Diagnosis system for measuring string health of solar power generation system

Abstract

The present invention relates to a diagnosis system for measuring string health of a solar power generation system and, more specifically, to a diagnosis system for measuring string health of a solar power generation system, which calculates the string health by measuring a ratio of an actual amount of power generation to an expected amount of power generation for each string constituting the solar power generation system, and quickly detects an abnormal string through the string health, thereby supporting prompt action to be performed.

Description

Diagnostic system for measuring string health in solar power generation systems

[0001] The present invention relates to a diagnostic system for measuring the string health of a solar power generation system, and more particularly, to a diagnostic system for measuring the string health of a solar power generation system, which calculates the string health by measuring the ratio of the actual power generation amount to the expected power generation amount for each string constituting the solar power generation system, and supports the rapid detection of a string in which an abnormality has occurred through the string health amount, thereby enabling prompt action to be taken.

[0002] A solar power generation system may be configured to include a plurality of strings formed by connecting solar modules in series, a junction box connected in parallel, and an inverter that converts the generated power of each of the plurality of strings provided through the junction box into alternating current and provides it to the grid.

[0003] At this time, the strings constituting the solar power generation system generate electricity according to the following mathematical formula 1 depending on the amount of solar radiation incident on the solar module.

[0004]

[0005] At this time, the above P is the power generation amount (W) of the string, and the above A is the area (m) of the solar module (or one or more solar modules) constituting the string. 2 )(total area), and the above r is the efficiency (%) of the solar modules constituting the string, and the above I is the solar irradiance (W / m 2 ), and N is the number of serially connected solar modules constituting the string.

[0006] In the process of operating such a solar power generation system, differences in the amount of solar radiation incident on each solar module occur due to shading or settling of contaminants on the solar modules, or differences in the amount of power generated occur due to failure or deterioration of the solar modules, which results in differences in the amount of power generated between strings.

[0007] Accordingly, if there is a difference in power generation between strings connected to the inverter due to the circuit configuration of the inverter, the power generation of all strings will be affected by the power generation of the worst-performing string, and if this is left unattended, the power generation of the entire solar power generation system will continue to decline, resulting in a problem of loss of power generation from the solar power plant.

[0008] To solve this problem, the existing solar power generation monitoring system, as shown in Fig. 1, is connected to the output terminal of each string for each string and measures the maximum voltage (V) of the DC power output from the string. max ) and maximum current (I max ) and a controller that receives the measurement signal from the current-voltage analysis module, calculates the power generation amount based on the measurement signal, and detects a string in which an abnormality has occurred based on the measurement signal.

[0009] However, these existing solar power generation monitoring systems measure power not at the inverter but at the front of the junction box or in front of the inverter, so they cannot measure the power generation health of the string throughout the entire section from the module to the inverter, which reduces the accuracy and reliability of power generation measurement.

[0010] In addition, these existing solar power generation monitoring systems have a high level of complexity in configuring current-voltage analysis modules for each string, and because they directly measure the high-voltage power generated by the string, there is a high risk of damage to the current-voltage analysis modules, which requires continuous management of the current-voltage analysis modules, resulting in low management convenience and problems with reduced measurement accuracy and reliability when the current-voltage analysis modules are damaged.

[0011] The present invention calculates a difference value between the amount of power generated by each of a plurality of strings constituting a solar power generation system when connected to an inverter and when disconnected from the inverter, and then compares the difference value with the amount of power generated under standard test conditions to calculate a string health index, and detects a string in which an abnormality has occurred based on the difference value, thereby enabling the detection of a string in which an abnormality has occurred without a separate device for measuring current and voltage for each string using an MPPT module built into the inverter, thereby improving convenience and efficiency in string management.

[0012] A diagnostic system for measuring string health of a solar power generation system, which includes a plurality of strings including a plurality of solar modules connected in series according to an embodiment of the present invention, and which connects the plurality of strings in parallel and provides generated power by merging direct current power provided from each of the plurality of strings, and which includes an inverter that converts the generated power provided from the junction box into alternating current power and provides it, comprises: a plurality of switching devices connected to output terminals of the strings so as to correspond to each of the plurality of strings and selectively providing the direct current power of the strings to the junction box; and a plurality of switching devices controlling the opening and closing of the plurality of switching devices, sequentially opening each of the plurality of switching devices so that the generated power of the remaining strings except for the string corresponding to the switching device in the open state is provided to the inverter; and in conjunction with the inverter, based on the amount of power generation of all strings measured by the inverter in a state where all switching devices are closed and the amount of power generation measured by the inverter for the remaining strings except for the specific string corresponding to the specific switching device in a state where a specific switching device among the plurality of switching devices is open, the diagnostic system for measuring the health of the string corresponding to the specific switching device The method may include a control device that calculates the actual power generation of a specific string, calculates the actual power generation of each of the plurality of strings, and then detects a string in which an abnormality has occurred based on the calculated actual power generation of the string.

[0013] As an example related to the present invention, the diagnostic system may further include an irradiance measuring unit for measuring irradiance, and the control device may calculate a string health index based on a corrected power generation amount corrected to a power generation amount according to an STC (Standard Test Condition) state using the irradiance measured by the irradiance measuring unit at a time when an opening / closing device corresponding to the string is opened, and the string health index may be calculated based on the power generation amount of the string in the STC state, and when an abnormal string is detected based on the string health index for each string, notification information for the abnormal string is generated and provided.

[0014] As an example related to the present invention, the control device may be characterized in that it detects a specific string in which a string health level is calculated to have a deviation greater than a preset reference value from the string health levels of other multiple strings based on the string health levels of the multiple strings, as the abnormal occurrence string.

[0015] As an example related to the present invention,

[0016] The above control device

[0017]

[0018] The actual power generation of the specific string is calculated according to

[0019] The above P n,measure is the actual power generation of the specific string (n), and P All,measure is the power generation of all strings measured by the inverter based on the state in which all strings are connected to the inverter, and the P -n,measure It may be characterized in that the power generation of the remaining strings is measured by the inverter based on the power generation of the remaining strings excluding the specific string.

[0020] As an example related to the present invention,

[0021] The above control device,

[0022]

[0023] Calculate the string health of the above specific string according to

[0024]

[0025] The above P is the power generation of the specific string under the STC (Standard Test Condition) condition. n,STC , and produces

[0026] The above HL n is the health of the above specific string, and P n,measure is the actual power generation of the specific string, and P n,STC is the power generation amount in the ideal STC state of the specific string, A is the area of ​​the solar module constituting the string, r is the efficiency of the solar module constituting the string, I is the amount of solar radiation, and N is the number of solar modules connected in series constituting the string.

[0027] As an example related to the present invention,

[0028] The above control device measures the solar radiation I measured through the solar radiation measuring unit at the time when the specific opening / closing device is opened. n,measure And the solar radiation I according to the above STC STC Based on

[0029]

[0030] The corrected power generation amount P′ is the power generation amount corrected to the power generation amount when the solar radiation amount according to the STC according to the actual power generation amount of the specific string. n,STC After calculating

[0031]

[0032] According to the string health of the above specific string, HL′ nIt can be characterized by producing .

[0033] As an example related to the present invention, the diagnostic system may be characterized in that it further includes a plurality of protective fuses connected to the output terminal of the switching device, the input terminal of which is connected to the output terminal of the string, to block overcurrent, and each of which is connected to correspond to a plurality of switching devices.

[0034] The present invention, unlike the existing system that is connected to a string and directly measures the DC power of the string, selectively provides the power of the string and sequentially controls a plurality of switching devices individually connected to a plurality of strings, calculates the actual power generation for each string based on the power generation of all strings measured through the inverter and the power generation of the remaining strings excluding the string corresponding to the open switching device, and then calculates the string health index for the power generation performance of the strings and compares them with each other, thereby supporting the accurate detection of strings that have abnormalities due to shading, damage, contamination, etc., and supports the accurate calculation of the power generation for each string without interruption of the inverter's power generation with only a switching circuit that selectively cuts off the DC power of the string rather than a configuration for current-voltage measurement, thereby reducing the complexity of the system and greatly increasing the diagnostic efficiency of the solar power generation system.

[0035] In addition, the present invention provides a maximum voltage (V) by a single MPPT configured in an inverter. mp ) and maximum current (I mp ) can be measured to accurately measure the actual power generation of each string actually used in the power conversion circuit, and through this, not only can the presence or absence of an abnormality in a string be accurately detected with high reliability based on the measurement of the actual power generation of each string, but it also has the effect of supporting rapid action to be taken on a string where an abnormality has occurred.

