CN107994866B - Method, apparatus, equipment and the storage medium of direct current arc fault detection - Google Patents
Method, apparatus, equipment and the storage medium of direct current arc fault detection Download PDFInfo
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02S—GENERATION OF ELECTRIC POWER BY CONVERSION OF INFRARED RADIATION, VISIBLE LIGHT OR ULTRAVIOLET LIGHT, e.g. USING PHOTOVOLTAIC [PV] MODULES
- H02S50/00—Monitoring or testing of PV systems, e.g. load balancing or fault identification
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Abstract
The invention discloses method, apparatus, equipment and the computer readable storage mediums of a kind of detection of direct current arc fault, it include: in the current signal of photovoltaic system gathered in advance, choose the first predetermined number continuous sampling point carry out fast Fourier analysis, so as to obtain the continuous sampling point spectral magnitude square；Extract the fast Fourier analysis in pre-selection frequency range as a result, and the pre-selection frequency range is divided into the frequency sub-band of the second predetermined number, seek spectrum energy of the quadratic sum of the spectral magnitude of all continuous sampling points in each frequency sub-band as each frequency sub-band；According to the default weight coefficient and the spectrum energy of each frequency sub-band, Weighted spectral energy is sought；According to the Weighted spectral energy and the comparison result of default spectrum energy threshold value, judge whether the photovoltaic system generates direct current arc fault.Method, apparatus, equipment and computer readable storage medium provided by the present invention improve the precision of photovoltaic system direct current arc fault detection.
Description
Technical field
The present invention relates to technical field of photovoltaic power generation, the method, apparatus detected more particularly to a kind of direct current arc fault,
Equipment and computer readable storage medium.
Background technique
With the rapid growth of photovoltaic industry, safety problem caused by photovoltaic system direct current arc fault receives people's
Extensive concern.
The direct current arc fault of photovoltaic system detects the inspection mainly using the variation characteristic of arc current as judgment basis at present
Survey method can be divided into method of time domain characteristics and two kinds of frequency domain character method.Temporal signatures detection method mainly passes through the change of analysis arc current
Law judges arc fault, with simple, the easy to accomplish advantage of algorithm, but it is more in the presence of detection disturbing factor, low precision
Disadvantage.Frequency domain character detection method mainly concentrates harmonic content or frequency spectrum in frequency band (40kHz-100kHz) for arc current
Energy extracts, and threshold value is arranged and carries out arc fault judgement, compared with temporal signatures detection method, frequency domain character detection method
Reliability it is preferable, precision is higher, but the noise jamming vulnerable to inverter or other devices, and there are still erroneous judgements and the feelings of missing inspection
Condition.In order to improve detection accuracy, some documents introduce the methods of wavelet transformation and neural network, but the complexity of algorithm also with
Raising, it can be achieved that property is lower.
In summary as can be seen that how to improve photovoltaic system direct current arc fault detection precision be have at present it is to be solved
The problem of.
Summary of the invention
The object of the present invention is to provide a kind of method, apparatus of direct current arc fault detection, equipment and computer-readable
Storage medium has solved the problems, such as that photovoltaic system direct current arc fault detection accuracy is lower in the prior art.
In order to solve the above technical problems, the present invention provides a kind of method of direct current arc fault detection, comprising: adopted in advance
In the current signal of the photovoltaic system of collection, the continuous sampling point for choosing the first predetermined number carries out fast Fourier analysis, so as to
Obtain square of the spectral magnitude of the continuous sampling point；The fast Fourier analysis in pre-selection frequency range is extracted as a result, and by institute
The frequency sub-band that pre-selection frequency range is divided into the second predetermined number is stated, the spectral magnitude of all continuous sampling points in each frequency sub-band is sought
Spectrum energy of the quadratic sum as each frequency sub-band；According to the default weight coefficient and the spectrum energy of each frequency sub-band,
Seek Weighted spectral energy；According to the Weighted spectral energy and the comparison result of default spectrum energy threshold value, described in judgement
Whether photovoltaic system generates direct current arc fault.
It is preferably, described that the pre-selection frequency range is divided into the frequency sub-band of the second predetermined number includes: in the pre- frequency-selecting
Times frequency point that the switching frequency of the photovoltaic system is searched in section removes the fast of frequency range around times frequency point according to preset condition
After fast Fourier analysis result, the pre-selection frequency range is divided into the frequency sub-band of the second predetermined number.
Preferably, the default process of the default weight coefficient of each frequency sub-band includes: according to the photovoltaic system just
Changing value and preset condition under normal operating status with the spectrum energy of each frequency sub-band under arc fault state obtain described each
The initial value of the weight coefficient of frequency sub-band；Changing value according to the spectrum energy for presetting adaptive condition and each frequency sub-band
The initial value of the weight coefficient is adaptively adjusted, adaptive weighting coefficient is obtained.
Preferably, as the spectrum energy changing value Δ E of each frequency sub-bandfj(j=1,2 ..., m+1) it is more than frequency spectrum
When the frequency sub-band number of energy variation threshold value is no more than (m+1)/3, the initial value of the weight coefficient is adaptively adjusted, and described
The initial value of weight coefficient meets Kf1(0)+Kf2(0)+...+Kf(m+1), and K (0)=1fj(0) > 0 (j=1,2 ..., m+
1)；
Utilize the weight coefficient K of j-th of frequency sub-band of t momentfj(t) with the weight coefficient mistake of j-th of frequency sub-band of the t moment
Cheng Bianliang K'fj(t) relationship seeks Kfj(t)；
Enable the process variable K' of the weight coefficient of t moment m-th frequency sub-bandfMIt (t) is all frequency sub-band weight coefficient processes
Variable K'fj(t) minimum value, it may be assumed that
K'fM(t)=min (K'f1(t),K'f2(t),...,K'f(m+1)(t)), (1≤M≤m+1), if K'fM(t) >=0, then
Kfj(t)=K'fj(t), if K'fM(t) 0 <, then Kfj(t) and K'fj(t) relationship are as follows:
Wherein, K'fj(t)=Kfj(t-1)-ΔKfj；
For KE1,KE2,......,KE(m+1)Average value, Δ EfSpectrum energy for the pre-selection frequency range changes total amount,
ΔEf=Kf1(t-1)|ΔEf1|+Kf2(t-1)|ΔEf2|+...+Kf(m+1)(t-1)|ΔEf(m+1)|, G is weight adjustment factor, Ef
For the spectral magnitude weighted sum of squares of all frequency sub-band, Ef=Kf1(t-1)Ef1+Kf2(t-1)Ef2+...+Kf(m+1)(t-1)Ef(m+1)
(j=1,2 ..., m+1), wherein Efj(j=1,2 ..., m+1) is square of all spectral magnitudes in each frequency sub-band
With.
It preferably, further include that the light is judged according to the variance of the current signal and default variance threshold values comparison result
Whether volt system generates direct current arc fault.
It is preferably, described that judge whether the photovoltaic system generates direct current arc fault include: the Weighted spectral energy
It is more than or equal to the default variance threshold values more than or equal to the default spectrum energy threshold value and/or the variance of the current signal
When, then the photovoltaic system generates direct current arc fault.
The present invention also provides a kind of devices of direct current arc fault detection, comprising:
Sampled point analysis module, for choosing the first predetermined number in the current signal of photovoltaic system gathered in advance
Continuous sampling point carry out fast Fourier analysis, so as to obtain the continuous sampling point spectral magnitude square；
Frequency range division module, for extracting the fast Fourier analysis in pre-selection frequency range as a result, and by the pre-selection frequency range
It is divided into the frequency sub-band of the second predetermined number, seeks the quadratic sum conduct of the spectral magnitude of all continuous sampling points in each frequency sub-band
The spectrum energy of each frequency sub-band；
Weighting block seeks Weighted spectral for the default weight coefficient and the spectrum energy according to each frequency sub-band
Energy；
Frequency domain judgment module, for the comparison result according to the Weighted spectral energy and default spectrum energy threshold value,
Judge whether the photovoltaic system generates direct current arc fault.
Preferably, further includes: time domain judgment module, for according to the variance of the current signal and default variance threshold values ratio
Compared with as a result, judging whether the photovoltaic system generates direct current arc fault.
The present invention also provides a kind of equipment of direct current arc fault detection, comprising: memory, for storing computer journey
Sequence；Processor, the step of a kind of method of above-mentioned direct current arc fault detection is realized when for executing the computer program.
The present invention also provides a kind of computer readable storage mediums, which is characterized in that the computer-readable storage medium
Computer program is stored in matter, the computer program realizes a kind of above-mentioned direct current arc fault detection when being executed by processor
Method the step of.
Method, apparatus, equipment and the computer-readable storage of a kind of direct current arc fault detection provided by the present invention
Medium, after having carried out fast Fourier analysis to the continuous sampling point in the current signal of collected photovoltaic generating system；It will
The frequency band for taking arc current mainly to concentrate in sampled signal is divided into the frequency sub-band of predetermined number, then seeks each height frequency respectively
The spectrum energy of section, i.e., the quadratic sum of all spectral magnitudes in described each frequency sub-band；It is each height according to preset rules
After the spectrum energy setting weight coefficient of frequency range, the Weighted spectral energy of pre-selection frequency range is sought；By the Weighted spectral energy with
The threshold value of default spectrum energy is compared, and judges whether photovoltaic system occurs direct current arc fault.According to the above method, dress
It sets, equipment and computer readable storage medium, when carrying out the fault detection of direct current scratch start, to arc current frequency-domain spectrum energy
Weighted band-wise processing is carried out, interference of the photovoltaic generating system operating status variation to detection is reduced, reduces the wind of erroneous detection
Danger improves the precision of photovoltaic system direct current arc fault detection.
Detailed description of the invention
It, below will be to embodiment or existing for the clearer technical solution for illustrating the embodiment of the present invention or the prior art
Attached drawing needed in technical description is briefly described, it should be apparent that, the accompanying drawings in the following description is only this hair
Bright some embodiments for those of ordinary skill in the art without creative efforts, can be with root
Other attached drawings are obtained according to these attached drawings.
Fig. 1 is the flow chart of the first specific embodiment of the method for direct current arc fault provided by the present invention detection；
Fig. 2 is the flow chart of second of specific embodiment of the method for direct current arc fault provided by the present invention detection；
Fig. 3 is a kind of structural block diagram of the device of direct current arc fault detection provided in an embodiment of the present invention.
Specific embodiment
Core of the invention is to provide the method, apparatus of direct current arc fault detection a kind of, equipment and computer-readable
Storage medium improves the precision of photovoltaic system direct current arc fault detection.
In order to enable those skilled in the art to better understand the solution of the present invention, with reference to the accompanying drawings and detailed description
The present invention is described in further detail.Obviously, described embodiments are only a part of the embodiments of the present invention, rather than
Whole embodiments.Based on the embodiments of the present invention, those of ordinary skill in the art are not making creative work premise
Under every other embodiment obtained, shall fall within the protection scope of the present invention.
Referring to FIG. 1, Fig. 1 is the first specific embodiment of the method for direct current arc fault provided by the present invention detection
Flow chart；Specific steps are as follows:
Step S101: in the current signal of photovoltaic system gathered in advance, the continuous sampling of the first predetermined number is chosen
Point carry out fast Fourier analysis, so as to obtain the continuous sampling point spectral magnitude square；
The DC current of photovoltaic generating system is sampled with the sample frequency more than or equal to 200kHz, and takes N number of company
Continuous sampled point Ix (x=1,2 ..., N).Fast Fourier (FFT) analysis is carried out to Ix (x=1,2 ..., N)；Seek electric arc electricity
Flow the real part of the fft analysis result in the frequency band (40kHz-100kHz) mainly concentrated and the quadratic sum of imaginary part, i.e. frequency spectrum width
Square of value.
Step S102: extracting the fast Fourier analysis in pre-selection frequency range as a result, and the pre-selection frequency range is divided into the
The frequency sub-band of two predetermined numbers seeks the quadratic sum of the spectral magnitude of all continuous sampling points in each frequency sub-band as each son
The spectrum energy of frequency range；
Step S103: according to the default weight coefficient and the spectrum energy of each frequency sub-band, Weighted spectral energy is sought；
Step S104: according to the Weighted spectral energy and the comparison result of default spectrum energy threshold value, described in judgement
Whether photovoltaic system generates direct current arc fault.
This specific embodiment has carried out frequency-division section to arc current spectrum energy and has added under the premise of not introducing complicated algorithm
Power processing, reduces the photovoltaic generating system influence that Self-variation detects direct current arc fault under operation, improves straight
Flow the precision and reliability of arc fault detection.
Referring to FIG. 2, Fig. 2 is second of specific embodiment of the method for direct current arc fault provided by the present invention detection
Flow chart.
On the basis of above-mentioned specific embodiment, embodiment adds removal pre-selection frequency range in by photovoltaic generating system from
Body interferes the operation of the analysis result of the FFT of frequency range around biggish switch frequency domain times frequency point, further reduced the wind of erroneous detection
Danger.In addition, also adding the operation adaptively adjusted to the weight coefficient of each frequency sub-band, and introduce the judgement of time domain variance
As the supplement criterion of supplement fault detection, the risk of missing inspection is reduced.
The present embodiment specific steps are as follows:
Step S201: N number of continuous sampling point Ix (x=1,2 ..., N) is chosen in the arc current of acquisition, to Ix (x=
1,2 ..., N) carry out fft analysis；
Step S202: the switching frequency f of photovoltaic generating system is removedsAll times of frequency points in 40kHz-100kHz frequency range
Surrounding frequency range Δ fiFft analysis result；
The switching frequency f of photovoltaic generating system is found out in 40kHz-100kHz frequency rangesAll times of frequency point K1·fs,
K2·fs,...,Km·fs, wherein K1,K2,...,KmIn be positive integer.
Step S203: the frequency range of 40kHz-100kHz is divided into m+1 sections: (40kHZ, K1·fs-Δf1)、(K1·fs+Δ
f1, K2·fs-Δf2)、(K2·fs+Δf2, K3·fs-Δf3)、…、(Km·fs+Δfm, 100kHZ)；
The Δ fi(i=1,2 ..., m) situation decision can be analyzed according to actual spectrum.
Step S204: seeking square of the spectral magnitude of all continuous sampling points in each sub- frequency band, i.e., each son frequency
The spectrum energy of section；
Step S205: being respectively filtered each frequency sub-band, and the biggish point of spectral magnitude square is replaced with the frequency range
The minimum value of interior spectral magnitude square；
Step S206: according to the photovoltaic system frequency with each frequency sub-band under arc fault state under normal operating conditions
The changing value Δ E of spectrum energyfj(j=1,2 ..., m+1), obtain the initial value of the weight coefficient of each frequency sub-band；
The initial value of the weight coefficient of each frequency sub-band meets Kf1(0)+Kf2(0)+...+Kf(m+1), and K (0)=1fj
(0) > 0 (j=1,2 ..., m+1).
Step S207: as the spectrum energy changing value Δ E of each frequency sub-bandfj(j=1,2 ..., m+1) it is more than frequency
When the frequency sub-band number of spectrum energy change threshold is no more than (m+1) 3, the initial value of the weight coefficient is adaptively adjusted, is obtained
Adaptive weighted coefficient；
As the spectrum energy changing value Δ E of each frequency sub-bandfj(j=1,2 ..., m+1) it is more than that spectrum energy changes
When the frequency sub-band number of threshold value is no more than (m+1) 3, it is believed that the reason of causing spectrum energy to change is photovoltaic generating system itself fortune
Row state change, rather than direct current arc fault can change according to each band energy be adjusted to weight coefficient at this time, so that power
Weight coefficient preferably adapts to photovoltaic generating system, and photovoltaic generating system Self-variation is avoided to cause direct current arc fault erroneous detection.
The current time weight coefficient process variable K' of current t momentfjIt (t) can be by the weight coefficient K of last momentfj(t-
1) the variation delta K of weight coefficient is subtractedfjIt obtains, i.e. K'fj(t)=Kfj(t-1)-ΔKfj, wherein t is the integer greater than 0, power
Weight index variation amount Δ KfjCalculation formula it is as follows:
Wherein, KEj=Δ Efj/Efj(j=1,2 ..., m+1)；For KE1,KE2,......,KE(m+1)Be averaged
Value, Δ EfSpectrum energy for the pre-selection frequency range changes total amount, Δ Ef=Kf1(t-1)|ΔEf1|+Kf2(t-1)|ΔEf2|
+...+Kf(m+1)(t-1)|ΔEf(m+1)|；G is weight adjustment factor, can be given according to the actual situation, can use fixed value or function；
EfFor the spectral magnitude weighted sum of squares of all frequency sub-band, Ef=Kf1(t-1)Ef1+Kf2(t-1)Ef2+...+Kf(m+1)(t-1)
Ef(m+1)(j=1,2 ..., m+1).
Due to Δ Kf1+ΔKf2+...+ΔKf(m+1)=0, K' can be obtainedf1(t)+K'f2(t)+...+K'f(m+1)(t)=1.
To avoid Kfj(t) 0 < is needed to K'fj(t) it is further processed, enables M (1≤M≤m+1) a frequency sub-band
Weight coefficient process variable K'fMIt (t) is all frequency sub-band weight coefficient process variable K'fj(t) minimum value, it may be assumed that K'fM(t)=
min(K'f1(t),K'f2(t),...,K'f(m+1)(t)),(1≤M≤m+1).If K'fM(t) >=0, then Kfj(t)=K'fj(t), if
K'fM(t) 0 <, then Kfj(t) and K'fj(t) relationship are as follows:
K at this timef1(t)+Kf2(t)+...+Kf(m+1)(t)=K'f1(t)+K'f2(t)+...+K'f(m+1)It (t)=1, can be true
The sum for protecting weight coefficient is always 1.
Step S208: according to the weight coefficient and spectrum energy of each frequency range, the Weighted spectral energy of total frequency range is sought；
According to the weight coefficient of each frequency range, the Weighted spectral ENERGY E of total frequency range is soughtf=Kf1(t)Ef1+Kf2(t)Ef2+...
+Kf(m+1)(t)Ef(m+1)(j=1,2 ..., m+1), wherein Efj(j=1,2 ..., m+1) it is all frequency spectrums in each frequency sub-band
The quadratic sum of amplitude.
Step S209: with default spectrum energy threshold value comparison, judge whether the photovoltaic generating system generates direct-current arc
Failure；
Step S210: according to the variance of the current signal and default variance threshold values comparison result, judge the photovoltaic system
Whether system generates direct current arc fault.
The variance of DC current sampling can be acquired according to variance calculation formula are as follows:Wherein,
For the average value of Ix (x=1,2 ..., N).
WhenChange rateWhen smaller, it is believed that photovoltaic system is more stable, if direct current arc fault does not occur, DC current
More stable, the variance of sampled value is smaller；If direct current arc fault occurs, containing more higher hamonic wave in arc current, directly
The variance for flowing current sampling data is larger.The DC current sampled value variance (Is) of more stable system2With preset variance threshold values,
By (Is)2More than or equal to variance threshold values as the time-domain criteria for detecting direct current arc fault.
The Weighted spectral energy is more than or equal to the default spectrum energy threshold value and/or the variance of the current signal is big
When being equal to the default variance threshold values, then the photovoltaic system generates direct current arc fault.The direct current of photovoltaic generating system
When stream meets any criterion in frequency domain criterion and time-domain criteria, think to detect direct current arc fault, while being unsatisfactory for two
A condition then thinks that direct current arc fault does not occur.
This specific embodiment combines the temporal signatures and frequency domain character of arc current, removes light during frequency-domain analysis
The influence of higher hamonic wave near photovoltaic generating system switching frequency integral multiple, and the weighting coefficient of spectrum energy is carried out certainly in real time
Adjustment is adapted to, interference of system itself higher hamonic wave to arc fault detection is reduced, improves the precision of arc-detection；Together
When, this larger temporal signatures of variance of arc current reduce arc fault missing inspection as supplement criterion when system is stablized
Risk, improve the precision and reliability of detection, while complicated algorithm will not be introduced, realizability with higher.
Referring to FIG. 3, Fig. 3 is a kind of structural frames of the device of direct current arc fault detection provided in an embodiment of the present invention
Figure；Specific device may include:
Sampled point analysis module 100, in the current signal of photovoltaic system gathered in advance, choosing first default
Several continuous sampling point carries out fast Fourier analysis, so as to obtain the continuous sampling point spectral magnitude square；
Frequency range division module 200, for extracting the fast Fourier analysis in pre-selection frequency range as a result, and by the pre- frequency-selecting
Section is divided into the frequency sub-band of the second predetermined number, and the quadratic sum for seeking the spectral magnitude of all continuous sampling points in each frequency sub-band is made
For the spectrum energy of each frequency sub-band；
Weighting block 300 seeks weighting frequency for the default weight coefficient and the spectrum energy according to each frequency sub-band
Spectrum energy；
Frequency domain judgment module 400, for the comparison knot according to the Weighted spectral energy and default spectrum energy threshold value
Fruit, judges whether the photovoltaic system generates direct current arc fault.
The device of the DC current fault detection of the present embodiment for realizing DC current fault detection above-mentioned method,
Therefore the method for the visible DC current fault detection hereinbefore of specific embodiment in the device of DC current fault detection
Embodiment part, for example, sampled point analysis module 100, frequency range division module 200, weighting block 300, frequency domain judgment module
400, it is respectively used to step S101, S102, S103 and S104 in the method for realizing above-mentioned DC current fault detection, so,
Specific embodiment is referred to the description of corresponding various pieces embodiment, and details are not described herein.
The specific embodiment of the invention additionally provides a kind of equipment of direct current arc fault detection, comprising: memory, for depositing
Store up computer program；Processor realizes a kind of side of above-mentioned direct current arc fault detection when for executing the computer program
The step of method.
The specific embodiment of the invention additionally provides a kind of computer readable storage medium, which is characterized in that the computer
Computer program is stored on readable storage medium storing program for executing, the computer program realizes a kind of above-mentioned direct current when being executed by processor
The step of method of arc fault detection.
Each embodiment in this specification is described in a progressive manner, the highlights of each of the examples are with it is other
The difference of embodiment, same or similar part may refer to each other between each embodiment.For being filled disclosed in embodiment
For setting, since it is corresponded to the methods disclosed in the examples, so being described relatively simple, related place is referring to method part
Explanation.
Professional further appreciates that, unit described in conjunction with the examples disclosed in the embodiments of the present disclosure
And algorithm steps, can be realized with electronic hardware, computer software, or a combination of the two, in order to clearly demonstrate hardware and
The interchangeability of software generally describes each exemplary composition and step according to function in the above description.These
Function is implemented in hardware or software actually, the specific application and design constraint depending on technical solution.Profession
Technical staff can use different methods to achieve the described function each specific application, but this realization is not answered
Think beyond the scope of this invention.
The step of method described in conjunction with the examples disclosed in this document or algorithm, can directly be held with hardware, processor
The combination of capable software module or the two is implemented.Software module can be placed in random access memory (RAM), memory, read-only deposit
Reservoir (ROM), electrically programmable ROM, electrically erasable ROM, register, hard disk, moveable magnetic disc, CD-ROM or technology
In any other form of storage medium well known in field.
It to the method, apparatus of DC current fault detection provided by the present invention, equipment and computer-readable deposits above
Storage media is described in detail.It is used herein that a specific example illustrates the principle and implementation of the invention,
The above description of the embodiment is only used to help understand the method for the present invention and its core ideas.It should be pointed out that for this technology
For the those of ordinary skill in field, without departing from the principle of the present invention, several improvement can also be carried out to the present invention
And modification, these improvements and modifications also fall within the scope of protection of the claims of the present invention.
Claims (9)
1. a kind of method of direct current arc fault detection characterized by comprising
In the current signal of photovoltaic system gathered in advance, the continuous sampling point for choosing the first predetermined number is carried out in quick Fu
Leaf analysis, so as to obtain the continuous sampling point spectral magnitude square；
The fast Fourier analysis in pre-selection frequency range is extracted as a result, and the pre-selection frequency range is divided into the son of the second predetermined number
Frequency range seeks spectrum energy of the quadratic sum of the spectral magnitude of all continuous sampling points in each frequency sub-band as each frequency sub-band；
According to the default weight coefficient and the spectrum energy of each frequency sub-band, Weighted spectral energy is sought；Each frequency sub-band
The default process of default weight coefficient include: according to the photovoltaic system under normal operating conditions and under arc fault state
The changing value and preset condition of the spectrum energy of each frequency sub-band obtain the initial value of the weight coefficient of each frequency sub-band；According to
The initial value of the weight coefficient is carried out according to the changing value for the spectrum energy for presetting adaptive condition and each frequency sub-band
Adaptive adjustment, obtains adaptive weighting coefficient；
According to the Weighted spectral energy and the comparison result of default spectrum energy threshold value, judge whether the photovoltaic system produces
Raw direct current arc fault.
2. the method as described in claim 1, which is characterized in that described that the pre-selection frequency range is divided into the second predetermined number
Frequency sub-band includes:
Times frequency point that the switching frequency of the photovoltaic system is searched in the pre-selection frequency range, according to described times of preset condition removal
Around frequency point after the fast Fourier analysis result of frequency range, the pre-selection frequency range is divided into the frequency sub-band of the second predetermined number.
3. the method as described in claim 1, which is characterized in that the foundation presets adaptive condition and each frequency sub-band
The changing value of spectrum energy the initial value of the weight coefficient is adaptively adjusted, obtain adaptive weighting coefficient packet
It includes:
As the spectrum energy changing value Δ E of each frequency sub-bandfj(j=1,2 ..., m+1) it is more than spectrum energy change threshold
Frequency sub-band number when being no more than (m+1)/3, adaptively adjust the initial value of the weight coefficient, and the weight coefficient just
Initial value meets
Kf1(0)+Kf2(0)+...+Kf(m+1), and K (0)=1fj(0) > 0 (j=1,2 ..., m+1)；
Utilize the weight coefficient K of j-th of frequency sub-band of t momentfj(t) become with the weight coefficient process of j-th of frequency sub-band of the t moment
Measure K'fj(t) relationship seeks Kfj(t)；
Enable the weight coefficient process variable K' of t moment m-th frequency sub-bandfMIt (t) is all frequency sub-band weight coefficient process variable K'fj
(t) minimum value, it may be assumed that
K'fM(t)=min (K'f1(t),K'f2(t),…,K'f(m+1)(t)), (1≤M≤m+1), if K'fM(t) >=0, then
Kfj(t)=K'fj(t), if K'fM(t) 0 <, then Kfj(t) and K'fj(t) relationship are as follows:
Wherein K'fj(t)=Kfj(t-1)-ΔKfj；
For KE1,KE2,……,KE(m+1)Average value, Δ EfSpectrum energy for the pre-selection frequency range changes total amount, Δ Ef=
Kf1(t-1)|ΔEf1|+Kf2(t-1)|ΔEf2|+…+Kf(m+1)(t-1)|ΔEf(m+1)|, G is weight adjustment factor, EfIt is all
The spectral magnitude weighted sum of squares of frequency sub-band,
Ef=Kf1(t-1)Ef1+Kf2(t-1)Ef2+…+Kf(m+1)(t-1)Ef(m+1)(j=1,2 ... ..., m+1), wherein
Efj(j=1,2 ..., m+1) is the quadratic sum of all spectral magnitudes in each frequency sub-band.
4. method as described in any one of claims 1 to 3, which is characterized in that further include:
According to the variance of the current signal and default variance threshold values comparison result, judge whether the photovoltaic system generates direct current
Arc fault.
5. method as claimed in claim 4, which is characterized in that described to judge whether the photovoltaic system generates direct-current arc event
Barrier includes:
The variance that the Weighted spectral energy is more than or equal to the default spectrum energy threshold value and/or the current signal is greater than etc.
When the default variance threshold values, then the photovoltaic system generates direct current arc fault.
6. a kind of device of direct current arc fault detection characterized by comprising
Sampled point analysis module, for choosing the company of the first predetermined number in the current signal of photovoltaic system gathered in advance
Continuous sampled point carries out fast Fourier analysis, so as to obtain the continuous sampling point spectral magnitude square；
Frequency range division module, for extracting the fast Fourier analysis in pre-selection frequency range as a result, and dividing the pre-selection frequency range
For the frequency sub-band of the second predetermined number, the quadratic sum of the spectral magnitude of all continuous sampling points in each frequency sub-band is sought as each son
The spectrum energy of frequency range；
Weighting block seeks Weighted spectral energy for the default weight coefficient and the spectrum energy according to each frequency sub-band；
The default process of the default weight coefficient of each frequency sub-band include: according to the photovoltaic system under normal operating conditions with electricity
The changing value and preset condition of the spectrum energy of each frequency sub-band under arc malfunction obtain the weight coefficient of each frequency sub-band
Initial value；Changing value according to the spectrum energy for presetting adaptive condition and each frequency sub-band is to the weight coefficient
Initial value is adaptively adjusted, and adaptive weighting coefficient is obtained；
Frequency domain judgment module, for the comparison result according to the Weighted spectral energy and default spectrum energy threshold value, judgement
Whether the photovoltaic system generates direct current arc fault.
7. device as claimed in claim 6, which is characterized in that further include: time domain judgment module, for being believed according to the electric current
Number variance and default variance threshold values comparison result, judge whether the photovoltaic system generates direct current arc fault.
8. a kind of equipment of direct current arc fault detection characterized by comprising
Memory, for storing computer program；
Processor realizes a kind of direct-current arc event as described in any one of claim 1 to 5 when for executing the computer program
The step of hindering the method for detection.
9. a kind of computer readable storage medium, which is characterized in that be stored with computer on the computer readable storage medium
Program realizes a kind of direct current arc fault as described in any one of claim 1 to 5 when the computer program is executed by processor
The step of method of detection.
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| US10985695B2 (en) * | 2018-08-28 | 2021-04-20 | Analog Devices International Unlimited Company | DC arc detection and photovoltaic plant profiling system |
| CN109239558B (en) * | 2018-11-08 | 2020-10-02 | 重庆大学 | Direct current fault arc detection and protection device |
| CN109342904B (en) * | 2018-12-04 | 2020-05-19 | 珠海格力电器股份有限公司 | Arc fault detection and early warning method |
| CN110048375A (en) * | 2019-03-26 | 2019-07-23 | 华为技术有限公司 | A kind of energy-storage system arc-detection and guard method and relevant apparatus |
| CN110441662B (en) * | 2019-08-14 | 2020-10-16 | 中国矿业大学(北京) | Direct current power supply system and method and device for detecting arc fault of direct current power supply system |
| CN110717144B (en) * | 2019-08-19 | 2020-09-22 | 珠海格力电器股份有限公司 | Fault arc detection method, device, terminal and storage medium |
| CN110441663B (en) * | 2019-08-22 | 2021-05-07 | 哈尔滨工业大学 | Method for judging direct current series arc fault based on frequency domain stage ratio value |
| CN113076691A (en) * | 2019-09-23 | 2021-07-06 | 华为技术有限公司 | Direct current arc detection method, device, equipment, system and storage medium |
| CN110618366A (en) * | 2019-11-05 | 2019-12-27 | 阳光电源股份有限公司 | Direct current arc detection method and device |
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