CN115656702A - Power distribution network single-phase earth fault positioning method and system based on edge calculation - Google Patents
Power distribution network single-phase earth fault positioning method and system based on edge calculation Download PDFInfo
- Publication number
- CN115656702A CN115656702A CN202211107226.2A CN202211107226A CN115656702A CN 115656702 A CN115656702 A CN 115656702A CN 202211107226 A CN202211107226 A CN 202211107226A CN 115656702 A CN115656702 A CN 115656702A
- Authority
- CN
- China
- Prior art keywords
- fault
- distribution network
- power distribution
- current
- phase
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Images
Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y04—INFORMATION OR COMMUNICATION TECHNOLOGIES HAVING AN IMPACT ON OTHER TECHNOLOGY AREAS
- Y04S—SYSTEMS INTEGRATING TECHNOLOGIES RELATED TO POWER NETWORK OPERATION, COMMUNICATION OR INFORMATION TECHNOLOGIES FOR IMPROVING THE ELECTRICAL POWER GENERATION, TRANSMISSION, DISTRIBUTION, MANAGEMENT OR USAGE, i.e. SMART GRIDS
- Y04S10/00—Systems supporting electrical power generation, transmission or distribution
- Y04S10/50—Systems or methods supporting the power network operation or management, involving a certain degree of interaction with the load-side end user applications
- Y04S10/52—Outage or fault management, e.g. fault detection or location
Landscapes
- Locating Faults (AREA)
Abstract
The invention discloses a method and a system for positioning a single-phase earth fault of a power distribution network based on edge calculation, wherein a fault indicator installed on a line is used for continuously acquiring a three-phase current of the line and synthesizing a zero-sequence current; comparing the zero sequence current amplitude value with a set threshold value, and pre-judging a line section with a power distribution network fault; starting a fault type sensing algorithm aiming at a line section which is predicted to have a power distribution network fault, distinguishing the fault type in a self-adaptive mode, and selecting a transient process algorithm or a steady process algorithm corresponding to the distinguished fault type to calculate the obtained line three-phase current; and (4) positioning and judging a fault path or a non-fault path of the line section which is pre-judged to have the power distribution network fault by combining the transient current characteristics of the phase current obtained by the transient process algorithm and the steady-state current characteristics obtained by the steady-state process algorithm. The invention adopts the fault type sensing algorithm, self-adaptively distinguishes the fault type, can judge the fault position on site and reduces the dependence of the algorithm on communication.
Description
Technical Field
The invention relates to the field of single-phase earth faults in a power distribution network, in particular to a power distribution network single-phase earth fault positioning method and system based on edge calculation.
Background
The safe and stable operation of the distribution automation equipment is an important guarantee for the performance of the distribution automation system, and the distribution automation equipment comprises a feeder terminal FTU, a station terminal DTU, a fault indicator, a primary and secondary fusion complete switch and the like. In particular, the fault indicators are relatively low in price and simple and flexible to install, so that the fault indicators are distributed in a large number in a power distribution network and are wide in points. However, the difference between the operating environment and the state of the fault indicator is large, so that the fault current is small after a single-phase earth fault occurs, and the action accuracy of the fault indicator is not high. Therefore, it is of great significance to research key technologies to improve the processing capacity of the fault indicator single-phase earth fault.
The traditional design scheme of the fault indicator is that a plurality of indicator terminals are dispersedly installed on a line, each terminal comprises three fault indicators and a concentrator, and the terminals upload data to a main station. The fault indicator has two schemes, the first scheme is as follows: each terminal compares the measured value with the fixed value in real time, local indication is carried out after the measured value is found to be larger than the fixed value, remote communication quantity is uploaded at the same time, and the master station obtains action information of each terminal to carry out fault location. This approach is obviously not suitable for single-phase earth faults, because when a single-phase earth fault occurs on a line, zero-sequence currents are generated on each line and each branch (note that the fault path is not), and the fixed value is difficult to set. The second scheme is as follows: the scheme is theoretically the best, but the effect is often poor due to the restriction of communication, the main station fails to receive accurate data to cause positioning failure due to the failure or delay of a communication system, a complex positioning algorithm is concentrated on the main station, the load capacity of the main station is increased, and the real-time processing capacity of the main station is influenced.
Disclosure of Invention
In order to utilize the existing system to collect local information to complete the single-phase earth fault judgment of the power distribution network and meet the requirement that the single-phase earth fault judgment and processing of the power distribution network can be still rapidly and accurately completed when a zero sequence voltage transformer and a zero sequence current transformer are not installed and the communication is not good or the communication fails, the invention provides the single-phase earth fault positioning method and the single-phase earth fault positioning system of the power distribution network based on edge calculation, and the power supply reliability, the safety and the economy of the power distribution network are improved.
