Conflux detection method and system, solar power station for header box
Technical field
The present invention relates to field of solar thermal power generation, and in particular to a kind of conflux detection method and system for header box,
And a kind of solar power station.
Background technology
With the worsening shortages of the energy, the exploitation of renewable green energy resource are increasingly paid close attention to by people, especially with
The utilization of solar energy is especially favored by common people.Solar energy is used as cleaning, safe, the sustainable and reliable energy, the sun
Energy photovoltaic system is expanding rapidly its application in terms of the energy and industrial technology exploitation.In recent years, change as solar energy
The development and application of the photovoltaic cell of medium and large area photovoltaic module device causes common concern.With monocrystalline silicon, polysilicon,
Amorphous silicon membrane etc. for representative extensive application of the solar panel in business and the facility such as residential building show huge
Big potentiality, such as thin film solar photovoltaic template can replace some building elements, such as building wall, window etc..
Solar energy photovoltaic system power generation situation directly affects the economic benefit of enterprise, occurs such as in the photovoltaic system course of work
Fault can substantially reduce photovoltaic system generating capacity, affect business economic interests.In actual applications for different projects, light
The arrangement of photovoltaic array is different, and this real-time monitoring just to photovoltaic array and fault diagnosis bring certain difficulty, and solar-electricity
Whether normal work will directly influence safety and the gross generation of solar power station to pond group string, therefore to each solar cell
The real-time current of group string is monitored and its fault diagnosis is just particularly necessary.
At present, the solar panel species in industry is various, differs greatly, for different designs side in terms of component parameter
Case, also using the inverter of multi-form, and can have the arrangement of distinctive photovoltaic array according to project characteristic.In view of these are former
Cause, the building form of photovoltaic array are varied, cause each solar battery group string operating characteristic in photovoltaic array to differ greatly,
Therefore it is difficult to single foundation component characteristic or arrangement mode delimited to solar battery group string working condition and determine numerical value model
Enclose.Diagnosis in prior art for photovoltaic system is confluxed just for one-level, can not be examined for end is individually entered
Disconnected, for the solution that do not had of working condition of photovoltaic solar cell group string.The method of existing diagnosis has:
1st, electric current average determining method
Using whether the mean value of current value undergos mutation judge whether to break down, if< makes a reservation for
Value, then it is assumed that normal, otherwise explanation are undergone mutation as exception, wherein InFor the current value of the input n of header box,A is input number, the i.e. I of header boxaveTake be the input current value of this header box and divided by this
The fan-in of header box, and do not consider upper level header box that each input connected or solar battery group string
Quantity is different, causes judged result inaccurate.For example for certain three-level header box, both existed and be directly connected to solar battery group string
Input, there is also the input of two grades of header boxs of connection, and two grades of header boxs also both existed and were directly connected to solar cell
Group string input, there is also connection one-level header box input when, judged using above-mentioned electric current average determining method
When, each input electric current for three-level header box takes average and is judged obviously substantial deviation real work situation, because
The current value of the input of two grades of header boxs of connection of three-level header box should be far longer than and be directly connected to solar battery group string
The current value of input, easily causes fault misdescription after taking average.And, when calculating typically by header box in prior art
All inputs all include calculating, and do not consider untapped input (vacant input), and this can increase further and judge knot
Fruit and the deviation of actual conditions.
2nd, fuse alarm method
When the current loop current value for being monitored is zero, then " fuse alarm " is produced, the wherein drift value can be set.
This kind of method defect is:For the time-division of daily morning and evening, by illumination or shadow effect, it is most likely that some sun
It is that solar battery group string electric current is less that energy battery pack string still generates electricity, and some components are not generated electricity.According to diagnostic rule,
Solar battery group string to not generating electricity will produce fuse alarm, and the solar battery group string that warning does not generate electricity occurs in that different
Often, and actually this phenomenon is normal, and the component not generated electricity is also still in normal operating conditions.
It can be seen that, existing this fuse alarm decision logic will introduce daily wrong report.
3rd, the out-of-limit method of electric current low value
The out-of-limit method of estimated current low value be by certain one-level header box all inputs to actually enter electric current in average
Value is multiplied by a safety coefficient (typically taking 50%) more than 0 less than 1 and is judged as lower limit value Imin.When a certain input
Electric currentOutputting alarm signal, wherein, n is the circuitry number of actual this grade of header box of access.
This kind of method defect is:For multistage monitoring of confluxing, before in header box, the current value of each input is probably
The sum of the multi-string battery component electric current that the multistage header box in face is accessed.For example for two grades of monitoring of confluxing, in two grades of header boxs each
The current value of input is the multi-string battery component electric current sum that one-level header box is accessed.As position of arranging is different, same
The number of the solar battery group string accessed by each input of two grades of header boxs may be different, and for example input 1 passes through one-level
Header box accesses 5 string battery components, and input 2 accesses 3 string components by one-level header box.In this case, it is all defeated
Enter the unified lower limit value that a fixation is set in end and cannot just meet the needs for using.Additionally, the installation site of percentage of batteries component
In the afternoon or some moment may be blocked by building, the electric current of the battery component output being blocked will be significantly lower than other batteries
The electric current of component output, this is normal operating conditions, should not outputting alarm information.But the out-of-limit method of current this electric current low value
Meeting will be in normal operating conditions but output current produces mistake less than header box or the solar battery group crossfire police of lower limit value
Report.Even for the photovoltaic plant that only one-level is confluxed, some battery components are in the afternoon, morning or some moment be likely to be built
Build thing to block, when there are indivedual solar battery group string output loop electric currents significantly lower than other loops, the criterion is produced
Warning information is still likely to be wrong report.The alarm signal that this change because of natural conditions is produced, can cause higher wrong report
Rate.
4th, the out-of-limit method of electric current high level
The out-of-limit method of estimated current high level be by certain one-level header box all inputs to actually enter electric current in average
Value is multiplied by a safety coefficient (generally 150%) more than 1 and is judged as ceiling value Imax.Electricity when a certain input
StreamOutputting alarm signal, wherein, n takes this grade of header box circuitry number of actual access.
This kind of method defect is similar to the deficiency of the out-of-limit method of electric current low value described above.For example, for two grades of prisons that conflux
Control, in two grades of header boxs, the current value of each input is the sum of the multi-string battery component electric current that one-level header box is accessed.Due to
Arrangement position is different, and the solar battery group string number accessed by each input of same two grades of header boxs may be different.?
In this case, be all inputs unification arrange a fixation ceiling value will be unable to meet the needs for using.Additionally, part
The installation site of battery component earlier or may be more exposed to sunlight than other battery components in the morning or some moment
Under, then by the electric current apparently higher than other battery component outputs, this is normal work to the electric current of exposed battery component output
State, should not outputting alarm information.But the out-of-limit method of current this electric current high level can will be in normal operating conditions but output
Electric current produces wrong report more than header box or the solar battery group crossfire police of ceiling value.Even for the light that only one-level is confluxed
, in the afternoon, in the case that morning or some moment power stations blocked by building, can there is part solar-electricity therein in overhead utility
, early than other battery strings exposure situations in the sun, now the electric current of indivedual solar battery group string output loops will for pond group string
Apparently higher than other loops, the warning information that the criterion is produced still is likely to be wrong report.This change because of illumination condition
The alarm signal of generation, can cause higher rate of false alarm.
Also exist using whether current changing rate undergos mutation to judge whether to produce DC Line Fault electric arc in prior art
Technical scheme, the technical scheme can reduce false drop rate.But, first, this technical scheme only takes into account a road electric current
Rate of change, can cause the curent change of solar battery group string in view of building as above situations such as do not block, therefore
Barrier false drop rate is still higher;Secondly, in the case of it there is multistage header box, the technical scheme is only applicable to afterbody and confluxes
Current acquisition and detection between the output end of case and inverter, and single solar battery group string or upper can not be directed to
The fault of level header box is detected that so, technical staff is to know to there occurs fault, but is not aware that fault occurs at what
Place.
No matter any of the above described detection method, is all that to header box is individually defeated in time domain or frequency domain
Entering end or output end carries out the contrast of current value or rate of change, it is impossible to exclude the impact that environmental factor is caused, cailure rate of false positives
Higher.
Content of the invention
The purpose of the present invention is to reduce the fault false drop rate in photovoltaic system, is this The embodiment provides as follows
Technical scheme:
A kind of detection method of confluxing for header box, the header box include multiple inputs and an output end, per
Individual input connection solar battery group string or the output end of upper level header box, methods described include:Sense each input
Current value;IfThe judged result of < first predetermined value is no, then judge the solar cell of the input connection
Group string or upper level header box be in abnormal operation, otherwise the rate of change of calculating current value and enter next step judgement,
Wherein InFor the current value of the input,A is the solar battery group string of the actual connection of the input
Number, b is the number of the solar battery group string of the actual connection of the header box, m be the input of the header box
Number;Judge whether the rate of change of current value of the input less than second predetermined value, or the current value of the input
Rate of change is more than third predetermined value, and less than zero, the third predetermined value is more than zero to wherein described second predetermined value, if it is not, then
Judge that the solar battery group string of the input connection or upper level header box are in normal operating conditions.
Preferably, the detection method of confluxing also includes:If the rate of change of the current value of the input is less than second
Predetermined value, judges whether the rate of change of current value of adjacent or close one or more of the other input again smaller than described
Two predetermined values, or if the rate of change of the current value of the input is more than third predetermined value, judge whether adjacent or phase
The rate of change of the current value of near one or more of the other input is also greater than the third predetermined value, if it is, judging to be somebody's turn to do
The solar battery group string of input connection or upper level header box are in normal operating conditions, if it is not, then judging the input
The solar battery group string of end connection or upper level header box are in abnormal operation.
Preferably, the detection method of confluxing also includes:Solar battery group string or upper one if there are input connection
Level header box is in abnormal operation, then alerted.
A kind of detecting system of confluxing for header box, the header box include multiple inputs and an output end, per
Individual input connection solar battery group string or the output end of upper level header box, the detecting system of confluxing include:Electric current sense
Unit is surveyed, for sensing the current value of each input;Data processing unit, for calculating the change of the current value of each input
Rate;Judging unit, the current value of each input for being sensed according to the current sensing unit judge that the input connects
Whether the solar battery group string for connecing or upper level header box are in normal operating conditions, if< first is pre-
The judged result of definite value is no, then judge that the solar battery group string of the input connection or upper level header box are in abnormal
Working condition, otherwise enters next step and judges, wherein InFor the current value of the input,A is described defeated
Enter the number of the solar battery group string of the actual connection in end, b is the individual of the solar battery group string of the actual connection of the header box
Number, m is the number of the input of the header box;Judge whether that the rate of change of the current value of the input makes a reservation for less than second
Value, or the rate of change of the current value of the input is more than third predetermined value, wherein described second predetermined value institute less than zero
Third predetermined value is stated more than zero, if it is not, then judging at solar battery group string or the upper level header box of the input connection
In normal operating conditions.
Preferably, the judging unit is additionally operable to:If the rate of change of the current value of the input makes a reservation for less than second
Value, judges whether that the rate of change of the current value of adjacent or close one or more of the other input is pre- again smaller than described second
Definite value, or if the rate of change of the current value of the input is more than third predetermined value, judge whether adjacent or close
The rate of change of the current value of one or more of the other input is also greater than the third predetermined value, if it is, judging the input
The solar battery group string of end connection or upper level header box are in normal operating conditions, if it is not, then judging that the input connects
The solar battery group string for connecing or upper level header box are in abnormal operation.
Preferably, the detecting system of confluxing also includes:Alarm Unit, for judging there is input in the judging unit
The solar battery group string of connection or upper level header box are alerted after abnormal operation.
A kind of solar power station, the solar power station include solar battery group string, N level header box and as above institute
The detecting system of confluxing that states, wherein N are the integer more than or equal to 2, wherein except one-level header box input directly with described too
Sun can battery pack series winding connect outer, other any level header boxs at least one described in input and upper level header box output end
Connection, the detecting system of confluxing detect that to confluxing for header boxs at different levels the output current of N level header box is through inverter
Access grid-connected point.
When the method and system of the embodiment of the present invention carry out average to the input of header box and judge, take into full account that this is defeated
Enter the solar battery group string number of the end different and actual connection of the header box of connected solar battery group string number not
With, and avoiding problems the abnormal change of the front solar battery group string for causing of only input of this grade of header box being averaged
Change and be attenuated or even ignore, when it also avoid header box and not only having connected upper level header box but also be directly connected to solar battery group string
IaveCalculating affected by abnormal battery pack string and cause to judge the fault of normal solar battery group string by accident, so as to improve
Breakdown judge accuracy.And average judge after, further using adjacent or close input current value rate of change come
Mutually verified, if the rate of change of the current value of a certain input there occurs that low value is out-of-limit or high level is out-of-limit, and adjacent
Or the synchronous generation low value of the rate of change of the current value of other close inputs is out-of-limit or high level is out-of-limit, then it is assumed that cause this electricity
The reason for mutation of flow valuve is that adjacent or close solar battery group string is simultaneously entered or leaves shadow occlusion, still believes that
The solar battery group string of input connection or upper level header box normal, it is to avoid become using the electric current of input itself
The fault erroneous judgement that rate is brought.
And, the present invention is that the input input current to header box is sensed, i.e. each input electricity to header box
Stream detected, can more accurately judge trouble point, so as to be overhauled.
Description of the drawings
Next accompanying drawing will be combined to be described in further detail the specific embodiment of the present invention, wherein:
Fig. 1 is that the bus structure of the solar power plant using two grades of photovoltaic arrays that conflux of embodiments of the invention is illustrated
Figure;
Fig. 2 is the flow chart of the detection method of confluxing of embodiments of the invention;
Fig. 3 is the structural representation of the detecting system of confluxing of the solar power plant of embodiments of the invention.
Specific embodiment
With reference to Fig. 1, shown in figure is a part for a solar power plant, that is, illustrate only two-stage and conflux composition
A part for photovoltaic array, in actual applications, the photovoltaic array can continue to increase and conflux rank.Photovoltaic battle array in the present embodiment
In row, assembly connecting mode is:X (x >=1) solar panel constitutes a solar battery group string, enters 1 one-level using n
Conflux, will n solar battery group string confluxed to input n by the input 1 of same one-level header box, while
Enter two grades of 1 using m again to conflux, will the electric current of output end output of m one-level header box pass through same two grades of header boxs
Input 1 confluxed to input m, finally unify by two grades of header boxs output end export.I represents header box and is respectively input into
The current value of end input.I represents the output current value of header box output end, and the current value is also equal to the corresponding of next stage header box
Input input current value.N represents the maximum solar battery group string quantity that one-level header box can be accessed, such as type
Number enter 1 one-level header box for 8, be up to 8 inputs, 8 solar battery group strings are at most can access, when actually used not
Same one-level header box may actually access solar battery group string quantity difference, such as Z1-H1 header box in exact arrangement
Reality is only connected to 7 inputs connection solar battery group strings, and Z1-H2 header box is actual to be connected with 6 input solar-electricity
Pond group string.M represents two grades of header boxs and is connect the maximum branch road quantity that can be accessed, and such as enters 1 two grades of header boxs for model 10, most
There are 10 inputs more, can at most connect the output end of 10 one-level header boxs.If one-level header box is 8 models for entering, that
The electric current of this 10 two grades of each input of header box for entering 1 will be the output of an one-level header box, be 8 solar-electricity
The sum of pond group string electric current, the output current of whole two grades of header boxs are preferably at most the sum of 80 solar battery group string electric currents.In reality
The solar battery group string quantity that different two grades of header boxs during the use of border actually may be accessed in exact arrangement is different, such as Z1
Header box is actually only connected to 9 one-level header boxs, and the input 1 of Z1 header box connects the output end of Z1-H1 header box, and Z1 confluxes
The input 2 of case connects the output end of Z1-H2 header box, the like.Or, Z1 header box is removed and is connected with one-level header box
Outward, also there is the input for being directly connected to solar battery group string.That is, for one-level header box Z1-H1 to Z1-Hm,
In n input of one-level header box, multiple or fully enter end and contact with solar battery group and connect, and allow one-level to conflux
There is vacant input in case;And for two grades of header box Z1, the output end of at least one input and one-level header box
Connect other inputs can with solar battery group series winding connect, or two grades of header boxs as shown in Figure 1 all defeated
Enter end 1 to input m to be connected with one-level header box Z1-H1 to Z1-Hm respectively, and allow the presence of vacant input.Higher level
Other header box the like until N level (N is integer and N >=2).
In in the present embodiment photovoltaic array adopted by solar power station, each subcircuits of header boxs at different levels have with ShiShimonoseki
System:
1st, for one-level header box:By taking Z1-H1 header box as an example, the electric current of its output end is had with the current value of input
Following relation:IZI-H1=i11+i12+···+i1n.Z1-H1 header box has n input, and each input only connects a string
Solar battery group string, then the current value of its each input is exactly the output current of each connect solar battery group string, i.e.,:
Input 1, I for Z1-H11=i11;Input 2, I for Z1-H12=i12;Input n, I for Z1-H1n=
i1n;Input n, I for Z1-Hmn=imn.
2nd, for two grades of header boxs:By taking Z1 header box as an example, the current value of its output end is had with the current value of input
Following relation:IZI=i1+i2+···+im.Wherein, i1For the input current value of the input 1 of two grades of header box Z1, the electric current
The output current value I of output end of the value equal to one-level header box Z1-H1ZI-H1, i2To imThe like, for convenience, here is still
The input current value of the input 1 of two grades of header box Z1 is expressed as I1... by the input of the input m of two grades of header box Z1
Current value is expressed as Im.Z1 header box has m input, and each input connects an one-level header box, then two grades
The current value of each input of header box Z1 is exactly the current value of the output end of the one-level header box for each being connected, actually
Be n solar battery group string current value and, i.e.,:The i of two grades of header boxsInput 1=I1=i1=IZI-H1=i11+i12
+···+i1n... ... iInput m=Im=im=IZI-Hm=im1+im2+···+imn.And if Z1 header box had both been present directly
Connect the input of solar battery group string in succession, there is also the input of connection one-level header box, the then output of Z1 header box
The current value at end is equal to the current value of the solar battery group string for directly connecting and the electricity of the output end of each one-level header box
Flow valuve sum.
For the header box of the higher level of N > 2, calculation the like, no longer describe in detail herein.N level header box
Output end electric current through the access grid-connected point of inverter, enter power supply grid.
In this application, the input of " adjacent or close " refers to the solar battery group string for connecting or upper level converges
The stream adjacent or close input of case physical location, Z1-H1 header box for example in FIG, although the input of the header box
It is separated by a plurality of input between end 1 and input n, but if the solar battery group string that connected of input 1 and input n institute
The solar battery group string physical location of connection is adjacent or close, then it represents that input 1 is adjacent with input n or close.Thing
The adjacent or close solar battery group string in reason position or header box experience the change of identical illumination condition substantially, for example same
The shadow occlusion process of Shi Jingli building or the successively shadow occlusion of experience same building thing.
Next will describe in detail by taking the flow process in Fig. 2 as an example to enter the header boxs at different levels in the solar power station in Fig. 1
The method of capable detection of confluxing.
Assume:The input number of two grades of header box Z1 is 3, i.e. m=3;The input number of one-level header box Z1-H1 is
The n=5 of 5, i.e. Z1-H1;The input number of one-level header box Z1-H2 is the n=3 of 3, i.e. Z1-H2;Two grades of header box Z1's is defeated
Enter end and 3 be directly connected to solar battery group string, it is also possible to which the input number for thinking one-level header box Z1-H3 is 1 (actually Z1
Input 3 and be not connected to one-level header box).
First, S1 step is carried out:The current value of each input of sensing header box Z1.Here, " each input " refers to converge
The input for being connected with solar battery group string or upper level header box of stream case, and do not consider vacant input.For example at this
In embodiment, two grades of header box Z1 have 8 inputs, and only consider its input 1, input 2 and input 3.
After the current value for obtaining each input, S2 step is entered:Average judges.
Average judge content be:InequalityWhether < first predetermined value is set up, wherein InConflux for two grades
The current value of the input n of case Z1, IaveFor electric current average,A is the solar-electricity of the actual connection of input n
The number of pond group string, b are the number of the solar battery group string of the actual connection of two grades of header box Z1, and m is two grades of header box Z1
The number of input.For example, the input number of two grades of header box Z1 is 3, m=3;The input 1 of two grades of header box Z1 connects
The solar battery group string number of the input connection of the upper level header box Z1-H1 for connecing actually connects for the input 1 of 5, i.e. Z1
The solar battery group string number for connecing is 5, a=5;Similarly, the solar battery group of the actual connection of the input 2 of header box Z1
String number a=3;Similarly, solar battery group string number a=1 of the actual connection of the input 3 of header box Z1.Therefore for
For two grades of header box Z1, b=5+3+1=8.For three-level header box, the solar energy of the actual connection of each input
Battery pack string number a is two grades of header boxs of input connection, the solar energy in the one-level header box of two grades of header box connections
The sum of battery pack string number, and solar battery group string number b of the actual connection of the three-level header box is the three-level header box institute
There is the number of the solar battery group string of the actual connection of input.For example, input number m=2 of certain three-level header box, wherein
Input 1 connects two grades of header boxs, and input 2 connects solar battery group string, the input of two grades of header boxs that input 1 connects
End number is 2, and wherein input 1 connects one-level header box, and input 2 connects solar battery group string, and one-level header box connects
Connect 5 solar battery group strings, then for the three-level header box, m=2, the solar battery group of the actual connection of input 1
String number a=5+1=6, solar battery group string number a=1 of the actual connection of input 2, the actual connection of the three-level header box
Solar battery group string number b=5+1+1=7.The header box of higher level the like, no longer describe in detail herein.
If the judged result of S2 step is no, then prove that the input electric current average generates mutation, judging should
The solar battery group string of input connection or upper level header box are in abnormal operation.The reason for abnormal operation
It is from the open circuit of solar battery group string or the performance difference of different manufacturers, the solar panel of different batches
Deng the true fault that the unification of, here is considered as belonging to be detected.
In order to more clearly judge to judge to be contrasted with average of the prior art by the average of the present embodiment, now to same
One group of data is judged, and two kinds of determination methods take identical first predetermined value 0.6, comparing result such as Tables 1 and 2 institute
Show:
1 prior art average judged result of table
2 the present embodiment average judged result of table
By contrasting two kinds of results of Tables 1 and 2, judged using the average of prior art, for the defeated of header box Z1
Enter end 1, judged result is exception, but the current value of each input of header box Z1-H1 is all stable in 0.9A or so, and is as good as
Often, fault erroneous judgement is produced, is i the reason for erroneous judgement23By IaveValue drag down, but input 1 connect normal solar battery pack
String number is more, therefore I1Higher;For the input 2 of header box Z1, judged result is exception, but header box Z1-H2
The current value of input 3 is only 0.11A, header box Z1-H2 and has occurred that fault, be not judged out that reason is Z1-
I in H223Impact be attenuated in two grades of header boxs, and header box rank is higher, i23Impact decay tighter
Weight;For the input 3 of header box Z1, judged result is exception, but the input 3 of Z1 is only connected to a solar battery group
Go here and there and current value is in 0.9A or so and without exception, fault erroneous judgement is produced, reason is identical with the erroneous judgement reason of input 1.And adopt
After the average of the present embodiment judges, for header box Z1 each input judged result be actually consistent.Cause this difference
The reason for be that, average of the prior art only considers the current value of 3 inputs of two grades of header box Z1, and does not consider two
The number of the solar battery group string that 3 inputs of level header box Z1 actually connect simultaneously is differed, and produce fault
The header box rank that solar battery group string distance is detected is more remote, and its fault impact decay is more serious, so after averaging
Calculate again and erroneous judgement will be produced, and the electric current mean value computation mode in the present embodiment and judgment mode all take into account two grades and conflux
The difference of each input connection of case Z1, so as to obtain the result closer to truth, also, in this enforcement
I is calculated in exampleaveAnd aIaveWhen be the solar-electricity for breaking down directly with solar battery group string as calculating and judging object
The impact of pond group string directly can be found.In fact, if only carrying out average judgement to one-level header box, as one-level is converged
Each input of stream case is directly connected to solar battery group string, therefore a=1, b=m, now the average judged result of the present embodiment
Identical with the average judged result of prior art, but the header box for header box level n >=2, these high level header boxs
At least one input connects upper level header box, therefore a ≠ b, this will result in the judged result of the present embodiment with existing
Technology difference more advantage.And typically calculate I in the prior artaveWhen be consideration header box fully enter end (including sky
Put input), and the present embodiment only considers the input that there is annexation, therefore converges for the one-level that there is vacant input
For stream case, the average judged result of the present embodiment also can exist different and more accurate from prior art.
But, if in S2 stepThe judged result of < first predetermined value is yes, can't immediately arrive at too
Sun can battery pack string or upper level header box in the trouble-free conclusion of normal operating conditions because it is also possible to there is ring
Border factor affects and is not excluded.For example in table 1, one-level header box Z1-H1's that the input 1 of moment Z1 is connected is each
The current value of solar battery group string is in more than 0.9A, does not therefore detect working condition exception after the detection of S2 step, but
That the current value of more than the 0.9A is likely to be and abruptly reaches, the solar battery group string of such as other inputs suddenly with
The solar battery group string of the input is short-circuited, and should now report fault, if do not reported fault to be then fault missing inspection, Huo Zhe
The good situation next stage header box Z1-H1 of illumination condition has just left blocking for building effects, now should not report fault, such as
Report fault is then fault misdescription.Or, although at a time the current value of one-level header box Z1-H1 all reaches more than 0.9A,
But the illumination of very possible prevailing circumstances can reach the current value of 1.5A, actually due to the solar cell in battery pack string
Plate occurs open circuit or one-level header box Z1-H1 to initially enter building and block and be decreased to 0.9A from 1.5A.That is,
After the absolute value with the current value a certain moment of S2 step is judged as object, also it e insufficient to judge current value
Whether change breaks down.The current value of more than 0.9A as escribed above be abruptly reach (that is, the rate of change of current value is produced
Mutation), whether the mutation should be judged as normally, also needs to carry out ensuing calculating and judgement.
In order to reduce false drop rate further and improve recall rate, in the present embodiment, if the judged result of S2 step is
During "Yes", S3 step is also carried out:Calculate the rate of change of the current value of each input.After the rate of change for obtaining current value, then profit
The judgement of S4, S5 step is carried out with the out-of-limit determining method of high level, the out-of-limit determining method of low value.
Low value is out-of-limit to judge it is the variable quantity (i.e. the rate of change of current value) by comparing current value within the default time
To determine whether the mutation (negative sense mutation) of input electric current generation reduction suddenly, and whether mutation exceedes normal limit, next
Judge solar battery group string whether normal work.
Under normal circumstances, photovoltaic module output is relatively stable, does not have the operating current of fixation, and output current is with irradiation
Change and change.Under normal circumstances, the irradiation of sunlight is steady and continuous change, and is affected by diffusion etc., will not jump
Become, therefore under normal circumstances, the current value of solar battery group string output is relatively stable, will not be mutated, i.e. Z1-H1 header box
The electric current of each input will not be mutated.When faulty or damage, solar battery group string output current will occur significant change.
Therefore, it can the real-time current variable quantity of each input of Z1-H1 that connects by detection with solar battery group series winding to judge too
Sun can battery pack string whether normal work.If but have in same header box arbitrary neighborhood or close two-way or multichannel defeated
Enter end while when occurring the larger negative sense of electric current to be mutated, it may be possible to have object to block or cloud is sailed and caused, now should not export
Alarm.
The judgement the formula whether rate of change of current value occurs low value out-of-limit is:
As (in(t)-in(0)) < Imin=lin(0)When, judge that electric current low value is out-of-limit.Wherein, l is electric current low value limit coefficient,
L is less than zero, so as to lin(0)For a minus value, IminAlso it is a minus value, hereon referred to as second predetermined value.This
Variable l can pass through background maintenance software design patterns, and monitoring backstage real-time Communication for Power, l value can be directly downloaded to by 485 order wires
In equipment.N is integer, represents certain input in header box, and n is input sum to the maximum.When t is certain input timer
Between, this variable can pass through background maintenance software design patterns, and adjustable range needs to carry out different settings according to difference.That is, will
The rate of change of the current value of the input of one-level header box is compared with a minus second predetermined value, if rate of change
Less than second predetermined value, then judge that the solar battery group string of the input connection occurs low value out-of-limit, because rate of change is less than
Second predetermined value (second predetermined value be less than zero), then prove to there occurs the mutation that strongly reduces by input electric current that (rate of change is got over
Little, electric current reduces more violent).
High level is out-of-limit judge be by comparing the variable quantity of current value of the current value within the time for arranging (i.e. current value
Rate of change) determining whether that the electric current of input occurs to become suddenly big mutation (forward mutation assay), and whether mutation just exceedes
Normal limit value, judges solar battery group string whether normal work.
Under normal circumstances, photovoltaic module output is relatively stable, does not have the operating current of fixation, and output current is with irradiation
Change and change.Under normal circumstances, the irradiation of sunlight is steady and continuous change, and is affected by diffusion etc., will not jump
Become, therefore under normal circumstances, solar battery group string output current is relatively stable, will not be mutated, when faulty or damage, its
Output current will occur significant change.Therefore, it can judge too by detecting solar battery group string real-time current variable quantity
Sun can battery pack string whether normal work.If but have in same header box arbitrary neighborhood or close two-way or multichannel defeated
Enter end while when there is the larger forward mutation assay of electric current, it may be possible to because of solar battery group string just left shadow of object block or
Person's cloud is sailed and is caused, and does not now answer outputting alarm.
The judgement the formula whether rate of change of current value occurs high level out-of-limit is:
As (in(t)-in(0)) > Imax=hin(0)When, judge that electric current high level is out-of-limit, wherein, h is electric current high level limit coefficient,
H is more than zero, so as to hin(0)For a value more than zero, ImaxAlso it is a value more than zero, hereon referred to as third predetermined value, this
Variable h can pass through background maintenance software design patterns, and monitoring backstage real-time Communication for Power, h value can be directly downloaded to by 485 order wires and set
In standby.N is integer, represents certain input in header box, and n is input sum to the maximum.When t is certain input timer
Between, this variable can pass through background maintenance software design patterns, and adjustable range needs to carry out different settings according to difference.That is, will
The rate of change of the current value of the input of one-level header box is compared with a third predetermined value more than zero, if rate of change
More than third predetermined value, then judge that the solar battery group string of the input connection occurs high level out-of-limit, because rate of change is more than
Third predetermined value (third predetermined value be more than zero), then prove to there occurs the mutation that is increased dramatically by input electric current that (rate of change is got over
Greatly, electric current increases more violent).
Complete high level out-of-limit judgement with low value out-of-limit judge after, if input electric current do not occur high level out-of-limit or
Low value is out-of-limit, i.e., in S4 step, " rate of change of the current value of input is less than the current value of second predetermined value or input
Rate of change is more than third predetermined value " judged result be "No", the rate of change of the current value of input is more than or equal to the in other words
Two predetermined values are while less than or equal to third predetermined value, then judge the solar battery group string of input connection in normal work
State.Now, the rate of change of current value does not occur high level out-of-limit and low value is out-of-limit, i.e. input no current mutation, such as phase
The current value of adjacent or close input is all stable in a higher level, as the current value of the input is to be slowly reached
(not undergoing mutation), now judge input connection solar battery group string working properly.Such as time-division at noon, light
According to most strong, now all 1.5A of the current value of all adjacent or close inputs of one-level header box Z1-H1, but this high electricity
Stream was slowly reached from morning to noon, or even the electric current value stabilization of a period of time interior input, in 1.5A, changes at noon
Rate is zero, now thinks that the reason for causing this phenomenon is that solar irradiation condition is good, should not report fault, and should judge solar energy
Battery pack string is in normal operating conditions, so as to reduce cailure rate of false positives.
And if as it was previously stated, judged that in S4 step high level is out-of-limit or low value is out-of-limit, i.e., " defeated in S4 step
Enter end current value rate of change less than the current value of second predetermined value or input rate of change more than third predetermined value " sentence
Disconnected result is "Yes", then also there are two kinds of situations:
The first situation, the rate of change of current value there occurs that low value is out-of-limit.But, the rate of change of current value there occurs low value
Out-of-limit not necessarily representing occurs in that fault, because when solar battery group start of string enters shadow occlusion or cloud is sailed,
The solar battery group string being blocked is it can also happen that low value is out-of-limit.Therefore embodiment adds S5 step adjacent or close
Input is verified, and checking procedure is:Preset a fan-in k1 (k1 >=2), when there is k1 adjacent in same header box or
Close input is prescribed a time limit while occurring low value to get over, and still judges that solar battery group string is working properly, not outputting alarm signal.
That is, for some input, if the input occurs low value out-of-limit, while being adjacent or close one
Individual or multiple inputs also there occurs that low value is out-of-limit, then it is assumed that be multiple adjacent or close solar battery group strings while opening
Begin shadow occlusion is entered, now still judge that solar battery group string is working properly (because multiple sun of same header box
Energy battery pack string is while the possibility of open circuit is minimum), otherwise the low value is more limited to exception.
Second situation, the rate of change of current value there occurs that high level is out-of-limit.But, the rate of change of current value there occurs height
Out-of-limit not the necessarily representing of value occurs in that fault, because with the change of sun irradiation angle, solar battery group start of string leaves
When shadow of object is blocked or cloud has floatd, the solar battery group string that is blocked it can also happen that high level is out-of-limit, therefore
Embodiment adds the adjacent or close input of S5 step is verified, checking procedure is:A default fan-in k2 (k2 >=
2), when having k2 adjacent or close input in same header box while occurring high level more in limited time, still judge solar energy
Battery pack string is working properly, not outputting alarm signal.That is, for some input, if the input is sent out
Raw high level is out-of-limit, while being adjacent or one or more close input also there occurs that high level is out-of-limit, then it is assumed that be light
Causing multiple adjacent or close solar battery group strings while leaving shadow occlusion according to condition change, now still judging too
Sun energy battery pack string is working properly, and otherwise the high level is more limited to exception.
That is, judging in step in S5:If the rate of change of the current value of input is less than second predetermined value, judge
The rate of change of the current value of adjacent or close one or more of the other input is again smaller than the second predetermined value, such as
Fruit judged result is "Yes", then it is assumed that these adjacent or close solar battery group strings start simultaneously at entrance building effects
Block, now still judge the solar battery group string of the input connection in normal operating conditions;Or if input
Current value rate of change be more than third predetermined value, judge whether the electricity of adjacent or close one or more of the other input
The rate of change of flow valuve also greater than third predetermined value, if it is judged that be "Yes", then it is assumed that these adjacent or close solar energy
Battery pack string have left shadow occlusion simultaneously, now still judge that the solar battery group string of the input connection or upper level converge
Stream case is in normal operating conditions.Only when above-mentioned judged result is "No", i.e., only single input occurs high level to get over
Limit or low value more in limited time, just judge the solar battery group string of the input connection in abnormal operation.This just excludes
As dusk illumination variation, the building effects for As time goes on occurring block the dry of the environmental factors such as range
Disturb, reduce cailure rate of false positives further, improve fault recall rate.
Knowable to foregoing description, in the average of S2 step judges, by the solar battery group of actual for each input connection
The solar battery group string number of the actual connection of string number and this header box is included and considers scope and carry out the first time detection of fault,
Then the out-of-limit determination methods of the out-of-limit and low value of high level in S4, S5 step are recycled to detect the rate of change of current value, such as
In fruit S4 step, testing result is no, then can screen out the interference of environmental factor for the first time, reduces cailure rate of false positives, and if S4
In step, testing result is yes, then recycle the verification of the adjacent or close input in S5 step, to carry out the to fault
Secondary detection and screen out for the second time, therefore the accuracy of fault detect is greatly enhanced.
After working condition judgement is completed, the solar battery group string if there are input connection is in abnormal work shape
State, then alerted.
The header box of higher level is carried out confluxing detection the step of, the determination methods that adopted with to one-level header box
Z1-H1, two grades of header box Z1 carry out confluxing detection the step of and method essentially identical, differ only in and belong to two grades when input
During header box, sense, calculate and object is judged for one-level header box or solar battery group string, and work as input and belong to three-level remittance
During stream case, sense, calculate and object is judged for two grades of header boxs or solar battery group string, and need according to three-level header box
The actual connection of each input again each predetermined value is set respectively.
For example, the shown in FIG all inputs 1 of two grades of header box Z1 to input m be all connected be one-level converge
Stream case, but actually also two grades of header box Z1 only one of which of presence or multiple inputs are connected with one-level header box, and other
The situation (listed situation in such as table 1) that input is directly connect with solar battery group series winding.Although now to two grades of header boxs
The sensing current value that carried out to input m of each input 1, the rate of change of calculating current value, the out-of-limit judgement of high level, low value get over
Limit judges, and and null value judges and warning is all identical with one-level header box, but, when input m in two grades of header boxs is connected
During for one-level header box Z1-Hm, the sensing current value of this input m is the output current value of the output end of one-level header box
im, i.e., now the sensing current value of the input is the output current value of one-level header box rather than a certain solar battery group string
Output current value, this is possible to cause, in each input of two grades of header box Z1, had both existed and had come from one-level header box
Electric current, there is also the electric current for arising directly from solar battery group string, or the electricity of all inputs of two grades of header box Z1
Stream is the output current value of one-level header box.Even if in normal operation, the electric current of each input of two grades of header boxs
Value and its rate of change are also possible to differ greatly, it is therefore desirable to according to the actual connection of two grades of header boxs, when carrying out null value
During judgement, need the second predetermined value to the input of two grades of header box Z1 and third predetermined value to be set respectively, and need
When carrying out the out-of-limit judgement of low value and the out-of-limit judgement of high level, need to set second predetermined value and third predetermined value respectively again,
Or when carrying out average to three-level header box and judging, first predetermined value, second predetermined value and third predetermined value are set respectively.
The like to N level header box (N >=2), according to the difference of header box rank, need the header box for the rank
The actual connection of each input set first predetermined value respectively, or while set second predetermined value and the 3rd pre- respectively
Definite value.Certainly, the predetermined value that these set respectively might not be different.For example, when all inputs of one-level header box connect
Solar battery group string all same, all inputs of two grades of header boxs be all connected with these identical one-level header box, three-levels
All inputs of header box are all connected with two grades of header boxs of identical, now converge for one-level header box, two grades of header boxs, three-levels
Stream case carry out confluxing detection when set first predetermined value can be identical.
When further by the present embodiment compared with prior art, only to detect to one-level header box, its header box
What each input connected is solar battery group string, as a example by each input electric current is single solar battery group string electric current:
1) the out-of-limit comparison of low value
Prior art detection method:Daily afternoon or the morning or winter sunlight irradiation angular deviation larger when
Wait, as the arrangement of photovoltaic array is different, the solar battery group string for some positions very likely starts by surrounding buildingses
Thing is blocked, and the solar battery group string electric current being at this moment blocked will be significantly less than other sun for around accessing same header box
Can battery pack string electric current, at this moment solar battery group string be in normal operating conditions, but prior art will be at these
Input judges to be out of order, and wrong report situation occurs.
The present embodiment method:By the verification of adjacent or close input, can effectively solve the problem that art methods not
Foot, effectively reduces the wrong report caused by building is blocked, will the effectively lifting 50% of alarm accuracy rate.
2) the out-of-limit comparison of high level
Prior art shortcoming:When daily afternoon or the morning or winter sunlight irradiation angular deviation are larger, by
Arrangement in photovoltaic array is different, and the solar battery group string for some positions very likely initially moves off Adjacent Buildings screening
Gear, the solar battery group string electric current not at this moment being blocked will be significantly greater than other solar energy that surrounding accesses same header box
Battery pack string electric current, at this moment solar battery group string be in normal operating conditions, but prior art will be defeated at these
Enter and hold judgement to be out of order, wrong report situation occur.
The present embodiment method:Judgement out-of-limit with low value is similar, effectively can be subtracted by the verification of adjacent or close input
Few wrong report caused by building is blocked, will the effectively lifting 50% of alarm accuracy rate.
Three-level header box ... the N level header box confluxed for N level in array, the above-mentioned method of inspection are still effective.
Comprehensive case above, no matter in solar power station, how photovoltaic array arranges, and the method for the present embodiment can be transferred through
Adjusting parameter, realizes the effective monitoring to photovoltaic array, reduces cailure rate of false positives, improves fault recall rate.
With reference to Fig. 3, the detecting system of confluxing adopted by the solar power station in Fig. 1 is the figure shows.The detection system of confluxing
System includes:
Current sensing unit, for sensing the current value of each input of the header boxs at different levels in Fig. 1, and will be measured
Current value sends data processing unit to.Current sensing unit can carry out current-mode by configuring Hall element or current transformer
The collection of analog quantity.Current sensing unit (Hall element/current transformer) quantity can carry out flexible configuration according to different requirements, with
When acquisition precision according to the different components and parts for requiring to configure different accuracies, so as to preferably improve product cost.It is preferred that Hall
Element is used as the acquisition elements of current sensing unit.
Data processing unit, for calculating the rate of change of the current value of each input.
Judging unit, for according to the current value of each input and/or the rate of change of current value come to solar battery group
Whether string or upper level header box are judged in normal operating conditions.Data processing unit and judging unit are on hardware
Mainly it is made up of CPU processing unit and memory cell, the data processing of each detection module of header box is realized, the work(such as data storage
Can, the different program of programming can be required according to difference in addition, programming program can Local or Remote carry out, program parameter etc. can pass through
Communication module carries out remotely located, convenient use.CPU processing unit can be by the chip with data processing function or integrated circuit
Composition, preferably uses single-chip microcomputer C8051F021 as core CPU unit.Memory cell includes ROM and RAM, wherein external storage
Device can according to need configure different capabilities memory.Judging unit judges step for executing foregoing S2, S4, S5.
In addition to above-mentioned functions unit, the system of the present embodiment can also further include following any one or more units
Module:
Alarm Unit:For judging the solar battery group string for having input connection or upper level header box in judging unit
After abnormal operation, alerted.
Power module:Mainly high voltage is achieved to the conversion of low-voltage using DC DC principle, and as inspection of confluxing
Survey the governor circuits such as module, communication module and working power is provided.Preferably, power module electric energy can be directly from photovoltaic array
In header box, without the need for external power supply, convenient construction, using simple, greatly simplify system design, and power module power consumption
Less, do not affect photovoltaic array whole efficiency.Stress levels 1000V are preferably used, such as 800-400V is defeated for wide range input voltage
Enter, the DC-DC power module of 24V/5v output.In practice, it is also possible to which the power module using independent power supply is come for inspection of confluxing
Current sensing unit in examining system etc. is powered.
Voltage acquisition unit:For carrying out the real-time of voltage to the input of the header boxs at different levels in Fig. 1 or output end
Gathering, and the voltage of collection is sent to data processing unit carries out Correlation method for data processing.Correspondingly, data acquisition unit can
The input/output power of header boxs at different levels is calculated with the magnitude of voltage that transmitted according to voltage acquisition unit.Judging unit is permissible
Whether whether header box is judged within a predetermined range in normal operating conditions according to input/input power, if voltage or power
Value then judges input exception beyond preset range.
Communication module:For being transmitted to the data of the header box in photovoltaic array in real time, such as by data processing list
First rate of change for being calculated the current value for obtaining, power, alarm signal etc. are transmitted to Surveillance center, it is achieved that header box and monitoring
The communication of the external equipments such as the PC at center.Different communications can be configured according to user's requirement and the difference of actually used situation
Module, realizes being wirelessly transferred or wire transmission, and bigger is user-friendly to.Communication mode can set, such as using wire communication,
485 communication modes, standard MODBUS agreement are transmitted.
DC lightning prevention module:The position of lightning protection is needed installed in header box, PC of Surveillance center etc., for header box
Carry out lightning protection.As the solar battery group string in photovoltaic array, header box etc. are used for open air, therefore configuring direct current is prevented
Thunder module realizes lightning protection.DC lightning prevention module is electricity piece commonly used in the art, and concrete structure is no longer described in detail herein.
Breaker:Coupled to header box, judging unit judges solar battery group string or the upper level for having input connection
After abnormal operation, triggering breaker disconnects header box.Circuit breaker voltage grade is preferably able to reach 1000V, electric current
Grade is determined according to the input sum that solar panel current parameters and header box are accessed.
Fuse:Be connected between the solar panel of solar battery group string, solar battery group string and header box
Input between, the input of the output end of upper level header box and next stage header box, the output end of N level header box with inverse
Become between device etc. and the position of excessively stream is susceptible to, for protecting the electronics from the harm of overcurrent, if being not added with protection, this
Overcurrent be likely to result in electronic device failure, overheated, damage even on fire.If fuse grade is excessive, it is impossible to provide guarantor
Protective function, if too small, cannot normal work.Therefore, when fuse is selected, the class rating according to photovoltaic array is needed
And depending on relevant criterion is required.The minimum level of fuse can be obtained by the calculation of short-circuit current of circuit in photovoltaic array, such as
Fruit local standard does not have particular/special requirement, and the fuse for preferably using and the rated value of wiring need to meet minimum 1.56 times Isc
(short circuit current) value.Fuse is electricity piece commonly used in the art, no longer its structure is described in detail herein.
Counnter attack diode:For preferably route protection being realized, counnter attack can be concatenated in each road solar battery group string
Diode.
If it is desired, can also match other analog acquisition units, such as temperature, humidity etc..
Although the present invention is described with reference to above example, the present invention is not limited to above-described embodiment, and
Only limited by claim, those of ordinary skill in the art easily can modify to which and change, but and without departing from
The essential idea of the present invention and scope.