阅读说明：本技术 一种光伏汇流箱及其拉弧现象处理方法 (photovoltaic combiner box and arc discharge phenomenon processing method thereof ) 是由 刘宁 陈璐 朱鸿川 李建周 刘杰斌 张天文 于 2019-10-23 设计创作，主要内容包括：本发明公开了一种光伏汇流箱,光伏汇流箱接入至少两组光伏串组,每组光伏串组分别通过一个直流断路器输出电流；电弧检测装置用于检测输出端发生拉弧现象的光伏串,且控制发生拉弧现象的所述光伏串对应的直流断路器断开。本申请中将接入的光伏串划分为至少两组光伏串组,且每组光伏串组的电流分别通过不同的直流断路器输出汇集的电流,当电弧监测模块监测到某个光伏串发生拉弧现象时,只需要通过直流断路器将接入光伏汇流箱中的部分光伏串组断开,能够保证其他光伏串组维持正常的运行,在一定程度上提高了光伏串组的工作效率。本申请还提供了一种光伏汇流箱的拉弧现象处理方法,具有上述有益效果。(The invention discloses a photovoltaic combiner box, which is connected with at least two groups of photovoltaic string groups, wherein each group of photovoltaic string groups respectively outputs current through a direct current breaker; the arc detection device is used for detecting the photovoltaic string with the arc discharge phenomenon at the output end and controlling the direct current breaker corresponding to the photovoltaic string with the arc discharge phenomenon to be disconnected. The photovoltaic string that will insert in this application divides into at least two sets of photovoltaic string groups, and the electric current of every photovoltaic string group passes through the electric current that different direct current circuit breakers output respectively and collects, when certain photovoltaic string takes place to draw the arc phenomenon is monitored to electric arc monitoring module, only need will insert the disconnection of partial photovoltaic string group in the photovoltaic conflux case through direct current circuit breaker, can guarantee that other photovoltaic string groups maintain normal operation, has improved the work efficiency of photovoltaic string group to a certain extent. The application also provides an arc discharge phenomenon processing method of the photovoltaic combiner box, and the photovoltaic combiner box has the beneficial effects.)

1. The photovoltaic combiner box is characterized in that an input port of the photovoltaic combiner box is respectively connected with at least two groups of photovoltaic string groups, and each group of photovoltaic string groups comprises a plurality of groups of photovoltaic strings; the photovoltaic combiner box comprises a plurality of fuses and a direct current breaker, wherein the first ends of the fuses are respectively connected with the positive electrode and the negative electrode of each photovoltaic string through each input port, and the input ends of the fuses are connected with the second ends of the fuses; the arc detection device is used for sensing the current change of the second end of the fuse so as to detect whether the photovoltaic string connected with the fuse generates an arc discharge phenomenon or not and is connected with the direct current circuit breaker;

The number of the direct current circuit breakers is the same as the number of the connected photovoltaic string groups, and second ends of the fuses connected with the positive and negative electrodes of the photovoltaic strings in the same photovoltaic string group are respectively connected with the positive and negative input ends of the same direct current circuit breaker in a gathering manner; the output end of each direct current breaker is connected with the output port of the photovoltaic combiner box in parallel;

The arc detection device is used for controlling the direct current circuit breaker corresponding to the photovoltaic string which generates the arc discharge phenomenon to be disconnected when the photovoltaic string which generates the arc discharge phenomenon is detected.

2. the photovoltaic combiner box of claim 1, wherein the arc detection device comprises an arc measurement and control module and an upper computer connected to the arc measurement and control module; and the upper computer is used for giving an alarm when the arc measurement and control module detects the photovoltaic string with the arc discharge phenomenon.

3. the photovoltaic combiner box of claim 2, wherein the input end of the arc measurement and control module is further configured to sense a current change at the output port of the photovoltaic combiner box, and detect whether an arc discharge occurs at the output port of the photovoltaic combiner box; when the output port of the photovoltaic combiner box generates an arc discharge phenomenon, all direct current breakers in the photovoltaic combiner box are disconnected;

the upper computer is used for sending an alarm when the arc measuring and controlling module detects that the arc discharge phenomenon occurs at the output port of the photovoltaic combiner box.

