CN117686843A - Power distribution network fault line selection method and system based on waveform high-order accumulation reconstruction - Google Patents
Power distribution network fault line selection method and system based on waveform high-order accumulation reconstruction Download PDFInfo
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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
Technical Field
The invention relates to the technical field of relay protection of power systems, in particular to a power distribution network fault line selection method and system based on waveform high-order accumulation reconstruction and a readable storage medium.
Background
The power distribution network is an important part for connecting the power grid with users, the running stability and the running safety of the power distribution network are closely related to the life of people, and the power distribution network plays an important role in promoting the development of society and the development of economy. In China, the power distribution network generally adopts a working mode that a neutral point is grounded through an arc suppression coil or the neutral point is grounded through a small resistor, and faults are of various types, wherein single-phase grounding faults account for more than 90% of all accidents in the power distribution network. When a single-phase earth fault occurs in the system, the earth current is small, the number of feeder lines is large, and the fault characteristics are sometimes not obvious, so that great difficulty is brought to fault detection, and therefore, a single-phase earth 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 a power grid, it is particularly important to research a high-efficiency, accurate and reliable single-phase earth fault line selection method.
In the related technical scheme of the power distribution network, a neutral point of the power distribution network is generally grounded in a non-grounding or resonant grounding mode, and when a single-phase grounding fault occurs, the current flowing through the fault point is small, meanwhile, the symmetry of the system is not influenced, and the power distribution network can be operated for a period of time with the fault, so that the power distribution network is called a small-current grounding power distribution network. The small-current grounding power distribution network has the main advantages that the current flowing into the ground is small, and the protection action can not be caused for some disturbing transient faults, so that the power supply reliability is effectively improved.
However, the inventors have found that this grounding approach has the following disadvantages when they conceived and implemented the present solution: when a single-phase earth fault occurs in the power distribution network in a small-current grounding mode, the fault characteristics are not obvious, and accurate line selection is difficult to realize. The invention takes the ratio of the zero sequence current high-order accumulation reconstruction waveform integral value of each feeder line in the power distribution network as a criterion, can judge whether the feeder line is a fault line or a sound line, and can highlight the fault characteristic of the zero sequence current by utilizing the high-order accumulation waveform processing; meanwhile, the area of the reconstructed waveform is obtained by integral, the distortion characteristic of the fault zero sequence current waveform can be more accurately drawn, the weak change is amplified, and the area ratio of the fault line to the sound line after reconstruction is used as the basis of fault line selection.
Disclosure of Invention
The invention mainly aims to provide a power distribution network fault line selection method based on waveform high-order accumulation reconstruction, and aims to solve the problem of how to improve the accuracy of power distribution network line selection.
In order to achieve the above purpose, the invention provides a power distribution network fault line selection method based on waveform high-order accumulation reconstruction, which 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.
Optionally, the step of obtaining the zero sequence voltage of the bus in the power distribution network and the measured zero sequence current of each feeder line includes:
the zero sequence voltage of the bus of the distribution network and the zero sequence current of each feeder line in fault are measured and recorded in real time by using a voltage transformer (PT) and a Current Transformer (CT).
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.
Optionally, the step of constructing a higher-order accumulating waveform of the zero-sequence current corresponding to each feeder line includes:
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 sharingA number of sampling points are used to sample the sample,is that,Is the firstZero sequence current of feeder.
And drawing a zero sequence current high-order accumulation reconstruction oscillogram according to the calculated value of the high-order accumulation.
Optionally, the step of calculating the waveform integral value after each feeder line is reconstructed according to the waveform of the zero sequence current higher-order accumulation comprises the following steps:
integrating the zero sequence current high-order accumulated waveform, and calculating to obtain an integral value of the zero sequence current high-order accumulated waveform;
wherein:for the higher order accumulation of the reconstructed waveforms,as a result of the total sampling point,is a feeder.
Optionally, the step of determining the faulty feeder line in each feeder line according to the waveform curve integral value of the zero sequence current higher-order summation 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:is a feeder lineThe waveform integration value after the high-order accumulation is performed,is a feeder lineThe waveform integration value after the high-order accumulation is performed,andfor any feeder in the distribution network, there isA strip of feed lines is arranged on the feed line,the integral ratio threshold is 1.5, the above formula is satisfiedThe feeder lines are fault feeder lines.
If the ratio is smaller than the set threshold value, judging the firstThe feeder lines are sound feeder lines.
In addition, in order to achieve the above purpose, the present invention further provides a fault line selection system for a power distribution network based on waveform high-order accumulation reconstruction, where the fault line selection system for the power 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; and calculating an integral value after the waveform is accumulated higher by each feeder line, calculating the ratio between any feeder lines, and comparing the calculated value 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.
Optionally, the data acquisition module includes:
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.
Optionally, the numerical calculation module further includes:
a signal calculation unit: the method comprises the steps of constructing a starting signal when an instantaneous value of the collected bus zero sequence voltage is larger than a preset voltage threshold value;
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.
Optionally, the logic determination module further includes:
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.
In addition, in order to achieve the above object, the present invention further provides a computer readable storage medium, where a fault line selection program of a power distribution network is stored, where the fault line selection program of the power distribution network, when executed by a processor, implements the steps of the power distribution network fault line selection method based on waveform high-order accumulation reconstruction as described above.
The embodiment of the invention provides a power distribution network fault line selection method, a system and a computer readable storage medium based on waveform high-order accumulation reconstruction, which are oriented to fault line selection of a power distribution network grounding mode (grounding through an arc suppression coil, grounding through a small resistor and the like), take a high-order accumulation zero sequence current waveform integral value of each feeder line in the power distribution network as a criterion, and the high-order accumulation can not only enhance amplitude, but also has number keeping property; by using the zero sequence current as a basis, the method has the advantages of high fault sensitivity and high speed, fewer sensors are needed than normal three-phase sensors, global change can be reflected by integral operation compared with amplitude, and the fault line selection is judged more accurately.
Drawings
Fig. 1 is a schematic diagram of a fault line selection system of a power distribution network according to an embodiment of the present invention;
FIG. 2 is a model of an embodiment built based on PSCAD;
FIG. 3 is a schematic flow chart of a power distribution network fault line selection method based on waveform high-order accumulation reconstruction;
fig. 4 is a zero sequence current waveform diagram of a normal line in a power distribution network;
FIG. 5 is a zero sequence current waveform diagram of a faulty line in a power distribution network;
fig. 6 is a waveform diagram of high-order accumulation reconstruction of zero-sequence currents of all feeder lines.
The achievement of the objects, functional features and advantages of the present invention will be further described with reference to the accompanying drawings, in conjunction with the embodiments.
Detailed Description
In order to better understand the above technical solution, exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be embodied in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.
As an implementation scheme, fig. 1 is a schematic architecture diagram of a fault line selection system of a power distribution network according to an embodiment of the present invention.
As shown in fig. 1, the system includes a data acquisition module 101, a numerical calculation module 102, and a logic determination module 103. The data acquisition module 101 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 102 firstly takes cubes and then accumulates every five sampling points as a data point according to the real zero sequence current of each feeder line to finish the high-order accumulation calculation of waveforms; 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; the logic judging module 103 is configured to determine a faulty feeder according to the ratio of the integrated values after the reconstruction of any feeder. Wherein:
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 for acquiring the zero sequence voltage of the bus and the zero sequence current of each feeder line in real time; the analog-to-digital conversion unit 1012 is used for converting the instantaneous values of the collected bus zero sequence voltage signal and zero sequence current signal into digital values of digital quantity signals.
The numerical calculation module 102 may include a start calculation unit 1021, a higher order accumulation calculation unit 1022, an integration calculation unit 1023, and an integration ratio calculation unit 1024. The starting calculation unit 1021 is used for starting the line selection device when the acquired instantaneous value of the bus zero sequence voltage is greater than a preset voltage threshold value; the higher-order accumulation calculation unit 1022 is used for realizing waveform higher-order accumulation reconstruction; the integral operation calculation unit 1023 is used for calculating integral values of the higher-order accumulation reconstruction waveforms of the feeder lines; the integral ratio calculating unit 1024 is configured to calculate a ratio of any feeder integral value to other feeder integral values.
The logic determination module 103 may include a bus zero sequence voltage determination unit 1031 and a fault line selection determination unit 1032. The bus zero sequence voltage judging unit 1031 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 1032 is configured to judge whether a ratio of the higher-order accumulated and reconstructed waveform integral value of any feeder line to the higher-order accumulated and reconstructed waveform integral values of other feeder lines is greater 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. .
In addition, the fault line selection system of the power distribution network shown in fig. 1 further includes a memory 104 and a processor 105, where the memory 104 may be a high-speed RAM memory or a stable memory (non-volatile memory), such as a disk memory. The memory 104 is used for storing a fault line selection program of the distribution network as a computer readable storage medium, and the processor 105 may be used for calling the fault line selection program of the distribution network stored in the memory 104 and performing the following operations:
acquiring zero sequence voltage of a bus in a power distribution network and acquiring actual measurement zero sequence current of each feeder line;
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.
In an embodiment, when the processor 105 invokes the fault line selection program of the power distribution network stored in the memory 104, the following operations are performed:
the zero sequence voltage of the bus of the distribution network and the zero sequence current of each feeder line in fault are measured and recorded in real time by using a voltage transformer (PT) and a Current Transformer (CT).
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.
In an embodiment, when the processor 105 invokes the fault line selection program of the power distribution network stored in the memory 104, the following operations are performed:
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 sharingA number of sampling points are used to sample the sample,is that,Is the firstZero sequence current of feeder.
And drawing a zero sequence current high-order accumulation reconstruction oscillogram according to the calculated value of the high-order accumulation.
In an embodiment, when the processor 105 invokes the fault line selection program of the power distribution network stored in the memory 104, the following operations are performed:
integrating the zero sequence current high-order accumulated waveform, and calculating to obtain an integral value of the zero sequence current high-order accumulated waveform;
wherein:for the higher order accumulation of the reconstructed waveforms,as a result of the total sampling point,is a feeder.
In an embodiment, when the processor 105 invokes the fault line selection program of the power distribution network stored in the memory 104, the following operations are performed:
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:is a feeder lineThe waveform integration value after the high-order accumulation is performed,is a feeder lineThe waveform integration value after the high-order accumulation is performed,andfor any feeder in the distribution network, there isA strip of feed lines is arranged on the feed line,the integral ratio threshold is 1.5, the above formula is satisfiedThe feeder lines are fault feeder lines.
If the ratio is smaller than the set threshold value, judging the firstThe feeder lines are sound feeder lines.
Furthermore, it will be appreciated by those skilled in the art that the architecture of the fault line selection system of the power distribution network shown in fig. 1 does not constitute a limitation of the fault line selection system of the power distribution network, and may include more or fewer components than shown, or may combine certain components, or a different arrangement of components.
The invention provides a hardware architecture of a power distribution network fault line selection system based on a power system relay protection technology, and provides an embodiment of a power distribution network fault line selection method based on waveform high-order accumulation reconstruction.
Referring to fig. 2, the invention builds an embodiment distribution line model in PSCAD, wherein 4 feeder lines are provided, L1 and L4 are overhead lines, L2 and L3 are cable lines, the sampling frequency is 10kHz, and a single-phase metallic ground fault is arranged in the L1 section overhead line.
Referring to fig. 3, fig. 3 is a flowchart of a specific implementation of a fault line selection method and system for a power distribution network based on waveform high-order accumulation reconstruction provided by the invention.
Step S10, acquiring zero sequence voltage of a bus in a power distribution network and acquiring actual measurement zero sequence current of each feeder line;
FIG. 4 is a zero sequence current waveform diagram of a faulty line in a power distribution network; FIG. 5 is a waveform diagram of zero sequence current of a normal line in a power distribution network;
it should be noted that, in the embodiment, for the small-current grounding system of the power distribution network, only the zero-sequence current transformer is needed, and the cost is lower than that of the three-phase current transformer.
S20, constructing a zero sequence current higher-order accumulation waveform corresponding to each feeder line;
in this embodiment, after the actual measurement of the zero sequence current of the feeder line is obtained, the cubic operation of the zero sequence current waveform is performed first, so that the fault abrupt change is more obvious, and then the accumulation operation of every five sampling points is performed to complete the waveform reconstruction. The zero sequence current waveform of the fault feeder is amplified, so that the fault characteristics are more obvious and better distinguished from the sound feeder.
Step S30, calculating a waveform integral value after reconstruction of each feeder line according to the zero sequence current high-order accumulated waveforms;
calculating a high-order accumulated waveform integral value of the zero-sequence current corresponding to each feeder line, wherein the high-order accumulated waveform integral value of the zero-sequence current is represented as a numerical value obtained by integrating the reconstructed zero-sequence current waveform of the feeder line and is generally used for representing the total quantity of fault characteristics of the feeder line in a certain time period.
Step S40, determining fault feeder lines in the feeder lines according to the waveform curve integral values of the zero sequence current high-order accumulation;
in the technical scheme provided by the embodiment, the high-order accumulated waveform integral value of the zero sequence current of each feeder line in the power distribution network is used as a criterion to judge whether the feeder line is a fault line, and because only the zero sequence current of the line needs to be measured, the required data information amount is less, and the required sensing equipment is less than the required sensing equipment for measuring three phases, the difference between the fault feeder line and the normal feeder line can be highlighted through the high-order sum accumulation, so that accurate line selection can be realized under the condition that the fault grounding current of the power distribution network in a small-current grounding mode is small.
Further, in this embodiment, the step S20 includes:
s21, performing cubic operation on zero sequence current amounts corresponding to all feeder lines in the power distribution network;
step S22, the five sampling points of the zero sequence current after cubic operation are enhanced and accumulated, and the zero sequence current is circularly accumulated until the end, so as to obtain a group of new zero sequence current sequences, and the high order accumulated transformation feeder zero sequence current with enhanced amplitude and unchanged polarity is obtained, and the calculation method is as follows:
wherein: set zero sequence current sharingA number of sampling points are used to sample the sample,is that,Is the firstZero sequence current of feeder.
And S23, drawing a high-order accumulation reconstruction waveform chart of the zero-sequence current according to the calculated value of the high-order accumulation.
Further, in this embodiment, the step S30 includes:
step S31, integrating the zero sequence current higher-order accumulated waveform, and calculating to obtain an integral value of the zero sequence current higher-order accumulated waveform;
wherein:for the higher order accumulation of the reconstructed waveforms,as a result of the total sampling point,is a feeder.
Fig. 6 is a waveform diagram of high-order accumulation reconstruction of zero-sequence currents of each feeder line according to an embodiment.
Further, in this embodiment, the step S40 includes:
step S41, integrating the high-order accumulation reconstruction waveforms of the zero sequence currents of all feeder lines to obtain an integral value of the reconstruction waveforms;
step S42, calculating whether the ratio of the high-order accumulation reconstruction waveform integral value of any feeder line to the high-order accumulation reconstruction waveform integral values of other feeder lines is larger than a set threshold value;
step S43, if the feeder is larger than the fault feeder, judging the feeder to be the fault feeder;
wherein:is a feeder lineThe waveform integration value after the high-order accumulation is performed,is a feeder lineThe waveform integration value after the high-order accumulation is performed,andfor any of the distribution networksA wire withA strip of feed lines is arranged on the feed line,the integral ratio threshold is 1.5, the above formula is satisfiedThe feeder lines are fault feeder lines.
Step S44, if the ratio is smaller than the set threshold, judging the firstThe feeder lines are sound feeder lines.
Optionally, in this embodiment, the line selection criterion is formed by using the integral value of the fault line higher-order accumulated waveform and the magnitude value of the integral value of the sound feeder higher-order accumulated waveform.
It should be noted that, in order to ensure accuracy and stability of data, a high-precision voltage sensor and a high-precision current sensor should be selected, and the data is reasonably filtered and corrected. In addition, the selection of the preset period should be adjusted according to specific conditions so as to fully ensure the integrity and accuracy of the data.
Illustratively, let the bus zero sequence voltage beA voltage threshold ofWherein, the method comprises the steps of, wherein,generally, the amount of the catalyst is 0.15,indicating the bus voltage rating.
If it isGreater thanAnd the fault line selection device is started immediately, and the zero sequence current of a cycle after the fault occurs is recorded.
It should be noted that in practical application, more details and special cases need to be considered. For example, problems in noise filtering, sampling frequency, and data accuracy are also required to be considered.
In this embodiment, when the instantaneous value of the zero sequence voltage of the bus is greater than the preset voltage threshold, and it is primarily determined that a fault occurs in the power distribution network, the fault recording line selection device is started to execute the relevant steps in the power distribution network fault line selection method based on waveform high-order accumulation reconstruction described in the foregoing embodiment, and the accurate line selection can be achieved by combining with the foregoing power distribution network fault line selection method based on waveform high-order accumulation reconstruction.
Furthermore, it will be appreciated by those of ordinary skill in the art that all or part of the flow in a method to implement an embodiment may be accomplished by computer program driven related hardware. The computer program comprises program instructions, and the computer program may be stored in a storage medium, which is a computer readable storage medium. The program instructions are executed by at least one processor in a fault line selection system of the power distribution network to implement the flow steps of the embodiments of the method described above.
Therefore, the invention also provides a computer readable storage medium, wherein the computer readable storage medium stores a fault line selection program of the power distribution network, and the fault line selection program of the power distribution network realizes the steps of the power distribution network fault line selection method based on waveform high-order accumulation reconstruction according to the embodiment when being executed by a processor.
The computer readable storage medium may be a usb disk, a removable hard disk, a Read-Only Memory (ROM), a magnetic disk, or an optical disk, etc. which may store the program code.
It should be noted that, because the storage medium provided in the embodiments of the present application is a storage medium used to implement the method in the embodiments of the present application, based on the method described in the embodiments of the present application, a person skilled in the art can understand the specific structure and the modification of the storage medium, and therefore, the description thereof is omitted herein. All storage media used in the methods of the embodiments of the present application are within the scope of protection intended in the present application.
It will be appreciated by those skilled in the art that embodiments of the present invention may be provided as a method, system, or computer program product. Accordingly, the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present 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, and the like) 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 flow and/or block of the flowchart illustrations and/or block diagrams, and combinations of flows 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 apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
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 not listed in a claim. The word "a" or "an" preceding an element does not exclude the presence of a plurality of such elements. The invention may be implemented by means of hardware comprising several distinct elements, and by means of a suitably programmed computer. In the unit claims enumerating several means, several of these means may be embodied by one and the same item of hardware. The use of the words first, second, third, etc. do not denote any order. These words may be interpreted as names.
While preferred embodiments of the present invention have been described, additional variations and modifications in those embodiments may occur to those skilled in the art once they learn of the basic inventive concepts. It is therefore intended that the following claims be interpreted as including the preferred embodiments and all such alterations and modifications as fall within the scope of the invention.
It will be apparent to those skilled in the art that various modifications and variations can be made to the present invention without departing from the spirit or scope of the invention. Thus, it is intended that the present invention also include such modifications and alterations insofar as they come within the scope of the appended claims or the equivalents thereof.
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.
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