CN117406024A - Negative sequence reconstruction technology based on MK (modeling verification) and application method thereof in fault section positioning - Google Patents
Negative sequence reconstruction technology based on MK (modeling verification) and application method thereof in fault section positioning Download PDFInfo
- Publication number
- CN117406024A CN117406024A CN202311354754.2A CN202311354754A CN117406024A CN 117406024 A CN117406024 A CN 117406024A CN 202311354754 A CN202311354754 A CN 202311354754A CN 117406024 A CN117406024 A CN 117406024A
- Authority
- CN
- China
- Prior art keywords
- negative sequence
- reconstruction
- fault
- 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.)
- Granted
Links
- 238000000034 method Methods 0.000 title claims abstract description 40
- 238000005516 engineering process Methods 0.000 title claims abstract description 11
- 238000012795 verification Methods 0.000 title abstract description 7
- 238000012360 testing method Methods 0.000 claims description 12
- 230000007547 defect Effects 0.000 claims 1
- 238000000605 extraction Methods 0.000 claims 1
- 230000035945 sensitivity Effects 0.000 claims 1
- 238000004088 simulation Methods 0.000 abstract description 8
- 238000001514 detection method Methods 0.000 abstract description 5
- 230000005764 inhibitory process Effects 0.000 abstract description 2
- 238000010586 diagram Methods 0.000 description 14
- 238000011144 upstream manufacturing Methods 0.000 description 14
- 238000005259 measurement Methods 0.000 description 11
- 238000010248 power generation Methods 0.000 description 8
- 230000001052 transient effect Effects 0.000 description 3
- 230000007257 malfunction Effects 0.000 description 2
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 2
- 238000012544 monitoring process Methods 0.000 description 2
- 238000010998 test method Methods 0.000 description 2
- 241001495448 Impatiens <genus> Species 0.000 description 1
- 101100499229 Mus musculus Dhrsx gene Proteins 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 239000003245 coal Substances 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 229930190166 impatien Natural products 0.000 description 1
- 230000000977 initiatory effect Effects 0.000 description 1
- 230000004807 localization Effects 0.000 description 1
- 239000003345 natural gas Substances 0.000 description 1
- 239000003208 petroleum Substances 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 230000001629 suppression Effects 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/08—Locating faults in cables, transmission lines, or networks
- G01R31/088—Aspects of digital computing
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/08—Locating faults in cables, transmission lines, or networks
- G01R31/081—Locating faults in cables, transmission lines, or networks according to type of conductors
- G01R31/086—Locating faults in cables, transmission lines, or networks according to type of conductors in power transmission or distribution networks, i.e. with interconnected conductors
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F17/00—Digital computing or data processing equipment or methods, specially adapted for specific functions
- G06F17/10—Complex mathematical operations
- G06F17/14—Fourier, Walsh or analogous domain transformations, e.g. Laplace, Hilbert, Karhunen-Loeve, transforms
- G06F17/141—Discrete Fourier transforms
- G06F17/142—Fast Fourier transforms, e.g. using a Cooley-Tukey type algorithm
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F18/00—Pattern recognition
- G06F18/20—Analysing
- G06F18/21—Design or setup of recognition systems or techniques; Extraction of features in feature space; Blind source separation
- G06F18/213—Feature extraction, e.g. by transforming the feature space; Summarisation; Mappings, e.g. subspace methods
Landscapes
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Mathematical Physics (AREA)
- Theoretical Computer Science (AREA)
- Data Mining & Analysis (AREA)
- General Engineering & Computer Science (AREA)
- Computational Mathematics (AREA)
- Mathematical Analysis (AREA)
- Mathematical Optimization (AREA)
- Pure & Applied Mathematics (AREA)
- Computer Vision & Pattern Recognition (AREA)
- Discrete Mathematics (AREA)
- Software Systems (AREA)
- Databases & Information Systems (AREA)
- Algebra (AREA)
- Life Sciences & Earth Sciences (AREA)
- Artificial Intelligence (AREA)
- Bioinformatics & Cheminformatics (AREA)
- Bioinformatics & Computational Biology (AREA)
- Evolutionary Biology (AREA)
- Evolutionary Computation (AREA)
- Supply And Distribution Of Alternating Current (AREA)
Abstract
The invention belongs to the technical field of power failure section positioning, and discloses a negative sequence reconstruction technology based on MK (modeling, simulation and verification) and an application method. The method comprises the steps of providing a negative sequence reconstruction model based on negative sequence inhibition measures of a photovoltaic power supply, taking a negative sequence component as a fault characteristic quantity, and obtaining an optimal negative sequence reconstruction component by adopting a trend detection method to locate a fault section. Detecting the electric quantity of each measuring node in real time, and judging whether a negative sequence reconstruction starting criterion is met; establishing a negative sequence reconstruction model based on a symmetrical component method to realize negative sequence reconstruction; searching for an optimal negative sequence reconstruction component for optimal reconstruction which makes the fault feature most obvious by using a trend detection method; and calculating the effective value of the voltage amplitude and the current phase of the optimal negative sequence reconstruction component of each measuring node by using a fast FFT, and carrying out fault location according to a location criterion. The method is simple in principle, high in fault section positioning speed and easy to realize, and can be well applied to the photovoltaic power distribution network.
Description
Technical Field
The invention belongs to the technical field of power failure section positioning, and discloses a negative sequence reconstruction technology based on MK (modeling, modeling and application method in failure section positioning). The method aims to solve the problem that the traditional fault characteristic quantity can not correctly reflect a fault section in the distribution network of the photovoltaic power supply, and the optimal negative sequence reconstruction component is used as the fault characteristic quantity to realize the fault section positioning function under the conditions of symmetrical faults on the upstream side and symmetrical faults on the downstream side of the distribution network of the photovoltaic power supply and different accesses of DGs.
Background
With the rapid development of the electric power age, coal, petroleum, natural gas and the like which are only traditional non-renewable energy sources are harmful to the environment and cannot meet the increasing demands of people. Therefore, renewable clean energy sources such as light energy, wind energy, tidal energy and the like are widely applied. More and more new energy forms such as photovoltaic power generation are connected into a power grid.
The photovoltaic power generation is connected with a single-side power supply topological structure of the traditional power distribution network, so that double-side power supply can be formed. An upstream side fault of photovoltaic power generation possibly occurs, the photovoltaic power generation cannot timely detect a power distribution network fault, and an island effect that the photovoltaic power generation independently supplies power to a load and is not controlled by the power distribution network is formed; in addition, the photovoltaic power supply can provide fault current for fault points, forward fault current is provided to prolong the protection range of the protection element which should be operated, and reverse fault current is provided to shorten the backup protection range of the protection element which should not be operated even by misoperation. At present, the fault section positioning scheme of the power distribution network accessed by new energy sources such as photovoltaic power generation can be divided into two categories, wherein the first category is that the original relay protection configuration is not changed, but auxiliary elements are additionally arranged in the current protection to cope with the influence of the photovoltaic power supply access on the protection, such as directional elements (Zhu Lingling, li Changkai, zhang Huazhong, zhou Peiyi; power grid technology, 2009, 33 (14): 94-98) of the power distribution network containing the distributed power supply, but the overcurrent protection still can malfunction or refused to operate; the second type is to change the original protection configuration of the distribution network greatly, mainly there is regional protection based on multiple agents (Zhang Yanxia, generation impatiens; new feeder protection scheme [ J ] of distribution network with distributed power source, automation of power system, 2009, 33 (12): 72-74.), but this method does not solve the problem of cooperation of backup protection and next stage protection, and the previous stage backup protection may malfunction.
The achievement provides a negative sequence reconstruction technology based on MK (modeling, modeling and modeling) and a new method for application of the negative sequence reconstruction technology in fault section positioning, wherein a negative sequence component is used as a fault characteristic quantity of fault section positioning; providing a negative sequence reconstruction model with additional weight for a three-phase symmetrical fault scene without a negative sequence component; by adopting an MK trend detection method, the optimal reconstruction weight coefficient K which enables the fault characteristics to be most obvious is sought while ensuring that the negative sequence reconstruction component can reflect the fault section m Obtaining a negative sequence reconstruction sequence; and determining a suspicious fault section by utilizing the negative sequence reconstruction voltage amplitude, and further determining the fault section by utilizing the negative sequence reconstruction current phase direction to realize accurate positioning of the fault section of the distribution network of the photovoltaic power supply.
