CN215768944U - Photovoltaic inverter combiner box ground fault detection device and photovoltaic inverter - Google Patents
Photovoltaic inverter combiner box ground fault detection device and photovoltaic inverter Download PDFInfo
- Publication number
- CN215768944U CN215768944U CN202120674781.8U CN202120674781U CN215768944U CN 215768944 U CN215768944 U CN 215768944U CN 202120674781 U CN202120674781 U CN 202120674781U CN 215768944 U CN215768944 U CN 215768944U
- Authority
- CN
- China
- Prior art keywords
- ground fault
- inverter
- resistor
- combiner box
- current
- 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
Abstract
The utility model is suitable for the field of photovoltaic inverters, and provides a device for detecting the position of a ground fault of a junction box of a photovoltaic inverter, which comprises the inverter and a main junction box which is electrically connected with the inverter and comprises a plurality of paths of junction boxes, wherein a detection resistor is arranged between the inverter and the main junction box, and the middle of the detection resistor is grounded; a direct current load switch is arranged between the inverter and the combiner box; and the current detection device is used for detecting the branch current of the combiner box. After the ground fault occurs, closing the direct current load switch, forming a loop between the junction box of the ground fault and the detection resistor of the ground, checking the sum of the positive and negative current values of the branch circuits of the junction box one by one through a current detection device, and indicating that the branch circuit of the junction box has the ground fault if the difference value of the positive and negative current values of the branch circuit of the junction box is not zero; need not to break off the collection flow box one by one and inspect, very big reduction investigation time and investigation degree of difficulty. The utility model also provides a photovoltaic inverter, which comprises the photovoltaic inverter combiner box ground fault detection device.
Description
Technical Field
The utility model belongs to the field of photovoltaic inverters, and particularly relates to a photovoltaic inverter combiner box ground fault detection device and a photovoltaic inverter.
Background
For the existing large photovoltaic inverter, when the direct current side of the existing large photovoltaic inverter adopts a wire inlet mode of a fuse load switch, a plurality of confluence boxes are usually scattered in the whole photovoltaic area on the direct current side, and when the anode or cathode of a battery panel or the confluence box has a ground fault, the anode or the cathode of the battery panel or the confluence boxes usually need to be checked one by one, so that the workload and the working difficulty are greatly increased.
As shown in fig. 1, when the PV is in ground fault, the positive and negative poles of the dc voltage are respectively gathered together, so that there is no way to distinguish which junction box branch circuit is in ground fault, and at this time, the system has a very high voltage, and only the junction boxes can be disconnected one by one for inspection, which brings great inconvenience to field maintenance.
SUMMERY OF THE UTILITY MODEL
The embodiment of the utility model provides a device for detecting ground faults of a bus box of an inverter, and aims to solve the problems that the existing device needs to disconnect inspection bus boxes one by one to inspect the ground faults, so that inconvenience is brought to field maintenance and the inspection workload is large.
The embodiment of the utility model is realized in such a way, and provides a grounding fault detection device for a junction box of a photovoltaic inverter, which comprises an inverter and a main junction box which is electrically connected with the inverter and comprises a plurality of junction boxes, wherein a detection resistor is arranged between the inverter and the main junction box, one end of the detection resistor is connected with a positive electrode, the other end of the detection resistor is connected with a negative electrode, and the middle of the detection resistor is grounded; a direct current load switch is also arranged between the inverter and the main combiner box; and the current detection device is used for detecting the branch current of the multi-path combiner box.
Furthermore, the current detection device is a precision ammeter or a Hall current sensor arranged on a branch of the combiner box.
Furthermore, the control device is used for controlling the direct current load switch to be closed when the earth fault exists, and obtaining the current on the plurality of the bus box branches to judge the bus box branch with the earth fault.
Further, the detection resistor is located between the dc load switch and the inverter.
Still further, the detection resistor comprises a first resistor and a second resistor which are arranged in series, and the midpoint of the first resistor and the midpoint of the second resistor are arranged in a grounding mode.
Still further, the detection resistor further comprises one or more resistors connected in parallel with the first resistor and one or more resistors connected in parallel with the second resistor.
The utility model further provides a photovoltaic inverter which comprises the photovoltaic inverter combiner box ground fault detection device.
