Ground fault determination system and ground fault determination program

Abstract

To determine the presence / absence of a ground fault in a solar power generation system with a simple structure.SOLUTION: A ground fault determination system includes a measurement device and an information terminal that communicates with the measurement device. The measurement device includes a measurement value transmission unit that acquires, as measurement values, an open-circuit voltage of a solar battery string formed by serial connection of solar battery modules, a positive-electrode-to-ground voltage of the solar battery string, and a negative-electrode-to-ground voltage of the solar battery string, and transmits the measurement values to the information terminal. The information terminal includes a ground fault determination unit that determines the presence or absence of a ground fault in the solar battery string using the measurement values received from the measurement device.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present invention relates to a ground fault determination system and a ground fault determination program.

Background Art

[0002] Conventionally, in a photovoltaic power generation system, a technique for determining the presence or absence of a ground fault is known. As an example, for instance, a voltage measuring instrument measures the voltage of a solar cell array configured by connecting a plurality of solar cell modules in series, and the voltage between the output terminal on the positive electrode side or the negative electrode side and the ground, and a technique for determining the presence or absence of a ground fault from the two voltage values is known.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the conventional technique described above, a voltage measuring instrument having a function of identifying a grounded solar cell module is used. For this reason, in the conventional technique, a general-purpose voltage measuring instrument cannot be used, and it has been difficult to determine the presence or absence of a ground fault with a simple configuration.

[0005] An object of the present disclosure is to determine the presence or absence of a ground fault in a photovoltaic power generation system with a simple configuration.

Means for Solving the Problems

[0006] The disclosed technology is a ground fault determination system including a measurement device and an information terminal that communicates with the measurement device. The measurement device has a measurement value transmission unit that acquires, as measurement values, the open-circuit voltage of a solar cell string configured by connecting solar cell modules in series, the voltage between the positive electrode of the solar cell string and the ground, and the voltage between the negative electrode of the solar cell string and the ground, and transmits them to the information terminal. The information terminal is a ground fault determination system having a ground fault presence / absence determination unit that determines the presence or absence of a ground fault in the solar cell string using the measurement values received from the measurement device.

Advantages of the Invention

[0007] It is possible to determine the presence or absence of a ground fault in a photovoltaic power generation system with a simple configuration.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Mode for Carrying Out the Invention

[0009] (First Embodiment) Hereinafter, with reference to the drawings, the first embodiment will be described. FIG. 1 is a diagram showing an example of the system configuration of the grounding determination system according to the first embodiment.

[0010] As shown in FIG. 1, the grounding determination system 100 according to the first embodiment includes an information terminal 200 and a measurement device 300. In the grounding determination system 100, the information terminal 200 and the measurement device 300 are connected by wireless communication. Note that the information terminal 200 and the measurement device 300 may be connected by wired communication.

[0011] The measurement device 300 is an example of a voltage measuring device that measures the voltage of the solar cell string 400. The measurement device 300 measures the open-circuit voltage of the solar cell string 400 to be measured, the voltage between the positive electrode of the solar cell string 400 and the ground, and the voltage between the negative electrode of the solar cell string 400 and the ground, and transmits these three voltages as measurement values to the information terminal 200.

[0012] The solar cell string 400 is a constituent unit of the solar cell array, and a plurality of solar cell strings constitute one solar cell array included in one solar power generation device. In the following description, the solar cell string 400 may be simply referred to as the string 400. Details of the string 400 will be described later.

[0013] When the information terminal 200 receives the measurement value from the measurement device 300, it determines the presence or absence of grounding in the string 400 using the received measurement value. In other words, the information terminal 200 detects the grounding in the solar power generation system including the string 400.

[0014] Hereinafter, with reference to FIG. 2, the string 400 will be described. FIG. 2 is a diagram for explaining the string according to the first embodiment.

[0015] As shown in FIG. 2, the string 400 includes solar cell modules 401 to 408 connected in series, a positive electrode side terminal P, and a negative electrode side terminal N. Each of the solar cell modules 401 to 408 is composed of a plurality of solar cells (solar battery cells). In the following description of the first embodiment, the solar cell module may be simply referred to as a module. In the example of FIG. 2, the number of modules included in the string 400 is eight, but the number of modules included in the string 400 is not limited to eight and may be any number.

[0016] In the following description of the first embodiment, the voltage between the positive electrode side terminal P and the negative electrode side terminal N is defined as the open circuit voltage V of the string 400 PN . Also, in the following description, the voltage between the positive electrode side terminal P and the ground is defined as the positive electrode to ground voltage V PE , and the voltage between the negative electrode side terminal N and the ground is defined as the negative electrode to ground voltage V NE .

[0017] Next, referring to FIG. 3, the hardware configuration of the information terminal 200 according to the first embodiment will be described. FIG. 3 is a diagram showing an example of the hardware configuration of the information terminal according to the first embodiment.

[0018] The information terminal 200 according to the first embodiment is a computer including an input device 21, an output device 22, a drive device 23, an auxiliary storage device 24, a memory device 25, an arithmetic processing device 26, and an interface device 27, which are mutually connected by a bus B. More specifically, the information terminal 200 may be a portable computer or a smartphone or the like.

[0019] The input device 21 is a device for inputting various types of information and is realized by, for example, a touch panel or the like. The output device 22 is for outputting various types of information and is realized by, for example, a display (display device) or the like. The interface device 27 includes a LAN card or the like and is used to connect to a network.

[0020] The ground fault determination program that realizes the ground fault determination function of the information terminal 200 is at least a part of various programs that control the information terminal 200. The ground fault determination program is provided, for example, by distribution of the recording medium 28 or download from a network. The recording medium 28 on which the ground fault determination program is recorded can use various types of recording media, such as a recording medium that optically, electrically, or magnetically records information, like a CD-ROM, a flexible disk, a magneto-optical disk, etc., or a semiconductor memory that electrically records information, like a ROM, a flash memory, etc.

[0021] When the recording medium 28 on which the ground fault determination program is recorded is set in the drive device 23, the ground fault determination program recorded on the recording medium 28 is installed from the recording medium 28 via the drive device 23 into the auxiliary storage device 24. The ground fault determination program downloaded from the network is installed into the auxiliary storage device 24 via the interface device 27.

[0022] The auxiliary storage device 24 of the information terminal 200 stores the ground fault determination program installed in the information terminal 200, and also stores various necessary files, data, etc. of the information terminal 200. The memory device 25 reads out the ground fault determination program from the auxiliary storage device 24 and stores it when the information terminal 200 is started. Then, the arithmetic processing device 26 realizes various processes as described later according to the ground fault determination program stored in the memory device 25.

[0023] Next, with reference to FIG. 4, the functional configurations of the measurement device 300 and the information terminal 200 will be described. FIG. 4 is a diagram for explaining the functional configuration of the information terminal according to the first embodiment.

[0024] As shown in FIG. 4, the measurement device 300 has a measurement value transmission unit 310. The measurement value transmission unit 310 measures the open-circuit voltage V of the solar cell string 400, the voltage V between the positive electrode of the solar cell string 400 and the ground, and the voltage V between the negative electrode of the solar cell string 400 and the ground. PN of the solar cell string 400, and the voltage V between the positive electrode of the solar cell string 400 and the ground, and the voltage V between the negative electrode of the solar cell string 400 and the ground. PE of the solar cell string 400, and the voltage V between the negative electrode of the solar cell string 400 and the ground. NEMeasure [something] and [something else], and transmit the measurement value, which is the measurement result, to the information terminal 200.

[0025] Note that the measurement value transmission unit 310 and the measurement device 300 may have an arithmetic processing unit including a storage device and may be functions realized by the arithmetic processing unit.

[0026] As shown in FIG. 4, the information terminal 200 has a ground fault determination unit 230. The ground fault determination unit 230 uses the open circuit voltage V of the string 400 measured by the measurement device 300, the voltage V between the positive electrode and the ground, and the voltage V between the negative electrode and the ground to determine the presence or absence of a ground fault in the string 400. PN , the voltage V between the positive electrode and the ground PE , the voltage V between the negative electrode and the ground NE to determine the presence or absence of a ground fault in the string 400.

[0027] The ground fault determination unit 230 of the first embodiment may be realized, for example, by installing an application distributed to the information terminal 200 in advance on the information terminal 200.

[0028] The ground fault determination unit 230 includes a communication control unit 231, a measurement value acquisition unit 232, a measurement target determination unit 233, a ground fault presence / absence determination unit 234, a parameter determination unit 235, a ratio calculation unit 236, a number calculation unit 237, a display control unit 238, and an information storage unit 239.

[0029] The communication control unit 231 controls the communication between the information terminal 200 and the measurement device 300. More specifically, the communication control unit 231 connects the information terminal 200 to the measurement device 300 so that the measurement value can be received from the measurement device 300.

[0030] The measurement value acquisition unit 232 acquires the open circuit voltage V of the string 400, which is the measurement value, the voltage V between the positive electrode and the ground, and the voltage V between the negative electrode and the ground from the measurement device 300 connected by the communication control unit 231. PN , the voltage V between the positive electrode and the ground PE , the voltage V between the negative electrode and the ground NE from the measurement device 300 connected by the communication control unit 231.

[0031] The measurement target determination unit 233 determines whether the measurement value acquired by the measurement value acquisition unit 232 is used for determining the presence or absence of a ground fault. In other words, the measurement target determination unit 233 determines whether to exclude the measurement value acquired by the measurement value acquisition unit 232 from the measurement values used for determining the presence or absence of a ground fault by the ground fault presence / absence determination unit 234.

[0032] Specifically, when the measurement value acquired by the measurement value acquisition unit 232 satisfies the following exclusion target conditions, the measurement target determination unit 233 excludes the acquired measurement value from the values used for determining the presence or absence of a ground fault. Details of the exclusion target conditions will be described later.

[0033] Note that the case where the measurement value satisfies the exclusion target conditions is, for example, the case where the measurement value acquired by the measurement value acquisition unit 232 is an incorrect input.

[0034] The ground fault presence / absence determination unit 234 uses the measurement value acquired by the measurement value acquisition unit 232 to determine the presence or absence of a ground fault in the string 400. Specifically, the ground fault presence / absence determination unit 234 determines the presence or absence of a ground fault in the string 400 according to the combination of Condition 1, Condition 2, and Condition 3. Details of Condition 1, Condition 2, and Condition 3 will be described later.

[0035] The parameter determination unit 235 determines whether a parameter related to the module included in the string 400 has been input to the information terminal 200. In addition, the parameter determination unit 235 determines the type of the parameter input to the information terminal 200. The parameters related to the module include the number of modules included in the string 400, the specification of the open-circuit voltage of the modules included in the string 400, and the number of years elapsed of the solar cell modules included in the string 400.

[0036] The ratio calculation unit 236 calculates the ratio of the number of modules from the positive terminal P or the negative terminal N to the location where a ground fault has occurred to the total number of modules included in the string 400.

[0037] The number calculation unit 237 calculates the number of modules from the positive electrode side terminal P or the negative electrode side terminal N to the location where the ground fault has occurred, using the input parameters.

[0038] In the following description, the ratio calculated by the ratio calculation unit 236 and the number calculated by the number calculation unit 237 may be expressed as information indicating the location where the ground fault has occurred.

[0039] The display control unit 238 causes the display of the information terminal 200 to display the determination result by the ground fault presence / absence determination unit 234, the calculation results by the number calculation unit 237 and the ratio calculation unit 236, and the like.

[0040] The information storage unit 239 stores, as measurement information, the information displayed on the display of the information terminal 200 by the display control unit 238 and the measurement values acquired by the measurement value acquisition unit 232, in an auxiliary storage device 24 or the like, in association with each other.

[0041] That is, the measurement information includes the open circuit voltage V of the string 400 acquired by the measurement value acquisition unit 232 PN , the voltage V between the positive electrode and the ground PE , and the voltage V between the negative electrode and the ground. NE The measurement information also includes the determination result by the ground fault presence / absence determination unit 234, the ratio calculated by the ratio calculation unit 236, and the number calculated by the number calculation unit 237. The measurement information further includes information identifying the measurement device 300 connected to the information terminal 200, and information indicating the terminal (positive electrode side terminal P or negative electrode side terminal N) that was used as the starting point when calculating the ratio by the ratio calculation unit 236 and the number by the number calculation unit 237.

[0042] Further, the measurement information may include information indicating the date and time when the measurement value was obtained. Also, the measurement information may include image data captured by the information terminal 200. The image data may be still image data or moving image data. The image data captured by the information terminal 200 may be, for example, image data obtained by photographing the string 400 to be measured. Note that the image data included in the measurement information may be image data captured by an imaging device other than the information terminal 200. The imaging device other than the information terminal 200 may be, for example, image data captured by a fixed-point camera installed near the solar cell array including the string 400.

[0043] Next, with reference to FIG. 5, the processing of the information terminal 200 will be described. FIG. 5 is a flowchart for explaining the processing of the information terminal according to the first embodiment.

[0044] As shown in FIG. 5, the ground fault determination unit 230 of the information terminal 200 connects to the measurement device 300 through the communication control unit 231 to enable communication (step S501).

[0045] Subsequently, when the measurement is started in the measurement device 300 and the measurement value is transmitted from the measurement value transmission unit 310, the ground fault determination unit 230 acquires the measurement value transmitted from the measurement device 300 through the measurement value acquisition unit 232 (step S502).

[0046] Subsequently, the ground fault determination unit 230 determines, through the measurement target determination unit 233, whether to use the measurement value acquired in step S502 for determining the presence or absence of a ground fault (step S503). In other words, the ground fault determination unit 230 determines, through the measurement target determination unit 233, whether the measurement value acquired in step S502 satisfies the following exclusion target conditions. · Exclusion target conditions |V PE |+|V NE |>|V PN | In step S503, if the measurement value obtained in step S502 satisfies the exclusion target condition, the ground fault determination unit 230 excludes this measurement value from the measurement values used for determining the presence or absence of a ground fault described later (step S504), and returns to step S502.

[0047] In step S503, if it is determined that the measurement value obtained in step S502 does not satisfy the exclusion target condition, the ground fault determination unit 230 determines the presence or absence of a ground fault in the string 400 to be measured by the ground fault presence / absence determination unit 234 (step S505).

[0048] The processing of the ground fault presence / absence determination unit 234 will be described below. The ground fault presence / absence determination unit 234 may determine the presence or absence of a ground fault according to any one of the following conditions 1, 2, and 3. ·Condition 1 The voltage V between the positive electrode and the ground after a certain time from the start of measurement PE is the voltage V between the positive electrode and the ground PE ± a certain value The voltage V between the negative electrode and the ground after a certain time from the start of measurement NE is the voltage V between the negative electrode and the ground NE ± a certain value ·Condition 2 |V PN |-|V PE |-|V NE |≦α α: First predetermined value ·Condition 3 (|V PN |-|V PE |-|V NE |) / |V PN |≦β β: Second predetermined value The ground fault presence / absence determination unit 234 may determine that there is a ground fault, for example, when the measurement value obtained in step S502 satisfies either one of condition 2 or condition 3.

[0049] Also, after the measurement by the measuring device 300 is started, the ground fault presence / absence determination unit 234 repeats the processing from step S502 to step S504 at a predetermined interval for a certain time, and when the measurement value obtained in step S502 satisfies condition 1 after a certain time, it may determine that there is a ground fault.

[0050] Furthermore, the ground fault presence / absence determining unit 234 may determine the presence / absence of a ground fault according to a combination of the conditions 1, 2, and 3.

[0051] For example, the ground fault presence / absence determining unit 234 may determine the presence or absence of a ground fault by combining Condition 2 and Condition 3. In this case, the ground fault presence / absence determining unit 234 may determine that a ground fault exists when the measurement value acquired in step S502 satisfies both Conditions 2 and 3.

[0052] Furthermore, the ground fault presence / absence determining unit 234 may determine the presence or absence of a ground fault according to a combination of Condition 1 and Condition 2. In this case, the ground fault presence / absence determining unit 234 may determine that a ground fault exists if the measurement value acquired within a certain time period after the start of measurement satisfies Condition 2, and the measurement value acquired after the certain time period after the start of measurement satisfies Condition 1.

[0053] Furthermore, the ground fault presence / absence determining unit 234 may determine the presence or absence of a ground fault according to a combination of Condition 1 and Condition 3. In this case, the ground fault presence / absence determining unit 234 may determine that a ground fault exists if the measurement value acquired within a certain time period after the start of measurement satisfies Condition 3, and the measurement value acquired after the certain time period after the start of measurement satisfies Condition 1.

[0054] In the first embodiment, the conditions or combinations of conditions that are referred to when the ground fault presence / absence determination unit 234 determines whether or not a ground fault exists may be set in advance by an administrator of the ground fault determination system 100, a user of the information terminal 200, or the like.

[0055] If it is determined in step S505 that a ground fault has occurred, the parameter determination unit 235 of the ground fault determination unit 230 determines whether or not parameters relating to the module have been input to the information terminal 200 (step S506).

[0056] Specifically, the parameter determination unit 235 determines whether at least one of the open-circuit voltage of the modules included in the string 400 and the number of modules included in the string 400 is input.

[0057] In step S506, when no parameter is input, the ground fault determination unit 230 calculates, by the ratio calculation unit 236, the ratio of the number of modules from the positive electrode side terminal P or the negative electrode side terminal N to the location where the ground fault has occurred to the total number of modules included in the string 400. (Step S507).

[0058] The processing of the ratio calculation unit 236 will be described below. The ratio calculation unit 236 calculates the ratio X of the number of modules from the positive electrode side terminal P to the location where the ground fault has occurred according to the following formula (1). P to calculate.

[0059] X P =|V PE | / (|V PE |+|V NE |) Formula (1) Also, the ratio calculation unit 236 calculates the ratio X of the number of modules from the negative electrode side terminal N to the location where the ground fault has occurred according to the following formula (2). N to calculate.

[0060] X N =|V NE | / (|V PE |+|V NE |) Formula (2) In the first embodiment, whether the starting point for calculating the ratio is the positive electrode side terminal P or the negative electrode side terminal N may be set by the user of the information terminal 200.

[0061] In step S506, when a parameter is input, the ground fault determination unit 230 calculates, by the number calculation unit 237, the number of modules from the positive electrode side terminal P or the negative electrode side terminal N to the location where the ground fault has occurred (step S508).

[0062] The processing of the number calculation unit 237 will be described below. When the number Na of modules included in the string 400 is input as a parameter, the number calculation unit 237 calculates the number Np of modules from the positive electrode side terminal P or the negative electrode side terminal N to the location where the ground fault occurs according to the following formula (3).

[0063] Np = Na × X P Or Np = Na × X N Formula (3) In addition, when the open-circuit voltage V of the modules included in the string 400 is input as a parameter, the number calculation unit 237 calculates the number Np of modules from the positive electrode side terminal P or the negative electrode side terminal N to the location where the ground fault occurs according to the following formula (4). oc

[0064] Np = X P × (|V PN |) / |V oc | Or, Np = X N × (|V PN |) / |V oc | Formula (4) Note that (|V PN |) / |V oc | is an approximate formula for the number Na of modules included in the string 400. Also, X P , X N in formula (4) uses the same ones as in formula (1) and formula (2).

[0065] In addition, when the open-circuit voltage V of the modules included in the string 400 and the number of years since the modules were put into use are input as parameters, the number calculation unit 237 calculates the number Np of modules from the positive electrode side terminal P or the negative electrode side terminal N to the location where the ground fault occurs according to the following formula (5). oc

[0066] Np = X P × {(|V PN |) / (|V oc | × γ)} Or, Np = X N × {(|V PN |) / (|V​​oc |×γ)} Equation (5) Note that γ in Equation (5) is a coefficient indicating the degree of deterioration of the module, and it may be a value pre-held in the information terminal 200. Further, γ in Equation (5) may include a parameter that varies with the weather when the measurement by the measuring device 300 is performed.

[0067] Subsequently, the ground fault determination unit 230 causes the display control unit 238 to display the result of the process by the ground fault determination unit 230 on the display (display device) of the information terminal 200 (step S509). Subsequently, the ground fault determination unit 230 causes the information storage unit 239 to store the measurement information in the storage device (step S510), and ends the process.

[0068] Next, with reference to FIGS. 6 to 10, the processing and display example of the information terminal 200 will be described. FIG. 6 is a first diagram showing a display example of the information terminal according to the first embodiment.

[0069] The screen 60A shown in FIG. 6 is an example of the screen displayed on the information terminal 200 in step S501 of FIG. 5. In other words, the screen 60A shown in FIG. 6 is an example of the screen showing the state where the information terminal 200 and the measuring device 300 are connected.

[0070] The screen 60A includes display areas 61 to 64 and operation buttons 65 to 68. The display area 61 is a display area for displaying the measurement value acquired by the information terminal 200 from the measuring device 300. The display area 62 has an input field 62a for parameters displayed. The input field 62a is an input field for inputting the number of modules included in the string 400.

[0071] The display area 63 is a display area for the processing result of the ground fault determination unit 230. The display area 63 includes display areas 63a, 63b, and an operation button 63c.

[0072] The display area 63a is a display area for displaying the determination result of the presence or absence of a ground fault. The display area 63b is a display area for displaying the ratio calculated by the ratio calculation unit 236. In other words, in the display area 63b, the ratio of the number of modules from the positive electrode side terminal P or the negative electrode side terminal N to the location where the ground fault occurred to the total number of modules included in the string 400 is displayed.

[0073] The operation button 63c is an operation button for selecting the positive electrode side terminal P or the negative electrode side terminal N. The ratio calculation unit 236 calculates the ratio to be displayed in the display area 63b starting from the positive electrode side terminal P or the negative electrode side terminal N selected by the operation button 63c.

[0074] The display area 64 displays information indicating the measuring device 300 connected to the information terminal 200.

[0075] The operation button 65 is an operation button for saving an image of the screen displayed on the display of the information terminal 200. When the operation button 65 is operated, the information terminal 200 acquires image data indicating the screen displayed on the display of the information terminal 200, which may be measurement information.

[0076] Further, the information terminal 200 may transmit the measurement information including the image data acquired in response to the operation of the operation button 65 to an external device. In other words, the information terminal 200 may transmit the measurement information including the image data of the screen acquired in response to the operation of the operation button 65, numerical data such as measurement values, and image data obtained by photographing the string 400 to be measured to an external device.

[0077] The operation button 67 is an operation button selected when the parameter to be input is the number of modules included in the string 400. The operation button 68 is an operation button selected when the parameter to be input is the open circuit voltage V of the modules included in the string 400. oc It is an operation button selected in this case.

[0078] In the example of FIG. 6, the operation button 67 is selected, and in the display area 62, an input field 62a for inputting the number of modules included in the string 400 is displayed.

[0079] When the operation button 66 is operated on the screen 60A, the information terminal 200 may start acquiring the measurement values from the measuring device 300. Note that the operation of the information terminal 200 corresponding to the operation of the operation button 66 is not limited to this. For example, when the operation button 66 is operated, the information terminal 200 may display the measurement values acquired by the measurement value acquisition unit 232 in the display area 61.

[0080] FIG. 7 is a second diagram showing a display example of the information terminal according to the first embodiment. The screen 60B shown in FIG. 7 is an example of a screen displayed on the information terminal 200 when the operation button 66 is operated on the screen 60A shown in FIG. 6.

[0081] As shown in FIG. 7, on the screen 60B, in the display area 61, the open circuit voltage V of the string 400, which is the measurement value, PN , the voltage V between the positive electrode and the ground PE , and the voltage V between the negative electrode and the ground NE are displayed. Also, as shown in FIG. 7, the determination result of the presence or absence of a ground fault is displayed in a display area 63a included in the display area 63 of the screen 60B. Further, as shown in FIG. 7, on the screen 60B, at the operation button 63c, the positive electrode side terminal P is selected, and in the display area 63b, the ratio of the number of modules from the positive electrode side terminal P to the location where a ground fault has occurred to the total number of modules included in the string 400 is displayed.

[0082] Also, on the screen 60B shown in FIG. 7, instead of the operation button 66, an operation button 66A may be displayed. The operation button 66A is an operation button for manually inputting the measurement values displayed in the display area 61 and the parameters for the input field 62a.

[0083] When the number of modules included in the string 400 is input to the input field 62a in the screen 60B shown in FIG. 7, the screen transitions to a screen 60C described later.

[0084] Also, when the operation button 65 is operated on the screen 60B shown in FIG. 7, the information terminal 200 stores the image data showing the image of the screen 60B as measurement information. By doing so, the information terminal 200 can store measurement information including the measured value, the determination result of the presence or absence of a ground fault, the ratio of the number of modules to the location where the ground fault occurred, the terminal that is the starting point when counting the number of modules to the location where the ground fault occurred, the number of modules included in the string 400, and the like.

[0085] FIG. 8 is a third diagram showing a display example of the information terminal according to the first embodiment. The screen 60C shown in FIG. 8 is an example of a screen displayed on the information terminal 200 when the number of modules included in the string 400 is input to the input field 62a in the screen 60B shown in FIG. 7.

[0086] As shown in FIG. 8, in the display area 63b of the screen 60C, the specific number of modules from the positive electrode side terminal P to the location where the ground fault occurred, calculated using the number input to the input field 62a, is displayed.

[0087] When the operation button 65 is operated on the screen 60C shown in FIG. 8, the information terminal 200 stores the image data showing the image of the screen 60C as measurement information. By doing so, the information terminal 200 can store measurement information including the measured value, the determination result of the presence or absence of a ground fault, the number of modules to the location where the ground fault occurred, the terminal that is the starting point when counting the number of modules to the location where the ground fault occurred, the number of modules included in the string 400, and the like.

[0088] Next, with reference to FIGS. 9 and 10, the case where the parameter to be input is the open circuit voltage V of the module included in the string 400 oc will be described.

[0089] FIG. 9 is a fourth diagram showing a display example of the information terminal according to the first embodiment. On the screen 60D shown in FIG. 9, the operation button 68 is selected, and instead of the display area 62, the display area 62A is displayed.

[0090] The display area 62A includes input fields 62b and 62c. The input field 62b is an input field for inputting the open-circuit voltage V of the module included in the string 400. oc The input field 62c is an input field for inputting the number of years elapsed of the module included in the string 400.

[0091] When the open-circuit voltage V of the module included in the string 400 is input to the input field 62b in the screen 60D shown in FIG. 9, the screen transitions to the screen 60E described later. oc

[0092] FIG. 10 is a fifth diagram showing a display example of the information terminal according to the first embodiment. The screen 60E shown in FIG. 10 is an example of a screen displayed on the information terminal 200 when the open-circuit voltage V of the module included in the string 400 is input to the input field 62b in the screen 60D shown in FIG. 9. oc

[0093] As shown in FIG. 10, in the display area 63b of the screen 60E, the specific number of modules from the positive terminal P to the location where the ground fault occurred calculated using the open-circuit voltage V input to the input field 62b is displayed. oc

[0094] In addition, in the screen 60E shown in FIG. 10, when the number of years elapsed is input to the input field 62c, the specific number of modules displayed in the display area 63b is the number of modules considering the deterioration of the modules due to the number of years elapsed.

[0095] ​​​In this way, in the first embodiment, the information terminal 200 acquires measurement values from the measuring device 300 and determines the presence or absence of a ground fault in the string 400. Therefore, according to the first embodiment, the determination result does not depend on the function of the measuring device 300. Further, according to the first embodiment, the measuring device 300 only needs to have a function of measuring a DC voltage, and a lightweight portable measuring device can also be used. Therefore, according to the first embodiment, it is possible to determine the presence or absence of a ground fault in the string 400 with a simple configuration using a general-purpose measuring device 300. Furthermore, according to the first embodiment, since it is possible to determine the location where a ground fault has occurred only by voltage measurement, fewer measurement items are required.

[0096] Also, in the first embodiment, since it is only voltage measurement, it is possible to determine the location where a ground fault has occurred without applying a voltage to a module that may be faulty.

[0097] Furthermore, in the first embodiment, when parameters related to the module are input, the number of modules up to the location where a ground fault has occurred in the string 400 can be specifically specified using the parameters.

[0098] Furthermore, in the first embodiment, as parameters, the number of modules included in the string 400 and the open-circuit voltage of the module may be input. In this way, by accepting a plurality of types of parameters, the number of modules up to the location where a ground fault has occurred can be specifically specified according to the parameters given when the measurement by the measuring device 300 is performed.

[0099] [[ID=1 / 5]] Furthermore, in the first embodiment, when the open-circuit voltage of the module and the number of years since the module was put into use are input as parameters, the number of modules up to the location where a ground fault has occurred is calculated using a coefficient indicating the degree of deterioration of the module. Therefore, according to the first embodiment, it is possible to calculate the number of modules up to the location where a ground fault has occurred in consideration of the deterioration of the module, and the accuracy in specifying the location where a ground fault has occurred can be improved.

[0100] Furthermore, in the first embodiment, when calculating the ratio of the number of modules up to the location where the ground fault occurred, the terminal selected as the starting point can be chosen. Therefore, in the first embodiment, the user of the information terminal 200 can be made to understand the number of modules from the terminal closer to the location where the ground fault occurred as the starting point up to the location where the ground fault occurred.

[0101] Furthermore, in the first embodiment, when it is determined that there is a ground fault, the ratio of the number of modules up to the location where the ground fault occurred to the total number of modules included in the string 400 is displayed together with the determination result. Therefore, according to the first embodiment, the user of the information terminal 200 can be easily made to understand the location where the ground fault occurred in the string 400.

[0102] Furthermore, in the first embodiment, when it is determined that there is a ground fault, when the number of modules included in the string 400 is input, the number of modules up to the location where the ground fault occurred is displayed together with the determination result. Therefore, according to the first embodiment, the user of the information terminal 200 can be easily made to understand the number of modules from the starting point to the location where the ground fault occurred in the string 400.

[0103] Furthermore, in the first embodiment, the image data obtained by photographing the string 400 to be measured is associated with the result of the process by the ground fault determination unit 230 to obtain measurement information. Therefore, according to the first embodiment, the amount of information of the measurement information can be increased and the reliability of the information can be improved.

[0104] (Second Embodiment) The second embodiment will be described below with reference to the drawings. The difference between the second embodiment and the first embodiment is that the measurement information is managed by the server device. Therefore, in the following description of the second embodiment, the differences from the first embodiment will be described, and components having the same functional configuration as those in the first embodiment will be given the same reference numerals as those used in the description of the first embodiment, and the description thereof will be omitted.

[0105] FIG. 11 is a diagram showing an example of the system configuration of the grounding determination system according to the second embodiment. As shown in FIG. 11, the grounding determination system 100A according to the second embodiment includes an information terminal 200, a measurement device 300, an information terminal 500, and a server device 600. The information terminal 200 is an example of a first information terminal, and the information terminal 500 is an example of a second information terminal.

[0106] The information terminal 500 is an information processing device mainly used by, for example, the administrator of the string 400. The administrator of the string 400 may mainly be a business operator or a worker who performs maintenance of the string 400.

[0107] The server device 600 is an information processing device provided on the Internet line, receives measurement information from the information terminal 200, and stores the received measurement information. Note that the measurement information may be transmitted from the information storage unit 239 of the information terminal 200 to the server device 600 and stored in the server device 600. Further, the server device 600 has a notification transmission unit that transmits a notification indicating that fact to the administrator of the string 400 that is the measurement target when the determination result of the presence or absence of grounding included in the measurement information indicates "there is grounding".

[0108] Specifically, in the server device 600, management information associating the string 400 to be measured, information about the solar cell array including the string 400, and the administrator of the string 400 may be stored.

[0109] The information about the solar cell array may include, for example, information indicating the installation location of the solar cell and information for identifying each string 400 included in the solar cell array.

[0110] When it is determined that there is a ground fault in the measurement information received from the information terminal 200, the server device 600 may refer to the management information and send a notification indicating the occurrence of the ground fault and a maintenance request to the information terminal 500 of the administrator associated with the string 400 to be measured. The notification sent to the information terminal 500 may include information about the solar cell array including the string 400 where the ground fault has occurred and information indicating the location where the ground fault has occurred.

[0111] In the second embodiment, as described above, by managing the measurement information in the server device 600 and notifying the administrator of the string 400 to that effect when it is determined that there is a ground fault, the maintenance of the string 400 can be performed at an appropriate timing.

[0112] In the first and second embodiments, the ground fault determination systems 100, 100A are configured to determine the presence or absence of a ground fault in the solar cell string, but the present invention is not limited to this. The ground fault determination systems 100, 100A may be used, for example, to determine the presence or absence of a ground fault in a fuel cell having a plurality of cells or in a DC power circuit installed in a power storage station.

[0113] Also, the function of the ground fault presence / absence determination unit 234 in the first and second embodiments may be realized using, for example, an existing application.

[0114] Note that the present invention is not limited to the configurations and the like described in the above embodiments, such as combinations with other elements. Regarding these points, it is possible to make changes without departing from the spirit of the present invention, and it can be appropriately determined according to the application form.

Explanation of Reference Numerals

[0115] 100, 100A Ground fault determination system 200, 500 Information terminal 230 Ground fault determination unit 231 Communication control unit 232 Measurement value acquisition unit 233 Measurement Object Judgment Unit 234 Ground Fault Presence Judgment Unit 235 Parameter Judgment Unit 236 Ratio Calculation Unit 237 Quantity Calculation Unit 238 Display Control Unit 239 Information Storage Unit 300 Measuring Device 310 Measurement Value Transmission Unit 400 String 600 Server Device

Claims

1. A ground fault determination system including a measurement device and an information terminal that communicates with the measurement device, wherein the measurement device has a measurement value transmission unit that acquires, as measurement values, the open-circuit voltage of a solar cell string configured by connecting solar cell modules in series, the voltage between the positive electrode of the solar cell string and the ground, and the voltage between the negative electrode of the solar cell string and the ground, and transmits them to the information terminal, and the information terminal has a ground fault presence / absence determination unit that determines the presence or absence of a ground fault in the solar cell string using the measurement values received from the measurement device.

2. The information terminal has a ratio calculation unit that calculates, using the open-circuit voltage of the solar cell string, the voltage between the positive electrode of the solar cell string and the ground, and the voltage between the negative electrode of the solar cell string and the ground, the ratio of the number of modules from the positive electrode side terminal or the negative electrode side terminal of the solar cell string to the location where the ground fault has occurred, with respect to the number of solar cell modules included in the solar cell string. The ground fault determination system according to Claim 1.

3. The information terminal has a parameter determination unit that determines whether a parameter regarding the solar cell module has been input, and when the parameter has been input, has a number calculation unit that calculates, using the parameter and the ratio calculated by the ratio calculation unit, the number of modules from the positive electrode side terminal or the negative electrode side terminal of the solar cell string to the location where the ground fault has occurred, with respect to the number of solar cell modules included in the solar cell string. The ground fault determination system according to Claim 2.

4. The parameter regarding the solar cell module includes the number of solar cell modules included in the solar cell string and the open-circuit voltage of the solar cell module. The ground fault determination system according to Claim 3.

5. The parameter regarding the solar cell module includes the number of years elapsed of the solar cell module, and the number calculation unit uses a coefficient indicating the degree of deterioration according to the number of years elapsed of the solar cell module when calculating the number of modules to the location where the ground fault has occurred when the open-circuit voltage of the solar cell module and the number of years elapsed of the solar cell module are input as parameters regarding the solar cell module. The ground fault determination system according to Claim 4.

6. The number calculation unit When either the positive terminal of the solar cell string or the negative terminal of the solar cell string is selected, the number of modules from the selected terminal to the location where the ground fault occurred is calculated. The ground fault determination system according to claim 3.

7. The information terminal has a display control unit that causes the screen to display both the measured value, the determination result by the ground fault presence / absence determination unit, the parameters related to the solar cell module, the ratio calculated by the ratio calculation unit, and the number calculated by the number calculation unit. The ground fault determination system according to claim 4.

8. The information terminal has an information storage unit that stores, as measurement information, image data indicating the image displayed on the screen in a storage device. The ground fault determination system according to claim 7.

9. An information terminal that communicates with a measuring device that measures the open-circuit voltage of a solar cell string configured by connecting solar cell modules in series, the voltage between the positive electrode of the solar cell string and the ground, and the voltage between the negative electrode of the solar cell string and the ground, receives, as measured values, the open-circuit voltage of the solar cell string, the voltage between the positive electrode of the solar cell string and the ground, and the voltage between the negative electrode of the solar cell string from the measuring device, A ground fault determination program that causes a process of determining the presence or absence of a ground fault in the solar cell string using the measured values received from the measuring device to be executed.

10. A ground fault determination system including a measuring device, a first information terminal that communicates with the measuring device, a second information terminal different from the first information terminal, and a server device that communicates with the first information terminal and the second information terminal, wherein the measuring device has a measured value transmission unit that acquires, as measured values, the open-circuit voltage of a solar cell string configured by connecting solar cell modules in series, the voltage between the positive electrode of the solar cell string and the ground, and the voltage between the negative electrode of the solar cell string and the ground, and transmits them to the information terminal, wherein the first information terminal has a ground fault presence / absence determination unit that determines the presence or absence of a ground fault in the solar cell string using the measured values received from the measuring device, and an information storage unit that transmits and stores measurement information including the determination result by the ground fault presence / absence determination unit and the measured values to the server device, wherein the server device A ground fault determination system having a notification transmission unit that, when the determination result by the ground fault presence / absence determination unit in the measurement information received from the first information terminal indicates that there is a ground fault, transmits a notification indicating that fact to the second information terminal.

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