and The equivalent operating time estimate (Y _a,esti ) is calculated using Equation 3.

[Equation 3]

In Equation 3 above, Y _ao,esti is an estimate of the optimal operating time of the solar power array, Y _at,esti is the estimated value of the equivalent operating time after temperature correction of the solar power array, and Y _a,esti is the equivalent operating time of the solar power array. Estimated value, V _a,esti is the estimated value of the photovoltaic array DC voltage, D _v,aging is the photovoltaic array voltage aging factor, O _year is the operating years, R _a is the PV array DC line resistance, α _m is the solar power Power generation array maximum performance factor, α _t is the photovoltaic array temperature correction factor, a _t , b _t is the photovoltaic array temperature coefficient, a _v , b _v is the photovoltaic array voltage correction factor, and N _series is the photovoltaic power generation. This is the number of serial modules.

The loss estimating unit 223 uses Equation 4 from the measured values (Y _ao,meas , Y _at,meas ) of the equivalent operating time calculated in Equations 1 to 2, and the measured value of the mismatch loss of the photovoltaic array ( Y _lm,meas ) is calculated.

At this time, the loss estimating unit 223 calculates the actual measurement value (Y _lm,meas ) of the mismatch loss of the photovoltaic power generation array caused by serial and parallel imbalance of the photovoltaic power generation array and the maximum output point fluctuation, for 10 minutes or 15 minutes. Each period can be calculated using Equation 4, and the period is not limited.

[Equation 4]

In Equation 4 above, Y _ao,meas are the actual measured value of the optimal equivalent operating time of the solar power array, Y _at,meas are the actual measured value of the equivalent operating time after temperature correction of the solar power array, and Y _lm,meas are the solar power array mismatch. It is the measured value of loss.

The loss estimating unit 223 uses Equation 5 from the estimated values of the equivalent operating time (Y _ao,esti , Y _at,esti ) calculated in Equation 3 to estimate the mismatch loss of the photovoltaic array (Y _lm,esti ) Yields

The loss estimating unit 223 may calculate the estimated value (Y _lm,esti ) of the mismatch loss of the photovoltaic array using Equation 5 every 10 minutes or 15 minutes, and does not limit the period.

[Equation 5]

In Equation 5 above, Y _ao,esti is the estimated value of the optimal equivalent operating time of the photovoltaic array, Y _at,esti is the estimated value of the equivalent operating time after temperature correction of the photovoltaic array, and Y _lm,esti is the estimated value of the photovoltaic array mismatch loss. to be.

The hot spot determination unit 224 is between the measured mismatch loss of the photovoltaic array calculated from Equations 1 to 5 (Y _lm,meas ) and the estimated mismatch loss of the photovoltaic array (Y _lm,esti ). The difference between the PV array mismatch loss difference (Y _lm,resi ) is the difference between the PV array DC voltage measured value (V _a,meas ) and the solar PV array's DC voltage estimated value (V _a,esti ). Is calculated using Equation 6 as the difference value (V _a,resi ) of the direct current voltage of the photovoltaic array.

In this case, the actual measured value of the solar power array DC voltage (V _{a, meas} ) is the DC voltage value received from the database 210 from the solar power inverter 30.

[Equation 6]

In Equation 6 above, Y _lm,resi is the photovoltaic array mismatch loss difference value, V _a,resi is the photovoltaic array DC voltage difference value, Y _lm,meas is the measured photovoltaic array mismatch loss, Y _{lm ,esti} is the solar photovoltaic array mismatch loss estimate, V _a,meas is the photovoltaic array DC voltage measured value, and V _a,esti is the photovoltaic array DC voltage estimate.

The hot spot determination unit 224 compares the calculated solar equivalent operating time (Y _r,meas ) and the calculated difference values (Y _lm,rsei , V _{a, resi} ) with a preset reference value, and a set reference value Is satisfied, a diagnostic result that determines that a hot spot has occurred in the photovoltaic array is generated, and when the calculated solar equivalent operating time and the calculated difference values do not satisfy a preset reference value, the photovoltaic array is A diagnosis result that determines that no hot spot has occurred is generated, and each result is transmitted to the diagnosis result display unit 230.

