Ground insulation impedance fault positioning method, device and equipment for multi-path photovoltaic access

Abstract

The invention relates to the technical field of photovoltaic inverter grid connection, and discloses a multi-path photovoltaic access ground insulation impedance fault positioning method, device and equipment, the output end of a multi-path photovoltaic is connected with a photovoltaic inverter, the method comprises the following steps: after the photovoltaic inverter is connected to the grid, collecting the leakage current and photovoltaic input voltage of the output end of the multi-path photovoltaic; extracting a leakage current direct current component from the leakage current; and traversing the photovoltaic input voltage of each path of photovoltaic, positioning the positive electrode or the negative electrode of the corresponding path of photovoltaic with abnormal insulation resistance to ground according to the magnitude change or the positive and negative of the leakage current in the traversing process, and detecting the insulation resistance to ground of multiple paths of photovoltaic on line based on the photovoltaic input voltage, the positive electrode or the negative electrode of the corresponding path of photovoltaic and the direct current component of the leakage current. According to the method, the purpose of accurately positioning the impedance abnormal photovoltaic string through multi-path photovoltaic input is achieved, and the problems that online ground insulation impedance cannot be achieved, and fault positioning cannot be conducted on the insulation impedance abnormal condition are solved.

Description

Technical Field

[0001] The present invention relates to the technical field of photovoltaic inverter grid connection, and in particular to a method, device and equipment for locating ground insulation impedance faults of multi-path photovoltaic access. Background Art

[0002] Currently, the bridge method is used to detect the insulation impedance of photovoltaic modules to ground before the photovoltaic inverter is connected to the grid. This only ensures that the impedance of the photovoltaic inverter is normal before the grid is connected, but the bridge method cannot detect the insulation impedance to ground after the grid is connected; when there are multiple photovoltaic inputs, the bridge method cannot locate the fault of abnormal insulation impedance. Summary of the invention

[0003] In view of this, the present invention provides a method, device and equipment for locating the insulation impedance fault of multiple photovoltaic accesses to the ground, so as to solve the problem that the online insulation impedance to the ground and the insulation impedance abnormality cannot be realized and the fault location cannot be realized.

[0004] In a first aspect, the present invention provides a method for locating ground insulation impedance faults of multi-channel photovoltaic access, wherein the output ends of the multi-channel photovoltaics are connected to a photovoltaic inverter, and the method comprises:

[0005] When the photovoltaic inverter is connected to the grid, the leakage current and photovoltaic input voltage of multiple photovoltaic output ends are collected, and the DC component of the leakage current is extracted from the leakage current;

[0006] Traverse the photovoltaic input voltage of each photovoltaic line, and locate the positive or negative pole of the photovoltaic line with abnormal insulation impedance to ground according to the change of leakage current or positive or negative during the traversal process;

[0007] The insulation impedance of multiple photovoltaics to ground is detected online based on the photovoltaic input voltage, the positive or negative pole of the corresponding photovoltaic and the DC component of the leakage current.

[0008] The method for locating the insulation impedance fault to the ground of multiple photovoltaic accesses provided by the present invention collects the leakage current and the photovoltaic input voltage of multiple photovoltaic output ends after the photovoltaic inverter is connected to the grid, and extracts the leakage current DC component from the leakage current; by traversing the photovoltaic input voltage of each photovoltaic, the positive or negative pole of the photovoltaic with abnormal insulation impedance to the ground of the corresponding path is located according to the change in the magnitude of the leakage current or the positive or negative position during the traversal process, so that the purpose of accurately locating the photovoltaic string with abnormal impedance of the multiple photovoltaic inputs is achieved, and the purpose of online detection of the insulation impedance to the ground of multiple photovoltaics based on the photovoltaic input voltage, the positive or negative pole of the corresponding photovoltaic path and the DC component of the leakage current is achieved, and the problem of not being able to achieve online insulation impedance to the ground and not being able to achieve fault location of insulation impedance abnormality is solved.

[0009] In an optional implementation manner, extracting the leakage current DC component from the leakage current includes:

[0010] The leakage current is processed by notch filtering and low-pass filtering in sequence to filter out the AC component of the leakage current and extract the DC component of the leakage current.

[0011] The method for locating the insulation impedance fault of multiple photovoltaic accesses provided by the present invention sequentially performs notch filtering and low-pass filtering on the leakage current, filters out the AC component of the leakage current, and accurately extracts the DC component of the leakage current, thus providing conditions for the subsequent calculation of the insulation impedance to the ground.

[0012] In an optional implementation, the photovoltaic input voltage includes a photovoltaic positive voltage to ground and a photovoltaic negative voltage to ground; the photovoltaic inverter includes a DC bus;

[0013] Traverse the photovoltaic input voltage of each photovoltaic line, and locate the positive or negative pole of the corresponding photovoltaic line where the abnormal insulation impedance to the ground occurs according to the change of leakage current or positive and negative positioning during the traversal process, including:

[0014] Obtain the DC bus voltage of the photovoltaic inverter, and calculate the photovoltaic positive voltage to ground and the photovoltaic negative voltage to ground based on the photovoltaic input voltage and the DC bus voltage;

[0015] Traverse the photovoltaic input voltage of each photovoltaic line, and judge whether the insulation impedance of the positive pole of the photovoltaic line to the ground is abnormal based on the positive and negative values ​​of the photovoltaic positive voltage to the ground and the positive and negative values ​​of the leakage current; or traverse the photovoltaic input voltage of each photovoltaic line, and judge whether the insulation impedance of the negative pole of the photovoltaic line to the ground is abnormal based on the negative voltage of the photovoltaic line to the ground and the positive and negative values ​​of the leakage current;

[0016] When the insulation impedance to ground of the corresponding photovoltaic road is abnormal, the photovoltaic input voltage is changed, and the positive or negative pole of the corresponding photovoltaic road where the insulation impedance to ground abnormality occurs is located according to the change in the leakage current.

[0017] The method for locating insulation impedance faults of multiple photovoltaic accesses to the ground provided by the present invention requires voltage traversal (changing the photovoltaic input voltage) for multiple photovoltaic inputs. Through voltage traversal and combined with the change in the size and positive and negative of the leakage current, it is possible to accurately locate whether insulation impedance abnormality occurs between the photovoltaic positive and the ground on the corresponding path. If insulation impedance abnormality does not occur between the photovoltaic positive and the ground, the insulation impedance abnormality occurs between the photovoltaic negative and the ground, thereby overcoming the defect that the prior art cannot locate insulation impedance abnormality faults after the photovoltaic inverter is connected to the grid.

[0018] In an optional implementation, calculating the photovoltaic positive voltage to ground and the photovoltaic negative voltage to ground based on the photovoltaic input voltage and the DC bus voltage includes:

[0019] Calculate half of the DC bus voltage to get the PV negative voltage to ground;

[0020] The difference between the PV input voltage and the PV negative voltage to ground is calculated to obtain the PV positive voltage to ground.

[0021] The method for locating the insulation impedance fault of multiple photovoltaic accesses provided by the present invention accurately calculates the negative voltage of photovoltaics to the ground through the relationship between the DC bus voltage of the photovoltaic inverter and the negative voltage of photovoltaics to the ground, and then accurately calculates the positive voltage of photovoltaics to the ground, thereby providing conditions for the subsequent positioning of the abnormal insulation impedance of the corresponding photovoltaics to the ground.

[0022] In an optional implementation, judging whether the insulation impedance of the positive electrode of the photovoltaic device to the ground is abnormal based on the positive and negative values ​​of the photovoltaic device to the ground and the positive and negative values ​​of the leakage current includes:

[0023] Determine whether the positive voltage of the photovoltaic to the ground is positive. If it is positive and the leakage current is negative, it is determined that the insulation impedance of the positive pole of the photovoltaic to the ground of the corresponding road is abnormal; otherwise, the insulation impedance of the positive pole of the photovoltaic to the ground of the corresponding road is normal;

[0024] Based on the negative voltage of the photovoltaic power plant to the ground and the positive and negative leakage current, the negative insulation impedance of the photovoltaic power plant to the ground is judged to be abnormal, including:

[0025] The negative voltage of the photovoltaic to the ground is a negative value, and the positive and negative values ​​of the leakage current are judged. When the leakage current is a negative value, it is judged that the insulation impedance of the negative pole of the photovoltaic to the ground of the corresponding road is abnormal; otherwise, the insulation impedance of the negative pole of the photovoltaic to the ground of the corresponding road is normal.

[0026] The method for locating the insulation impedance fault of multiple photovoltaic accesses provided by the present invention achieves the purpose of accurately locating the insulation impedance anomaly of the corresponding photovoltaic accesses according to the relationship between the collection direction of the leakage current and the positive photovoltaic voltage to the ground and the negative photovoltaic voltage to the ground.

[0027] In an optional implementation, when the insulation impedance to ground of the corresponding photovoltaic path is abnormal, changing the magnitude of the photovoltaic input voltage, and locating the positive or negative pole of the corresponding photovoltaic path where the insulation impedance to ground abnormality occurs according to the change in the magnitude of the leakage current includes:

[0028] When the insulation impedance to ground of the corresponding photovoltaic road is abnormal, the photovoltaic input voltage is pulled down. When the leakage current of the corresponding road increases or decreases, the insulation impedance to ground abnormality occurs at the positive pole of the corresponding photovoltaic road; when the leakage current remains unchanged, the insulation impedance to ground abnormality occurs at the negative pole of the corresponding photovoltaic road.

[0029] The method for locating the insulation impedance fault to ground of multiple photovoltaic accesses provided by the present invention, for multiple photovoltaic string inputs or multiple input voltages that are different, lowers the input voltage of each photovoltaic channel one by one according to the leakage current direction and the photovoltaic positive voltage to ground, and finds the positive and negative poles of the photovoltaic channel corresponding to the abnormal insulation impedance to ground based on the change of leakage current during the traversal process, thereby realizing the precise positioning of the photovoltaic module fault.

[0030] In an optional implementation, the online detection of the insulation impedance of multiple photovoltaic channels to ground based on the photovoltaic input voltage, the positive or negative pole of the corresponding photovoltaic channel and the DC component of the leakage current includes:

[0031] The positive or negative pole of the corresponding photovoltaic circuit is detected online, and the insulation impedance to ground of multiple photovoltaic circuits is obtained based on the ratio of the photovoltaic positive voltage to ground or the photovoltaic negative voltage to ground to the DC component of the leakage current.

[0032] The method for locating the insulation impedance fault of multiple photovoltaic accesses provided by the present invention achieves the effect of online monitoring the insulation impedance of multiple photovoltaics to the ground by online detecting the positive pole or negative pole of the corresponding photovoltaic, and based on the ratio of the photovoltaic positive voltage to the ground or the photovoltaic negative voltage to the ground and the DC component of the leakage current. The insulation impedance value to the ground can be monitored in real time after the photovoltaic inverter is connected to the grid, providing conditions for the subsequent positioning of the abnormal insulation impedance to the ground.

[0033] In a second aspect, the present invention provides a device for locating ground insulation impedance faults for multi-channel photovoltaic access, wherein the output ends of the multi-channel photovoltaics are connected to a photovoltaic inverter, and the device comprises:

[0034] The leakage current collection and extraction module is used to collect the leakage current and photovoltaic input voltage of multiple photovoltaic output ends after the photovoltaic inverter is connected to the grid, and extract the leakage current DC component from the leakage current;

[0035] The fault location module is used to traverse the photovoltaic input voltage of each photovoltaic circuit, and locate the positive or negative pole of the corresponding photovoltaic circuit where the insulation impedance to the ground is abnormal according to the change in the magnitude of the leakage current or the positive or negative position during the traversal process;

[0036] The online detection module for insulation resistance to ground is used for online detection of insulation resistance to ground of multiple photovoltaic channels based on photovoltaic input voltage, positive or negative pole of corresponding photovoltaic channels and DC component of leakage current.

[0037] In a third aspect, the present invention provides a computer device, comprising: a memory and a processor, the memory and the processor being communicatively connected to each other, the memory storing computer instructions, and the processor executing the method for locating ground insulation impedance faults of multi-channel photovoltaic accesses according to the first aspect or any corresponding embodiment thereof by executing the computer instructions.

[0038] In a fourth aspect, the present invention provides a computer-readable storage medium having computer instructions stored thereon, the computer instructions being used to enable a computer to execute the method for locating ground insulation impedance faults of multi-channel photovoltaic accesses according to the first aspect or any corresponding embodiment thereof. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0040] Figure 1 It is a schematic flow chart of a method for locating ground insulation impedance faults of multi-path photovoltaic access according to an embodiment of the present invention;

[0041] Figure 2 is a flow chart of another method for locating ground insulation impedance faults of multi-path photovoltaic access according to an embodiment of the present invention;

[0042] Figure 3 It is a flow chart of another method for locating ground insulation impedance faults of multi-path photovoltaic access according to an embodiment of the present invention;

[0043] Figure 4 It is a flow chart of another method for locating ground insulation impedance faults of multi-channel photovoltaic access according to an embodiment of the present invention;

[0044] Figure 5 is a structural block diagram of a device for locating ground insulation impedance faults of multi-path photovoltaic access according to an embodiment of the present invention;

[0045] Figure 6 It is a schematic diagram of the hardware structure of a computer device according to an embodiment of the present invention. DETAILED DESCRIPTION

[0046] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0047] According to an embodiment of the present invention, an embodiment of a method for locating ground insulation impedance faults of multi-channel photovoltaic access is provided. It should be noted that the steps shown in the flowchart of the accompanying drawings can be executed in a computer system such as a set of computer executable instructions, and although a logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in an order different from that shown here.

[0048] In this embodiment, a method for locating ground insulation impedance faults of multi-channel photovoltaic access is provided, which can be used in a photovoltaic inverter grid-connected circuit. The photovoltaic inverter grid-connected circuit includes multiple photovoltaic channels, the output ends of the multiple photovoltaic channels are connected to the photovoltaic inverter, and each photovoltaic channel is composed of multiple photovoltaic modules connected in series. Figure 1 is a flow chart of a method for locating ground insulation impedance faults of multi-path photovoltaic access according to an embodiment of the present invention. Figure 1 As shown, the process includes the following steps:

[0049] Step S101, after the photovoltaic inverter is connected to the grid, leakage currents and photovoltaic input voltages of multiple photovoltaic output terminals are collected, and a leakage current DC component is extracted from the leakage current.

[0050] Specifically, photovoltaic inverter grid connection refers to connecting multiple photovoltaic modules to the conventional power grid to jointly undertake the power supply task. When there is sunlight, the photovoltaic inverter converts the DC power generated by multiple photovoltaic modules into sinusoidal AC power. The generated AC power can directly supply the AC load, and then input the remaining electric energy into the power grid, or directly connect all the generated electric energy to the power grid. When there is no sun, the load power is all supplied by the power grid. Leakage current refers to the current spontaneously generated by the photovoltaic module under the open circuit voltage working state and without light conditions. The leakage current includes DC component and AC component.

[0051] When the photovoltaic inverter is connected to the conventional power grid, the leakage current and photovoltaic input voltage of multiple photovoltaic output ends are collected through the Hall collector, and the DC component of the leakage current is extracted from the leakage current.

[0052] Step S102, traversing the photovoltaic input voltage of each photovoltaic line, and locating the positive or negative pole of the photovoltaic line with abnormal insulation impedance to ground according to the change in the magnitude or positive or negative of the leakage current during the traversal process.

[0053] Specifically, for multiple photovoltaic string inputs or multiple input voltages are different, the input voltage of each photovoltaic line is traversed one by one according to the leakage current direction and PV+ ground voltage, and the positive and negative poles of the photovoltaic line corresponding to the abnormal insulation impedance to ground are found according to the change in the magnitude of the leakage current or the positive and negative judgment during the traversal process. Each photovoltaic line is composed of multiple photovoltaic modules connected in series, and the positive pole of the first photovoltaic module is used as the positive pole of each photovoltaic line, and the negative pole of the last photovoltaic module is used as the negative pole of each photovoltaic line.

[0054] Step S103, online detection of the insulation impedance of multiple photovoltaic channels to ground based on the photovoltaic input voltage, the positive or negative pole of the corresponding photovoltaic channel and the DC component of the leakage current.

[0055] Specifically, the insulation impedance to ground refers to the resistance value between the output terminals of multiple photovoltaics and the ground, also known as "ground resistance". The insulation impedance to ground has a functional relationship with the photovoltaic input voltage and the DC component of the leakage current. When the leakage current is larger, the insulation impedance to ground is larger. The insulation impedance to ground of multiple photovoltaics is detected online through the photovoltaic input voltage, the positive or negative pole of the corresponding photovoltaic and the DC component of the leakage current.

[0056] The method for locating the insulation impedance fault to ground of multiple photovoltaic accesses provided in this embodiment collects the leakage current and photovoltaic input voltage of multiple photovoltaic output ends after the photovoltaic inverter is connected to the grid, and extracts the leakage current DC component from the leakage current; by traversing the photovoltaic input voltage of each photovoltaic channel, the positive or negative pole of the photovoltaic with abnormal insulation impedance to ground of the corresponding channel is located according to the change in the magnitude of the leakage current or the positive or negative position during the traversal process, so that the purpose of accurately locating the photovoltaic string with abnormal impedance of multiple photovoltaic inputs is achieved, and the purpose of online detection of the insulation impedance to ground of multiple photovoltaic channels based on the photovoltaic input voltage, the positive or negative pole of the corresponding photovoltaic channel and the DC component of the leakage current is achieved, and the problem of not being able to achieve online insulation impedance to ground and not being able to achieve fault location of insulation impedance abnormality is solved.

[0057] In this embodiment, a method for locating ground insulation impedance faults of multi-channel photovoltaic access is provided, which can be used in a photovoltaic inverter grid-connected circuit. The photovoltaic inverter grid-connected circuit includes multiple photovoltaic channels, the output ends of the multiple photovoltaic channels are connected to the photovoltaic inverter, and each photovoltaic channel is composed of multiple photovoltaic modules connected in series. Figure 2 is a flow chart of a method for locating ground insulation impedance faults of multi-path photovoltaic access according to an embodiment of the present invention. Figure 2 As shown, the process includes the following steps:

[0058] Step S201, after the photovoltaic inverter is connected to the grid, the leakage current and photovoltaic input voltage of multiple photovoltaic output terminals are collected, and the leakage current DC component is extracted from the leakage current.

[0059] Specifically, the photovoltaic input voltage of the multiple photovoltaic output terminals refers to the total DC voltage output by the solar panels in each photovoltaic module. The above step S201 includes:

[0060] Step a. Perform notch filtering and low-pass filtering on the leakage current in sequence to filter out the AC component of the leakage current and extract the DC component of the leakage current.

[0061] The notch filter is implemented by a notch filter, and the function of the notch filter is to suppress or eliminate the signal of a specific frequency, for example, to eliminate the AC component of 150Hz. The specific content of the notch filter is referred to the relevant technical content, and will not be repeated here.

[0062] Low-pass filtering is implemented by a low-pass filter. The function of low-pass filtering is to allow low-frequency signals to pass through, while suppressing high-frequency signals, further eliminating the AC component of high-frequency signals, and finally extracting the DC component of leakage current. Step S202, traverse the photovoltaic input voltage of each photovoltaic line, and locate the positive or negative pole of the photovoltaic line with abnormal insulation impedance to ground according to the change of leakage current or positive or negative position during the traversal process. For details, please refer to Figure 1 Step S102 of the illustrated embodiment will not be described in detail here.

[0063] Step S203, online detection of the insulation impedance of multiple photovoltaic channels to ground based on the photovoltaic input voltage, the positive or negative pole of the corresponding photovoltaic channel and the DC component of the leakage current.

[0064] Specifically, the above step S203 includes:

[0065] Step b. Online detection of the positive or negative pole of the corresponding photovoltaic circuit, and obtaining the insulation impedance of the photovoltaic circuits to the ground based on the ratio of the photovoltaic positive voltage to the ground or the photovoltaic negative voltage to the ground to the DC component of the leakage current.

[0066] Specifically, the formula for calculating the insulation resistance to ground is as follows:

[0067] Insulation impedance to ground = abnormal impedance voltage / DC component of leakage current;

[0068] The abnormal impedance voltage is the positive voltage of the photovoltaic device to the ground or the negative voltage of the photovoltaic device to the ground.

[0069] When the insulation impedance to ground is abnormal at the positive pole of the corresponding photovoltaic circuit, the value of the insulation impedance to ground is calculated by the following formula:

[0070] R+=U PV+ / I gfci ;

[0071] When the insulation impedance to ground is abnormal at the negative pole of the corresponding photovoltaic road, the value of the insulation impedance to ground is calculated by the following formula:

[0072] R-=U PV- / I gfci ;

[0073] Where: R+ is the insulation impedance to ground when the abnormality occurs at the positive pole of the corresponding photovoltaic road, R- is the insulation impedance to ground when the abnormality occurs at the negative pole of the corresponding photovoltaic road, I gfci is the DC component of the leakage current. PV+ and U PV- They are the positive voltage of photovoltaic to ground and the negative voltage of photovoltaic to ground respectively.

[0074] The method for locating the insulation impedance fault of multiple photovoltaic accesses provided in this embodiment performs notch filtering and low-pass filtering on the leakage current in sequence, filters out the AC component of the leakage current, and accurately extracts the DC component of the leakage current, providing conditions for the subsequent calculation of the insulation impedance to the ground. The effect of online monitoring of the insulation impedance to the ground of multiple photovoltaics is achieved by online detection of the ratio of the photovoltaic positive voltage to the ground or the photovoltaic negative voltage to the ground and the DC component of the leakage current. The insulation impedance value to the ground can be monitored in real time after the photovoltaic inverter is connected to the grid, providing conditions for the subsequent location of abnormal insulation impedance to the ground.

[0075] In this embodiment, a method for locating ground insulation impedance faults of multi-channel photovoltaic access is provided, which can be used in a photovoltaic inverter grid-connected circuit. The photovoltaic inverter grid-connected circuit includes multiple photovoltaic channels, the output ends of the multiple photovoltaic channels are connected to the photovoltaic inverter, and each photovoltaic channel is composed of multiple photovoltaic modules connected in series. Figure 3 is a flow chart of a method for locating ground insulation impedance faults of multi-path photovoltaic access according to an embodiment of the present invention. Figure 3 As shown, the process includes the following steps:

[0076] Step S301: After the photovoltaic inverter is connected to the grid, the leakage current and photovoltaic input voltage of multiple photovoltaic output terminals are collected, and the DC component of the leakage current is extracted from the leakage current. Figure 2 Step S201 of the illustrated embodiment will not be described in detail here.

[0077] Step S302, traverse the photovoltaic input voltage of each photovoltaic line, and locate the positive or negative pole of the photovoltaic line with abnormal insulation impedance to ground according to the change of leakage current or positive or negative during the traversal process.

[0078] Specifically, the photovoltaic input voltage includes a photovoltaic positive voltage to ground and a photovoltaic negative voltage to ground; the photovoltaic inverter includes a DC bus; the above step S302 includes:

[0079] Step S3021, obtaining the DC bus voltage of the photovoltaic inverter, and calculating the photovoltaic positive voltage to ground and the photovoltaic negative voltage to ground based on the photovoltaic input voltage and the DC bus voltage.

[0080] Specifically, the photovoltaic input voltage is recorded as PV voltage, and the photovoltaic positive voltage to ground and the photovoltaic negative voltage to ground are recorded as PV+ voltage to ground or U PV+ and PV-to-ground voltage or U PV- .

[0081] In some optional implementations, the above step S3021 includes:

[0082] Step a1, calculate half of the DC bus voltage to obtain the PV negative voltage to ground.

[0083] Specifically, the formula for calculating the negative photovoltaic voltage to ground is as follows:

[0084] PV-to-ground voltage = U bus / 2;

[0085] Among them, U bus Indicates the DC bus voltage.

[0086] Step a2, calculating the difference between the photovoltaic input voltage and the photovoltaic negative voltage to ground to obtain the photovoltaic positive voltage to ground.

[0087] Specifically, the formula for calculating the photovoltaic voltage to ground is as follows:

[0088] PV+voltage to ground=PV voltage-PV-voltage to ground.

[0089] The method for locating the insulation impedance fault of multiple photovoltaic accesses provided in this embodiment accurately calculates the negative voltage of photovoltaic accesses to the ground through the relationship between the DC bus voltage of the photovoltaic inverter and the negative voltage of photovoltaic accesses to the ground, and then accurately calculates the positive voltage of photovoltaic accesses to the ground, thereby providing conditions for subsequently locating the abnormal insulation impedance of the corresponding photovoltaic accesses to the ground.

[0090] Step S3022, traverse the photovoltaic input voltage of each photovoltaic line, and judge whether the insulation impedance of the positive pole to the ground of the corresponding photovoltaic line is abnormal based on the positive and negative values ​​of the photovoltaic positive voltage to the ground and the positive and negative values ​​of the leakage current; or, traverse the photovoltaic input voltage of each photovoltaic line, and judge whether the insulation impedance of the negative pole to the ground of the corresponding photovoltaic line is abnormal based on the negative photovoltaic voltage to the ground and the positive and negative values ​​of the leakage current.

