CN112114229A - Power distribution network fault positioning method, device and system - Google Patents
Power distribution network fault positioning method, device and system Download PDFInfo
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Abstract
The invention discloses a power distribution network fault positioning method, a device and a system, wherein the power distribution network fault positioning method comprises the following steps: acquiring fault transient waveforms acquired by detection points in a power distribution network line, and constructing a time-frequency matrix according to the fault transient waveforms acquired by the detection points; calculating the similarity between the time-frequency matrix and a sample time-frequency matrix in a branch sample library of the region where the detection point is located; selecting a fault line according to the time-frequency matrix similarity calculation result; and calculating the integral amplitude deviation of the acquired fault transient waveform relative to the sample fault point and the fault transient waveform at the adjacent sample fault point on the fault line, and determining the position of the fault point according to the integral amplitude deviation calculation result. The method is easy to realize, is not easily influenced by factors such as intermittent arcs and transition resistance, and can achieve the effects of improving the reliability of positioning the fault point of the power distribution network, reducing the positioning cost and the like.
Description
Technical Field
The embodiment of the invention relates to a power system fault detection technology, in particular to a power distribution network fault positioning method, device and system.
Background
The distribution network is used as the end of the power network, and the faults of the distribution network directly influence the daily life and economic activities of people due to the fact that the distribution network is directly connected with the user section. The power distribution network has a complex structure and a plurality of uncertain factors, and is the most frequent part of faults in the power system. The power failure accidents caused by the power distribution network faults account for more than 95% of the total power failure accidents, wherein 70% of the accidents are caused by single-phase ground faults or bus faults. For single-phase earth faults of a power distribution network, a reliable line fault positioning method is always lacked due to weak fault characteristic quantity. With the improvement of the requirement of people on the automation level of the power distribution network, the method has great significance for fundamentally solving the problem of fault location of the power distribution network.
At present, the commonly used power distribution network fault positioning methods at home and abroad mainly comprise an impedance method, an injection signal method and a traveling wave method. The impedance method obtains line impedance through fault point voltage and current, and therefore the fault distance is obtained; the signal injection method is to inject characteristic signals into the power distribution network and position the fault point by using a signal detection device; the traveling wave method determines the distance of a fault point according to the reflection characteristics of a wave impedance discontinuity node on a transmission line, and can be divided into a single-end method and a multi-end method in principle.
The common power distribution network fault positioning method has the following problems to be solved: first, when facing a cable overhead line hybrid line, there are two types of line wave speed scaling problems. In addition, the impedance method is susceptible to factors such as transition resistance and line branching; the reliability of the signal injection method is easily influenced by intermittent electric arcs and transition resistance; the identification of the wave head in the single-ended method is difficult, and particularly in a power distribution network with a complex topological structure, the wave head source is difficult to distinguish; the cost of the double-ended method is high. These problems are restricting further development of power systems.
Disclosure of Invention
The invention provides a power distribution network fault positioning method, device and system, which are used for improving the reliability of fault positioning in a power distribution network and quickly positioning a fault area.
In a first aspect, an embodiment of the present invention provides a power distribution network fault location method, including:
acquiring fault transient waveforms acquired by detection points in a power distribution network line, and constructing a time-frequency matrix according to the fault transient waveforms acquired by the detection points;
calculating the similarity between the time-frequency matrix and a sample time-frequency matrix in a branch sample library of the region where the detection point is located;
selecting a fault line according to the time-frequency matrix similarity calculation result;
and calculating the integral amplitude deviation of the acquired fault transient waveform relative to the sample fault point and the fault transient waveform at the adjacent sample fault point on the fault line, and determining the position of the fault point according to the integral amplitude deviation calculation result.
In a second aspect, an embodiment of the present invention provides a power distribution network fault location apparatus, including:
the waveform acquisition module is used for acquiring fault transient waveforms in the power distribution network line;
the calculation module is used for constructing a time-frequency matrix according to the fault transient waveform acquired by the waveform acquisition module, calculating the similarity between the time-frequency matrix and all sample time-frequency matrices in a branch sample library, and calculating the integral amplitude deviation of the fault transient waveform relative to a sample fault point and the fault transient waveform at an adjacent sample fault point;
and the fault positioning module is used for selecting a fault line according to the time-frequency matrix similarity calculation result and determining the position of the fault point according to the overall amplitude deviation calculation result.
In a third aspect, an embodiment of the present invention provides a power distribution network fault location system, including: the system comprises a transient signal detection device, an information collection device, a communication network, a positioning master station and an alarm terminal;
the transient signal detection device is installed on the distribution line and used for recording transient signals at the moment of line fault occurrence;
the information collecting device is in communication connection with the transient signal detection device and the fault positioning master station; processing the data collected and recorded by the transient signal detection device in the coverage area;
the power distribution network fault location device of claim 78 is integrated with the location master station.
According to the method, the position of the fault point is determined by analyzing the similarity of the fault transient waveform and the waveform in the sample library, different catadioptric wave heads are not required to be identified, the clock synchronization requirement is not required, the position of the fault point can be reliably and accurately positioned only by using single-ended information, the problems that the reliability of single-phase ground fault line selection and fault positioning in a power distribution network is low, and the fault line selection and positioning results in actual operation are inaccurate are effectively solved, and the effects of high reliability, easiness in implementation and low cost of fault point positioning are achieved.
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Fig. 1 is a flowchart of a power distribution network fault location method according to a first embodiment of the present invention;
fig. 2 is a diagram of a model of a 10kV distribution network according to a first embodiment of the present invention;
fig. 3 is a flowchart of a power distribution network fault location method according to a second embodiment of the present invention;
fig. 4 is a schematic structural diagram of a power distribution network fault location device provided in the third embodiment of the present invention;
fig. 5 is a schematic diagram of a power distribution network fault location system in a fourth embodiment of the present invention.
Detailed Description
The present invention will be described in further detail with reference to the accompanying drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the invention and are not limiting of the invention. It should be further noted that, for the convenience of description, only some of the structures related to the present invention are shown in the drawings, not all of the structures.
In order to make the technical solutions of the present invention better understood, the technical solutions in the embodiments of the present invention are clearly and completely described below, 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.
Example one
Fig. 1 is a flowchart of a power distribution network fault location method according to an embodiment of the present invention, where this embodiment may be used in a situation where a single-phase ground fault occurs in a power distribution network, and the method may be executed by a power distribution network fault location device, and specifically includes the following steps:
the detection points are branch nodes of a power distribution network provided with a transient signal detection device; the fault transient waveform is a transient waveform collected by a transient signal detection device of a detection point when the power distribution network has a fault, and can be acquired by carrying out wireless communication with the transient signal detection device.
For example, when an actual fault occurs, a transient signal device on a detection point triggers a wave recording function, a fault transient signal at the line fault occurrence moment is recorded, S transformation is performed on discrete signal points of the transient signal to obtain a two-dimensional matrix related to the S transformation, amplitude vectors under each frequency obtained after the S transformation are subdivided, each frequency is provided with N sampling points and is equally divided into M blocks, and amplitudes corresponding to each frequency and time interval are calculated to form a time-frequency matrix.
the branch sample library is formed by collecting transient state waveforms of sample fault points of all branches in each area at detection points of each area, uploading the transient state waveforms to a positioning master station, and constructing a time-frequency matrix to form the branch sample library of the area; the similarity is used for describing the similarity of two fault transient waveforms;
specifically, the similarity between the time-frequency matrix of the fault point and all the sample time-frequency matrices in the branch sample library of the region is calculated, and the similarity ρ between the two fault transient waveform time-frequency matrices a1 and a2 is:
wherein the content of the first and second substances,<A1,A2>representing a matrix time-frequency matrix A1And a time-frequency matrix A2Inner product of (d); | | A1||、||A2Respectively represent the matrix A1And A2Norm of (d); analogous to the vector angle, γ is defined as the angle between 2 matrices: when γ is 90 °, ρ is 0, indicating that 2 matrices are completely different; when γ is 0 °, ρ is 1, which means that 2 matrices have extremely high similarity.
specifically, the fault branch is judged according to the time-frequency matrix similarity calculation result, and the specific criterion is as follows: rhomax＞ρsetTime, rhomaxThe branch of the corresponding sample fault point is a fault line rhomaxThe maximum similarity between the fault transient waveform and the sample fault transient waveform in the branch sample library is the maximum value of the similarity between the fault transient waveform and the sample fault transient waveform in the branch sample library; rhosetA threshold value set for reliable discrimination of a faulty branch.
Exemplarily, please refer to fig. 2, fig. 2 is a model diagram of a 10kV distribution network, in which a-F represent the ends of each line, T1～T4Representing each branch node, T1T3And DT2The cable line is adopted, and the rest is an overhead line. AT branch1Upper distance T1Single-phase earth faults f are respectively arranged at the positions of 0.2, 0.6 and 3km1，f3And f4At branch BT1Upper distanceFrom T1Setting single-phase earth fault f at 0.2km position of node2。
Fault f1After the occurrence, the 1 st traveling wave detected by the A end is directly transmitted to the A end from a fault point; the 2 nd traveling wave is propagated from the fault point to the branch node T1And at T1The part is reflected, then is refracted at a fault point, and finally reaches the end A; the 3 rd traveling wave is reflected once at the A end and the fault point respectively and finally reaches the A end. For a certain detection point, the detected transient signal is the superposition of each secondary traveling wave according to a certain time sequence after the fault initial traveling wave is refracted and reflected at the discontinuous place of the wave impedance. Therefore, the fault f detected by the A end can be known1Voltage reverse wave
And the traveling wave
Respectively, as shown in the following formula.
Wherein E is1Is an initial traveling wave; q is a transfer function; k and H are respectively the refractive index and the reflection coefficient of the fault traveling wave at the discontinuous point of the wave impedance; the subscripts of Q, K, H denote the transmission path of the fault travelling wave.
In the same way, failure f2After the occurrence, the voltage direction traveling wave detected by the A end has the same value as
Similar expressions, but because the refraction and reflection conditions, transmission paths and arrival time sequences of the secondary traveling waves are different, the superposition terms in the expressions are different.
For faults at different positions on the same branch, the analysis is easy to know that the travelling waves have the same refraction and reflection conditions, but the transmission functions and the arrival time sequences are different, so that fault transient waveforms are different. This difference will be drastically reduced for faults where the fault point location is very close. Therefore, the similarity of the transient waveforms when faults are at different positions can be utilized to realize the judgment of the fault branch and the accurate positioning of the fault point in the power distribution network.
specifically, the method for determining the position of the fault point according to the calculation result of the integral amplitude deviation mainly calculates and obtains the accurate position of the fault point by utilizing the proportional relation between the integral amplitude deviation and the position of the fault point, and comprises the following steps: in the step 140, in the fault line determination process, the similarity between the fault transient waveform and all the sample fault transient waveforms in the branch sample library is obtained, and the sample fault point Y with the maximum similarity value is determinedn(ii) a Defining the amplitude deviation of the ith sampling point between the waveform a and the waveform b as:a-b,i＝|ai-bii, in which aiAnd biThe amplitude values of the ith sampling points of the waveform a and the waveform b respectively are calculated, and then the fault transient waveform and the sample fault point Y are calculatednAnd adjacent sample failure point Yn-1And Yn+1The overall amplitude deviation of the fault transient waveform is as follows:
and
selecting two sample fault points with the minimum integral amplitude deviation, wherein the fault point is positioned between the two sample fault points; calculating the distance from the fault point to the sample fault point with the minimum integral amplitude deviation:
wherein
Is the distance, X, between two sample failure points with small deviation of the overall amplitudeminIs the smallest value among the overall amplitude deviations, XmidThe second smallest value in the overall amplitude deviation. According to the technical scheme, the specific position of the fault point is determined by analyzing the similarity and the integral amplitude deviation of the fault transient waveform and the sample fault transient waveform in the branch sample library, the method is not affected by system parameters, transition resistance and other factors, the fault point of the power distribution network is accurately positioned, and the effects of reliable and accurate positioning are achieved.
Example two
Optionally, referring to fig. 3, another power distribution network fault location method provided by the present invention adds, on the basis of the first embodiment, settings for the detection points and the regional branch sample library, and the method specifically includes:
Specifically, a transient signal detection device is arranged according to the topological structure of the power distribution network, and the transient signal detection device is configured on a limited number of branch nodes according to the principle that an initial transient signal reaches a detection point and passes through at most one branch node when a fault occurs at any position.
Optionally, step 220, setting sample fault points on each branch line of the power distribution network according to preset intervals;
specifically, sample fault points are set at preset intervals on each line in the power distribution network.
Optionally, step 230, a fault transient waveform when a fault occurs in a sample fault point of each branch in the region is collected by using the detection point, and a time-frequency matrix is constructed to form a branch sample library in the region.
In particular, the amount of the solvent to be used,each detection point and the nearest branch form a fault discrimination area, wherein the distance between the branch in one fault discrimination area and the detection point does not exceed one branch node. Sample fault points are arranged on each branch line of the power distribution network at preset intervals, the detection points of each area collect the transient state waveforms of the sample fault points of each branch of the area and upload the transient state waveforms to a positioning main station, and then a time-frequency matrix is constructed to form a branch sample library of the area. The method for constructing the time-frequency matrix comprises the following steps: for discrete signal points x [ k ] of transient waveform](k-0, 1, …, N-1) performing an S-transform and deriving a two-dimensional matrix associated with the S-transform; subdividing the amplitude vector under each frequency obtained after S conversion, wherein each frequency has N sampling points, equally dividing the frequency into M blocks, and the amplitude corresponding to the g-th time period block under the j-th frequency is
The time-frequency matrix E reflecting the transient signal is as follows:
optionally, step 240, obtaining a fault transient waveform collected by a detection point in the power distribution network line, and constructing a time-frequency matrix according to the fault transient waveform collected by the detection point.
Specifically, the detection point collects the electric quantity signals of the line operation, when the line is in fault, the wave recording function is triggered, the transient waveform of the line fault at the moment is recorded, then a time-frequency matrix is constructed, and discrete signal points x [ k ] of the transient waveform are subjected to discrete signal processing](k-0, 1, …, N-1) performing an S-transform and deriving a two-dimensional matrix associated with the S-transform; subdividing the amplitude vector under each frequency obtained after S conversion, wherein each frequency has N sampling points, equally dividing the frequency into M blocks, and the amplitude corresponding to the g-th time period block under the j-th frequency is
The time-frequency matrix E reflecting the transient signal is as follows:
optionally, step 250, calculating the similarity between the time-frequency matrix and the sample time-frequency matrix in the branch sample library of the region where the detection point is located.
Specifically, the similarity rho between the time-frequency matrix of the fault transient waveform and the time-frequency matrix of the sample fault transient waveform in the branch sample library of the region where the detection point is located is calculated,
gamma is the included angle between 2 matrixes; when γ is 90 °, ρ is 0, indicating that 2 matrices are completely different; when γ is 0 °, ρ is 1, which means that 2 matrices have extremely high similarity.
Optionally, in step 260, a faulty line is selected according to the time-frequency matrix similarity calculation result.
Specifically, the fault branch is judged according to the time-frequency matrix similarity calculation result, and the specific criterion is as follows:
ρmax＞ρset，ρmaxthe maximum similarity between the fault transient waveform and the branch sample library is the maximum value of the similarity between the fault transient waveform and the sample fault transient waveform in the branch sample library; rhosetA threshold value set for reliable discrimination of a faulty branch. When the fault transient waveform and the maximum value rho of the similarity of the sample fault transient waveforms in the sample librarymaxGreater than a threshold value rhosetAnd if so, the branch line corresponding to the sample fault transient waveform is a fault line.
Optionally, step 270, in the fault line, an overall amplitude deviation of the acquired fault transient waveform with respect to the sample fault point and the fault transient waveform at the adjacent sample fault point is calculated, and a fault point position is determined according to an overall amplitude deviation calculation result.
Specifically, the sample fault point Y with the maximum similarity value is determined through the similarityn(ii) a Defining the amplitude deviation of the ith sampling point between the waveform a and the waveform b as:a-b,i＝|ai-biin the formula: a isiAnd biIth of waveform a and waveform b respectivelySampling point amplitude, calculating the actual fault transient waveform and the sample fault point YnAnd adjacent sample failure point Yn-1And Yn+1The integral amplitude deviation of the fault transient waveform is
And
selecting two sample fault points with the minimum integral amplitude deviation, wherein the fault point is positioned between the two sample fault points; calculating the distance from the fault point to the sample fault point with the minimum integral amplitude deviation:
wherein the content of the first and second substances,
is the distance, X, between two sample failure points with small deviation of the overall amplitudeminIs the smallest value among the overall amplitude deviations, XmidThe second smallest value in the overall amplitude deviation.
According to the method, the number of detection devices is reduced by scientifically setting the detection points, the area branch sample library is established, so that subsequent fault location is more convenient, the cost input of the power distribution network fault location method is reduced, the fault location efficiency is improved, and the effects of good economy and high efficiency can be achieved.
EXAMPLE III
Optionally, a schematic structural diagram of a power distribution network fault locating device shown in fig. 4 is suitable for implementing power distribution network fault locating, and the device includes:
the waveform acquiring module 310 is configured to acquire a fault transient waveform in a power distribution network line;
a calculating module 320, configured to construct a time-frequency matrix according to the fault transient waveform obtained by the waveform obtaining module, calculate similarities between the time-frequency matrix and time-frequency matrices of all samples in the branch sample library, and calculate an overall amplitude deviation of the fault transient waveform with respect to a sample fault point and a fault transient waveform at an adjacent sample fault point;
and the fault positioning module 330 is configured to select a fault line according to the time-frequency matrix similarity calculation result, and determine a position of the fault point according to the overall amplitude deviation calculation result.
The device can accurately position the fault point of the power distribution network by acquiring and calculating the fault transient waveform, and achieves the effect of reliable and accurate positioning.
Optionally, the power distribution network fault location device may further include:
the detection point setting module 340 is used for installing transient signal detection devices in the power distribution network before the waveform acquisition module, wherein each detection device is installed with one detection point, and the positions of the detection points meet the principle that a signal at any position reaches the detection point and passes through at most one branch node, so that the limited transient signal detection devices are configured;
and the sample library construction module 350 is used for setting sample fault points in the power distribution network after the point setting module is detected, acquiring fault transient waveforms when the sample fault points of each branch in the area have faults by using the detected points, and constructing a time-frequency matrix to form a branch sample library in the area.
The product can execute the method provided by any embodiment of the invention, and has corresponding functional modules and beneficial effects of the execution method.
Example four
Optionally, fig. 5 is a schematic structural diagram of a power distribution network fault location system, which is suitable for implementing power distribution network fault location, and the system includes: the system comprises a transient signal detection device 410, an information collection device 420, a communication network 430, a positioning master station 440 and an alarm terminal 450;
the transient signal detection device 410 is installed on a distribution line and used for recording a transient signal at the time of line fault occurrence;
the information collecting device 420 is in communication connection with the transient signal detection device 410 and the fault locating master station 440; processing the data collected and recorded by the transient signal detection device 410 in the coverage area;
the positioning master station 440 is integrated with the power distribution network fault positioning device described in the third embodiment, and is configured to send monitored line operation information and fault alarm information to the alarm terminal 450.
Specifically, the transient signal detection device 410 is installed on a distribution line, and is used for collecting an electrical quantity signal of a line operation, and when the line fails, the transient signal detection device 410 triggers a wave recording function to record a transient signal at the time of the line failure; the communication network 430 may include a LoRa/WIFI short-range communication network between the transient signal detection device 410 and the information aggregation device 420, and a 4G/5G/optical fiber long-range communication network between the information aggregation device 420 and the positioning master station 440, and between the positioning master station 440 and the alarm terminal 450; the positioning master station 440 executes the fault positioning method provided by any embodiment of the invention according to the data uploaded by the information collecting device 420, completes data analysis processes such as matrix similarity calculation, integral amplitude deviation calculation and the like, and completes fault line selection and fault positioning research and judgment; the alarm terminal 450 may be a terminal of a device such as a mobile phone, a tablet, a computer, etc. capable of networking, and the alarm terminal 450 may query the monitored line operation information and the alarm information such as fault line selection and location during fault in real time.
It is to be noted that the foregoing is only illustrative of the preferred embodiments of the present invention and the technical principles employed. It will be understood by those skilled in the art that the present invention is not limited to the particular embodiments described herein, but is capable of various obvious changes, rearrangements and substitutions as will now become apparent to those skilled in the art without departing from the scope of the invention. Therefore, although the present invention has been described in greater detail by the above embodiments, the present invention is not limited to the above embodiments, and may include other equivalent embodiments without departing from the spirit of the present invention, and the scope of the present invention is determined by the scope of the appended claims.
Claims (10)
1. A power distribution network fault positioning method is characterized by comprising the following steps:
acquiring fault transient waveforms acquired by detection points in a power distribution network line, and constructing a time-frequency matrix according to the fault transient waveforms acquired by the detection points;
calculating the similarity between the time-frequency matrix and a sample time-frequency matrix in a branch sample library of the region where the detection point is located;
selecting a fault line according to the time-frequency matrix similarity calculation result;
and calculating the integral amplitude deviation of the acquired fault transient waveform relative to the sample fault point and the fault transient waveform at the adjacent sample fault point on the fault line, and determining the position of the fault point according to the integral amplitude deviation calculation result.
2. The power distribution network fault location method according to claim 1, wherein before acquiring the fault transient waveform collected by the detection point in the power distribution network line, the method further comprises:
setting sample fault points on each branch line of the power distribution network according to preset intervals;
and acquiring fault transient waveforms when the sample fault points of each branch of the region have faults by using the detection points, and constructing a time-frequency matrix to form a branch sample library of the region.
3. The power distribution network fault location method according to claim 2, wherein before setting sample fault points on each branch line of the power distribution network at preset intervals, the method further comprises:
and arranging transient signal detection devices according to the topological structure of the power distribution network, wherein each detection device is provided with one detection point, and the positions of the detection points meet the principle that signals at any positions reach the detection points and pass through at most one branch node, so that the limited transient signal detection devices are configured.
4. The method for locating the fault in the power distribution network according to claim 1, wherein the calculating the similarity between the time-frequency matrix and the sample time-frequency matrix in the branch sample library of the area where the detection point is located includes:
performing S transformation on discrete signal points x [ k ] (k is 0, 1, …, N-1) of the transient signal and obtaining a two-dimensional matrix related to the S transformation;
subdividing the amplitude vector under each frequency obtained after S conversion, wherein each frequency has N sampling points, equally dividing the frequency into M blocks, and the amplitude corresponding to the g-th time period block under the j-th frequency is
The time-frequency matrix E reflecting the transient signal is as follows:
calculating the similarity rho between two fault transient waveform time-frequency matrixes by the following formula:
wherein the content of the first and second substances,<A1,A2>representing a matrix time-frequency matrix A1And a time-frequency matrix A2Inner product of (d); | | A1||、||A2Respectively represent the matrix A1And A2Norm of (d).
5. The power distribution network fault location method of claim 1, wherein the selecting of the fault line according to the time-frequency matrix similarity calculation result comprises:
when the fault transient waveform and the maximum value rho of the similarity of the sample fault transient waveforms in the sample librarymaxGreater than a threshold value rhosetAnd if so, the branch line corresponding to the sample fault transient waveform is a fault line.
6. The method according to claim 3, wherein the step of calculating, at the fault line, an overall amplitude deviation of the collected fault transient waveform with respect to the sample fault point and the fault transient waveform at the adjacent sample fault point, and determining the fault point position according to the overall amplitude deviation calculation result includes:
determining the sample fault point Y with the maximum similarity value through the similarityn；
Calculating the actual fault transient waveform and the sample fault point YnAnd adjacent sample failure point Yn-1And Yn+1Integral amplitude deviation of fault transient waveform
And
selecting two sample fault points with the minimum integral amplitude deviation, wherein the fault point is positioned between the two sample fault points;
calculating the distance from the fault point to the sample fault point with the minimum integral amplitude deviation:
wherein
Is the distance, X, between two sample failure points with small deviation of the overall amplitudeminIs the smallest value among the overall amplitude deviations, XmidThe second smallest value in the overall amplitude deviation.
7. A distribution network fault locating device, characterized by includes:
the waveform acquisition module is used for acquiring fault transient waveforms in the power distribution network line;
the calculation module is used for constructing a time-frequency matrix according to the fault transient waveform acquired by the waveform acquisition module, calculating the similarity between the time-frequency matrix and all sample time-frequency matrices in a branch sample library, and calculating the integral amplitude deviation of the fault transient waveform relative to a sample fault point and the fault transient waveform at an adjacent sample fault point;
and the fault positioning module is used for selecting a fault line according to the time-frequency matrix similarity calculation result and determining the position of the fault point according to the overall amplitude deviation calculation result.
8. The power distribution network fault locating device of claim 7, further comprising:
the detection point setting module is used for installing transient signal detection devices in the power distribution network before the waveform acquisition module, wherein each detection device is installed with one detection point, and the positions of the detection points meet the principle that a signal at any position reaches the detection points and passes through at most one branch node;
and the sample library construction module is used for setting sample fault points in the power distribution network after the detection point setting module is detected, acquiring fault transient waveforms when the sample fault points of each branch of the region have faults by using the detection points, and constructing a time-frequency matrix to form a branch sample library of the region.
9. A power distribution network fault location system, comprising: the system comprises a transient signal detection device, an information collection device, a communication network, a positioning master station and an alarm terminal;
the transient signal detection device is installed on the distribution line and used for recording transient signals at the moment of line fault occurrence;
the information collecting device is in communication connection with the transient signal detection device and the fault positioning master station; processing the data collected and recorded by the transient signal detection device in the coverage area;
the positioning master station is integrated with the power distribution network fault positioning device of claim 8.
10. The system of claim 9, further comprising the alarm terminal, wherein the positioning master station is configured to send monitored line operation information and fault alarm information to the alarm terminal.
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