CN113933750B - Method, device, equipment and storage medium for detecting high-resistance ground fault of power distribution network - Google Patents
Method, device, equipment and storage medium for detecting high-resistance ground fault of power distribution network Download PDFInfo
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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 application discloses a detection method, a device, equipment and a storage medium for high-resistance ground faults of a power distribution network, wherein the method comprises the following steps: acquiring an anchor point modal function corresponding to a power distribution network to be detected; carrying out multi-layer decomposition on the current signal of the power distribution network to be detected to obtain a full filter coefficient corresponding to the current signal; calculating a fraction filter coefficient corresponding to the current signal according to the full filter coefficient and the anchor point modal function; calculating the energy of the fractional filter coefficient corresponding to the fractional filter coefficient by presetting an energy calculation formula; and obtaining a high-resistance ground fault detection result of the power distribution network to be detected according to a comparison result of the fractional filter coefficient energy and a preset energy threshold value. The method solves the technical problem of low detection speed of the existing detection method for the high-resistance ground fault of the power distribution network.
Description
Technical Field
The application relates to the technical field of power distribution networks, in particular to a method, a device, equipment and a storage medium for detecting high-resistance ground faults of a power distribution network.
Background
The quality requirements of the modern society on electric energy are higher and higher, and the stability of the electric energy can be effectively ensured by fault detection on the power distribution network. In the power distribution network faults, high-resistance ground faults are important problems in the power distribution network faults, so that the method has important significance in rapid and accurate detection.
The high-resistance ground faults of the distribution network have different voltage-current characteristics due to different fault medium material types, air humidity, weather environments, contact areas and the like. The existing detection of the high-resistance ground faults of the power distribution network mainly depends on a neural network, a support vector machine and other machine learning methods, however, the classifier used in the detection method is complex, so that the calculated amount is large, and the detection speed is further low.
Disclosure of Invention
In view of the above, the application provides a method, a device, equipment and a storage medium for detecting a high-resistance ground fault of a power distribution network, which solve the technical problem of slower detection speed of the existing method for detecting the high-resistance ground fault of the power distribution network.
The first aspect of the present application provides a method for detecting a high-resistance ground fault of a power distribution network, including:
acquiring an anchor point modal function corresponding to a power distribution network to be detected;
carrying out multi-layer decomposition on the current signal of the power distribution network to be detected to obtain a full filter coefficient corresponding to the current signal;
calculating a fraction filter coefficient corresponding to the current signal according to the full filter coefficient and the anchor point modal function;
calculating the energy of the fractional filter coefficient corresponding to the fractional filter coefficient by presetting an energy calculation formula;
and obtaining a high-resistance ground fault detection result of the power distribution network to be detected according to a comparison result of the fractional filter coefficient energy and a preset energy threshold value.
Optionally, acquiring an anchor point modal function corresponding to the power distribution network to be detected specifically includes:
searching all maximum value points and all minimum value points of the historical current in the power distribution network to be detected;
determining anchor points corresponding to the power distribution network to be detected according to all the maximum value points and the minimum value points;
interpolation processing is carried out on all the anchor points based on an extrapolation method, so that corresponding anchor point curves are obtained;
and performing difference on the historical current and the anchor point curve to obtain an anchor point modal function corresponding to the power distribution network to be detected.
Optionally, determining, according to all the maximum value points and the minimum value points, an anchor point corresponding to the power distribution network to be detected specifically includes:
interpolation processing is carried out on all the maximum value points through a kriging interpolation method, and an upper boundary line is obtained;
performing interpolation processing on all the minimum value points by an external interpolation method to obtain a lower boundary;
determining an anchor point corresponding to the power distribution network to be detected based on an anchor point calculation formula, the maximum value point, the minimum value point, the upper boundary and the lower boundary, wherein the anchor point calculation formula is as follows:
in the formula an t As anchor point, up t As maximum point, lo t Is the minimum point, f 2 (lo t ) For the lower boundary line, f 1 (up t ) For the upper boundary, t is the number of collected data points, t=1, 2.
Optionally, performing multi-layer decomposition on the current signal of the power distribution network to be detected to obtain a full filter coefficient corresponding to the current signal, which specifically includes:
acquiring a current signal and a basic filter of the power distribution network to be detected;
multiplying the current signal by the basic filter to obtain a basic full-filter coefficient corresponding to the basic filter;
and updating the basic filter for a plurality of times, and calculating a new full filter coefficient corresponding to the new basic filter after each updating.
Optionally, the base filter includes a base scaling filter and a base coefficient filter.
Optionally, multiplying the current signal with the basic filter to obtain a basic full filter coefficient corresponding to the basic filter, including:
multiplying the current signal by the basic proportional filter to obtain a first basic full-filter coefficient corresponding to the basic proportional filter;
and multiplying the current signal by the basic coefficient filter to obtain a second basic full-filter coefficient corresponding to the basic coefficient filter.
Optionally, the method further comprises:
when the high-resistance ground fault detection result is a high-resistance ground fault, calculating the ground resistance corresponding to the power distribution network to be detected;
when the grounding resistance is a value above a preset resistance value, outputting a high-resistance grounding fault signal;
and when the grounding resistance is smaller than the preset resistance value, adjusting the preset energy threshold value, and re-determining the high-resistance grounding fault detection result of the power distribution network to be detected after the adjusted preset energy threshold value.
The second aspect of the present application provides a detection apparatus for high-resistance ground fault of power distribution network, including:
the acquisition unit is used for acquiring an anchor point modal function corresponding to the power distribution network to be detected;
the decomposition unit is used for carrying out multi-layer decomposition on the current signal of the power distribution network to be detected to obtain a full-filter coefficient corresponding to the current signal;
the first calculation unit is used for calculating a fraction filter coefficient corresponding to the current signal according to the full filter coefficient and the anchor point modal function;
the second calculation unit is used for calculating the fractional filter coefficient energy corresponding to the fractional filter coefficient through a preset energy calculation formula;
and the judging unit is used for obtaining the high-resistance ground fault detection result of the power distribution network to be detected according to the comparison result of the fractional filter coefficient energy and the preset energy threshold value.
The third aspect of the application provides a detection device for high-resistance ground faults of a power distribution network, which comprises a processor and a memory;
the memory is used for storing program codes and transmitting the program codes to the processor;
the processor is configured to execute the method for detecting a high-resistance ground fault of the power distribution network according to any one of the first aspects according to instructions in the program code.
A fourth aspect of the present application provides a storage medium, where the storage medium is configured to store program code, where the program code is configured to perform any one of the methods for detecting a high-resistance ground fault of a power distribution network according to the first aspect.
From the above technical scheme, the application has the following advantages:
the application provides a detection method of a high-resistance ground fault of a power distribution network, which comprises the steps of firstly obtaining an anchor point modal function corresponding to a power distribution network to be detected, then carrying out multi-layer decomposition on a current signal of the power distribution network to be detected to obtain a full filter coefficient corresponding to the current signal, then calculating a fractional filter coefficient corresponding to the current signal according to the full filter coefficient and the anchor point modal function, then calculating fractional filter coefficient energy corresponding to the fractional filter coefficient through a preset energy calculation formula, and finally obtaining a high-resistance ground fault detection result of the power distribution network to be detected according to a comparison result of the fractional filter coefficient energy and a preset energy threshold value.
According to the method, the energy of the fractional filter coefficient serving as the characteristic criterion of the high-resistance ground fault is calculated according to the full filter coefficient and the anchor point empirical mode method, the high-resistance ground fault detection result of the power distribution network to be detected is obtained based on the energy of the fractional filter coefficient, and the classifier is not used in the whole detection process, so that the technical problem that the detection speed is low due to the fact that the classifier is used in the existing detection method for the high-resistance ground fault of the power distribution network is solved.
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In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are needed in the description of the embodiments will be briefly described below, it being obvious that the drawings in the following description are only some embodiments of the present application, and that other drawings may be obtained according to these drawings without inventive effort to a person skilled in the art.
Fig. 1 is a schematic flow chart of a first embodiment of a method for detecting a high-resistance ground fault of a power distribution network according to an embodiment of the present application;
fig. 2 is a schematic flow chart of a second embodiment of a method for detecting a high-resistance ground fault of a power distribution network according to an embodiment of the present application;
fig. 3 is a schematic structural diagram of a device for detecting a high-resistance ground fault of a power distribution network in an embodiment of the application.
Detailed Description
The embodiment of the application provides a detection method, a device, equipment and a storage medium for high-resistance ground faults of a power distribution network, which solve the technical problem of low detection speed caused by using a classifier in the existing detection method for the high-resistance ground faults of the power distribution network.
In order to make the present application solution better understood by those skilled in the art, the following description will clearly and completely describe the technical solution in the embodiments of the present application with reference to the accompanying drawings in the embodiments of the present application, and it is apparent that the described embodiments are only some embodiments of the present application, not all embodiments. All other embodiments, which can be made by one of ordinary skill in the art without undue burden from the present disclosure, are within the scope of the present disclosure.
An embodiment of a method for detecting a high-resistance ground fault of a power distribution network is provided in a first aspect of the present application.
Referring to fig. 1, a flow chart of a first embodiment of a method for detecting a high-resistance ground fault of a power distribution network according to an embodiment of the present application is shown.
The method for detecting the high-resistance ground fault of the power distribution network in the embodiment comprises the following steps:
step 101, acquiring an anchor point modal function corresponding to the power distribution network to be detected.
And 102, carrying out multi-layer decomposition on the current signal of the power distribution network to be detected to obtain a full filter coefficient corresponding to the current signal.
And 103, calculating a fractional filter coefficient corresponding to the current signal according to the full filter coefficient and the anchor point modal function.
It will be appreciated that after the full filter coefficient and the anchor point mode function are obtained, the fractional filter coefficient corresponding to the current signal may be calculated according to the full filter coefficient and the anchor point mode function.
Specifically, in one embodiment, the calculation formula of the fractional filter coefficient is:
in the formula, nd q For the q-th fractional filter coefficient, I J,q Is the q-th full filter coefficient, f 4 () As anchor point mode function, f 4 (I J,q ) And the anchor point modal function corresponding to the q-th full filter coefficient.
Step 104, calculating the fractional filter coefficient energy corresponding to the fractional filter coefficient through a preset energy calculation formula.
Specifically, in one embodiment, the preset energy calculation formula may be:
where End is the fractional filter coefficient energy.
And 105, obtaining a high-resistance ground fault detection result of the power distribution network to be detected according to a comparison result of the fractional filter coefficient energy and a preset energy threshold value.
Finally, after the fractional filter coefficient energy is obtained, the high-resistance ground fault detection result of the power distribution network to be detected can be obtained by comparing the fractional filter coefficient energy with a preset energy threshold.
It will be appreciated that the magnitude of the preset energy threshold may be selected according to actual needs, which is not specifically limited in this embodiment.
In this embodiment, an anchor point modal function corresponding to a power distribution network to be detected is first obtained, then a current signal of the power distribution network to be detected is subjected to multi-layer decomposition to obtain a full filter coefficient corresponding to the current signal, then a fractional filter coefficient corresponding to the current signal is calculated according to the full filter coefficient and the anchor point modal function, then fractional filter coefficient energy corresponding to the fractional filter coefficient is calculated through a preset energy calculation formula, and finally a high-resistance ground fault detection result of the power distribution network to be detected is obtained according to a comparison result of the fractional filter coefficient energy and a preset energy threshold value. In the embodiment, the fractional filter coefficient energy serving as the high-resistance ground fault characteristic criterion is calculated according to the full filter coefficient and the anchor point empirical mode method, the high-resistance ground fault detection result of the power distribution network to be detected is obtained based on the fractional filter coefficient energy, and a classifier is not used in the whole detection process, so that the technical problem that the detection speed is low due to the fact that the classifier is used in the existing detection method for the high-resistance ground fault of the power distribution network is solved.
The foregoing is a first embodiment of a method for detecting a high-resistance ground fault of a power distribution network provided by an embodiment of the present application, and the following is a second embodiment of a method for detecting a high-resistance ground fault of a power distribution network provided by an embodiment of the present application.
Referring to fig. 2, a flow chart of a second embodiment of a method for detecting a high-resistance ground fault of a power distribution network according to an embodiment of the present application is shown.
The method for detecting the high-resistance ground fault of the power distribution network in the embodiment comprises the following steps:
step 201, retrieving all maximum value points and all minimum value points of historical current in a power distribution network to be detected.
Step 202, determining anchor points corresponding to the power distribution network to be detected according to all the maximum value points and the minimum value points.
It can be understood that determining the anchor point corresponding to the power distribution network to be detected according to all the maximum value points and the minimum value points specifically includes:
interpolation processing is carried out on all maximum points through a kriging interpolation method, and an upper boundary line is obtained;
interpolation processing is carried out on all minimum value points through an external interpolation method, and a lower boundary line is obtained;
determining an anchor point corresponding to the power distribution network to be detected based on an anchor point calculation formula, a maximum point, a minimum point, an upper boundary and a lower boundary, wherein the anchor point calculation formula is as follows:
in the formula an t As anchor point, up t As maximum point, lo t Is the minimum point, f 2 (lo t ) For the lower boundary line, f 1 (up t ) For the upper boundary, t is the number of collected data points, t=1, 2. f (f) 1 () For interpolation function corresponding to kriging interpolation method, f 2 () Interpolation function when interpolation processing is carried out to the minimum value for extrapolation method.
As can be seen from the above steps, the upper boundary f 2 (up t ) And lower partBoundary line f 1 (lo t ) The method comprises the following steps of:
y up ＝f 1 (up t ),t＝1,2,...n；
y lo ＝f 2 (lo t ),t＝1,2,...n。
and 203, carrying out interpolation processing on all anchor points based on an extrapolation method to obtain corresponding anchor point curves.
Namely: the anchor point curve obtained is:
y an ＝f 3 (an t ),t＝1,2,...n。
wherein y is an For the anchor curve, f 3 () And (5) performing interpolation processing on the anchor points for an extrapolation method.
And 204, performing difference on the historical current and the anchor point curve to obtain an anchor point modal function corresponding to the power distribution network to be detected.
The obtained anchor point modal function f 4 (t) is:
f 4 (t)＝y t -f 3 (an t )；
wherein y is t Is the historical current.
Step 205, obtaining a current signal and a basic filter of the power distribution network to be detected.
It will be appreciated that in one embodiment, the base filter includes a base scale filter and a base coefficient filter. Correspondingly, the basic proportion filter r j,m M=1, 2, M and base coefficient filter c j,m M=1, 2..m, M represents the filter length.
Construction of a proportional filterCoefficient filter->Where f is the fundamental frequency.
And 206, multiplying the current signal by the basic filter to obtain a basic full-filter coefficient corresponding to the basic filter.
In one embodiment, multiplying the current signal by the base filter to obtain a base full filter coefficient corresponding to the base filter includes:
multiplying the current signal by a basic proportional filter to obtain a first basic full-filter coefficient corresponding to the basic proportional filter;
and multiplying the current signal by the basic coefficient filter to obtain a second basic full-filter coefficient corresponding to the basic coefficient filter.
I.e. the first basic full filter coefficient I j+1，j And a second basic full filter coefficient I j+1，j+1 The method comprises the following steps:
it can be understood that the obtained basic full filter coefficients are all the full filter coefficients I of the j th level j+1，j ，I j+1，j+1 。
And step 207, updating the basic filter for a plurality of times, and calculating a new full filter coefficient corresponding to the new basic filter after each updating.
It will be appreciated that, particularly at update time, 0 is inserted between each element in the base proportional filter, and 1 is inserted between each element in the base coefficient filter, i.e
r j+1，m ＝{r j，1 ，0，r j，2 ，0...r j，2M-13 ，0，r j，2M-1 }；
c j+1，m ＝{c j，1 ，1，c j，2 ，1...c j，2M-3 ，1，c j，2M-1 }。
Repeating the operation for J times, wherein J is a preset filtering level, and obtaining 2 J All filter coefficients are respectively
And step 208, calculating a fractional filter coefficient corresponding to the current signal according to the full filter coefficient and the anchor point modal function.
It is to be understood that the description of step 208 is the same as that of step 103 in the first embodiment, and specific reference may be made to the description of step 103, which is not repeated herein.
Step 209, calculating the fractional filter coefficient energy corresponding to the fractional filter coefficient through a preset energy calculation formula.
It is to be understood that the description of step 209 and step 104 in the first embodiment is the same, and specific reference may be made to the description of step 104, which is not repeated herein.
Step 210, obtaining a high-resistance ground fault detection result of the power distribution network to be detected according to a comparison result of the fractional filter coefficient energy and a preset energy threshold value.
It will be appreciated that when the fractional filter coefficient energy End is greater than the preset energy threshold epsilon, then a high resistance ground fault is deemed to be detected, otherwise no high resistance ground fault is deemed to have occurred.
Step 211, when the high-resistance ground fault detection result is a high-resistance ground fault, calculating the ground resistance corresponding to the power distribution network to be detected.
In this embodiment, after the high-resistance ground fault is detected, the ground resistance is calculated, and the secondary verification is performed, and the high-resistance ground fault determination coefficient (preset energy threshold) is corrected according to the determination threshold by the ground resistance, so that the accuracy of high-resistance ground fault detection can be gradually improved, and the method is suitable for different fault environments.
It will be appreciated that the specific calculation steps for the ground resistance include:
step 1, collecting neutral point voltage before and after faultThree-phase earth current sum before and after faultThe feeder line is three-phase to earth susceptance B.
Step 2, calculating the neutral point voltage change value delta U 0 And three-phase earth current and change value delta I s ；
Step 3, calculating a formula and a neutral point voltage change value delta U through the ground resistance 0 And three-phase earth current and change value delta I s Calculating a grounding resistance, wherein the grounding resistance R f The calculation formula of (2) is as follows:
in U f And B is the feeder three-phase relative earth susceptance.
And 212, outputting a high-resistance ground fault signal when the ground resistance is above a preset resistance value.
And 213, when the grounding resistance is smaller than the preset resistance value, adjusting a preset energy threshold value, and re-determining a high-resistance grounding fault detection result of the power distribution network to be detected according to the adjusted preset energy threshold value.
It will be appreciated that for a preset energy threshold epsilon adjustment, the following may be used: modifying ε to ε×sin pi|R f And delta is a preset resistance value.
Compared with the prior art, the embodiment has the following advantages:
(1) The method is mainly based on the fractional filter coefficient energy as a criterion, the signal acquisition amount and the analyzed total amount are small, the three steps can be synchronously carried out, and the detection efficiency is high.
(2) The ground fault resistance is calculated, the high-resistance ground fault judgment coefficient is corrected according to the judgment threshold value, the accuracy of high-resistance ground fault detection can be gradually improved, and the method is suitable for different fault environments.
(3) And the whole filter coefficient is obtained, and an anchor point empirical mode method is adopted to remove integer harmonic components, so that the influence of common interference sources is avoided.
In this embodiment, an anchor point modal function corresponding to a power distribution network to be detected is first obtained, then a current signal of the power distribution network to be detected is subjected to multi-layer decomposition to obtain a full filter coefficient corresponding to the current signal, then a fractional filter coefficient corresponding to the current signal is calculated according to the full filter coefficient and the anchor point modal function, then fractional filter coefficient energy corresponding to the fractional filter coefficient is calculated through a preset energy calculation formula, and finally a high-resistance ground fault detection result of the power distribution network to be detected is obtained according to a comparison result of the fractional filter coefficient energy and a preset energy threshold value. In the embodiment, the fractional filter coefficient energy serving as the high-resistance ground fault characteristic criterion is calculated according to the full filter coefficient and the anchor point empirical mode method, the high-resistance ground fault detection result of the power distribution network to be detected is obtained based on the fractional filter coefficient energy, and a classifier is not used in the whole detection process, so that the technical problem that the detection speed is low due to the fact that the classifier is used in the existing detection method for the high-resistance ground fault of the power distribution network is solved.
The second aspect of the embodiment of the application provides an embodiment of a detection device for a high-resistance ground fault of a power distribution network.
Referring to fig. 3, a schematic structural diagram of a device for detecting a high-resistance ground fault of a power distribution network in an embodiment of the present application is shown.
The device for detecting a high-resistance ground fault of a power distribution network in this embodiment includes:
the acquisition unit is used for acquiring an anchor point modal function corresponding to the power distribution network to be detected;
the decomposition unit is used for carrying out multi-layer decomposition on the current signal of the power distribution network to be detected to obtain a full-filter coefficient corresponding to the current signal;
the first calculation unit is used for calculating a fraction filter coefficient corresponding to the current signal according to the full filter coefficient and the anchor point modal function;
the second calculation unit is used for calculating the fractional filter coefficient energy corresponding to the fractional filter coefficient through a preset energy calculation formula;
and the judging unit is used for obtaining a high-resistance ground fault detection result of the power distribution network to be detected according to the comparison result of the fractional filter coefficient energy and the preset energy threshold value.
Further, the acquisition unit specifically includes:
the searching subunit is used for searching all maximum value points and all minimum value points of the historical current in the power distribution network to be detected;
the determining subunit is used for determining anchor points corresponding to the power distribution network to be detected according to all the maximum value points and the minimum value points;
the interpolation subunit is used for carrying out interpolation processing on all the anchor points based on an extrapolation method to obtain corresponding anchor point curves;
and the difference making subunit is used for making difference between the historical current and the anchor point curve to obtain an anchor point modal function corresponding to the power distribution network to be detected.
Further, the determining subunit is specifically configured to:
interpolation processing is carried out on all maximum points through a kriging interpolation method, and an upper boundary line is obtained;
interpolation processing is carried out on all minimum value points through an external interpolation method, and a lower boundary line is obtained;
determining an anchor point corresponding to the power distribution network to be detected based on an anchor point calculation formula, a maximum point, a minimum point, an upper boundary and a lower boundary, wherein the anchor point calculation formula is as follows:
in the formula an t As anchor point, up t As maximum point, lo t Is the minimum point, f 2 (lo t ) For the lower boundary line, f 1 (up t ) For the upper boundary, t is the number of collected data points, t=1, 2.
Specifically, the decomposition unit specifically includes:
the acquisition subunit is used for acquiring a current signal and a basic filter of the power distribution network to be detected;
the multiplying subunit is used for multiplying the current signal and the basic filter to obtain a basic full-filter coefficient corresponding to the basic filter;
and the updating subunit is used for updating the basic filter for a plurality of times and calculating a new full filter coefficient corresponding to the new basic filter after each updating.
Specifically, the base filter includes a base scale filter and a base coefficient filter.
Optionally, the multiplying subunit is specifically configured to:
multiplying the current signal by a basic proportional filter to obtain a first basic full-filter coefficient corresponding to the basic proportional filter;
and multiplying the current signal by the basic coefficient filter to obtain a second basic full-filter coefficient corresponding to the basic coefficient filter.
Further, the power distribution network high-resistance ground fault detection device in this embodiment further includes:
the third calculation unit is used for calculating the grounding resistance corresponding to the power distribution network to be detected when the high-resistance grounding fault detection result is a high-resistance grounding fault;
the output unit is used for outputting a high-resistance ground fault signal when the ground resistance is a value above a preset resistance value;
and the adjusting unit is used for adjusting the preset energy threshold value when the grounding resistance is smaller than the preset resistance value, and redetermining the high-resistance grounding fault detection result of the power distribution network to be detected after the adjusted preset energy threshold value.
In this embodiment, an anchor point modal function corresponding to a power distribution network to be detected is first obtained, then a current signal of the power distribution network to be detected is subjected to multi-layer decomposition to obtain a full filter coefficient corresponding to the current signal, then a fractional filter coefficient corresponding to the current signal is calculated according to the full filter coefficient and the anchor point modal function, then fractional filter coefficient energy corresponding to the fractional filter coefficient is calculated through a preset energy calculation formula, and finally a high-resistance ground fault detection result of the power distribution network to be detected is obtained according to a comparison result of the fractional filter coefficient energy and a preset energy threshold value. In the embodiment, the fractional filter coefficient energy serving as the high-resistance ground fault characteristic criterion is calculated according to the full filter coefficient and the anchor point empirical mode method, the high-resistance ground fault detection result of the power distribution network to be detected is obtained based on the fractional filter coefficient energy, and a classifier is not used in the whole detection process, so that the technical problem that the detection speed is low due to the fact that the classifier is used in the existing detection method for the high-resistance ground fault of the power distribution network is solved.
A third aspect of the embodiments of the present application provides an embodiment of a detection device for a high-resistance ground fault of a power distribution network.
A detection device for high-resistance ground faults of a power distribution network comprises a processor and a memory; the memory is used for storing the program codes and transmitting the program codes to the processor; the processor is configured to perform the method for detecting a high-resistance ground fault of the power distribution network of the first aspect according to instructions in the program code.
A fourth aspect of the present embodiments provides an embodiment of a storage medium.
A storage medium for storing program code for performing the method of detecting a high-resistance ground fault of a power distribution network of the first aspect.
It will be clear to those skilled in the art that, for convenience and brevity of description, specific working procedures of the apparatus and units described above may refer to corresponding procedures in the foregoing method embodiments, which are not described herein again.
In the several embodiments provided in this 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, e.g., the division of units is merely a logical function division, and there may be additional divisions in actual implementation, e.g., multiple units or components may be combined or integrated into another grid network to be installed, or some features may be omitted or not performed. Alternatively, the coupling or direct coupling or communication connection shown or discussed with each other may be an indirect coupling or communication connection via some interfaces, devices or units, which may be in electrical, mechanical or other form.
The units described as separate units may or may not be physically separate, and units shown as units may or may not be physical units, may be located in one place, or may be distributed over a plurality of network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.
In addition, each functional unit in each embodiment of the present application may be integrated in one processing unit, or each unit may exist alone physically, or two or more units may be integrated in one unit. The integrated units may be implemented in hardware or in software functional units.
The integrated units, if implemented in the form of software functional units and sold or used as stand-alone products, may be stored in a computer readable storage medium. Based on such understanding, the technical solution of the present application may be embodied in essence or a part contributing to the prior art or all or part of the technical solution in the form of a software product stored in a storage medium, including several instructions to cause a computer device (which may be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the methods described in the embodiments of the present application. And the aforementioned storage medium includes: a usb disk, a removable hard disk, a Read-only memory (ROM), a random access memory (RAM, randomAccessMemory), a magnetic disk, or an optical disk, or other various media capable of storing program codes.
The above embodiments are merely for illustrating the technical solution 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 scheme described in the foregoing embodiments can be modified or some technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit and scope of the corresponding technical solutions.
Claims (8)
1. The utility model provides a detection method of high-resistance ground fault of power distribution network, which is characterized by comprising the following steps:
acquiring an anchor point modal function corresponding to a power distribution network to be detected;
the obtaining the anchor point modal function corresponding to the power distribution network to be detected specifically comprises the following steps:
searching all maximum value points and all minimum value points of the historical current in the power distribution network to be detected;
determining anchor points corresponding to the power distribution network to be detected according to all the maximum value points and the minimum value points;
interpolation processing is carried out on all the anchor points based on an extrapolation method, so that corresponding anchor point curves are obtained;
performing difference on the historical current and the anchor point curve to obtain an anchor point modal function corresponding to the power distribution network to be detected;
the detection method further comprises the following steps:
carrying out multi-layer decomposition on the current signal of the power distribution network to be detected to obtain a full filter coefficient corresponding to the current signal;
performing multi-layer decomposition on the current signal of the power distribution network to be detected to obtain a full filter coefficient corresponding to the current signal, wherein the full filter coefficient comprises the following specific steps:
acquiring a current signal and a basic filter of the power distribution network to be detected;
multiplying the current signal by the basic filter to obtain a basic full-filter coefficient corresponding to the basic filter;
updating the basic filter for a preset number of times, calculating a new full filter coefficient corresponding to the new basic filter after each update, and taking the obtained basic full filter coefficient as the full filter coefficient corresponding to the current signal;
the detection method further comprises the following steps:
calculating a fraction filter coefficient corresponding to the current signal according to the full filter coefficient and the anchor point modal function;
the calculation formula of the fractional filter coefficient is as follows:
in the formula, nd q For the q-th fractional filter coefficient, I J,q Is the q-th full filter coefficient, f 4 () As anchor point mode function, f 4 (I J,q ) An anchor point modal function corresponding to the q-th full filter coefficient;
calculating the energy of the fractional filter coefficient corresponding to the fractional filter coefficient by presetting an energy calculation formula;
and obtaining a high-resistance ground fault detection result of the power distribution network to be detected according to a comparison result of the fractional filter coefficient energy and a preset energy threshold value.
2. The method for detecting a high-resistance ground fault of a power distribution network according to claim 1, wherein determining the anchor point corresponding to the power distribution network to be detected according to all the maximum value points and the minimum value points specifically comprises:
interpolation processing is carried out on all the maximum value points through a kriging interpolation method, and an upper boundary line is obtained;
performing interpolation processing on all the minimum value points by an external interpolation method to obtain a lower boundary;
determining an anchor point corresponding to the power distribution network to be detected based on an anchor point calculation formula, the maximum value point, the minimum value point, the upper boundary and the lower boundary, wherein the anchor point calculation formula is as follows:
in the formula an t As anchor point, up t As maximum point, lo t Is the minimum point, f 2 (lo t ) For the lower boundary line, f 1 (up t ) For the upper boundary, t is the number of collected data points, t=1, 2.
3. The method for detecting a high-resistance ground fault of a power distribution network according to claim 1, wherein the basic filter comprises a basic proportional filter and a basic coefficient filter.
4. A method for detecting a high-resistance ground fault of a power distribution network according to claim 3, wherein multiplying the current signal by the basic filter to obtain a basic full filter coefficient corresponding to the basic filter comprises:
multiplying the current signal by the basic proportional filter to obtain a first basic full-filter coefficient corresponding to the basic proportional filter;
and multiplying the current signal by the basic coefficient filter to obtain a second basic full-filter coefficient corresponding to the basic coefficient filter.
5. The method for detecting a high-resistance ground fault in a power distribution network according to claim 1, further comprising:
when the high-resistance ground fault detection result is a high-resistance ground fault, calculating the ground resistance corresponding to the power distribution network to be detected;
when the grounding resistance is a value above a preset resistance value, outputting a high-resistance grounding fault signal;
and when the grounding resistance is smaller than the preset resistance value, adjusting the preset energy threshold value, and re-determining the high-resistance grounding fault detection result of the power distribution network to be detected after the adjusted preset energy threshold value.
6. The utility model provides a detection device of distribution network high resistance ground fault which characterized in that includes:
the acquisition unit is used for acquiring an anchor point modal function corresponding to the power distribution network to be detected;
the acquisition unit is specifically configured to:
searching all maximum value points and all minimum value points of the historical current in the power distribution network to be detected;
determining anchor points corresponding to the power distribution network to be detected according to all the maximum value points and the minimum value points;
interpolation processing is carried out on all the anchor points based on an extrapolation method, so that corresponding anchor point curves are obtained;
performing difference on the historical current and the anchor point curve to obtain an anchor point modal function corresponding to the power distribution network to be detected;
the detection device further includes:
the decomposition unit is used for carrying out multi-layer decomposition on the current signal of the power distribution network to be detected to obtain a full-filter coefficient corresponding to the current signal;
the decomposition unit is specifically used for:
acquiring a current signal and a basic filter of the power distribution network to be detected;
multiplying the current signal by the basic filter to obtain a basic full-filter coefficient corresponding to the basic filter;
updating the basic filter for a preset number of times, calculating a new full filter coefficient corresponding to the new basic filter after each update, and taking the obtained basic full filter coefficient as the full filter coefficient corresponding to the current signal;
the detection device further includes:
the first calculation unit is used for calculating a fraction filter coefficient corresponding to the current signal according to the full filter coefficient and the anchor point modal function;
the calculation formula of the fractional filter coefficient is as follows:
in the formula, nd q For the q-th fractional filter coefficient, I J,q Is the q-th full filter coefficient, f 4 () As anchor point mode function, f 4 (I J,q ) An anchor point modal function corresponding to the q-th full filter coefficient;
the second calculation unit is used for calculating the fractional filter coefficient energy corresponding to the fractional filter coefficient through a preset energy calculation formula;
and the judging unit is used for obtaining the high-resistance ground fault detection result of the power distribution network to be detected according to the comparison result of the fractional filter coefficient energy and the preset energy threshold value.
7. The utility model provides a detection equipment of distribution network high resistance ground fault which characterized in that includes treater and memory;
the memory is used for storing program codes and transmitting the program codes to the processor;
the processor is configured to perform the method for detecting a high-resistance ground fault of a power distribution network according to any one of claims 1 to 5 according to instructions in the program code.
8. A storage medium storing program code for performing the method of detecting a high-resistance ground fault of an electrical distribution network according to any one of claims 1 to 5.
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