[0091] In some optional implementations, the traversing of the photovoltaic input voltage of each photovoltaic circuit in the above step S3022 and judging whether the insulation impedance of the positive electrode to the ground of the corresponding photovoltaic circuit is abnormal based on the positive and negative values ​​of the photovoltaic positive voltage to the ground and the positive and negative values ​​of the leakage current include:

[0092] Step b1, determine whether the positive voltage of the photovoltaic to the ground is positive. When it is positive and the leakage current is negative, it is determined that the insulation impedance of the positive pole of the photovoltaic to the ground of the corresponding road is abnormal; otherwise, the insulation impedance of the positive pole of the photovoltaic to the ground of the corresponding road is normal.

[0093] Step b2, determine whether the positive voltage of the photovoltaic to the ground is a negative value. When it is a negative value and the leakage current is a positive value, it is determined that the insulation impedance of the positive electrode of the photovoltaic to the ground of the corresponding road is abnormal; otherwise, the insulation impedance of the positive electrode of the photovoltaic to the ground of the corresponding road is normal.

[0094] Specifically, according to the collection direction of the leakage current Hall collector, when the PV+ voltage to ground is greater than 0 and the leakage current is negative, the positive insulation impedance to ground of the photovoltaic road is abnormal; otherwise, the leakage current is positive, and the positive insulation impedance to ground of the corresponding photovoltaic road is normal. When the PV+ voltage to ground is less than 0 and the leakage current is positive, the positive insulation impedance to ground of the photovoltaic road is abnormal; otherwise, the leakage current is negative, and the positive insulation impedance to ground of the corresponding photovoltaic road is normal.

[0095] In some optional implementations, the photovoltaic input voltage and photovoltaic negative ground voltage of each photovoltaic path are traversed in the above step S3022, and judging whether the insulation impedance of the negative electrode of the photovoltaic path to the ground is abnormal based on the positive and negative photovoltaic negative voltage to the ground and the leakage current includes:

[0096] Step b3, the negative voltage of the photovoltaic to the ground is negative, and the positive and negative values ​​of the leakage current are judged. When the leakage current is negative, it is judged that the insulation impedance of the negative pole of the photovoltaic to the ground of the corresponding road is abnormal; otherwise, the insulation impedance of the negative pole of the photovoltaic to the ground of the corresponding road is normal.

[0097] Specifically, when the PV-to-ground voltage is always less than 0 and the leakage current is negative, the insulation impedance of the corresponding photovoltaic to the ground is abnormal. On the contrary, when the leakage current is positive, the insulation impedance of the corresponding photovoltaic to the ground is normal.

[0098] The method for locating the insulation impedance fault of multiple photovoltaic accesses provided in this embodiment achieves the purpose of accurately locating the insulation impedance anomaly of the corresponding photovoltaic accesses based on the relationship between the collection direction of the leakage current and the positive photovoltaic voltage to the ground and the negative photovoltaic voltage to the ground.

[0099] Step S3023, when the insulation impedance to ground of the corresponding photovoltaic path is abnormal, the photovoltaic input voltage is changed, and the positive or negative pole of the corresponding photovoltaic path where the insulation impedance to ground abnormality occurs is located according to the change in the leakage current.

[0100] In some optional implementations, the above step S3023 includes:

[0101] Step c. When the insulation impedance to ground of the corresponding photovoltaic road is abnormal, the photovoltaic input voltage is pulled down. When the leakage current of the corresponding road increases or decreases, the insulation impedance to ground abnormality occurs at the positive pole of the corresponding photovoltaic road; when the leakage current remains unchanged, the insulation impedance to ground abnormality occurs at the negative pole of the corresponding photovoltaic road.

[0102] Specifically, when the photovoltaic input voltage is small, according to the voltage calculation, the PV+ ground voltage is a negative value. In this way, the positive or negative leakage current cannot be used to determine whether the ground insulation impedance abnormality occurs at the positive or negative pole of the photovoltaic. The PV input voltage needs to be lowered (the lower the voltage, the greater the leakage current change). Specifically, reduce the photovoltaic input voltage. At this time, if the leakage current increases or decreases, the ground insulation impedance abnormality appears at the positive pole of the corresponding photovoltaic. If the leakage current remains unchanged, continue to traverse other photovoltaic inputs. If the ground insulation impedance abnormality does not appear at the positive pole of the photovoltaic after the traversal is completed, the ground insulation impedance abnormality appears at the negative pole of the photovoltaic.

[0103] It can be seen from the above step S3023 that for multiple photovoltaic string inputs or multiple input voltages are different, each photovoltaic input voltage is traversed one by one according to the leakage current direction and the PV+ ground voltage. According to the change of leakage current during the traversal process, the positive or negative pole of the photovoltaic corresponding to the abnormal insulation impedance to the ground is found, thereby realizing the precise positioning of the photovoltaic component fault.

[0104] Step S303, based on the photovoltaic input voltage, the positive or negative pole of the corresponding photovoltaic path and the DC component of the leakage current, the insulation impedance of the multiple photovoltaic paths to the ground is detected online. Figure 2 Step S203 of the illustrated embodiment will not be described in detail here.

[0105] The method for locating insulation impedance faults of multiple photovoltaic accesses to ground provided in this embodiment requires voltage traversal (changing the photovoltaic input voltage) for multiple photovoltaic inputs. Through voltage traversal and combined with the change in the size and positive and negative of the leakage current, it is possible to accurately locate whether insulation impedance abnormality occurs between the photovoltaic positive and the ground on the corresponding photovoltaic path. If insulation impedance abnormality does not occur between the photovoltaic positive and the ground, then insulation impedance abnormality occurs between the photovoltaic negative and the ground, thereby overcoming the defect that the prior art cannot locate insulation impedance abnormality faults after the photovoltaic inverter is connected to the grid.

[0106] As one or more specific application embodiments of the present invention, Figure 4 The method for locating the ground insulation impedance fault of multi-path photovoltaic access provided by the present invention is further described in detail, and the specific steps are as follows:

[0107] A. The leakage current is sampled by the Hall collector, and the DC component of the leakage current is filtered out. The insulation impedance to ground is calculated according to the insulation impedance to ground = abnormal impedance voltage / DC component of the leakage current. The abnormal impedance voltage is the positive voltage of the photovoltaic to ground or the negative voltage of the photovoltaic to ground. In order to accurately calculate the insulation impedance to ground, the collected leakage current needs to be filtered to filter out the influence of the AC component.

[0108] B. Calculate the PV+ voltage to ground and PV- voltage to ground of all photovoltaic lines through the PV input voltage of each line, i.e., the PV voltage. Among them, the PV- voltage to ground is equal to U bus / 2, PV+ voltage to ground equals PV voltage minus PV- voltage to ground, U bus is the DC bus voltage.

[0109] C. According to the direction of leakage current collected by the Hall collector, when the voltage of PV+ to ground is positive, when the insulation impedance to ground of the road is abnormal, the leakage current is negative. On the contrary, when the leakage current is positive, the insulation impedance to ground of the corresponding road is normal. When the voltage of PV+ to ground is negative, when the insulation impedance to ground of the road is abnormal, the leakage current is positive. On the contrary, when the leakage current is negative, the insulation impedance to ground of the corresponding road is normal.

[0110] The PV-to-ground voltage is always less than 0. If the insulation impedance to ground is abnormal, the leakage current will be negative. Otherwise, the leakage current will be positive, and the insulation impedance to ground of the corresponding photovoltaic is normal.

[0111] D. When the PV input voltage is small, according to the voltage calculation, the PV+ voltage to ground is negative. Through the positive and negative leakage current, it is impossible to determine whether the impedance abnormality occurs at the positive or negative pole of each PV. It is necessary to lower the PV input voltage (the lower the voltage, the greater the leakage current change) to reduce the PV+ voltage to ground. At this time, if the leakage current increases or decreases, the insulation impedance abnormality to ground appears at the positive pole of the corresponding PV. If the leakage current remains unchanged, the insulation impedance abnormality to ground appears at the negative pole of the corresponding PV.

[0112] It can be seen from the above step D that for multiple photovoltaic string inputs or multiple input voltages are different, the photovoltaic input voltage of each photovoltaic is traversed one by one. Through voltage traversal and combined with the change in the size and positive and negative of the leakage current, it is possible to accurately locate whether the insulation impedance abnormality of the corresponding photovoltaic is facing the ground. If the insulation impedance abnormality does not occur between the photovoltaic and the ground, the insulation impedance abnormality occurs between the photovoltaic and the ground, thereby overcoming the defect that the prior art cannot locate the insulation impedance abnormality fault after the photovoltaic inverter is connected to the grid.

[0113] The method for locating the insulation impedance fault to ground of multi-channel photovoltaic access provided in this embodiment detects the insulation impedance to ground of photovoltaic components in real time after the photovoltaic inverter is connected to the grid, locates the fault, and identifies the insulation impedance to ground abnormality of the photovoltaic positive or negative pole.

[0114] In this embodiment, a device for locating ground insulation impedance faults for multi-channel photovoltaic access is also provided, which is used to implement the above embodiments and preferred implementations, and will not be repeated for what has been described. As used below, the term "module" can implement a combination of software and / or hardware for a predetermined function. Although the device described in the following embodiments is preferably implemented in software, the implementation of hardware, or a combination of software and hardware, is also possible and conceivable.

[0115] This embodiment provides a device for locating ground insulation impedance faults in a multi-channel photovoltaic access system. The output ends of the multi-channel photovoltaics are connected to a photovoltaic inverter, such as Figure 5 As shown, including:

[0116] The leakage current collection and extraction module 501 is used to collect leakage currents and photovoltaic input voltages at multiple photovoltaic output terminals after the photovoltaic inverter is connected to the grid, and to extract the leakage current DC component from the leakage current.

[0117] The fault location module 502 is used to traverse the photovoltaic input voltage of each photovoltaic line, and locate the positive or negative pole of the corresponding photovoltaic line where the insulation impedance to the ground is abnormal according to the change in the magnitude of the leakage current or the positive or negative position during the traversal process;

[0118] The insulation impedance to ground online detection module 503 is used to detect the insulation impedance to ground of multiple photovoltaic channels online based on the photovoltaic input voltage, the positive or negative pole of the corresponding photovoltaic channel and the DC component of the leakage current.

[0119] In some optional implementations, the leakage current acquisition and extraction module 501 includes:

[0120] The filtering unit is used to perform notch filtering and low-pass filtering on the leakage current in sequence, filter out the AC component of the leakage current, and extract the DC component of the leakage current.

[0121] In some optional implementations, the photovoltaic input voltage includes a photovoltaic positive voltage to ground and a photovoltaic negative voltage to ground; the photovoltaic inverter includes a DC bus; and the fault location module 502 includes:

[0122] The photovoltaic positive and negative voltage-to-ground calculation unit is used to obtain the DC bus voltage of the photovoltaic inverter, and calculate the photovoltaic positive voltage-to-ground and the photovoltaic negative voltage-to-ground based on the photovoltaic input voltage and the DC bus voltage.

[0123] The corresponding photovoltaic abnormal positioning unit is used to traverse the photovoltaic positive-to-ground voltage of each photovoltaic line, and judge whether the insulation impedance of the positive pole of the photovoltaic line to the ground is abnormal based on the positive and negative values ​​of the photovoltaic positive-to-ground voltage and the positive and negative values ​​of the leakage current; or, traverse the photovoltaic negative-to-ground voltage of each photovoltaic line, and judge whether the insulation impedance of the negative pole of the photovoltaic line to the ground is abnormal based on the photovoltaic negative-to-ground voltage and the positive and negative values ​​of the leakage current.

[0124] The photovoltaic positive and negative pole abnormal positioning unit is used to change the size of the photovoltaic input voltage when the insulation impedance to the ground of the corresponding photovoltaic is abnormal, and locate the positive or negative pole of the corresponding photovoltaic where the insulation impedance to the ground abnormality occurs according to the change in the leakage current.

[0125] In some optional implementations, the photovoltaic positive and negative voltage to ground calculation unit includes:

[0126] The photovoltaic negative voltage to ground calculation subunit is used to calculate half of the DC bus voltage to obtain the photovoltaic negative voltage to ground.

[0127] The photovoltaic positive voltage to ground calculation subunit is used to calculate the difference between the photovoltaic input voltage and the photovoltaic negative voltage to ground to obtain the photovoltaic positive voltage to ground.

[0128] In some optional implementations, the corresponding photovoltaic abnormality positioning unit includes:

[0129] The first positioning subunit is used to determine whether the positive voltage of the photovoltaic to the ground is positive. When it is positive and the leakage current is negative, it is determined that the insulation impedance of the positive pole of the photovoltaic to the ground of the corresponding road is abnormal; otherwise, the insulation impedance of the positive pole of the photovoltaic to the ground of the corresponding road is normal.

[0130] The second positioning subunit is used to determine whether the positive voltage of the photovoltaic to the ground is a negative value. When it is a negative value and the leakage current is a positive value, it is determined that the insulation impedance of the positive pole of the photovoltaic to the ground of the corresponding road is abnormal; otherwise, the insulation impedance of the positive pole of the photovoltaic to the ground of the corresponding road is normal.