The device for detecting the grounding fault of the combiner box comprises an inverter and a main combiner box which is electrically connected with the inverter and comprises a plurality of combiner boxes, wherein a detection resistor is arranged between the inverter and the main combiner box, one end of the detection resistor is connected with a positive electrode, the other end of the detection resistor is connected with a negative electrode, and the middle of the detection resistor is grounded; a direct current load switch is also arranged between the inverter and the main combiner box; and the current detection device is used for detecting the branch current of the multi-path combiner box. After the ground fault occurs, closing the direct current load switch, forming a loop between a combiner box with the ground fault and a detection resistor which is grounded, measuring the sum of positive and negative current values of the branch circuits of the combiner box one by one through a current detection device, and indicating that the branch circuit of the combiner box has the ground fault if the difference value of the positive and negative current values of the branch circuit of the combiner box is not zero; need not to break off the collection flow box one by one and inspect, very big reduction investigation time and investigation degree of difficulty.
Drawings
FIG. 1 is a schematic circuit diagram of a prior art inverter DC input branch load switch;
FIG. 2 is a schematic circuit diagram according to embodiment 1 of the present invention;
fig. 3 is a schematic circuit configuration diagram according to embodiment 2 of the present invention.
Description of the reference numerals
10. A current detection device; 11. a Hall current sensor; 20. detecting a resistance; 30. a main combiner box; 40. an inverter; 50. a DC load switch; 60. and a control device.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the utility model and are not intended to limit the utility model.
The utility model provides a photovoltaic inverter combiner box ground fault detection device which comprises an inverter 40 and a main combiner box 30 which is electrically connected with the inverter 40 and comprises a plurality of combiner boxes, wherein a detection resistor 20 is arranged between the inverter 40 and the main combiner box 30, one end of the detection resistor 20 is connected with a positive electrode, the other end of the detection resistor 20 is connected with a negative electrode, and the middle of the detection resistor 20 is grounded; a direct current load switch 50 is also arranged between the inverter 40 and the header tank 30; and a current detection device 10 for detecting the branch current of the multi-way combiner box. After the ground fault occurs, the dc load switch 50 is closed, a loop is formed between the ground fault header box branch and the grounded detection resistor 20, the sum of the positive and negative current values of the header box branch is measured one by the current detection device 10, and the difference between the positive and negative current values of which header box branch is not zero indicates that the header box branch has the ground fault. Compared with the existing scheme that the combiner box is required to be disconnected one by one for inspection, the combiner box is not required to be disconnected one by one, and the inspection time and the inspection difficulty are greatly reduced.
Example one
As shown in fig. 2, the present embodiment provides a ground fault detection device for a junction box of a photovoltaic inverter, which includes an inverter 40 and a main junction box 30 electrically connected to the inverter 40 and including multiple junction boxes, wherein a detection resistor 20 is disposed between the inverter 40 and the main junction box 30, one end of the detection resistor 20 is connected to a positive electrode, the other end is connected to a negative electrode, and the middle of the detection resistor 20 is grounded; a direct current load switch 50 is also arranged between the inverter 40 and the header tank 30; and a current detection device 10 for detecting the branch current of the multi-way combiner box.
In the embodiment, PV +. 1-PV-. 11 are the positive and negative poles of the DC input of the inverter. The direct current input of the inverter comprises all branch circuits of the combiner boxes, all branch circuit currents can be measured at the direct current input port of the inverter, and the measurement of each combiner box is not needed. A plurality of combiner boxes are integrated in the main combiner box 30, and each combiner box comprises a positive pole branch and a negative pole branch. The detection resistor 20 is provided between the inverter 40 and the positive and negative bus bars of the header tank 30.
Further, the detection resistor 20 is located behind the inverter dc load switch 50. One end of the detection resistor 20 is connected to the positive electrode, and the other end of the detection resistor 20 is connected to the negative electrode. Because the fault point is at the front end of the inverter, which is a good cable and is not well wired, the detection resistor 20 can only be placed inside the inverter.
In the present embodiment, the current detection device 10 is a precision ammeter or a current clamp meter, and when a ground fault occurs, the system is still charged, and at this time, the dc load switch 50 is turned off, and the inverter bus capacitor is discharged to a safe voltage or less, and then fault detection is performed. When a wiring fault occurs, a loop is formed between the branch of the faulty combiner box and the ground detection resistor 20. At this time, the current in the other branch circuits of the combiner box flows into the branch circuit of the combiner box with the ground fault, and therefore, the difference value of the sum of the positive and negative current flowing into the branch circuit of the combiner box with the ground fault is not zero. Wherein, the differential current is determined by the bus voltage and the detection resistance. Specifically, the dc load current switch 50 is first closed, the sum of the positive electrode inflow current values and the sum of the negative electrode inflow current values of the combiner box branches are measured one by using a precision ammeter, and the difference between the positive electrode inflow current values and the negative electrode inflow current values of which combiner box branch is not zero indicates that the combiner box branch has a ground fault.
For example, when any one path of the combiner box has a ground fault, the sum of the positive current value and the negative current value of each branch is measured by using a current clamp meter, theoretically, the difference value of the branch current with the ground fault is larger, and the difference value without the ground fault is zero. If the PV1+.1 is grounded, when the DC load switch DC-LBS is turned on, the DC input voltage will form a current loop through the sensing resistor 20. At the moment, the current values of PV +.1 and PV-.1 are measured by using a current meter at the same time, the current in the PV1+.1 is negative, the current value is the sum of the currents flowing through other combiner box branches, and the corresponding PV-.1 only has the current of the branch 1; the difference value of the positive and negative current values on the PV1 branch is not zero, and the grounding fault of the combiner box on the PV1 branch can be judged at the moment.
In the detection device of this embodiment, after the ground fault occurs, the dc load switch 20 is closed, a loop is formed between the ground fault combiner box and the grounded detection resistor 20, the current detection device 10 checks the current of the combiner box branch one by one, and if the difference between the positive and negative current values of which combiner box branch is not zero, it indicates that the combiner box branch has the ground fault. Compared with the existing scheme that the combiner box is required to be disconnected one by one for inspection, the combiner box is not required to be disconnected one by one in the embodiment, and the inspection time and the inspection difficulty are greatly reduced.
Example two
On the basis of the first embodiment, the present embodiment provides a ground fault detection device for a photovoltaic inverter combiner box, further including a control device 60, where the control device 60 is connected to the dc load switch 50 and the detection resistor 20, and is used to control to close the dc load switch 50 when a ground fault occurs, and obtain currents on multiple combiner box branches to determine a combiner box branch with a ground fault.
In the present embodiment, a current detection device 10 is disposed on each of the branch circuits of the combiner box, wherein the current detection device 10 is a hall current sensor 11. When a ground fault occurs, the dc load switch 50 is first turned off, the bus voltage is dropped below the safe voltage, and then the detection is started. And (3) closing the direct current load switch 50, closing the switch of the control device 60 and obtaining the sampling value of the Hall current on each combiner box branch, wherein if one combiner box branch has a ground fault, the sum difference value of the positive pole inflow current value and the negative pole inflow current value of the branch is not zero, and the combiner box branch with the ground fault can be accurately positioned at the moment.
As shown in fig. 3, when a ground fault occurs in a certain trunk, such as PV1+.1, which is grounded, the dc load switch 50 is closed, the switches KM1 and KM2 of the control device 60 are closed, the control device 60 obtains hall current sampling values on each trunk branch, if a certain trunk is grounded, the difference between the sum of the positive pole inflow current value and the negative pole inflow current value of the branch is not zero, the trunk is determined to have a ground fault, and thus the position of the trunk with the ground fault can be accurately located. In this embodiment, the difference between the positive and negative inflow current values of the PV1+.1 branch is not zero, and then the PV1+.1 is grounded.
The detection device of the embodiment can automatically acquire the hall current sampling value of each combiner box branch when the ground fault occurs through the control device 60, the combiner box branch with the difference value of the positive electrode inflow current value and the negative electrode inflow current value being not zero is the combiner box branch with the ground fault, and the combiner box branch with the ground fault can be conveniently and accurately positioned.
EXAMPLE III
On the basis of the first or second embodiment, the present embodiment provides a ground fault detection device for a junction box of a photovoltaic inverter, and the detection resistor 20 includes a first resistor R1 and a second resistor R2 which are arranged in series.
In the present embodiment, the first resistor R1 and the second resistor R2 are provided in series between the inverter 40 and the positive and negative busbars of the header tank 30. The middle point of the first resistor R1 and the second resistor R2 is grounded so as to detect the current on the positive and negative branches of each junction box. It can be understood that the resistances of the first resistor R1 and the second resistor R2 are selected according to actual needs.
As shown in fig. 2, when any one of the combiner box ground faults occurs, a loop is formed between the faulted combiner box branch and R2. And the direct current voltage on the other branch circuit forms a current loop through the direct current input fuse (F2, F3 … F11), the F1 and the grounding point and the R2, and only a small current flows on the R1, which depends on the voltage on the equivalent resistor of the grounding fault. That is, the currents in the other branch circuits of the combiner box flow into the branch circuit of the combiner box with the ground fault, and therefore, the sum of the positive and negative current values in the branch circuit of the combiner box with the ground fault is not zero.
At this time, the sum of the positive and negative current values of each branch is measured by using a current clamp meter, and theoretically, the current difference value of the branch with the ground fault is not zero, and the difference value without the ground fault is zero. Wherein the differential current is related to the bus voltage and the magnitude of the first resistor R1 and the second resistor R2. If the PV1+.1 is grounded, when the DC load switch DC-LBS is turned on, the DC input voltage will form a current loop through the first resistor R1 and the second resistor R2. At the moment, the current values of PV +.1 and PV-.1 are measured by using a current meter at the same time, the current in the PV1+.1 is negative, the current value is the sum of the currents flowing through other combiner box branches, and the corresponding PV-.1 only has the current of the branch 1; the difference value of the positive and negative current values on the PV1 branch is not zero, and the grounding fault of the combiner box on the PV1 branch can be judged at the moment. Further, in other embodiments, the sensing resistor 20 further includes one or more resistors connected in parallel with the first resistor R1 and one or more resistors connected in parallel with the second resistor R2.
In an embodiment, there is at least one resistor in parallel with the first resistor R1 and at least one resistor in parallel with the second resistor R2. The number of resistors may be determined by the voltage and power that satisfy the application conditions.
In the detection device of the embodiment, the first resistor R1 and the second resistor R2 are arranged in series between the inverter 40 and the positive and negative busbars of the total junction box 30 so as to detect the current on the positive and negative branches of the junction box, the midpoint of the first resistor R1 and the second resistor R2 is grounded, and a loop is formed between the junction box with the ground fault and the grounded detection resistor 20, so that the position of the ground fault on the positive and negative branches of the junction box is further judged. In addition, the resistance values of the first resistor R1 and the second resistor R2 are selected according to application conditions, or the voltage and the power under the application conditions are met through the number of resistors which are respectively connected in parallel with the first resistor R1 and the second resistor R2, so that fault position detection is facilitated.
Example four
The embodiment also provides a photovoltaic inverter, which comprises the photovoltaic inverter combiner box ground fault detection device in any one of the above embodiments. The structure of the detection device is as described above, and is not described in detail herein.
After the ground fault occurs in the photovoltaic inverter of the embodiment, the dc load switch 20 is closed, a loop is formed between the ground fault combiner box and the grounded detection resistor 20, the current detection device 10 is used to check the current of the combiner box branch one by one, and the difference between the positive inflow current value and the negative inflow current value of which combiner box branch is not zero indicates that the combiner box branch has the ground fault. Compared with the existing scheme that the combiner box is required to be disconnected one by one for inspection, the photovoltaic inverter of the embodiment does not need to be disconnected one by one, and the inspection time and the inspection difficulty are greatly reduced.
According to the photovoltaic inverter combiner box ground fault detection device and the photovoltaic inverter, after a ground fault occurs, the direct current load switch 50 is closed, a loop is formed between the combiner box with the ground fault and the grounded detection resistor 20, the current detection device is used for checking the current of the combiner box branch one by one, and the difference value of the sum of the positive electrode inflow current value and the negative electrode inflow current value of which combiner box branch is not zero indicates that the combiner box branch has the ground fault; compared with the existing scheme that the combiner boxes need to be disconnected one by one for inspection, the combiner box inspection method and the device do not need to disconnect the combiner boxes one by one, and greatly reduce inspection time and inspection difficulty. In addition, the control device 60 can automatically obtain the hall current sampling values of all the combiner box branches when the ground fault occurs, the branch with the difference value of the positive electrode inflow current value and the negative electrode inflow current value being not zero is the combiner box branch with the ground fault, and the branch with the ground fault can be conveniently and accurately positioned. Furthermore, a first resistor R1 and a second resistor R2 are serially connected between the inverter 40 and the positive and negative busbars of the total junction box 30, so as to detect the current on the positive and negative branches of each junction box, thereby further judging the position of the ground fault on the positive and negative branches of the junction box. In addition, the resistance values of the first resistor R1 and the second resistor R2 are selected according to application conditions, or the voltage and the power under the application conditions are met through the number of resistors which are respectively connected in parallel with the first resistor R1 and the second resistor R2, so that fault position detection is facilitated.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the utility model, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included within the scope of the present invention.
Claims (7)
1. The utility model provides a photovoltaic inverter collection flow box ground fault detection device which characterized in that includes:
the system comprises an inverter and a main junction box which is electrically connected with the inverter and comprises a plurality of junction boxes, wherein a detection resistor is arranged between the inverter and the main junction box, one end of the detection resistor is connected with a positive electrode, and the other end of the detection resistor is connected with a negative electrode; the middle of the detection resistor is grounded; a direct-current load switch is arranged between the inverter and the main combiner box; and the current detection device is used for detecting the branch current of the multi-path combiner box.
2. The pv inverter combiner box ground fault detection apparatus of claim 1, wherein the current detection apparatus is a precision ammeter or a hall current sensor disposed on a branch of the combiner box.
3. The photovoltaic inverter combiner box ground fault detection apparatus of claim 1 or 2,
the control device is used for controlling the direct current load switch to be closed when the ground fault exists, and obtaining the current on the multiple paths of the branch circuits of the combiner box so as to judge the branch circuit of the combiner box with the ground fault.
4. The photovoltaic inverter combiner box ground fault detection device of claim 1,
the detection resistor is positioned between the direct current load switch and the inverter.
5. The photovoltaic inverter combiner box ground fault detection device of claim 1,
the detection resistor comprises a first resistor and a second resistor which are arranged in series, and the midpoint of the first resistor and the midpoint of the second resistor are grounded.
6. The photovoltaic inverter combiner box ground fault detection device of claim 5,
the detection resistor further includes one or more resistors in parallel with the first resistor and one or more resistors in parallel with the second resistor.
7. A photovoltaic inverter is characterized in that a photovoltaic power generation unit,
the device for detecting the ground fault of the photovoltaic inverter combiner box of any one of the claims 1-6.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202120674781.8U CN215768944U (en) | 2021-04-01 | 2021-04-01 | Photovoltaic inverter combiner box ground fault detection device and photovoltaic inverter |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202120674781.8U CN215768944U (en) | 2021-04-01 | 2021-04-01 | Photovoltaic inverter combiner box ground fault detection device and photovoltaic inverter |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN215768944U true CN215768944U (en) | 2022-02-08 |
Family
ID=80094558
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202120674781.8U Active CN215768944U (en) | 2021-04-01 | 2021-04-01 | Photovoltaic inverter combiner box ground fault detection device and photovoltaic inverter |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN215768944U (en) |
-
2021
- 2021-04-01 CN CN202120674781.8U patent/CN215768944U/en active Active
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN104702208B (en) | Photovoltaic array ground insulation resistance online detecting system for high-power photovoltaic inverter | |
| CN102854395B (en) | A kind of direct-current power ground insulation resistance detecting circuit and detection method thereof | |
| CN104535839B (en) | Photovoltaic grid-connected inverter insulation resistance detecting method and detecting device for implementing same | |
| CN102841284B (en) | On-line insulated monitoring method for high voltage of electromobile | |
| CN103809070B (en) | The direction earth-fault detecting method and device carried out based on three-phase current change | |
| CN101655523B (en) | Detecting circuit for insulating resistance to ground of power cells | |
| CN109696582A (en) | Insulation resistance detection circuit and its detection method | |
| CN105548719A (en) | Detection circuit and method of grounding insulation resistors | |
| CN107102236A (en) | A kind of fault line selection method for single-phase-to-ground fault based on waveform correlation analysis after failure | |
| CN103063927B (en) | The earth impedance testing circuit of photovoltaic DC-to-AC converter and method | |
| CN109188167A (en) | Ground fault detection device and method | |
| CN105842540A (en) | Method for detecting DC bus insulation resistance | |
| CN108627732A (en) | A kind of photovoltaic battery panel method for diagnosing faults based on crossover voltage detection | |
| TW201804725A (en) | Solar battery module test method | |
| CN201740840U (en) | Earth fault phase identification device in three-phase unearthed system | |
| CN103827681B (en) | Failure detector and detection method thereof | |
| CN215768944U (en) | Photovoltaic inverter combiner box ground fault detection device and photovoltaic inverter | |
| WO2016199445A1 (en) | Method and device for testing photovoltaic generation system | |
| CN109444621A (en) | A kind of high-power NPC three-level inverter power module electric current online test method | |
| CN210015191U (en) | Direct current insulation monitoring circuit, device and electronic product | |
| CN111650424A (en) | Zero-live line current anomaly monitoring method and system based on least square method | |
| CN115021324B (en) | Confluence device, photovoltaic system and fault detection method | |
| CN207853843U (en) | Photovoltaic array ground insulation impedance detection circuit, device and non-isolated photovoltaic DC-to-AC converter | |
| CN113552495B (en) | Online detection method and device for leakage of storage battery of power supply system | |
| CN213547456U (en) | Insulation impedance detection circuit converter and photovoltaic centrifuge |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| GR01 | Patent grant | ||
| GR01 | Patent grant |