CN113253047A - Single-phase grounding line selection method and device, electronic equipment and storage medium - Google Patents
Single-phase grounding line selection method and device, electronic equipment and storage medium Download PDFInfo
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- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
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- G—PHYSICS
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- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
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Abstract
The invention discloses a single-phase grounding line selection method, which constructs a special sampling signal matrix A by utilizing a zero-sequence current sampling signal sequence of each branch in a section after a grounding fault, and obtains a reconstructed sampling signal sequence after filtering and noise reduction by performing singular value decomposition and reconstruction on the matrix A
And selecting a reconstructed sampling signal sequence of the reference branch, performing inner product operation on the reconstructed sampling signal sequence of the reference branch and the reconstructed sampling signal sequences of the rest branches, judging the positive and negative conditions of the operation result, and selecting a fault branch. The method has good noise elimination and weak signal extraction effects and higher frequency resolution, is different from the wavelet transform that parameters such as wavelet basis function, decomposition scale and the like need to be subjectively determined, does not need to determine similar parameters in advance, and has the characteristics of zero phase shift and the like, which are accurate in improving line selectionThe rate has a beneficial effect.
Description
Technical Field
The invention relates to the field of relay protection of power systems, in particular to a single-phase earth fault line selection method and device of a low-current grounding system, electronic equipment and a storage medium.
Background
In a 3 kV-66 kV low current grounding system (also called a neutral point non-effective grounding system), single-phase grounding is a common fault type. When the small current grounding system is in single-phase grounding, the voltage of a fault phase-to-ground voltage is reduced, the voltage of a non-fault phase-to-ground voltage is increased, the line voltage is still symmetrical, and the small current grounding system can generally allow the small current grounding system to operate for 1-2 h in order to ensure the power supply reliability. However, the arc overvoltage of the single-phase grounded non-fault phase easily causes the problems of breakdown of a weak insulating part, saturation of an iron core of a voltage transformer, system overvoltage, cable burnout of arc light of the fault phase, personal electric shock casualty accidents and the like, so that the fault needs to be timely judged and isolated after the single-phase grounded, and the safe and stable operation and the personal safety of a system are guaranteed.
When single-phase earth faults occur, a relatively obvious transient process exists, the amplitude of a characteristic signal is relatively large in a short time, particularly, the transient earth capacitance current is often several times to dozens of times larger than that of the transient earth capacitance current in a steady state, the process contains abundant fault characteristics, and favorable conditions are provided for extracting the fault characteristics to select lines.
The wavelet theory provides a very good tool for analyzing transient signals, and the research of analyzing and selecting lines for the transient signals by adopting wavelets (wavelet packets) is applied to the line selection of the ground fault, so that a good effect is achieved. But still has the disadvantages that: the wavelet transformation is non-adaptive transformation, and has higher requirements on the artificial accurate selection of the wavelet basis function and the decomposition scale, otherwise, the analysis effect is possibly not ideal, and the subjectivity of the selection of the wavelet basis function and the decomposition scale reduces the practical application effect of the wavelet basis function and the decomposition scale.
Disclosure of Invention
The purpose of the invention is as follows: aiming at the problems, the single-phase grounding line selection method is provided, and the method adopts Singular Value Decomposition (SVD) to perform signal processing on discrete sampling data so as to extract the zero phase offset of the signal characteristic quantity in the disturbance and noise environment and simultaneously has the characteristic of no need of subjectively determining analysis parameters. The application also provides a corresponding device, electronic equipment and storage medium.
In order to achieve the above purpose, the solution of the invention is:
according to a first aspect of the present application, there is provided a single-phase grounding line selection method, including:
acquiring a zero sequence current sampling signal sequence X of each branch on a bus in a set time after a ground fault occursiWherein i is the serial number of each branch put into operation on the bus, L is the number of branches put into operation on the bus, and i is 1,2, … and L;
based on the sampling signal sequence XiConstructing a sampling signal matrix Ai；
For the sampling signal matrix AiSingular value decomposition is carried out to obtain singular matrix SiThe singular matrix SiAfter the medium and non-effective singular values are set to zero, a reconstruction matrix A 'is obtained by utilizing a singular value inverse decomposition process'i；
Reconstructing the matrix A'iThe elements in each row are spliced end to obtain a reconstructed sampling signal sequence after filtering and noise reduction of the corresponding branch
Setting a reference branch, and sequentially performing inner product operation on a reconstructed sampling signal sequence of the reference branch and reconstructed sampling signal sequences of the other branches;
and selecting a fault branch based on the inner product operation result.
Preferably, the method further comprises:
acquiring zero-sequence voltage of a bus of a transformer substation and zero-sequence current signals of all branches on the bus in real time;
calculating a zero-sequence voltage amplitude value based on the zero-sequence voltage;
and determining the initial moment of the fault based on the fact that the zero sequence voltage amplitude exceeds a fixed value threshold.
Preferably, the set time is a cycle time.
Preferably, the signal sequence X is based on the sampling signaliConstructing a sampling signal matrix AiThe method specifically comprises the following steps: truncating the sequence of sampled signals X successivelyiThe equal length data of (a) are sequentially taken as the rows of the sampling signal matrix.
Preferably, the method for determining the non-significant singular value includes:
calculating the root mean square of all singular values;
and comparing each singular value with the root mean square, judging the singular value to be an effective singular value if the singular value is larger than the root mean square, and judging the singular value to be a non-effective singular value if the singular value is not larger than the root mean square.
Preferably, the pair of sampling signal matrixes aiSingular value decomposition is carried out to obtain singular matrix SiThe singular matrix SiAfter the medium and non-effective singular values are set to zero, a reconstruction matrix A 'is obtained by utilizing a singular value inverse decomposition process'iThe method comprises the following steps:
for the sampling signal matrix AiCarrying out singular value decomposition to obtain a matrix AiR singular values and a singular matrix Si＝diag(σi1,σi2,...,σir0, 0.. 0), left singular matrix UiAnd right singular matrix ViThe relationship between them is: a. thei＝UiSiVi T(ii) a Wherein σi1Is a matrix AiFirst singular value ofi2Is a matrix AiSecond singular value of σirIs a matrix AiThe r-th singular value of (a); vi TRepresenting the right singular matrix ViThe transposed matrix of (2);
judging the validity of the singular value, if the number of the effective singular value is p (p is less than or equal to r), reserving a singular matrix SiSetting the rest non-effective singular values in the singular matrix to zero to form new singular matrix
By using
Obtaining a reconstruction matrix A 'through a right-left singular value inverse decomposition process'i。
Preferably, the selecting a faulty branch based on the inner product operation result specifically includes:
if the inner product operation result of the reference branch and a certain branch is greater than zero, indicating that the certain branch and the reference branch have the same polarity; if the inner product operation result of the reference branch and a certain branch is less than zero, indicating that the certain branch and the reference branch are of opposite polarities;
if the reference branch and one branch are reverse polarity, the branch is a fault grounding branch; if the reference branch and all other branches are reversed polarity, the reference branch is a fault grounding branch; and if the reference branch and all other branches are in the same polarity, the bus grounding fault is detected.
According to a second aspect of the present application, there is provided a single-phase ground line selection device, comprising:
a sampling signal sequence acquisition module for acquiring a zero sequence current sampling signal sequence X of each branch on the bus in a set time after the occurrence of the ground faultiWherein i is the serial number of each branch put into operation on the bus, L is the number of branches put into operation on the bus, and i is 1,2, … and L;
a sampling signal matrix construction module for constructing a matrix based on the sampling signal sequence XiConstructing a sampling signal matrix Ai；
A reconstruction matrix module for reconstructing the sampling signal matrix AiSingular value decomposition is carried out to obtain singular matrix SiThe singular matrix SiAfter the medium and non-effective singular values are set to zero, a reconstruction matrix A 'is obtained by utilizing a singular value inverse decomposition process'i；
A reconstruction sampling signal sequence acquisition module for acquiring the reconstruction matrix A'iThe elements in each row are spliced end to obtain a reconstructed sampling signal sequence after filtering and noise reduction of the corresponding branch
The inner product operation module is used for setting a reference branch and sequentially carrying out inner product operation on the reconstructed sampling signal sequence of the reference branch and the reconstructed sampling signal sequences of the other branches;
and the line selection module is used for selecting a fault branch based on the inner product operation result.
According to a third aspect of the present application, there is provided an electronic device comprising:
a processor; and
a memory storing computer instructions which, when executed by the processor, cause the processor to perform the method of the first aspect.
According to a fourth aspect of the present application, there is provided a non-transitory computer storage medium storing a computer program which, when executed by a plurality of processors, causes the processors to perform the method of the first aspect.
The invention has the beneficial effects that:
by constructing a sampling signal matrix and carrying out Singular Value Decomposition (SVD), the method can realize the relatively stable extraction of the characteristic quantity of the sampling signal under disturbance noise, has good frequency resolution and good noise elimination and weak signal extraction effects, simultaneously has no need of subjectively determining analysis parameters such as similar wavelet basis functions in advance, and has beneficial effects on improving the accuracy rate of line selection.
Drawings
Fig. 1 is a flowchart of a single-phase ground line selection method according to an embodiment of the present application.
Fig. 2 is a schematic diagram of a method for obtaining a reconstructed sampling signal sequence after filtering and denoising of corresponding branches by splicing reconstruction matrices.
Fig. 3 is a schematic wiring diagram implemented in the ground line selection apparatus of the present invention.
Fig. 4 is a schematic diagram of a single-phase ground line selection device according to an embodiment of the present application.
Fig. 5 is a block diagram of an electronic device provided in the present application.
Detailed Description
The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are some, but not all, embodiments of the present application. 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 application.
Fig. 1 is a flowchart of a single-phase ground line selection method according to an embodiment of the present application, and as shown in fig. 1, the method includes the following steps:
s100, acquiring zero sequence current sampling signal sequence X of each branch on bus in set time after ground fault occursiWherein, i is the serial number of each branch put into operation on the bus, L is the number of branches put into operation on the bus, and i is 1,2, …, L.
According to some embodiments, the set time is selected to be one cycle duration.
S200, based on the sampling signal sequence XiConstructing a sampling signal matrix Ai。
According to some embodiments, XiConstructing a sampling signal matrix AiThe method comprises the following steps: truncating the sequence of sampled signals X successivelyiThe equal length data of (a) are sequentially taken as the rows of the sampling signal matrix.
S300, for the sampling signal matrix AiSingular value decomposition is carried out to obtain singular matrix SiThe singular matrix SiAfter the medium and non-effective singular values are set to zero, a reconstruction matrix A 'is obtained by utilizing a singular value inverse decomposition process'i。
According to some embodiments, step S300 may be broken down into the following steps:
s301: for the sampling signal matrix AiCarrying out singular value decomposition to obtain a matrix AiR singular values and a singular matrix Si＝diag(σi1,σi2,...,σir0, 0.. 0), left singular matrix UiAnd right singular matrix ViThe relationship between them is: a. thei＝UiSiVi T(ii) a Wherein σi1Is a matrix AiFirst singular value ofi2Is a matrix AiSecond singular value of σirIs a matrix AiThe r-th singular value of (a); vi TRepresenting the right singular matrix ViThe transposed matrix of (2);
s302: judging the validity of the singular value, if the number of the effective singular value is p (p is less than or equal to r), reserving a singular matrix SiSetting the other non-effective singular values in the singular matrix to zero to form a new singular matrix
S303: by using
Obtaining a reconstruction matrix A 'through a right-left singular value inverse decomposition process'i。
According to some embodiments, the method for determining the non-significant singular value includes: calculating the root mean square of all singular values; and comparing each singular value with the root mean square, judging the singular value to be an effective singular value if the singular value is larger than the root mean square, and judging the singular value to be a non-effective singular value if the singular value is not larger than the root mean square.
S400, reconstructing the matrix A'iThe elements in each row are spliced end to obtain a reconstructed sampling signal sequence after filtering and noise reduction of the corresponding branch
And S500, setting a reference branch, and sequentially performing inner product operation on the reconstructed sampling signal sequence of the reference branch and the reconstructed sampling signal sequences of the other branches.
And S600, selecting a fault branch based on the inner product operation result.
According to some embodiments, if the inner product operation result of the reference branch and the certain branch is greater than zero, it indicates that the certain branch and the reference branch are of the same polarity; if the inner product operation result of the reference branch and a certain branch is less than zero, the certain branch and the reference branch are indicated to be of opposite polarities. If the reference branch and one branch are reverse polarity, the branch is a fault grounding branch; if the reference branch and all other branches are reversed polarity, the reference branch is a fault grounding branch; and if the reference branch and all other branches are in the same polarity, the bus grounding fault is detected.
According to some embodiments, based on the above embodiments, the single-phase ground line selection method further includes the following steps: acquiring zero-sequence voltage of a bus of a transformer substation and zero-sequence current signals of all branches on the bus in real time; calculating a zero-sequence voltage amplitude value based on the zero-sequence voltage; and determining the initial moment of the fault based on the fact that the zero sequence voltage amplitude exceeds a fixed value threshold.
The single-phase grounding line selection method in another embodiment of the application comprises the following steps:
step 1: acquiring zero sequence voltage of a bus of a transformer substation and zero sequence current of each branch on the bus in real time, calculating zero sequence voltage amplitude, starting a line selection working process when the zero sequence voltage exceeds a fixed value threshold, and sampling a signal sequence X by utilizing the recorded zero sequence current of each branch in a cycle wave after startingi＝[xi(1)，xi(2)，...，xi(N)]Wherein i is the serial number of each branch put into operation on the bus, L is the number of branches put into operation on the bus, i is 1,2, …, L, xi(1) The sampling point is the 1 st sampling point of the ith branch; x is the number ofi(2) The 2 nd sampling point of the ith branch is; x is the number ofiAnd (N) is the Nth sampling point of the ith branch.
Step 2: by successively intercepting corresponding sampled signal sequences Xi＝[xi(1)，xi(2)，...，xi(N)]The matrix constructed by data with equal length has the following structure:
in the formula: n is a matrix AiM is the matrix AiN is equal to N, N is equal to or greater than 2, N is equal to int (N/m), m is equal to or greater than 2; x is the number ofi(1) For branch i, the 1 st sample value, x in the sequencei(2) For branch i the 2 nd sample value, x in the sequencei(n) sampling sequence for branch iThe nth sample in the column, and so on.
And step 3: sampling signal matrix A for each branchiPerforming Singular Value Decomposition (SVD) to obtain a matrix AiR singular values σ ofi1,σi2,...,σirTo obtain a singular matrix Si＝diag(σi1,σi2,...,σir0, 0.. 0), left singular matrix UiAnd right singular matrix ViThe relationship between them is: a. thei＝UiSiVi T(ii) a Wherein σi1Is a matrix AiFirst singular value ofi2Is a matrix AiSecond singular value of σirIs a matrix AiThe r-th singular value of (a); vi TRepresenting the right singular matrix ViThe transposed matrix of (2);
according to the formula
Computing the matrix AiRoot mean square sigma of all singular valuesirmsIs greater than sigmairmsIf the number of the effective singular values is p (p is less than or equal to r), the singular matrix S is reservediSetting the other non-effective singular values in the singular matrix to zero to form a new singular matrix
p is less than or equal to r, according to
Obtaining a reconstruction matrix A 'by utilizing a singular value inverse decomposition process from left to right'i。
And 4, step 4: reconstruction matrix A'iTaking the 1 st line and the subsequent m-1 lines of elements to be connected in an end way, as shown in figure 2, the reconstructed sampling signal sequence can be spliced
Namely the filtered and de-noised sampling data.
And 5: setting a reference branch, and sequentially performing inner product operation on a reconstructed sampling signal sequence of the reference branch and reconstructed sampling signal sequences of the other branches;
reconstruction of a sequence of sampled signals using branches
Selecting a certain branch (h branch) as a reference branch, and sequentially performing inner product operation on any other branch k and the reference branch to obtain an operation result Phk. The inner product operation can be calculated as follows:
in the formula: n is the number of sampling sequence data, x'k(n) and x'h(n) the nth element in the reconstructed sample signal sequence for branch k and branch h, respectively.
Step 6: judging the polarity of inner product operation, when PhkWhen the voltage is more than 0, the k-th branch and the reference branch h have the same polarity, Phk< 0 indicates that the kth branch and the reference branch h are reversed in polarity.
If the reference branch h only has reverse polarity with a certain branch, the branch is a fault grounding branch; if all the other branches are reversed, the reference branch h is a fault grounding branch; and if all the other branches have the same polarity, the bus grounding fault is detected.
The methods presented herein are further described below in conjunction with specific applications.
Step 11: and acquiring the zero sequence voltage of the bus of the transformer substation and the zero sequence current of each branch on the bus in real time and calculating the zero sequence voltage amplitude. As shown in the attached figure 3, one line selection device is used, the bus zero-sequence voltage and the zero-sequence current of each branch are connected into the line selection device, the line selection device collects the bus zero-sequence voltage and the branch zero-sequence current in real time, and the sampling rate is 10 kHz.
Step 12: calculating to obtain zero sequence voltage amplitude value U, and when the zero sequence voltage U exceeds zero sequence voltage fixed value threshold UthIn time, sampling signal sequence X by utilizing zero sequence current of each branch within 20ms after faulti＝[xi(1)，xi(2)，...，xi(200)](ii) a Wherein i represents a branch number, i is 1,2, 3; the sampling rate is 10kHz, so the length of a 20ms sampling sequence is N-200 points, thereby constructing a branch sampling signal matrix A corresponding to each branchi。
Step 13: for each branch, sampling signal matrix AiPerforming Singular Value Decomposition (SVD) to obtain a matrix AiR singular values and a singular matrix Si＝diag(σi1,σi2,...,σir0, 0.., 0), and left singular matrix UiRight singular matrix ViThe formula is as follows:
computing the matrix AiSingular value root mean square value sigma ofirmsCalculated according to the following formula:
greater than sigmairmsIf the number of the effective singular values is p (p is less than r), the p singular values are reserved, and the rest non-effective singular values in the singular matrix are set to be zero to form a new singular matrix
By using
Obtaining a reconstruction matrix A 'through a right-left singular value inverse decomposition process'i。
Step 14: taking reconstructed matrix A'iThe elements of the 1 st line and the subsequent 7 th line are sequentially connected end to end, and the reconstructed sampling information of the branch i can be obtainedNumber sequence
Namely the filtered and noise-reduced sampling signal.
Step 15: using reconstructed sampling sequences of zero sequence currents of each branch
Selecting a certain branch as a reference branch, wherein the 3 rd branch is used as the reference branch, and the other branches 1 and 2 are respectively and sequentially subjected to inner product operation with the reference branch to obtain an operation result P31、P32The inner product operation is calculated according to the following formula:
in the formula
And filtering the noise-reduced sampling sequence for the branch k.
Step 16: p is31When > 0, it indicates that the 1 st branch and the reference branch 3 have the same polarity, P31A < 0 indicates a reverse polarity, as does the mutual polarity of branches 2, 3. Finally, judging to obtain a fault line according to the following principle: if the reference branch 3 is opposite to one of the branches 1 and 2, the fault branch is opposite to the branch 3; if the reference branch 3 and the branches 1 and 2 are both in reverse polarity, the reference branch 3 is a fault line; reference leg 3 is a bus ground fault if it is of the same polarity as legs 1, 2.
Fig. 4 shows an embodiment of a single-phase grounding line selection device, as shown in fig. 4, the device includes: a sampling signal sequence obtaining module 1001, a sampling signal matrix constructing module 1002, a reconstruction matrix module 1003, a reconstruction sampling signal sequence obtaining module 1004, an inner product operation module 1005 and a line selection module 1006, wherein:
a sampling signal sequence obtaining module 1001 for obtaining zero sequence current samples of each branch on the bus within a set time after the occurrence of the ground faultSignal sequence XiWherein i is the serial number of each branch put into operation on the bus, L is the number of branches put into operation on the bus, and i is 1,2, … and L;
a sampled signal matrix construction module 1002 for constructing a matrix based on the sampled signal sequence XiConstructing a sampling signal matrix Ai；
A reconstruction matrix module 1003 for reconstructing the sampling signal matrix aiSingular value decomposition is carried out to obtain singular matrix SiThe singular matrix SiAfter the medium and non-effective singular values are set to zero, a reconstruction matrix A 'is obtained by utilizing a singular value inverse decomposition process'i；
A reconstructed sampling signal sequence obtaining module 1004 for reconstructing the matrix A'iThe first position of each row element in the sequence is spliced to obtain a reconstructed sampling signal sequence after filtering and noise reduction of the corresponding branch
An inner product operation module 1005, configured to set a reference branch, and perform inner product operation on the reconstructed sampling signal sequence of the reference branch and the reconstructed sampling signal sequences of the remaining branches in sequence;
and a line selection module 1006, configured to select a faulty branch based on the inner product operation result.
According to some embodiments, in the sampling signal sequence acquisition module 1001, the set time is selected as a cycle duration.
According to some embodiments, the sampled signal sequence X is truncated consecutively in a sampled signal matrix construction module 1002iThe equal length data of (a) are sequentially taken as the rows of the sampling signal matrix.
According to some embodiments, in the reconstruction matrix module 1003, the sampling signal matrix a is selectediCarrying out singular value decomposition to obtain a matrix AiR singular values and a singular matrix Si＝diag(σi1,σi2,...,σir0, 0.. 0), left singular matrix UiAnd right singular matrix ViThe relationship between them is: a. thei＝UiSiVi T(ii) a Wherein，σi1Is a matrix AiFirst singular value ofi2Is a matrix AiSecond singular value of σirIs a matrix AiThe r-th singular value of (a); vi TRepresenting the right singular matrix ViThe transposed matrix of (2). Judging the validity of the singular value, if the number of the effective singular value is p (p is less than or equal to r), reserving a singular matrix SiSetting the other non-effective singular values in the singular matrix to zero to form a new singular matrix
By using
Obtaining a reconstruction matrix A 'through a right-left singular value inverse decomposition process'i。
According to some embodiments, in the line selection module 1006, according to some embodiments, if the inner product operation result of the reference branch and a certain branch is greater than zero, it indicates that the certain branch and the reference branch are of the same polarity; if the inner product operation result of the reference branch and a certain branch is less than zero, the certain branch and the reference branch are indicated to be of opposite polarities. If the reference branch and one branch are reverse polarity, the branch is a fault grounding branch; if the reference branch and all other branches are reversed polarity, the reference branch is a fault grounding branch; and if the reference branch and all other branches are in the same polarity, the bus grounding fault is detected.
FIG. 5 provides an electronic device including a processor; and a memory storing computer instructions which, when executed by the processor, cause the processor to carry out the method and refinement scheme as shown in figure 1 when executing the computer instructions.
It should be understood that the above-described device embodiments are merely exemplary, and that the devices disclosed herein may be implemented in other ways. For example, the division of the units/modules in the above embodiments is only one logical function division, and there may be another division manner in actual implementation. For example, multiple units, modules, or components may be combined, or may be integrated into another system, or some features may be omitted, or not implemented.
In addition, unless otherwise specified, each functional unit/module in each embodiment of the present invention may be integrated into one unit/module, each unit/module may exist alone physically, or two or more units/modules may be integrated together. The integrated units/modules may be implemented in the form of hardware or software program modules.
If the integrated unit/module is implemented in hardware, the hardware may be digital circuits, analog circuits, etc. Physical implementations of hardware structures include, but are not limited to, transistors, memristors, and the like. The processor or chip may be any suitable hardware processor, such as a CPU, GPU, FPGA, DSP, ASIC, etc., unless otherwise specified. Unless otherwise specified, the on-chip cache, the off-chip Memory, and the Memory may be any suitable magnetic storage medium or magneto-optical storage medium, such as resistive Random Access Memory rram (resistive Random Access Memory), Dynamic Random Access Memory dram (Dynamic Random Access Memory), Static Random Access Memory SRAM (Static Random-Access Memory), enhanced Dynamic Random Access Memory edram (enhanced Dynamic Random Access Memory), High-Bandwidth Memory HBM (High-Bandwidth Memory), hybrid Memory cubic hmc (hybrid Memory cube), and so on.
The integrated units/modules, if implemented in the form of software program modules and sold or used as a stand-alone product, may be stored in a computer readable memory. Based on such understanding, the technical solution of the present invention may be embodied in the form of a software product, which is stored in a memory and includes several instructions for causing a computer device (which may be a personal computer, a server, or a network device) to execute all or part of the steps of the method according to the embodiments of the present disclosure. And the aforementioned memory comprises: a U-disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a removable hard disk, a magnetic or optical disk, and other various media capable of storing program codes.
Embodiments of the present application also provide a non-transitory computer storage medium storing a computer program, which when executed by a plurality of processors causes the processors to perform the method and refinement scheme as shown in fig. 1.
The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be construed as the protection scope of the present invention.
Claims (10)
1. A single-phase grounding line selection method is characterized by comprising the following steps:
acquiring a zero sequence current sampling signal sequence X of each branch on a bus in a set time after a ground fault occursiWherein i is the serial number of each branch put into operation on the bus, L is the number of branches put into operation on the bus, and i is 1,2, … and L;
based on the sampling signal sequence XiConstructing a sampling signal matrix Ai；
For the sampling signal matrix AiSingular value decomposition is carried out to obtain singular matrix SiThe singular matrix SiAfter the medium and non-effective singular values are set to zero, a reconstruction matrix A 'is obtained by utilizing a singular value inverse decomposition process'i；
Reconstructing the matrix A'iThe elements in each row are spliced end to obtain a reconstructed sampling signal sequence after filtering and noise reduction of the corresponding branch
Setting a reference branch, and sequentially performing inner product operation on a reconstructed sampling signal sequence subjected to filtering and noise reduction of the reference branch and a reconstructed sampling signal sequence subjected to filtering and noise reduction of the other branches;
and selecting a fault branch based on the inner product operation result.
2. The single-phase ground line selection method of claim 1, further comprising:
acquiring zero-sequence voltage of a bus of a transformer substation and zero-sequence current signals of all branches on the bus in real time;
calculating a zero-sequence voltage amplitude value based on the zero-sequence voltage;
and determining the initial moment of the fault based on the fact that the zero sequence voltage amplitude exceeds a fixed value threshold.
3. The method of claim 1 wherein the set time is a cycle duration.
4. The single-phase ground line selection method according to claim 1, wherein the sampling signal sequence X is based oniConstructing a sampling signal matrix AiThe method specifically comprises the following steps: truncating the sequence of sampled signals X successivelyiThe equal length data of (a) are sequentially taken as the rows of the sampling signal matrix.
5. The single-phase grounding line selection method according to claim 1, wherein the method for judging the non-significant singular value comprises the following steps:
calculating the root mean square of all singular values;
and comparing each singular value with the root mean square, judging the singular value to be an effective singular value if the singular value is larger than the root mean square, and judging the singular value to be a non-effective singular value if the singular value is not larger than the root mean square.
6. The single-phase ground line selection method of claim 1, wherein the pair of the sampling signal matrix AiSingular value decomposition is carried out to obtain singular matrix SiThe singular matrix SiAfter the medium and non-effective singular values are set to zero, a reconstruction matrix A 'is obtained by utilizing a singular value inverse decomposition process'iThe method comprises the following steps:
for the sampling signal matrix AiCarrying out singular value decomposition to obtain a matrix AiR isSingular values and singular matrix Si＝diag(σi1,σi2,...,σir0, 0.. 0), left singular matrix UiAnd right singular matrix ViThe relationship between them is: a. thei＝UiSiVi T(ii) a Wherein σi1Is a matrix AiFirst singular value ofi2Is a matrix AiSecond singular value of σirIs a matrix AiThe r-th singular value of (a); vi TRepresenting the right singular matrix ViThe transposed matrix of (2);
judging the validity of the singular value, if the number of the effective singular value is p (p is less than or equal to r), reserving a singular matrix SiSetting the other non-effective singular values in the singular matrix to zero to form a new singular matrix
By using
Obtaining a reconstruction matrix A 'through a right-left singular value inverse decomposition process'i。
7. The single-phase ground line selection method according to claim 1, wherein the selecting the faulty branch based on the inner product operation result specifically includes:
if the inner product operation result of the reference branch and a certain branch is greater than zero, indicating that the certain branch and the reference branch have the same polarity; if the inner product operation result of the reference branch and a certain branch is less than zero, indicating that the certain branch and the reference branch are of opposite polarities;
if the reference branch and one branch are reverse polarity, the branch is a fault grounding branch; if the reference branch and all other branches are reversed polarity, the reference branch is a fault grounding branch; and if the reference branch and all other branches are in the same polarity, the bus grounding fault is detected.
8. A single-phase grounding line selection device is characterized by comprising:
a sampling signal sequence acquisition module for acquiring a zero sequence current sampling signal sequence X of each branch on the bus in a set time after the occurrence of the ground faultiWherein i is the serial number of each branch put into operation on the bus, L is the number of branches put into operation on the bus, and i is 1,2, … and L;
a sampling signal matrix construction module for constructing a matrix based on the sampling signal sequence XiConstructing a sampling signal matrix Ai；
A reconstruction matrix module for reconstructing the sampling signal matrix AiSingular value decomposition is carried out to obtain singular matrix SiThe singular matrix SiAfter the medium and non-effective singular values are set to zero, a reconstruction matrix A 'is obtained by utilizing a singular value inverse decomposition process'i；
A reconstruction sampling signal sequence acquisition module for acquiring the reconstruction matrix A'iThe elements in each row are spliced end to obtain a reconstructed sampling signal sequence after filtering and noise reduction of the corresponding branch
The inner product operation module is used for setting a reference branch and sequentially carrying out inner product operation on the reconstructed sampling signal sequence of the reference branch and the reconstructed sampling signal sequences of the other branches;
and the line selection module is used for selecting a fault branch based on the inner product operation result.
9. An electronic device, comprising:
a processor; and
a memory storing computer instructions that, when executed by the processor, cause the processor to perform the method of any of claims 1-7.
10. A non-transitory computer storage medium storing a computer program that, when executed by a plurality of processors, causes the processors to perform the method of any one of claims 1-7.
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