In one example, the hot spot determination unit 224 compares the solar equivalent operating time (Y _r,meas ) with a reference value of 0.2, and compares the solar power array mismatch loss difference value (Y _{lm, resi} ) to the reference value A (- 0.06), and the photovoltaic array DC voltage difference value (V _a,resi ) compared to the reference value B (-0.1), and the number of occurrences (Freq) satisfying both the solar equivalent operating time and the comparison result of the difference values at the same time. .) is compared with the reference value C(8) to determine whether a hot spot has occurred.

The hot spot occurrence determination unit 224 counts the number of occurrences per day (Freq.) starting at midnight, and determines whether or not a hot spot occurs according to the conditional statement in Equation 7.

[Equation 7]

If (Y _r,meas >= 0.2 and Y _lm,resi <A and V _a,resi> B and Freq. >C)

delete

Hot spot occurrence;

Else

No hot spot;

End

In Equation 7 above, the reference values A, B, and C may be set within the ranges described above, but these may be changed, but are not limited thereto.

5 is an estimate of mismatch loss (Y _lm,esti ) of a photovoltaic array estimated by a hot spot diagnosis apparatus and method of a photovoltaic array according to an embodiment of the present invention and an estimate of the equivalent operating time of the photovoltaic array. (Y _a,resi ) as a normalization graph of the solar power equivalent operating time loss yield (pu) over time (minutes), and the measured mismatch loss of the photovoltaic array shown in FIG. 4 (Y _{lm, meas} ) and It can be seen that the graph, shape, and value of the actual measured value (Y _a,meas ) of the solar photovoltaic array are similar before 11:00 and after 15:30, and from 11:00 to 15: At 30 o'clock, it can be seen that the estimated mismatch loss (Y _lm,esti ) and the measured value (Y _lm,meas ) of the photovoltaic array are different, and the difference is less than the reference value A, -0.06. In addition, this indicates that the hot spot diagnosis apparatus of the photovoltaic array according to an embodiment of the present invention satisfies Equation 7 as the difference between the measured value and the estimated value of the mismatch loss of the photovoltaic array is calculated to be smaller than the reference value A. Show.

And, in the graph of the photovoltaic power generation system output voltage (V) according to the time (minute) shown in FIG. 6, the photovoltaic power generation array calculated by the hot spot diagnosis apparatus of the photovoltaic power generation array according to an embodiment of the present invention. It can be seen that the actual measured value of the DC voltage is greater than the estimated DC voltage of the photovoltaic array before 11:00 and after 15:30, and between 11:00 and 15:30, the direct current of the photovoltaic array It can be seen that the voltage measured value is smaller than the estimated DC voltage value of the photovoltaic array, and the difference is greater than the reference value B, 0.1. This means that the hot spot diagnosis apparatus of the photovoltaic array according to an embodiment of the present invention is It indicates that Equation 7 is satisfied by calculating the difference between the measured value and the estimated value of the mismatch loss of the photovoltaic array larger than the reference value B.

In addition, the difference value of the mismatch loss of the photovoltaic array calculated by the hot spot diagnostic device of the photovoltaic array according to an embodiment of the present invention and the difference between the measured value and the estimated value of the direct current voltage of the photovoltaic array are Like a graph that normalizes the difference value and yield (pu) of the solar power generation system according to the time (minute) shown in Figure 7, the difference between the final measured value and the estimated value obtained through the calculation process is from 11:00 to 15:30. It can be seen that the number of occurrences (Freq.) satisfying the case that is smaller than the reference value A, -0.06 and larger than the reference value B, 0.1, exceeds the reference value C, 8.

As such, from the graphs of FIGS. 4 to 7, the difference value calculated from the measured values and estimated values of the solar power generation system in the hot spot diagnosis apparatus of the solar power array according to an embodiment of the present invention is a reference value ( It is confirmed that A, B, C) is satisfied, and accordingly, the hot spot diagnosis apparatus of the solar power array according to an embodiment of the present invention uses the difference between the measured value and the estimated value to determine the hot spot of the solar power array. It is possible to accurately diagnose whether a spot occurs.

In this way, the hot spot determination unit 224 forming the hot spot diagnosis unit 220 of the hot spot diagnosis apparatus 200 includes an equivalent operation time calculation unit 221, an equivalent operation time estimation unit 222, and a loss weight. From the values calculated by the government 223, the difference value of the PV array mismatch loss (Y _{lm, resi} ) and the difference value of the PV array DC voltage (V _{a, resi} ) are calculated, and the solar equivalent operating time and the difference value As the hot spot is determined by comparing them with the reference value, it is possible to diagnose the hot spot of the photovoltaic array from a remote location without diagnosing the hot spot of the photovoltaic array using the equipment, so that the system can be operated effectively. , There is an effect of improving the maintenance time and cost of the solar power system.

The method of diagnosing the hot spot of the photovoltaic array in the hot spot diagnosis apparatus 200 of the photovoltaic power generation array will be described with reference to FIG. 3. First, the equivalent operating time calculation unit 221 uses Equation 1 Then calculate the solar equivalent time (Y _r,meas ) and the measured value of the solar power array's equivalent operating time (Y _{a, meas} ) (S10), and use Equation 2 to calculate the optimal equivalent operating time of the photovoltaic array. After (Y _ao,meas ) and temperature correction of the photovoltaic array, the equivalent operating time measured value (Y _at,meas ) is calculated (S20).

Then, the equivalent operating time estimating unit 222 uses Equation 3 to estimate the DC voltage of the photovoltaic array in consideration of aging according to the number of operating years (V _a,esti ), and the optimal equivalent operating time estimate of the photovoltaic array ( Y _ao,esti ), the estimated equivalent operating time (Y _at,esti ) after temperature correction of the photovoltaic array, and the estimated equivalent operating time (Y _a,esti ) of the photovoltaic array are calculated (S30).

Next, the loss estimating unit 223 calculates the solar photovoltaic array mismatch loss measured value (Y _lm,meas ) and the solar photovoltaic array mismatch loss estimate (Y _lm,esti ) using Equations 4 and 5. Do (S40).

In addition, the hot spot determination unit 224 calculates the solar power array mismatch loss difference value (Y _{lm, resi} ) and the photovoltaic array DC voltage difference value (V _{a, resi} ) using Equation 6 ( S50), the solar equivalent operating time (Y _r,meas ) and the difference values (Y _lm,rsesi , V _{a, resi} ) determine whether the set criteria are satisfied as in Equation 7 (S60), and if they are satisfied _{, the hot} spot is It is determined that it has occurred (S70), and if the criteria are not satisfied in the above step (S60), it is determined that the hot spot has not occurred (S80).

Although the embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements by those skilled in the art using the basic concept of the present invention defined in the following claims are also provided. It belongs to the scope of rights.

100: photovoltaic system 200: hot spot diagnostic device
210: database 220: hot spot diagnostic unit
221: equivalent operating time calculation unit 222: equivalent operating time estimation unit
223: Loss estimation unit 224: Hot spot determination unit
230: diagnosis result display unit 240: memory

Claims (10)

