CN113267734B - Grounding detection method and application device thereof - Google Patents
Grounding detection method and application device thereof Download PDFInfo
- Publication number
- CN113267734B CN113267734B CN202010092845.3A CN202010092845A CN113267734B CN 113267734 B CN113267734 B CN 113267734B CN 202010092845 A CN202010092845 A CN 202010092845A CN 113267734 B CN113267734 B CN 113267734B
- Authority
- CN
- China
- Prior art keywords
- grounding
- photovoltaic inverter
- detection
- voltage
- ground
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E10/00—Energy generation through renewable energy sources
- Y02E10/50—Photovoltaic [PV] energy
Landscapes
- Photovoltaic Devices (AREA)
- Measurement Of Resistance Or Impedance (AREA)
- Inverter Devices (AREA)
Abstract
The invention provides a grounding detection method and an application device thereof, wherein the grounding detection method is applied to a photovoltaic inverter, the method can acquire the detection voltage of a virtual zero point of the photovoltaic inverter to the ground under the condition that a switch in a grounding detection auxiliary circuit of the photovoltaic inverter is closed, the detection voltage is used as a first detection voltage, and after the first detection voltage is judged to be larger than a first preset voltage, the grounding mode of the photovoltaic inverter is judged to be IT grounding, namely, the grounding mode can be actively detected through a photovoltaic inverter body, and compared with the prior art, the method can reduce the time, labor and material resources consumed for confirming the grounding mode of the photovoltaic inverter according to the manual measurement and the site confirmation mode.
Description
Technical Field
The invention relates to the technical field of detection, in particular to a grounding detection method and an application device thereof.
Background
In the grid-connected photovoltaic power generation field, the photovoltaic inverter is usually installed in an IT grounding mode and a TN grounding mode. In the IT grounding mode and the TN grounding mode, the shell of the photovoltaic inverter adopts grounding protection; but IT ground indicates that the back-end transformer neutral (i.e., virtual zero) of the photovoltaic inverter is not grounded (or is grounded through high impedance), and TN ground indicates that the back-end transformer neutral of the photovoltaic inverter is grounded.
For the two grounding modes, the equivalent models of the photovoltaic inverter body are quite different, and the two grounding modes are accurately identified, so that the accurate grasp of system modeling is facilitated, and the analysis and judgment of problems are also facilitated particularly under the condition of some photovoltaic inverter faults. Therefore, the identification of the grounding mode is a necessary reference condition for developing the photovoltaic inverter into intelligent diagnosis.
In the prior art, a manual measurement and field confirmation mode is generally used to determine the grounding mode of the photovoltaic inverter. However, the manual measurement and the on-site confirmation consume a lot of time, manpower and material resources, and are unfavorable for intelligent diagnosis of the photovoltaic inverter.
Disclosure of Invention
In this regard, the application provides a grounding detection method and an application device thereof, and the grounding mode of the photovoltaic inverter is determined by an intelligent diagnosis mode, so as to solve the problems of consuming a great deal of time, manpower and material resources by using a manual measurement and field confirmation mode.
In order to achieve the above object, the embodiment of the present invention provides the following technical solutions:
the first aspect of the application discloses a grounding detection method, which is applied to a photovoltaic inverter, and comprises the following steps:
Acquiring a detection voltage of a virtual zero point of the photovoltaic inverter to the ground as a first detection voltage in a state that a switch in a grounding detection auxiliary circuit of the photovoltaic inverter is closed;
judging whether the first detection voltage is larger than a first preset voltage or not;
and if the first detection voltage is larger than the first preset voltage, judging that the grounding mode of the photovoltaic inverter is IT grounding.
Optionally, in the above ground detection method, after determining whether the first detection voltage is greater than a first preset voltage, the method further includes:
if the first detection voltage is not greater than the first preset voltage, under the condition that a switch in the grounding detection auxiliary circuit is opened, the detection voltage of the virtual zero point of the photovoltaic inverter to the ground is obtained again to be used as a second detection voltage;
judging whether the second detection voltage is larger than the first preset voltage or not;
if the second detection voltage is larger than the first preset voltage, judging that the grounding mode of the photovoltaic inverter is IT grounding;
and if the second detection voltage is not greater than the first preset voltage, judging that the grounding mode of the photovoltaic inverter is TN grounding.
Optionally, in the above ground detection method, after determining that the grounding mode of the photovoltaic inverter is TN ground, the method further includes:
after the photovoltaic inverter is in grid-connected operation, acquiring the detection voltage of the virtual zero point of the photovoltaic inverter to the ground as a third detection voltage under the condition that a switch in the grounding detection auxiliary circuit is disconnected again;
judging whether the third detection voltage is larger than a second preset voltage or not;
if the third detection voltage is larger than the second preset voltage, judging that the grounding mode of the photovoltaic inverter is IT grounding;
and if the third detection voltage is not greater than the second preset voltage, judging that the grounding mode of the photovoltaic inverter is TN grounding.
Optionally, in the above ground detection method, after determining whether the first detection voltage is greater than a first preset voltage, the method further includes:
if the first detection voltage is larger than the first preset voltage, marking the judgment result as 1, and then executing the step of judging that the grounding mode of the photovoltaic inverter is IT grounding according to the judgment result;
if the first detection voltage is not greater than the first preset voltage, marking the judgment result as 0, and executing the step of re-acquiring the detection voltage of the virtual zero point of the photovoltaic inverter to the ground as a second detection voltage under the condition that a switch in the grounding detection auxiliary circuit is opened;
After performing the determining whether the second detection voltage is greater than the first preset voltage, further comprising:
if the second detection voltage is greater than the first preset voltage, marking the judgment result as 1, and then executing the step of judging that the grounding mode of the photovoltaic inverter is IT grounding according to the judgment result;
and if the second detection voltage is not greater than the first preset voltage, marking the judgment result as 0, and then executing the step of judging that the grounding mode of the photovoltaic inverter is TN grounding according to the judgment result.
Optionally, in the above ground detection method, after performing the judgment whether the third detection voltage is greater than a second preset voltage, the method further includes:
if the third detection voltage is greater than the second preset voltage, marking the judgment result as 1, and then executing the step of judging that the grounding mode of the photovoltaic inverter is IT grounding according to the judgment result;
and if the third detection voltage is not greater than the second preset voltage, marking the judgment result as 0, and then executing the step of judging that the grounding mode of the photovoltaic inverter is TN grounding according to the judgment result.
A second aspect of the present application discloses a photovoltaic inverter comprising: the device comprises a main circuit, a ground detection auxiliary circuit and a controller; wherein, the liquid crystal display device comprises a liquid crystal display device,
the ground detection auxiliary circuit is connected with the main circuit;
the control end of the main circuit and the control end of the ground detection auxiliary circuit are connected with the controller;
the controller is configured to perform the ground fault detection method as disclosed in any one of the above first aspects.
Optionally, in the above photovoltaic inverter, the ground detection auxiliary circuit is disposed between a positive electrode on the dc side of the main circuit and a ground GND on the dc side; or alternatively, the process may be performed,
the grounding detection auxiliary circuit is arranged between the direct-current side negative electrode of the main circuit and the GND; still alternatively, the method may comprise,
the grounding detection auxiliary circuit is arranged between the direct-current side positive electrode of the main circuit and the grounding end AGND of the sampling circuit; still alternatively, or in addition to the above,
the ground detection auxiliary circuit is arranged between the direct-current side negative electrode of the main circuit and the AGND.
Optionally, in the photovoltaic inverter, the ground detection auxiliary circuit includes: a switch and a resistor in series with the switch.
The third aspect of the application discloses a ground detection method, comprising:
Determining whether the detection voltage of each photovoltaic inverter is an effective detection voltage according to the running state of each photovoltaic inverter; the detection voltage is a virtual zero point to ground detection voltage detected by the photovoltaic inverter before starting;
judging whether each effective detection voltage is larger than a preset voltage or not respectively; if the effective detection voltage is larger than the preset voltage, judging that the grounding mode of the corresponding photovoltaic inverter is IT grounding, otherwise, TN grounding;
and determining the grounding mode of the matrix to which the photovoltaic inverter belongs according to the grounding mode of each photovoltaic inverter, and issuing the grounding mode to each photovoltaic inverter.
Optionally, in the above ground detection method, the determining whether the detected voltage of each photovoltaic inverter is a valid detected voltage according to the operation state of each photovoltaic inverter includes:
receiving the operation state and the detection voltage of each photovoltaic inverter;
judging whether each running state is a grid-connected state or not;
if all the running states are not grid-connected states, determining that all the detection voltages are effective detection voltages;
If at least one running state is a grid-connected state, each received detection voltage before the first running state is the grid-connected state is determined to be an effective detection voltage.
Optionally, in the above ground detection method, the determining the ground mode of the matrix to which the photovoltaic inverter belongs according to the ground mode of each photovoltaic inverter includes:
respectively counting the number of the photovoltaic inverters grounded in the IT mode and the number of the photovoltaic inverters grounded in the TN mode;
judging whether the proportion of the number of the photovoltaic inverters grounded in the IT (information technology) in the total number of the photovoltaic inverters in the square matrix is larger than a preset value or not;
if the duty ratio is larger than the preset value, determining that the grounding mode of the square matrix is IT grounding;
and if the duty ratio is not greater than the preset value, determining that the grounding mode of the square matrix is TN grounding.
Optionally, in the above ground detection method, the counting the number of photovoltaic inverters grounded in the IT ground mode and the number of photovoltaic inverters grounded in the TN ground mode respectively includes:
marking the grounding mode judgment result of the photovoltaic inverter with the effective detection voltage larger than the preset voltage as 1;
Marking the judgment result of the grounding mode of the photovoltaic inverter with the effective detection voltage not larger than the preset voltage as 0;
and respectively counting the numbers of the judgment results of 1 and 0 to obtain the number of the photovoltaic inverters with the grounding mode of IT grounding and the number of the photovoltaic inverters with the grounding mode of TN grounding.
The fourth aspect of the application discloses a monitoring platform, wherein a communication end of the monitoring platform is connected with a communication end of each photovoltaic inverter in each matrix in the photovoltaic inverter system, and the monitoring platform is used for executing the grounding detection method disclosed in any one of the third aspects.
A fifth aspect of the present application discloses a photovoltaic inverter system comprising: a photovoltaic array, and at least one photovoltaic inverter connected to the photovoltaic array;
a controller is arranged in the photovoltaic inverter;
the controllers in the photovoltaic inverters are all in communication connection; and, the controller in the photovoltaic inverter as the communication host in each of the photovoltaic inverters is configured to execute the ground detection method as disclosed in any one of the above third aspects.
Based on the grounding detection method provided by the invention, the grounding detection method is applied to the photovoltaic inverter, the method can acquire the detection voltage of the virtual zero point of the photovoltaic inverter to the ground under the state that a switch in a grounding detection auxiliary circuit of the photovoltaic inverter is closed, and the virtual zero point is used as the first detection voltage, and after the first detection voltage is judged to be larger than the first preset voltage, the grounding mode of the photovoltaic inverter is judged to be IT grounding, namely the grounding mode can be actively detected through the photovoltaic inverter body, and compared with the mode of manually measuring and confirming on site in the prior art, the method can reduce the time, labor and material resources consumed for confirming the grounding mode of the photovoltaic inverter.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings that are required to be used in the embodiments or the description of the prior art will be briefly described below, and it is obvious that the drawings in the following description are only embodiments of the present invention, and that other drawings can be obtained according to the provided drawings without inventive effort for a person skilled in the art.
FIG. 1 is a schematic diagram of equivalent impedance inside a photovoltaic inverter of a floating sampling system according to the prior art;
fig. 2 is a schematic structural diagram of a grounding auxiliary detection circuit of a photovoltaic inverter according to an embodiment of the present application;
fig. 3 to 6 are four flowcharts of a ground detection method according to an embodiment of the present application;
fig. 7 to 8 are two flowcharts of another ground detection method according to an embodiment of the present application;
fig. 9 is a flowchart for determining a matrix to which a photovoltaic inverter belongs according to an embodiment of the present application.
Detailed Description
The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
Firstly, the prior art method for identifying the grounding mode of the photovoltaic inverter in the floating sampling system is described, and the schematic diagram of the equivalent impedance inside the photovoltaic inverter in the floating sampling system can be seen in fig. 1. According to the photovoltaic inverter, under a floating ground sampling system, the obtained voltage of the virtual zero point N of the photovoltaic inverter to the ground GND is influenced by the impedance (resistance R1 and resistance R2) of the photovoltaic group string to the ground and the equivalent sampling resistance (resistance R3 and resistance R4), so that the grounding mode of the photovoltaic inverter cannot be judged normally through the obtained voltage of the virtual zero point N to the ground GND, IT grounding is easily recognized as TN grounding, and the accuracy of the grounding mode recognition of the photovoltaic inverter cannot be ensured.
In this regard, the embodiment of the application provides a photovoltaic inverter to solve the voltage of virtual zero point N to ground GND that current photovoltaic inverter obtained receives photovoltaic group string to ground impedance and self equivalent sampling resistance influence greatly, can't accurately discern self ground mode, and under floating ground sampling system, easily discern IT ground as TN ground, and the problem that ground mode discernment rate of accuracy is low.
The photovoltaic inverter mainly comprises: a main circuit, a ground detection auxiliary circuit (101 in fig. 2), and a controller.
The ground detection auxiliary circuit is connected with the main circuit.
The control end of the main circuit and the control end of the ground detection auxiliary circuit are connected with the controller.
In practical applications, the ground detection auxiliary circuit may be disposed at a specific position in the photovoltaic inverter, in addition to the case of fig. 2 showing the arrangement between the dc side positive electrode pv+ and the ground terminal GND of the dc side of the main circuit, the ground detection auxiliary circuit may be disposed between the dc side negative electrode PV-and GND of the main circuit, or between the dc side positive electrode pv+ of the main circuit and the ground terminal AGND of the sampling circuit, or between the dc side negative electrode PV-and AGND of the main circuit; that is, in the equivalent circuit shown in fig. 2, the ground detection auxiliary circuit 101 may be connected in parallel with the resistor R1, the resistor R2, or the equivalent sampling resistor R3 or R4. The specific setting position of the grounding detection auxiliary circuit is not particularly limited according to the specific application environment and the user requirement, and any setting mode is selected.
Specifically, referring also to fig. 2, the ground detection auxiliary circuit 101 includes: a switch K1, and a resistor R7 connected in series with the switch K1.
Note that, the resistors R1 and R2 in fig. 2 are resistances to ground impedance of the photovoltaic inverter; one end of the resistor R1 is connected with the positive pole PV+ of the direct current side of the main circuit, one end of the resistor R2 is connected with the negative pole PV-of the direct current side of the main circuit, the other end of the resistor R1 is connected with the other end of the resistor R2, and the connection point is grounded (namely the grounding end GND of the direct current side). The resistor R3 and the resistor R4 in the graph 2 are equivalent resistors in the photovoltaic inverter, which are used for collecting the PV voltage between the positive pole PV+ and the negative pole PV-of the photovoltaic inverter; one end of a resistor R3 is connected with a direct current side positive electrode PV+ of the main circuit, and one end of a resistor R4 is connected with a direct current side negative electrode PV-of the main circuit; the other end of the resistor R3 is connected with the other end of the resistor R4, the connection point is used as the grounding end AGND of the sampling circuit and is grounded GND through the resistor R5, and the grounding end AGND of the sampling circuit is also connected with the virtual zero point N of the photovoltaic inverter through the resistor R6.
After the photovoltaic inverter is provided with the grounding detection auxiliary circuit 101, the on-off state of the switch K1 can be controlled by the controller, the detection voltage of the virtual zero point N of the photovoltaic inverter to the ground GND of the switch K1 in the closed state and in the open state is obtained, the influence of the obtained detection voltage on the ground impedance resistors R1 and R2 and the equivalent sampling resistors R3 and R4 in the photovoltaic inverter is avoided, the grounding mode of the photovoltaic inverter can be judged normally through the obtained voltage of the virtual zero point N to the ground GND, the fact that the photovoltaic inverter is easy to recognize the IT grounding as the TN grounding can be avoided, and the grounding mode judging accuracy is improved.
In practical application, the controller in the photovoltaic inverter is used for executing the grounding detection method, and the executed grounding detection method can determine the grounding mode of the photovoltaic inverter through an intelligent diagnosis mode, so that the problems of consuming a large amount of time, manpower and material resources in a manual measurement and field confirmation mode are solved.
Specifically, referring to fig. 3, the ground detection method mainly includes the following steps:
s101, acquiring a detection voltage of a virtual zero point of the photovoltaic inverter to the ground as a first detection voltage in a state that a switch in a grounding detection auxiliary circuit of the photovoltaic inverter is closed.
In practical applications, the switch in the auxiliary circuit (i.e. switch K1 in fig. 2) can be controlled to be in a closed state by the controller in the photovoltaic inverter. And then the detection voltage of the virtual zero point of the photovoltaic inverter to the ground can be obtained in a voltage sampling mode.
The detection voltage can be obtained through a voltage sampling device arranged between a virtual zero point of the photovoltaic inverter and the ground. The sampling device can be self-contained in the photovoltaic inverter or can be additionally arranged, is not particularly limited herein, and is within the protection scope of the application.
S102, judging whether the first detection voltage is larger than a first preset voltage.
The specific value of the first preset can be determined according to the specific application environment and the user requirement, and the application is not particularly limited and belongs to the protection scope of the application. Of course, the technician obtains the value of the first preset voltage after repeated experiments or repeated practices.
