CN106936112A - Header box protection device - Google Patents
Header box protection device Download PDFInfo
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- CN106936112A CN106936112A CN201511025213.0A CN201511025213A CN106936112A CN 106936112 A CN106936112 A CN 106936112A CN 201511025213 A CN201511025213 A CN 201511025213A CN 106936112 A CN106936112 A CN 106936112A
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- Prior art keywords
- header box
- unit
- logic unit
- protection device
- box protection
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Classifications
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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 protection device, wherein header box includes photovoltaic cable and breaker, and header box protection device includes collecting unit, logic unit and execution unit.Collecting unit is electrically connected with photovoltaic cable, and for gathering the voltage signal of the photovoltaic cable；Logic unit is electrically connected with collecting unit so as to receive the voltage signal transmitted from collecting unit, then the electric signal and comparison voltage are compared, when the absolute value of the voltage signal and the difference of comparison voltage is more than or equal to setting value, logic unit sends to execution unit and instructs；And execution unit is electrically connected with logic unit and controls breaker open operation according to the instruction transmitted from logic unit.Header box protection device of the invention, breaker open operation can be effectively controlled when photovoltaic cable is directly grounded, so as to solve because of a series of problems that photovoltaic cable ground connection causes.
Description
Technical field
The present invention relates to field of photovoltaic power generation, and in particular to a kind of header box protection device.
Background technology
Header box is a kind of electrical equipment applied in photovoltaic generating system, and it is responsible for produce photovoltaic module
Direct current, after it once confluxes, is sent to photovoltaic DC-to-AC converter.In order to ensure the reliability, the peace that generate electricity
Quan Xing, header box is equipped with the protection such as lightning protection, overcurrent and overload.But, the photovoltaic being connected with header box
Cable and photovoltaic cable failure rate highest are singlephase earth fault (plus earth or negative pole are grounded),
Such failure triggers the voltage of non-faulting phase to raise, and the device inside header box is breakdown in case of high pressures,
So as to trigger fire.It is existing in header box to protect equal akinesia when such failure occurs, therefore this is
A class defect in header box design.
The content of the invention
It is an object of the invention to provide a kind of header box protection device, to solve present in above-mentioned prior art
Problem.
In order to solve the above problems, the invention provides a kind of header box protection device, the header box includes
Photovoltaic cable and breaker, the header box protection device include collecting unit, logic unit and perform list
Unit；The collecting unit is electrically connected with the photovoltaic cable, and for gathering the voltage signal of the photovoltaic cable；
The logic unit is electrically connected with the collecting unit so as to receive the voltage letter transmitted from the collecting unit
Number, then the voltage signal and comparison voltage are compared, when the voltage signal and the difference of comparison voltage
The logic unit sends to the execution unit and instructs when absolute value is more than or equal to setting value；And it is described
Execution unit is electrically connected and according to the instruction control transmitted from the logic unit with the logic unit
Breaker open operation.
It is preferred that the comparison voltage is equal to 1.25-2 times of the setting value.
It is preferred that the logic unit include comparator, the comparator respectively with the collecting unit and institute
State execution unit electrical connection.
It is preferred that the logic unit also includes first resistor and second resistance, the first resistor and second
Resistance is connected by wire with the positive and negative input of the comparator respectively, and the first resistor and described
The resistance of second resistance is equal.
It is preferred that the execution unit includes the first relay, first relay and the logic unit
Connected with the circuit breaker electric, so as to control the breaker point according to the instruction transmitted from the logic unit
Lock.
It is preferred that the execution unit also includes the second relay, second relay and the logic list
It is first to be connected with the circuit breaker electric, so as to control the breaker according to the instruction transmitted from the logic unit
Close a floodgate.
It is preferred that the collecting unit is arranged to carry out step-down treatment to the voltage gathered from the photovoltaic cable,
And send the magnitude of voltage after step-down is processed to the logic unit.
It is preferred that the header box protection device also include secondary power supply, the secondary power supply respectively with it is described
Collecting unit, logic unit and execution unit electrical connection so as to for the collecting unit, logic unit and
Execution unit provides electric energy.
It is preferred that the comparison voltage is equal to the 17/41-20/41 of the open-circuit voltage of photovoltaic group string branch road.
It is preferred that the comparison voltage is equal to 380V-400V, and the setting value is equal to 190V-320V.
It is preferred that the comparison voltage is equal to 400V, and the setting value is equal to 200V.
To sum up, by header box protection device of the invention, can effectively be controlled when photovoltaic cable is directly grounded
Breaker open operation processed, so as to solve because of a series of problems that photovoltaic cable ground connection causes, and occurs in header box
When photovoltaic cable is through transition resistance eutral grounding failure, header box protection device of the invention has when endangering larger
Effect control breaker open operation, and destroy it is little when be then failure to actuate, prevent because shutdown and caused by economic loss.
Brief description of the drawings
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 diagram of header box protection device according to an embodiment of the invention；
Fig. 5 A-5B show the main circuit diagram of logic unit of the invention；And
Fig. 6 is each unit connection diagram of header box protection 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 accompanying drawing, to become apparent from understanding this
The objects, features and advantages of invention.It should be understood that embodiment shown in the drawings is not to model of the present invention
The limitation enclosed, and simply to illustrate that 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 one-level to conflux, for subtracting
Few photovoltaic array is linked into the line of inverter, while lightning protection function is provided, the running status of detection photovoltaic panel,
DC quantity state acquisition and circuit-breaker status etc..
Photovoltaic DC-to-AC converter：Photovoltaic DC-to-AC converter is connected by power electronic devices (MOSFET, IGBT etc.)
Connecting resistance electric capacity, the break-make of control device in the way of pulse width modulation, the direct current that header box transmission is come
Electricity is transformed into alternating current, while completing the MPPT maximum power point tracking (MPPT) of photovoltaic module, it is ensured that function
Control and anti-islanding effect etc..
Breaker：Designed coupling or uncoupling means, can close, break-make and carry normal condition electric current；And
And can be under abnormal operational conditions, it is also possible to closed, the conducting in disjunction and certain hour with it is logical
It is disconnected.
Photovoltaic generating system, its electrical schematic diagram is shown in 1.From figure 1 it appears that being connected with header box
Be photovoltaic cable and direct current cables.The connection that photovoltaic cable is used between photovoltaic module group string.Direct current cables
For the connection between header box and photovoltaic DC-to-AC converter.
Fig. 2 shows occur the situation of earth fault in the actual moving process of photovoltaic generating system.Such as Fig. 2
Shown, during photovoltaic plant actual motion, there is the probability highest of earth fault in photovoltaic cable certain point.
When solar irradiation is mapped to the surface of photovoltaic module, it absorbs the photon with certain energy, in component
Inside produces the electron-hole pair in non-equilibrium state；In the presence of P-N junction internal electric field, electronics,
Hole is tended to N, P knot respectively, so as to be formed about the photoproduction in opposite direction with built in field in P-N junction
Electric field；Redundance after photoproduction electric field neutralisation P-N junction built in field makes P, N area respectively with positive and negative
Point, then produces the photo-induced voltage that P areas are pointed to by N areas, i.e. photovoltaic module voltage in Fig. 1；When outer
Then there is electric current to be flowed out from P areas after connecing load, photovoltaic cell is flowed into through loading from N areas, its schematic diagram is shown in Fig. 3.
Because P-N junction is the influence of zero reference point, under normal operating conditions, the amplitude of positive and negative electrode voltage is equal,
It is the half of photovoltaic module voltage.
In Fig. 2, when A points occur earth fault, the voltage of header box positive pole copper bar side is close to 0.By
It is the reference point not being grounded in P-N junction, the voltage of header box negative pole copper bar side is the voltage of photovoltaic module.It is negative
Skyrocketing for pole copper bar side voltage, can cause the device inside header box breakdown in case of high pressures, so that
Trigger fire.But, the protection such as electric current, overload that breaker is furnished with this stage can not be acted and disconnected
Breaker.Therefore, inventor has invented header box protection device of the invention.
As shown in figure 1, header box generally includes photovoltaic cable, header box fuse, copper bar and breaker.
Wherein, photovoltaic cable is connected with photovoltaic group string, photovoltaic group string by photovoltaic cable parallel connection after again by copper bar with
Breaker is connected, and header box fuse is set on photovoltaic cable.
Header box protection device of the invention generally includes collecting unit, logic unit and execution unit.Adopt
Collection unit is electrically connected with photovoltaic cable, so as to gather the magnitude of voltage of the photovoltaic cable.Logic unit is single with collection
Unit's electrical connection, and the magnitude of voltage transmitted from collecting unit is received, then the magnitude of voltage and reference voltage level are entered
Row compares, when the absolute value of the magnitude of voltage and the difference of reference voltage level is more than or equal to setting value, to execution
Unit sends instruction.Execution unit controls breaker open operation according to the instruction transmitted from logic unit, so that
Obtaining header box will not be damaged because photovoltaic cable is grounded.
Header box protection device of the invention is described in detail below in conjunction with the accompanying drawings.
Embodiment 1
Fig. 4 is the header box protection device each unit connection diagram according to the present embodiment.As shown in figure 4,
Header box protection device 100 includes collecting unit 10, logic unit 20 and execution unit 30.Wherein,
Collecting unit 10 is electrically connected with the positive pole 41 of photovoltaic cable and the negative pole 42 of photovoltaic cable respectively by wire.
Logic unit 20 is by wire and the electrical communication of collecting unit 10.Execution unit 30 is by wire and logic list
Unit 20 is in electrical communication.
As shown in figure 4, the collecting unit 10 of the present embodiment is electrical voltage system measurement apparatus, can be VSM
Or DC/DC voltage drop elements, the positive pole 41 of its collection photovoltaic cable and the voltage U of negative pole 42+And U-, and
To gathering the voltage U for coming+And U-Step-down treatment is carried out, to gathering the voltage U for coming+And U-Carry out at step-down
After reason, then the magnitude of voltage after treatment is passed into logic unit, hereafter will be described in detail.In fig. 4, PE
Zero reference point is represented, GND represents protective grounding, and secondary power supply 50 is powered for collecting unit 10.
Fig. 5 A, 5B are the main circuit diagram of logic unit.As shown in Fig. 5 A, 5B, logic unit is main
Including comparator 21,22, wherein, Fig. 5 A show the comparator 21 being connected with the positive pole of photovoltaic cable, figure
5B shows the comparator 22 being connected with the negative pole of photovoltaic cable.
Fig. 5 A show comparator 21, resistance R1、R2And R3, wherein, resistance R1One end pass through wire
Electrode input end with comparator 21 is connected, resistance R1The other end be wired to collecting unit 10,
And received by the voltage U after step-down treatment from collecting unit 10+。R2One end pass through wire and comparator
21 negative input connection, the other end receives comparison voltage U by wireN.The output end of comparator 21
Electrically connected with execution unit 30, instructed so as to be sent to execution unit.
Fig. 5 B are similar with Fig. 5 A, the difference is that only that the electrode input end of comparator 22 is connected by wire
Collecting unit 10 is connected to, and is received by the voltage U after step-down treatment from collecting unit 10-.Such as Fig. 5 B
It is shown, resistance R4One end be connected with the electrode input end of comparator 22 by wire, resistance R4It is another
One end is wired to collecting unit 10, and is received by the electricity after step-down treatment from collecting unit 10
Pressure U_。R5One end be connected with the negative input of comparator 22 by wire, the other end is connect by wire
Receive comparison voltage UN, comparison voltage UNOpen-circuit voltage according to photovoltaic group string branch road determines.Hereafter will be detailed
Thin description.The output end of comparator 22 is electrically connected with execution unit 30, so as to be sent to execution unit 30
Instruction.
Logic unit 20 is used for comparison voltage U+、U-With reference voltage UNSize.Wherein, comparator
21 are used for comparison voltage U+With UNSize, comparator 22 be used for comparison voltage U-With comparison voltage UN
Size.When meeting Biao Da Shi ∣ UN-U+∣ >=ε Huo ∣ UN-U-During ∣ >=ε (ε is setting value),
Can be determined that photovoltaic cable is grounded, certainly, also including the situation of direct current cables ground connection.
Execution unit 30 mainly includes relay J1, relay J1 and logic unit 20 and the electricity of breaker 60
Connection, when logic unit 20 sends separating brake to relay J1 to be instructed, relay J1 controlling switches 31 are closed
Close, so as to control the separating brake of breaker 60.
The photovoltaic cable ground connection or direct current cables ground connection of header box include being directly grounded and through transition resistance eutral grounding,
Be directly grounded refer to photovoltaic cable be directly connected on the ground, refer to photovoltaic cable through transition resistance eutral grounding and pass through
One resistance is grounded again, therefore, the voltage of the photovoltaic cable collected when photovoltaic cable is directly grounded is 0,
The value of the voltage collected when photovoltaic cable is through transition resistance eutral grounding is additionally depended on by the electricity of resistance eutral grounding
The size of resistance.
But, found by substantial amounts of engineering practice in inventor, in the case of through transition resistance eutral grounding,
If this is sufficiently large through the resistance of transition resistance eutral grounding, that causes is dangerous minimum, therefore, basis of the present invention
The actual conditions of engineering practice,
By UNThe 17/41-20/41 that photovoltaic group passes the open-circuit voltage of branch road is equal to, ε is set to
In 0.4UN-0.8UN, good effect can be obtained.Such as, when the open-circuit voltage etc. of photovoltaic group string branch road
When 820V, UNEqual to 380V-400V, ε is equal to 0.4UN-0.8UN.It is preferred that in photovoltaic group string
When the open-circuit voltage of branch road is equal to 820V, by UN400V is set to, ε is set to 200V.
In the header box course of work, in the event of the situation that photovoltaic cable is directly grounded, due to photovoltaic electric
Cable is directly grounded, and the voltage of earth point is 0, therefore, the U collected by collecting unit+Or U-Equal to 0,
Now, logic unit Pan Duan Chu ∣ UN-U+∣ >=ε Huo ∣ UN-U-∣ >=ε so that, logic unit to
Execution unit sends separating brake instruction, after logic unit receives separating brake instruction, controls to open by relay J1
Close 31 to close, so as to control breaker open operation.Therefore avoid header box and cause serious because of ground connection
Consequence.
In the event of situation of the photovoltaic cable through transition resistance eutral grounding, now, such as fruit ∣ UN-U+∣≥ε
Huo ∣ UN-U-∣ >=ε, then logic unit send separating brake to execution unit and instruct, logic unit is received point
After lock instruction, closed by relay J1 controlling switches 31, so that the breaker open operation of header box is controlled,
So as to avoid header box serious consequence is caused because of ground connection.And if Bu Man Zu ∣ UN-U+∣ >=ε or
∣UN-U-∣ >=ε, then can without treatment because this kind of situation can't cause big destruction so that
Reduce to greatest extent because of shutdown and caused by loss.
Embodiment 2
Fig. 6 is each unit connection diagram of the header box protection device according to the present embodiment.Referring to figure
6 describe the header box protection device 200 of the present embodiment.Embodiment 2 mainly exists with the difference of embodiment 1
In, execution unit 30 also includes that relay J2, relay J2 are electrically connected by wire with logic unit, from
And the reclosing command that logic unit sends is received, and when the reclosing command of logic unit transmission is received, control
Breaker closing.