The actual measured value of the mismatch loss of the photovoltaic array is calculated from the solar equivalent operating time, the equivalent operating time of the solar power array, the optimal equivalent operating time of the solar power array, and the equivalent operating time after temperature correction of the solar power array, Considering the aging according to the number of operating years, the estimated DC voltage of the photovoltaic array reflecting the number of solar photovoltaic modules in series, the estimated optimal equivalent operating time of the photovoltaic array, the estimated equivalent operating time after temperature correction of the photovoltaic array, and the solar A loss estimating unit for calculating an estimated value of the mismatch loss of the photovoltaic array from the estimated value of the equivalent operating time of the photovoltaic array; And,
Calculate the difference value of the photovoltaic array mismatch loss from the measured value of the mismatch loss of the photovoltaic array calculated by the loss estimating unit and the estimated value of the mismatch loss of the photovoltaic array, and the calculated photovoltaic array mismatch loss Including; comparing the difference value with a set reference value and determining whether a hot spot has occurred in the photovoltaic array when the number of times that the reference value is satisfied exceeds the set value,
The hot spot generation is the solar equivalent operating time, the difference value of the PV array mismatch loss for the measured value and the estimated value of the PV array mismatch loss, the PV array DC for the measured value of the PV array DC voltage and the estimated value. A hot spot diagnosis apparatus of a solar photovoltaic array, characterized in that the determination is made by reflecting a voltage difference value, and a number of comparison results with respective standards set for each of the solar equivalent operating time and the difference values. The method of claim 1,
The solar equivalent operating time, the equivalent operating time of the photovoltaic power generation array, the optimum equivalent operating time of the photovoltaic power generation array, and the equivalent operating time after temperature correction of the photovoltaic power generation array are calculated and provided to the loss estimation unit. Operation time calculation unit; And,
From the solar equivalent operating time and the surface temperature of the photovoltaic array, the estimated DC voltage of the photovoltaic array considering aging according to the number of operating years, the optimal equivalent running time of the photovoltaic array, and the photovoltaic array. The hot spot diagnosis of a photovoltaic power generation array, further comprising: an equivalent operating time estimation unit that calculates an equivalent operation time estimate value after temperature correction and an equivalent operation time estimate value of the photovoltaic array and provides the loss estimation unit to the loss estimation unit. Device. ◈ Claim 3 was abandoned upon payment of the set registration fee. The method of claim 2,
The equivalent operation time calculation unit after correction of the solar equivalent operation time, the equivalent operation time of the photovoltaic array, the optimum equivalent operation time of the photovoltaic power generation array, and the temperature of the photovoltaic power generation array from Equations 1 and 2 below. A hot spot diagnosis device of a photovoltaic array, characterized in that calculating the equivalent operating time.
[Equation 1]

[Equation 2]

(At this time, Y _r,meas is the solar equivalent operating time, G _a,meas is the insolation intensity on the slope (W/m ² ), G _a,ref is the insolation intensity 1,000 (W/m ² ), and Y _a,meas is the solar power Actual measurement of power generation array equivalent operating time, P _a,meas is the solar photovoltaic array DC power (W), P _as is the solar photovoltaic array installation capacity (W) under standard test conditions (STC), and Y _ao,meas is solar Photovoltaic array optimal equivalent operating time measured value, Y _at,meas is the equivalent operating time measured value after photovoltaic array temperature correction, T _m,meas is the measured surface temperature of the photovoltaic array, and I _a,meas are solar photovoltaic power generation. Array DC current measured value, α _m is the solar photovoltaic array maximum performance factor, α _t is the photovoltaic array temperature correction factor, and R _a is the photovoltaic array DC line resistance.) ◈ Claim 4 was abandoned upon payment of the set registration fee. The method of claim 2,
The equivalent operating time estimating unit is the DC voltage estimation value of the photovoltaic power generation array taking into account aging according to the operating years from Equation 3 below, the optimal equivalent operating time estimation value of the photovoltaic power generation array, and the equivalent after temperature correction of the photovoltaic power generation array. An apparatus for diagnosing a hot spot of a photovoltaic array, characterized in that calculating an estimated operating time and an estimated equivalent operating time of the photovoltaic array.
[Equation 3]

(At this time, Y _ao,esti is the estimated value of the optimal operating time of the solar power array, Y _at,esti is the estimated value of the equivalent operating time after temperature correction of the photovoltaic array, Y _a,esti is the estimated value of the equivalent operating time of the solar power array, V _a,esti is the estimated value of the photovoltaic array DC voltage, D _v,aging is the photovoltaic array voltage aging factor, O _year is the number of operating years, I _a,meas is the actual measured value of the photovoltaic array DC current, and R _a is PV array DC line resistance, α _m is PV array maximum performance factor, α _t is PV array temperature correction factor, a _t , b _t is PV array temperature coefficient, a _v , b _v is solar Photovoltaic array voltage correction factor, N _series is the number of solar photovoltaic modules in series, N _parallel is the number of _parallel photovoltaic strings, Y _r,meas is the solar equivalent operating time, T _m,meas is the measured surface temperature of the photovoltaic array. .) The method of claim 1,
The loss estimating unit calculates the measured value of the mismatch loss of the photovoltaic array using Equation 4 below.
[Equation 4]