If the first detection voltage is greater than the first preset voltage, step S103 is performed.
S103, judging that the grounding mode of the photovoltaic inverter is IT grounding.
In this embodiment, by the method, the detection voltage of the virtual zero point of the photovoltaic inverter to the ground can be obtained as the first detection voltage in the state that the switch in the grounding detection auxiliary circuit of the photovoltaic inverter is closed, and after the first detection voltage is determined to be greater than the first preset voltage, the grounding mode of the photovoltaic inverter is determined to be IT grounding, that is, the grounding mode can be actively detected through the photovoltaic inverter body.
Optionally, in another embodiment provided in the present application, after executing step S102 to determine whether the first detection voltage is greater than the first preset voltage, if the first detection voltage is not greater than the first preset voltage, referring to fig. 4, the ground detection method further includes the following steps:
s201, when a switch in the grounding detection auxiliary circuit is opened, the detection voltage of the virtual zero point of the photovoltaic inverter to the ground is acquired again to be used as a second detection voltage.
Specifically, the manner of acquiring the second detection voltage is the same as that of the first detection voltage, and reference may be made to step S101 described above, which is not repeated here.
S202, judging whether the second detection voltage is larger than the first preset voltage.
If the second detection voltage is greater than the first preset voltage, step S203 is executed; if it is determined that the second detection voltage is not greater than the first prediction voltage, step S204 is performed.
S203, judging that the grounding mode of the photovoltaic inverter is IT grounding.
S204, judging that the grounding mode of the photovoltaic inverter is TN grounding.
In this embodiment, after the first detection voltage is determined to be not greater than the first preset voltage, under the condition that the switch in the grounding detection auxiliary circuit is turned off, the detection voltage of the virtual zero point of the photovoltaic inverter to the ground is obtained again as the second detection voltage, and the second detection voltage is compared with the first preset voltage, so that the grounding mode of the photovoltaic inverter is determined according to the final determination result, and the accuracy of the determination of the grounding mode of the photovoltaic inverter can be improved.
In another embodiment provided by the present application, referring to fig. 5, after executing step S204 to determine that the grounding mode of the photovoltaic inverter is TN grounding, the grounding detection method further includes the following steps:
and S301, acquiring the detection voltage of the virtual zero point of the photovoltaic inverter to the ground as a third detection voltage under the condition that a switch in the grounding detection auxiliary circuit is disconnected after grid-connected operation of the photovoltaic inverter.
In practical application, the voltages of the positive electrode and the negative electrode of the direct current side of the main circuit in the photovoltaic inverter are changed after grid-connected operation of the photovoltaic inverter, and the detection voltage of the virtual zero point to the ground, which is obtained again after grid-connected operation, is changed, so that the detection voltage of the virtual zero point to the ground can be obtained again, and the grounding mode of the photovoltaic inverter is judged according to the obtained detection voltage again, so that the reliability of a judgment result is improved.
It should be noted that, the third detection voltage is obtained in the same manner as the first detection voltage, refer to step S101, and will not be described herein.
S302, judging whether the third detection voltage is larger than a second preset voltage.
If the third detection voltage is greater than the second preset voltage, step S303 is executed; if it is determined that the third detection voltage is not greater than the second detection voltage, step S304 is performed.
S303, judging that the grounding mode of the photovoltaic inverter is IT grounding.
S304, judging that the grounding mode of the photovoltaic inverter is TN grounding.
In this embodiment, after the photovoltaic inverter is grid-connected, the detection voltage of the virtual zero point to the ground can be re-acquired, and the grounding mode of the photovoltaic inverter is determined according to the re-acquired detection voltage, so that the accuracy of determining the grounding mode of the photovoltaic inverter can be further improved.
Referring to fig. 6, in another embodiment provided in the present application, after executing step S102 to determine whether the first detection voltage is greater than the first preset voltage, the ground detection method further includes:
and if the first detection voltage is greater than the first preset voltage, marking the judgment result as 1, and then executing the step of judging that the grounding mode of the photovoltaic inverter is IT grounding according to the judgment result. That is, step S501 shown in fig. 6 is performed first, flag 1=1, and then step S103 is performed.
And if the first detection voltage is not greater than the first preset voltage, marking the judgment result as 0, and executing the step of re-acquiring the detection voltage of the virtual zero point of the photovoltaic inverter to the ground as the second detection voltage under the condition that the switch in the grounding detection auxiliary circuit is opened. That is, step S502 shown in fig. 6 is performed first, flag 1=0 is set, and step S201 is performed.
After executing step S202, determining whether the second detection voltage is greater than the first preset voltage, the method further includes:
and if the second detection voltage is greater than the first preset voltage, marking the judgment result as 1, and then executing the step of judging that the grounding mode of the photovoltaic inverter is IT grounding according to the judgment result. That is, step S503 shown in fig. 6 is performed first, flag 2=1 is set, and step S203 is performed.
And if the second detection voltage is not greater than the first preset voltage, marking the judgment result as 0, and then executing the step of judging that the grounding mode of the photovoltaic inverter is TN grounding according to the judgment result. That is, step S504 shown in fig. 6 is performed first, flag 2=0 is marked, and step S204 is performed.
Referring to fig. 6, after executing step S302 to determine whether the third detection voltage is greater than the second preset voltage, the ground detection method further includes:
and if the third detection voltage is greater than the second preset voltage, marking the judgment result as 1, and then executing the step of judging that the grounding mode of the photovoltaic inverter is IT grounding according to the judgment result. That is, step S505 shown in fig. 6 is performed first, flag 3=1 is marked, and step S303 is performed.
And if the third detection voltage is not greater than the second preset voltage, marking the judgment result as 0, and then executing the step of judging that the grounding mode of the photovoltaic inverter is TN grounding according to the judgment result. That is, step S506 shown in fig. 6 is performed first, flag 3=0 is set, and step S304 is performed.