[0131] The third positioning sub-unit is used to judge the positive and negative values ​​of the leakage current when the negative voltage of the photovoltaic to the ground is negative. When the leakage current is negative, it is judged that the insulation impedance of the negative pole of the photovoltaic to the ground of the corresponding road is abnormal; otherwise, the insulation impedance of the negative pole of the photovoltaic to the ground of the corresponding road is normal.

[0132] In some optional implementations, the photovoltaic positive and negative pole abnormality positioning unit includes:

[0133] The fourth positioning subunit, when the insulation impedance to ground of the corresponding photovoltaic road is abnormal, lowers the photovoltaic input voltage. When the corresponding leakage current increases or decreases, the insulation impedance to ground abnormality occurs at the positive pole of the corresponding photovoltaic road; when the leakage current remains unchanged, the insulation impedance to ground abnormality occurs at the negative pole of the corresponding photovoltaic road.

[0134] In some optional implementations, the ground insulation impedance online detection module 503 includes:

[0135] The ground insulation impedance calculation unit is used to online detect the ratio of the photovoltaic input voltage to the DC component of the leakage current to obtain the ground insulation impedance of multiple photovoltaic channels.

[0136] The further functional description of each of the above modules and units is the same as that of the above corresponding embodiments and will not be repeated here.

[0137] The multi-channel photovoltaic access to ground insulation impedance fault location device in this embodiment is presented in the form of a functional unit, where the unit refers to an ASIC (Application Specific Integrated Circuit) circuit, a processor and memory that executes one or more software or fixed programs, and / or other devices that can provide the above functions.

[0138] The embodiment of the present invention also provides a computer device having the above Figure 5 The device for locating the insulation impedance fault to ground of multi-channel photovoltaic access is shown.

[0139] See also Figure 6 , Figure 6 is a schematic diagram of the structure of a computer device provided by an optional embodiment of the present invention, such as Figure 6 As shown, the computer device includes: one or more processors 10, a memory 20, and interfaces for connecting various components, including high-speed interfaces and low-speed interfaces. Various components are connected to each other using different buses for communication, and can be installed on a common mainboard or installed in other ways as needed. The processor can process the instructions executed in the computer device, including instructions stored in or on the memory to display the graphical information of the GUI on an external input / output device (such as, a display device coupled to the interface). In some optional embodiments, if necessary, multiple processors and / or multiple buses can be used together with multiple memories and multiple memories. Similarly, multiple computer devices can be connected, and each device provides some necessary operations (for example, as a server array, a group of blade servers, or a multi-processor system). Figure 6 A processor 10 is taken as an example.

[0140] The processor 10 may be a central processing unit, a network processor or a combination thereof. The processor 10 may further include a hardware chip. The hardware chip may be a dedicated integrated circuit, a programmable logic device or a combination thereof. The programmable logic device may be a complex programmable logic device, a field programmable gate array, a general purpose array logic or any combination thereof.

[0141] The memory 20 stores instructions executable by at least one processor 10, so that the at least one processor 10 executes the method shown in the above embodiment.

[0142] The memory 20 may include a program storage area and a data storage area, wherein the program storage area may store an operating system, an application required for at least one function; the data storage area may store data created according to the use of the computer device, etc. In addition, the memory 20 may include a high-speed random access memory, and may also include a non-transient memory, such as at least one disk storage device, a flash memory device, or other non-transient solid-state storage device. In some optional embodiments, the memory 20 may optionally include a memory remotely arranged relative to the processor 10, and these remote memories may be connected to the computer device via a network. Examples of the above-mentioned network include, but are not limited to, the Internet, an intranet, a local area network, a mobile communication network, and combinations thereof.

[0143] The memory 20 may include a volatile memory, such as a random access memory; the memory may also include a non-volatile memory, such as a flash memory, a hard disk or a solid state drive; the memory 20 may also include a combination of the above types of memory.

[0144] The computer device also includes an input device 30 and an output device 40. The processor 10, the memory 20, the input device 30 and the output device 40 may be connected via a bus or other means. Figure 6 The example of connecting through bus is taken in the following.

[0145] The input device 30 can receive input digital or character information, and generate key signal input related to the user settings and function control of the computer device, such as a touch screen, a keypad, a mouse, a track pad, a touch pad, an indicator bar, one or more mouse buttons, a trackball, a joystick, etc. The output device 40 may include a display device, an auxiliary lighting device (e.g., an LED) and a tactile feedback device (e.g., a vibration motor), etc. The above-mentioned display device includes but is not limited to a liquid crystal display, a light emitting diode, a display and a plasma display. In some optional embodiments, the display device can be a touch screen.

[0146] The embodiment of the present invention also provides a computer-readable storage medium. The method according to the embodiment of the present invention can be implemented in hardware, firmware, or can be implemented as a computer code that can be recorded in a storage medium, or can be implemented as a computer code that is originally stored in a remote storage medium or a non-temporary machine-readable storage medium and will be stored in a local storage medium through a network download, so that the method described herein can be stored in such software processing on a storage medium using a general-purpose computer, a dedicated processor, or programmable or dedicated hardware. Among them, the storage medium can be a magnetic disk, an optical disk, a read-only storage memory, a random access memory, a flash memory, a hard disk or a solid-state hard disk, etc.; further, the storage medium can also include a combination of the above types of memories. It can be understood that a computer, a processor, a microprocessor controller, or programmable hardware includes a storage component that can store or receive software or computer code. When the software or computer code is accessed and executed by a computer, a processor, or hardware, the method shown in the above embodiment is implemented.

[0147] A part of the present invention may be applied as a computer program product, such as a computer program instruction, which, when executed by a computer, can call or provide the method and / or technical solution according to the present invention through the operation of the computer. Those skilled in the art should understand that the existence of the computer program instruction in a computer-readable medium includes, but is not limited to, a source file, an executable file, an installation package file, etc., and accordingly, the way in which the computer program instruction is executed by the computer includes, but is not limited to: the computer directly executes the instruction, or the computer compiles the instruction and then executes the corresponding compiled program, or the computer reads and executes the instruction, or the computer reads and installs the instruction and then executes the corresponding installed program. Here, the computer-readable medium may be any available computer-readable storage medium or communication medium accessible to the computer.

[0148] Although the embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations are all within the scope defined by the appended claims.