4. the photovoltaic combiner box of claim 2, further comprising a lightning protection module coupled to a second end of the fuse corresponding to the photovoltaic string, and wherein each group of the photovoltaic strings corresponds to one of the lightning protection modules; the lightning protection module comprises a first surge protector, a second surge protector and a third surge protector, wherein the input end of the first surge protector is connected with the second end of the fuse corresponding to the positive pole and the negative pole of the photovoltaic string group, the output end of the first surge protector is connected in parallel with the input end of the fuse corresponding to the negative pole of the photovoltaic string group, and the output end of the third surge protector is grounded.

5. The photovoltaic combiner box of any one of claims 2 to 4, further comprising a temperature detection device connected with the upper computer and used for detecting the temperature in the photovoltaic combiner box and sending the detection result to the upper computer.

6. The photovoltaic combiner box of claim 5, wherein the temperature sensing device is a thermistor.

7. An arc discharge phenomenon processing method of a photovoltaic combiner box, which is applied to the photovoltaic combiner box according to any one of claims 1 to 6, and comprises the following steps:

Sensing current changes of a plurality of fuses connected with each photovoltaic string in real time;

when the current change of the fuse meets a preset current change condition, determining that the arc discharge phenomenon occurs in a photovoltaic string connected with the fuse;

Controlling the direct current breaker corresponding to the photovoltaic string with the arc discharge phenomenon to be disconnected; the direct current circuit breaker corresponding to the photovoltaic string is a direct current circuit breaker connected with the photovoltaic string through a fuse.

8. The method for handling the arcing phenomenon of the photovoltaic combiner box of claim 7, wherein the photovoltaic string set accessed by the photovoltaic combiner box comprises a second photovoltaic string set and a first photovoltaic string set, wherein the probability of the arcing phenomenon of the photovoltaic string in the second photovoltaic string set is greater than the probability of the arcing phenomenon of the photovoltaic string in the first photovoltaic string set;

After controlling the corresponding direct current breaker of photovoltaic cluster disconnection, still include:

if the photovoltaic string group where the photovoltaic string is located belongs to the first photovoltaic string group, selecting and displaying the transferred photovoltaic string with the lowest probability of reoccurrence of arc discharge according to the historical arc discharge record of each photovoltaic string in the second photovoltaic string group;

The migration photovoltaic string is used for being mutually exchanged with the photovoltaic string which generates the arc discharge phenomenon at present and is connected to the position of the photovoltaic combiner box.

9. The method for processing the arcing phenomenon of the photovoltaic combiner box according to claim 7, wherein the step of selecting and displaying the transition photovoltaic string with the lowest probability of the arcing phenomenon again according to the historical arcing records of the photovoltaic strings in the second photovoltaic string group comprises the following steps:

And selecting the photovoltaic string with the longest time from the last arc discharge phenomenon to the current moment as a migration photovoltaic string according to the historical arc discharge record.

10. The method for handling the arcing phenomenon of a photovoltaic combiner box of claim 7, further comprising:

detecting the change of the confluence current of the output port of the photovoltaic confluence box in real time;

and when the change of the confluence current is larger than the preset confluence current change condition, controlling each direct current breaker to be switched off.

Technical Field

The invention relates to the technical field of solar energy, in particular to a photovoltaic combiner box and an arc discharge phenomenon processing method of the photovoltaic combiner box.

Background

Solar energy is a clean energy source for hot doors, and among them, a solar photovoltaic cell is one of important applications of solar energy. In order to reduce the connecting lines between the solar photovoltaic cell array and the inverter, a certain number of photovoltaic cells with the same specification can be connected in series to form a plurality of photovoltaic strings, then the photovoltaic strings are connected in parallel to the photovoltaic combiner box, and after the photovoltaic strings are combined with the photovoltaic combiner box, the photovoltaic strings are matched with the photovoltaic inverter to form a complete photovoltaic power generation system, so that the grid connection with commercial power is realized.

At present, along with the gradual improvement of the working efficiency of the solar cell, the voltage flowing into the same combiner box is gradually increased, so that the probability of arc discharge of each branch in the combiner box is increased to a certain extent.

in the electrical industry, when the voltage between two conductors breaks down an air layer to form an arc, the air generates a large amount of electrons after the arc is formed, the conductivity is rapidly improved, and the arc cannot be extinguished even if the distance between the two conductors is continuously increased, namely the arc is drawn. The current or voltage of a certain photovoltaic string entering the combiner box is too large, the possibility of breakdown between the current or voltage and the output branch of the adjacent photovoltaic string is greatly increased, and once an electric arc is formed between the photovoltaic strings, serious consequences such as fire disasters can be caused.

Disclosure of Invention

The invention aims to provide a photovoltaic combiner box and a method for processing an arc discharge phenomenon of the photovoltaic combiner box, which improve the utilization rate of electric energy generated by a photovoltaic assembly on the basis of ensuring the safety of the photovoltaic combiner box.

In order to solve the technical problem, the invention provides a photovoltaic combiner box, wherein an input port of the photovoltaic combiner box is respectively connected with at least two groups of photovoltaic string groups, and each group of photovoltaic string groups comprises a plurality of groups of photovoltaic strings; the photovoltaic combiner box comprises a plurality of fuses and a direct current breaker, wherein the first ends of the fuses are respectively connected with the positive electrode and the negative electrode of each photovoltaic string through each input port, and the input ends of the fuses are connected with the second ends of the fuses; the arc detection device is used for sensing the current change of the second end of the fuse so as to detect whether the photovoltaic string connected with the fuse generates an arc discharge phenomenon or not and is connected with the direct current circuit breaker;

The number of the direct current circuit breakers is the same as the number of the connected photovoltaic string groups, and second ends of the fuses connected with the positive and negative electrodes of the photovoltaic strings in the same photovoltaic string group are respectively connected with the positive and negative input ends of the same direct current circuit breaker in a gathering manner; the output end of each direct current breaker is connected with the output port of the photovoltaic combiner box in parallel;

the arc detection device is used for controlling the direct current circuit breaker corresponding to the photovoltaic string which generates the arc discharge phenomenon to be disconnected when the photovoltaic string which generates the arc discharge phenomenon is detected.

The arc detection device comprises an arc measurement and control module and an upper computer connected with the arc measurement and control module; and the upper computer is used for giving an alarm when the arc measurement and control module detects the photovoltaic string with the arc discharge phenomenon at the output end.

The input end of the arc measurement and control module is also used for sensing the current change of the output port of the photovoltaic combiner box and detecting whether the output port of the photovoltaic combiner box generates an arc discharge phenomenon; when the output port of the photovoltaic combiner box generates an arc discharge phenomenon, all direct current breakers in the photovoltaic combiner box are disconnected;

The upper computer is used for sending an alarm when the arc measuring and controlling module detects that the arc discharge phenomenon occurs at the output port of the photovoltaic combiner box.

The lightning protection device also comprises lightning protection modules connected with the second ends of the fuses corresponding to the photovoltaic strings, and each group of photovoltaic strings corresponds to one lightning protection module; the lightning protection module comprises a first surge protector, a second surge protector and a third surge protector, wherein the input end of the first surge protector is connected with the second end of the fuse corresponding to the positive pole and the negative pole of the photovoltaic string group, the output end of the fuse is connected in parallel with the input end of the third surge protector in series, and the output end of the third surge protector is grounded.

the photovoltaic junction box comprises a photovoltaic junction box body, an upper computer and a temperature detection device, wherein the temperature detection device is connected with the upper computer and used for detecting the temperature in the photovoltaic junction box and sending a detection result to the upper computer.

wherein, the temperature detection device is a thermistor.

The application also provides an arc discharge phenomenon processing method of the photovoltaic combiner box, which is applied to the photovoltaic combiner box and comprises the following steps:

Sensing the current change of a plurality of fuses connected with each photovoltaic string in real time;

When the current change of the fuse meets a preset current change condition, determining that the arc discharge phenomenon occurs in a photovoltaic string connected with the fuse;

Controlling the direct current breaker corresponding to the photovoltaic string with the arc discharge phenomenon to be disconnected; the direct current circuit breaker corresponding to the photovoltaic string is a direct current circuit breaker connected with the photovoltaic string through a fuse.

The photovoltaic string group accessed by the photovoltaic combiner box comprises a second photovoltaic string group and a first photovoltaic string group, wherein the probability of arc discharge of photovoltaic strings in the second photovoltaic string group is greater than that of the first photovoltaic string group;

After controlling the corresponding direct current breaker of photovoltaic cluster disconnection, still include:

if the photovoltaic string group where the photovoltaic string is located belongs to the first photovoltaic string group, selecting and displaying the migration photovoltaic string with the lowest probability of reoccurrence of arc discharge according to the historical arc discharge record of each photovoltaic string in the second photovoltaic string group;

the migration photovoltaic string is used for being mutually exchanged with the photovoltaic string which generates the arc discharge phenomenon at present and is connected to the position of the photovoltaic combiner box.

selecting and displaying the migration photovoltaic string with the lowest probability of reoccurring arc discharge according to the historical arc discharge record of each photovoltaic string in the second photovoltaic string group, wherein the method comprises the following steps:

and selecting the photovoltaic string with the longest time from the last arc discharge phenomenon to the current moment as a migration photovoltaic string according to the historical arc discharge record.

Wherein, still include:

Detecting the change of the confluence current of the output port of the photovoltaic confluence box in real time;

And when the change of the confluence current is larger than the preset confluence current change condition, controlling each direct current breaker to be switched off.

According to the photovoltaic combiner box provided by the invention, the input ports of the photovoltaic combiner box are respectively connected with at least two groups of photovoltaic string groups, and each group of photovoltaic string groups comprises a plurality of groups of photovoltaic strings; the photovoltaic combiner box comprises a plurality of fuses and a direct current breaker, wherein the first ends of the fuses are respectively connected with the positive electrode and the negative electrode of each photovoltaic string through each input port, and the input ends of the fuses are connected with the second ends of the fuses; the arc detection device is used for sensing the current change of the second end of the fuse so as to detect whether the photovoltaic string connected with the fuse generates an arc discharge phenomenon or not and is connected with the direct current breaker; the number of the direct current circuit breakers is the same as the number of the connected photovoltaic string groups, and the second ends of the fuses connected with the positive and negative electrodes of the photovoltaic strings in the same photovoltaic string group are respectively connected with the positive and negative input ends of the same direct current circuit breaker in a converging manner; the output end of each direct current breaker is connected with the output port of the photovoltaic combiner box in parallel; the arc detection device is used for controlling the direct current circuit breaker corresponding to the photovoltaic string with the arc discharge phenomenon to be switched off when the photovoltaic string with the arc discharge phenomenon is detected.

the photovoltaic strings connected into the photovoltaic string system are divided into at least two groups of photovoltaic string groups, and the current of each group of photovoltaic string groups is respectively output by different direct current circuit breakers to collect current, so that when an arc detection device monitors that an arc discharge phenomenon occurs to a certain photovoltaic string, the arc discharge phenomenon occurring to the photovoltaic string can be prevented from affecting other photovoltaic strings only by disconnecting the direct current circuit breaker corresponding to the photovoltaic string group to which the photovoltaic string belongs, and the other photovoltaic string groups can be ensured to maintain normal operation, so that the working efficiency of the photovoltaic string groups is improved to a certain extent.

the application also provides an arc discharge phenomenon processing method of the photovoltaic combiner box, and the photovoltaic combiner box has the beneficial effects.

drawings

in order to more clearly illustrate the embodiments or technical solutions of the present invention, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained based on these drawings without creative efforts.

Fig. 1 is a schematic diagram of an internal circuit structure of a photovoltaic combiner box according to an embodiment of the present invention;

Fig. 2 is a schematic flow chart of an arc discharge phenomenon processing method of a photovoltaic combiner box according to an embodiment of the present invention.

Detailed Description

With the gradual increase of the voltage or the current of the photovoltaic string connected into the photovoltaic combiner box, in order to avoid the arc discharge phenomenon of each branch connected into the input port of the photovoltaic combiner box, a direct current breaker and an arc detection module can be arranged in the photovoltaic combiner box. This arc detection module detects the electric current size of the branch road of every photovoltaic cluster of access respectively, in case discover this electric current sudden change and reach the threshold value, then think that this photovoltaic cluster takes place to draw the arc phenomenon, control the disconnection of direct current circuit breaker promptly for the branch road of each photovoltaic cluster of access and the output disconnection of collection flow box, and then with this collection flow box follow whole photovoltaic power supply system excision, avoid causing the influence to other collection flow boxes.

and only a few or one photovoltaic string generating arc discharge phenomenon in the photovoltaic combiner box at each time needs to be completely interrupted once the arc discharge phenomenon occurs so as to wait for the overhaul of a maintenance worker. In actual operation, the photovoltaic strings have similar fault problems such as arc discharge and the like, and workers cannot go to the maintenance immediately due to reasons such as long distance or failure to find the fault problems in time, so that all the photovoltaic strings connected with the photovoltaic header box interrupt work for a long time, and the photovoltaic strings without the arc discharge are greatly lost.

Therefore, the photovoltaic combiner box is provided, the circuit structure in the combiner box can only interrupt partial photovoltaic strings when only one or more photovoltaic strings generate an arc discharge phenomenon, and other normally working photovoltaic strings can continue to normally output current, so that the electric energy utilization rate and the working efficiency of the photovoltaic strings are improved to a certain extent.

in order that those skilled in the art will better understand the disclosure, the invention will be described in further detail with reference to the accompanying drawings and specific embodiments. It is to be understood that the described embodiments are merely exemplary of the invention, and not restrictive of the full scope of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

As shown in fig. 1, fig. 1 is a schematic diagram of an internal circuit structure of a photovoltaic combiner box according to an embodiment of the present invention, where the photovoltaic combiner box may include:

The input port of the photovoltaic combiner box is connected with at least two groups of photovoltaic string groups;

Specifically, each photovoltaic string group comprises a plurality of photovoltaic strings, and each photovoltaic string is connected in series and parallel by a plurality of photovoltaic modules together and outputs current by the same positive electrode and the negative electrode. For the photovoltaic combiner box, a plurality of input ports are provided, and the positive pole and the negative pole of each photovoltaic string are respectively connected with one input port, so that the photovoltaic strings respectively comprise PV 11-PV 1n, as shown in FIG. 1, the positive poles of the photovoltaic strings respectively comprise PV 11-PV 1n are respectively connected with the input ports PV11+ to PV1n + of the photovoltaic combiner box, and the negative poles are respectively connected with the input ports PV 11-to PV1 n-.

and, here, the photovoltaic strings accessed by each input port are divided into at least two groups, each group of photovoltaic strings is a photovoltaic string group, as shown in fig. 1, the photovoltaic strings accessed to the photovoltaic combiner box in fig. 1 are divided into two photovoltaic string groups, the first group of photovoltaic string groups is PV11 to PV1n, and the second group of photovoltaic string groups is PV21 to PV2 n. Of course, it is conceivable that fig. 1 is only a structural diagram of one embodiment provided in the present application, and all the photovoltaic strings may be divided into 3 groups, 4 groups, or even more groups in the present application, which is not limited in the present application.

The circuit structure of photovoltaic collection flow box includes: the first ends of the fuses are respectively connected with the positive electrode and the negative electrode of each photovoltaic string; a direct current breaker 2 with an input end connected with the second end of the fuse 1; and the arc detection device 3 is used for sensing the current change of the second end of each fuse 1, detecting whether the photovoltaic string connected with the fuses 1 generates arc discharge or not, and the output end of the arc detection device is connected with the direct current circuit breaker 2.

The number of the direct current circuit breakers 2 is equal to that of the photovoltaic string groups which are connected, and the positive and negative poles of each direct current circuit breaker 2 are connected with the positive and negative poles in the same photovoltaic string group; the output ends of the direct current circuit breakers 2 are connected in parallel and connected with the output port of the photovoltaic combiner box;

Specifically, as shown in fig. 1, the second ends of the fuses 1 connected to the anodes of the respective photovoltaic strings in the same group of photovoltaic string groups are collected in parallel and connected to the anode input end of one dc circuit breaker 2, and the second ends of the fuses 1 connected to the cathodes are collected in parallel and connected to the cathode input end of the same dc circuit breaker 2, that is, after the current of the same group of photovoltaic string groups is input through the fuses 1, the current is collected and connected to the same dc circuit breaker 2 and is output to the output port of the photovoltaic combiner box through the dc circuit breaker 2, that is, the current of the same group of photovoltaic string groups is controlled by the same dc circuit breaker 2 through the output of the photovoltaic combiner box, and the current of the photovoltaic strings in the different groups of photovoltaic string groups is controlled by different dc circuit breakers 2.

the arc detection device 3 is used for detecting the photovoltaic string with the arc discharge phenomenon at the output end and controlling the direct current circuit breaker 2 corresponding to the photovoltaic string with the arc discharge phenomenon to be switched off.

specifically, as shown in fig. 1, the arc detection device 3 respectively senses and detects the second end currents of the fuses connected to the anodes of the respective photovoltaic strings before the second ends of the respective fuses converge, specifically, the hall sensor may sense a current change, and determine whether an arc discharge phenomenon occurs in the corresponding photovoltaic string according to a result sensed by the hall sensor.

When the current suddenly increases, the arc discharge phenomenon of the photovoltaic string connected with the fuse 1 is described, the direct current circuit breaker 2 connected with the photovoltaic string through the fuse 1 can be disconnected at the moment, and other direct current circuit breakers 2 do not need to be disconnected, so that the photovoltaic strings in other photovoltaic string groups can be ensured to normally output current through the photovoltaic combiner box. For example, if the current of the second end of the fuse 1 connected with the PV1+ is found to be too large at one end, then the arc discharge phenomenon is likely to occur in the photovoltaic string PV1, and at this time, the first dc breaker 2 corresponding to the first group of photovoltaic strings is opened, and the second group of photovoltaic strings continues to work normally. That is, only half of the current output of the photovoltaic string needs to be interrupted.

Similarly, if the photovoltaic modules connected into the photovoltaic combiner box are divided into three groups, and three direct current circuit breakers 2 are configured, the arc discharge phenomenon occurs to the photovoltaic strings in one group of photovoltaic string groups, and the normal operation of one third of the photovoltaic strings is interrupted, so that the photovoltaic strings are divided into more groups, and the electric energy utilization rate of the photovoltaic strings is higher. But at the same time also requires the addition of a large number of dc breakers 2 and complicates the circuitry in the photovoltaic combiner box. Therefore, in practical applications, an appropriate number of packet groups can be selected.

Through carrying out the access in groups to the photovoltaic cluster of access in this application, and every photovoltaic cluster of group is organized through the output of different direct current circuit breaker 2 for when the arc phenomenon appears in partial photovoltaic cluster group in the photovoltaic cluster, can also guarantee the normal work of another partial normal photovoltaic cluster group, on the security of output electric energy in guaranteeing the collection flow box, improved the electric energy utilization of photovoltaic cluster and photovoltaic module's work efficiency to the at utmost.

based on the above embodiment, in another specific embodiment of the present invention, the arc detection device 3 specifically includes: the arc measurement and control module 32 and the upper computer 31 connected with the arc measurement and control module 32; the upper computer 31 is used for giving an alarm when the arc measurement and control module 32 detects the photovoltaic string with the arc discharge phenomenon at the output end.

Specifically, the arc measurement and control module 32 may specifically include a high-frequency current sensor (such as a hall sensor), a signal processing circuit and an analog-to-digital conversion circuit that modulate an output signal of the high-frequency current sensor, an arc determination circuit that determines an arc discharge phenomenon of the modulated signal, and an output circuit that outputs a determination result. The high-frequency current sensor is used for detecting the output current change of a PV string (photovoltaic string), and finally the output circuit outputs a judgment result to an upper computer after the output current is processed by the signal processing circuit, the analog-to-digital conversion circuit and the arc judgment circuit. The upper computer at one end receives that an arc discharge phenomenon occurs in a certain photovoltaic string, immediately sends an alarm to maintenance personnel, and the arc measurement and control module 32 also controls the corresponding direct current breaker to break the current output of the photovoltaic string.

In the above embodiments, the arc discharge phenomenon is avoided by detecting the output current of the photovoltaic string, but for the photovoltaic combiner box, the current or voltage at the output end of the photovoltaic combiner box is the largest in each branch of the whole combiner box, and for this reason, there is a high possibility that the arc discharge phenomenon occurs at the output end of the photovoltaic combiner box.

Therefore, in another specific embodiment of the present invention, the method may further include:

the input end of the arc measurement and control module 32 is also used for detecting the current change of the output end port of the photovoltaic combiner box so as to monitor whether the output end port of the photovoltaic combiner box generates an arc discharge phenomenon; when the output port of the photovoltaic combiner box generates an arc discharge phenomenon, all the direct current circuit breakers 2 are controlled to be switched off;

And the upper computer 31 is used for sending out an alarm when the arc discharge phenomenon occurs at the output port of the photovoltaic combiner box monitored by the arc measurement and control module.

In this embodiment, still detect the electric current of the output of photovoltaic combiner box, its principle of detection is the same with the principle of detecting the electric current of the output of photovoltaic cluster. However, the threshold for judging whether the arc discharge phenomenon occurs to the output end current of the photovoltaic combiner box is different from the judgment threshold for judging the output end current of the photovoltaic string, and the threshold can be set according to actual conditions.

Once the arc discharge phenomenon occurs at the output port of the photovoltaic combiner box, the current of the whole photovoltaic combiner box can not be output any more, so that all direct current breakers in the photovoltaic combiner box need to be completely disconnected, and the safety of the whole photovoltaic power system is ensured.

Furthermore, after each group of photovoltaic string groups are input into the photovoltaic combiner box to be collected, corresponding lightning protection modules need to be configured. As shown in fig. 1, specifically, each group of photovoltaic strings corresponds to one lightning protection module 4; the lightning protection module 4 comprises a first surge protector, a second surge protector and a third surge protector, wherein the input ends of the first surge protector and the second surge protector are respectively connected with the second ends of the fuses corresponding to the positive and negative poles of the same group of photovoltaic string groups, the output ends of the first surge protector and the second surge protector are connected in parallel into the input end of the third surge protector in series, and the output end of the third surge protector is grounded.

As shown in fig. 1, each lightning protection module 4 corresponds to one group of photovoltaic string groups, and performs lightning protection on current branches input by each group of photovoltaic string groups, so as to ensure the safety of each branch in the junction box.

based on any of the above embodiments, in another specific embodiment of the present invention, the method may further include:

The photovoltaic junction box is connected with the upper computer and used for detecting the temperature in the photovoltaic junction box and sending a detection result to the temperature detection device of the upper computer.

The temperature in the photovoltaic combiner box is also one of the important indexes of the normal work of the photovoltaic combiner box, and serious accidents such as fire disasters are easily caused due to overhigh temperature. Therefore, set up temperature-detecting device in the collection flow box inside in this embodiment, in case the high temperature can send out the warning to remind maintenance personal in time to inspect and remove the trouble.

the temperature detection device can specifically adopt a thermistor, and the power supply of the thermistor can be provided by the current output by the photovoltaic string.

The application also provides an arc discharge phenomenon processing method of the photovoltaic combiner box, which is applied to the photovoltaic combiner box and comprises the following steps:

sensing the current change of a plurality of fuses connected with each photovoltaic string in real time;

When the current change of the fuse meets a preset current change condition, determining that the arc discharge phenomenon of a photovoltaic string connected with the fuse occurs;

Controlling the direct current breaker corresponding to the photovoltaic string with the arc discharge phenomenon to be disconnected; the direct current circuit breaker corresponding to the photovoltaic string is a direct current circuit breaker connected with the photovoltaic string through a fuse.

specifically, the upper computer monitors the current of each photovoltaic string in real time, and once the output current value corresponding to a certain photovoltaic string is found to be greater than a preset current threshold value, it is described that an arc discharge phenomenon occurs in the photovoltaic string, and the direct current circuit breaker corresponding to the photovoltaic string group to which the photovoltaic string belongs can be controlled to be disconnected, the photovoltaic string group stops working, and the other photovoltaic string groups continue to output current normally. The current of all photovoltaic strings connected into the same photovoltaic combiner box is not required to be completely disconnected, and the utilization rate of the photovoltaic current and the working efficiency of the photovoltaic module are improved.

Based on any of the above embodiments, in another specific embodiment of the present invention, as shown in fig. 2, fig. 2 is a schematic flow chart of an arc discharge phenomenon processing method of a photovoltaic combiner box according to an embodiment of the present invention, where the method may include:

Step S11: and sensing the current change of a plurality of fuses connected with each photovoltaic string in real time.

step S12: and when the current change of the fuse meets the preset current change condition, controlling the direct current breaker corresponding to the photovoltaic string connected with the fuse to be disconnected.

step S13: and judging whether the photovoltaic string group where the photovoltaic string is located belongs to the first photovoltaic string group, if so, entering the step S14, and if not, entering the step S11.

Step S14: and selecting and displaying the migration photovoltaic string with the lowest probability of reoccurrence of arc discharge according to the historical arc discharge records of all the photovoltaic strings in the second photovoltaic string group.

It should be noted that, if an arc discharge phenomenon occurs to a photovoltaic string, the probability that the arc discharge phenomenon occurs again to the photovoltaic string is high. Therefore, the photovoltaic string groups can be artificially classified, the photovoltaic strings which are possibly subjected to the arc discharge phenomenon are concentrated into one group as much as possible, the photovoltaic strings which are subjected to the arc discharge phenomenon are prevented from being dispersed in each photovoltaic string group, the number of the photovoltaic string groups which interrupt the work is reduced as much as possible, and the electric energy utilization rate of the photovoltaic strings is further improved. Therefore, in the application, the photovoltaic strings with higher probability of arc discharge are concentrated in the second photovoltaic string group, and the photovoltaic strings with lower probability of arc discharge are concentrated in the first photovoltaic string group.

For example, in fig. 1, the photovoltaic string accessed from the access port in the left half portion in fig. 1 is the second photovoltaic string group, and the photovoltaic string accessed from the access port in the right half portion in fig. 1 is the low-frequency arcing photovoltaic string group. If the photovoltaic strings in the low-frequency arc-discharge photovoltaic string group are subjected to arc discharge, one transfer photovoltaic string can be selected from the second photovoltaic string group to be exchanged with the access position of the photovoltaic string, so that the photovoltaic string is moved to the second photovoltaic string group from the low-frequency arc-discharge photovoltaic string group.

certainly, it should be noted that, the access port position in the photovoltaic string access header box is changed, and the photovoltaic string needs to be repaired and completed and can be normally operated, and the upper computer can provide a migration strategy in advance for maintenance personnel according to the historical arc discharge record of the arc discharge phenomenon at each time, and the access position of the photovoltaic string is convenient to migrate after the maintenance of the maintenance personnel is completed.

Optionally, for the migration photovoltaic string with the lowest probability of the reoccurring arc discharge phenomenon, specifically, the following may be performed:

And selecting the photovoltaic string with the longest time from the last arc discharge phenomenon to the current moment as a migration photovoltaic string according to the historical arc discharge records.

For the photovoltaic strings without the over-arcing phenomenon, the time of the last arc-arcing phenomenon is infinitely far from the time of the current moment, and as long as the photovoltaic strings without the over-arcing phenomenon exist, the photovoltaic strings are preferably selected as the migration photovoltaic strings.

of course, there are various methods for determining the probability of the photovoltaic string generating the arc discharge phenomenon again in this embodiment, for example, the number of times of the arc discharge phenomenon occurring in a short time, and the like, and this application is not particularly limited.

As before, the monitoring of drawing the arc phenomenon is still carried out to photovoltaic combiner box's output current to the electric arc detection device in the photovoltaic combiner box, consequently, can also further include in this application:

Detecting the change of the confluence current of the output end of the photovoltaic confluence box in real time;

And when the change of the confluence current meets the preset confluence current change condition, controlling each direct current breaker to be switched off.

The safety of the photovoltaic combiner box is guaranteed to the greatest extent by detecting the comprehensive arc discharge phenomenon of the current inside the photovoltaic combiner box and the total current output, so that the safety of the whole photovoltaic system is improved.

The embodiments are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same or similar parts among the embodiments are referred to each other.

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 components and steps have been described above generally in terms of their functionality in order to clearly illustrate this 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 implementation. 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.