Disclosure of Invention
In order to solve the problems that the traditional three-section current protection cannot normally cut off faults and the like caused by photovoltaic power generation access, the invention provides a negative sequence reconstruction technology based on MK (modeling, modeling and application method thereof in fault section positioning. According to the fault section positioning scheme, negative sequence inhibition measures are adopted based on photovoltaic power generation, a photovoltaic power supply can be equivalent to a positive sequence power supply, when a power distribution network breaks down, the photovoltaic power supply only provides positive sequence components for fault points, a negative sequence topology network of a power network is not changed, and the negative sequence components are selected as fault characteristic quantities; creating an asymmetric condition based on a symmetric component method, assigning a weight value to any one of three phases, and extracting a negative sequence component; and selecting the optimal negative sequence component to locate the fault section based on an MK (kernel-based) test method.
The technical scheme adopted by the invention is as follows:
a negative sequence reconstruction technology based on MK test and a new method for applying the method in fault section positioning include the following steps:
step 1: judging whether a negative sequence reconstruction starting criterion is met when the power distribution network containing the photovoltaic power supply fails;
step 2: introducing a weight coefficient K to add weight to the single phase on the basis of a symmetrical component method, and carrying out negative sequence reconstruction;
step 3: statistics UF of each reconstructed sequence were calculated using Mann-Kendall (MK) test k Finding the optimal negative sequence reconstruction component;
step 4: and extracting the optimal reconstructed negative sequence voltage amplitude and current phase, and positioning the fault section according to the fault section positioning criterion.
The invention has the beneficial effects that:
(1) The negative sequence reconstruction model is provided, and the negative sequence component is used as a fault characteristic quantity, so that the photovoltaic power distribution network can accurately position a fault section under the conditions of symmetrical faults and asymmetrical faults.
(2) And the MK method is used for selecting the optimal negative sequence reconstruction component, so that the fault characteristic of the fault characteristic quantity is increased, and the rapid identification of the fault section is facilitated.
Drawings
FIG. 1 is a fault localization flow chart.
Fig. 2 is a schematic diagram of fault analysis of a photovoltaic power access distribution network.
Fig. 3 is a schematic diagram of a photovoltaic power distribution network system.
Fig. 4 is a schematic diagram of the negative sequence reconstruction start-up at the time of the upstream side symmetric failure.
Fig. 5 is a schematic diagram of negative sequence reconstruction selection during an upstream symmetric failure.
Fig. 6 is a schematic diagram of optimal negative sequence reconstruction selection k=1.1 at the time of upstream side symmetry failure.
FIG. 7 is a graph showing the comparison of the optimum negative sequence voltage amplitude at the time of the upstream side symmetrical fault.
Fig. 8 is a schematic diagram of the phase comparison of the optimal negative sequence current at the time of the upstream side symmetry fault.
Fig. 9 is a schematic diagram of the negative sequence reconstruction start-up at the time of the downstream side symmetry failure.
Fig. 10 is a schematic diagram of negative sequence reconstruction selection during a downstream side symmetric failure.
Fig. 11 is a schematic diagram of the optimal negative sequence reconstruction selection k=1.2 at the downstream side symmetry failure.
FIG. 12 is a graph showing the comparison of the optimum negative sequence voltage amplitude at the time of the downstream side symmetrical fault.
Fig. 13 is a schematic diagram showing the phase comparison of the optimal negative sequence current at the time of the downstream side symmetry failure.
Fig. 14 is a schematic diagram of a negative sequence reconstruction initiation at the time of a single DG access upstream side symmetric failure.
Fig. 15 is a schematic diagram of negative sequence reconstruction selection during a symmetric failure on the upstream side of a single DG access.
Fig. 16 is a schematic diagram of optimal negative sequence reconstruction selection k=1.1 for a single DG access upstream side symmetric failure.
Fig. 17 is a graph showing the comparison of the optimum negative sequence voltage amplitude for a single DG connected to an upstream side symmetric fault.
Fig. 18 is a schematic diagram of the best negative sequence current phase comparison for a single DG connected to an upstream side symmetric fault.
Detailed Description
The invention provides a negative sequence reconstruction technology based on MK test and a new method for application in fault section positioning, wherein the flow is shown in figure 1, and the method comprises the following steps:
step 1: and (3) starting negative sequence reconstruction:
1) Determining fault characteristic quantity: due to negative sequence suppression measures of the photovoltaic power supply, no negative sequence component is provided to the distribution network in case of failure. FIG. 2 shows a failure analysis of a photovoltaic power access distribution network;
wherein alpha is a proportionality coefficient of each section of feeder line, and the range of alpha is 0 to 1 by taking the outlet of the bus on the left side of the line as a reference point. Z is Z ∑I Equivalent negative sequence impedance, Z for line AI end load ∑BC Equivalent negative sequence impedance for the line BC and the load connected with the line BC; z's' 1 、Z′ 2 Line AI, AC impedance sum;is a negative sequence voltage drop across the lines AI, AC. The fault section 5 now flows through the negative sequence voltage, the current being determined only by the section line impedance and the fault point negative sequence voltage amplitude. E.g. formula (6)
Other non-faulty section negative sequence voltage and current as (7)
As can be seen from the analysis of the formulas (6) and (7), the negative sequence voltage amplitude at the fault point is the maximumThe negative sequence voltage amplitudes of the non-faulty sections 1, 2, 6, 7, 8 are all smaller than +.>The negative sequence voltage amplitude of the sections 3, 4 and 5 is greater than +.>Sequentially increasing on the basis. The negative sequence current flows from the fault point to both sides of the line, creating a negative sequence voltage drop across the line impedance. It follows that the closer to the fault point, the greater the negative sequence voltage magnitude. The negative sequence component is selected as the fault feature quantity.
2) And (3) starting negative sequence reconstruction: the negative sequence component only exists in the asymmetric fault, and when the three-phase symmetric fault occurs, the negative sequence reconstruction is started to create the negative sequence component. Judging whether the negative sequence reconstruction starting criterion is met or not, and extracting the negative sequence current I of each detection point when a fault occurs 2 Maximum phase currentAnd when the negative sequence reconstruction starting criterion is met, carrying out negative sequence reconstruction. Wherein the setting value is calculated as (8)
The maximum unbalance of the patent generates negative sequence current I 2.max Taking 4.9KA, maximum load current I L.max Taking 0.448KA and negative sequence current reliability coefficientTaking 1.15, phase current reliability coefficient +.>Take 1.25.
Step 2: negative sequence reconstruction is carried out:
1) And (3) electric quantity collection: the negative sequence reconstruction is suggested by adopting three-phase voltage and current of 2-4 transient power frequency periods after the fault. In consideration of fault positioning accuracy and electric quantity data processing workload, the patent carries out negative sequence reconstruction description on the electric quantity of 3 power frequency periods after fault occurrence.
2) Calculating each negative sequence component sequence: k (K) m Respectively obtaining weight coefficients K at 1-2 by equal step values of 0.1 1 、K 2 ……K 11 And brings each weight value and fault transient three-phase voltage into the step (2) to obtain 11 groups of reconstruction sequence negative sequence voltage componentsNegative sequence current component +.11 group reconstruction sequence>
Step 3: seeking the optimal weight coefficient:
1) Calculating statistics: negative sequence voltage component sequence X composed of n nodes of fault feeder line k As shown in formula (3); reconstruct 11 groupsNegative sequence voltage sequence S is constructed according to (4) k Rank sequence; based on the standard normal distribution, calculate S k Statistics of rank sequences UF k E.g. formula (9)
Wherein Uf k-1 ＝0，E(S k ) And Var (S) k ) Respectively S k Taking into account the mean and variance ofAre independent of each other and are distributed identically and continuously>
2) Selecting an optimal negative sequence reconstruction group: the sequence is given a significance level p, and for any K groups, if the statistics sequence has a trend of being larger than zero and smaller than zero, the sequence X is considered k There is a trend of increasing before decreasing, i.e. there is a maximum trend; when UF is k The greater the maximum, the closer to Uf p When it is considered that the sequence X k The more pronounced the trend of increase. Selecting UF with the most obvious trend M The group is the best negative sequence reconstruction group.
3) Calculating the optimal reconstruction weight coefficient: obtaining the optimal negative sequence reconstruction weight coefficient K according to the formula (5) m And taking the corresponding reconstructed negative sequence voltage and current sequence as the optimal negative sequence component reconstruction sequence.
Step 4: and (3) fault section positioning:
1) Extracting the amplitude of the optimal reconstructed negative sequence voltage component sequence to obtain U' A2_1 ,U′ A2_2 ,…,U′ A2_n ；
2) Selecting a maximum value U' A2_x Sub-maximum U' A2_y (x is not less than 1 and not more than n, y is not less than 1 and not more than n), if the two-value corresponding node is an adjacent node, directly judging the section as a fault section; if the two corresponding nodes are non-adjacent nodes, judging the area between the two nodes as a fault area;
3) Extracting the optimal reconstructed negative sequence current phase to obtainAiming at nodes in a fault area, comparing current phases, and selecting sections corresponding to two adjacent nodes with opposite current phases as fault sections.
Simulation verification: in order to verify the fault section positioning method (hereinafter, referred to as a positioning method) provided by the invention, a PSCAD/EMTDC simulation platform is utilized to build a photovoltaic power distribution network model shown in figure 3. The left side is a system power supply; the photovoltaic power supply is connected between the measuring points 5, 6 and 8, 9; and 5km of overhead lines are arranged between each two measuring points, and the total length of the lines is 55km. When the fault time is set to 0.2s, the detection and positioning method realizes the fault section positioning function under the conditions of upstream side symmetrical fault, downstream side symmetrical fault and DG different access. Calculating the available I according to the system parameters 2set ＝5.635KA，
1) Upstream side symmetric fault simulation verification: an ABC three-phase symmetrical fault is set for example between the measuring points 4, 5. Failure occurred at 0.02 s. Three-phase voltages and currents of all monitoring points in 3 transient periods after faults occur are read, whether negative sequence currents and maximum phase currents of all the monitoring points meet a negative sequence reconstruction starting criterion or not is judged, a negative sequence starting condition curve is set to be 1 when the negative sequence reconstruction starting condition curve is met, and time setting is not set to be 0 when the negative sequence starting condition curve is not met; carrying each reconstruction weight coefficient K into a negative sequence reconstruction model to obtain each reconstruction sequence, and selecting the optimal weight coefficient K by using an MK (nearest neighbor) test method m The method comprises the steps of carrying out a first treatment on the surface of the And extracting the optimal reconstructed negative sequence voltage negative sequence and current phase to locate the fault section. Simulation results are shown in fig. 4-8.
As can be seen from FIG. 4, the maximum negative sequence current I detected at this time 2M Less than the negative sequence current setting value I 2set The method comprises the steps of carrying out a first treatment on the surface of the Maximum value of three-phase currentLess than Xiang Dianliu constant->The negative sequence reconstruction starting criterion is satisfied, and the negative sequence reconstruction starting curve is 1.
As can be seen from fig. 5 and 6, among the 11 sets of statistics sequences, four sets of sequences corresponding to k=1.1, k=1.2, k=1.3, and k=1.4 satisfy that the sequences exist before being greater than 0 and then less than 0, and have a maximum trend; wherein k=1.1 corresponds to the statistic sequence UF k The maximum UF among the four sets of sequences was taken M = 2.038. Thus the optimal reconstruction coefficient K m ＝1.1。
As can be seen from fig. 7, the measurement points 4 and 5 correspond to two points with highest reconstructed negative sequence voltage amplitude, and the measurement points 4 and 5 are adjacent nodes, so that it can be determined that the measurement points (4 and 5) are fault sections; as can be verified from fig. 8, the negative sequence reconstructed currents of the measurement points 4 and 5 have opposite phases, and meet the fault section positioning criterion.
2) Downstream side symmetric fault simulation verification: an ABC three-phase symmetrical fault is provided for example between the measuring points 10, 11. Failure occurred at 0.02 s. The simulation results are shown in fig. 9-13.
As can be seen from FIG. 9, the maximum negative sequence current I detected at this time 2M Less than the negative sequence current setting value I 2set The method comprises the steps of carrying out a first treatment on the surface of the Maximum value of three-phase currentLess than Xiang Dianliu constant->The negative sequence reconstruction starting criterion is satisfied, and the negative sequence reconstruction starting curve is 1.
As can be seen from fig. 10 and 11, the sequence corresponding to k=1.2 in the 11 sets of statistic sequences satisfies that the sequence exists in the first period of more than 0 and then less than 0, and has the maximum trend; which corresponds to the statistics sequence UF k Maximum UF of (2) M =3.053. Thus the optimal reconstruction coefficient K m ＝1.2。
As can be seen from fig. 12, the measurement points 10 and 11 correspond to the two points with the highest reconstructed negative sequence voltage amplitude, and the measurement points 10 and 11 are adjacent nodes, and can be determined (10 and 11) as a fault section; it can be verified from fig. 13 that the negative sequence reconstructed currents of the measurement points 10,11 are opposite in phase, satisfying the fault section locating criterion.
3) And (3) fault section positioning adaptability verification of DG different access conditions: consider the case where only DG2 access is reserved and DG1 is taken out of operation. An ABC three-phase symmetrical fault is set for example between the measuring points 4, 5. Failure occurred at 0.02 s. Simulation results are shown in fig. 12-16.
As can be seen from FIG. 14, the maximum negative sequence current I detected at this time 2M Less than the negative sequence current setting value I 2set The method comprises the steps of carrying out a first treatment on the surface of the Maximum value of three-phase currentLess than Xiang Dianliu constant->The negative sequence reconstruction starting criterion is satisfied, and the negative sequence reconstruction starting curve is 1.
As can be seen from fig. 15 and 16, among the 11 sets of statistics sequences, four sets of sequences corresponding to k=1.1, k=1.2, k=1.3, k=1.4, and k=1.5 satisfy that the sequences exist before being greater than 0 and then less than 0, and have a maximum trend; wherein k=1.1 corresponds to the statistic sequence UF k The maximum UF among the four sets of sequences was taken M = 2.038. Thus the optimal reconstruction coefficient K m ＝1.1。
As can be seen from fig. 17, the measurement points 4 and 5 correspond to two points with highest reconstructed negative sequence voltage amplitude values, and the measurement points 4 and 5 are adjacent nodes, so that it can be determined that the measurement points (4 and 5) are fault sections; from fig. 18, it can be verified that the negative sequence reconstructed currents of the measurement points 4 and 5 have opposite phases, and meet the fault section positioning criterion.
Claims (5)
1. A negative sequence reconstruction technology based on MK test and an application method in fault section positioning are characterized in that: the application method comprises a negative sequence reconstruction starting criterion step, a negative sequence reconstruction model step based on single-phase additional weight, a negative sequence reconstruction optimal weight selection step based on MK test and a fault section positioning step based on reconstruction negative sequence.
2. The negative sequence reconstruction technique based on MK test and the application method in fault section positioning according to claim 1 are characterized in that: the negative sequence reconstruction starting criterion comprises the following steps: for the system without negative sequence component in the case of symmetrical fault, the protection based on the negative sequence component has defect, the negative sequence reconstruction is key, but the larger negative sequence component exists in the case of asymmetrical fault, the negative sequence reconstruction is not needed to be removed, and a negative sequence reconstruction starting criterion is established as shown in the formula (1)
Wherein I is 2M For the maximum negative sequence current detected;is the maximum value of three-phase current; i 2set Setting the negative sequence current according to the negative sequence current generated by avoiding the maximum unbalance; />For the phase current setting, the current setting is performed according to the maximum load.
3. The negative sequence reconstruction technique based on MK test and the application method in fault section positioning according to claim 1 are characterized in that: the negative sequence reconstruction model based on the single-phase additional weight comprises the following steps: changing negative sequence component extraction coefficient based on symmetrical component method, selecting any phase to increase weight coefficient, taking phase A as example, and implementing negative sequence reconstruction of three-phase voltage and current as formula (2)
In the method, in the process of the invention,is three-phase voltage; />Is three-phase current; />To reconstruct negative sequence voltage and current; alpha is a twiddle factor, alpha=e j120° ；K m For introducing weight coefficients, K is taken into account the symmetry of the symmetrical fault three-phase current m Taking 1-2; respectively obtaining weight coefficients K by taking values of 0.1 equal step length 1 、K 2 ……K 11 And each weight value is brought into (2) to obtain 11 groups of negative sequence voltage components of the reconstruction sequence +.>
4. The negative sequence reconstruction technique based on MK test and the application method in fault section positioning according to claim 1 are characterized in that: the negative sequence reconstruction optimal weight selection step based on MK test is as follows: to improve the protection sensitivity, a Mann-Kendall (MK) test is introduced to seek the best reconstructed negative sequence component;
step one: negative sequence voltage reconstruction with n nodes in the distribution network is provided, and the n node voltages are reconstructed into a negative sequence voltage component sequence as shown in the formula (3)
Wherein k=1-11, representing 11 sets of reconstructed negative sequence voltage sequences;a kth set of reconstructed negative sequence voltage components representing node n;
step two: constructing a rank sequence S according to the formula (4) by 11 groups of reconstructed negative sequence voltage sequences k ，S k ＝{s k-1 ,s k-2 ,…,s k-n }，
In the method, in the process of the invention,
step three: based on standard normal distribution and MK test principle, S is calculated k Statistics of rank sequences UF k ；
Step four: given the significance level p, UF with the most obvious trend is selected according to each statistic sequence M The group being the best negative sequence reconstruction group, i.e. the best negative sequence reconstruction weight coefficient K m
K m ＝1+0.1(M-1) (5)
M is the group, p=0.05 significant level was used, at which time, U p ＝Z 0.975 ＝±1.96。
5. The negative sequence reconstruction technique based on MK test and the application method in fault section positioning according to claim 1 are characterized in that: the fault section positioning step based on the reconstructed negative sequence is as follows: extracting a reconstructed negative sequence voltage amplitude value and a current phase, and carrying out fault location by combining fault section location criteria;
step one: extracting the optimal reconstructed negative sequence voltage amplitude, selecting the maximum value and the sub-maximum value, and directly judging the section as a fault section if the node corresponding to the two values is an adjacent node; if the two corresponding nodes are non-adjacent nodes, judging the area between the two nodes as a fault area;
step two: extracting the optimal reconstructed negative sequence current phase to obtainAiming at nodes in a fault area, comparing current phases, and selecting two adjacent nodes with opposite current phases as fault sections.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311354754.2A CN117406024B (en) | 2023-10-19 | Negative sequence reconstruction technology based on MK (modeling verification) and application method thereof in fault section positioning |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311354754.2A CN117406024B (en) | 2023-10-19 | Negative sequence reconstruction technology based on MK (modeling verification) and application method thereof in fault section positioning |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN117406024A true CN117406024A (en) | 2024-01-16 |
| CN117406024B CN117406024B (en) | 2024-05-24 |
Family
ID=
Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1996032652A1 (en) * | 1995-04-13 | 1996-10-17 | Siemens Aktiengesellschaft | Distance measurement process |
| CN103592984A (en) * | 2013-11-19 | 2014-02-19 | 电子科技大学 | Method for decomposing and reconstructing current instantaneous sequence component of triangular connection current transformer |
| CN107132450A (en) * | 2017-04-27 | 2017-09-05 | 上海电力学院 | A kind of marine double feedback electric engine stator winding inter-turn short circuit initial failure discrimination method |
| CN109142986A (en) * | 2018-10-10 | 2019-01-04 | 华北电力大学 | A kind of Fault Locating Method of AC power distribution line |
| US10989751B1 (en) * | 2020-10-27 | 2021-04-27 | North China Electric Power University | System and method of sparse voltage measurement-based fault location determination using intelligent electronic devices |
| CN112906250A (en) * | 2021-04-09 | 2021-06-04 | 吉林大学 | Complex system module classification method |
| CN116298699A (en) * | 2023-05-08 | 2023-06-23 | 合肥工业大学 | Power distribution network fault identification method based on wavelet optimization and graph convolution neural network |
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1996032652A1 (en) * | 1995-04-13 | 1996-10-17 | Siemens Aktiengesellschaft | Distance measurement process |
| CN103592984A (en) * | 2013-11-19 | 2014-02-19 | 电子科技大学 | Method for decomposing and reconstructing current instantaneous sequence component of triangular connection current transformer |
| CN107132450A (en) * | 2017-04-27 | 2017-09-05 | 上海电力学院 | A kind of marine double feedback electric engine stator winding inter-turn short circuit initial failure discrimination method |
| CN109142986A (en) * | 2018-10-10 | 2019-01-04 | 华北电力大学 | A kind of Fault Locating Method of AC power distribution line |
| US10989751B1 (en) * | 2020-10-27 | 2021-04-27 | North China Electric Power University | System and method of sparse voltage measurement-based fault location determination using intelligent electronic devices |
| CN112906250A (en) * | 2021-04-09 | 2021-06-04 | 吉林大学 | Complex system module classification method |
| CN116298699A (en) * | 2023-05-08 | 2023-06-23 | 合肥工业大学 | Power distribution network fault identification method based on wavelet optimization and graph convolution neural network |
Non-Patent Citations (6)
| Title |
|---|
| DU, X等: "《Simple current control method for three-phase VSC under unbalanced grid condition》", 《IET POWER ELECTRONICS》, 19 June 2018 (2018-06-19) * |
| ZHENXING LI等: "《Architecture and Fault Identification of Wide-area Protection System》", 《TELKOMNIKA》, 30 September 2012 (2012-09-30) * |
| 丁嘉等: "《图学习与零序分量相结合的风电场集电线单相接地故障定位》", 《电工技术学报》, 30 September 2023 (2023-09-30) * |
| 翁汉琍等: "《涌流引起换流变压器零序过电流保护误动的机理分析及对策》", 《电力系统自动化》, 31 May 2019 (2019-05-31) * |
| 胡满琳等: "《基于负序分量的含光伏电源配电网故障区段定位方法》", 《中国电力》, 29 January 2024 (2024-01-29) * |
| 贾科;董雄鹰;李论;冯涛;毕天姝;: "基于稀疏电压幅值量测的配电网故障测距", 电网技术, no. 03, 31 December 2020 (2020-12-31) * |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Dashti et al. | Fault location in power distribution network with presence of distributed generation resources using impedance based method and applying π line model | |
| Alsafih et al. | Determination of coherent clusters in a multi-machine power system based on wide-area signal measurements | |
| Brahma | Distance relay with out-of-step blocking function using wavelet transform | |
| US10288667B2 (en) | Method and system for fault detection and faulted line identification in power systems using synchrophasors-based real-time state estimation | |
| Fernandes et al. | Application of a phasor-only state estimator to a large power system using real PMU data | |
| Yin et al. | An improved iterative method for assessment of multi-swing transient stability limit | |
| CN108667005B (en) | Power grid static and dynamic combination vulnerability assessment method considering new energy influence | |
| CN108206541A (en) | A kind of distribution network electric energy quality disturbance source locating method containing distributed generation resource | |
| Sun et al. | Precise fault location in distribution networks based on optimal monitor allocation | |
| CN108336741A (en) | A kind of Contingency screening method and system of overall process Voltage stability analysis | |
| CN109378835A (en) | Based on the large-scale electrical power system Transient Stability Evaluation system that mutual information redundancy is optimal | |
| Li et al. | An integrated online dynamic security assessment system for improved situational awareness and economic operation | |
| Zhang et al. | Fault location based on voltage measurement at secondary side of low-voltage transformer in distribution network | |
| CN107462810A (en) | A kind of fault section location method suitable for active power distribution network | |
| Ghaedi et al. | Modified WLS three-phase state estimation formulation for fault analysis considering measurement and parameter errors | |
| Ma et al. | Pilot directional protection scheme for LCC-HVDC transmission lines based on the voltage difference between positive and negative poles | |
| CN117406024B (en) | Negative sequence reconstruction technology based on MK (modeling verification) and application method thereof in fault section positioning | |
| CN117406024A (en) | Negative sequence reconstruction technology based on MK (modeling verification) and application method thereof in fault section positioning | |
| Guha et al. | Real-time wide-area fault locator for power transmission networks using sparse PMU measurements | |
| Yi et al. | Development of wide area measurement and dynamic security assessment systems in Korea | |
| Barkakati et al. | A PMU based islanding detection scheme immune to additive instrumentation channel errors | |
| CN114325243A (en) | Oil field well site power distribution network fault judgment method based on line voltage amplitude variation | |
| Fan | Advanced fault area identification and fault location for transmission and distribution systems | |
| Pereira et al. | Location of single line-to-ground faults on distribution feeders using voltage measurements | |
| Idris et al. | Wide Area Fault Location for Power Transmission Network using Reactance Based Method |
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 | ||
| GR01 | Patent grant |