CN106936112B - Header box protective device - Google Patents
Header box protective device Download PDFInfo
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- CN106936112B CN106936112B CN201511025213.0A CN201511025213A CN106936112B CN 106936112 B CN106936112 B CN 106936112B CN 201511025213 A CN201511025213 A CN 201511025213A CN 106936112 B CN106936112 B CN 106936112B
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- header box
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- logic unit
- protective device
- box protective
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H3/00—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection
- H02H3/26—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to difference between voltages or between currents; responsive to phase angle between voltages or between currents
- H02H3/32—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to difference between voltages or between currents; responsive to phase angle between voltages or between currents involving comparison of the voltage or current values at corresponding points in different conductors of a single system, e.g. of currents in go and return conductors
- H02H3/325—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to difference between voltages or between currents; responsive to phase angle between voltages or between currents involving comparison of the voltage or current values at corresponding points in different conductors of a single system, e.g. of currents in go and return conductors involving voltage comparison
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- Photovoltaic Devices (AREA)
Abstract
The invention discloses a kind of header box protective devices, and wherein header box includes photovoltaic cable and breaker and header box protective device includes acquisition unit, logic unit and execution unit.Acquisition unit is electrically connected with photovoltaic cable, and is used to acquire the voltage signal of the photovoltaic cable；Logic unit is electrically connected to receive the voltage signal transmitted from acquisition unit with acquisition unit, then the electric signal is compared with comparison voltage, when the absolute value of the difference of the voltage signal and comparison voltage is greater than or equal to setting value, logic unit sends to execution unit and instructs；And execution unit is electrically connected and according to the instruction control breaker open operation transmitted from logic unit with logic unit.Header box protective device of the invention, breaker open operation can be effectively controlled when photovoltaic cable is directly grounded, thus a series of problems caused by solving because of photovoltaic cable ground connection.
Description
Technical field
The present invention relates to field of photovoltaic power generation, and in particular to a kind of header box protective device.
Background technique
Header box is a kind of electrical equipment applied in photovoltaic generating system, is responsible for the direct current for generating photovoltaic module
Electricity is transmitted to photovoltaic DC-to-AC converter after its primary confluence.In order to guarantee reliability, the safety of power generation, header box is equipped with anti-
The protection such as thunder, overcurrent and overload.But the photovoltaic cable and photovoltaic cable failure rate connecting with header box are highest
It is singlephase earth fault (plus earth or cathode ground connection), the voltage that such failure causes non-faulting phase increases, inside header box
Device it is breakdown in case of high pressures, to cause fire.It is existing in header box to protect not when such failure occurs
It can act, therefore this is a kind of defect in header box design.
Summary of the invention
The object of the present invention is to provide a kind of header box protective devices, to solve above-mentioned problems of the prior art.
To solve the above-mentioned problems, the present invention provides a kind of header box protective device, the header box includes photovoltaic electric
Cable and breaker, the header box protective device include acquisition unit, logic unit and execution unit；The acquisition unit with
The photovoltaic cable electrical connection, and it is used to acquire the voltage signal of the photovoltaic cable；The logic unit and the acquisition unit
Then electrical connection is compared the voltage signal with comparison voltage to receive the voltage signal transmitted from the acquisition unit
Compared with when the absolute value of the difference of the voltage signal and comparison voltage is greater than or equal to setting value, the logic unit is to the execution
Unit sends instruction；And the execution unit is electrically connected and according to the finger transmitted from the logic unit with the logic unit
It enables and controls the breaker open operation.
Preferably, the comparison voltage is equal to 1.25-2 times of the setting value.
Preferably, the logic unit includes comparator, the comparator respectively with the acquisition unit and the execution
Unit electrical connection.
Preferably, the logic unit further includes first resistor and second resistance, the first resistor and second resistance are divided
Not Tong Guo conducting wire connect with the positive and negative input terminal of the comparator, and the resistance value phase of the first resistor and the second resistance
Deng.
Preferably, the execution unit includes the first relay, first relay and the logic unit and described
Circuit breaker electric connection, to control the breaker open operation according to the instruction transmitted from the logic unit.
Preferably, the execution unit further includes the second relay, second relay and the logic unit and institute
Circuit breaker electric connection is stated, to control the breaker closing according to the instruction transmitted from the logic unit.
Preferably, the acquisition unit is arranged to carry out the voltage acquired from the photovoltaic cable decompression processing, and will
By decompression, treated that voltage value sends the logic unit to.
Preferably, the header box protective device further includes secondary power supply, the secondary power supply is single with the acquisition respectively
Member, logic unit and execution unit electrical connection are to provide electric energy for the acquisition unit, logic unit and execution unit.
Preferably, the comparison voltage is equal to the 17/41-20/41 of the open-circuit voltage of photovoltaic group string branch.
Preferably, the comparison voltage is equal to 380V-400V and the setting value is equal to 190V-320V.
Preferably, the comparison voltage is equal to 400V and the setting value is equal to 200V.
To sum up, header box protective device through the invention, open circuit can be effectively controlled when photovoltaic cable is directly grounded
Device separating brake, thus a series of problems caused by solving because of photovoltaic cable ground connection, and photovoltaic cable occurs through transition electricity in header box
When hindering ground fault, header box protective device of the invention can effectively control breaker open operation when endangering larger, and destroy
It is then failure to actuate when less, prevents from causing economic loss because of shutdown.
Detailed description of the invention
Fig. 1 is photovoltaic generating system schematic diagram；
Fig. 2 shows the photovoltaic cable ground connection in header box；
Fig. 3 is the schematic diagram of photovoltaic module；
Fig. 4 is each unit connection schematic diagram of header box protective device according to an embodiment of the invention；
Fig. 5 A-5B shows the main circuit diagram of logic unit of the invention；And
Fig. 6 is each unit connection schematic diagram of header box protective device according to another embodiment of the present invention.
Specific embodiment
Presently preferred embodiments of the present invention is described in detail below with reference to attached drawing, it is of the invention to be clearer to understand
Objects, features and advantages.It should be understood that embodiment shown in the drawings does not limit the scope of the present invention, and only it is
Illustrate the connotation of technical solution of the present invention.
Term explanation
Header box: header box main function is exactly that the input of photovoltaic array is carried out level-one confluence, for reducing photovoltaic battle array
Column are linked into the line of inverter, while providing lightning protection function, detect the operating status of photovoltaic panel, DC quantity state acquisition and disconnected
Road device state etc..
Photovoltaic DC-to-AC converter: photovoltaic DC-to-AC converter is to connect resistance capacitance by power electronic devices (MOSFET, IGBT etc.), with
The direct current that header box transmission comes is transformed into alternating current, is completed at the same time by the on-off of the mode control device of pulse width modulation
The MPPT maximum power point tracking (MPPT) of photovoltaic module guarantees functional control and anti-islanding effect etc..
Breaker: designed coupling or uncoupling means can close, the electric current of on-off and carrying normal condition；And it can be non-
Under normal operating condition, it is also able to carry out the conducting and on-off closed, in disjunction and certain time.
Photovoltaic generating system, electrical schematic diagram are shown in 1.From figure 1 it appears that is be connected with header box is photovoltaic electric
Cable and direct current cables.Photovoltaic cable is for the connection between photovoltaic module group string.Direct current cables is used for header box and photovoltaic inversion
Connection between device.
Fig. 2 shows occur the case where ground fault in the actual moving process of photovoltaic generating system.As shown in Fig. 2,
During photovoltaic plant actual motion, there is the probability highest of ground fault in photovoltaic cable certain point.
When solar irradiation is mapped to the surface of photovoltaic module, the photon with certain energy is absorbed, is produced in the inside of component
The raw electron-hole pair for being in non-equilibrium state；Under the action of P-N junction internal electric field, electronics, hole are tended to N, P knot respectively,
To be formed about the photoproduction electric field contrary with built in field in P-N junction；After photoproduction electric field neutralisation P-N junction built in field
Redundance makes the area P, N respectively with positive and negative point, then generates the photo-induced voltage that the area P is directed toward by the area N, i.e. photovoltaic group in Fig. 1
Part voltage；Then there is electric current to flow out after external load from the area P, loaded from the area N and flow into photovoltaic cell, schematic diagram is shown in Fig. 3.By
In the influence that P-N junction is zero reference point, under normal operating conditions, the amplitude of positive and negative electrode voltage is equal, is photovoltaic module voltage
Half.
In Fig. 2, when ground fault occurs for A point, the voltage of header box anode copper bar side is close to 0.Since P-N junction is not
The reference point of ground connection, the voltage of header box cathode copper bar side are the voltage of photovoltaic module.Cathode copper bar side voltage skyrockets, and can lead
Cause the device inside header box breakdown in case of high pressures, to cause fire.But breaker is furnished at this stage
The protections such as electric current, overload can not act and cut-off breaker.For this purpose, inventor has invented header box protection dress of the invention
It sets.
As shown in Figure 1, header box generally includes photovoltaic cable, header box fuse, copper bar and breaker.Wherein, light
Luff cable connects with photovoltaic group series winding, and photovoltaic group string by copper bar with breaker by being connected again after photovoltaic cable parallel connection, in photovoltaic
Header box fuse is set on cable.
Header box protective device of the invention generally includes acquisition unit, logic unit and execution unit.Acquisition unit
It is electrically connected with photovoltaic cable, to acquire the voltage value of the photovoltaic cable.Logic unit is electrically connected with acquisition unit, and receive from
Then the voltage value is compared, when the voltage value and reference voltage by the voltage value that acquisition unit transmits with reference voltage value
When the absolute value of the difference of value is greater than or equal to setting value, sends and instruct to execution unit.Execution unit is passed according to from logic unit
The instruction come controls breaker open operation, so that header box will not be damaged because photovoltaic cable is grounded.
Header box protective device of the invention is described in detail with reference to the accompanying drawing.
Embodiment 1
Fig. 4 is the header box protective device each unit connection schematic diagram according to the present embodiment.As shown in figure 4, header box is protected
Protection unit 100 includes acquisition unit 10, logic unit 20 and execution unit 30.Wherein, acquisition unit 10 is distinguished by conducting wire
It is electrically connected with the cathode 42 of the anode 41 of photovoltaic cable and photovoltaic cable.Logic unit 20 passes through conducting wire and 10 Electricity Federation of acquisition unit
It is logical.Execution unit 30 passes through 20 electrical communication of conducting wire and logic unit.
As shown in figure 4, the acquisition unit 10 of the present embodiment is electrical voltage system measuring device, VSM or DC/DC decompression can be
Element acquires the anode 41 of photovoltaic cable and the voltage U of cathode 42+And U-, and to the voltage U that acquisition comes+And U-It is depressured
Processing, in the voltage U come to acquisition+And U-After carrying out decompression processing, then voltage value passes to logic unit by treated, under
Text will be described in detail.In Fig. 4, PE indicates that zero reference point, GND represent protective grounding, and secondary power supply 50 is the confession of acquisition unit 10
Electricity.
Fig. 5 A, 5B are the main circuit diagram of logic unit.As shown in Fig. 5 A, 5B, logic unit mainly include comparator 21,
22, wherein Fig. 5 A shows the comparator 21 that connect of anode with photovoltaic cable, and Fig. 5 B is shown to be connect with the cathode of photovoltaic cable
Comparator 22.
Fig. 5 A shows comparator 21, resistance R1、R2And R3, wherein resistance R1One end by conducting wire and comparator 21 just
The connection of pole input terminal, resistance R1The other end be wired to acquisition unit 10, and receive from acquisition unit 10 by drop
Pressure treated voltage U+。R2One end connect with the negative input of comparator 21 by conducting wire, the other end passes through conducting wire reception
Comparison voltage UN.The output end of comparator 21 is electrically connected with execution unit 30, is instructed to send to execution unit.
Fig. 5 B is similar with Fig. 5 A, and it is single to the difference is that only that the electrode input end of comparator 22 is wired to acquisition
Member 10, and receive from acquisition unit 10 by decompression treated voltage U-.As shown in Figure 5 B, resistance R4One end pass through conducting wire
It is connect with the electrode input end of comparator 22, resistance R4The other end be wired to acquisition unit 10, and it is single from acquisition
Member 10 is received by decompression treated voltage U_。R5One end connect with the negative input of comparator 22 by conducting wire, it is another
End receives comparison voltage U by conducting wireN, comparison voltage UNIt is determined according to the open-circuit voltage of photovoltaic group string branch.It hereafter will be detailed
Description.The output end of comparator 22 is electrically connected with execution unit 30, is instructed to send to execution unit 30.
Logic unit 20 is used to comparison voltage U+、U-With reference voltage UNSize.Wherein, comparator 21 is used to more electric
Press U+With UNSize, comparator 22 be used to comparison voltage U-With comparison voltage UNSize.When meeting Biao Da Shi ∣ UN-U+∣≥ε
Huo ∣ UN-U-When ∣ >=ε (ε is setting value), it is possible to determine that photovoltaic cable ground connection also includes the case where that direct current cables is grounded certainly.
Execution unit 30 includes mainly relay J1, and relay J1 is electrically connected with logic unit 20 and breaker 60, when patrolling
Unit 20 is collected to when relay J1 transmission separating brake instruction, relay J1 control switch 31 is closed, to control 60 separating brake of breaker.
The photovoltaic cable of header box is grounded or direct current cables ground connection includes being directly grounded and through transition resistance eutral grounding, directly connecing
Ground refers to that photovoltaic cable is directly connected on the ground, refers to that photovoltaic cable is grounded again by a resistance through transition resistance eutral grounding,
Therefore, the voltage of the collected photovoltaic cable is 0 when photovoltaic cable is directly grounded, and photovoltaic cable when transition resistance eutral grounding through adopting
The value of the voltage collected additionally depends on the size of the resistance by resistance eutral grounding.
But found in inventor by a large amount of engineering practice, through transition resistance eutral grounding, if the warp
The resistance of transition resistance ground connection is sufficiently large, then caused by danger it is minimum, therefore, the present invention according to the actual conditions of engineering practice,
By UNIt is equal to the 17/41-20/41 that photovoltaic group passes the open-circuit voltage of branch, ε is equal to 0.4UN-
0.8UN, good effect can be obtained.For example, when the open-circuit voltage of photovoltaic group string branch is equal to 820V, UNEqual to 380V-
400V, ε are equal to 0.4UN-0.8UN.Preferably, when the open-circuit voltage of photovoltaic group string branch is equal to 820V, by UNIt is set as
ε is set 200V by 400V.
In the header box course of work, the case where being directly grounded in case of photovoltaic cable, since photovoltaic cable is direct
Ground connection, the voltage of grounding point are 0, therefore, pass through the collected U of acquisition unit+Or U-Equal to 0, at this point, logic unit Pan Duan Chu ∣
UN-U+∣ >=ε Huo ∣ UN-U-∣ >=ε, thus, logic unit sends separating brake instruction to execution unit, and logic unit receives separating brake and refers to
After order, it is closed by relay J1 control switch 31, to control breaker open operation.Therefore avoid header box because ground connection and
Cause serious consequence.
The case where in case of photovoltaic cable through transition resistance eutral grounding, at this time, such as fruit ∣ UN-U+∣ >=ε Huo ∣ UN-U-∣≥
ε, then logic unit sends separating brake instruction after logic unit receives separating brake instruction to execution unit and is controlled by relay J1
Switch 31 is closed, to control the breaker open operation of header box, causes serious consequence because of ground connection so as to avoid header box.
And if Bu Man Zu ∣ UN-U+∣ >=ε Huo ∣ UN-U-∣ >=ε can then not have to processing, because such situation not will cause big break
It is bad, to reduce loss caused by due to shutdown to the maximum extent.
Embodiment 2
Fig. 6 is each unit connection schematic diagram according to the header box protective device of the present embodiment.It is described referring to Fig. 6
The header box protective device 200 of the present embodiment.Embodiment 2 and the difference of embodiment 1 essentially consist in, execution unit 30 further include after
Electric appliance J2, relay J2 are electrically connected by conducting wire with logic unit, to receive the reclosing command of logic unit transmission, work as reception
To logic unit send reclosing command when, control breaker closing.
During header box work, in case of photovoltaic cable ground connection, thus control of the breaker in execution unit
When being disconnected under system, after people finder goes out ground fault and solves a problem with grounding at the scene, people can be passed through in embodiment 1
Breaker closing is sent reclosing command to relay J2 by logic unit in example 2, relay J2 is being received by work
Control switch 32 is closed after reclosing command, to control breaker closing.
To sum up, header box protective device through the invention, open circuit can be effectively controlled when photovoltaic cable is directly grounded
Device separating brake, thus a series of problems caused by solving because of photovoltaic cable ground connection, and photovoltaic cable occurs through transition electricity in header box
When hindering ground fault, header box protective device of the invention can effectively control breaker open operation when endangering larger, and endanger
It is then failure to actuate when less, prevents from causing economic loss because of shutdown.
Presently preferred embodiments of the present invention has already been described in detail above, it is understood that having read of the invention above-mentioned say
After awarding content, those skilled in the art can make various modifications or changes to the present invention.Such equivalent forms equally fall within this
Apply for the appended claims limited range.
Claims (10)
1. a kind of header box protective device, the header box include photovoltaic cable and breaker, which is characterized in that the header box
Protective device includes acquisition unit, logic unit and execution unit；The acquisition unit is electrically connected with the photovoltaic cable, and
For acquiring the voltage signal of the photovoltaic cable；The logic unit is electrically connected to receive and adopt from described with the acquisition unit
The positive and negative electrode voltage signal, is then compared by the positive and negative electrode voltage signal that transmits of collection unit with comparison voltage, when this just
When the absolute value of the difference of pole tension signal and comparison voltage is greater than or equal to setting value, or the cathode voltage signal is electric compared with
When the absolute value of the difference of pressure is greater than or equal to setting value, the logic unit sends to the execution unit and instructs；And it is described
Execution unit is electrically connected with the logic unit and controls the breaker open operation according to the instruction transmitted from the logic unit；
Wherein, positive and negative anodes are earth-free when the photovoltaic cable works normally；The header box protective device is for solving single-phase earthing event
Barrier.
2. header box protective device according to claim 1, which is characterized in that the comparison voltage is equal to the setting value
1.25-2 times.
3. header box protective device according to claim 1, which is characterized in that the logic unit includes comparator, institute
Comparator is stated to be electrically connected with the acquisition unit and the execution unit respectively.
4. header box protective device according to claim 3, which is characterized in that the logic unit further includes first resistor
And second resistance, the first resistor and second resistance pass through conducting wire respectively and connect with the positive and negative input terminal of the comparator, and
The resistance value of the first resistor and the second resistance is equal.
5. header box protective device according to claim 1, which is characterized in that the execution unit includes the first relay
Device, first relay be connected to the logic unit and the circuit breaker electric, and according to transmitting from the logic unit
Instruction controls the breaker open operation.
6. header box protective device according to claim 5, which is characterized in that the execution unit further includes the second relay
Device, second relay is connected to the logic unit and the circuit breaker electric, to transmit according to from the logic unit
Instruction control the breaker closing.
7. header box protective device according to claim 1, which is characterized in that the acquisition unit is arranged to from described
The voltage of photovoltaic cable acquisition carries out decompression processing, and will treated that voltage value sends the logic unit to by decompression.
8. header box protective device according to claim 1, which is characterized in that the header box protective device further includes two
Secondary source, the secondary power supply are electrically connected to adopt to be described respectively with the acquisition unit, logic unit and execution unit
Collect unit, logic unit and execution unit and electric energy is provided.
9. header box protective device according to claim 1, which is characterized in that the comparison voltage is equal to photovoltaic group string branch
The 17/41-20/41 of the open-circuit voltage on road.
10. header box protective device according to claim 1, which is characterized in that the comparison voltage is equal to 380V-
400V and the setting value are equal to 190V-320V.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201511025213.0A CN106936112B (en) | 2015-12-30 | 2015-12-30 | Header box protective device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201511025213.0A CN106936112B (en) | 2015-12-30 | 2015-12-30 | Header box protective device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN106936112A CN106936112A (en) | 2017-07-07 |
| CN106936112B true CN106936112B (en) | 2019-09-06 |
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ID=59441661
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201511025213.0A Active CN106936112B (en) | 2015-12-30 | 2015-12-30 | Header box protective device |
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Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2010246228A (en) * | 2009-04-03 | 2010-10-28 | Panasonic Corp | Fuel battery system |
| CN102931684A (en) * | 2012-11-09 | 2013-02-13 | 东华大学 | Photovoltaic alternate current and direct current intelligent distribution box |
| CN103107518A (en) * | 2012-12-24 | 2013-05-15 | 深圳创动科技有限公司 | Photovoltaic inverter and protector thereof |
| CN104993684A (en) * | 2015-06-30 | 2015-10-21 | 中国电力工程顾问集团华东电力设计院有限公司 | Soft start photovoltaic inverter and photovoltaic power generation system |
| CN205509468U (en) * | 2015-12-30 | 2016-08-24 | 中国电力工程顾问集团华东电力设计院有限公司 | Collection flow box protection device |
-
2015
- 2015-12-30 CN CN201511025213.0A patent/CN106936112B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2010246228A (en) * | 2009-04-03 | 2010-10-28 | Panasonic Corp | Fuel battery system |
| CN102931684A (en) * | 2012-11-09 | 2013-02-13 | 东华大学 | Photovoltaic alternate current and direct current intelligent distribution box |
| CN103107518A (en) * | 2012-12-24 | 2013-05-15 | 深圳创动科技有限公司 | Photovoltaic inverter and protector thereof |
| CN104993684A (en) * | 2015-06-30 | 2015-10-21 | 中国电力工程顾问集团华东电力设计院有限公司 | Soft start photovoltaic inverter and photovoltaic power generation system |
| CN205509468U (en) * | 2015-12-30 | 2016-08-24 | 中国电力工程顾问集团华东电力设计院有限公司 | Collection flow box protection device |
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| Publication number | Publication date |
|---|---|
| CN106936112A (en) | 2017-07-07 |
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