[0036] In addition, the present invention determines whether there is an abnormality in each string by using the power generation amount measured by each string in the inverter and is configured by connecting a simple open / close circuit to the string, so unlike the current / voltage analysis module of the existing system that is directly connected to the string and measures the current / voltage and thus has a high risk of damage, there is no concern about damage, and thus has the effect of ensuring stable system operation.

[0037] Figure 1 is a configuration diagram of an existing solar power generation monitoring system.

[0038] FIG. 2 is a configuration diagram of a diagnostic system for measuring string health of a solar power generation system according to an embodiment of the present invention.

[0039] FIG. 3 is an operation flowchart of a diagnostic system for measuring string health of a solar power generation system according to an embodiment of the present invention.

[0040] FIG. 4 is an exemplary operation diagram for detecting string abnormalities through actual power generation amount correction of a diagnostic system for string health measurement of a solar power generation system according to an embodiment of the present invention.

[0041] Hereinafter, detailed embodiments of the present invention will be described with reference to the drawings.

[0042] FIG. 2 is a configuration diagram of a diagnostic system (hereinafter, “diagnosis system”) for measuring string health of a solar power generation system according to an embodiment of the present invention.

[0043] As illustrated, the solar power generation system may be configured to include a plurality of strings (10) including a plurality of solar modules (11) that are connected in series with each other, a combiner box (20) that connects the plurality of strings (10) in parallel, combines the direct current power provided from each of the plurality of strings (10) through a protection circuit, and provides generated power to an inverter (30), and an inverter (30) that converts the generated power provided from the combiner box (20) into alternating current power and provides (outputs).

[0044] The diagnostic system according to the present invention for measuring the string health of each of a plurality of strings (10) constituting such a solar power generation system may be configured to include a plurality of switching devices (200) that are connected to correspond to each of the plurality of strings (10) and provide the direct current power of the strings (10) to a connection (20), and a control device (100) that controls (individually controls) the plurality of switching devices (200) that are connected to correspond to each of the plurality of strings (10) and detects whether there is an abnormality in each of the plurality of strings (10) based on the amount of power generation measured for each of the plurality of strings in conjunction with the inverter (30).

[0045] First, the plurality of switching devices (200) are connected to the output terminals of the strings (10) so as to correspond to the plurality of strings (10), and each of the plurality of switching devices (200) has an output terminal connected to the connection box (20) so as to selectively provide the DC power of the string (10) connected thereto to the connection box (20).

[0046] That is, the above-mentioned opening and closing device (200) has an input terminal connected to an output terminal of a string (10) corresponding to itself, and an output terminal connected to the connection box (20), so that the DC power of the string (10) corresponding to itself can be selectively provided to the connection box (20) according to an opening and closing operation.

[0047] At this time, the connection box (20) may be configured to include the plurality of switching devices (200), and may further include a protection circuit breaker (22) that connects the plurality of switching devices (200) in parallel and blocks overcurrent when it occurs.

[0048] In addition, the above-mentioned connection box (20) can generate power by merging the DC power for each string provided from the plurality of switching devices (200) through a protection circuit and provide the generated power to the inverter (30).

[0049] At this time, the output terminal of the protective circuit breaker (22) can be connected to the input terminal of the inverter (30), and the DC power of the plurality of strings can be combined in the protective circuit breaker (22) to generate power and then provide the generated power to the inverter (30).

[0050] In addition, the diagnostic system may include a protection fuse (21) that is connected between the output terminal of the switching device (200) connected to the output terminal of the string (10) and the switching device (200) and the protective circuit breaker (22) to block overcurrent, and may include a plurality of protection fuses (21) that are connected to correspond to each of the plurality of switching devices (200).

[0051] In addition, the inverter (30) can receive the generated power from the connection box (20) and convert the generated power into AC power and output it.

[0052] At this time, the inverter (30) may be configured to include a conversion unit that converts the generated power, which is the combined direct current power, into alternating current power, an MPPT (Maximum Power Point Tracking) unit that tracks the optimal values ​​for each of voltage and current that can obtain the optimal alternating current power through maximum power point tracking and sets them in the conversion unit, and a calculation unit that measures the amount of power generated according to the alternating current power output from the conversion unit and generates measurement information.

[0053] The measurement information provided by the inverter (30) described below can be generated by the operation unit.

[0054] Meanwhile, the control device (100) controls the opening and closing of the plurality of switching devices (200), and sequentially opens each of the plurality of switching devices (200) so that the generated power of the remaining strings (10) (one or more remaining strings (10)) excluding the string (10) corresponding to the switching device (200) (one switching device (200)) in the open state is provided to the inverter (30).

[0055] At this time, the control device (100) controls all of the plurality of switching devices (200) to be closed before sequentially opening the plurality of switching devices (200), or controls all of the plurality of switching devices (200) to be closed before (immediately before) opening each switching device (200), so that the generated power of all of the strings (10) is provided to the inverter (30), and measurement information (or first measurement information) on the amount of power generated of all of the strings (10) measured by the inverter (30) based on the generated power of all of the strings (10) can be received from the inverter (30).

[0056] In addition, the control device (100) may receive measurement information (or second measurement information) on the power generation of the remaining strings (10) (one or more strings (10) corresponding to the remaining strings) measured by the inverter (30) based on the power generation of the remaining strings (10) (one or more strings (10) corresponding to the remaining strings) by opening a specific switching device (200) (one switching device (200)) among the plurality of switching devices (200) excluding the specific switching device (200) from the inverter (30), while sequentially opening the plurality of switching devices (200) one by one (only one at a time), thereby receiving a plurality of measurement information (or second measurement information) corresponding to the plurality of strings (10).

[0057] At this time, the power generation amount of all strings (10) described in the present invention may be a value calculated (obtained) by the inverter (30) (or the calculation unit) measuring the AC power converted by the inverter (30) based on the generated power of all strings (10) provided from the connection box (20), and the power generation amount of the remaining strings (10) may be a value calculated (obtained) by the inverter (30) (or the calculation unit) measuring the AC power converted by the inverter (30) based on the generated power of the remaining strings (10) provided from the connection box (20).

[0058] In addition, the control device (100) opens any one of the plurality of switching devices (200) to separate the first string (10) corresponding to any one of the plurality of strings (10) from the inverter (30), and then, when the reception of measurement information generated by measuring the power generation of the remaining string (10) from the inverter (30) for any one of the switching devices (200) is completed, the control device (100) switches any one of the plurality of switching devices (200) to a closed state to reconnect the first string (10) to the inverter (30), and then opens another one of the plurality of switching devices (200) to separate the second string (10) corresponding to any one of the plurality of strings (10) from the inverter (30), and receives the measurement information generated by measuring the power generation of the remaining string (10) from the inverter (30). By sequentially opening the device (200), a plurality of pieces of measurement information corresponding to each of the plurality of strings (10) can be received. At this time, the measurement information may be information corresponding to a string (10) corresponding to the opening / closing device (200) in an open state.

[0059] In addition, the control device (100) can communicate with the operation unit configured in the inverter (30) through wires or wirelessly, and can receive the first measurement information and the second measurement information from the operation unit.

[0060] At this time, the control device (100) may be configured externally, separately from the inverter (30) and the connection box (20), or may be configured as a component included in either the inverter (30) or the connection box (20).

[0061] In addition, the control device (100) can communicate with various devices including a computing unit through a communication network, and the communication network described in the present invention can include a wired / wireless communication network, and examples of such wireless communication networks include wireless LAN (WLAN), DLNA (Digital Living Network Alliance), Wibro (Wireless Broadband), WiMAX (World Interoperability for Microwave Access: Wimax), GSM (Global System for Mobile communication), CDMA (Code Division Multi Access), CDMA2000 (Code Division Multi Access 2000), EV-DO (Enhanced Voice-Data Optimized or Enhanced Voice-Data Only), WCDMA (Wideband CDMA), HSDPA (High Speed ​​Downlink Packet Access), HSUPA (High Speed ​​Uplink Packet Access), and IEEE 802.16, Long Term Evolution (LTE), Long Term Evolution-Advanced (LTE-A), Wireless Mobile Broadband Service (WMBS), 5G mobile communication service, Bluetooth, LoRa (Long Range), RFID (Radio Frequency Identification), Infrared Data Association (IrDA), UWB (Ultra Wideband), ZigBee, Near Field Communication (NFC), Ultra Sound Communication (USC), Visible Light Communication (VLC), Wi-Fi, Wi-Fi Direct, etc. may be included. In addition, wired communication networks may include wired Local Area Network (LAN), wired Wide Area Network (WAN), Power Line Communication (PLC), USB communication, Ethernet, serial communication, optical / coaxial cables, etc.

[0062] In addition, the control device (100) may be configured to include a communication unit (or interface unit), a storage unit, and a control unit, and is not limited thereto, and may be configured to include more components or may be configured with some components omitted.

[0063] In addition, the control unit executes the overall control function of the control device (100), and the control unit may include RAM, ROM, CPU, GPU, and a bus, and the RAM, ROM, CPU, GPU, etc. may be connected to each other through a bus. At this time, the operation configuration of the control device (100) described in the present invention may be performed by the control unit, and the communication unit may communicate with the operation unit using various widely known wired and wireless communication methods.

[0064] Meanwhile, the control device (100) calculates the power generation of a specific string (10) corresponding to the specific switching device (200) based on measurement information on the power generation of all strings (10) corresponding to the specific switching device (200) in the open state and measurement information on the power generation of the remaining strings (10), and can calculate the power generation of the string (10) for each of the plurality of strings, and can detect a string (10) in which an abnormality has occurred based on this. This will be described in detail with reference to the operation flowchart of the control device (100) illustrated in FIG. 3 based on the above-described configuration.

[0065] First, the control device (100) measures the power generation of all strings (10) in conjunction with the inverter (30) as described above (S1), and then opens a specific switching device (200) among the plurality of switching devices (200) (S2, S3) to measure the power generation of the remaining strings (10) except for the string (10) corresponding to the specific switching device (200) in conjunction with the inverter (30) (S4).

[0066] Thereafter, the actual power generation amount of the specific string (10) can be calculated according to the following mathematical formula 2 (S6).

[0067]

[0068] At this time, the above P n,measure is the actual power generation of the specific string (10) (or string n), and the PAll,measure is the power generation of all strings (10) measured by the inverter (30) based on the state in which all strings (10) are connected to the inverter (30) (or based on the power generation of all strings (10)), and the P -n,measure It may be the power generation amount of the remaining strings (10) measured by the inverter (30) based on the power generation of the remaining strings (10) excluding the specific string (10) (or string n).

[0069] That is, the control device (100) calculates a difference in power generation, which is the difference between the power generation of all strings (10) according to the measurement information (first measurement information) received from the inverter (30) that received the power generation of all strings (10) in a closed state with all switching devices (200) closed, and the power generation of the remaining strings (10) according to the measurement information (second measurement information) received from the inverter (30) that received the power generation of the remaining strings (10) excluding a specific string (10) corresponding to a specific switching device (200) in an open state, and calculates the difference in power generation as the actual power generation of the specific string (10).

[0070] In addition, the control device (100) can calculate the actual power generation of the string (10) for each of the plurality of strings as described above, in the same manner as calculating the actual power generation of the specific string (10) by sequentially changing the opening / closing device (200) that is the target of opening.

[0071] Meanwhile, the control device (100) determines the string health (HL) of the specific string (10) according to the following mathematical expression 3. n ) can be produced.

[0072]

[0073] At this time, the above P n,measure is the actual power generation of the above specific string (10), and the above P n,STCis the power generation amount (or the expected power generation amount of the specific string (10)) in the STC (Standard Test Condition) state (or ideal STC state) of the specific string (10).

[0074] In addition, the control device (100) calculates the power generation amount of the specific string (10) in the STC state, which is the P, according to the following mathematical expression 4. n,STC can be produced.

[0075]

[0076] At this time, the above P is the power generation amount (W) of the specific string (10), and the above A is the area (m) of the solar module (or one or more solar modules) constituting the specific string (10). 2 ) (or total area), wherein r is the efficiency (%) of the solar module (or one or more solar modules) constituting the specific string (10), and I is the irradiance (W / m 2 ), and N is the number of solar modules (or multiple solar modules) connected in series (in series with each other) that constitute the specific string (10).

[0077] In addition, the solar irradiance I in the above STC state is 1000 (W / m 2 ) may be.

[0078] Here, setting information for the amount of power generation in the STC state for each of the plurality of strings can be preset in the control device (100), and the amount of power generation in the STC state for each of the plurality of strings can be preset in the setting information.

[0079] Accordingly, the control device (100) can calculate the string health corresponding to the specific string (10) based on the actual power generation of the specific string (10) and the power generation in the STC state corresponding to the specific string (10) set in the setting information.

[0080] In addition, the above STC (Standard Test Condition) is a condition (state) used as a reference for measuring the power generation of solar modules, with a reference temperature of 25℃ and an irradiance of 1000 (W / m 2 ) can include (mean) the state of.

[0081] That is, the control device (100) can calculate the string health ratio for the power generation performance of the string (10) by comparing the actual power generation of the specific string (10) obtained by opening the opening / closing device (200) with the expected power generation, which is the power generation of the specific string (10) under standard test conditions.

[0082] In addition, the control device (100) can calculate the string health for each of the plurality of strings in the same manner as calculating the string health for the specific string (10) (S9).

[0083] In addition, a plurality of device identification information corresponding to each of the plurality of opening and closing devices (200) may be stored in advance in the storage of the control device (100), and the control device (100) may match the first measurement information, the second measurement information, and the string health level obtained for the string (10) corresponding to the opening and closing device (200) for each of the plurality of opening and closing devices with the device identification information corresponding to the opening and closing device (200) and store them in the storage. At this time, the device identification information may be preset string identification information for distinguishing and identifying the string (10) corresponding to the opening and closing device (200) or may include the corresponding string identification information.

[0084] Accordingly, the control device (100) compares the string health levels of the plurality of strings (10) and the plurality of string health levels corresponding to each of the plurality of strings (S10) based on the string health levels calculated for each of the plurality of strings, and detects a specific string (10) having a string health level that deviates by a preset standard or more from the string health levels of other strings (10) among the plurality of strings (10) as an abnormal string (10) (S11).

[0085] Alternatively, the control device (100) may calculate an average value by averaging the string health of the plurality of strings, and then compare the average value with the string health of the plurality of strings to detect a specific string (10) in which a string health value having a deviation greater than or equal to a preset reference value from the average value occurs (corresponding to a string health value having a deviation greater than or equal to a reference value) as an abnormal string (10).

[0086] Alternatively, the control device (100) may detect a string (10) in which a string health level exceeding a preset range in the control device (100) is calculated as an abnormal string (10) in which an abnormality has occurred.

[0087] In addition, when the above-described abnormal occurrence string (10) is detected, the above-described control device (100) can identify (extract) device identification information corresponding to the abnormal occurrence string (10) from the storage unit and generate notification information (abnormal occurrence information) including the identified (extracted) device identification information (S12).

[0088] At this time, the control device (100) may include a display unit that displays various types of information, and may display the notification information through the display unit.

[0089] Alternatively, the control device (100) can communicate with an external device through the communication unit, either wired or wirelessly, and transmit the notification information to the external device through the communication unit.

[0090] Through this, the present invention can provide a method for identifying a string (10) in which an abnormality has occurred based on the above notification information.

[0091] Meanwhile, in the above-described configuration, the actual power generation (P) of a specific string (10) used when calculating the string health of the specific string (10) n,measure ) is the power generation according to the actual solar radiation at the time of opening the opening / closing device (200) corresponding to the specific string (10), while the power generation (P) in the STC state of the specific string (10) used when calculating the string health of the specific string (10) n,STC ) is the solar irradiance (1000 W / m) according to STC status. 2 ) is the power generation amount, and since the actual solar radiation fluctuates from time to time, in order to increase the reliability of the string health of the specific string (10), the actual power generation amount (P) of the specific string (10) n,measure ) needs to be corrected to the value when the solar radiation condition of STC is used.

[0092] That is, the actual power generation (P) of the specific string (10) n,measure ) is the power generation amount according to the actual solar radiation at the time of opening the opening / closing device (200) corresponding to the specific string (10), and the power generation amount (P) in the STC state of the specific string (10) n,STC ) is the power generation amount in an ideal state according to the STC state, so it is necessary to correct the actual power generation amount of the specific string (10) to the power generation amount when the solar radiation amount is according to the STC state.

[0093] To this end, the diagnostic system according to the present invention may be configured to further include an irradiance measuring unit (300) that measures irradiance, and the irradiance measuring unit (300) may be configured to be communicatively connected to the control device (100) or included in the control device (100).

[0094] Accordingly, the control device (100) controls the irradiance measuring unit (300) to measure irradiance through the irradiance measuring unit (300) when the opening / closing device (200) corresponding to the specific string (10) is opened (at the time of opening) (S5), and can receive irradiance information according to the irradiance measurement from the irradiance measuring unit (300), and can match the irradiance information with device identification information corresponding to the opened opening / closing device (200) and store it in the storage unit.

[0095] In addition, the control device (100) can correct the actual power generation of a specific string (10) to the irradiance condition of the STC state according to the following mathematical expression 5 using the irradiance according to the irradiance information (S6, S7).

[0096]

[0097] That is, the control device (100) measures the solar radiation I measured through the solar radiation measuring unit (300) at the time when the specific opening / closing device (200) corresponding to the specific string (10) is opened. n,measure and I, the amount of solar radiation according to STC (Standard Test Condition) (STC status) STC Based on the above mathematical expression 5, the actual power generation of the specific string (10) is corrected to the power generation amount when the solar radiation is according to the STC, which is the corrected power generation amount P′ n,STC can be produced.

[0098] At this time, the above I STC is 1000(W / m 2 ) may be.

[0099] In addition, the control device (100) is P in the above mathematical expression 3. n,measure Instead, the above P′ n,STC HL′, which is the string health of a specific string (10) to which the above-mentioned corrected power generation amount is reflected, according to the following mathematical expression 6 applied n can be produced (S8).

[0100]

[0101] In addition, the control device (100) can calculate the string health reflecting the corrected power generation amount for each of the plurality of strings in the same manner as the method of calculating the string health reflecting the corrected power generation amount for the specific string (10) (S9).

[0102] Accordingly, as illustrated in FIG. 4, the control device (100) can calculate a string health level reflecting the corrected power generation amount of the string (10) in the STC state (STC condition), and can support the detection of a string (10) in which an abnormality has occurred by clearly distinguishing it based on the string health levels of multiple strings.

[0103] At this time, the control device (100) calculates the string health (HL) calculated through the mathematical expression 3. n ) instead of the string health (HL′) calculated through the above mathematical formula 6. n ) can be used to detect abnormal occurrence strings as described above (S10, S11).

[0104] As described above, if the irradiance correction is not performed in the control device (100), the cause of the decrease in the power generation of the string cannot be clearly distinguished, so the control device (100) corrects the actual power generation of the string to the power generation when the irradiance is according to the STC (Standard Test Condition) state based on the actual power generation of the string and the irradiance measured when measuring the power generation for each of the plurality of strings, and then calculates the string health level with the irradiance correction reflected based on this.

[0105] In addition, the control device (100) can generate and provide notification information about an abnormality occurrence string when an abnormality occurrence string is detected according to the preset abnormality occurrence judgment conditions described above (S12).

[0106] As described above, unlike the existing system that is connected to a string and directly measures the DC power of the string, the present invention selectively provides the power of the string and sequentially controls a plurality of switching devices individually connected to a plurality of strings, calculates the actual power generation for each string based on the power generation of all strings measured through the inverter and the power generation of the remaining strings excluding the string corresponding to the open switching device, and then calculates the string health index for the power generation performance of the strings and compares them with each other, thereby supporting the accurate detection of strings that have abnormalities due to shading, damage, contamination, etc., and supports the accurate calculation of the power generation for each string without interruption of the inverter's power generation with only a switching circuit that selectively cuts off the DC power of the string rather than a configuration for current-voltage measurement, thereby reducing the complexity of the system and greatly increasing the diagnostic efficiency of the solar power generation system.

[0107] In addition, the present invention provides a maximum voltage (V) by a single MPPT configured in an inverter. mp ) and maximum current (I mp ) can be measured to accurately measure the actual power generation of each string actually used in the power conversion circuit, and through this, not only can it accurately detect whether a string is abnormal with high reliability based on the measurement of the actual power generation of each string, but it can also support rapid action to be taken on a string where an abnormality has occurred.

[0108] In addition, the present invention determines whether there is an abnormality in each string by using the power generation amount measured by each string in the inverter and is configured by connecting a simple open / close circuit to the string, so unlike the current / voltage analysis module of the existing system that is directly connected to the string and measures the current / voltage and thus has a high risk of damage, there is no concern about damage, and thus stable system operation can be guaranteed.

[0109]

[0110] The components described in the embodiments of the present invention may be implemented using one or more general-purpose computers or special-purpose computers, such as, for example, a storage unit such as a memory, a processor, a controller, an arithmetic logic unit (ALU), a digital signal processor, a microcomputer, a field programmable gate array (FPGA), a programmable logic unit (PLU), hardware such as a microprocessor, software including an instruction set, or a combination thereof, or any other device capable of executing and responding to instructions.

[0111] Those skilled in the art will appreciate that modifications and variations of the above-described content may be made without departing from the essential characteristics of the present invention. Therefore, the embodiments disclosed herein are intended to illustrate, rather than limit, the technical spirit of the present invention, and the scope of the technical spirit of the present invention is not limited by these embodiments. The scope of protection of the present invention should be construed according to the following claims, and all technical ideas within the scope equivalent thereto should be construed as being included within the scope of the present invention.

[0112] Description of the symbol

[0113] 10: String 11: Solar module

[0114] 20: Connection box 30: Inverter

[0115] 21: Protective fuse 22: Protective circuit breaker

[0116] 100: Control device 200: Switching device

[0117] 300: Solar radiation measurement unit

Claims

1. A diagnostic system for measuring the health of strings of a solar power generation system, comprising a plurality of strings including a plurality of solar modules connected in series with each other, a junction box that connects the plurality of strings in parallel and provides generated power by merging the direct current power provided from each of the plurality of strings, and an inverter that converts the generated power provided from the junction box into alternating current power and provides it, A plurality of switching devices connected to the output terminals of the strings to correspond to each of the plurality of strings and selectively provide the DC power of the strings to the connection box; and A diagnostic system for measuring string health of a solar power generation system, comprising a control device that controls the opening and closing of the plurality of switching devices, sequentially opens each of the plurality of switching devices, and provides the generated power of the remaining strings except for the string corresponding to the switching device in the open state to the inverter, and calculates the actual generated power of a specific string corresponding to the specific switching device based on the generated power of all strings measured by the inverter in a state where all switching devices are closed and the generated power measured by the inverter for the remaining strings except for the specific string corresponding to the specific switching device in a state where a specific switching device among the plurality of switching devices is open, and then calculates the actual generated power of each of the plurality of strings and detects a string in which an abnormality has occurred based thereon.

2. In claim 1, It further includes a solar radiation measuring unit for measuring solar radiation, A diagnostic system for measuring string health of a solar power generation system, characterized in that the control device calculates a string health index based on a corrected power generation amount corrected to a power generation amount according to an STC (Standard Test Condition) state using the irradiance measured by the irradiance measuring unit at the time when the switch corresponding to the string is opened, and the power generation amount of the string in the STC state, and when an abnormal string is detected based on the string health index of each string, notification information for the abnormal string is generated and provided.

3. In claim 2, A diagnostic system for measuring string health of a solar power generation system, characterized in that the control device detects a specific string in which a string health level is calculated to have a deviation greater than a preset standard from the string health levels of other multiple strings based on the string health levels of the multiple strings, as the abnormal string.

4. In claim 2, The above control device The actual power generation of the specific string is calculated according to The above P n,measure is the actual power generation of the specific string (n), and P All,measure is the power generation of all strings measured by the inverter based on the state in which all strings are connected to the inverter, and the P -n,measure A diagnostic system for measuring string health of a solar power generation system, characterized in that the power generation amount of the remaining strings measured by the inverter is based on the power generation of the remaining strings excluding the specific string.

5. In claim 4, The above control device, Calculate the string health of the specific string according to The above P is the power generation of the specific string under the STC (Standard Test Condition) condition. n,STC , and produces The above HL n is the health of the above specific string, and P n,measure is the actual power generation of the specific string, and P n,STC A diagnostic system for measuring string health of a solar power generation system, characterized in that: is the power generation amount in the ideal STC state of the specific string, A is the area of ​​the solar modules constituting the string, r is the efficiency of the solar modules constituting the string, I is the amount of solar radiation, and N is the number of solar modules connected in series constituting the string.

6. In claim 5, The above control device measures the solar radiation I measured through the solar radiation measuring unit at the time when the specific opening / closing device is opened. n,measure And the solar radiation I according to the above STC STC Based on The corrected power generation amount P′ is the power generation amount corrected to the power generation amount when the solar radiation amount according to the STC according to the actual power generation amount of the specific string. n,STC After calculating According to the string health of the above specific string, HL′ n A diagnostic system for measuring string health of a solar power generation system, characterized by producing .

7. In claim 1, A diagnostic system for measuring the health of a string of a solar power generation system, characterized in that the input terminal is connected to the output terminal of the switching device connected to the output terminal of the string to block overcurrent and further includes a plurality of protection fuses connected to correspond to each of the plurality of switching devices.

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