During header box works, in the event of photovoltaic cable ground connection, so that breaker is performing list
When being disconnected under the control of unit, after people finder goes out earth fault and solution problem with grounding at the scene, in reality
Applying can be by manually by breaker closing, in example 2 by logic unit to relay J2 in example 1
Reclosing command is sent, relay J2 controlling switches 32 after reclosing command is received are closed, so as to control to break
Road device closes a floodgate.
To sum up, by header box protection device of the invention, can effectively be controlled when photovoltaic cable is directly grounded
Breaker open operation processed, so as to solve because of a series of problems that photovoltaic cable ground connection causes, and occurs in header box
When photovoltaic cable is through transition resistance eutral grounding failure, header box protection device of the invention has when endangering larger
Effect control breaker open operation, and endanger it is little when be then failure to actuate, prevent because shutdown and caused by economic loss.
Below presently preferred embodiments of the present invention has been described in detail, it is understood that reading this hair
After bright above-mentioned instruction content, those skilled in the art can make various changes or modifications to the present invention.
These equivalent form of values equally fall within the application appended claims limited range.
Claims (10)
1. a kind of header box protection device, the header box includes photovoltaic cable and breaker, and its feature exists
In the header box protection device includes collecting unit, logic unit and execution unit；The collection is single
It is first to be electrically connected with the photovoltaic cable, and for gathering the voltage signal of the photovoltaic cable；The logic unit
Electrically connected with the collecting unit so as to receive the voltage signal transmitted from the collecting unit, then by the electricity
Pressure signal is compared with comparison voltage, when the voltage signal is more than or waits with the absolute value of the difference of comparison voltage
The logic unit sends to the execution unit and instructs when setting value；And the execution unit with it is described
Logic unit electrical connection simultaneously controls the breaker open operation according to the instruction transmitted from the logic unit.
2. header box protection device according to claim 1, it is characterised in that the comparison voltage
Equal to 1.25-2 times of the setting value.
3. header box protection device according to claim 1, it is characterised in that the logic unit
Including comparator, the comparator is electrically connected with the collecting unit and the execution unit respectively.
4. header box protection device according to claim 3, it is characterised in that the logic unit
Also include first resistor and second resistance, the first resistor and second resistance pass through wire and the ratio respectively
Positive and negative input compared with device is connected, and the resistance of the first resistor and the second resistance is equal.
5. header box protection device according to claim 1, it is characterised in that the execution unit
Including the first relay, first relay is connected with the logic unit and the circuit breaker electric, and root
The breaker open operation is controlled according to the instruction transmitted from the logic unit.
6. header box protection device according to claim 5, it is characterised in that the execution unit
Also include the second relay, second relay is connected with the logic unit and the circuit breaker electric, from
And the breaker closing is controlled according to the instruction transmitted from the logic unit.
7. header box protection device according to claim 1, it is characterised in that the collecting unit
It is arranged to carry out the voltage gathered from the photovoltaic cable step-down treatment, and by the electricity after step-down is processed
Pressure value sends the logic unit to.
8. header box protection device according to claim 1, it is characterised in that the header box is protected
Protection unit also includes secondary power supply, the secondary power supply respectively with the collecting unit, logic unit and hold
The electrical connection of row unit for the collecting unit, logic unit and execution unit so that provide electric energy.
9. header box protection device according to claim 1, it is characterised in that the comparison voltage
Equal to the 17/41-20/41 of the open-circuit voltage of photovoltaic group string branch road.
10. header box protection device according to claim 1, it is characterised in that the comparison voltage
190V-320V is equal to equal to 380V-400V, and the setting value.
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 true CN106936112A (en) | 2017-07-07 |
| CN106936112B CN106936112B (en) | 2019-09-06 |
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ID=59441661
Family Applications (1)
| 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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| Country | Link |
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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 |
|---|---|
| CN106936112B (en) | 2019-09-06 |
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