(At this time, Y _ao,meas are the measured value of the optimal equivalent operating time of the solar power array, Y _at,meas are the actual measured value of the equivalent operating time after temperature correction of the solar power array, and Y _lm,meas are the actual measured values of the solar power array mismatch loss. .) The method of claim 1,
The loss estimation unit calculates an estimated value of the mismatch loss of the photovoltaic array using Equation 5 below.
[Equation 5]

(At this time, Y _ao,esti is an estimate of the optimal equivalent operating time of the solar power array, Y _at,esti is an estimate of the equivalent operating time after temperature correction of the solar power array, and Y _lm,esti is an estimate of the solar power array mismatch loss.) ◈ Claim 7 was abandoned upon payment of the set registration fee. The method of claim 3,
The hot spot determination unit calculates a difference between the measured value of the mismatch loss of the photovoltaic array and the estimated value of the mismatch loss of the photovoltaic array from Equation 6 below as the difference value of the photovoltaic array mismatch loss. And calculating a difference between the actual measured value of the photovoltaic array DC voltage and the estimated value of the direct current voltage of the photovoltaic array as the difference value of the direct current voltage of the photovoltaic array.
[Equation 6]

(At this time, Y _lm,resi is the solar photovoltaic array mismatch loss difference value, Y _lm,meas is the measured photovoltaic array mismatch loss, Y _lm,esti is the solar photovoltaic array mismatch loss estimate, and V _a,resi is solar Photovoltaic array DC voltage difference value, V _a,meas are PV array DC voltage measured values, V _a,esti are PV array DC voltage estimates) ◈ Claim 8 was abandoned upon payment of the set registration fee. The method of claim 7,
The hot spot determination unit compares the solar equivalent operating time with a reference value of 0.2, compares the difference value of the photovoltaic array mismatch loss with the reference value A, compares the difference value of the photovoltaic array DC voltage with the reference value B, and The number of occurrences (Freq.) in which the comparison result of the equivalent operating time and difference values are all satisfied at the same time is judged whether or not a hot spot occurs from the result of the final comparison with the reference value C.
A hot spot diagnostic device for a photovoltaic array, characterized in that it determines whether or not a hot spot of the photovoltaic array occurs according to Equation 7 below.
[Equation 7]
If (Y _r,meas >= 0.2 and Y _lm,resi <A and V _a,resi> B and Freq. >C)
Hot spot occurrence;
Else
No hot spot;
End
(At this time, Y _r,meas are solar equivalent operating time, Y _lm,resi are solar photovoltaic array mismatch loss difference value, and V _a,resi are photovoltaic array DC voltage difference value.) ◈ Claim 9 was abandoned upon payment of the set registration fee. The method of claim 8,
The reference value A is -0.06, the reference value B is -0.1, and the reference value C is 8. Calculating an equivalent operating time of the photovoltaic array;
Calculating an optimal equivalent operating time of the photovoltaic array and the equivalent operating time after temperature correction of the photovoltaic array;
It calculates the DC voltage estimate value of the photovoltaic power generation array reflecting the number of series of photovoltaic power modules taking into account aging according to the operating years, the optimal equivalent operating time estimate value of the photovoltaic power generation array, and the equivalent operating time estimate value after temperature correction of the photovoltaic power generation array. step;
Calculating an actual measurement value of the photovoltaic array mismatch loss and an estimated value of the photovoltaic array mismatch loss;
Calculating a photovoltaic array mismatch loss difference value and a photovoltaic array direct current voltage difference value;
PV array mismatch loss difference value and photovoltaic array DC voltage difference value for the measured value and estimated value of the PV array mismatch loss, solar equivalent operating time, Determining whether each set criterion is satisfied for each number of times the photovoltaic array mismatch loss difference value satisfies a set criterion; And,
When the criteria set for each solar equivalent operation time, the difference values, and the number of times are satisfied, it is determined that a hot spot occurs, or when the criteria set for each of the solar equivalent operation time, the difference values, and the number of times are not satisfied. Determining that the hot spot does not occur; Hot spot diagnosis method comprising a photovoltaic array.

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