Claims

1. A method for locating ground insulation impedance faults of multi-path photovoltaic access, characterized in that: The output ends of the multi-path photovoltaics are connected to a photovoltaic inverter, and the method comprises: After the photovoltaic inverter is connected to the grid, leakage currents and photovoltaic input voltages of multiple photovoltaic output terminals are collected, and a leakage current DC component is extracted from the leakage current; Traverse the photovoltaic input voltage of each photovoltaic line, and locate the positive or negative pole of the corresponding photovoltaic line where the insulation impedance to the ground is abnormal according to the change in the magnitude of the leakage current or the positive or negative position during the traversal process; The insulation impedance of multiple photovoltaics to ground is detected online based on the photovoltaic input voltage, the positive or negative pole of the corresponding photovoltaic and the DC component of the leakage current.

2. The method according to claim 1, characterized in that Extracting the leakage current DC component from the leakage current comprises: The leakage current is processed by notch filtering and low-pass filtering in sequence to filter out the AC component of the leakage current and extract the DC component of the leakage current.

3. The method according to claim 1, characterized in that The photovoltaic input voltage includes a photovoltaic positive voltage to ground and a photovoltaic negative voltage to ground; the photovoltaic inverter includes a DC bus; The photovoltaic input voltage of each photovoltaic circuit is traversed, and the positive or negative pole of the photovoltaic circuit corresponding to the abnormal insulation impedance to the ground is located according to the change of the leakage current or the positive or negative position during the traversal process, including: Obtaining a DC bus voltage of a photovoltaic inverter, and calculating a photovoltaic positive voltage to ground and a photovoltaic negative voltage to ground based on the photovoltaic input voltage and the DC bus voltage; Traverse the photovoltaic input voltage of each photovoltaic line, and judge whether the insulation impedance of the positive pole of the photovoltaic line to the ground is abnormal based on the positive and negative values ​​of the photovoltaic positive voltage to the ground and the positive and negative values ​​of the leakage current; or traverse the photovoltaic input voltage of each photovoltaic line, and judge whether the insulation impedance of the negative pole of the photovoltaic line to the ground is abnormal based on the negative voltage of the photovoltaic line to the ground and the positive and negative values ​​of the leakage current; When the insulation impedance to ground of the corresponding photovoltaic road is abnormal, the photovoltaic input voltage is changed, and the positive or negative pole of the corresponding photovoltaic road where the insulation impedance to ground abnormality occurs is located according to the change in the leakage current.

4. The method according to claim 3, characterized in that Calculating the photovoltaic positive voltage to ground and the photovoltaic negative voltage to ground based on the photovoltaic input voltage and the DC bus voltage includes: Calculate one half of the DC bus voltage to obtain the photovoltaic negative voltage to ground; The difference between the PV input voltage and the PV negative voltage to ground is calculated to obtain the PV positive voltage to ground.

5. The method according to claim 3, characterized in that: The method of judging whether the insulation impedance of the positive electrode of the photovoltaic device to the ground is abnormal based on the positive and negative values ​​of the photovoltaic device to the ground and the positive and negative values ​​of the leakage current comprises: Determine whether the positive voltage of the photovoltaic to the ground is positive. If it is positive and the leakage current is negative, it is determined that the insulation impedance of the positive pole of the photovoltaic to the ground of the corresponding road is abnormal; otherwise, the insulation impedance of the positive pole of the photovoltaic to the ground of the corresponding road is normal; Determine whether the positive voltage of the photovoltaic to the ground is negative. If it is negative and the leakage current is positive, the insulation impedance of the positive pole of the photovoltaic to the ground of the corresponding road is abnormal; otherwise, the insulation impedance of the positive pole of the photovoltaic to the ground of the corresponding road is normal; The method of judging whether the insulation impedance of the negative electrode of the photovoltaic power plant to the ground is abnormal based on the positive and negative voltage of the photovoltaic power plant to the ground and the leakage current comprises: The negative voltage of the photovoltaic to the ground is a negative value, and the positive and negative values ​​of the leakage current are judged. When the leakage current is a negative value, it is judged that the insulation impedance of the negative pole of the photovoltaic to the ground of the corresponding road is abnormal; otherwise, the insulation impedance of the negative pole of the photovoltaic to the ground of the corresponding road is normal.

6. The method according to claim 3, characterized in that When the insulation impedance of the corresponding photovoltaic power plant to the ground is abnormal, change the photovoltaic input voltage and locate the positive or negative pole of the corresponding photovoltaic power plant where the insulation impedance to the ground is abnormal according to the change in leakage current. The positive or negative pole includes: When the insulation impedance to ground of the corresponding photovoltaic road is abnormal, the photovoltaic input voltage is pulled down. When the leakage current of the corresponding road increases or decreases, the insulation impedance to ground abnormality occurs at the positive pole of the corresponding photovoltaic road; when the leakage current remains unchanged, the insulation impedance to ground abnormality occurs at the negative pole of the corresponding photovoltaic road.

7. The method according to claim 3, characterized in that Based on the photovoltaic input voltage, the positive or negative pole of the corresponding photovoltaic and the DC component of the leakage current, the online detection of the insulation impedance of multiple photovoltaics to the ground includes: The positive or negative pole of the corresponding photovoltaic circuit is detected online, and the insulation impedance to ground of multiple photovoltaic circuits is obtained based on the ratio of the photovoltaic positive voltage to ground or the photovoltaic negative voltage to ground to the DC component of the leakage current.

8. A device for locating ground insulation impedance faults for multi-path photovoltaic access, characterized in that: The output ends of the multi-path photovoltaics are connected to a photovoltaic inverter, and the device comprises: A leakage current collection and extraction module is used to collect leakage currents and photovoltaic input voltages at multiple photovoltaic output terminals after the photovoltaic inverter is connected to the grid, and to extract a leakage current DC component from the leakage current; The fault location module is used to traverse the photovoltaic input voltage of each photovoltaic circuit, and locate the positive or negative pole of the corresponding photovoltaic circuit where the insulation impedance to the ground is abnormal according to the change in the magnitude of the leakage current or the positive or negative position during the traversal process; The online detection module for insulation resistance to ground is used for online detection of insulation resistance to ground of multiple photovoltaic channels based on photovoltaic input voltage, positive or negative pole of corresponding photovoltaic channels and DC component of leakage current.

9. A computer device, characterized in that: include: A memory and a processor, wherein the memory and the processor are communicatively connected to each other, the memory stores computer instructions, and the processor executes the method for locating ground insulation impedance faults of multi-channel photovoltaic access according to any one of claims 1 to 7 by executing the computer instructions.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores computer instructions, and the computer instructions are used to enable a computer to execute the method for locating ground insulation impedance faults of multi-path photovoltaic access according to any one of claims 1 to 7.

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