The adopted technical scheme is as follows:
on one hand, the invention provides a power distribution network single-phase earth fault positioning method based on edge calculation, which comprises the following steps of 1, continuously acquiring three-phase current of a line by using a fault indicator installed on the line, and synthesizing zero-sequence current;
step 3, starting a fault type perception algorithm aiming at a line section with a power distribution network fault in advance, identifying the fault type in a self-adaptive mode, and selecting a transient process algorithm or a steady process algorithm corresponding to the identified fault type to calculate the obtained line three-phase current;
and 4, combining the transient current characteristics of the phase currents obtained by the transient process algorithm and the steady-state current characteristics obtained by the steady-state process algorithm, and making a positioning judgment on a fault path or a non-fault path for the line section which is pre-judged to have the power distribution network fault.
And further, the method also comprises a step 5 of uploading the positioning judgment result obtained in the step 4 and the acquired data to a master station for centralized processing by the fault indicator through a network.
In the step 2, when the zero sequence current amplitude on the obtained line is greater than the set threshold value, the power distribution network fault is pre-determined, otherwise, the fault indicator continuously monitors the zero sequence current amplitude.
Starting a fault type sensing algorithm in the step 3, identifying the fault type in a self-adaptive manner, and selecting a transient process algorithm or a steady process algorithm corresponding to the identified fault type; the method comprises the following specific steps:
step 3.1, phase currents in 5 periods before and after the moment of starting the fault type sensing algorithm are obtained, and zero-sequence current signals are synthesized;
3.2, filtering the synthesized zero-sequence current signal by using improved S transformation to obtain a power distribution network fault line section corresponding to the accurate fault occurrence moment and a high-frequency component and a fundamental frequency component of the zero-sequence current in a period after the fault occurrence;
3.3, establishing a self-adaptive sensing criterion after obtaining the amplitude by utilizing the high-frequency component and the fundamental frequency component, and respectively judging the fault type of a neutral point through an arc suppression coil ground fault or a resistance ground fault in a fault line section of the power distribution network;
step 3.4, when the type of the grounding fault of the neutral point passing through the arc suppression coil is judged, load current of the obtained three-phase current is filtered, and then a steady-state process algorithm is adopted for calculation; and when the type of the resistance earth fault is judged, the obtained three-phase current is subjected to load current filtering, and then transient process algorithm calculation is adopted.
Further, the adaptive sensing criterion established in said step 3.3 is: k is A ·A 0 >A, when the self-adaptive sensing criterion is met, judging that a power distribution network fault line section has a resistance earth fault, otherwise, judging that a power distribution network fault line section has a neutral point earth fault through an arc suppression coil;
wherein: a is the amplitude of the high frequency component, A 0 Is the amplitude of the fundamental frequency component;
K A the value of the adaptive coefficient is 0.4-0.5.
In the step 4, the positioning judgment of the fault path or the non-fault path is made for the line section which is predicted to have the fault of the power distribution network by combining the steady-state current characteristics obtained by the steady-state process algorithm, and the judgment basis is as follows: the fault component of the fault phase on the fault path is larger than that of the non-fault phase, and the fault components of the non-fault phases are equal; the fault components of the three-phase currents on the non-fault paths are all the same.
In step 4, the positioning judgment of the fault path or the non-fault path is made for the line section which is pre-judged to have the power distribution network fault by combining the phase current transient current characteristics obtained by the transient process algorithm, and the judgment method is as follows:
step 4.1, setting the processed fault component signals of the fault line section of the power distribution network as follows:
y＝f(x)
wherein x is a sampling point on a fault line section of the power distribution network, and y is a current value;
step 4.2, the sampling point corresponding to the fault occurrence moment obtained by improving S conversion is x 0 Simultaneously at sampling point x 0 A plurality of calculation intervals are defined nearby for calculating the current value;
step 4.3, sampling point x at the moment of fault occurrence 0 Taking the corresponding function values as reference values, and respectively taking the absolute values of the results by taking the difference between the corresponding function values in a plurality of calculation intervals and the reference values according to the following formula:
y max ＝max{|f(x 0 +1)-f(x 0 )|,...,|f(x 0 +N)-f(x 0 )|}
wherein N is the number of the specified calculation interval, and the value is 1, 2, 3, 4 \8230;
step 4.4, find the maximum value y of the current from step 4.3 max Corresponding sampling point x max As mutation points:
x max ＝f -1 (y max )
step 4.5, comparing abrupt change direction results corresponding to three-phase currents on the same power distribution network fault line, and judging that the path is a fault path and an abrupt change direction different phase is a fault phase when two-phase current calculation results Dir are the same and the other phase current is different; and when the three-phase current calculation results Dir on the power distribution network fault line are the same, judging the path to be a non-fault path.
In another aspect, a single-phase earth fault location system of a power distribution network based on edge calculation comprises a plurality of fault indicators installed on a power distribution network line, wherein each fault indicator comprises a low-speed acquisition module, a trigger module, a high-speed data acquisition module, a memory, a data processor and a local judgment module;
the low-speed acquisition module is used for low-speed acquisition and data processing of the power distribution network line and pre-judging whether a power distribution network fault occurs or not;
the data high-speed acquisition module is used for circularly acquiring current data at a high speed through the FPGA and converting analog quantity into digital quantity;
when the low-speed acquisition module pre-judges that the power distribution network has a fault, the trigger module starts and sends out a pulse, the data high-speed acquisition module starts to acquire transient current data, and the acquired transient current data and the three-phase current data of the circuit are stored in the memory;
the data processor is internally provided with a fault type perception algorithm module which comprises a transient process algorithm or a steady-state process algorithm, wherein the transient process algorithm is used for obtaining phase current transient current characteristics, and the steady-state process algorithm is used for obtaining phase current steady-state current characteristics.
And the local judgment module is used for positioning and judging a fault path or a non-fault path of a line section which is pre-judged to have a power distribution network fault by combining the transient current characteristic and the steady-state current characteristic which are obtained by calculation of the data processor.
Furthermore, a communication module is further arranged in the fault indicator, and the data processor is used for instructing the data in the memory to be uploaded to a master station through the communication module for centralized processing.
The technical scheme of the invention has the following advantages:
A. the method adopts a fault type perception algorithm aiming at a line section with a power distribution network fault in advance, adaptively distinguishes the fault type, selects a transient process algorithm or a steady-state process algorithm corresponding to the distinguished fault type, takes the transient and steady-state current fault characteristics of phase current as criteria, can realize the local judgment of the fault position, reduces the dependence of the algorithm on communication, and can still complete the fault line selection on the site under the condition that communication signals are poor or lack of communication. The method and the device use transient and steady-state characteristics of the phase current on the line as criteria to distinguish a fault section and a non-fault section in the line, so as to solve the problem of single-phase earth fault positioning in the line and improve the power supply reliability, safety and economy of the power distribution network.
B. The method can complete the single-phase earth fault judgment of the power distribution network by utilizing the existing collectable local information in the existing system, so that the system has stronger applicability, the positioning system can meet the requirement of the system without installing a zero sequence voltage transformer and a zero sequence current transformer, and the single-phase earth fault judgment and treatment of the power distribution network can be still quickly and accurately completed when the communication is poor or fails.
C. The phase current signal in the invention is taken as a signal which is easy to be collected, the fault contains abundant fault information after the fault occurs, and the node phase current is easy to extract for fault positioning through the installation of a novel distribution network fault indicator based on edge calculation at each node in a distribution network circuit; the condition that the applicability of a fault line selection system is influenced due to the fact that a zero sequence current signal acquisition device is lacked in the system can be avoided by adopting the phase current as the judgment signal.
D. The fault indicator terminal adopted by the invention can utilize local information to judge without depending on communication, and the master station only needs to carry out simple topology on the positioning result of the fault indicator terminal without carrying out complex calculation.
Drawings
In order to more clearly illustrate the embodiments of the invention, the drawings that are required for the embodiments will be briefly described below, it being apparent that the drawings in the following description are some embodiments of the invention, and that other drawings may be derived from those drawings without inventive effort by a person skilled in the art.
Fig. 1 is a flow chart of a single-phase earth fault positioning method for a power distribution network provided by the invention;
FIG. 2 is a block diagram of a single-phase earth fault location system for a power distribution network according to the present invention;
FIG. 3 is an ATP model diagram of a neutral point arc suppression coil grounding system provided by the invention;
FIG. 4 is a diagram of a fault path current waveform provided by the present invention;
FIG. 5 is a waveform of line current downstream of a fault point provided by the present invention;
FIG. 6 is a diagram of a normal line current waveform provided by the present invention;
FIG. 7 is a waveform diagram of a fault path provided by the present invention;
FIG. 8 is a waveform of line current downstream of the fault point provided by the present invention;
fig. 9 is a diagram of a normal line current waveform provided by the present invention.
Detailed Description
The technical solutions of the present invention will be described clearly and completely with reference to the accompanying drawings, and it should be understood that the described embodiments are some, but not all embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments of the present invention without making any creative effort, shall fall within the protection scope of the present invention.
As shown in fig. 1, the invention provides a method for positioning a single-phase earth fault of a power distribution network based on edge calculation, which comprises the following steps:
and (S001) continuously acquiring the three-phase current of the line by using a fault indicator arranged on the line, and synthesizing a zero-sequence current.
[ S002 ] according to the zero-sequence current amplitude I and the set threshold I Dhr And comparing, and prejudging the line section with the power distribution network fault. And when the zero sequence current amplitude is larger than the set threshold value, judging that a fault occurs and starting a fault sensing algorithm, otherwise, continuously monitoring the zero sequence current amplitude by the fault indicator.
And (S003) starting a fault type perception algorithm aiming at the line section with the power distribution network fault in advance, adaptively distinguishing the fault type, and selecting a transient process algorithm or a steady process algorithm corresponding to the distinguished fault type.
Starting a fault type perception algorithm, adaptively distinguishing the fault type, and selecting a transient process algorithm or a steady process algorithm corresponding to the distinguished fault type; the method comprises the following specific steps:
s0031, acquiring phase currents in 5 periods before and after the moment of starting the fault type perception algorithm, and synthesizing a zero-sequence current signal;
s0032, filtering the synthesized zero-sequence current signal by using improved S transformation, and acquiring a high-frequency component and a fundamental frequency component of the power distribution network fault line section corresponding to the accurate fault occurrence moment and the zero-sequence current in a period after the fault occurrence;
s0033, establishing a self-adaptive sensing criterion after obtaining the amplitude by utilizing the high-frequency component and the fundamental frequency component, and respectively judging the fault type of a neutral point grounded fault or a resistance grounded fault through an arc suppression coil in a power distribution network fault line section;
the established adaptive perception criterion is as follows: k is A ·A 0 >A；
When the self-adaptive sensing criterion is met, judging that a resistance grounding fault occurs in the power distribution network fault line section, otherwise, judging that a neutral point grounding fault occurs in the power distribution network fault line section through an arc suppression coil;
wherein: a is the amplitude of the high frequency component, A 0 Is the amplitude of the fundamental frequency component;
K A is a self-adaptive coefficient, and the value of the self-adaptive coefficient is 0.4 to 0.5.
S0034, when the type of the grounding fault of the neutral point through the arc suppression coil is judged, the obtained phase current is subjected to load current filtering and then calculated by adopting a steady-state process algorithm; and when the type of the resistance ground fault is judged, filtering load current of the obtained phase current, and calculating by adopting a transient process algorithm.
And (S004), positioning and judging a fault path or a non-fault path of the line section with the power distribution network fault in advance by combining the transient current characteristics of the phase current obtained by the transient process algorithm and the steady-state current characteristics obtained by the steady-state process algorithm.
The method comprises the following steps of combining steady-state current characteristics obtained by a steady-state process algorithm, and performing positioning judgment on a fault path or a non-fault path on a line section which is predicted to have a fault of the power distribution network according to the judgment basis that fault components of three-phase currents of the fault path and the non-fault path are analyzed to obtain the following steps: the fault component of the fault phase on the fault path is larger than that of the non-fault phase, and the fault components of the non-fault phases are equal; the fault components of the three-phase current on the non-fault path are all the same.
Because the phase current contains harmonic waves and load current interference, a signal with high reliability cannot be obtained only by subtracting currents before and after a fault. In order to avoid the influence of the high-frequency component on the direction of the signal sudden change, the algorithm firstly utilizes improved S transformation to filter the three-phase current signals, and searches for the sudden change point of the phase current after obtaining the fundamental frequency component to determine the direction of the sudden change. The invention provides an algorithm for determining the direction of phase current sudden change, and the method is characterized in that the method comprises the following steps of:
s0041, setting the processed fault component signal of the power distribution network fault line segment as:
y＝f(x)
wherein x is a sampling point of a fault line section of the power distribution network, and y is a current value;
(S0042) a sampling point corresponding to a fault occurrence time obtained by improving S transformation is x 0 At sample point x 0 A plurality of nearby calculation intervals are regulated for calculating the current value;
(S0043) sampling point x at fault occurrence moment 0 Taking the corresponding function values as reference values, and respectively taking the absolute values of the results by taking the difference between the corresponding function values in a plurality of calculation intervals and the reference values according to the following formula:
y max ＝max{|f(x 0 +1)-f(x 0 )|,...,|f(x 0 +N)-f(x 0 )|}
where N is a specified number of calculation intervals, e.g., N is 20, and the specified calculation interval is [ x ] 0 +1，x 0 +20]。
[ S0044 ] finding the maximum value y of the current from [ S0043 ] max Corresponding sampling point x max As mutation points:
x max ＝f -1 (y max )
comparing abrupt change direction results corresponding to three-phase currents on a fault line of the same power distribution network, and when two-phase current calculation results Dir are the same and the other phase current is different, judging that the path is a fault path and the abrupt change direction different phase is a fault phase; and when the three-phase current calculation results Dir on the power distribution network fault line are the same, judging that the path is a non-fault path.
And (S005) the fault indicator uploads the positioning judgment result obtained in the step (S004) and the acquired data to the master station for centralized processing through the network.
The fault type perception algorithm adopted by the invention utilizes improved S transformation to decompose and obtain the amplitude-frequency characteristic at the fault moment, and extracts the amplitude A of the high-frequency component and the amplitude A of the fundamental frequency component 0 By setting K A ·A 0 The harmonic content in the line is lower and the steady state process is stable when the criteria are met, and a steady state algorithm can complete a fault positioning task; on the contrary, the harmonic content in the circuit is high, the neutral point ungrounded fault and the fault of the grounding through the arc suppression coil can occur, and the transient criterion is adopted for judgment because the steady criterion can not be accurately judged. Wherein, K A Can be determined according to field actual measurement data and engineering experience, and is tested by a large amount of actual data, K A The value range of 0.4-0.5 can satisfy most of conditions.
On the other hand, as shown in fig. 2, the invention also provides a power distribution network single-phase earth fault positioning system based on edge calculation, which comprises a plurality of fault indicators installed on a line, wherein each fault indicator comprises a low-speed acquisition module, a trigger module, a high-speed data acquisition module, a memory, a data processor and a local judgment module.
The low-speed acquisition module is used for low-speed acquisition and data processing and pre-judging whether the power distribution network fault occurs or not;
the data high-speed acquisition module acquires current data in a high-speed circulation mode through the FPGA, converts analog quantity into digital quantity and can be divided into an A/D high-speed conversion circuit and a high-capacity SDRAM; because the frequency of the transient current signal is higher, the frequency range is more, the lower sampling frequency can not obtain the actual waveform, the measurement precision is influenced, in order to provide accurate and effective data for short-circuit fault positioning, a 16-bit A/D high-speed conversion chip is selected for an A/D high-speed conversion circuit, and the sampling frequency is 2 multiplied by 1MHz; the data high-speed acquisition module selects 16-bit 256M DDR3-SDRAM.
When the low-speed acquisition module pre-judges that the power distribution network has a fault, the trigger module starts and sends out pulses, the data high-speed acquisition module starts to acquire transient current data and stores the acquired transient current data and the three-phase current data of the circuit into a memory, and the memory preferably adopts an SD card;
the data processor is provided with a fault type perception algorithm module which comprises a transient process algorithm or a steady-state process algorithm, wherein the transient process algorithm is used for obtaining phase current transient current characteristics, and the steady-state process algorithm is used for obtaining phase current steady-state current characteristics.
And the local judgment module is used for positioning and judging a fault path or a non-fault path of the line section which is pre-judged to have the power distribution network fault by combining the transient current characteristic and the steady-state current characteristic which are obtained by calculation of the data processor.
Of course, the invention may further include a communication module in the fault indicator, and the data processor is configured to upload the data in the instruction memory to the master station through the communication module for centralized processing, where the communication module preferably uses gigabit ethernet.
The invention utilizes physicsAnd carrying out analog simulation test on the test platform. Mainly aims at simulation verification of high-resistance grounding and arc grounding in a neutral point arc suppression coil grounding system with high positioning difficulty, and sets K A Is 0.49. The neutral point arc suppression coil grounding system model is shown in fig. 3 below, and a fault line is divided into a fault point upstream line and a fault point downstream line.
After the ground resistance is set to 2000 Ω, the failed phase is the a phase, and the three-phase current waveforms of the failed path and the non-failed path are shown in fig. 4, 5, and 6.
The waveform can be obtained, and the transient process is fuzzy and can not be judged due to the fact that the grounding resistance is large and the current transient process is greatly attenuated, the phase current has no obvious sudden change. Under the condition of grounding through high impedance, the ratio of the high-frequency component amplitude to the fundamental frequency component amplitude of the three lines is as follows: 0.0527, 0.0374 and 0.0288, therefore, the positioning method utilizes the steady-state feature to judge, and the calculation results are shown in the following table:
TABLE 1 results of the calculation of the steady-state criterion for each phase
And under the condition of high-resistance grounding, the fault perception algorithm judges by using the steady-state characteristics, the current steady-state characteristics are obvious, the variance of the fault path is displayed to be far greater than that of the non-fault path in the calculation result, the analysis of the steady-state process is verified, and the fault positioning can be correctly completed.
When the grounding point is set to be grounded through the arc, the fault phase is the C phase, and the phase current waveforms of the fault path and the non-fault path are shown in fig. 7, fig. 8 and fig. 9.
The waveform shows that the transient process is very obvious in the arc grounding process, and obvious mutation can be observed. Under the condition of arc grounding, the ratio of the high-frequency component amplitude to the fundamental frequency component amplitude of the three lines is as follows: 0.6297, 0.5941, and 0.5100, so the transient characteristics are used to determine the fault path result, and the transient result obtained by the signal after improved S transformation and the above formula is shown in the following table:
TABLE 2 transient criterion calculation results of each phase
The characteristic of large content of arc grounding harmonic enables a fault perception algorithm to select transient characteristics for judgment, the current transient characteristics are obvious, three-phase mutation directions in a fault path are different, but three-phase mutation directions in a non-fault path are the same, the analysis of the fault component current transient process is verified, and a positioning system can correctly complete fault positioning.
Nothing disclosed in this application is applicable to the prior art.
It should be understood that the above examples are only for clarity of illustration and are not intended to limit the embodiments. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. And obvious variations or modifications derived therefrom are intended to be within the scope of the present invention.
Claims (9)
1. A method for positioning single-phase earth fault of power distribution network based on edge calculation is characterized in that,
step 1, continuously acquiring three-phase current of a line by using a fault indicator installed on the line, and synthesizing zero-sequence current;
step 2, obtaining a zero sequence current amplitude value according to the zero sequence current, comparing the zero sequence current amplitude value with a set threshold value, and prejudging a line section with a power distribution network fault;
step 3, starting a fault type perception algorithm aiming at a line section with a power distribution network fault in advance, identifying the fault type in a self-adaptive mode, and selecting a transient process algorithm or a steady process algorithm corresponding to the identified fault type to calculate the obtained line three-phase current;
and 4, combining the transient current characteristics of the phase currents obtained by the transient process algorithm and the steady-state current characteristics obtained by the steady-state process algorithm, and making a positioning judgment on a fault path or a non-fault path for the line section which is pre-judged to have the power distribution network fault.
2. The method for positioning the single-phase earth fault of the power distribution network based on the edge calculation as claimed in claim 1, further comprising a step 5, wherein the fault indicator uploads the positioning judgment result obtained in the step 4 and the collected data to a master station through a network for centralized processing.
3. The power distribution network single-phase earth fault location method based on edge calculation as claimed in claim 1, wherein in step 2, when the obtained zero sequence current amplitude on the line is greater than the set threshold, it is predicted that a power distribution network fault occurs, otherwise, the fault indicator continuously monitors the zero sequence current amplitude.
4. The method for locating the single-phase earth fault of the power distribution network based on the edge calculation according to claim 1, wherein the starting fault type sensing algorithm in the step 3 is used for identifying the fault type in a self-adaptive manner, and a transient process algorithm or a steady process algorithm corresponding to the identified fault type is selected to calculate the obtained three-phase current of the line; the method comprises the following specific steps:
step 3.1, phase currents in 5 periods before and after the moment of starting the fault type sensing algorithm are obtained, and zero-sequence current signals are synthesized;
step 3.2, filtering the synthesized zero sequence current signal by using improved S transformation to obtain a power distribution network fault line section corresponding to the accurate fault occurrence moment and a high-frequency component and a fundamental frequency component of the zero sequence current in a period after the fault occurrence;
step 3.3, establishing a self-adaptive sensing criterion after obtaining the amplitude by utilizing the high-frequency component and the fundamental frequency component, and respectively judging the fault type of the neutral point grounded fault or the resistance grounded fault through an arc suppression coil in the fault line section of the power distribution network;
step 3.4, when the type of the grounding fault of the neutral point passing through the arc suppression coil is judged, load current of the obtained three-phase current is filtered, and then a steady-state process algorithm is adopted for calculation; and when the type of the resistance earth fault is judged, the obtained three-phase current is subjected to load current filtering, and then transient process algorithm calculation is adopted.
5. The method for locating single-phase earth faults of power distribution networks based on edge computing as claimed in claim 4, wherein the adaptive sensing criterion established in step 3.3 is: k is A ·A 0 >A, when a self-adaptive sensing criterion is met, judging that a power distribution network fault line section has a resistance ground fault, otherwise, judging that a power distribution network fault line section has a neutral point ground fault through an arc suppression coil;
wherein: a is the amplitude of the high frequency component, A 0 Is the amplitude of the fundamental frequency component;
K A the value of the adaptive coefficient is 0.4-0.5.
6. The method for positioning single-phase earth fault of power distribution network based on edge calculation as claimed in claim 5, wherein the steady-state current characteristic obtained by combining the steady-state process algorithm in step 4 is used to make a positioning judgment of fault path or non-fault path for the line section which is predicted to have fault in the power distribution network, and the judgment is based on: the fault component of the fault phase on the fault path is larger than that of the non-fault phase, and the fault components of the non-fault phases are equal; the fault components of the three-phase currents on the non-fault paths are all the same.
7. The method for positioning single-phase earth fault of power distribution network based on edge calculation according to claim 5, wherein the phase current transient current characteristics obtained by combining the transient process algorithm in step 4 are used to make a positioning judgment of a fault path or a non-fault path for a line segment where a fault of the power distribution network is predicted, and the judgment method is as follows:
step 4.1, setting the processed fault component signals of the fault line section of the power distribution network as follows:
y＝f(x)
wherein x is a sampling point on a fault line section of the power distribution network, and y is a current value;
step 4.2, the sampling point corresponding to the fault occurrence moment obtained by improving S conversion is x 0 Simultaneously at sampling point x 0 A plurality of nearby calculation intervals are regulated for calculating the current value;
step 4.3, sampling point x at the moment of fault occurrence 0 Taking the corresponding function value as a reference value, and respectively taking the absolute value of the difference between the corresponding function value and the reference value in a plurality of calculation intervals according to the following formula:
y max ＝max{|f(x 0 +1)-f(x 0 )|，...，|f(x 0 +N)-f(x 0 )|}
wherein N is the number of the specified calculation interval, and the value is 1, 2, 3, 4 \8230;
step 4.4, find the maximum value y of the current from step 4.3 max Corresponding sampling point x max As mutation points:
x max ＝f -1 (y max )
step 4.5, comparing abrupt change direction results corresponding to three-phase currents on the same power distribution network fault line, and judging that the path is a fault path and an abrupt change direction different phase is a fault phase when two-phase current calculation results Dir are the same and the other phase current is different; and when the three-phase current calculation results Dir on the power distribution network fault line are the same, judging the path to be a non-fault path.
8. A distribution network single-phase earth fault positioning system based on edge calculation comprises a plurality of fault indicators installed on a distribution network line, and is characterized in that the fault indicators comprise a low-speed acquisition module, a trigger module, a high-speed data acquisition module, a memory, a data processor and a local judgment module;
the low-speed acquisition module is used for low-speed acquisition and data processing of the power distribution network line and pre-judging whether a power distribution network fault occurs or not;
the data high-speed acquisition module is used for circularly acquiring current data at a high speed through the FPGA and converting analog quantity into digital quantity;
when the low-speed acquisition module pre-judges that the power distribution network has a fault, the trigger module starts and sends out a pulse, the data high-speed acquisition module starts to acquire transient current data, and the acquired transient current data and the three-phase current data of the circuit are stored in the memory;
the data processor is internally provided with a fault type perception algorithm module which comprises a transient process algorithm or a steady-state process algorithm, wherein the transient process algorithm is used for obtaining phase current transient current characteristics, and the steady-state process algorithm is used for obtaining phase current steady-state current characteristics.
And the local judgment module is used for positioning and judging a fault path or a non-fault path of a line section which is pre-judged to have the power distribution network fault by combining the transient current characteristic and the steady-state current characteristic which are obtained by calculation of the data processor.
9. The system according to claim 8, wherein the fault indicator further comprises a communication module, and the data processor is configured to instruct the data in the memory to be uploaded to a master station through the communication module for centralized processing.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211107226.2A CN115656702A (en) | 2022-09-11 | 2022-09-11 | Power distribution network single-phase earth fault positioning method and system based on edge calculation |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211107226.2A CN115656702A (en) | 2022-09-11 | 2022-09-11 | Power distribution network single-phase earth fault positioning method and system based on edge calculation |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN115656702A true CN115656702A (en) | 2023-01-31 |
Family
ID=84983102
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202211107226.2A Pending CN115656702A (en) | 2022-09-11 | 2022-09-11 | Power distribution network single-phase earth fault positioning method and system based on edge calculation |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN115656702A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116626442A (en) * | 2023-06-06 | 2023-08-22 | 国网辽宁省电力有限公司抚顺供电公司 | Novel distribution network fault indicator based on edge calculation and application method thereof |
| CN116865430A (en) * | 2023-05-31 | 2023-10-10 | 河南水利与环境职业学院 | Online intelligent electricity safety identification system and method based on edge calculation |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104297639A (en) * | 2014-11-07 | 2015-01-21 | 广东电网有限责任公司电力科学研究院 | Fault traveling wave collecting device and system for medium voltage distribution network |
| CN113219300A (en) * | 2021-04-22 | 2021-08-06 | 华北电力大学 | Power distribution network single-phase earth fault sensing method based on phase current transient state steady state |
| CN114966326A (en) * | 2022-08-01 | 2022-08-30 | 国家电网有限公司 | Single-phase earth fault section positioning method and system based on current negative sequence fault |
-
2022
- 2022-09-11 CN CN202211107226.2A patent/CN115656702A/en active Pending
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104297639A (en) * | 2014-11-07 | 2015-01-21 | 广东电网有限责任公司电力科学研究院 | Fault traveling wave collecting device and system for medium voltage distribution network |
| CN113219300A (en) * | 2021-04-22 | 2021-08-06 | 华北电力大学 | Power distribution network single-phase earth fault sensing method based on phase current transient state steady state |
| CN114966326A (en) * | 2022-08-01 | 2022-08-30 | 国家电网有限公司 | Single-phase earth fault section positioning method and system based on current negative sequence fault |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116865430A (en) * | 2023-05-31 | 2023-10-10 | 河南水利与环境职业学院 | Online intelligent electricity safety identification system and method based on edge calculation |
| CN116865430B (en) * | 2023-05-31 | 2024-05-17 | 河南水利与环境职业学院 | Online intelligent electricity safety identification system and method based on edge calculation |
| CN116626442A (en) * | 2023-06-06 | 2023-08-22 | 国网辽宁省电力有限公司抚顺供电公司 | Novel distribution network fault indicator based on edge calculation and application method thereof |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN108957244B (en) | Single-phase earth fault line selection positioning method for distribution network main station | |
| Lotfifard et al. | Voltage sag data utilization for distribution fault location | |
| CN106646139B (en) | A kind of electrical power distribution network fault location method based on three-phase current amplitude analysis | |
| CN108448540B (en) | Zero sequence current comparison-based ground fault protection method for small-resistance grounding system | |
| CN115656702A (en) | Power distribution network single-phase earth fault positioning method and system based on edge calculation | |
| CN105242176B (en) | A kind of low current neutral grounding system fault localization method for being suitable for monitoring branched line | |
| JP2021148778A (en) | Failure position identification method based on transient state for ungrounded power distribution system | |
| CN109283431B (en) | Power distribution network fault section positioning method based on limited PMU | |
| CN107045093B (en) | Low-current single-phase earth fault line selection method based on quick S-transformation | |
| CN111308272B (en) | Positioning method for low-current ground fault section | |
| Aslan | An alternative approach to fault location on power distribution feeders with embedded remote-end power generation using artificial neural networks | |
| CN110045232B (en) | Method for identifying ground fault phase of neutral point non-effective grounding system | |
| CN111812451A (en) | Phase current transient fault component-based distributed line selection method for power distribution network | |
| CN106405285A (en) | Electric power system fault record data abrupt change moment detection method and system | |
| CN114966326B (en) | Single-phase earth fault section positioning method and system based on current negative sequence fault | |
| CN111413643A (en) | Power distribution network single-phase earth fault identification method | |
| CN112485598A (en) | Small current grounding fault positioning method combining waveform correlation and amplitude characteristics | |
| CN111413589A (en) | Power distribution network single-phase short circuit fault positioning method based on grey target decision | |
| CN111650470A (en) | Method for rapidly and adaptively detecting and identifying faults of microgrid circuit sections | |
| CN112731047A (en) | Fault line selection method suitable for flexible grounding system | |
| CN107462810B (en) | Fault section positioning method suitable for active power distribution network | |
| CN114441891A (en) | Power distribution network single-phase earth fault line selection method based on current signal similarity | |
| CN113156267B (en) | Power distribution network ground fault section selection method and system | |
| CN112485595B (en) | Power distribution network ground fault line selection protection method and device | |
| CN112269101B (en) | Single-phase disconnection fault positioning method for power distribution network with distributed power supply |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |