CN117686843A - Power distribution network fault line selection method and system based on waveform high-order accumulation reconstruction - Google Patents

Abstract

The invention relates to the technical field of relay protection of power systems, in particular to a power distribution network fault line selection method, a system and a readable storage medium based on waveform high-order accumulation reconstruction, wherein the method comprises the following steps: acquiring the zero sequence voltage of a bus in a power distribution network and the actual measurement zero sequence current of each feeder; constructing a zero sequence current higher accumulated waveform corresponding to each feeder line; calculating a waveform integral value after reconstruction of each feeder line according to the high-order accumulated waveform of the zero sequence current; and determining fault feeder lines in the feeder lines according to the waveform curve integral values of the high-order accumulation of the zero-sequence currents. Aiming at the distribution network in a small-current grounding mode, the method can effectively solve the problem of difficult fault line selection caused by small fault grounding current.

Description

Distribution network fault line selection method and system based on high-order accumulation and reconstruction of waveforms

Technical field

The invention relates to the technical field of power system relay protection, and in particular to a distribution network fault line selection method, system and readable storage medium based on high-order accumulation and reconstruction of waveforms.

Background technique

The distribution network is an important part that connects the power grid and users. The stability and safety of its operation are closely related to people's lives, and it plays an important role in promoting social and economic development. In my country, the distribution network generally adopts the working mode of neutral point grounding through arc suppression coil or neutral point grounding through small resistance. There are many types of faults, among which single-phase grounding faults account for more than 90% of all accidents in the power grid. When a single-phase ground fault occurs in the system, the ground current is very small, the number of feeders is large, and the fault characteristics are sometimes not obvious, which brings greater difficulties to fault detection. Therefore, the single-phase ground fault line selection method must be paid attention to. In order to improve the reliability of power supply and ensure the safe and stable operation of the power grid, it is particularly important to study efficient, accurate and reliable single-phase ground fault line selection methods.

In related technical solutions for distribution networks, the neutral point of the distribution network generally adopts an ungrounded or resonant grounding method. When a single-phase ground fault occurs, the current flowing through the fault point is very small without affecting the symmetry of the system. , can run with faults for a period of time, so it is called a small current grounded distribution network. The main advantage of a small-current grounded distribution network is that the current flowing into the earth is small, and some interfering transient faults do not cause protection actions, which effectively improves the reliability of power supply.

However, when the inventor conceived and implemented this solution, he found that this grounding method has the following shortcomings: when a single-phase ground fault occurs in the distribution network under the low-current grounding method, the fault characteristics are not obvious, making it difficult to achieve accurate line selection. This invention uses the ratio of the integrated value of the high-order accumulated reconstructed waveform of each feeder in the distribution network as a criterion to determine whether the feeder is a faulty line or a sound line. By using high-order accumulated waveform processing, the zero sequence can be highlighted. The fault characteristics of the current; at the same time, the integral is used to calculate the reconstructed waveform area, which can more accurately depict the distortion characteristics of the fault zero-sequence current waveform, amplify the weak changes, and use the reconstructed area ratio of the faulty line and the healthy line to This serves as the basis for fault line selection.

Contents of the invention

The main purpose of the present invention is to provide a distribution network fault line selection method based on high-order accumulation and reconstruction of waveforms, aiming to solve the problem of how to improve the accuracy of distribution network line selection.

In order to achieve the above objectives, the present invention provides a distribution network fault line selection method based on high-order accumulation and reconstruction of waveforms. The method includes:

Obtain the zero-sequence voltage of the bus in the distribution network and the measured zero-sequence current of each feeder;

Construct the high-order accumulation waveform of zero-sequence current corresponding to each feeder;

According to the high-order accumulated waveform of the zero-sequence current, calculate the reconstructed waveform integral value of each feeder;

According to the integrated value of the high-order accumulated waveform curve of the zero-sequence current, the faulty feeder in each of the feeders is determined.

Optionally, the steps of obtaining the zero-sequence voltage of the busbar and the measured zero-sequence current of each feeder in the distribution network include:

By using voltage transformers (PT) and current transformers (CT), the zero-sequence voltage of the distribution network bus and the zero-sequence current of each feeder are measured and recorded in real time during faults.

When the instantaneous value of the bus zero sequence voltage is greater than the preset voltage threshold, an electrical signal is sent to the fault wave recording and line selection device to activate the fault wave recording and line selection device.

Optionally, the steps of constructing the high-order accumulated waveform of zero sequence current corresponding to each feeder include:

Cube the zero-sequence current corresponding to each feeder in the distribution network;

The five sampling points of the zero-sequence current after the cubic operation are enhanced and accumulated, and the cycle is accumulated to the end to obtain a new set of zero-sequence current sequences, and the high-order accumulation-transformed feeder zero-sequence current with enhanced amplitude and unchanged polarity is obtained. , its calculation method is as follows:

In the formula: Assume that the zero sequence current has a total sampling points, for , for the first Feeder zero sequence current.

Based on the calculated value of its high-order accumulation, the high-order accumulation reconstructed waveform diagram of the zero-sequence current is drawn.

Optionally, based on the zero-sequence current high-order accumulated waveform, the step of calculating the reconstructed waveform integral value of each feeder includes:

Perform an integral operation on the high-order accumulated waveform of the zero-sequence current to calculate the integral value of the high-order accumulated waveform of the zero-sequence current;

In the formula: Reconstructed waveform for high-order accumulation, is the total sampling points, for a certain feeder.

Optionally, the step of determining the faulty feeder in each of the feeders according to the integrated value of the high-order accumulated waveform curve of the zero-sequence current includes:

Perform an integral operation on the high-order accumulated zero-sequence currents of all feeders and perform an integral operation on the reconstructed waveform to obtain the integral value of the reconstructed waveform;

Calculate whether the ratio of the high-order accumulated reconstructed waveform integral value of any feeder to the high-order accumulated reconstructed waveform integral value of other feeders is greater than the set threshold;

If it is greater than the value, the feeder is judged to be a faulty feeder;

In the formula: for feeder The integrated value of the waveform after high-order accumulation, for feeder The integrated value of the waveform after high-order accumulation, and For any feeder in the distribution network, there are feeder line, is the integral ratio threshold, which is generally taken as 1.5. If the above formula is satisfied, then the The feeder is a faulty feeder.

If the ratio is less than the set threshold, determine the The feeders are sound feeders.

In addition, to achieve the above objectives, the present invention also provides a distribution network fault line selection system based on high-order accumulation and reconstruction of waveforms. The fault line selection system of the distribution network includes:

The data acquisition module is used to obtain the zero-sequence voltage of the busbar and the zero-sequence current of each feeder in the distribution network;

The numerical calculation module, based on the actual zero-sequence current of each feeder, first cubes and then accumulates every five sampling points into one data point to complete the high-order accumulation calculation of the waveform; calculates the integral value of each feeder after the high-order accumulation waveform , and calculate the ratio between any feeder and compare it with the set threshold.

A logical judgment module is used to determine the faulty feeder based on the reconstructed integral value ratio of any feeder.

Optionally, the data collection module includes:

Data acquisition unit, used to collect the bus zero-sequence voltage and the zero-sequence current of each feeder in real time;

The analog-to-digital conversion unit is used to convert the collected instantaneous values of the bus zero-sequence voltage signal and zero-sequence current signal into the digital value of the digital signal.

Optionally, the numerical calculation module also includes:

Signal calculation unit: used to construct a start signal when the instantaneous value of the collected bus zero-sequence voltage is greater than the preset voltage threshold;

Start calculation unit: used to start the line selection device when the instantaneous value of the collected bus zero sequence voltage is greater than the preset voltage threshold;

High-order accumulation calculation unit: used to realize high-order accumulation and reconstruction of waveforms;

Integral operation calculation unit: used to calculate the integral value of the high-order accumulated reconstructed waveform of each feeder;

Integral ratio calculation unit: used to calculate the ratio of the integral value of any feeder to the integral value of other feeders.

Optionally, the logical judgment module also includes:

The bus zero sequence voltage judgment unit is used to determine whether the instantaneous value of the bus zero sequence voltage is greater than the preset voltage threshold;

Among them, if yes, start the high-order accumulation calculation unit, integral operation calculation unit and integral ratio calculation unit;

The fault line selection judgment unit determines whether the ratio of the high-order accumulated reconstructed waveform integral value of any feeder to the high-order accumulated reconstructed waveform integral value of other feeders is greater than the set threshold;

If the value is greater than the value, the target feeder is determined to be a faulty feeder; if the value is less than the value, the target feeder is determined to be a healthy feeder.

In addition, in order to achieve the above object, the present invention also provides a computer-readable storage medium, the computer-readable storage medium stores a fault line selection program of the distribution network, and the fault line selection program of the distribution network is processed When the controller is executed, the steps of implementing the distribution network fault line selection method based on waveform high-order accumulation reconstruction as mentioned above are implemented.

Embodiments of the present invention provide a distribution network fault line selection method, system and computer-readable storage medium based on high-order accumulation and reconstruction of waveforms. This method is oriented to the distribution network grounding method (grounding through arc suppression coil, grounding through small resistance etc.), the high-order accumulated zero-sequence current waveform integral value of each feeder in the distribution network is used as the criterion. High-order accumulation can not only enhance the amplitude, but also has the ability to maintain the number; use the zero-sequence current as a According to this method, this method has high sensitivity and fast speed in identifying faults, and requires fewer sensors than normal three-phase sensors. The integral operation can better reflect the global changes compared with the amplitude, and the judgment of fault line selection is more accurate.

Description of the drawings

Figure 1 is a schematic structural diagram of a fault line selection system of a distribution network according to an embodiment of the present invention;

Figure 2 is an example model built based on PSCAD;

Figure 3 is a schematic flow chart of the distribution network fault line selection method based on high-order waveform accumulation and reconstruction according to the present invention;

Figure 4 shows the zero-sequence current waveform diagram of normal lines in the distribution network;

Figure 5 shows the zero-sequence current waveform of the fault line in the distribution network;

Figure 6 is a high-order accumulated reconstructed waveform diagram of the zero-sequence current of each feeder.

The realization of the purpose, functional features and advantages of the present invention will be further described with reference to the embodiments and the accompanying drawings.

Detailed ways

In order to better understand the above technical solutions, exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that the disclosure will be more thorough, and the scope of the disclosure will be fully conveyed to those skilled in the art.

As an implementation solution, FIG. 1 is a schematic architectural diagram of a fault line selection system of a distribution network involved in an embodiment of the present invention.

As shown in Figure 1, the system includes a data acquisition module 101, a numerical calculation module 102 and a logical judgment module 103. Among them, the data acquisition module 101 is used to obtain the zero-sequence voltage of the bus in the distribution network and the zero-sequence current of each feeder; the numerical calculation module 102 first calculates the zero-sequence current of each feeder based on the actual acquisition, first in cubes and then in each Five sampling points are accumulated into one data point to complete the high-order accumulation calculation of the waveform; calculate the integral value after the high-order accumulation waveform of each feeder, and calculate the ratio between any feeder and compare it with the set threshold; logical judgment Module 103 is used to determine the faulty feeder according to the reconstructed integral value ratio of any feeder. in:

The data acquisition module 101 may include a data acquisition unit 1011 and an analog-to-digital conversion unit 1012. The data acquisition unit 1011 is used to collect the bus zero-sequence voltage and the zero-sequence current of each feeder in real time; the analog-to-digital conversion unit 1012 is used to convert the collected instantaneous values of the bus zero-sequence voltage signal and zero-sequence current signal into digital signals. Numeric value.

The numerical calculation module 102 may include a startup calculation unit 1021, a high-order accumulation calculation unit 1022, an integral operation calculation unit 1023, and an integral ratio calculation unit 1024. The starting calculation unit 1021 is used to start the line selection device when the instantaneous value of the collected bus zero sequence voltage is greater than the preset voltage threshold; the high-order accumulation calculation unit 1022 is used to realize the high-order accumulation and reconstruction of the waveform; the integral operation calculation unit 1023 It is used to calculate the integral value of the high-order accumulated reconstructed waveform of each feeder; the integral ratio calculation unit 1024 is used to calculate the ratio of the integral value of any feeder to the integral value of other feeders.

The logic judgment module 103 may include a bus zero sequence voltage judgment unit 1031 and a fault line selection judgment unit 1032. The bus zero-sequence voltage judgment unit 1031 is used to determine whether the instantaneous value of the bus zero-sequence voltage is greater than the preset voltage threshold; if so, start the high-order accumulation calculation unit, the integral operation calculation unit and the integral ratio calculation unit; fault line selection judgment Unit 1032 is used to determine whether the ratio of the high-order accumulated reconstructed waveform integral value of any feeder to the high-order accumulated reconstructed waveform integral value of other feeders is greater than the set threshold; if it is greater, the target feeder is judged to be a fault feeder; If it is less than, the target feeder is judged to be a healthy feeder. .

In addition, the fault selection system of the distribution network shown in Figure 1 also includes a memory 104 and a processor 105. The memory 104 can be a high-speed RAM memory or a stable memory (non-volatile memory), such as a disk memory. The memory 104 is used to store the fault line selection program of the distribution network as a computer-readable storage medium, and the processor 105 can be used to call the fault line selection program of the distribution network stored in the memory 104 and perform the following operations:

Obtain the zero-sequence voltage of the bus in the distribution network and obtain the measured zero-sequence current of each feeder;

Construct the high-order accumulation waveform of zero-sequence current corresponding to each feeder;

According to the high-order accumulated waveform of the zero-sequence current, calculate the reconstructed waveform integral value of each feeder;

According to the integrated value of the high-order accumulated waveform curve of the zero-sequence current, the faulty feeder in each of the feeders is determined.

In the embodiment, when the processor 105 calls the fault line selection program of the distribution network stored in the memory 104, the following operations are performed:

By using voltage transformers (PT) and current transformers (CT), the zero-sequence voltage of the distribution network bus and the zero-sequence current of each feeder are measured and recorded in real time during faults.

When the instantaneous value of the bus zero sequence voltage is greater than the preset voltage threshold, an electrical signal is sent to the fault wave recording and line selection device to activate the fault wave recording and line selection device.

In the embodiment, when the processor 105 calls the fault line selection program of the distribution network stored in the memory 104, the following operations are performed:

Cube the zero-sequence current corresponding to each feeder in the distribution network;

The five sampling points of the zero-sequence current after the cubic operation are enhanced and accumulated, and the cycle is accumulated to the end to obtain a new set of zero-sequence current sequences, and the high-order accumulation-transformed feeder zero-sequence current with enhanced amplitude and unchanged polarity is obtained. , its calculation method is as follows:

In the formula: Assume that the zero sequence current has a total sampling points, for , for the first Feeder zero sequence current.

Based on the calculated value of its high-order accumulation, the high-order accumulation reconstructed waveform diagram of the zero-sequence current is drawn.

In the embodiment, when the processor 105 calls the fault line selection program of the distribution network stored in the memory 104, the following operations are performed:

Perform an integral operation on the high-order accumulated waveform of the zero-sequence current to calculate the integral value of the high-order accumulated waveform of the zero-sequence current;

In the formula: Reconstructed waveform for high-order accumulation, is the total sampling points, for a certain feeder.

In the embodiment, when the processor 105 calls the fault line selection program of the distribution network stored in the memory 104, the following operations are performed:

Perform an integral operation on the high-order accumulated zero-sequence currents of all feeders and perform an integral operation on the reconstructed waveform to obtain the integral value of the reconstructed waveform;

Calculate whether the ratio of the high-order accumulated reconstructed waveform integral value of any feeder to the high-order accumulated reconstructed waveform integral value of other feeders is greater than the set threshold;

If it is greater than the value, the feeder is judged to be a faulty feeder;

In the formula: for feeder The integrated value of the waveform after high-order accumulation, for feeder The integrated value of the waveform after high-order accumulation, and For any feeder in the distribution network, there are feeder line, is the integral ratio threshold, which is generally taken as 1.5. If the above formula is satisfied, then the The feeder is a faulty feeder.

If the ratio is less than the set threshold, determine the The feeders are sound feeders.

In addition, those skilled in the art can understand that the architecture of the fault line selection system of the distribution network shown in Figure 1 does not constitute a limitation on the fault line selection system of the distribution network, and may include more or less than what is shown in the figure. components, or combinations of certain components, or different arrangements of components.

Based on the hardware architecture of the distribution network fault line selection system based on power system relay protection technology, an embodiment of the distribution network fault line selection method based on waveform high-order accumulation reconstruction is proposed.

Referring to Figure 2, the present invention builds an embodiment distribution line model in PSCAD, with a total of 4 feeders, L1 and L4 are overhead lines, L2 and L3 are cable lines, the sampling frequency is 10kHz, and a single-phase metal is set in the L1 section of the overhead line Ground fault.

Referring to Figure 3, Figure 3 is a specific implementation flow chart of a distribution network fault line selection method and system based on high-order waveform accumulation and reconstruction provided by the present invention.

Step S10: Obtain the zero-sequence voltage of the bus in the distribution network and obtain the measured zero-sequence current of each feeder;

Figure 4 is a zero-sequence current waveform diagram of a faulty line in a distribution network; Figure 5 is a zero-sequence current waveform diagram of a normal line in a distribution network;

It should be noted that this embodiment is aimed at the small current grounding system of the distribution network and only requires a zero-sequence current transformer, which is lower in cost than using a three-phase current transformer.

Step S20, construct the high-order accumulated waveform of zero sequence current corresponding to each feeder;

In this embodiment, after the measured feeder zero-sequence current is obtained, the cubic operation of the zero-sequence current waveform is first performed to make the fault mutation amount more obvious, and then the accumulation operation of every five sampling points is performed to complete the waveform reconstruction. . By amplifying the zero-sequence current waveform of a faulty feeder, the fault characteristics are more obvious and can be better distinguished from a healthy feeder.

Step S30: Calculate the reconstructed waveform integral value of each feeder according to the high-order accumulated waveform of the zero-sequence current;

Calculate the high-order accumulated waveform integral value of the zero-sequence current corresponding to each feeder. The high-order accumulated waveform integral value of the zero-sequence current is represented by a value obtained by integrating the reconstructed zero-sequence current waveform of the feeder. It is usually used to represent the feeder. The total amount of fault characteristics in a certain period of time. In this embodiment, by integrating the high-order accumulated waveform of the zero-sequence current of each feeder, the magnitude of the zero-sequence current mutation of the feeder during the fault period can be obtained. , and then determine whether there is a fault in the feeder.

Step S40: Determine the faulty feeder in each of the feeders according to the integrated value of the high-order accumulated waveform curve of the zero-sequence current;

In the technical solution provided by this embodiment, the high-order accumulated waveform integral value of each feeder in the distribution network is used as a criterion to determine whether the feeder is a faulty line. Since only the zero-sequence current of the line only needs to be measured, The amount of data information required is small, and the sensing equipment required is less than that of measuring three phases. The difference between faulty feeders and normal feeders can be highlighted through high order and accumulation. Therefore, for fault grounding in the small current grounding mode of the distribution network When the current is small, accurate line selection can be achieved.

Further, in this embodiment, step S20 includes:

Step S21: Cube the zero-sequence current corresponding to each feeder in the distribution network;

Step S22: Enhance and accumulate the five sampling points of the zero-sequence current after the cubic operation. The cycle is accumulated to the end to obtain a new set of zero-sequence current sequences. The high-order accumulation transform feeder zero with enhanced amplitude and unchanged polarity is obtained. The sequence current amount is calculated as follows:

In the formula: Assume that the zero sequence current has a total sampling points, for , for the first Feeder zero sequence current.

Step S23: Draw a high-order accumulated reconstructed waveform diagram of the zero-sequence current based on the calculated value of the high-order accumulated value.

Further, in this embodiment, step S30 includes:

Step S31, perform an integral operation on the high-order accumulated waveform of the zero-sequence current, and calculate the integral value of the high-order accumulated waveform of the zero-sequence current;

In the formula: Reconstructed waveform for high-order accumulation, is the total sampling points, for a certain feeder.

Figure 6 is a high-order accumulated reconstructed waveform diagram of the zero-sequence current of each feeder according to the embodiment.

Further, in this embodiment, step S40 includes:

Step S41, perform an integral operation on the high-order accumulated zero-sequence currents of all feeders and reconstruct the waveform to obtain the integral value of the reconstructed waveform;

Step S42, calculate whether the ratio of the high-order accumulated reconstructed waveform integral value of any feeder to the high-order accumulated reconstructed waveform integral value of other feeders is greater than the set threshold;

Step S43, if it is greater than 1, determine that the feeder is a faulty feeder;

In the formula: for feeder The integrated value of the waveform after high-order accumulation, for feeder The integrated value of the waveform after high-order accumulation, and For any feeder in the distribution network, there are feeder line, is the integral ratio threshold, which is generally taken as 1.5. If the above formula is satisfied, then the The feeder is a faulty feeder.

Step S44, if the ratio is less than the set threshold, determine whether the The feeders are sound feeders.

Optionally, in this embodiment, the line selection criterion is formed by using the integral value of the high-order accumulated waveform of the faulty line and the integral value of the high-order accumulated waveform of the healthy feeder.

It should be noted that in order to ensure the accuracy and stability of the data, high-precision voltage sensors and current sensors should be selected, and the data should be reasonably filtered and corrected. In addition, the selection of the preset period should be adjusted according to the specific situation to fully ensure the integrity and accuracy of the data.

For example, let the bus zero sequence voltage be , the voltage threshold is ,in, Generally take 0.15, Indicates the rated voltage of the busbar.

like more than the , the fault line selection device starts immediately and records the zero-sequence current of one cycle after the fault occurs.

It should be noted that more details and special circumstances need to be considered in practical applications. For example, issues such as noise filtering, sampling frequency, and data accuracy also need to be considered.

In this embodiment, when the instantaneous value of the bus zero-sequence voltage is greater than the preset voltage threshold and it is initially determined that a fault occurs in the distribution network, the fault recording line selection device is started to perform the waveform high-voltage selection method based on the waveform high as described in the previous embodiment. The relevant steps in the distribution network fault line selection method based on sub-accumulation reconstruction can be combined with the aforementioned distribution network fault line selection method based on waveform high-order accumulation reconstruction to achieve accurate line selection.

In addition, those of ordinary skill in the art can understand that all or part of the processes in the methods of implementing the embodiments can be completed by driving relevant hardware through computer programs. The computer program includes program instructions, and the computer program can be stored in a storage medium, and the storage medium is a computer-readable storage medium. The program instructions are executed by at least one processor in the fault line selection system of the distribution network to implement the process steps of the embodiments of the above method.

Therefore, the present invention also provides a computer-readable storage medium. The computer-readable storage medium stores a fault line selection program of the distribution network. When the fault line selection program of the distribution network is executed by the processor, the above implementation is implemented. Each step of the distribution network fault line selection method based on high-order accumulation and reconstruction of waveforms described in the example.

Wherein, the computer-readable storage medium can be a USB flash drive, a mobile hard disk, a read-only memory (Read-Only Memory, ROM), a magnetic disk or an optical disk, and other computer-readable storage media that can store program codes.

It should be noted that since the storage medium provided by the embodiment of the present application is the storage medium used to implement the method of the embodiment of the present application, based on the method introduced by the embodiment of the present application, those skilled in the art can understand the storage medium. The specific structure and deformation will not be described again here. All storage media used in the methods of the embodiments of this application fall within the scope of protection of this application.

Those skilled in the art will appreciate that embodiments of the present invention may be provided as methods, systems or computer program products. Thus, the invention may take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the invention may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) having computer-usable program code embodied therein.

The present invention is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each process and/or block in the flowchart illustrations and/or block diagrams, and combinations of processes and/or blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing device to produce a machine, such that the instructions executed by the processor of the computer or other programmable data processing device produce a use A device for realizing the functions specified in a process or processes in a flowchart and/or a block or blocks in a block diagram.

These computer program instructions may also be stored in a computer-readable memory that causes a computer or other programmable data processing apparatus to operate in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including the instruction means, the instructions The device implements the functions specified in a process or processes in the flowchart and/or in a block or blocks in the block diagram.

These computer program instructions may also be loaded onto a computer or other programmable data processing device, causing a series of operating steps to be performed on the computer or other programmable device to produce computer-implemented processing, thereby executing on the computer or other programmable device. Instructions provide steps for implementing the functions specified in a process or processes of a flowchart diagram and/or a block or blocks of a block diagram.

It should be noted that in the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. The word "comprising" does not exclude the presence of elements or steps other than those listed in a claim. The word "a" or "an" preceding a component does not exclude the presence of a plurality of such components. The invention may be implemented by means of hardware comprising several different components and by means of a suitably programmed computer. In the element claim enumerating several means, several of these means may be embodied by the same item of hardware. The use of the words first, second, third, etc. does not indicate any order. These words can be interpreted as names.

Although the preferred embodiments of the present invention have been described, those skilled in the art will be able to make additional changes and modifications to these embodiments once the basic inventive concepts are apparent. Therefore, it is intended that the appended claims be construed to include the preferred embodiments and all changes and modifications that fall within the scope of the invention.

Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the invention. In this way, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and equivalent technologies, the present invention is also intended to include these modifications and variations.

Claims (10)

1. The power distribution network fault line selection method based on waveform high-order accumulation reconstruction is characterized by comprising the following steps of:

acquiring the zero sequence voltage of a bus in a power distribution network and the actual measurement zero sequence current of each feeder;

constructing a zero sequence current higher accumulated waveform corresponding to each feeder line;

calculating a waveform integral value after reconstruction of each feeder line according to the high-order accumulated waveform of the zero sequence current;

and determining fault feeder lines in the feeder lines according to the waveform curve integral values of the high-order accumulation of the zero-sequence currents.

2. The method for fault line selection of the power distribution network based on waveform high-order accumulation reconstruction according to claim 1, wherein the step of obtaining the zero sequence voltage of the bus and the actual measured zero sequence current of each feeder line in the power distribution network comprises the following steps:

measuring and recording the zero sequence voltage of a power distribution network bus and the zero sequence current of each feeder line in real time by using a voltage transformer and a current transformer;

and when the instantaneous value of the bus zero sequence voltage is larger than a preset voltage threshold value, sending an electric signal to the fault wave recording line selection device so as to start the fault wave recording line selection device.

3. The power distribution network fault line selection method based on waveform high-order accumulation reconstruction as claimed in claim 1, wherein the step of constructing the zero-sequence current high-order accumulation waveform corresponding to each feeder line comprises the following steps:

cubic operation is carried out on the zero sequence current amounts corresponding to all feeder lines in the power distribution network;

the method comprises the steps of performing cube operation on five sampling points of zero sequence current, performing enhanced accumulation, circularly accumulating until the end, obtaining a group of new zero sequence current sequences, and obtaining the high-order accumulated transformation feeder zero sequence current with enhanced amplitude and unchanged polarity, wherein the calculation method comprises the following steps:

；

wherein: set zero sequence current sharingSampling points->Is->,/>Is->Zero sequence current of the feeder line;

and drawing a zero sequence current high-order accumulation reconstruction oscillogram according to the calculated value of the high-order accumulation.

4. The power distribution network fault line selection method based on waveform high-order accumulation reconstruction according to claim 1, wherein the step of calculating waveform integral values after each feeder line reconstruction according to the zero-sequence current high-order accumulation waveform comprises:

integrating the zero sequence current higher-order accumulated waveform to obtain an integral value of the zero sequence current higher-order accumulated waveform;

；

wherein:reconstructing the waveform for higher order accumulation, +.>For the total sampling point, +.>Is a feeder.

5. The method for fault line selection of a power distribution network based on waveform high-order accumulation reconstruction according to claim 1, wherein the step of determining the faulty feeder line in each feeder line according to the waveform curve integral value of the zero-sequence current high-order accumulation comprises:

integrating the high-order accumulation reconstruction waveforms of the zero sequence currents of all the feeder lines to obtain an integral value of the reconstruction waveforms;

calculating whether the ratio of the high-order accumulated and reconstructed waveform integral value of any feeder line to the high-order accumulated and reconstructed waveform integral values of other feeder lines is larger than a set threshold value;

if the feeder line is larger than the fault feeder line, judging the feeder line as the fault feeder line;

；

wherein:for feed line->Waveform integral value after high-order accumulation, +.>For feed line->Waveform integral value after high-order accumulation, +.>And->For any feeder line in the distribution network, there is +.>A feeder line(s)>The ratio threshold value for the integral is generally 1.5, satisfying the above formula, the +.>The feeder lines are fault feeder lines;

if the ratio is smaller than the set threshold value, thenJudgment of the firstThe feeder lines are sound feeder lines.

6. The utility model provides a distribution network fault line selection system based on waveform high-order accumulation reconstruction which characterized in that, the fault line selection system of distribution network includes:

the data acquisition module is used for acquiring zero sequence voltage of a bus and zero sequence current of each feeder line in the power distribution network;

the numerical calculation module is used for completing the high-order accumulation calculation of waveforms according to the zero sequence current of each practically adopted feeder line by taking the cube and accumulating every five sampling points as a data point; calculating an integral value after the waveform is accumulated for each feeder line in a high order, calculating the ratio between any feeder lines, and comparing the ratio with a set threshold value;

and the logic judgment module is used for determining the fault feeder line according to the integral value ratio of any feeder line after reconstruction.

7. The power distribution network fault line selection system based on waveform high-order accumulation reconstruction as claimed in claim 6, wherein the data acquisition module comprises:

the data acquisition unit is used for acquiring the zero sequence voltage of the bus and the zero sequence current of each feeder line in real time;

and the analog-to-digital conversion unit is used for converting the acquired instantaneous values of the bus zero sequence voltage signal and the zero sequence current signal into digital values of digital quantity signals.

8. The power distribution network fault line selection system based on waveform high-order accumulation reconstruction according to claim 6, wherein the numerical calculation module further comprises:

starting a calculation unit: the line selecting device is used for starting the line selecting device when the acquired instantaneous value of the bus zero sequence voltage is larger than a preset voltage threshold value;

a high-order accumulation calculation unit: the method is used for realizing waveform high-order accumulation reconstruction;

an integral operation calculation unit: the method comprises the steps of calculating integral values of high-order accumulation reconstruction waveforms of all feeder lines;

an integral ratio calculating unit: for calculating the ratio of any feeder integral value to other feeder integral values.

9. The power distribution network fault line selection system based on waveform high-order accumulation reconstruction as claimed in claim 6, wherein the logic determination module further comprises:

the bus zero sequence voltage judging unit is used for determining whether the instantaneous value of the bus zero sequence voltage is larger than a preset voltage threshold value;

if yes, starting a higher-order accumulation calculation unit, an integration calculation unit and an integration ratio calculation unit;

the fault line selection judging unit is used for judging whether the ratio of the high-order accumulated and reconstructed waveform integral value of any feeder to the high-order accumulated and reconstructed waveform integral values of other feeders is larger than a set threshold value;

if the target feeder line is larger than the fault feeder line, judging the target feeder line to be the fault feeder line; if the target feeder line is smaller than the target feeder line, judging that the target feeder line is a sound feeder line.

10. A computer readable storage medium, wherein a power distribution network fault line selection program based on waveform high-order accumulation reconstruction is stored on the computer readable storage medium, and the power distribution network fault line selection program based on waveform high-order accumulation reconstruction realizes the steps of the power distribution network fault line selection method based on waveform high-order accumulation reconstruction according to any one of claims 1 to 5 when the power distribution network fault line selection program based on waveform high-order accumulation reconstruction is executed by a processor.