In this embodiment, after each judgment result is obtained, the judgment result is marked first, and then the subsequent steps are executed, so that the photovoltaic inverter body can determine the final grounding mode of the photovoltaic inverter according to each judgment result mark in practical application, and the accuracy of judging the butting mode of the photovoltaic inverter is further improved.
In summary, according to the grounding detection method provided by the application, the controller is used for controlling the on-off state of the switch in the grounding detection auxiliary circuit, so that the detection voltage of the virtual zero point of the photovoltaic inverter to the ground in the closed state and the open state of the switch is obtained, the influence of the obtained detection voltage on the ground impedance resistance sum and the equivalent sampling resistance sum in the photovoltaic inverter is avoided, the grounding mode of the photovoltaic inverter can be judged normally through the obtained voltage of the virtual zero point to the ground, the fact that the photovoltaic inverter is easy to recognize the IT grounding as TN grounding can be avoided, and the judgment accuracy of the grounding mode is improved.
In the actual research and development process of the project, IT grounding mode and TN grounding mode are found to influence the internal impedance of the photovoltaic inverter system, the internal impedance can influence the detection precision of the system insulation impedance, and the grounding detection method provided by the application can ensure the accuracy of the grounding mode judgment of the photovoltaic inverter, so that the influence of the error of the grounding mode judgment on the detection precision of the system insulation impedance can be reduced.
Another embodiment provided in the present application further provides a ground detection method, which may be applied to a monitoring platform or a controller of a photovoltaic inverter as a communication host, referring to fig. 7, the ground detection method mainly includes the following steps:
s601, determining whether the detection voltage of each photovoltaic inverter is an effective detection voltage according to the operation state of each photovoltaic inverter.
The detection voltage is a virtual zero point detection voltage to ground, which is obtained by detecting the photovoltaic inverter before starting.
In practical applications, it may be determined whether the detected voltage of each photovoltaic inverter is a valid detected voltage through the specific steps shown in fig. 8. Of course, it is also possible to determine whether the detected voltage of each photovoltaic inverter is a valid detected voltage by other manners in the prior art, which are all within the protection scope of the present application.
S602, judging whether each effective detection voltage is larger than a preset voltage or not.
In practical application, the specific value of the preset voltage can be determined according to the application environment and the user requirement, and the application is not particularly limited and belongs to the protection scope of the application. Of course, the preset voltage value obtained is a preferred value after repeated experiments or repeated practices by technicians.
If the effective detection voltage is larger than the preset voltage, judging that the grounding mode of the corresponding photovoltaic inverter is IT grounding; if the effective detection voltage is not greater than the preset voltage, the grounding mode of the corresponding photovoltaic inverter is determined to be TN grounding.
S603, determining the grounding mode of the matrix to which the photovoltaic inverter belongs according to the grounding mode of each photovoltaic inverter, and transmitting the grounding mode to each photovoltaic inverter.
In practical applications, according to the grounding mode of each photovoltaic inverter, the grounding mode of the matrix to which the photovoltaic inverter belongs may be specifically determined as shown in fig. 9:
s801, counting the number of the photovoltaic inverters grounded by IT and the number of the photovoltaic inverters grounded by TN respectively.
In practical application, the determination result of the grounding mode of the photovoltaic inverter with the effective detection voltage being greater than the preset voltage may be marked as 1, the determination result of the grounding mode of the photovoltaic inverter with the effective detection voltage not greater than the preset voltage may be marked as 0, and then the numbers of the determination results of 1 and 0 are counted respectively, so that the number of photovoltaic inverters with the grounding mode being IT grounding and the number of photovoltaic inverters with the grounding mode being TN grounding may be determined.
S802, judging whether the grounding mode is that the duty ratio of the number of the IT grounded photovoltaic inverters in the total number of the photovoltaic inverters in the square matrix is larger than a preset value.
The square matrix generally refers to related equipment connected into the same box-type transformer, and comprises at least one photovoltaic inverter and a photovoltaic array connected into the direct current side of the photovoltaic inverter, wherein each photovoltaic array comprises at least one photovoltaic group string, and each photovoltaic group string is formed by connecting a plurality of photovoltaic modules in series.
If IT is determined that the grounding mode is that the duty ratio of the number of the photovoltaic inverters with IT grounding in the total number of the photovoltaic inverters in the square matrix is greater than the preset value, step S803 is executed; if IT is determined that the grounding mode is that the duty ratio of the number of IT-grounded photovoltaic inverters in the total number of photovoltaic inverters in the square matrix is not greater than the preset value, step S804 is executed.
S803, determining that the grounding mode of the square matrix is IT grounding.
S804, determining that the grounding mode of the square matrix is TN grounding.
In this embodiment, through the above principle, the monitoring platform or the controller can obtain the grounding mode of each photovoltaic inverter according to the virtual zero point to ground effective detection voltage obtained by detecting each photovoltaic inverter before starting up, and finally determine the grounding mode of the matrix to which the photovoltaic inverter belongs, and send the grounding mode to each photovoltaic inverter, that is, the monitoring platform or the controller can monitor online in real time to determine the grounding mode of the matrix to which each photovoltaic inverter belongs. And after the grounding modes of the photovoltaic inverters corresponding to the square matrix are comprehensively analyzed through the monitoring platform, the grounding mode of the square matrix of the photovoltaic inverter is obtained, and the accuracy rate of identifying the grounding modes can be greatly improved.
It should be noted that, compared with the aforementioned grounding detection method applied to the photovoltaic inverter, when the grounding detection method provided by the embodiment is applied to the monitoring platform, the grounding detection is not performed on the photovoltaic inverter body, and the grounding mode obtained by the photovoltaic inverter is obtained after the grounding mode is communicated with the monitoring platform in real time.
Optionally, in another embodiment provided in the present application, step S601 is executed to determine, according to the operation state of each photovoltaic inverter, whether the detected voltage of each photovoltaic inverter is a valid detected voltage, referring to fig. 8, including the following steps:
s701, receiving an operation state and a detection voltage of each photovoltaic inverter.
In practical application, the time of the monitoring platform for receiving the running state and the detection voltage uploaded by each photovoltaic inverter depends on the uploading time of each photovoltaic inverter, and the running state and the detection voltage can be identical, not identical or not identical, not specifically limited, and are all within the protection scope of the application.
S702, judging whether each operation state is a grid-connected state.
If each running state is not the grid-connected state, executing step S703; if at least one of the operation states is a grid-connected state, step S704 is performed.
S703, determining the detection voltage as a valid detection voltage.
S704, determining that each detection voltage received before the first running state is the grid-connected state is the effective detection voltage.
In this embodiment, the monitoring platform can combine the grid-connected condition of the photovoltaic inverters in the square matrix, synthesize the grounding mode of each photovoltaic inverter, and finally determine the grounding mode of the square matrix to which the photovoltaic inverter belongs, so as to ensure the accuracy of the judgment of the grounding mode of the photovoltaic inverter.
The following describes, with a specific example, whether each operation state is a grid-connected state or not:
when the monitoring platform executes step S702 and judges whether each operation state is a grid-connected state, each photovoltaic inverter in the square matrix can be numbered first. If the number of the photovoltaic inverters in the square matrix is 5, the 5 photovoltaic inverters can be respectively numbered A, B, C, D, E.
After sending the respective operating states and the detection voltages to the monitoring platform, the respective photovoltaic inverters:
assuming that the running states of the photovoltaic inverters with the numbers A, B, C, D, E are not grid-connected running states, the monitoring platform can determine that all the photovoltaic inverters are not in the grid-connected states according to the numbers, and consider all the detection voltages as effective detection voltages.
Assuming that the monitoring platform receives the parameters sent by each photovoltaic inverter according to the numbering sequence A, B, C, D, E, and the running state of the photovoltaic inverter with the number of C is a grid-connected state, the monitoring platform can determine that the photovoltaic inverter with the number of C is in the grid-connected state according to the corresponding number, and consider each detection voltage before the parameters of the photovoltaic inverter with the number of C are received as an effective detection voltage, that is, consider the detection voltages of the photovoltaic inverters with the numbers of a and B as effective detection voltages, and go to step S602, and discard the detection voltages of other photovoltaic inverters.
It should be noted that, the specific form of the number may be diversified, any letter or number may be adopted, and the letter is adopted for numbering, which is only one practical application form provided in the present application, and the manner of numbering in other forms is all within the protection scope of the present application.
It should be noted that, the execution body of the embodiment is only described with the monitoring platform, but in practical application, the execution body may be a controller in a photovoltaic inverter as a communication host, that is, the controller may also execute the above method, besides being the monitoring platform. Specifically, the steps of the detection method executed by the controller are not different from the above, and are not repeated here, and all belong to the protection scope of the application.
The other embodiment of the application also provides a monitoring platform, wherein the communication end of the monitoring platform is connected with the communication end of each photovoltaic inverter in each square matrix in the photovoltaic inverter system, and the photovoltaic inverter system realizes the centralized control of each photovoltaic inverter through the monitoring platform; the monitoring platform is used for executing the grounding detection method disclosed in any embodiment.
In practical application, the monitoring platform can be an independent monitoring platform and can be integrated in any photovoltaic inverter. Of course, the specific form of the monitoring platform can be determined according to the application environment and the user requirement, and the application is not particularly limited and belongs to the protection scope of the application. Moreover, the specific number of the monitoring platforms connected with the photovoltaic inverter can be determined according to the specific application environment, and the monitoring platforms are not specifically limited and belong to the protection scope of the application.
It should be noted that, the ground detection method executed by the monitoring platform can refer to the embodiments corresponding to fig. 7 to 9, and will not be described herein again.
Another embodiment of the present application further provides a photovoltaic inverter system, including: a photovoltaic array, and at least one photovoltaic inverter connected to the photovoltaic array.
The photovoltaic inverter is internally provided with a controller.
The controllers in the photovoltaic inverters are all in communication connection and adopt master-slave control; and, the controller in the photovoltaic inverter as the communication host among the respective photovoltaic inverters is used to execute the ground detection method as disclosed in any one of the above embodiments.
It should be noted that, the ground detection method executed by the controller can refer to the corresponding embodiments of fig. 7 to 9, and will not be described herein again.
In this specification, each embodiment is described in a progressive manner, and identical and similar parts of each embodiment are all referred to each other, and each embodiment mainly describes differences from other embodiments. In particular, for a system or system embodiment, since it is substantially similar to a method embodiment, the description is relatively simple, with reference to the description of the method embodiment being made in part. The systems and system embodiments described above are merely illustrative, wherein the elements illustrated as separate elements may or may not be physically separate, and the elements shown as elements may or may not be physical elements, may be located in one place, or may be distributed over a plurality of network elements. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of this embodiment. Those of ordinary skill in the art will understand and implement the present invention without undue burden.
Those of skill would further appreciate that the various illustrative elements and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware, computer software, or combinations of both, and that the various illustrative elements and steps are described above generally in terms of functionality in order to clearly illustrate the interchangeability of hardware and software. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the solution. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present invention.
The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
It is further noted that relational terms such as first and second, and the like are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Moreover, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one … …" does not exclude the presence of other like elements in a process, method, article, or apparatus that comprises the element.
Claims (14)
1. The utility model provides a ground detection method, characterized by is applied to photovoltaic inverter, the ground detection auxiliary circuit of photovoltaic inverter is connected with the main circuit of photovoltaic inverter, and the control end of main circuit with the control end of ground detection auxiliary circuit all links to each other with the controller, ground detection auxiliary circuit includes the switch and with the resistance of switch series connection, ground detection method includes:
Acquiring a detection voltage of a virtual zero point of the photovoltaic inverter to the ground as a first detection voltage in a state that a switch in a grounding detection auxiliary circuit of the photovoltaic inverter is closed;
judging whether the first detection voltage is larger than a first preset voltage or not;
and if the first detection voltage is larger than the first preset voltage, judging that the grounding mode of the photovoltaic inverter is IT grounding.
2. The ground detection method according to claim 1, further comprising, after determining whether the first detection voltage is greater than a first preset voltage:
if the first detection voltage is not greater than the first preset voltage, under the condition that a switch in the grounding detection auxiliary circuit is opened, the detection voltage of the virtual zero point of the photovoltaic inverter to the ground is obtained again to be used as a second detection voltage;
judging whether the second detection voltage is larger than the first preset voltage or not;
if the second detection voltage is larger than the first preset voltage, judging that the grounding mode of the photovoltaic inverter is IT grounding;
and if the second detection voltage is not greater than the first preset voltage, judging that the grounding mode of the photovoltaic inverter is TN grounding.
3. The ground detection method according to claim 2, characterized by further comprising, after determining that the grounding mode of the photovoltaic inverter is TN ground:
after the photovoltaic inverter is in grid-connected operation, acquiring the detection voltage of the virtual zero point of the photovoltaic inverter to the ground as a third detection voltage under the condition that a switch in the grounding detection auxiliary circuit is disconnected again;
judging whether the third detection voltage is larger than a second preset voltage or not;
if the third detection voltage is larger than the second preset voltage, judging that the grounding mode of the photovoltaic inverter is IT grounding;
and if the third detection voltage is not greater than the second preset voltage, judging that the grounding mode of the photovoltaic inverter is TN grounding.
4. The ground detection method according to claim 2, further comprising, after determining whether the first detection voltage is greater than a first preset voltage:
if the first detection voltage is larger than the first preset voltage, marking the judgment result as 1, and then executing the step of judging that the grounding mode of the photovoltaic inverter is IT grounding according to the judgment result;
if the first detection voltage is not greater than the first preset voltage, marking the judgment result as 0, and executing the step of re-acquiring the detection voltage of the virtual zero point of the photovoltaic inverter to the ground as a second detection voltage under the condition that a switch in the grounding detection auxiliary circuit is opened;
After performing the determining whether the second detection voltage is greater than the first preset voltage, further comprising:
if the second detection voltage is greater than the first preset voltage, marking the judgment result as 1, and then executing the step of judging that the grounding mode of the photovoltaic inverter is IT grounding according to the judgment result;
and if the second detection voltage is not greater than the first preset voltage, marking the judgment result as 0, and then executing the step of judging that the grounding mode of the photovoltaic inverter is TN grounding according to the judgment result.
5. The ground detection method according to claim 3, further comprising, after performing the determination as to whether the third detection voltage is greater than a second preset voltage:
if the third detection voltage is greater than the second preset voltage, marking the judgment result as 1, and then executing the step of judging that the grounding mode of the photovoltaic inverter is IT grounding according to the judgment result;
and if the third detection voltage is not greater than the second preset voltage, marking the judgment result as 0, and then executing the step of judging that the grounding mode of the photovoltaic inverter is TN grounding according to the judgment result.
6. A photovoltaic inverter, comprising: the device comprises a main circuit, a ground detection auxiliary circuit and a controller; wherein, the liquid crystal display device comprises a liquid crystal display device,
the ground detection auxiliary circuit is connected with the main circuit;
the control end of the main circuit and the control end of the ground detection auxiliary circuit are connected with the controller;
the controller is configured to perform the ground fault detection method of any one of claims 1-5.
7. The photovoltaic inverter of claim 6, wherein the ground detection auxiliary circuit is disposed between a dc side positive electrode of the main circuit and a ground GND on the dc side; or alternatively, the process may be performed,
the grounding detection auxiliary circuit is arranged between the direct-current side negative electrode of the main circuit and the GND; still alternatively, the method may comprise,
the grounding detection auxiliary circuit is arranged between the direct-current side positive electrode of the main circuit and the grounding end AGND of the sampling circuit; still alternatively, or in addition to the above,
the ground detection auxiliary circuit is arranged between the direct-current side negative electrode of the main circuit and the AGND.
8. The photovoltaic inverter of claim 7 wherein the ground detection auxiliary circuit comprises: a switch and a resistor in series with the switch.
9. A ground detection method, comprising:
Determining whether the detection voltage of each photovoltaic inverter is an effective detection voltage according to the running state of each photovoltaic inverter; the detection voltage is a virtual zero point detection voltage to the ground, which is detected in a state that a switch in a grounding detection auxiliary circuit of the photovoltaic inverter is closed before the photovoltaic inverter is started; the photovoltaic inverter comprises a grounding detection auxiliary circuit, the grounding detection auxiliary circuit is connected with a main circuit of the photovoltaic inverter, a control end of the main circuit and a control end of the grounding detection auxiliary circuit are both connected with a controller, and the grounding detection auxiliary circuit comprises a switch and a resistor connected with the switch in series;
judging whether each effective detection voltage is larger than a preset voltage or not respectively; if the effective detection voltage is larger than the preset voltage, judging that the grounding mode of the corresponding photovoltaic inverter is IT grounding, otherwise, TN grounding;
and determining the grounding mode of the matrix to which the photovoltaic inverter belongs according to the grounding mode of each photovoltaic inverter, and issuing the grounding mode to each photovoltaic inverter.
10. The ground detection method according to claim 9, wherein the determining whether the detection voltage of each of the photovoltaic inverters is a valid detection voltage according to the operation state of each of the photovoltaic inverters includes:
Receiving the operation state and the detection voltage of each photovoltaic inverter;
judging whether each running state is a grid-connected state or not;
if all the running states are not grid-connected states, determining that all the detection voltages are effective detection voltages;
if at least one running state is a grid-connected state, each detection voltage received before the first running state is the grid-connected state is determined to be an effective detection voltage.
11. The ground detection method according to claim 9, wherein the determining the ground mode of the matrix to which the photovoltaic inverter belongs according to the ground mode of each of the photovoltaic inverters comprises:
respectively counting the number of the photovoltaic inverters grounded in the IT mode and the number of the photovoltaic inverters grounded in the TN mode;
judging whether the proportion of the number of the photovoltaic inverters grounded in the IT (information technology) in the total number of the photovoltaic inverters in the square matrix is larger than a preset value or not;
if the duty ratio is larger than the preset value, determining that the grounding mode of the square matrix is IT grounding;
and if the duty ratio is not greater than the preset value, determining that the grounding mode of the square matrix is TN grounding.
12. The ground detection method according to claim 11, wherein the counting the number of the photovoltaic inverters grounded in the IT and the number of the photovoltaic inverters grounded in the TN respectively includes:
Marking the grounding mode judgment result of the photovoltaic inverter with the effective detection voltage larger than the preset voltage as 1;
marking the judgment result of the grounding mode of the photovoltaic inverter with the effective detection voltage not larger than the preset voltage as 0;
and respectively counting the numbers of the judgment results of 1 and 0 to obtain the number of the photovoltaic inverters with the grounding mode of IT grounding and the number of the photovoltaic inverters with the grounding mode of TN grounding.
13. A monitoring platform, wherein a communication end of the monitoring platform is connected to a communication end of each photovoltaic inverter in each matrix in a photovoltaic inverter system, and the monitoring platform is configured to perform the ground fault detection method according to any one of claims 9-12.
14. A photovoltaic inverter system, comprising: a photovoltaic array, and at least one photovoltaic inverter connected to the photovoltaic array;
a controller is arranged in the photovoltaic inverter;
the controllers in the photovoltaic inverters are all in communication connection; and, the controller in the photovoltaic inverter as a communication host in each of the photovoltaic inverters is configured to execute the ground detection method according to any one of claims 9 to 12.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010092845.3A CN113267734B (en) | 2020-02-14 | 2020-02-14 | Grounding detection method and application device thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010092845.3A CN113267734B (en) | 2020-02-14 | 2020-02-14 | Grounding detection method and application device thereof |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN113267734A CN113267734A (en) | 2021-08-17 |
| CN113267734B true CN113267734B (en) | 2023-05-30 |
Family
ID=77227348
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202010092845.3A Active CN113267734B (en) | 2020-02-14 | 2020-02-14 | Grounding detection method and application device thereof |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN113267734B (en) |
Family Cites Families (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101055989A (en) * | 2007-03-09 | 2007-10-17 | 张云一 | Virtual grounding power transmission and distribution system |
| JP5606387B2 (en) * | 2011-05-06 | 2014-10-15 | 山洋電気株式会社 | Motor control apparatus and motor insulation deterioration detection method |
| DE102012101340B4 (en) * | 2012-02-20 | 2015-11-19 | Sma Solar Technology Ag | Protection of photovoltaic modules of a photovoltaic generator against overvoltages to earth |
| CN105720602B (en) * | 2016-01-21 | 2019-02-05 | 易事特集团股份有限公司 | Parallel network power generation energy storage inverter is grid-connected-off-grid system and its running gear |
| CN106597103B (en) * | 2016-12-23 | 2020-05-22 | 阳光电源股份有限公司 | Photovoltaic inverter direct current side insulation resistance detection method and controller |
| CN209963765U (en) * | 2019-04-26 | 2020-01-17 | 深圳市禾望科技有限公司 | Photovoltaic grid-connected inverter |
| CN209963748U (en) * | 2019-04-26 | 2020-01-17 | 深圳市禾望科技有限公司 | Photovoltaic grid-connected inverter |
-
2020
- 2020-02-14 CN CN202010092845.3A patent/CN113267734B/en active Active
Also Published As
| Publication number | Publication date |
|---|---|
| CN113267734A (en) | 2021-08-17 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN105785175B (en) | A kind of alternating current-direct current charging pile portable detector and method | |
| Li et al. | A physics-based fractional order model and state of energy estimation for lithium ion batteries. Part II: Parameter identification and state of energy estimation for LiFePO4 battery | |
| CN104134999B (en) | Distribution network based on multi-data source measures the practical method of calculation of efficiency analysis | |
| CN101135662B (en) | Electric potential analyse electric pole measuring method and apparatus | |
| CN108548968A (en) | The performance testing device and test method of battery management system | |
| CN108445402A (en) | A kind of lithium-ion-power cell state-of-charge method of estimation and system | |
| EP1408384B1 (en) | An arrangement for controlling operation of a physical system, like for instance fuel cells in electric vehicles | |
| CN106707221B (en) | Sensor fault diagnosis method and system in a kind of electric energy metering device | |
| DE102014225374A1 (en) | Creep detection circuit with integral circuit robustness test | |
| CN106646267A (en) | Method and device for detecting service life of battery of power distribution terminal | |
| Singh et al. | Model based condition monitoring in lithium-ion batteries | |
| CN102109579B (en) | Signal monitoring system for controlling electric light source and signal monitoring method | |
| CN102654951A (en) | Automatic electronic experimental teaching system | |
| CN109975366B (en) | Rural domestic sewage A2Soft measurement method and device for COD concentration of effluent from O treatment terminal | |
| CN103983295B (en) | Sensor fault diagnosis system and diagnostic method based on signal and environmental excitation | |
| CN106789423A (en) | Interchanger automatic test device and method of testing | |
| CN104075744B (en) | A kind of remote-measuring equipment automatization calibration system | |
| CN107870283A (en) | BMS wiring testing devices and method | |
| CN113267734B (en) | Grounding detection method and application device thereof | |
| EP3719516B1 (en) | Charging device test system and method | |
| CN112083299B (en) | DC system insulation fault prediction method based on Kalman filtering | |
| CN207611129U (en) | Battery pack tests system | |
| CN113189513A (en) | Ripple-based redundant power supply current sharing state identification method | |
| CN106199318B (en) | A kind of Intelligent line inspection instrument applied to ammeter box | |
| CN116628431A (en) | Comprehensive error assessment method, system, equipment and medium for electric energy metering device |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |