CN113433424B - Distribution network line tree falling detection method and system based on partial discharge - Google Patents
Distribution network line tree falling detection method and system based on partial discharge Download PDFInfo
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- G01R31/12—Testing dielectric strength or breakdown voltage ; Testing or monitoring effectiveness or level of insulation, e.g. of a cable or of an apparatus, for example using partial discharge measurements; Electrostatic testing
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- G01R31/1263—Testing dielectric strength or breakdown voltage ; Testing or monitoring effectiveness or level of insulation, e.g. of a cable or of an apparatus, for example using partial discharge measurements; Electrostatic testing of components, parts or materials of solid or fluid materials, e.g. insulation films, bulk material; of semiconductors or LV electronic components or parts; of cable, line or wire insulation
- G01R31/1272—Testing dielectric strength or breakdown voltage ; Testing or monitoring effectiveness or level of insulation, e.g. of a cable or of an apparatus, for example using partial discharge measurements; Electrostatic testing of components, parts or materials of solid or fluid materials, e.g. insulation films, bulk material; of semiconductors or LV electronic components or parts; of cable, line or wire insulation of cable, line or wire insulation, e.g. using partial discharge measurements
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Abstract
The application discloses a distribution network line tree falling detection method and system based on partial discharge, by acquiring a target signal containing a partial discharge signal and an interference signal around a power transmission line surrounded by trees, carrying out gradient on the target signal to enhance the difference between the amplitude of the partial discharge signal and the amplitude of the interference signal, then removing the interference signal in the target signal by utilizing a z-score standard score and a clustering method, dividing a signal amplitude sample in a second correction signal with interference signals removed into a plurality of clusters by using a cluster clustering method, determining whether non-zero partial discharge exists in the clusters or not according to the length from each cluster to a clustering center, namely determining that the non-zero partial discharge exists in the power transmission line, wherein the non-zero partial discharge indicates that trees fall to the power transmission line to generate the non-zero partial discharge, therefore, the technical problem that the high-impedance fault caused by the falling of the trees in the distribution network line is difficult to detect is solved.
Description
Technical Field
The application relates to the technical field of distribution network line detection, in particular to a distribution network line tree falling detection method and system based on partial discharge.
Background
The biggest disadvantage of using insulated wires in power transmission lines, especially medium voltage overhead lines, is that high impedance faults are difficult to detect. When trees near a distribution network line fall, the surface of an insulated conductor is in direct contact with tree vegetation around the conductor, and due to different potentials, a fault current from the conductor to the tree vegetation can be generated. In the long run, this partial discharge activity will lead to insulation failure, resulting in short-circuit connections and earth faults, which must be detected and discovered in time.
Therefore, a simple and reliable method for detecting tree falling of a distribution network line is urgently needed.
Disclosure of Invention
The application provides a distribution network line tree falling detection method and system based on partial discharge, which are used for solving the technical problem that a high-impedance fault caused by tree falling of a distribution network line is difficult to detect.
In view of this, the first aspect of the present application provides a distribution network line tree falling detection method based on partial discharge, which is applied to a power transmission line surrounded by trees, and includes the following steps:
s1, acquiring target signals around the power transmission line according to a preset sampling period, wherein the target signals in each sampling period comprise a plurality of signal amplitude samples, and the target signals comprise partial discharge signals and interference signals;
s2, carrying out gradient on the target signal to obtain a gradient signal, so as to enhance the difference between the amplitude of the partial discharge signal and the amplitude of the interference signal;
s3, calculating a z-score standard score of each signal amplitude sample in the gradient signal, judging whether the z-score standard score is larger than a preset z-score standard score threshold value, if so, rejecting the corresponding signal amplitude sample in the gradient signal, and if not, retaining the corresponding signal amplitude sample so as to transform the gradient signal into a first correction signal;
s4, analyzing the first correction signal based on a cluster clustering method, so as to eliminate random pulse interference signals in the first correction signal, and obtain a second correction signal;
s5, clustering and dividing the signal amplitude samples in the second correction signal into a plurality of clusters based on a cluster clustering method, calculating the length from each cluster to a clustering center, judging whether the length from each cluster to the clustering center is larger than a preset length threshold value, and if so, determining that the non-zero partial discharge exists in the power transmission line.
Preferably, step S1 specifically includes:
the method comprises the steps that target signals around the power transmission line are obtained according to preset sampling periods based on radio frequency antenna receiving equipment, the target signals in each sampling period comprise a plurality of signal amplitude samples, the target signals comprise partial discharge signals and interference signals, and the interference signals comprise narrow-band interference signals and random pulse interference signals.
Preferably, step S2 specifically includes:
determining the extreme point amplitude of a signal amplitude sample in the target signal, calculating the gradient between every two adjacent extreme point amplitudes, and carrying out gradient processing on the target signal according to the gradient to obtain a gradient signal, so that the ratio of the amplitude of the partial discharge signal to the amplitude of the interference signal is enhanced.
Preferably, step S4 specifically includes:
s401, acquiring a non-zero amplitude value in sample signal amplitude values in the first correction signal;
s402, calculating the distance between every two adjacent non-zero amplitudes;
and S403, judging whether the distance between every two adjacent nonzero amplitudes is smaller than a preset distance threshold, and if the distance between every two adjacent nonzero amplitudes is smaller than the preset distance threshold, clustering signal amplitude samples corresponding to the adjacent nonzero amplitudes into a same cluster so as to eliminate random pulse interference signals and obtain a second correction signal.
Preferably, step S5 is followed by:
and S6, sending fault early warning information to a power grid maintenance center according to the non-zero partial discharge, wherein the fault early warning information comprises the non-zero partial discharge information and the position information of the power transmission line corresponding to the non-zero partial discharge information.
In a second aspect, the present invention further provides a system for detecting tree falling in a distribution network line based on partial discharge, including:
the acquisition module is used for acquiring target signals around the power transmission line according to preset sampling periods, wherein the target signals in each sampling period comprise a plurality of signal amplitude samples, and the target signals comprise partial discharge signals and interference signals;
the gradient module is used for carrying out gradient on the target signal to obtain a gradient signal so as to enhance the difference between the amplitude of the partial discharge signal and the amplitude of the interference signal;
a first modification module, configured to calculate a z-score criterion score of each signal amplitude sample in the gradient signal, further configured to determine whether the z-score criterion score is greater than a preset z-score criterion score threshold, further configured to reject the corresponding signal amplitude sample from the gradient signal when the z-score criterion score is greater than the preset z-score criterion score threshold, and further configured to retain the corresponding signal amplitude sample when the z-score criterion score is not greater than the preset z-score criterion score threshold, so as to transform the gradient signal into a first modified signal;
the second correction module is used for analyzing the first correction signal based on a cluster clustering method so as to eliminate random pulse interference signals in the first correction signal to obtain a second correction signal;
and the non-zero judgment module is used for clustering and dividing the signal amplitude samples in the second correction signal into a plurality of clusters based on a cluster clustering method, calculating the length from each cluster to a clustering center, judging whether the length from each cluster to the clustering center is greater than a preset length threshold value, and determining that the non-zero partial discharge exists in the power transmission line when the length from each cluster to the clustering center is greater than the preset length threshold value.
Preferably, the gradient module comprises a determination sub-module, a gradient calculation sub-module and a gradient sub-module;
the determining submodule is used for determining the extreme point amplitude of a signal amplitude sample in the target signal;
the gradiometer module is used for calculating the gradient between the amplitudes of every two adjacent extreme points;
the gradient submodule is used for carrying out gradient on the target signal according to the gradient to obtain a gradient signal, so that the ratio of the amplitude of the partial discharge signal to the amplitude of the interference signal is enhanced.
Preferably, the second correction module comprises a non-zero amplitude submodule, a distance calculation submodule and a distance judgment submodule;
the non-zero amplitude submodule is used for acquiring a non-zero amplitude in the sample signal amplitudes in the first correction signal;
the distance calculation submodule is used for calculating the distance between every two adjacent non-zero amplitudes;
the distance judgment submodule is used for judging whether the distance between every two adjacent nonzero amplitudes is smaller than a preset distance threshold value or not, and is also used for clustering signal amplitude samples corresponding to the adjacent nonzero amplitudes into a same cluster when the distance between the adjacent nonzero amplitudes is smaller than the preset distance threshold value, so that random pulse interference signals are eliminated, and a second correction signal is obtained.
Preferably, the system further comprises: the device comprises a positioning module and a sending module;
the positioning module is used for acquiring the position information of the power transmission line corresponding to the non-zero partial discharge;
and the sending module is used for sending fault early warning information to a power grid maintenance center according to the non-zero partial discharge, wherein the fault early warning information comprises the non-zero partial discharge information and the position information of the power transmission line corresponding to the non-zero partial discharge information.
According to the technical scheme, the invention has the following advantages:
the invention obtains the target signal containing the partial discharge signal and the interference signal around the power transmission line surrounded by the trees, the target signal is graded to enhance the difference between the amplitude of the partial discharge signal and the amplitude of the interference signal, so as to filter the interference signals subsequently, and then eliminate the interference signals in the target signals by using the z-score standard score and clustering method, dividing a signal amplitude sample in a second correction signal with interference signals removed into a plurality of clusters by using a cluster clustering method, determining whether non-zero partial discharge exists in the clusters or not according to the length from each cluster to a clustering center, namely determining that the non-zero partial discharge exists in the power transmission line, wherein the non-zero partial discharge indicates that trees fall to the power transmission line to generate the non-zero partial discharge, therefore, the technical problem that the high-impedance fault caused by the falling of the trees in the distribution network line is difficult to detect is solved.
Drawings
Fig. 1 is a flowchart of a method for detecting tree falling in a distribution network line based on partial discharge according to an embodiment of the present disclosure;
fig. 2 is a schematic structural diagram of a system for detecting tree falling in a distribution network line based on partial discharge provided in an embodiment of the present application.
Detailed Description
In order to make those skilled in the art better understand the technical solutions of the present application, 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 only a part of the embodiments of the present application, and not all 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 application.
When trees near a distribution network line fall, the surface of an insulated conductor is in direct contact with tree vegetation around the conductor, and due to different potentials, a fault current from the conductor to the tree vegetation can be generated. In the long run, this partial discharge activity will lead to insulation failure, resulting in short-circuit connections and earth faults, which must be detected and discovered in time.
For convenience of understanding, please refer to fig. 1, the method for detecting tree falling of a distribution network line based on partial discharge provided by the present application is applied to a power transmission line surrounded by trees, and includes the following steps:
s1, acquiring target signals around the power transmission line according to a preset sampling period, wherein the target signals in each sampling period comprise a plurality of signal amplitude samples, and the target signals comprise partial discharge signals and interference signals;
s2, carrying out gradient on the target signal to obtain a gradient signal, so as to enhance the difference between the amplitude of the partial discharge signal and the amplitude of the interference signal;
s3, calculating a z-score standard score of each signal amplitude sample in the gradient signal, judging whether the z-score standard score is larger than a preset z-score standard score threshold value, if so, rejecting the corresponding signal amplitude sample in the gradient signal, and if not, retaining the corresponding signal amplitude sample so as to transform the gradient signal into a first correction signal;
s4, analyzing the first correction signal based on a cluster clustering method, and thus eliminating random pulse interference signals in the first correction signal to obtain a second correction signal;
s5, clustering and dividing the signal amplitude samples in the second correction signal into a plurality of clusters based on a cluster clustering method, calculating the length from each cluster to a clustering center, judging whether the length from each cluster to the clustering center is larger than a preset length threshold value, and if so, determining that the non-zero partial discharge exists in the power transmission line.
In this embodiment, by acquiring a target signal including a partial discharge signal and an interference signal around a transmission line surrounded by trees, the target signal is graded to enhance the differentiation between the amplitude of the partial discharge signal and the amplitude of the interference signal, so as to filter the interference signals subsequently, and then eliminate the interference signals in the target signals by using a z-score standard score and a clustering method, dividing a signal amplitude sample in a second correction signal with interference signals removed into a plurality of clusters by using a cluster clustering method, determining whether non-zero partial discharge exists in the clusters or not according to the length from each cluster to a clustering center, namely determining that the non-zero partial discharge exists in the power transmission line, wherein the non-zero partial discharge indicates that trees fall to the power transmission line to generate the non-zero partial discharge, therefore, the technical problem that the high-impedance fault caused by the falling of the trees in the distribution network line is difficult to detect is solved.
The following is a detailed description of an embodiment of the distribution network line tree falling detection method based on partial discharge provided by the invention.
S100, target signals around the power transmission line are obtained according to a preset sampling period based on radio frequency antenna receiving equipment, the target signals in each sampling period comprise a plurality of signal amplitude samples, the target signals comprise partial discharge signals and interference signals, and the interference signals comprise narrow-band interference signals and random pulse interference signals.
In this embodiment, radio frequency antenna receiving equipment is installed at a power transmission line with dense surrounding vegetation, so as to receive a target signal around the power transmission line, where a preset sampling period is 20ms, and the target signal in each sampling period includes 400000 signal amplitude samples.
The target signal may contain a partial discharge signal which is 0 when being acquired, that is, a partial discharge phenomenon is not generated, and the interference signal includes a narrowband interference signal and a random impulse interference signal, wherein a main source of the narrowband interference signal is a wireless signal transmitted by a surrounding radio broadcast transmitter, and the random impulse interference signal is mainly caused by lightning, a switching operation or a discharge. The radio frequency antenna receiving equipment can effectively receive the electromagnetic waves generated by partial discharge and other reasons, so that the radio frequency antenna receiving equipment can be adopted to obtain partial discharge signals and interference signals around the power transmission line.
S200, determining the extreme point amplitude of a signal amplitude sample in the target signal, calculating the gradient between every two adjacent extreme point amplitudes, and carrying out gradient processing on the target signal according to the gradient to obtain a gradient signal, so that the ratio of the amplitude of the partial discharge signal to the amplitude of the interference signal is enhanced.
It should be noted that, in this embodiment, the extreme point amplitude is first found out of 400000 signal amplitude samples, where the extreme point amplitude includes the highest amplitude and the lowest amplitude, and an ascending trend and a descending trend occur in 400000 signal amplitude samples, and the point with the lowest amplitude in the descending trend is the lowest amplitude, and the point with the highest amplitude in the ascending trend is the highest amplitude.
After finding the extreme point amplitude values in the 400000 signal amplitude samples, the gradient between two adjacent extreme points is calculated by the formula,
in which x represents a gradient, wfRepresenting the extreme point, w, corresponding to the f-th signal amplitude samplelIndicating the extreme point corresponding to the ith signal amplitude sample.
After the gradient is obtained through calculation, the target signal is subjected to gradient to obtain a gradient signal, so that the ratio of the amplitude of the partial discharge signal to the amplitude of the interference signal is enhanced, namely differentiation is achieved.
S300, calculating a z-score standard score of each signal amplitude sample in the gradient signal, judging whether the z-score standard score is larger than a preset z-score standard score threshold value, if so, rejecting the corresponding signal amplitude sample in the gradient signal, and if not, retaining the corresponding signal amplitude sample so as to convert the gradient signal into a first correction signal;
it should be noted that the z-score standard score for each signal magnitude sample is calculated by,
in the formula, xiDenotes the amplitude of the i-th signal amplitude sample, μ denotes the average value of the amplitudes of the gradient signals, and σ denotes the standard deviation of the amplitudes of the gradient signals.
For normal distribution, the maximum value of z-score is usually less than 3, the z-score standard score threshold is set to a value greater than 3 according to historical experience, the z-score standard score of each signal amplitude sample is compared with a preset z-score standard score threshold, and if the z-score standard score is greater than the preset z-score standard score threshold, the signal amplitude sample belongs to a narrow-band interference signal and needs to be removed from the gradient signal.
S400, analyzing the first correction signal based on a cluster clustering method, so as to eliminate random pulse interference signals in the first correction signal, and obtain a second correction signal;
specifically, step S400 specifically includes:
s401, acquiring a non-zero amplitude value in the sample signal amplitude values in the first correction signal;
s402, calculating the distance between every two adjacent non-zero amplitudes;
wherein the calculation formula for calculating the distance between every two adjacent non-zero amplitudes is as follows,
in the formula (d)fgRepresenting the distance between the f-th non-zero amplitude and the g-th non-zero amplitude, f and g representing the f-th non-zero amplitude and the g-th non-zero amplitude, respectively.
And S403, judging whether the distance between every two adjacent nonzero amplitudes is smaller than a preset distance threshold, and if the distance between every two adjacent nonzero amplitudes is smaller than the preset distance threshold, clustering signal amplitude samples corresponding to the adjacent nonzero amplitudes into a same cluster so as to eliminate random pulse interference signals and obtain a second correction signal.
The method comprises the steps of setting a preset distance threshold according to experience and historical data, clustering signal amplitude samples corresponding to non-zero amplitudes, of which the distance between every two adjacent non-zero amplitudes is smaller than the preset distance threshold, into the same cluster, and eliminating random pulse interference signals in such a way that the distance between the random pulse sample signals is generally longer so as to obtain a second correction signal.
S500, clustering and dividing the signal amplitude samples in the second correction signal into a plurality of clusters based on a cluster clustering method, calculating the length from each cluster to a clustering center, judging whether the length from each cluster to the clustering center is larger than a preset length threshold value, and if so, determining that non-zero partial discharge exists in the power transmission line.
It can be understood that partial discharge is a continuous process, and is reflected in a plurality of signal samples, and the length of a partial discharge signal cluster is generally long, so that it can be determined whether the length from each cluster to a cluster center is greater than a preset length threshold, and if the determination is yes, it is determined that non-zero partial discharge exists in the power transmission line.
S600, fault early warning information is sent to a power grid maintenance center according to the non-zero partial discharge, and the fault early warning information comprises the non-zero partial discharge information and position information of the power transmission line corresponding to the non-zero partial discharge information.
It should be noted that the position information of the power transmission line may determine the coordinate information of the power transmission line through a positioning system of the power grid, so as to help a maintenance worker to quickly determine the position of the power transmission line.
The above is a detailed description of an embodiment of a distribution network line tree drop detection method based on partial discharge provided by the invention, and the following is a detailed description of an embodiment of a distribution network line tree drop detection system based on partial discharge provided by the invention.
For convenience of understanding, please refer to fig. 2, the system for detecting tree falling in a distribution network line based on partial discharge provided by the present invention includes:
the acquisition module 100 is configured to acquire a target signal around the power transmission line according to a preset sampling period, where the target signal in each sampling period includes a plurality of signal amplitude samples, and the target signal includes a partial discharge signal and an interference signal;
in this embodiment, radio frequency antenna receiving equipment is installed at a power transmission line with dense surrounding vegetation, so as to receive a target signal around the power transmission line, where a preset sampling period is 20ms, and the target signal in each sampling period includes 400000 signal amplitude samples.
The target signal may contain a partial discharge signal which is 0 when being acquired, that is, a partial discharge phenomenon is not generated, and the interference signal includes a narrowband interference signal and a random impulse interference signal, wherein a main source of the narrowband interference signal is a wireless signal transmitted by a surrounding radio broadcast transmitter, and the random impulse interference signal is mainly caused by lightning, a switching operation or a discharge. In this embodiment, the radio frequency antenna receiving device can effectively receive the electromagnetic waves generated by the partial discharge and other reasons, and therefore, the radio frequency antenna receiving device can be used to obtain the partial discharge signal and the interference signal around the power transmission line.
A gradient module 200, configured to perform gradient on the target signal to obtain a gradient signal, so as to enhance differentiation between an amplitude of the partial discharge signal and an amplitude of the interference signal;
a first modification module 300, configured to calculate a z-score standard score of each signal amplitude sample in the gradient signal, further configured to determine whether the z-score standard score is greater than a preset z-score standard score threshold, further configured to reject the corresponding signal amplitude sample from the gradient signal when the z-score standard score is greater than the preset z-score standard score threshold, and further configured to retain the corresponding signal amplitude sample when the z-score standard score is not greater than the preset z-score standard score threshold, so as to transform the gradient signal into a first modified signal;
a second correction module 400, configured to analyze the first correction signal based on a cluster clustering method, so as to eliminate a random pulse interference signal in the first correction signal, so as to obtain a second correction signal;
the nonzero judgment module 500 is used for clustering and dividing the signal amplitude samples in the second correction signal into a plurality of clusters based on a cluster clustering method, calculating the length from each cluster to a clustering center, judging whether the length from each cluster to the clustering center is greater than a preset length threshold value, and determining that nonzero partial discharge exists in the power transmission line when the length from each cluster to the clustering center is greater than the preset length threshold value.
It can be understood that partial discharge is a continuous process, and is reflected in a plurality of signal samples, and the length of a partial discharge signal cluster is generally long, so that it can be determined whether the length from each cluster to a cluster center is greater than a preset length threshold, and if the determination is yes, it is determined that non-zero partial discharge exists in the power transmission line.
Further, the gradient module comprises a determination submodule, a gradient calculation submodule and a gradient submodule;
the determining submodule is used for determining the extreme point amplitude of a signal amplitude sample in the target signal;
the gradient operator module is used for calculating the gradient between every two adjacent extreme point amplitudes;
the gradient submodule is used for carrying out gradient on the target signal according to the gradient to obtain a gradient signal, so that the ratio of the amplitude of the partial discharge signal to the amplitude of the interference signal is enhanced.
It should be noted that, in this embodiment, the extreme point amplitude is first found out of 400000 signal amplitude samples, where the extreme point amplitude includes the highest amplitude and the lowest amplitude, and an ascending trend and a descending trend occur in 400000 signal amplitude samples, and the point with the lowest amplitude in the descending trend is the lowest amplitude, and the point with the highest amplitude in the ascending trend is the highest amplitude.
After finding the extreme point amplitude values in the 400000 signal amplitude samples, the gradient between two adjacent extreme points is calculated by the formula,
in which x represents a gradient, wfRepresenting the extreme point, w, corresponding to the f-th signal amplitude samplelIndicating the extreme point corresponding to the ith signal amplitude sample.
After the gradient is obtained through calculation, the target signal is subjected to gradient so as to obtain a gradient signal, and therefore the ratio of the amplitude of the partial discharge signal to the amplitude of the interference signal, namely differentiation, is enhanced.
Further, the second correction module comprises a non-zero amplitude submodule, a distance calculation submodule and a distance judgment submodule;
the non-zero amplitude submodule is used for acquiring a non-zero amplitude in the sample signal amplitude in the first correction signal;
the distance calculation submodule is used for calculating the distance between every two adjacent non-zero amplitudes;
wherein the calculation formula for calculating the distance between every two adjacent non-zero amplitudes is as follows,
in the formula (d)fgRepresenting the distance between the f-th non-zero amplitude and the g-th non-zero amplitude, f and g representing the f-th non-zero amplitude and the g-th non-zero amplitude, respectively.
The distance judgment submodule is used for judging whether the distance between every two adjacent nonzero amplitudes is smaller than a preset distance threshold value or not, and is also used for clustering signal amplitude samples corresponding to the adjacent nonzero amplitudes into a same cluster when the distance between the adjacent nonzero amplitudes is smaller than the preset distance threshold value, so that random pulse interference signals are eliminated, and a second correction signal is obtained.
And setting a preset distance threshold according to experience and historical data, clustering signal amplitude samples corresponding to non-zero amplitudes of which the distance between every two adjacent non-zero amplitudes is smaller than the preset distance threshold into the same cluster, wherein the distance between the random pulse sample signals is generally longer, and eliminating random pulse interference signals by the mode so as to obtain a second correction signal.
Further, the system also includes: the device comprises a positioning module and a sending module;
the positioning module is used for acquiring position information of the power transmission line corresponding to the non-zero partial discharge;
and the sending module is used for sending fault early warning information to the power grid maintenance center according to the non-zero partial discharge, wherein the fault early warning information comprises the non-zero partial discharge information and the position information of the power transmission line corresponding to the non-zero partial discharge information.
In this embodiment, by acquiring a target signal including a partial discharge signal and an interference signal around a transmission line surrounded by trees, the target signal is graded to enhance the difference between the amplitude of the partial discharge signal and the amplitude of the interference signal, so as to filter the interference signals subsequently, and then eliminate the interference signals in the target signals by using the z-score standard score and clustering method, dividing a signal amplitude sample in a second correction signal with interference signals removed into a plurality of clusters by using a cluster clustering method, determining whether non-zero partial discharge exists in the clusters or not according to the length from each cluster to a clustering center, namely determining that the non-zero partial discharge exists in the power transmission line, wherein the non-zero partial discharge indicates that trees fall to the power transmission line to generate the non-zero partial discharge, therefore, the technical problem that the high-impedance fault caused by the falling of the trees in the distribution network line is difficult to detect is solved.
In the several embodiments provided in the present application, it should be understood that the disclosed apparatus and method may be implemented in other ways. For example, the above-described apparatus embodiments are merely illustrative, and for example, a division of a unit is merely a logical division, and an actual implementation may have another division, for example, a plurality of units or components may be combined or integrated into another system, or some features may be omitted, or not executed. In addition, the shown or discussed mutual coupling or direct coupling or communication connection may be an indirect coupling or communication connection through some interfaces, devices or units, and may be in an electrical, mechanical or other form.
The units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of the embodiment.
In addition, functional units in the embodiments of the present application may be integrated into one processing unit, or each unit may exist alone physically, or two or more units are integrated into one unit. The integrated unit can be realized in a form of hardware, and can also be realized in a form of a software functional unit.
The above embodiments are only used for illustrating the technical solutions of the present application, and not for limiting the same; although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions in the embodiments of the present application.
Claims (9)
1. A distribution network line tree falling detection method based on partial discharge is applied to a power transmission line surrounded by trees and is characterized by comprising the following steps:
s1, obtaining target signals around the power transmission line according to a preset sampling period, wherein the target signals in each sampling period comprise a plurality of signal amplitude samples, and the target signals comprise partial discharge signals and interference signals;
s2, carrying out gradient on the target signal to obtain a gradient signal, so as to enhance the difference between the amplitude of the partial discharge signal and the amplitude of the interference signal;
s3, calculating a z-score standard score of each signal amplitude sample in the gradient signal, judging whether the z-score standard score is larger than a preset z-score standard score threshold value, if so, rejecting the corresponding signal amplitude sample in the gradient signal, and if not, retaining the corresponding signal amplitude sample so as to transform the gradient signal into a first correction signal;
s4, analyzing the first correction signal based on a cluster clustering method, so as to eliminate random pulse interference signals in the first correction signal, and obtain a second correction signal;
s5, clustering and dividing the signal amplitude samples in the second correction signal into a plurality of clusters based on a cluster clustering method, calculating the length from each cluster to a clustering center, judging whether the length from each cluster to the clustering center is larger than a preset length threshold value, and if so, determining that the non-zero partial discharge exists in the power transmission line.
2. The method for detecting tree falling in distribution network lines based on partial discharge of claim 1, wherein the step S1 specifically comprises:
the method comprises the steps that target signals around the power transmission line are obtained according to preset sampling periods based on radio frequency antenna receiving equipment, the target signals in each sampling period comprise a plurality of signal amplitude samples, the target signals comprise partial discharge signals and interference signals, and the interference signals comprise narrow-band interference signals and random pulse interference signals.
3. The method for detecting tree falling in distribution network lines based on partial discharge of claim 1, wherein the step S2 specifically comprises:
determining the extreme point amplitude of a signal amplitude sample in the target signal, calculating the gradient between every two adjacent extreme point amplitudes, and carrying out gradient processing on the target signal according to the gradient to obtain a gradient signal, so that the ratio of the amplitude of the partial discharge signal to the amplitude of the interference signal is enhanced.
4. The method for detecting tree falling in distribution network lines based on partial discharge of claim 1, wherein the step S4 specifically comprises:
s401, obtaining a non-zero amplitude value in the sample signal amplitude values in the first correction signal;
s402, calculating the distance between every two adjacent non-zero amplitudes;
and S403, judging whether the distance between every two adjacent nonzero amplitudes is smaller than a preset distance threshold, and if the distance between every two adjacent nonzero amplitudes is smaller than the preset distance threshold, clustering signal amplitude samples corresponding to the adjacent nonzero amplitudes into a same cluster so as to eliminate random pulse interference signals and obtain a second correction signal.
5. The method for detecting tree falling in distribution network lines based on partial discharge of claim 1, wherein step S5 is followed by:
and S6, sending fault early warning information to a power grid maintenance center according to the non-zero partial discharge, wherein the fault early warning information comprises the non-zero partial discharge information and the position information of the power transmission line corresponding to the non-zero partial discharge information.
6. The utility model provides a join in marriage net twine way trees detection system that falls based on partial discharge which characterized in that includes:
the acquisition module is used for acquiring target signals around the power transmission line according to preset sampling periods, wherein the target signals in each sampling period comprise a plurality of signal amplitude samples, and the target signals comprise partial discharge signals and interference signals;
the gradient module is used for carrying out gradient on the target signal to obtain a gradient signal so as to enhance the difference between the amplitude of the partial discharge signal and the amplitude of the interference signal;
a first modification module, configured to calculate a z-score standard score of each signal amplitude sample in the gradient signal, further configured to determine whether the z-score standard score is greater than a preset z-score standard score threshold, further configured to, when the z-score standard score is greater than the preset z-score standard score threshold, eliminate the corresponding signal amplitude sample from the gradient signal, and further configured to, when the z-score standard score is not greater than the preset z-score standard score threshold, retain the corresponding signal amplitude sample, thereby transforming the gradient signal into a first modified signal;
the second correction module is used for analyzing the first correction signal based on a cluster clustering method so as to eliminate random pulse interference signals in the first correction signal to obtain a second correction signal;
and the non-zero judgment module is used for clustering and dividing the signal amplitude samples in the second correction signal into a plurality of clusters based on a cluster clustering method, calculating the length from each cluster to a clustering center, judging whether the length from each cluster to the clustering center is greater than a preset length threshold value, and determining that the non-zero partial discharge exists in the power transmission line when the length from each cluster to the clustering center is greater than the preset length threshold value.
7. The partial discharge-based distribution network line tree fall detection system of claim 6, wherein the gradient module comprises a determination sub-module, a gradient calculation sub-module, and a gradient sub-module;
the determining submodule is used for determining the extreme point amplitude of a signal amplitude sample in the target signal;
the gradiometer module is used for calculating the gradient between the amplitudes of every two adjacent extreme points;
the gradient submodule is used for carrying out gradient on the target signal according to the gradient to obtain a gradient signal, so that the ratio of the amplitude of the partial discharge signal to the amplitude of the interference signal is enhanced.
8. The system for detecting tree falling in a distribution network line based on partial discharge of claim 6, wherein the second correction module comprises a non-zero amplitude sub-module, a distance calculation sub-module and a distance judgment sub-module;
the non-zero amplitude submodule is used for acquiring a non-zero amplitude in the sample signal amplitudes in the first correction signal;
the distance calculation submodule is used for calculating the distance between every two adjacent non-zero amplitudes;
the distance judgment submodule is used for judging whether the distance between every two adjacent nonzero amplitudes is smaller than a preset distance threshold value or not, and is also used for clustering signal amplitude samples corresponding to the adjacent nonzero amplitudes into a same cluster when the distance between the adjacent nonzero amplitudes is smaller than the preset distance threshold value, so that random pulse interference signals are eliminated, and a second correction signal is obtained.
9. The partial discharge-based tree fall detection system for distribution network lines of claim 6, further comprising: the device comprises a positioning module and a sending module;
the positioning module is used for acquiring the position information of the power transmission line corresponding to the non-zero partial discharge;
and the sending module is used for sending fault early warning information to a power grid maintenance center according to the non-zero partial discharge, wherein the fault early warning information comprises the non-zero partial discharge information and the position information of the power transmission line corresponding to the non-zero partial discharge information.
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