CN110542833A - Method and device for positioning high-resistance grounding fault section of power distribution network and storage medium - Google Patents
Method and device for positioning high-resistance grounding fault section of power distribution network and storage medium Download PDFInfo
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Abstract
The invention discloses a method, a device and a storage medium for positioning a high-resistance grounding fault section of a power distribution network, wherein the method comprises the following steps: acquiring zero-mode current wave recording data of each fault fixed-section terminal; selecting a zero-mode current initial wave head according to the zero-mode current wave recording data, and aligning the traveling wave heads of the zero-mode current wave recording data of all the terminals; when the amplitude of the zero-mode current initial wave head is not smaller than the rated current value, calculating product integrals of each terminal and a sampling point of the next terminal after the fault according to the zero-mode current initial wave head, and determining a first ground fault section according to the calculation result to obtain an initial wave head judgment result; performing cross wavelet transformation on the zero-mode current wave recording data acquired by each terminal and the next terminal, and determining a second earth fault section according to the transformation result to obtain a cross wavelet phase judgment result; when the initial wave head judgment result is consistent with the cross wavelet phase judgment result, a fault segmentation result is obtained, the fault section can be accurately judged, and the method has high adaptability.
Description
Technical Field
the invention relates to the technical field of power system fault detection, in particular to a method and a device for positioning a high-resistance grounding fault section of a power distribution network and a storage medium.
background
the fault location of the power distribution network has important significance for the research of the faults of the power distribution network, and the efficient and accurate fault location method is beneficial to improving the reliability of power supply of the power distribution network. At present, the research on the fault analysis and positioning problems of the power transmission network is more perfect, but for the power distribution network, the structure is often more complex, the problems of multi-stage branches, looped networks, short line distance, different grounding modes and the like exist, the difficulty of fault positioning is greatly increased, and particularly for high-resistance grounding faults, the difficulty of fault positioning is higher.
The traditional power distribution network fault positioning method comprises an injection method, an impedance method and a traveling wave method. The injection method injects a specific signal into a line, then detects a fault point reflected wave signal to carry out ranging, a special injection signal source and an auxiliary detection device are required to be configured, and ranging accuracy is greatly influenced by factors such as lead distributed capacitance, grounding resistance and the like. The accuracy of the impedance method is easily affected by the transition resistance and is more reliable only when the line is a uniform transmission line. The traveling wave method comprises a single-ended traveling wave method and a double-ended traveling wave method, wherein the single-ended traveling wave method has difficulty in identifying the wave head of the second reflected traveling wave when the high-resistance grounding fault occurs; the double-end traveling wave method has higher requirement on the data synchronism of the two ends. In addition, the traditional fault location method based on the traveling wave can be theoretically adapted to various fault situations. However, since the speed of the fault traveling wave is approximately equal to the speed of light, even at a sampling frequency of 1MHz, the distance corresponding to each sampling point is 300m, and inherent errors in the conventional method may cause positioning errors of several kilometers, at this time, the requirement on the sampling frequency is extremely high in order to ensure the ranging accuracy.
with the continuous development of wireless communication technology and the continuous improvement of distribution network automation degree, distribution automation terminals are more and more widely applied, and distribution networks also begin to utilize distribution automation terminals to carry out fault location. However, for the existing scheme of judging the fault section by using the distribution automation terminal, the section determining mode is mainly to perform accurate quantitative analysis according to the local information of the distribution network acquired by the terminal. The method has weak capacity of resisting transition resistance, and is very easy to have misjudgment when high-resistance grounding faults occur.
disclosure of Invention
the embodiment of the invention provides a method, a device and a storage medium for positioning a high-resistance ground fault section of a power distribution network, which can effectively solve the problems that the resistance to transition resistance is weak and misjudgment is easy to occur when a high-resistance ground fault occurs in the prior art, can accurately judge the fault section and have high adaptability.
An embodiment of the present invention provides a method for locating a high-resistance ground fault section of a power distribution network, including:
acquiring zero-mode current wave recording data of each fault fixed-section terminal;
selecting a zero-mode current initial wave head according to the zero-mode current wave recording data, and aligning the traveling wave heads of the zero-mode current wave recording data of all the terminals by taking the zero-mode current initial wave head as a reference point;
Judging the amplitude of the zero-mode current initial wave head and the magnitude of a preset rated current value;
When the amplitude of the zero-mode current initial wave head is not smaller than the rated current value, calculating product integrals of each terminal and a sampling point of the next terminal after the fault according to the zero-mode current initial wave head, and determining a first ground fault section according to the calculation result to obtain an initial wave head judgment result;
performing cross wavelet transformation on the zero-mode current wave recording data acquired by each terminal and the next terminal, and determining a second earth fault section according to the transformation result to obtain a cross wavelet phase judgment result;
And when the initial wave head judgment result is consistent with the cross wavelet phase judgment result, obtaining a fault fixed-segment result.
as an improvement of the above scheme, the determining the first ground fault section according to the calculation result to obtain an initial wave head determination result specifically includes:
And when the calculation result is a negative value, determining that the first ground fault section is a section between the terminal corresponding to the calculation result and the subsequent terminal, and obtaining the initial wave head judgment result.
As an improvement of the above scheme, the determining the first ground fault section according to the calculation result to obtain an initial wave head determination result specifically includes:
and when all the calculation results are positive values, determining that the first grounding fault section is a line bus to obtain the initial wave head judgment result.
As an improvement of the above scheme, the performing cross wavelet transform on the zero mode current recorded wave data collected by each terminal and a subsequent terminal, and determining a second ground fault section according to the transform result to obtain a cross wavelet phase determination result specifically includes:
pre-selecting a transformation scale coefficient;
Calculating the phase difference of the cross wavelets collected by each terminal and the next terminal according to the transformation scale coefficient;
calculating a cross wavelet phase difference average value according to the cross wavelet phase difference, and judging whether the cross wavelet phase difference average value is within a preset phase difference threshold value;
when the cross wavelet phase difference average value is within the phase difference threshold value, determining that the second ground fault section is a section between a terminal corresponding to the cross wavelet phase difference average value and a subsequent terminal to obtain a cross wavelet phase judgment result;
And when all the cross wavelet phase difference average values are not within the phase difference threshold value, determining the second ground fault section as a line bus to obtain a cross wavelet phase judgment result.
As an improvement of the above, the method further comprises:
and when the initial wave head judgment result is inconsistent with the cross wavelet phase judgment result, taking the cross wavelet phase judgment result as a fault segmentation result.
As an improvement of the above scheme, the determining the amplitude of the zero mode current initial wave head and the preset rated current value further includes:
And when the amplitude of the zero-mode current initial wave head is smaller than the rated current value, taking the cross wavelet phase determination result as a fault segmentation result.
As an improvement of the above solution, when the initial wave head determination result and the cross wavelet phase determination result are consistent, a fault segmentation result is obtained, further comprising:
and sending a protection control instruction according to the fault section determining result to control the removal of the ground fault section.
Another embodiment of the present invention correspondingly provides a device for locating a high-resistance ground fault section of a power distribution network, including:
The data acquisition module is used for acquiring zero-mode current wave recording data of each fault fixed-section terminal;
The traveling wave head processing module is used for selecting a zero-mode current initial wave head according to the zero-mode current wave recording data, and aligning the traveling wave heads of the zero-mode current wave recording data of all the terminals by taking the zero-mode current initial wave head as a reference point;
the judging module is used for judging the amplitude of the zero-mode current initial wave head and the preset rated current value;
the initial wave head judging module is used for calculating product integrals of sampling points of each terminal and the next terminal after the fault according to the zero-mode current initial wave head when the amplitude of the zero-mode current initial wave head is not smaller than the rated current value, and determining a first ground fault section according to the calculation result to obtain an initial wave head judging result;
the cross wavelet phase judgment module is used for performing cross wavelet transformation on the zero-mode current wave recording data collected by each terminal and the next terminal, and determining a second ground fault section according to the transformation result to obtain a cross wavelet phase judgment result;
And the fault segmentation module is used for obtaining a fault segmentation result when the initial wave head judgment result is consistent with the cross wavelet phase judgment result.
Compared with the prior art, the method and the device for positioning the high-resistance grounding fault section of the power distribution network disclosed by the embodiment of the invention have the following beneficial effects:
Obtaining zero-mode current recording data of each fault fixed-segment terminal, selecting a zero-mode current initial wave head according to the recording data, aligning the traveling wave head of the zero-mode current recording data of each terminal by taking the zero-mode current initial wave head as a reference point, judging the amplitude of the zero-mode current initial wave head and the preset rated current value, when the amplitude of the zero-mode current initial wave head is not less than the rated current value, calculating the product integral of sampling points of each terminal and the next terminal after the fault according to the zero-mode current initial wave head, determining a first ground fault section according to the calculation result to obtain an initial wave head judgment result, performing cross wavelet transformation on the zero-mode current recording data collected by each terminal and the next terminal, determining a second ground fault section according to the transformation result to obtain a cross wavelet phase judgment result, and when the initial wave head judgment result is consistent with the cross wavelet phase judgment result, obtaining a fault fixed-segment result.
Firstly, the invention can effectively solve the problems of weak transition resistance tolerance and easy erroneous judgment when high-resistance grounding fault occurs in the prior art, and when the fault switching-on angle is 10 degrees, the oscillation component in the zero-mode current traveling wave still exists, the phase characteristics are obvious, the dead zone range is small, so that the reliability of fault section positioning is higher, and the accuracy of fault section judgment can be effectively improved.
secondly, the method and the device have strong adaptability, and the fault sections can be accurately found out by the method and the device for different fault positions and different transition resistances.
Moreover, the method has lower requirement on sampling frequency, does not need to adopt zero sequence voltage, can effectively reduce cost, can effectively reduce the difficulty of fault positioning, reduces the error of fault positioning judgment, and has higher engineering application value.
Another embodiment of the present invention provides a high-resistance ground fault section positioning apparatus for a power distribution network, including a processor, a memory, and a computer program stored in the memory and configured to be executed by the processor, where the processor, when executing the computer program, implements the high-resistance ground fault section positioning method for the power distribution network according to the above embodiment of the present invention.
Another embodiment of the present invention provides a storage medium, where the computer-readable storage medium includes a stored computer program, where when the computer program runs, the apparatus where the computer-readable storage medium is located is controlled to execute the method for locating a high-resistance ground fault section of a power distribution network according to the above-described embodiment of the present invention.
Drawings
Fig. 1 is a schematic flowchart of a method for locating a high-resistance ground fault section of a power distribution network according to an embodiment of the present invention;
fig. 2 is a model diagram of an arc suppression coil grounding system according to a first embodiment of the present invention;
Fig. 3 is a schematic structural diagram of a high-resistance ground fault section positioning device for a power distribution network according to a second embodiment of the present invention.
Detailed Description
the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Example one
Referring to fig. 1, a schematic flowchart of a method for locating a high-resistance ground fault section of a power distribution network according to an embodiment of the present invention is shown, where the method includes steps S101 to S106.
S101, acquiring zero-mode current wave recording data of each fault fixed-section terminal.
in an alternative embodiment, in order to ensure a sufficient data window, the zero-mode current of the line within the starting time threshold of the zero-mode current abrupt change is obtained from the zero-mode current recorded wave data. Illustratively, the zero-mode current of all lines is collected within a time range of 5ms before the start of the zero-mode current abrupt change and 20ms after the start, and the sampling rate is fS-10 kHz.
s102, selecting a zero-mode current initial wave head according to the zero-mode current wave recording data, and aligning the traveling wave heads of the zero-mode current wave recording data of all the terminals by taking the zero-mode current initial wave head as a reference point.
in this embodiment, a wave head (or the maximum mode maximum wave head itself) of each line traveling wave, which is larger than the maximum mode maximum 1/3 and appears before the maximum mode maximum wave head, is selected from traveling wave heads of zero-mode current recording data as an initial wave head of zero-mode current. And aligning the zero-mode current recording data of each terminal by taking the initial wave head of the zero-mode current as a reference point so as to enable all the zero-mode current recording data to be close to synchronization.
the method is characterized in that a traveling wave head of each recorded wave data is aligned, two signals are required to be synchronously sampled when the correlation of the two signals is analyzed, but sampling of each fault fixed-section terminal is independent, and synchronous sampling is high in implementation cost. Because the power distribution network line is usually only about 10kM, the propagation time of the current traveling wave on the whole line is about 33 mus, and the phase difference between the head end and the tail end of the zero-mode current traveling wave line which adopts about 10 times of the power frequency is about 6 degrees, the current traveling wave line can be considered to be simultaneously established in the whole line.
s103, judging the amplitude of the zero-mode current initial wave head and the preset rated current value.
in an alternative embodiment, when the amplitude of the zero mode current initial wave head is smaller than the rated current value, the cross wavelet phase determination result is used as a fault segmentation result.
Exemplarily, whether the amplitude of the zero-mode current initial wave head is smaller than 0.1 time of rated current is judged; if yes, go to step S105; if the determination result is no, step S104 is executed.
and S104, when the amplitude of the zero-mode current initial wave head is not smaller than the rated current value, calculating product integrals of each terminal and a sampling point of the next terminal after the fault according to the zero-mode current initial wave head, and determining a first ground fault section according to the calculation result to obtain an initial wave head judgment result.
In this embodiment, the zero-mode current wave in the fault contains a large amount of high-frequency components, and for accurately distinguishing the initial wave head of the zero-mode current, a low-pass filter can be used to filter the high-frequency components. And calculating the integral of the product of sampling points of adjacent terminals by using the initial wave head of the zero-mode current after the low-pass filtering of the terminal within 5ms after the fault occurs.
In an alternative embodiment, when the calculation result is a negative value, the first ground fault section is determined to be a section between the terminal corresponding to the calculation result and a subsequent terminal, and the initial wave head determination result is obtained.
in an optional embodiment, when all the calculation results are positive values, the first ground fault section is determined to be a line bus, and the initial wave head determination result is obtained.
And S105, performing cross wavelet transformation on the zero-mode current recorded wave data acquired by each terminal and the next terminal, and determining a second earth fault section according to the transformation result to obtain a cross wavelet phase judgment result.
In an alternative embodiment, the transform scale coefficients are pre-selected;
Calculating the phase difference of the cross wavelets collected by each terminal and the next terminal according to the transformation scale coefficient;
calculating a cross wavelet phase difference average value according to the cross wavelet phase difference, and judging whether the cross wavelet phase difference average value is within a preset phase difference threshold value;
when the cross wavelet phase difference average value is within the phase difference threshold value, determining that the second ground fault section is a section between a terminal corresponding to the cross wavelet phase difference average value and a subsequent terminal to obtain a cross wavelet phase judgment result;
And when all the cross wavelet phase difference average values are not within the phase difference threshold value, determining the second ground fault section as a line bus to obtain a cross wavelet phase judgment result.
It should be noted that, for the time domain signal with limited energy, the continuous wavelet transform is defined according to the formula; wherein: ψ is a mother wavelet, s (s >0) is a scale operator, τ is a shift operator, and τ represents complex conjugation.
for the energy-limited time domain signals x (t) and y (t), the cross wavelet transform of the two signals is calculated by adopting a formula.
defining a cross wavelet phase according to a formula; the phase difference of two input signals at a scale s and a displacement operator tau is shown; re { Wxy (s, τ) }, Im { Wxy (s, τ) } are the real and imaginary parts of Wxy (s, τ), respectively.
Further, a suitable transformation scale coefficient is selected for phase analysis, and the energy spectrum density is usually the maximum as a criterion, and the relation between the scale coefficient s and the frequency f is f ═ fS/s. Further, calculating the average value of the cross wavelet phase difference under the scale coefficient by using a formula; wherein, the value is the average value of the cross wavelet phase difference, and Ntau is the total point number under the scale coefficient s after the zero-mode current cross wavelet transformation.
In this embodiment, the criterion of protection is: selecting the section with the cross wavelet phase and the adjacent section as a fault section; and if all the section cross wavelet phase differences are equal, determining that the bus is in fault.
And S106, obtaining a fault segmentation result when the initial wave head judgment result is consistent with the cross wavelet phase judgment result.
Further, after step S106, the method further includes:
And sending a protection control instruction according to the fault section determining result to control the removal of the ground fault section.
in an alternative embodiment, when the initial wave head determination result and the cross wavelet phase determination result are not consistent, the cross wavelet phase determination result is used as a fault segmentation result.
It should be noted that, whether the determination results of the two determinations are consistent or not is judged; if not, selecting the judgment result of the cross wavelet phase criterion as a final result, outputting a positioning result and giving an alarm; if the two judgment results are consistent, the two judgment results are used as final results, the positioning result is output, and the fault section is cut off.
Fig. 2 is a schematic diagram of an arc suppression coil grounding system according to a first embodiment of the present invention. An arc suppression coil grounding system model shown in fig. 2 is built in an RTDS real-time digital simulator, and specifically a 10kV arc suppression coil grounding power distribution system. The system has three outgoing lines, the line adopts a mixed line of an overhead line and a cable, and the lengths of L1, L2 and L3 are all 10 km. L1 is a fault line, zone 1 and zone 2 are respectively provided with load branches, LD1 and LD2, zone 3 is also connected with a 4km branch line, and the line end is connected with a load LD 3. The tail end of the feed line L1 is also connected with a load LD 4. Wherein, the loads LD1, LD2 and LD3 are 1MW, the load LD4 is 6MW, and the power factor is 0.95; f1, f2, f3, f4, f5 and f6 are different fault points (each fault point is at the middle point of the section); l1 has 5 fault location terminals Q1, Q2, Q3, Q4, Q5 mounted thereon. Wherein Q1, Q2, Q3, Q4 are equidistantly installed on the feeder line L1, and Q5 is installed on the branch line of the section 3. The arc suppression coil adopts an overcompensation mode, the detuning degree is-6%, and the equivalent reactance of the arc suppression coil is LC (0.2945H). The overhead line model refers to LGJ-180 standard parameters, and the capacitance of a unit-length line is CT which is 0.05 mu F; the cable line model refers to YJV22-240 standard parameters, and the line capacitance per unit length is CL 0.37 μ F.
further, the method is applied to the arc suppression coil grounding system model, and the positioning method of the high-resistance grounding fault section of the power distribution network is verified based on RTDS. Assuming that the sampling frequency of each terminal is 10kHz, the extracted data time window is half cycle before the fault and one cycle after the fault. The following table 1 shows phase differences and fault section-fixing results of adjacent terminals under different transition resistances, different fault positions and different fault closing angles.
from the comprehensive results in table 1, the method for locating the high-resistance grounding fault section of the power distribution network can accurately find out the fault section aiming at different fault positions and different transition resistances, and has strong adaptability and high accuracy.
the embodiment of the invention provides a method and a device for positioning a high-resistance ground fault section of a power distribution network, which are characterized in that zero-mode current wave recording data of each fault fixed-section terminal are obtained, a zero-mode current initial wave head is selected according to the wave recording data, the zero-mode current initial wave head is taken as a reference point, a traveling wave head of the zero-mode current wave recording data of each terminal is aligned, the amplitude of the zero-mode current initial wave head and a preset rated current value are judged, when the amplitude of the zero-mode current initial wave head is not less than the rated current value, product integrals of sampling points of each terminal and the next terminal after the fault are calculated according to the zero-mode current initial wave head, a first ground fault section is determined according to the calculation result, an initial wave head determination result is obtained, and cross wavelet transformation is carried out on the zero-mode current wave recording data collected by each terminal and the next terminal, and determining a second earth fault section according to the transformation result to obtain a cross wavelet phase judgment result, and obtaining a fault section fixing result when the initial wave head judgment result is consistent with the cross wavelet phase judgment result. Firstly, the invention can effectively solve the problems of weak transition resistance tolerance and easy erroneous judgment when high-resistance grounding fault occurs in the prior art, and when the fault switching-on angle is 10 degrees, the oscillation component in the zero-mode current traveling wave still exists, the phase characteristics are obvious, the dead zone range is small, so that the reliability of fault section positioning is higher, and the accuracy of fault section judgment can be effectively improved. Secondly, the method and the device have strong adaptability, and the fault sections can be accurately found out by the method and the device for different fault positions and different transition resistances. Moreover, the method has lower requirement on sampling frequency, does not need to adopt zero sequence voltage, can effectively reduce cost, can effectively reduce the difficulty of fault positioning, reduces the error of fault positioning judgment, and has higher engineering application value.
example two
Referring to fig. 3, a schematic structural diagram of a high resistance ground fault section positioning device for a power distribution network according to a second embodiment of the present invention includes:
The data acquisition module 201 is configured to acquire zero-mode current wave recording data of each fault fixed-segment terminal;
the traveling wave head processing module 202 is configured to select a zero-mode current initial wave head according to the zero-mode current wave recording data, and align the traveling wave heads of the zero-mode current wave recording data of each terminal with the zero-mode current initial wave head as a reference point;
the judging module 203 is configured to judge the amplitude of the zero-mode current initial wave head and a preset rated current value;
An initial wave head determining module 204, configured to calculate, according to the zero-mode current initial wave head, product integrals of sampling points of each terminal and a subsequent terminal after the fault, and determine a first ground fault section according to the calculation result, when the amplitude of the zero-mode current initial wave head is not smaller than the rated current value, so as to obtain an initial wave head determining result;
A cross wavelet phase determination module 205, configured to perform cross wavelet transformation on the zero mode current recorded wave data collected by each terminal and a subsequent terminal, and determine a second ground fault section according to a transformation result to obtain a cross wavelet phase determination result;
and a fault segmentation module 206, configured to obtain a fault segmentation result when the initial wave head determination result is consistent with the cross wavelet phase determination result.
preferably, the initial wave head determining module 204 includes:
and the first initial wave head judging unit is used for determining the first ground fault section as a section between the terminal corresponding to the calculation result and the subsequent terminal when the calculation result is a negative value, so as to obtain the initial wave head judging result.
Preferably, the initial wave head determining module 204 includes:
and the second initial wave head judging unit is used for determining the first ground fault section as a line bus when all the calculation results are positive values, so as to obtain the initial wave head judging result.
preferably, the cross wavelet phase determination module 205 includes:
The scale selection unit is used for selecting a transformation scale coefficient in advance;
The cross wavelet phase difference calculating unit is used for calculating the cross wavelet phase difference collected by each terminal and the next terminal according to the transformation scale coefficient;
The cross wavelet phase difference average value calculating unit is used for calculating a cross wavelet phase difference average value according to the cross wavelet phase difference and judging whether the cross wavelet phase difference average value is within a preset phase difference threshold value or not;
The first cross wavelet phase determination unit is used for determining that the second ground fault section is a section between a terminal corresponding to the cross wavelet phase difference average value and a subsequent terminal when the cross wavelet phase difference average value is within the phase difference threshold value, so as to obtain a cross wavelet phase determination result;
and the second cross wavelet phase determination unit is used for determining the second ground fault section as a line bus to obtain a cross wavelet phase determination result when all the cross wavelet phase difference average values are not within the phase difference threshold value.
Preferably, the fault segmentation module 206 further includes:
And the fault segmentation determining unit is used for taking the cross wavelet phase determination result as a fault segmentation result when the initial wave head determination result is inconsistent with the cross wavelet phase determination result.
Preferably, the judging module 203 includes:
And the zero-mode current initial wave head amplitude judgment unit is used for taking the cross wavelet phase judgment result as a fault segmentation result when the amplitude of the zero-mode current initial wave head is smaller than the rated current value.
Preferably, the fault segmentation module 206 further includes:
and the earth fault section cutting unit is used for sending a protection control instruction to control cutting of the earth fault section according to the fault section fixing result.
The positioning device for a high-resistance ground fault section of a power distribution network provided in the second embodiment is used for executing the steps of the positioning method for a high-resistance ground fault section of a power distribution network in any one of the above embodiments, and working principles and beneficial effects of the two are in one-to-one correspondence, so that details are not repeated.
The high resistance earth fault section positioning device of the power distribution network of the embodiment comprises: a processor, a memory, and a computer program stored in and executable on the memory, such as a power distribution network high resistance ground fault section locating program. The processor, when executing the computer program, implements the steps in each of the above embodiments of the method for locating a high impedance earth fault section of a power distribution network, such as step S104 shown in fig. 1. Alternatively, the processor implements the functions of the modules/units in the above device embodiments when executing the computer program, for example, the initial wave head determining module 204.
illustratively, the computer program may be partitioned into one or more modules/units that are stored in the memory and executed by the processor to implement the invention. The one or more modules/units may be a series of instruction segments of a computer program capable of performing specific functions, and the instruction segments are used for describing the execution process of the computer program in the positioning device for the high-resistance earth fault section of the power distribution network.
The high-resistance grounding fault section positioning device of the power distribution network can be computing equipment such as a desktop computer, a notebook computer, a palm computer and a cloud server. The power distribution network high resistance earth fault section positioning device can comprise, but is not limited to, a processor and a memory. It will be understood by those skilled in the art that the schematic diagram is merely an example of the power distribution network high resistance ground fault section locating device, and does not constitute a limitation of the power distribution network high resistance ground fault section locating device, and may include more or less components than those shown, or combine some components, or different components, for example, the power distribution network high resistance ground fault section locating device may further include an input-output device, a network access device, a bus, etc.
The Processor may be a Central Processing Unit (CPU), other general purpose Processor, a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), an off-the-shelf Programmable Gate Array (FPGA) or other Programmable logic device, discrete Gate or transistor logic, discrete hardware components, etc. The general processor may be a microprocessor or the processor may be any conventional processor or the like, and the processor is a control center of the power distribution network high impedance ground fault section locating device, and various interfaces and lines are used for connecting various parts of the whole power distribution network high impedance ground fault section locating device.
The memory can be used for storing the computer programs and/or modules, and the processor can realize various functions of the distribution network high-resistance ground fault section positioning device by running or executing the computer programs and/or modules stored in the memory and calling the data stored in the memory. The memory may mainly include a storage program area and a storage data area, wherein the storage program area may store an operating system, an application program required by at least one function (such as a sound playing function, an image playing function, etc.), and the like; the storage data area may store data (such as audio data, a phonebook, etc.) created according to the use of the cellular phone, and the like. In addition, the memory may include high speed random access memory, and may also include non-volatile memory, such as a hard disk, a memory, a plug-in hard disk, a Smart Media Card (SMC), a Secure Digital (SD) Card, a Flash memory Card (Flash Card), at least one magnetic disk storage device, a Flash memory device, or other volatile solid state storage device.
The module/unit integrated with the power distribution network high-resistance earth fault section positioning device can be stored in a computer readable storage medium if the module/unit is implemented in the form of a software functional unit and sold or used as a stand-alone product. Based on such understanding, all or part of the flow of the method according to the embodiments of the present invention may also be implemented by a computer program, which may be stored in a computer-readable storage medium, and when the computer program is executed by a processor, the steps of the method embodiments may be implemented. Wherein the computer program comprises computer program code, which may be in the form of source code, object code, an executable file or some intermediate form, etc. The computer-readable medium may include: any entity or device capable of carrying the computer program code, recording medium, usb disk, removable hard disk, magnetic disk, optical disk, computer Memory, Read-Only Memory (ROM), Random Access Memory (RAM), electrical carrier wave signals, telecommunications signals, software distribution medium, and the like. It should be noted that the computer readable medium may contain content that is subject to appropriate increase or decrease as required by legislation and patent practice in jurisdictions, for example, in some jurisdictions, computer readable media does not include electrical carrier signals and telecommunications signals as is required by legislation and patent practice.
It should be noted that the above-described device embodiments are merely illustrative, where the units described as separate parts may or may not be physically separate, and the parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of the present embodiment. In addition, in the drawings of the embodiment of the apparatus provided by the present invention, the connection relationship between the modules indicates that there is a communication connection between them, and may be specifically implemented as one or more communication buses or signal lines. One of ordinary skill in the art can understand and implement it without inventive effort.
while the foregoing is directed to the preferred embodiment of the present invention, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention.
Claims (10)
1. A method for positioning a high-resistance grounding fault section of a power distribution network is characterized by comprising the following steps:
acquiring zero-mode current wave recording data of each fault fixed-section terminal;
Selecting a zero-mode current initial wave head according to the zero-mode current wave recording data, and aligning the traveling wave heads of the zero-mode current wave recording data of all the terminals by taking the zero-mode current initial wave head as a reference point;
judging the amplitude of the zero-mode current initial wave head and the magnitude of a preset rated current value;
when the amplitude of the zero-mode current initial wave head is not smaller than the rated current value, calculating product integrals of each terminal and a sampling point of the next terminal after the fault according to the zero-mode current initial wave head, and determining a first ground fault section according to the calculation result to obtain an initial wave head judgment result;
performing cross wavelet transformation on the zero-mode current wave recording data acquired by each terminal and the next terminal, and determining a second earth fault section according to the transformation result to obtain a cross wavelet phase judgment result;
and when the initial wave head judgment result is consistent with the cross wavelet phase judgment result, obtaining a fault fixed-segment result.
2. The method for locating a high-resistance ground fault section of a power distribution network according to claim 1, wherein the determining a first ground fault section according to the calculation result to obtain an initial wave head determination result specifically comprises:
And when the calculation result is a negative value, determining that the first ground fault section is a section between the terminal corresponding to the calculation result and the subsequent terminal, and obtaining the initial wave head judgment result.
3. The method for locating a high-resistance ground fault section of a power distribution network according to claim 1, wherein the determining a first ground fault section according to the calculation result to obtain an initial wave head determination result specifically comprises:
And when all the calculation results are positive values, determining that the first grounding fault section is a line bus to obtain the initial wave head judgment result.
4. The method for locating a high-resistance ground fault section of a power distribution network according to claim 1, wherein the step of performing cross wavelet transformation on zero-mode current recorded wave data collected by each terminal and a subsequent terminal and determining a second ground fault section according to a transformation result to obtain a cross wavelet phase determination result specifically comprises the steps of:
Pre-selecting a transformation scale coefficient;
calculating the phase difference of the cross wavelets collected by each terminal and the next terminal according to the transformation scale coefficient;
Calculating a cross wavelet phase difference average value according to the cross wavelet phase difference, and judging whether the cross wavelet phase difference average value is within a preset phase difference threshold value;
when the cross wavelet phase difference average value is within the phase difference threshold value, determining that the second ground fault section is a section between a terminal corresponding to the cross wavelet phase difference average value and a subsequent terminal to obtain a cross wavelet phase judgment result;
And when all the cross wavelet phase difference average values are not within the phase difference threshold value, determining the second ground fault section as a line bus to obtain a cross wavelet phase judgment result.
5. The method for locating a high resistance to ground fault section of a power distribution network of claim 1, wherein the method further comprises:
and when the initial wave head judgment result is inconsistent with the cross wavelet phase judgment result, taking the cross wavelet phase judgment result as a fault segmentation result.
6. the method for locating a high-resistance ground fault section of a power distribution network according to claim 1, wherein the determining the magnitude of the zero-mode current initial wave head and a preset rated current value further comprises:
and when the amplitude of the zero-mode current initial wave head is smaller than the rated current value, taking the cross wavelet phase determination result as a fault segmentation result.
7. The method for locating a high impedance earth fault section of a power distribution network according to claim 1, wherein when the initial wave head determination result and the cross wavelet phase determination result are consistent, a fault segmentation result is obtained, further comprising:
and sending a protection control instruction according to the fault section determining result to control the removal of the ground fault section.
8. A distribution network high resistance ground fault section positioner, its characterized in that includes:
The data acquisition module is used for acquiring zero-mode current wave recording data of each fault fixed-section terminal;
The traveling wave head processing module is used for selecting a zero-mode current initial wave head according to the zero-mode current wave recording data, and aligning the traveling wave heads of the zero-mode current wave recording data of all the terminals by taking the zero-mode current initial wave head as a reference point;
the judging module is used for judging the amplitude of the zero-mode current initial wave head and the preset rated current value;
the initial wave head judging module is used for calculating product integrals of sampling points of each terminal and the next terminal after the fault according to the zero-mode current initial wave head when the amplitude of the zero-mode current initial wave head is not smaller than the rated current value, and determining a first ground fault section according to the calculation result to obtain an initial wave head judging result;
The cross wavelet phase judgment module is used for performing cross wavelet transformation on the zero-mode current wave recording data collected by each terminal and the next terminal, and determining a second ground fault section according to the transformation result to obtain a cross wavelet phase judgment result;
And the fault segmentation module is used for obtaining a fault segmentation result when the initial wave head judgment result is consistent with the cross wavelet phase judgment result.
9. A distribution network high resistance ground fault section locating device, comprising a processor, a memory and a computer program stored in the memory and configured to be executed by the processor, the processor implementing the distribution network high resistance ground fault section locating method according to any one of claims 1 to 7 when executing the computer program.
10. a computer-readable storage medium, comprising a stored computer program, wherein when the computer program is executed, the computer-readable storage medium controls an apparatus to execute the method according to any one of claims 1 to 7.
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| CN112083283B (en) * | 2020-09-07 | 2021-05-25 | 昆明理工大学 | Power distribution network fault section positioning method based on fault component frequency band distribution difference |
| CN112083284B (en) * | 2020-09-07 | 2021-10-12 | 昆明理工大学 | Method for identifying fault section and fault branch of current collecting line of wind power plant |
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| CN112345968A (en) * | 2020-11-10 | 2021-02-09 | 国网江苏省电力有限公司盐城供电分公司 | DC system ground fault comprehensive detection method |
| CN112731053A (en) * | 2020-12-18 | 2021-04-30 | 华南理工大学 | High-resistance grounding fault section positioning method for resonance grounding power distribution network |
| CN113030648A (en) * | 2021-03-19 | 2021-06-25 | 国网河北省电力有限公司邢台供电分公司 | Method and device for determining position of fault point of power cable and terminal equipment |
| CN114878971A (en) * | 2022-05-31 | 2022-08-09 | 国网北京市电力公司 | Method, device, equipment and medium for positioning fault point of power distribution network |
| CN114878971B (en) * | 2022-05-31 | 2024-01-30 | 国网北京市电力公司 | Power distribution network fault point positioning method, device, equipment and medium |
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