KR20140127930A - Solar photovoltaic power generation system - Google Patents

Abstract

The present invention relates to a photovoltaic power generation system having a monitoring function of a photovoltaic module in consideration of external environmental factors. A solar photovoltaic generation system according to a preferred embodiment of the present invention is a solar photovoltaic generation system having a solar photovoltaic module monitoring function considering external environmental factors, Wherein the diagnostic unit determines whether the voltage value of the solar module to be diagnosed included in the solar array is less than or equal to a first reference value and if the voltage value of the solar module to be diagnosed is equal to or less than the first reference value Determining whether the voltage value of the solar module to be diagnosed is equal to or less than the average value of the total solar array array and if the voltage value of the solar module to be diagnosed is less than the average value of the total solar array array, Judged that there is an abnormality in the optical module; And a reference value setting unit for setting the first reference value in consideration of external environmental factors.

Description

SOLAR PHOTOVOLTAIC POWER GENERATION SYSTEM WITH MONITORING SOLAR PHOTOVOLTAIC MODULE CONSIDERING EXTERNAL ENVIRONMENTAL FACTORS [0002]

The present invention relates to a solar power generation system, and more particularly, to a solar power generation system having a solar cell module monitoring function in consideration of external environmental factors.

Photovoltaic power generation is a way to convert light energy from the sun directly into electrical energy. The solar power generation system has a clean and unlimited energy source, it can generate only the necessary amount in necessary places, it is easy to maintain and unmanned, it can be longevity more than 20 years, The photovoltaic power generation system is increasing in proportion to the total power generation.

At the core of this solar power generation is a solar cell with a pn junction structure. When a photon is absorbed from the outside into the inside of a solar cell, the energy of the photon causes a pair of electrons and holes . The generated electron-hole pairs are transferred to the n-type semiconductor by the electric field generated at the pn junction, and the holes are transferred to the p-type semiconductor and collected at the electrodes on the respective surfaces. The charge collected at each electrode is a source of energy that operates the load as a current flowing through the load when a load is connected to an external circuit.

The smallest unit of solar cell is called cell. Actually, the solar cell is rarely used as it is. The reason for this is two, one is that the voltage from one cell is very small, about 0.5V, and the voltage actually used is several tens or hundreds of volts or more from several volts, so that several cells or dozens of cells are connected in series You must do it. Another reason is that when used outdoors, it is subjected to various harsh environments, so it is necessary to protect the connected cells in a harsh environment. For this reason, a plurality of cells are referred to as solar modules. In addition, a plurality of these modules are suitably used for the purpose of use, which is called a solar array.

In the case of large-scale photovoltaic power generation, several hundreds or more solar arrays are installed. When operating such large-scale solar power generation, the voltage of a specific solar array is lowered (in other words, the efficiency of a specific array is lowered), the voltage of a specific solar module is lowered Can be reduced).

Such efficiency degradation can be caused by shade, contamination, or failure. In general, the solar power generation system is installed in a place where there is sufficient sunlight and space is sufficient. Therefore, it can be seen that the shade of the cause of the decrease in efficiency is caused by the cloud, and the contamination is caused by the accumulated dust on the entire surface of the solar array for a long time, and the failure is caused by the deterioration of the cell.

When the efficiency deterioration of the solar array exceeds the threshold value, it is necessary to separate the solar array from the system in order to prevent the defective power source from being supplied to the system.

In addition, the operator immediately recognizes the cause of the efficiency deterioration, and it is necessary to be able to take measures such as repair, replacement, and cleaning for the specific module in which the efficiency deteriorates.

However, in the past, there was no solar power generation system capable of monitoring the cause of the efficiency reduction by dividing it into shade, pollution, and failure.

Further, there was no solar power generation system capable of separating the solar array whose efficiency deterioration exceeded the threshold value from the system.

In addition, in a conventional solar power generation monitoring system, a ZigBee module for sensing a voltage for each of a plurality of solar modules is installed in order to individually monitor a plurality of solar modules disposed in the solar array. At this time, since the ZigBee module is installed as many as the number of solar modules, there is a problem that the monitoring system is expensive, the monitoring system is complicated, and a lot of manpower is consumed in the installation process.

In addition, the conventional solar power generation monitoring system does not diagnose the solar module in consideration of external environmental factors, for example, the amount of sunlight and the temperature of the solar module, and thus the solar module can not be accurately diagnosed.

Accordingly, it is an object of the present invention to provide a solar power generation system capable of separating a solar array from a system in order to prevent a bad power from being supplied to the system when the efficiency deterioration of the solar array exceeds a threshold value.

The present invention provides a photovoltaic power generation system capable of taking measures such as repair, replacement, and cleaning for a specific module in which the operator immediately recognizes the cause of the efficiency degradation of the photovoltaic module.

The present invention also provides a photovoltaic power generation system capable of monitoring the cause of the decrease in efficiency as shade, contamination, and failure.

In addition, the present invention provides a solar power generation system capable of monitoring a plurality of solar modules individually using one ZigBee module installed for each solar array.

The present invention also provides a photovoltaic power generation system capable of monitoring a leakage current for each photovoltaic module.

The present invention also provides a photovoltaic power generation system capable of diagnosing a photovoltaic module in consideration of external environmental factors such as the amount of sunshine and the temperature of the photovoltaic module.

Other objects of the present invention will become readily apparent from the following description of the embodiments.

According to an aspect of the present invention, there is provided a photovoltaic generation system having a monitoring function of a photovoltaic module in consideration of an external environmental factor, the photovoltaic generation system including at least one And the diagnostic unit determines whether the voltage value of the solar module to be diagnosed included in the solar array is less than or equal to a first reference value, Determines whether or not the voltage value of the solar module to be diagnosed is equal to or less than the average value of the solar array, if the voltage value of the solar module to be diagnosed is less than the average value of the total solar array, Determining that there is an abnormality in the diagnosis target solar module if it is determined that the average value is less than the average value; And a reference value setting unit for setting the first reference value in consideration of external environmental factors.

Here, the diagnosis unit may determine that the diagnosis target solar module is normal if it is determined that the voltage value of the solar module to be diagnosed exceeds the overall average value of the solar array.

The diagnosing unit may be configured such that the voltage value of the solar module to be diagnosed is equal to or less than a total average value of the solar array including the diagnostic module and the voltage value of all the solar modules adjacent to the solar module If it exceeds the first reference value, it can be determined that the diagnosis target solar module is defective.

When the voltage value of at least one of the solar modules adjacent to the solar module to be diagnosed is equal to or less than the first reference value and the voltage reduction rate of the solar module to be diagnosed is equal to or less than the second reference value, It can be judged that the target solar module is contaminated.

The diagnosis unit may determine that a shadow has occurred in the diagnosis target solar module when the voltage reduction rate of the diagnosis target solar module exceeds the second reference value.

When the voltage value of the solar module to be diagnosed exceeds a total average value of the solar array and the rate of decrease of the average value of the solar array is equal to or less than a third reference value, It can be judged that the contamination occurs in the solar array including the solar array.

The diagnosis unit may determine that a shadow has occurred in the solar array including the solar module to be diagnosed when the rate of decrease of the total average value of the solar array exceeds the third reference value.

The reference value setting unit may set the first reference value using at least one of the temperature and the illuminance in the diagnosis target solar module and the output voltage characteristics of the diagnosis target solar module.

As described above, according to the present invention, when the efficiency deterioration of the solar array exceeds a threshold value, the solar array can be separated from the system in order to prevent a faulty power source from being supplied to the system.

In addition, the present invention divides the cause of the efficiency reduction of the photovoltaic module into faults, shadows, and dirts and informs the operator that the operator immediately takes measures such as repair, replacement, and cleaning .

In addition, the solar array and the ZigBee module are integrated with each other, so that it is possible to prevent the inconvenience of installing the ZigBee module separately. If the solar array and the ZigBee module are integrally formed, the identification number of the ZigBee module may be changed according to the installation position of the solar array. Therefore, it is necessary to give the identification number of the ZigBee module after installation of the solar array. The present invention enables the ZigBee module to be set wirelessly even if the solar array and the ZigBee module are integrally manufactured, thereby avoiding the troublesomeness associated with the setting of the ZigBee module located on the back surface of the solar array.

Further, according to the present invention, the voltage values of a plurality of solar modules are collected into one packet and transmitted to the central management unit, thereby minimizing the load on the ZigBee module and the central management unit according to packet transmission / reception.

Further, according to the present invention, a plurality of solar modules can be individually monitored using one ZigBee module installed for each solar array.

In addition, the present invention can monitor the leakage current for each solar module.

In addition, the present invention can diagnose a solar module in consideration of external environmental factors such as the amount of sunshine and the temperature of the solar module.

1 is a schematic diagram of a solar power generation system according to a preferred embodiment of the present invention.
Fig. 2 shows a rear view of the solar array of Fig. 1. Fig.
FIG. 3 shows a functional block diagram of the ZigBee module of FIG. 2. FIG.
4 shows a packet transmitted from the ZigBee module to the central management unit.
5 is a functional block diagram of the central management unit.
6 shows a data structure stored in the database of Fig.
FIG. 7 shows an operation flowchart of the array management unit of FIG. 5;
Fig. 8 shows an operation flow chart of the diagnosis unit of Fig. 5; Fig.

While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail. It should be understood, however, that the invention is not intended to be limited to the particular embodiments, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

Like reference numerals are used for like elements in describing each drawing. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

The terms first, second, etc. may be used to describe various components, but the components should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another.

For example, without departing from the scope of the present invention, the first component may be referred to as a second component, and similarly, the second component may also be referred to as a first component.

And / or < / RTI > includes any combination of a plurality of related listed items or any of a plurality of related listed items.

It is to be understood that when an element is referred to as being "connected" or "connected" to another element, it may be directly connected or connected to the other element, .

On the other hand, when an element is referred to as being "directly connected" or "directly connected" to another element, it should be understood that there are no other elements in between.

The terminology used in this application is used only to describe a specific embodiment and is not intended to limit the invention.

The singular expressions include plural expressions unless the context clearly dictates otherwise. In the present application, the terms "comprises" or "having" and the like are used to specify that there is a feature, a number, a step, an operation, an element, a component or a combination thereof described in the specification, But do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or combinations thereof.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

Terms such as those defined in commonly used dictionaries are to be interpreted as having a meaning consistent with the contextual meaning of the related art and are to be interpreted as either ideal or overly formal in the sense of the present application Do not.

Hereinafter, a solar power generation system according to a preferred embodiment of the present invention will be described with reference to FIGS. 1 to 8. FIG.

1 is a schematic diagram of a solar power generation system according to a preferred embodiment of the present invention.

1, a photovoltaic power generation system includes solar arrays 1000a, 1000b and 1000c, a DC connection unit 2000, an inverter 3000, a central management unit 4000, a communication network 5000, switching units 6000a, 6000b, 6000c).

The solar array 1000a, 1000b, 1000c (collectively referred to as " 1000 ") may include at least one solar module 1100. For convenience of explanation, it is assumed that the solar array 1000 includes twelve (3 by 4) solar modules in total. The number of solar modules included in the solar array 1000 can be variously changed according to the needs of the designer. The solar module 1100 is composed of a plurality of cells connected in series, and can output a voltage by converting sunlight into electric energy. The solar array 1000 can output a voltage corresponding to the sum of the voltages of the plurality of solar modules 1100 connected in series. Hereinafter, the output voltage of the solar array 1000 in a normal state (shade, contamination, failure free state) is referred to as a steady state output voltage.

The output voltage (DC voltage) of the solar array 1000 is supplied to the DC connection unit 2000. The DC voltage supplied to the DC connection unit 2000 is converted from the inverter 3000 to the three-phase AC, .

Switching units 6000a, 6000b, and 6000c (hereinafter collectively referred to as " 6000 ") may be provided on a line L for supplying an output voltage of the solar array 1000 to the DC connection unit 2000. The switching unit 6000 may enable / disable the supply of the voltage from the solar array 1000 to the DC connection unit 2000 by performing the on / off operation under the control of the central management unit 4000. [ In addition, a diode may be provided on the line L for supplying the output voltage of the solar array 1000 to the DC connection unit 2000 to prevent reverse flow.

The central management unit 4000 can diagnose the module 1100 on the solar array 1000 through the communication network 5000. [ The central management unit 4000 can diagnose the cause of the decrease in the output voltage of the solar module 1100 as shade, contamination, or failure. The central management unit 4000 monitors the output voltage of the solar array 1000 and can stop the supply of the voltage of the solar array 1000 whose output voltage is lower than a preset value when the output voltage is lower than a predetermined value. The specific operation of the central management unit 4000 will be described later.

Here, the protocol constituting the communication network 5000 may be unlimited, and different types of communication networks may be merged to constitute the communication network 5000. The communication network 5000 may adopt at least one of a wired and wireless communication scheme.

Fig. 2 shows a rear view of the solar array of Fig. 1. Fig.

Referring to FIG. 2, one ZigBee module 1200 may be integrally installed on the rear surface of the solar array 1000. Since the ZigBee module 1200 is integrally installed in the solar array 1000 in the step of manufacturing the solar array 1000, there is no need to install the ZigBee module 1200 separately. However, if the ZigBee module 1200 is installed integrally at the stage of manufacturing the solar array 1000, the solar array 1000 is installed in a specific place, and then the ZigBee module 1200 is installed This can be difficult. Accordingly, the present invention enables the ZigBee module 1200 to be set wirelessly. Specific details will be described later. The present invention can provide one ZigBee module per photovoltaic array for cost reduction of the monitoring system, simplification of the system, and minimum manpower mobilization in the installation of the ZigBee module. 2 is only an example, and the installation position of the ZigBee module 1200 may be variable. Of course, the ZigBee module 1200 may be installed separately from the solar array 1000 as the case may be.

FIG. 3 shows a functional block diagram of the ZigBee module of FIG. 2. FIG.

3, the ZigBee module 1200 includes a communication unit 1210, a voltage measuring unit 1220, a voltage value providing unit 1230, a setting unit 1240, a storage unit 1250, a leakage current providing unit 1260 ).

The communication unit 1210 is equipped with a Zigbee (IEEE 802.15.4) and can communicate with the central management unit 4000 in a Zigbee manner. At this time, the repeater may be located between the communication unit 1210 and the central management unit 4000. [ Here, when only Zigbee is used as a communication method, the repeater may be a coordinator. On the other hand, when a Zigbee method and a heterogeneous communication protocol, for example, TCP / IP are mixed, the repeater communicates with the ZigBee module in a Zigbee manner and communicates with the central management part 4000 using a different communication protocol Can be performed.

The voltage measuring unit 1220 can measure an output voltage of each of the plurality of solar modules 1100 in a predetermined manner. 2, the + output terminal P and the output terminal N of each of the solar modules 1100 can be connected to the voltage measuring unit 1220 for measuring the voltage of each of the solar modules . 2 shows a state where the + output terminal P and the output terminal N of one solar module 1100 are connected to the ZigBee module 1200 for convenience of explanation. The + output terminal P and the - output terminal N of all the solar modules 1100 mounted on one solar array 1000 can be connected to the voltage measuring unit 1220 . To this end, the voltage measuring unit 1220 may include a channel so as to be connected to the + output terminal P and the - output terminal N by the predetermined number of solar modules. The voltage measuring unit 1220 can measure the voltage of each of the solar modules applied from the plurality of channels simultaneously or at a time. The measured voltage can be matched and stored with the solar module number. The voltage measuring unit 1220 measures the voltage of the solar module in the order of the solar module numbers, and stores the measured voltage value in correspondence with the solar module number.

The voltage value providing unit 1230 may provide the voltage value measured by the voltage measuring unit 1220 to the central managing unit 4000 via the communication unit 1210. [ Details of packets transmitted from the voltage value provider 1230 to the central management unit 4000 in order to provide the voltage value to the central management unit 4000 will be described later.

The setting unit 1240 can wirelessly receive a control signal from a wireless terminal (not shown) carried by the operator and set the ZigBee module 1200. The operator can transmit the identification number corresponding to the unique number (for example, the serial number) of each ZigBee module 1200 to the setting unit 1240 through the wireless communication method in order to set the ZigBee module 1200 . The setting unit 1240 receiving the number can store the identification number as the identification information of the ZigBee module 1200. The identification number can be set corresponding to the installation position of the solar array 1000. For example, when a plurality of solar arrays are arranged in 3 rows and 4 columns, a ZigBee module corresponding to the solar array of row 1 and column 1 may be set to "1" or "11" as its identification number, The ZigBee module corresponding to the solar array of the row can be set to "7" or "23" as its identification number. As described above, the number in which the row number and the column number are listed can be used, and the number can be made in ascending order as the column number is added from the first row to the last row. In this way, the identification number of the ZigBee module is numbered corresponding to the installation position of the solar array, so that the ZigBee module, the solar module, and the solar array can be easily managed. Hereinafter, the identification number of the ZigBee module may be used in the same meaning as the solar array identification number.

The storage unit 1250 stores the information required for the ZigBee module 1200 to operate and the identification number as the setting information. The storage unit 1250 can store the voltage value of each solar module 1100 by matching with the solar module number.

The leakage current providing unit 1260 may provide the central management unit 4000 with the leakage current value in each of the solar modules by matching with the solar module identification information. The leakage current providing unit 1260 may supply the central management unit 4000 with a leakage current value matched to each solar module number in the packet of FIG. Alternatively, as shown in FIG. 4, the array number, the solar module number, and the leakage current value of each solar module matched to each solar module number can be created in a separate packet and transmitted to the central management unit 4000. The leakage current providing unit 1260 may be connected to the CT 1200 for measuring the leakage current of the output terminal of each of the photovoltaic modules. The CT 1200 is located at the output terminal of each of the photovoltaic modules, The CT 1200 may be implemented using a ZCT (Zero Current Transformer), and the CT 1200 may measure the leakage current value of the CT 1200 and provide the measured value to the leakage current providing unit 1260. Here, The output voltage and leakage current value of each of the photovoltaic modules can be measured simultaneously or at the same time. The solar module < RTI ID = 0.0 > The respective output voltages and the leakage current values can be transmitted to the central management unit 4000 in the same packet or different packets.

4 shows a packet transmitted from the ZigBee module to the central management unit. Referring to FIG. 4, a packet transmitted from the ZigBee module 1200 to the central management unit 4000 may include a Send ID field, a Receive ID field, an Array Number field, and at least one Module Number field and a Voltage field. Here, the Send ID field may be the identification information of the ZigBee module, and the Receive ID field may be the identification information of the central management unit 4000. And, the Array Number field may be the solar array identification number (or ZigBee module identification number) as seen above. The Module Number field can be the identification number of each solar module and the Voltage field can be the output voltage value of the solar module corresponding to each Module Number. When the ZigBee module 1200 transmits the voltage values of the plurality of solar modules 1100 to the central management unit 4000 in packets different from one another for each solar module, Packets may be very large and overload of the ZigBee module 1200 and the central management unit 4000 may occur. Therefore, the ZigBee module 1200 can generate a plurality of Module Numbers and voltage values corresponding to the Module Numbers, respectively, in one packet, and transmit them to the central management unit 4000. If the voltage value of all the modules included in one array can not be transmitted in one packet due to the number of solar modules installed in one array, it may be divided and transmitted. In some cases, the Module Number field may be omitted, and a bit value may be added to arrange the forward value in order of the photovoltaic module identification number and to distinguish the neighboring voltage value between the forward values. In addition, the packet may include time information in which the voltage value is sensed by the ZigBee module 1200. To this end, the ZigBee module 1200 may be provided with a timer synchronized with the central management unit 4000. As described above, the packet of FIG. 4 may include a leakage current value matched with each solar module number.

5 is a functional block diagram of the central management unit. The central management unit 4000 includes a communication unit 4100, a database management unit 4200, an array management unit 4300, a diagnosis unit 4400, an interface unit 4500, a database unit 4600, and a reference value setting unit 4700 .

The communication unit 4100 can perform communication with the ZigBee module 1200 or the switching unit 5000 according to a set protocol.

The database management unit 4200 can manage the database unit 4600. 6 shows a data structure stored in the database unit of FIG. As shown in FIG. 6, the database management unit 4200 obtains the solar array number, the solar module number matched to the solar array number, and the voltage value matched to the solar module number among the packets received from the ZigBee module 1200 6 can be stored in the form. At this time, the time information may be stored in matching with the array number. Here, the time information may be a time when the voltage value of the Zigbee module 1200 is sensed or a time when the central management unit 4000 receives the packet from the Zigbee module 1200.

The array management unit 4300 can control the permission / prohibition of the supply of the voltage from the solar array 1000 to the DC connection unit 2000. When the output voltage of the solar array 1000 is equal to or lower than a predetermined value, the array management unit 4300 turns off the switching unit 5000 located between the solar array and the DC connection unit 2000, The voltage supply of the solar array 1000 can be cut off.

Hereinafter, with reference to FIG. 7, a specific operation of the array management unit 4300 will be described. FIG. 7 shows an operation flowchart of the array management unit of FIG. 5;

Referring to FIG. 7, the array management unit 4300 may determine whether the solar array output voltage is below a predetermined first reference value (S101). The solar array output voltage can be calculated by summing the output voltage values of all the solar modules included in one solar array. At this time, as the output voltage value of the solar module, the voltage value created on the packet shown in Fig. 4 can be used. Alternatively, a separate voltage measurement element may be added to the solar array output, and the voltage value of the solar array may be obtained using the voltage value received from the voltage measurement element. However, it is desirable to calculate the output voltage of the solar array by the former method in order to minimize the installation cost and to minimize the packets used for monitoring. As a result of the determination in step S101, if the first reference value is less than or equal to the first reference value, the array management unit 4300 outputs a control signal to the switching unit 5000 to shut off the voltage supply to the solar array (S102). If the solar array output voltage is lower than the first reference value in the next diagnosis after the solar array is separated in the DC connection module 2000 in S102, the array management unit 4300 can maintain the solar array in a separated state, Otherwise, if the solar array output voltage exceeds the first reference value, the solar array may be connected to the DC connection unit 2000 again to allow the solar array to supply the voltage to the DC connection unit 2000 again (S103, S104). As a result of the determination in S101, if the solar array output voltage exceeds the first reference value, the array management unit 4300 can continuously connect the solar array to the DC connection unit 2000. [ Thereby, it is possible to prevent the output voltage of the solar array below the first reference value from being supplied to the power grid. The array management unit 4300 can inform the outside through the interface unit 4500 of the solar array that is equal to or less than the first reference value.

5, the diagnosis unit 4400 can diagnose each of the solar array and / or the photovoltaic module using the photovoltaic module voltage received from the ZigBee module 1200. [ The diagnosis unit 4400 can diagnose each of the solar array and / or the solar module sequentially in a predetermined order. The diagnosis unit 4400 can use the information shown in FIG. 6 stored in the database unit 4600 at the time of diagnosis. The information in Fig. 6 may include the leakage current value of each solar module matched with each solar module number. The diagnosis unit 4400 diagnoses the leakage current value of each of the photovoltaic modules and can provide an alarm when the leakage current value exceeds the preset value. The diagnosis unit 4400 can provide the manager with the solar module number in which the leakage current value exceeds the preset value when the alarm is provided.

The reference value setting unit 4700 can set the reference voltage value used for diagnosis of the photovoltaic module. The reference value setting unit 4700 can set the reference voltage value in consideration of external environmental factors such as the temperature and the amount of sunshine of the solar module at the time of diagnosis. To this end, the reference value setting unit 4700 can receive the temperature on each solar module and the illumination information on each solar array from the solar array side via the ZigBee module 1200 and the communication network 5000. The temperature information on each solar module can be created and received for each solar module in the packet of Fig. Alternatively, the packet of FIG. 4 may be received in a separate packet at the same time zone as the time when the packet is received. The illuminance information on each solar array can be created and received in the packet of Fig. Alternatively, the packet of FIG. 4 may be received in a separate packet at the same time zone as the time when the packet is received. To this end, a temperature sensor (not shown) is attached to the front surface of each solar module, and the temperature on the solar module can be detected using the temperature sensor. Also, an illuminance sensor (not shown) is attached to the front surface of the solar array, and the illuminance on the solar array can be detected using the illuminance sensor. The illuminance may differ depending on the position of the solar array. This is because a shadow may occur only in a specific corner area of the solar array. Therefore, it is preferable to attach an illuminance sensor to each of the four corners of the solar array and to set the reference voltage value using the maximum illuminance value among the illuminance values detected by the illuminance sensor. This is due to the fact that the use of low illuminance values results in very low resolution for detecting degraded photovoltaic modules.

The reference value setting unit 4700 can set the reference voltage value by correcting the predetermined basic reference voltage value using the temperature value of each solar module and the illuminance value of each solar array. The reference voltage value can be processed every time the PV module is diagnosed. The baseline reference voltage value may be, for example, the output voltage of the solar module when the general reference state, i.e., the temperature of the solar module is 25 占 폚 and the illuminance is 1000 W / m2. The output voltage change characteristics of the solar module according to the temperature change of the solar module and the output voltage change characteristics of the solar module due to the illumination change may be different according to the manufacturer of the solar module. Therefore, the reference value setting unit 4700 sets the output voltage change characteristic of the solar module according to the temperature change of the solar module of the previously stored solar module, and the output voltage change characteristic of the solar module according to the illumination change, 1 can be applied to calculate the reference transfer value.

[Equation 1]

Reference voltage value = basic reference voltage value * (1+ voltage increase rate with increasing or decreasing temperature) * (1+ voltage increasing rate with increasing or decreasing luminance)

For example, when the base voltage is 40 V, the temperature of the solar module is 60 캜, the illuminance of the solar module is 1200 W / m 2, and the output voltage of the solar module changes according to the temperature of the solar module , The output voltage of the photovoltaic module decreases by 20% compared to the baseline reference voltage when the temperature is 60 ° C. and the output voltage of the photovoltaic module increases by 5% depending on the characteristics of the output voltage change of the photovoltaic module Assuming that,

The reference voltage value may be 40 * (1-0.2) * (1 + 0.05) = 33.6V.

In contrast to the above, the reference voltage value according to the illuminance is stored for the date and time in the area where the corresponding photovoltaic module is located, and the reference voltage value matched at the diagnosis time at diagnosis can be used for diagnosis. Only one of the illuminance and the temperature may be considered for setting the reference voltage value.

When only the temperature is considered, the reference value setting unit 4700 can calculate the reference voltage value by referring to the output voltage change characteristic of the solar module according to the temperature change of the solar module of the corresponding stored solar module. For use of the reference value setting unit 4700, the output voltage information of the solar module per temperature section may be stored.

Alternatively, when only the illuminance is considered, the reference voltage value can be calculated by referring to the output voltage change characteristic of the solar module according to the change in the illuminance of the previously stored solar module. For use of the reference value setting unit 4700, the output voltage information of the solar module per illumination section may be stored.

Hereinafter, a specific operation of the diagnosis section 4400 will be described with reference to FIG. Fig. 8 shows an operation flow chart of the diagnosis unit of Fig. 5; Fig.

Referring to FIG. 8, the diagnosis unit 4400 can determine whether the voltage value of the solar module to be diagnosed is equal to or less than a predetermined first reference value (S1101). Here, the reference voltage value set by the reference value setting unit 4700 may be used as the first reference value. The reference voltage value may be set at each diagnosis of the diagnosis section 4400. [ The details of setting the reference voltage value are as described above. As a result of the determination in S1101, if it is determined that the voltage value of the solar module to be diagnosed exceeds the first reference value, the diagnosis unit 4400 determines whether or not the diagnosis of the solar array including the solar module to be diagnosed is completed (S1106). As a result of the determination in S1106, if it is determined that the diagnosis of the solar array including the target solar module is not completed, the diagnosis unit 4400 changes the solar module to be diagnosed (S1009) It is possible to perform S1101. As a result of the determination in S1106, if it is determined that the diagnosis of the solar array including the solar module to be diagnosed is completed, the diagnosis unit 4400 can determine whether the diagnosis of all the solar array is completed (S1107). As a result of the determination in S1107, if it is determined that the diagnosis for all the solar arrays is completed, the diagnosis unit 4400 can wait until the next diagnosis (S1108). Alternatively, if it is determined in step S1107 that the diagnosis for all the solar arrays is not completed, the diagnosis unit 4400 may change the solar array to be diagnosed (S1110). Then, the diagnosis unit 4400 can perform step S1101 for the solar module included in the changed solar array to be diagnosed.

If it is determined in step S1101 that the voltage value of the solar module to be diagnosed is lower than the first reference value, the diagnosis unit 4400 determines that the voltage value of the solar module to be diagnosed is equal to the average value of the solar array (For example, if the photovoltaic array includes twelve photovoltaic modules, the average value of the voltages of the twelve photovoltaic modules) (S1102). As a result of the determination in S1101, even if the value is equal to or less than the first reference value, the diagnosis target solar module can not be determined as a failure. This is because the decrease in the output voltage of the solar module to be diagnosed may be caused by shade or contamination. Therefore, it is necessary to precisely determine whether the cause of the output voltage drop is failure, shade, or contamination. As a result of the determination in S1102, if it is determined that the voltage value of the solar module to be diagnosed exceeds the overall average value of the solar array including the solar module, the diagnostic unit 4400 determines whether the decrease rate of the total average value is greater than a predetermined third reference value Or less (S1111). The reduction rate can be calculated using the information on FIG. 6 used in the current diagnosis and the information on the structure as shown in FIG. 6 collected just before the information collection. The unit time as a reference for the reduction rate calculation can be easily selected by the designer. As a result of the determination in S1111, if it is determined that the third reference value is exceeded, the diagnosis unit 4400 may determine that a shadow has occurred in the solar array including the solar module to be diagnosed (S1113). At this time, the diagnosis unit 4400 can inform the outside through the interface unit 4500 that a shadow has occurred in the solar array. Alternatively, if it is determined in step S1111 that the value is equal to or less than the third reference value, it may be determined that contamination has occurred in the solar array including the diagnostic target module (S1112). At this time, the diagnosis unit 4400 can inform the outside through the interface unit 4500 that contamination has occurred in the solar array, and at the same time can inform the outside that cleaning is required. The shade occurs when the sunlight is covered by the cloud, and the rate of decrease of sunlight per unit time is very large. On the other hand, the occurrence of contamination is caused by particles such as dust accumulating on the surface of the solar array due to prolonged exposure of the solar array to the outside, so that the rate of decrease of sunlight per unit time is very small. And, a decrease in sunlight can cause a decrease in the output voltage of the solar module or solar array, and the rate of decrease in output voltage per unit time can be different depending on whether it is contaminated or shaded. Accordingly, the rate of decrease of the average value of the solar array can be used to distinguish whether the solar array is contaminated or shaded. Diagnosis of the solar array unit may be possible through S1102, S1111, S1112, and S1113. When the diagnosis of the solar array including the solar panel module to be diagnosed is completed in S1101 because it is judged as being contaminated or shaded in S1112 and S1113, the diagnosis section 4400 judges whether the sunlight The diagnosis can be performed by changing the solar array to be diagnosed without proceeding to diagnosis for other solar modules included in the array (S1107, S1110). At this time, if the diagnosis of all the solar arrays is completed, the diagnosis unit 4400 can wait until the next diagnosis. The voltage value of the solar module to be diagnosed exceeds the total average value of the solar array including the module means that the total average value of the solar array is equal to or less than the first reference value. When the diagnosis is performed at regular intervals, the total average value of the solar array including the solar module to be diagnosed is equal to or less than the first reference value, which means that the problem of the solar module itself included in the solar array There is a high probability of overshadowing and contamination. Therefore, when the voltage value of the solar module to be diagnosed exceeds the total average value of the solar array including the solar module, the diagnosis is not made for the other solar modules, It is possible to prevent unnecessary diagnosis for other solar modules from proceeding.

As a result of the determination in S1102, if it is determined that the output voltage value of the solar module to be diagnosed is equal to or less than the overall average value of the solar array including the module, the diagnostic unit 4400 determines at least one of the solar modules adjacent to the solar module to be diagnosed It can be determined whether one voltage value is equal to or less than the first reference value (S1103). Here, the reference voltage value set by the reference value setting unit 4700 may be used as the first reference value. The reference voltage value may be set at each diagnosis of the diagnosis section 4400. [ The details of setting the reference voltage value are as described above. Here, neighboring means that when the position of the photovoltaic module is represented by rows and columns, the difference between the rows and the columns based on the row and column representing the position of the photovoltaic module to be diagnosed is within the range of "1" can do. As a result of the determination in S1103, if it is determined that the output voltage values of neighboring solar modules exceed the first reference value, it can be determined that the diagnostic target solar module is faulty (S1114). This is because the output voltage value of the neighboring solar module is in the normal range and the output voltage value of the solar module to be diagnosed is out of the normal range (lower than the first reference value).

As a result of the determination in S1103, if it is determined that at least one solar module of the neighboring solar modules is less than or equal to the first reference value, it may be determined whether the voltage reduction rate of the solar module to be diagnosed is less than a predetermined second reference value S1104). The probability of two neighboring solar modules failing at the same time is very low. Accordingly, when two or more neighboring solar modules are equal to or less than the first reference value, it is sufficient to judge whether the solar modules to be diagnosed are shaded or contaminated. As mentioned earlier, when the shade is generated, the voltage reduction rate is large, and when the pollution occurs, the voltage reduction rate may be small. Accordingly, if it is determined in step S1104 that the voltage reduction rate of the solar module to be diagnosed is lower than the second reference value, the diagnosis unit 4400 can determine that the solar module to be diagnosed is contaminated (S1105) If it is determined that the voltage reduction rate of the solar module to be diagnosed exceeds the second reference value, it can be determined that a shadow has occurred in the solar module to be diagnosed (S1115). When the diagnosis of the solar module to be diagnosed is completed in S1105, S1114, and S1115, the diagnosis unit 4400 can notify the diagnosis result through the interface unit 4500. [ At this time, the diagnostic unit 4400 can request the repair through the interface unit 4500 if the diagnosis result is faulty, and can request cleaning if the diagnosis result is contaminated. When the diagnosis of the solar module to be diagnosed is completed in S1105, S1114, and S1115, the diagnosis unit 4400 completes the diagnosis of the solar array including the solar module to be diagnosed, and the diagnosis of all the solar arrays is completed It is possible to change the solar array to be diagnosed and proceed to S1101 for the solar module on the changed solar array. Alternatively, if the diagnosis of the solar array including the solar module to be diagnosed is not completed, the diagnosis unit 4400 may change the solar module to be diagnosed and proceed to S1101.

As described above, the present invention can perform diagnosis for each solar array and / or for each solar module. The diagnostic result for each solar array and / or photovoltaic module may be stored in the database unit 4500. The process of Fig. 8 may be performed as a whole or as a part thereof. For example, S111, S1112, and S1113 may be omitted. Even if S111, S1112, and S1113 are omitted, it is possible to diagnose the entire solar array by repeatedly performing the diagnosis of each solar module. In this case, if it is determined in step S1102 that the total average value is exceeded, it can be determined that the solar module to be diagnosed is normal. In addition, S1103, S1104, S1105, S1114, and S1115 may be omitted. In this case, if it is determined as a result of the determination in S1102 that the value is equal to or less than the total average value, it is possible to notify that there is an abnormality in the solar module to be diagnosed. In this case, the malfunction, shade, or contamination is not automatically diagnosed, and the operator can directly identify the cause of the decrease in the output value of the target module by reading the corresponding solar module, and take measures accordingly.

As described above, according to the present invention, when the efficiency deterioration of the solar array exceeds the threshold value, the solar array can be separated from the system in order to prevent the faulty power from being supplied to the system.

In addition, the present invention divides the cause of the efficiency reduction of the photovoltaic module into faults, shadows, and dirts and informs the operator that the operator immediately takes measures such as repair, replacement, and cleaning .

In addition, the solar array and the ZigBee module are integrated with each other to prevent the inconvenience of installing the ZigBee module separately. When the solar array and the ZigBee module are integrally formed, the identification number (or the solar array identification number) of the ZigBee module corresponding to the solar array can be varied according to the installation position of the solar array. Therefore, it is necessary to give the identification number of the ZigBee module after installation of the solar array. The present invention enables the ZigBee module to be set wirelessly even if the solar array and the ZigBee module are integrally manufactured, thereby avoiding the troublesomeness associated with the setting of the ZigBee module located on the back surface of the solar array.

In addition, the present invention can minimize the load on the ZigBee module and the central management unit according to the packet transmission / reception by collecting the values of the plurality of solar modules as one packet and transmitting them to the central management unit.

The present invention can diagnose a solar module in consideration of external environmental factors such as the amount of sunshine and the temperature of the solar module.

It will be apparent to those skilled in the relevant art that various modifications, additions and substitutions are possible, without departing from the spirit and scope of the invention as defined by the appended claims. The appended claims are to be considered as falling within the scope of the following claims.

1000a, 1000b, 1000c: solar array
1100: Photovoltaic module
1200: ZigBee module
1210:
1220: voltage measuring unit
1230:
1240: Setting unit
1250:
1260: Leakage current supply
2000: DC connection board
3000: Inverter
4000: Central Management Department
4100:
4200:
4300:
4400:
4500: Interface part
4600:
4700: Reference value setting section
5000: Network
6000a, 6000b, 6000c:

Claims (8)

In a photovoltaic power generation system having a solar module monitoring function considering external environmental factors,
A diagnostic unit for performing diagnosis for each of at least one solar module included in the solar array; the diagnosis unit determines whether a voltage value of the solar module to be diagnosed included in the solar array is below a first reference value Determining whether a voltage value of the solar module to be diagnosed is equal to or less than a total average value of the solar array module when it is determined that the voltage value of the solar module to be diagnosed is equal to or less than the first reference value, Determining that the diagnostic target solar module is abnormal if the voltage value is determined to be equal to or less than the average value of the total solar array array; And
And a reference value setting unit for setting the first reference value in consideration of external environmental factors. The method according to claim 1,
Wherein the diagnosis unit comprises:
And determines that the diagnosis target solar module is normal if it is determined that the voltage value of the solar module to be diagnosed exceeds the overall average value of the solar array. The method according to claim 1,
Wherein the diagnosis unit comprises:
Wherein the voltage value of the solar module to be diagnosed is less than a total average value of the solar array including the diagnostic module,
When the voltage value of all the solar modules adjacent to the diagnosis target solar module exceeds the first reference value,
And determines that the diagnosis target solar module is malfunctioning. The method of claim 3,
Wherein the diagnosis unit comprises:
Wherein a voltage value of at least one of the solar modules adjacent to the solar module to be diagnosed is equal to or less than the first reference value,
When the voltage reduction rate of the solar module to be diagnosed is equal to or less than the second reference value,
And determines that contamination has occurred in the solar module to be diagnosed. 5. The method of claim 4,
Wherein the diagnosis unit comprises:
When the voltage reduction rate of the solar module to be diagnosed exceeds the second reference value,
And determines that a shadow has occurred in the diagnosis target solar module. The method according to claim 1,
Wherein the diagnosis unit comprises:
It is determined that the voltage value of the solar module to be diagnosed exceeds the total average value of the solar array,
When the reduction rate of the total average value of the solar array is equal to or less than the third reference value,
And determines that contamination has occurred in the solar array including the solar module to be diagnosed. The method according to claim 6,
Wherein the diagnosis unit comprises:
When the reduction rate of the total average value of the solar array exceeds the third reference value,
And determines that a shadow has occurred in the solar array including the diagnosis target solar module. The method according to claim 1,
Wherein the reference value setting unit comprises:
Wherein the first reference value is set using at least one of the temperature and the illuminance in the diagnosis target solar module and the output voltage characteristic of the diagnosis target solar module.

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