CN112039438B - Method and system for accurately positioning fault trend in photovoltaic array string - Google Patents
Method and system for accurately positioning fault trend in photovoltaic array string Download PDFInfo
- Publication number
- CN112039438B CN112039438B CN202011045152.5A CN202011045152A CN112039438B CN 112039438 B CN112039438 B CN 112039438B CN 202011045152 A CN202011045152 A CN 202011045152A CN 112039438 B CN112039438 B CN 112039438B
- Authority
- CN
- China
- Prior art keywords
- fault
- photovoltaic
- positioning
- module
- current
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
- 238000000034 method Methods 0.000 title claims abstract description 33
- 238000001514 detection method Methods 0.000 claims abstract description 69
- 239000011159 matrix material Substances 0.000 claims abstract description 42
- 238000006243 chemical reaction Methods 0.000 claims abstract description 21
- 230000008859 change Effects 0.000 claims description 31
- 230000009191 jumping Effects 0.000 claims description 18
- 238000007781 pre-processing Methods 0.000 claims description 12
- 238000012986 modification Methods 0.000 claims description 5
- 230000004048 modification Effects 0.000 claims description 5
- 238000003491 array Methods 0.000 claims description 3
- 230000001360 synchronised effect Effects 0.000 claims description 3
- 230000004075 alteration Effects 0.000 claims description 2
- 238000010248 power generation Methods 0.000 abstract description 8
- 238000012544 monitoring process Methods 0.000 abstract 1
- 238000002474 experimental method Methods 0.000 description 5
- 238000004088 simulation Methods 0.000 description 5
- 238000013459 approach Methods 0.000 description 2
- 238000000429 assembly Methods 0.000 description 2
- 230000000712 assembly Effects 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 230000004044 response Effects 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000003745 diagnosis Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 238000011156 evaluation Methods 0.000 description 1
- 238000013100 final test Methods 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 238000011897 real-time detection Methods 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 238000012795 verification Methods 0.000 description 1
Images
Classifications
-
- 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
- H02S50/10—Testing of PV devices, e.g. of PV modules or single PV cells
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E10/00—Energy generation through renewable energy sources
- Y02E10/50—Photovoltaic [PV] energy
Landscapes
- Photovoltaic Devices (AREA)
Abstract
The invention discloses a method and a system for accurately positioning fault trends in a photovoltaic square matrix string, wherein the method for accurately positioning the fault trends comprises the following steps: real-time monitoring of each photovoltaic string branch current I in photovoltaic matrixiThrough IiCalculating the average value of each branch current
Introducing a residual riAnd a predetermined threshold value epsilonTh(ii) a By residual error riAnd a predetermined threshold value epsilonThComparing the sizes of the photovoltaic power generation system and the photovoltaic power generation system to judge whether a photovoltaic string internal fault occurs in a photovoltaic square matrix of the photovoltaic power generation system; if the photovoltaic array fault occurs, whether the photovoltaic array fault automatic detection and positioning model exists in the detection algorithm or not is detected, if the photovoltaic array fault automatic detection and positioning model exists, the photovoltaic array fault automatic detection and positioning model enters the fault automatic detection and positioning algorithm conversion module, when the coefficient residual error Exsit is 1, fault positioning is carried out by using a fault positioning function, and fault positioning information is output. The fault type accurate positioning method for the fault trend has strong pertinence, less calling physical quantity, and can detect the faults in the strings in real time aiming at the faults between the photovoltaic strings in the photovoltaic square matrix and the current detection value of each string, thereby effectively preventing the fault scale from being enlarged.
Description
Technical Field
The invention relates to the field of fault positioning, in particular to a method and a system for accurately positioning a fault trend in a photovoltaic square matrix string.
Background
With the large-scale access of new energy to the power grid, the photovoltaic power generation system in the large-scale power generation of new energy replaces the traditional energy power generation gradually, the stability of the power generation system becomes more important, and the rapid response after the fault occurs prevents the fault from becoming a cascading fault and becomes a key point of concern for protecting the power grid, so the active fault diagnosis and the rapid positioning become key points of research in the academic world gradually.
At present, the fault detection and positioning technology for a photovoltaic square matrix of a photovoltaic power generation system cannot meet the automatic real-time detection of faults, and the fault positioning method is low in response speed and cannot be carried out simultaneously with the fault type detection.
Disclosure of Invention
The invention aims to provide a method and a system for accurately positioning fault trends in a photovoltaic square matrix string, and the method for accurately positioning the fault trends has the advantages of strong pertinence on fault types, less calling physical quantity and strong real-time property: for faults among photovoltaic strings in the photovoltaic square matrix, the faults in the strings can be detected in real time only by depending on current detection values of each string, and the scale of the faults is effectively prevented from being enlarged; and (3) introducing concepts of residual errors and preset thresholds, and optimizing the efficiency of a fault detection algorithm: the photovoltaic array is tightly grasped to generate power, each branch circuit current is theoretically the same, so that the difference between the average value of each branch circuit current of the photovoltaic array and the actual current of each branch circuit is not large, the difference value is defined as residual error, and if the difference value is larger than a preset threshold value, the occurrence of faults in the string is indicated; the method is taken as the theme of the fault detection algorithm, only one physical quantity needs to be compared, and the fault detection efficiency of the algorithm is greatly improved;
the method is suitable for photovoltaic square matrix without the limitation of the square matrix scale, and the algorithm applicability is high: the positioning algorithm comprises an algorithm conversion module, and conversion of a positioning function can be performed according to the number change of photovoltaic strings or photovoltaic modules of a photovoltaic square matrix from a basic square matrix, so that the algorithm applicability is improved.
The purpose of the invention can be realized by the following technical scheme:
a method for accurately positioning fault trends in a photovoltaic square matrix string comprises the following steps:
s1: each photovoltaic string current I in synchronous photovoltaic square matrixi；
S2: calculating the average value of each branch current
S3: residual error calculating branch current IiWith the average value of the total current
Between which a residual error r appearsiAn indication signal for the occurrence of a fault;
s4: residual judgment
Residual riGreater than a threshold value epsilonThAnd when the system has a fault in the photovoltaic string, the system gives a warning and jumps to S5, the residual error riLess than a predetermined threshold epsilon for a faultThThen a jump back to S1;
s5: judging whether a photovoltaic array fault automatic detection and positioning model exists in the algorithm system, namely, checking whether the coefficient residual error Exsit is 1, if so, jumping to S7, otherwise, setting the parameter Exsit to 1, and jumping to S6;
s6: performing fault location by using a fault location function, and jumping to S11 after completion;
whether a coefficient residual error Exsist detection algorithm is operated or not, namely whether a photovoltaic array fault automatic detection and positioning model exists or not is detected, if yes, the photovoltaic array fault automatic detection and positioning algorithm conversion module is started, if not, the Exsist is set to be 1, and the photovoltaic array fault automatic detection and positioning model enters a fault positioning module;
s7: judging whether the number of the photovoltaic modules of each photovoltaic string of the newly input photovoltaic square matrix is the same as that of the existing photovoltaic square matrix in the system, if not, jumping to S8, and if so, jumping to S10;
s8: judging whether the number of the photovoltaic strings of the newly input photovoltaic square matrix is the same as that of the existing photovoltaic square matrix in the system, if so, jumping to S9, and if not, reporting an error;
s9: changing slope of original fault location function, changing branch current expression in fault location function, passing through Li＝f(G,IiM) updating the fault positioning function;
s10: changing slope of original fault location function, changing branch current expression in fault location function, passing through Li＝f(G,IiN) updating a fault positioning function;
s11: and outputting fault positioning information.
Further, I in S2aAs the total current, IiI is the branch current, n is the total number of branches.
Further, a threshold value epsilon is preset by a fault in S3ThDetermining a residual riWhen the branch residual riLess than a predetermined threshold epsilon for a faultThWhen the current of each branch is close to similarity, the residual error approaches to zero, and no fault photovoltaic string exists in the system; branch residual error riGreater than a predetermined fault threshold epsilonThWhen the current of the branch circuit is unbalanced, the i branch circuit in the system breaks down;
further, when no automatic photovoltaic array fault detection and positioning model exists in the algorithm system in the step S5, the algorithm system directly enters a fault positioning module; when the method is used for initializing the automatic detection of the faults of the photovoltaic array and generating a positioning model, the formula L is usedi＝f(G,Ii) Alternative formula Li＝f(G,IiM, n, T); the method comprises the steps of performing intra-string fault traversal of each photovoltaic string on the current common 4 x 4, 6 x 3 and 15 x 4 photovoltaic arrays, and performing L under each fault conditioni-G-IiAfter recording, approximately accurate L is obtained by analyzing a large amount of datai＝f(G,Ii) A functional relation;
Li＝f(G,Ii,m,n,T)
Li＝f(G,Ii)。
further, said LiFor fault location, G is irradiance and T is temperature.
Further, when the number of the photovoltaic modules is changed in S9, the magnitude range of the current is not changed, and the slope S of the relationship curve between the fault position and the branch current is not changednewChange to a formula
When the slope of the relationship curve is changed, the branch current Ii(new)Change into formula
Li＝f(G,Ii,m)
Further, said snewIn order to change the slope of the curve after the change,soldto change the slope of the curve, mnewTo change the number of photovoltaic modules, moldTo change the number of photovoltaic modules, m is the number of photovoltaic modules.
Further, when the number of the photovoltaic strings in S10 changes, the magnitude of the current changes linearly with the change, so that in this case, the slope S of the relationship curve between the fault position and the branch currentnewChange to the formula snew＝nratio×nold×nnew(ii) a When the slope of the relationship curve is changed, the branch current Ii(new)Change into formula
Further, said nratioRepresenting the ratio of the number of photovoltaic strings before and after modification, noldAnd nnewIndicating the number of photovoltaic strings before and after the change.
The fault trend accurate positioning system in the photovoltaic array string comprises a data reading module, a data preprocessing module, a residual error judging module, a fault warning module, an automatic fault detection and positioning module and an automatic fault detection and positioning algorithm conversion module, wherein the data reading module reads current I of each photovoltaic string in the photovoltaic arrayi；
The data preprocessing module calculates the average value of the current of each branch circuit by using the current value of each photovoltaic string transmitted by the data reading module
And calculating the branch current IiWith the average value of the total current
Residual error r betweeni；
The residual error judgment module compares the residual errors by using the output of the data preprocessing module, and the residual error riGreater than a threshold value epsilonThWhen the system has photovoltaic string faults, the fault warning module is called, and residual errors riLess than a predetermined threshold epsilon for a faultThThe data reading module is called again, and the data preprocessing module and the residual error judgment module are executed in sequence;
the fault warning module pushes system alarm information to a user side, judges whether an automatic photovoltaic array fault detection and positioning model exists in an algorithm system or not, and calls the automatic fault detection and positioning module or the automatic fault detection and positioning algorithm conversion module according to a judgment result;
the automatic fault detection and positioning module is used for positioning faults by using a fault positioning function and pushing positioning information to the client after the fault positioning function is completed;
the automatic fault detection and positioning algorithm conversion module operates in a system and has a photovoltaic array automatic fault detection and positioning model, and the automatic fault detection and positioning algorithm conversion module carries out parameter change on the existing positioning model and pushes positioning information to a client after the parameter change is completed.
The invention has the beneficial effects that:
1. the fault type accurate positioning method for the fault trend has strong pertinence, less calling physical quantity and stronger instantaneity: for faults among photovoltaic strings in the photovoltaic square matrix, the faults in the strings can be detected in real time only by depending on current detection values of each string, and the scale of the faults is effectively prevented from being enlarged;
2. the fault trend accurate positioning method of the invention introduces the concepts of 'residual error' and a preset threshold value, optimizes the efficiency of a fault detection algorithm: the photovoltaic array is tightly grasped to generate power, each branch circuit current is theoretically the same, so that the difference between the average value of each branch circuit current of the photovoltaic array and the actual current of each branch circuit is not large, the difference value is defined as residual error, and if the difference value is larger than a preset threshold value, the occurrence of faults in the string is indicated; the method is taken as the theme of the fault detection algorithm, only one physical quantity needs to be compared, and the fault detection efficiency of the algorithm is greatly improved;
3. the fault trend accurate positioning method is suitable for the photovoltaic square matrix and is not limited by the square matrix scale, and the algorithm applicability is higher: the positioning algorithm comprises an algorithm conversion module, and conversion of a positioning function can be performed according to the number change of photovoltaic strings or photovoltaic modules of a photovoltaic square matrix from a basic square matrix, so that the algorithm applicability is improved.
Drawings
The invention will be further described with reference to the accompanying drawings.
FIG. 1 is a flow chart of a positioning method of the present invention;
fig. 2 is a schematic diagram of a positioning system module of the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
The fault trend accurate positioning system in the photovoltaic array string comprises a data reading module, a data preprocessing module, a residual error judging module, a fault warning module, an automatic fault detection and positioning module and an automatic fault detection and positioning algorithm conversion module, wherein the data reading module reads current I of each photovoltaic string in the photovoltaic arrayi；
The data preprocessing module calculates the average value of the current of each branch circuit by using the current value of each photovoltaic string transmitted by the data reading module
And calculating the branch current IiWith the average value of the total current
Residual error r betweeni；
The residual error judgment module compares the residual errors by using the output of the data preprocessing module, and the residual error riGreater than a threshold value epsilonThWhen the system has photovoltaic string faults, the fault warning module is called, and residual errors riLess than a predetermined threshold epsilon for a faultThThe data reading module is called again to execute the data preprocessing in sequenceA processing module and a residual error judging module;
the fault warning module pushes system alarm information to a user side, judges whether an automatic photovoltaic array fault detection and positioning model exists in an algorithm system or not, and calls the automatic fault detection and positioning module or the automatic fault detection and positioning algorithm conversion module according to a judgment result;
the automatic fault detection and positioning module is used for positioning faults by using a fault positioning function and pushing positioning information to the client after the fault positioning function is completed;
the automatic fault detection and positioning algorithm conversion module operates in a system and has a photovoltaic array automatic fault detection and positioning model, and the automatic fault detection and positioning algorithm conversion module carries out parameter change on the existing positioning model and pushes positioning information to a client after the parameter change is completed.
A method for accurately positioning fault trends in a photovoltaic square matrix string comprises the following steps:
s1: each photovoltaic string current I in synchronous photovoltaic square matrixi；
S2: calculating the average value of each branch current
In the formula: i isaAs a result of the total current flow,
is the average value of the total current, IiIs the branch current, i is the branch, n is the total number of branches, riIs the residual error.
S3: residual error calculating branch current IiWith the average value of the total current
Between which a residual error r appearsiAn indication signal for the occurrence of a fault; by presetting a threshold value epsilon for a faultThDetermining a residual riWhen the branch residual riLess than a predetermined threshold epsilon for a faultThWhen the current of each branch is close to similarity, the residual error approaches to zero, and no fault photovoltaic string exists in the system; branch residual error riGreater than a predetermined fault threshold epsilonThWhen the current of the branch is unbalanced, the i branch in the system breaks down.
S4: residual judgment
Residual riGreater than a threshold value epsilonThAnd when the system has a fault in the photovoltaic string, the system gives a warning and jumps to S5, the residual error riLess than a predetermined threshold epsilon for a faultThA jump is made back to S1.
S5: judging whether a photovoltaic array fault automatic detection and positioning model exists in the algorithm system, namely, checking whether the coefficient residual error Exsit is 1, if so, jumping to S7, otherwise, setting the parameter Exsit to 1, and jumping to S6;
when the automatic detection and positioning model of the photovoltaic array fault does not exist in the algorithm system, the photovoltaic array fault directly enters a fault positioning module; when the method is used for initializing the automatic detection of the faults of the photovoltaic array and generating a positioning model, the formula L is used as a default since the size mxn of the photovoltaic array is certain, and the change of the environmental temperature T is not large in a certain rangei＝f(G,Ii) Alternative formula Li＝f(G,IiM, n, T); the method comprises the steps of performing intra-string fault traversal of each photovoltaic string on the current common 4 x 4, 6 x 3 and 15 x 4 photovoltaic arrays, and performing L under each fault conditioni-G-IiAfter recording, approximately accurate L is obtained by analyzing a large amount of datai＝f(G,Ii) And (4) functional relation.
Li＝f(G,Ii,m,n,T)
Li＝f(G,Ii)
In the formula: l isiFor fault location, G is irradiance and T is temperature.
S6: performing fault location by using a fault location function, and jumping to S11 after completion;
and (3) detecting whether the algorithm is operated or not through the coefficient residual error Exsit, namely whether a photovoltaic array fault automatic detection and positioning model exists or not, if so, entering a fault automatic detection and positioning algorithm conversion module, and if not, setting Exsit to be 1 and entering a fault positioning module.
S7: judging whether the number of the photovoltaic modules of each photovoltaic string of the newly input photovoltaic square matrix is the same as that of the existing photovoltaic square matrix in the system, if not, jumping to S8, and if so, jumping to S10;
the cases of transferring to the algorithm conversion module are divided into two cases, 1) the number of the photovoltaic strings is not changed, and the number of the photovoltaic modules is different; 2) the number of the photovoltaic strings is different, and the number of the photovoltaic modules is unchanged.
S8: and judging whether the number of the photovoltaic strings of the newly input photovoltaic square matrix is the same as that of the existing photovoltaic square matrix in the system, if so, jumping to S9, and otherwise, reporting an error.
S9: using formulas
Changing the slope of the original fault location function by using the formula
Changing branch current expression in fault location function, and substituting the above into formula Li＝f(G,IiM) updating the fault positioning function;
when the number of the photovoltaic modules is changed, the magnitude range of the current is not changed, so that the slope s of the relation curve between the fault position and the branch current in the casenewChange to a formula
Wherein m isoldAnd mnewBefore indicating a changeAnd the number of photovoltaic modules after modification; when the slope of the relationship curve is changed, the branch current Ii(new)Change into formula
Li＝f(G,Ii,m)
In the formula: snewFor the slope of the curve after alteration, soldTo change the slope of the curve, mnewTo change the number of photovoltaic modules, moldTo change the number of photovoltaic modules, m is the number of photovoltaic modules.
S10: using the formula snew＝nratio×nold×nnewChanging the slope of the original fault location function by using the formula
Changing branch current expression in fault location function, and substituting the above into formula Li＝f(G,IiN) updating a fault positioning function;
when the number of the photovoltaic strings is changed, the magnitude of the current is linearly changed along with the photovoltaic strings, so that the slope s of the relation curve between the fault position and the branch current in the casenewChange to the formula snew＝nratio×nold×nnewWherein n isratioRepresenting the ratio of the number of photovoltaic strings before and after modification, noldAnd nnewRepresenting the number of photovoltaic strings before and after the change; when the slope of the relationship curve is changed, the branch current Ii(new)Change into formula
S11: and outputting fault positioning information.
Example 1
When the photovoltaic square matrix scale is 4 multiplied by 4, different assemblies in any branch photovoltaic square matrix string have faults, and the automatic fault detection parameter residual error and the fault position positioning algorithm simulation result are shown in table 1; the results of the actual experiments are shown in table 2.
TABLE 1 Algorithm simulation results
TABLE 2 results of the actual experiments
Example 2
When the photovoltaic square matrix scale is 6 multiplied by 3, different assemblies in any branch photovoltaic square matrix string have faults, and the automatic fault detection parameters 'residual errors' and the final fault position positioning detection results are shown in table 3; the results of the actual experiments are shown in table 4.
TABLE 3 simulation results of the Algorithm
TABLE 4 results of the actual experiments
Example 3
The scale of the existing photovoltaic square matrix in the algorithm is 4 multiplied by 3, when the scale is converted into 6 multiplied by 3, different components in any branch photovoltaic square matrix string have faults, and the final detection results of the automatic fault detection parameters 'residual error' and the fault position positioning are shown in table 5
TABLE 5 Final test results
In example 1, the photovoltaic square contains four photovoltaic strings, each string having four photovoltaic modules connected in series, the line faults within the photovoltaic strings are generated at different irradiance levels, and the faults are generated at different locations along string No. 1. For each simulation fault scene, calculating the residual error of each photovoltaic string, and judging the fault position; in an actual experiment, a current sensor is placed at the tail end of each photovoltaic string to analyze the influence of a line fault on the magnitude of the string current; for each irradiance level, a fault is generated along string 1 and the corresponding string current is measured; the results of table 2 confirm that the proposed method is able to accurately detect and locate intra-string line faults; performance in estimating fault location is particularly noticeable; the proposed method enables to estimate the position at different irradiance levels with high accuracy.
In example 2, under different irradiation conditions, intra-string faults were generated along string 1, and the corresponding string currents were measured in the simulation; the irradiance level need only move the characteristic up and down without changing the slope of the characteristic. Table 3 summarizes the results of the fault detection and location, confirming that the method can accurately detect the fault and perform location according to the fault module number; experimental verification was performed on a 6 x 3 photovoltaic array; for evaluation, faults within the string are introduced in sequence at each position from position 1 to position 6 in string 1; the fault detection and location estimation results are shown in table 4; the results show that the method can successfully detect and locate faults regardless of the array structure; further, as can be seen from table 4, as the experimental fault location increases, the accuracy of estimating the fault location increases.
In example 3, in this case, we can use the formula
The slope of the line characterizing the current is obtained relative to the fault location. By general formula
Substituted Li＝f(G,IiM), a fault locating expression for the new array size may be obtained. The method was validated on a 6 x 3 array with the results shown in table 5; experimental results prove that the method can popularize m modules with reasonable fault positioning accuracy; similar to the results presented in example 2.
In the description herein, references to the description of "one embodiment," "an example," "a specific example" or the like are intended to mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.
The foregoing shows and describes the general principles, essential features, and advantages of the invention. It will be understood by those skilled in the art that the present invention is not limited to the embodiments described above, which are described in the specification and illustrated only to illustrate the principle of the present invention, but that various changes and modifications may be made therein without departing from the spirit and scope of the present invention, which fall within the scope of the invention as claimed.
Claims (4)
1. A method for accurately positioning fault trends in a photovoltaic square matrix string is characterized by comprising the following steps:
s1: each photovoltaic string current I in synchronous photovoltaic square matrixi；
S2: calculating the average value of each branch current
In the formula IaAs the total current, IiIs the branch current, i is the branch, n is the total number of branches;
s3: residual error calculating branch current IiWith the average value of the total current
Between which a residual error r appearsiAn indication signal for the occurrence of a fault;
s4: residual judgment
Residual riGreater than a threshold value epsilonThAnd when the system has a fault in the photovoltaic string, the system gives a warning and jumps to S5, the residual error riLess than a predetermined threshold epsilon for a faultThThen a jump back to S1;
s5: judging whether a photovoltaic array fault automatic detection and positioning model exists in the algorithm system, namely, checking whether the coefficient residual error Exsit is 1, if so, jumping to S7, otherwise, setting the parameter Exsit to 1, and jumping to S6;
when the automatic detection and positioning model of the photovoltaic array fault does not exist in the algorithm system, the photovoltaic array fault directly enters a fault positioning module; when the method is used for initializing the automatic detection of the faults of the photovoltaic array and generating a positioning model, a positioning function L is usedi＝f(G,Ii) Alternative initial positioning function Li＝f(G,IiM, n, T); by performing intra-string fault traversals of individual photovoltaic strings for 4 x 4, 6 x 3 and 15 x 4 photovoltaic arrays, and for L in each fault casei-G-IiAfter recording, approximately accurate L is obtained by analyzing the datai＝f(G,Ii) A functional relation;
Li＝f(G,Ii)
in the formula LiFor this reasonBarrier positions, G is irradiance, T is temperature, and m is the number of photovoltaic modules;
s6: performing fault location by using a fault location function, and jumping to S11 after completion;
whether a coefficient residual error Exsist detection algorithm is operated or not, namely whether a photovoltaic array fault automatic detection and positioning model exists or not is detected, if yes, the photovoltaic array fault automatic detection and positioning algorithm conversion module is started, if not, the Exsist is set to be 1, and the photovoltaic array fault automatic detection and positioning model enters a fault positioning module;
s7: judging whether the number of the photovoltaic modules of each photovoltaic string of the newly input photovoltaic square matrix is the same as that of the existing photovoltaic square matrix in the system, if not, jumping to S8, and if so, jumping to S10;
s8: judging whether the number of the photovoltaic strings of the newly input photovoltaic square matrix is the same as that of the existing photovoltaic square matrix in the system, if so, jumping to S9, and if not, reporting an error;
s9: when the number of the photovoltaic modules is changed, the slope of the original fault positioning function is changed, the branch current expression in the fault positioning function is changed, and the current expression passes through Li＝f(G,IiM) updating the fault positioning function;
s10: when the total number of the branches changes, the slope of the original fault positioning function is changed, the branch current expression in the fault positioning function is changed, and the current expression passes through Li＝f(G,IiN) updating a fault positioning function;
s11: and outputting fault positioning information.
2. The method according to claim 1, wherein when the number of photovoltaic modules in S9 changes, the magnitude range of the current does not change, and the slope S of the relationship curve between the fault position and the branch current isnewChange to a formula
When the slope of the relationship curve is changed, the branch current Ii(new)Change into formula
In the formula snewFor the slope of the curve after alteration, soldTo change the slope of the curve, mnewTo change the number of photovoltaic modules, moldThe number of photovoltaic modules before change.
3. The method according to claim 1, wherein the magnitude of the current changes linearly with the number of the photovoltaic strings in S10, so that the slope S of the relationship curve between the fault location and the branch current in this casenewChange to the formula snew＝nratio×nold×nnew(ii) a When the slope of the relationship curve is changed, the branch current Ii(new)Change into formula
In the formula nratioRepresenting the ratio of the number of photovoltaic strings before and after modification, noldAnd nnewIndicating the number of photovoltaic strings before and after the change.
4. The positioning system of the fault trend accurate positioning method according to any one of claims 1 to 3, wherein the positioning system comprises a data reading module, a data preprocessing module, a residual error judgment module, a fault warning module, an automatic fault detection and positioning module and an automatic fault detection and positioning algorithm conversion module, and is characterized in that: the data reading module reads the current I of each photovoltaic string in the photovoltaic square matrixi；
The data preprocessing module calculates the average value of the current of each branch circuit by using the current value of each photovoltaic string transmitted by the data reading module
And calculating the branch current IiWith the average value of the total current
Residual error r betweeni；
The residual error judgment module compares the residual errors by using the output of the data preprocessing module, and the residual error riGreater than a threshold value epsilonThWhen the system has photovoltaic string faults, the fault warning module is called, and residual errors riLess than a predetermined threshold epsilon for a faultThThe data reading module is called again, and the data preprocessing module and the residual error judgment module are executed in sequence;
the fault warning module pushes system alarm information to a user side, judges whether an automatic photovoltaic array fault detection and positioning model exists in an algorithm system or not, and calls the automatic fault detection and positioning module or the automatic fault detection and positioning algorithm conversion module according to a judgment result;
the automatic fault detection and positioning module is used for positioning faults by using a fault positioning function and pushing positioning information to the client after the fault positioning function is completed;
the automatic fault detection and positioning algorithm conversion module operates in a system and has a photovoltaic array automatic fault detection and positioning model, and the automatic fault detection and positioning algorithm conversion module carries out parameter change on an existing positioning function and pushes positioning information to a client after the parameter change is completed.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011045152.5A CN112039438B (en) | 2020-09-28 | 2020-09-28 | Method and system for accurately positioning fault trend in photovoltaic array string |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011045152.5A CN112039438B (en) | 2020-09-28 | 2020-09-28 | Method and system for accurately positioning fault trend in photovoltaic array string |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN112039438A CN112039438A (en) | 2020-12-04 |
| CN112039438B true CN112039438B (en) | 2021-08-10 |
Family
ID=73574808
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202011045152.5A Active CN112039438B (en) | 2020-09-28 | 2020-09-28 | Method and system for accurately positioning fault trend in photovoltaic array string |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN112039438B (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113541600B (en) * | 2021-05-25 | 2022-09-06 | 特变电工新疆新能源股份有限公司 | Method, system, equipment and storage medium for judging branch fault of photovoltaic power station |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20120299387A1 (en) * | 2011-05-27 | 2012-11-29 | Indiana Research & Technology Corporation | Diagnostics of integrated solar power |
| CN104049171A (en) * | 2014-06-12 | 2014-09-17 | 中南大学 | Open-circuit fault diagnosis method and system for staggered flyback type micro inverter |
| CN106603006A (en) * | 2016-12-14 | 2017-04-26 | 河海大学常州校区 | Look-up table interpolation-based photovoltaic array fault diagnosing and positioning method |
-
2020
- 2020-09-28 CN CN202011045152.5A patent/CN112039438B/en active Active
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20120299387A1 (en) * | 2011-05-27 | 2012-11-29 | Indiana Research & Technology Corporation | Diagnostics of integrated solar power |
| CN104049171A (en) * | 2014-06-12 | 2014-09-17 | 中南大学 | Open-circuit fault diagnosis method and system for staggered flyback type micro inverter |
| CN106603006A (en) * | 2016-12-14 | 2017-04-26 | 河海大学常州校区 | Look-up table interpolation-based photovoltaic array fault diagnosing and positioning method |
Non-Patent Citations (1)
| Title |
|---|
| 基于改进BP神经网络的光伏阵列多传感器故障检测定位方法研究;李云桥;《西安理工大学硕士学位论文》;20181218;第2章、第4章 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN112039438A (en) | 2020-12-04 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN109766952B (en) | Photovoltaic array fault detection method based on partial least square method and extreme learning machine | |
| CN108053128B (en) | Electric network transient stability rapid evaluation method based on ELM and TF | |
| CN109765490B (en) | Power battery fault detection method and system based on high-dimensional data diagnosis | |
| CN110289613B (en) | Sensitivity matrix-based power distribution network topology identification and line parameter identification method | |
| CN111402078B (en) | Photovoltaic string diagnosis method, device and controller | |
| CN110071692B (en) | Photovoltaic module fault determination method and device and controller | |
| CN113242209B (en) | Generalized accumulation and detection method for false data injection attack of smart grid | |
| CN110008628A (en) | A kind of photovoltaic array fault parameter discrimination method | |
| CN112039438B (en) | Method and system for accurately positioning fault trend in photovoltaic array string | |
| CN112288326A (en) | Fault scene set reduction method suitable for toughness evaluation of power transmission system | |
| CN112379213A (en) | Fault detection method and system | |
| CN112565187A (en) | Power grid attack detection method, system, equipment and medium based on logistic regression | |
| CN115508719A (en) | Method and system for diagnosing abnormal single battery cell in series battery pack, storage medium and terminal | |
| CN114201483A (en) | Photovoltaic array fault diagnosis method based on statistical modeling | |
| CN117293799A (en) | Method and system for evaluating transient power angle stability of power system | |
| CN106777719B (en) | Fault detection method of dual-mode redundant fault detection device | |
| CN112684343A (en) | Battery fault judgment method, detection device and detection system | |
| CN117118355A (en) | Photovoltaic panel fault detection method and device, storage medium and electronic equipment | |
| CN109581194B (en) | Dynamic generation method for electronic system fault test strategy | |
| CN116148599A (en) | Kurtosis and skewness coefficient-based high-resistance ground fault diagnosis protection method and device | |
| CN116820821A (en) | Disk failure detection method, apparatus, electronic device and computer readable storage medium | |
| CN116827263A (en) | Photovoltaic cell fault detection method, device, computer equipment and medium | |
| CN115982914A (en) | Grounding grid corrosion assessment method and system based on elastic grid theory | |
| CN115343579A (en) | Power grid fault analysis method and device and electronic equipment | |
| CN114928045A (en) | Power grid safety and stability control strategy verification method and system |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |