Method and system for topology based on carrier ranging

Abstract

The invention discloses a topology method and system based on carrier ranging, and mainly relates to the technical field of electricity utilization information acquisition. The method comprises the following steps: classifying all household meters in a transformer area according to three phases A, B and C based on an NTB zero-crossing technology of HPLC (High Performance Liquid Chromatography); based on the characteristic that signal attenuation between communication units of the same meter box and a branch box is very small, through SNR and attenuation information of communication signals, the meter boxes are grouped according to phases, after the meter boxes are grouped according to phases, three-phase fitting of the meter boxes is carried out according to the principle that loop impedance in front of a three-phase switch meter is consistent, and the three-phase box-meter relation in the meter boxes is obtained; power line distance measurement and phase topology identification are carried out through PLC signals, and three-phase fitting is carried out according to line impedance correlation. The method has the advantages that topology identification of the power supply network of the transformer area can be achieved, and accurate line loss analysis and electricity larceny prevention analysis are achieved on the basis.

Description

Technical Field

[0001] The present invention relates to the technical field of power consumption information collection, and specifically to a method and system for topology based on carrier ranging. Background Art

[0002] A large number of low-voltage power supply areas under the jurisdiction of power supply companies are responsible for the power supply services of industries, commerce and residents. With the increasingly refined management of the low-voltage distribution network by power grid companies, the traditional low-voltage area management means can no longer meet the requirements of the development of the intelligent power grid in the new era. There is an urgent need to promote the development of low-voltage area management towards the direction of intelligence and in-depth application on the basis of the original power consumption information collection system.

[0003] The equipment and topology diagrams in low-voltage areas change frequently, such as rural power grid transformation, meter box replacement, etc. If not recorded in time or recorded incorrectly, it will lead to inaccurate topology information. Moreover, during the construction and maintenance of the area, there may be errors in user electricity meter files or partial information missing; at the same time, in the existing technology, the method based on carrier communication is affected by clock synchronization, sampling error, etc., and the accuracy rate is relatively low. On the other hand, the analysis based on electrical quantity data such as voltage and current of the electricity meter is limited by the synchronization and accuracy of data collection, and it is also difficult to ensure high accuracy. Therefore, the core problems existing in the current low-voltage area are: 1. Unable to accurately identify the "transformer-line-household" relationship; 2. Unable to accurately conduct branch and sub-branch accurate line loss analysis, and lack of inexpensive means to achieve anti-stealing electricity management.

[0004] Therefore, there is an urgent need for a method and system for topology based on carrier ranging to solve the above problems. Summary of the Invention

[0005] The purpose of the present invention is to provide a method and system for topology based on carrier ranging, which can realize the topology identification of the power supply network in the area, and on this basis, realize accurate line loss analysis and anti-stealing electricity analysis.

[0006] To achieve the above object, the present invention is realized through the following technical solutions: On the one hand, a method for topology based on carrier ranging is provided, including the following steps: S1: Based on the NTB zero-crossing technology of HPLC, classify all household meters in the area according to three phases A, B, and C; S2: Group all area meters according to the carrier signal-to-noise ratio characteristics and cluster them by phase to obtain the three-phase box-meter relationship in the meter box; S3: Conduct power line ranging through PLC signals for phase-by-phase topology identification, and perform three-phase fitting according to the line impedance correlation.

[0007] Preferably, the step S1 is specifically: S11: Use HPLC technology for data acquisition. After the main node of the power distribution area receives the power distribution area identification instruction, it notifies the household meters. After an agreed delay time, the main node of the power distribution area and the household meters simultaneously collect the zero-crossing NTB; S12: After the acquisition is completed, the main node of the power distribution area sends the collected zero-crossing NTB to the household meters through HPLC. The household meters convert the zero-crossing NTB they collected and the received zero-crossing NTB into frequencies and compare them with the standard frequency; S13: Set the similarity threshold between two adjacent household meters, and calculate the cosine similarity of these two household meters to judge the phase relationship between the household meters. When the cosine similarity is greater than the set small similarity threshold, it is determined that the two household meters are in the same power distribution area; S14: The household meters that meet the set similarity threshold and are determined to be in different power distribution areas report the identification results to the main node of the power distribution area, and the main node of the power distribution area classifies the household meters; S15: Repeat steps S13 - S14 until all the household meters in the power distribution area are classified into three categories: A, B, and C.

[0008] Preferably, in step S2, all the power meters in the power distribution areas are clustered by phase according to the carrier signal-to-noise ratio characteristics, including the following steps: Use HPLC technology to monitor the carrier signal-to-noise ratio data of all the power meters in the power distribution areas in real time; Record the collected carrier signal-to-noise ratio data according to the time series and the meter identification; Preprocess the collected carrier signal-to-noise ratio data, including: removing outliers and noise, and extracting key features from the original carrier signal-to-noise ratio data, including: average value, variance, maximum value, and minimum value; According to the extracted key features, determine the number of clusters, and classify the household meters with similar carrier signal-to-noise ratio characteristics by phase.

[0009] Preferably, step S2 further includes: calculating the average voltage of the household meters clustered by phase, and fitting the data in the meter box according to the Pearson correlation coefficient method based on the material model with similar three-phase line impedances in the meter box.

[0010] Preferably, calculating the average voltage of the household meters clustered by phase specifically means: forming a data set of the household meters clustered by phase, and calculating the average voltage of each phase of the household meters in the data set respectively.

[0011] Preferably, fitting the data in the meter box according to the Pearson correlation coefficient method specifically means: For the voltage data matrix of n users and m acquisition points, it is expressed as follows: Find the voltage curves U i , U jPearson correlation coefficient: Only considering positive correlation, the three phases with the largest correlation and greater than the preset correlation are used as the fitting of the box-table relationship, and the three phases of the box-table relationship are correctly fitted.

[0012] Preferably, the step S3 is specifically as follows: The meter box performs branch identification by phase according to the carrier ranging method, performs phase-by-phase topology identification by performing power line ranging through the PLC signal, and fits the branches of the meter boxes clustered by phase according to the line impedance correlation.

[0013] The phase-by-phase topology identification by performing power line ranging through the PLC signal specifically includes the following steps: Obtain the ID codes of all signal receiving terminals, and send signals to control the states of the signal receiving terminals; After receiving the signal, detect the current direction through a notch filter and a current transformer; According to the current direction, the PLC identifies the parent nodes of each branch box and meter box, so as to obtain the topology diagram of the entire substation area.

[0014] Preferably, the meter boxes clustered by phase according to carrier ranging are specifically as follows: Adopt a two-level branch topology identification model. According to the communication topology, perform ranging on each node through the carrier ranging method, obtain the distances from the substation area center node to each household meter through the minimum spanning tree algorithm, assign carrier distance values to each meter box, obtain the voltage, current and power factor of the meter box through the measured values of the meters in the meter box, calculate the loop impedance before each switch according to the obtained voltage, current and power factor of the meter box. If the impedances are inconsistent, adjust the positions of the switches, replace damaged components or optimize the line layout to make the loop impedances before the three-phase switches reach a consistent or nearly consistent state, and perform three-phase branch fitting: Branch phase-by-phase loop voltage drop formula: U = U ， + I cosθ + I n cosθ Among them, U is the branch incoming line voltage, U is the average meter box voltage, I cosθ is the vector sum of the live wire currents of the meter box, and I n cosθ is the vector sum of the neutral wire currents of the meter box; If it is a meter box under the same branch, then R s is relevant, and the physical model of the meter boxes under the branch is: R s = R C + R N R C = U N - U ， / I cosθ R N = UN -U ， / I n cosθ For the voltage data matrix of n meter boxes and m acquisition points, it is represented as follows: Find the Pearson correlation coefficient of the voltage curves U i ,U j : Only considering positive correlation, when the three phases of this branch are balanced, as long as the line voltage drop changes by R C , the branch recognition correlation coefficient is set to the first set coefficient; when the three phases of this branch are unbalanced, the correlation coefficient is set to the second set coefficient at this time.

[0015] On the other hand, a system based on the above method of topology based on carrier ranging is provided, including: A household meter classification module for: classifying all household meters in the substation area into three phases of A, B, and C based on the NTB zero-crossing technology of HPLC; a three-phase box-meter relationship analysis module for: grouping the meter boxes of all substation area meters according to the carrier signal-to-noise ratio characteristics and clustering them by phase, and obtaining the three-phase box-meter relationship within the meter box; A meter box three-phase fitting module for: performing phase-by-phase topology recognition through power line ranging by PLC signals and performing three-phase fitting according to the line impedance correlation.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. Accurately identify the "transformer-line-household" relationship; 2. Precisely perform branch and sub-branch accurate line loss analysis, and can achieve anti-stealing electricity management through inexpensive means, reducing the maintenance cost of household meters in the substation area; 3. Based on the HPLC edge calculation sinking to the concentrator carrier communication module (CCO), using multi-dimensional correlation calculations such as the HPLC channel communication characteristics (SNR), HPLC carrier ranging method, and equipment load, and realizing the topology recognition of the substation area power supply network through big data analysis algorithms such as "SNR, carrier ranging, voltage correlation", and realizing accurate line loss analysis and anti-stealing electricity analysis on this basis. Brief Description of the Drawings

[0017] Figure 1 is the flowchart of the method of the present invention.

[0018] Figure 2 is the box-meter relationship diagram of the three-phase intelligent meter box for power supply in the substation area of the present invention. Detailed Embodiments

[0019] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by terms such as "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention.

[0020] In addition, the terms "first" and "second" are only used for descriptive purposes and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of the said features. In the description of the present invention, the meaning of "a plurality" is two or more unless otherwise specifically defined. In addition, the terms "mounted", "connected" and "coupled" should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection or an integral connection; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0021] The present invention will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and not to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms also fall within the scope defined by this application.

[0022] Embodiment: The working principle of power line carrier communication is to modulate the information signal onto a high-frequency carrier and then transmit it through the power line. At the receiving end, the received signal is demodulated and restored to the original information signal. This communication method utilizes the transmission characteristics of the power line to achieve long-distance transmission of information; if there is a delay in the propagation of the carrier signal on the power line. The carrier communication module has a 25Mhz high-precision clock (the time measurement accuracy can reach 40ns), the propagation speed of electromagnetic waves on a copper cable is about 2.3×10^8m / s, and the distance measurement accuracy S = V*t = 10m; the distance from the carrier main node CCO (PCCO) to each STA can be obtained by using the carrier.

[0023] For the line impedance, for a line with a diameter of 40mm applied according to the scale and calculated with a length of 100 meters, the line impedance is about 2 milliohms.

[0024] The impedance of the circuit can be expressed as: From the simplified branch box topology diagram, it can be obtained that: According to the formula, the topological impedance of the substation area power supply is calculated at the front end of the equipment. The shunt impedance under the same meter box has similarity. The farther the power supply radius of the substation area is, the larger the Ra value is. Since each Rdn under the same meter box is much greater than Rdn compared to Ra, the voltage drop of the power supply under the same meter box is basically affected by Ra, that is, R s ≈Ra, that is, Rd under the same meter box has a certain similarity.

[0025] As Figure 1 shown, the method for topology based on carrier ranging provided in this embodiment includes the following steps: S1: Based on the NTB zero-crossing technology of HPLC, classify all household meters in the substation area into three phases: A, B, and C; S2: Based on the characteristics of the communication units of the same meter box and branch meter boxes, group the meter boxes and obtain the three-phase box-meter relationship within the meter box; S3: Perform phase-by-phase topology identification through power line ranging using PLC signals and perform three-phase fitting according to the correlation of line impedance; In step S2, the specific grouping of the meter boxes is as follows: Based on the characteristic that the attenuation of the communication units of the same meter box and branch meter boxes is very small, group the meter boxes through the SNR and attenuation information of the communication signals; The specific method for obtaining the three-phase box-meter relationship within the meter box is as follows: According to the principle that the impedance of the circuit before the three-phase switch meter is the same, perform three-phase fitting of the meter box to obtain the three-phase box-meter relationship within the meter box.

[0026] Among them, step S1, that is, phase identification, is specifically as follows: S11: Use HPLC technology for data acquisition. After the main node of the substation area receives the substation area identification instruction, notify the household meters, and simultaneously collect the zero-crossing NTB after a predetermined delay time. The collection period is 2 seconds; S12: After the collection is completed, the main node of the substation area sends the collected zero-crossing NTB to the household meters through HPLC. The household meters convert the zero-crossing NTB they collected and the received zero-crossing NTB into frequencies and compare them with the standard frequency to obtain the valid data of the first point; S13: Set the similarity threshold between two adjacent household meters, and calculate the cosine similarity and Euclidean distance between these two household meters to determine the phase relationship between the household meters. When the similarity is greater than the set threshold, it is determined that the two household meters are in the same substation area; S14: The household meters that meet the set similarity threshold and are determined to be not in the local substation area will report the identification results to the main node of the substation area, and the main node of the substation area will classify the household meters; S15: Repeat steps S13 - S14 until all household meters in the substation area are classified into three categories: A, B, and C; In the unrecognized technology, an intelligent meter area identification method based on phasor measurement technology can accurately obtain phase information under high noise, harmonic interference, and fundamental wave dynamic changes by measuring the phasor information of power signals.

[0027] Step S2, that is, box-meter relationship identification, specifically: The box-meter relationship identification is divided into two steps. First, according to the carrier signal-to-noise ratio (SNR), all the area meters are clustered by phase according to the SNR characteristics. The household meters after clustering by phase form a data set, and the average voltage is calculated for each phase of household meters in the data set. According to the material model with similar three-phase line impedances in the meter box, data fitting in the meter box is performed in the way of Pearson correlation coefficient; The phase SNR, that is, the signal-to-noise ratio: is the ratio of signal strength to noise, mainly affected by attenuation and noise in the channel. In the power line, the two main factors affecting signal transmission are attenuation and noise. On the same line, the shorter the signal transmission distance, the less attenuation and noise it passes through, and the larger the signal-to-noise ratio. Moreover, when the signal is coupled through space, the attenuation is also relatively large. Generally, for the meters with the same phase in the same meter box, the SNR has the same changing trend, and this same trend is described by the correlation coefficient; Among them, clustering all the area meters by phase according to the carrier signal-to-noise ratio characteristics includes the following steps: Use HPLC technology to monitor the carrier signal-to-noise ratio data of all area meters in real time; Record the collected carrier signal-to-noise ratio data according to the time series and meter identification to ensure the integrity and accuracy of the data; Preprocess the collected carrier signal-to-noise ratio data, including: removing outliers and noise, and extracting key features from the original carrier signal-to-noise ratio data. The key features include: average value, variance, maximum value, and minimum value; According to the extracted key features, determine the number of clusters, and classify the household meters with similar carrier signal-to-noise ratio characteristics by phase.

[0028] The mathematical property of the Pearson correlation coefficient is that the change of two variables will not cause the change of this coefficient, that is, it is an invariant of this change (determined by the sign). In the same power supply environment, there is a random connection between the signal-to-noise ratio characteristics of communication and the current communication environment (such as background noise, etc.), but this relationship cannot be measured, and it is time-varying and irregular noise. However, this irregular random noise signal will be added to all the meters in the same meter box at the same time. That is, the signal-to-noise ratio characteristics of carrier communication in the same meter box (or adjacent meter boxes) have the same changing trend. In the phase power supply environment with different phases in the same meter box, if it is a three-phase branch, the materials and distances of the three-phase lines are basically similar, reflecting that the three-phase line impedances are basically the same, that is The line impedance is basically the same, such as Figure 2 As shown in the figure, the line impedance of each phase Ra, Rb, and Rc is set equal when designing the box-meter relationship power supply module, which is converted into the A, B, and C phase voltage U of the smart meter. A , U B , U C , relative to the voltage U of the total meter in the area N , their line impedance R s is a positive correlation coefficient; For n users, the voltage data matrix of m collection points is expressed as follows: Find the voltage curve U between any two users i ,U j The Pearson correlation coefficient is: Since it is an actual power supply line, only positive correlation is considered, and the three phases with the largest correlation and greater than 0.8 are found as the fitting of the box-meter relationship. In this way, the box-meter relationship and the three phases are correctly fitted.

[0029] Step S3, i.e., branch identification, is specifically: It is divided into two steps. First, the meter box uses the carrier ranging method to identify the branches by phase. Since the distance between branches is long (generally greater than 20 meters), the power line ranging is performed through the PLC signal to identify the phase topology. Then, the meter boxes clustered by phase are branch-fitted according to the line impedance correlation.

[0030] Meter boxes classified by carrier ranging and phase clustering: HPLC communication has the following functions: 1. The module has a built-in 25MHz high-precision crystal (CCO with temperature compensation), providing local high-precision timing accuracy of 40ns; through high-precision synchronization of the entire network, the frequency deviation is less than 1ppm (40ns) after correction, and the transmission distance mapped to the carrier signal is ≈10m 2. Fill in the high-precision timing timestamp of the sent message and the local locking timestamp of the high-precision timing timestamp of the received message (shielding the carrier processing and response time) 3: Delay measurement model: (Example: La = [(Ta4-Ta1)-(Ta3-Ta2)] / 2, Ta is the counter timestamp) Delay measurement model a: CCO-STA / PCO, routing table capability is directly accessible, direct path ranging.

[0031] Delay measurement model b: PCO-STA / PCO, the current routing table capability can be directly reached, and the segmented measurement is performed according to the routing table; among them, the power ranging is performed for the PLC signal, and its system composition includes: Signal transmission device: Installed at the root of the transformer, with a built-in power line broadband carrier (HPLC) communication module; Signal receiving terminal: Installed at the incoming or outgoing line end of the branch box and the meter box, with a built-in notch filter to block the 50Hz signal and communicate through a specific frequency signal; The working principle of power distance measurement for PLC signals is as follows: 1. The signal transmission device first obtains the ID codes of all signal receiving terminals and sends signals to control the status of the signal receiving terminals; 2. After receiving the signal, the signal receiving terminal detects the current direction through the notch filter and the current transformer; 3. According to the current direction, the system automatically identifies the parent nodes of each branch box and meter box, thereby obtaining the topology diagram of the entire substation area; for all signal receiving terminals in the terminal device list, the following operations are performed one by one: according to the ID, the signal transmission device sends an instruction to the signal receiving terminal to set it to the receiving state; all signal receiving terminals detected by the current transformer with current changes report information to the signal transmission device for storage; the signal receiving terminals in the receiving state are set to the idle state; the signal transmission device makes a judgment on all signal receiving terminals in the terminal device list one by one based on the collected data, finds their parent nodes, and thus generates the topology diagram of the entire substation area.

[0032] The secondary branch topology recognition model measures the distance to each node through carrier ranging according to the communication topology. The distance from the CCO to each STA is obtained through the minimum spanning tree algorithm. Since the box-meter relationship has been obtained in the second step, the algorithm assigns a carrier distance value to each meter box.

[0033] Line impedance correlation branch three-phase fitting: The voltage (average voltage of each meter), current (vector sum current), and power factor of the meter box are obtained through the measured values of the meters in the meter box. Based on the principle that the impedance of the front-end loop of the three-phase branch is similar, three-phase branch fitting is performed: Branch phase-by-phase loop voltage drop formula: U = U, + I cosθ + I n cosθ Among them, U is the branch incoming line voltage, U, is the average meter box voltage, I cosθ is the vector sum of the live wire currents of the meter box, and I n cosθ is the vector sum of the neutral wire currents of the meter box; If it is a meter box under the same branch, then R s is relevant, and the physical model of the meter boxes under the branch is: R s = R C + R N R C = UN -U ， / I cosθ R N =U N -U, / I n cosθ According to the Pearson correlation coefficient of the loop impedance, for the meter boxes under the same branch, R C and R N have a strong correlation; For the voltage data matrix of n meter boxes and m acquisition points, it is represented as follows: Find the Pearson correlation coefficient of the voltage curves U i , U j of any two users: Since it is an actual power supply line, only positive correlation is considered. If the three phases of this branch are balanced, as long as the line voltage drop change is RC, the branch identification correlation coefficient is set to 0.8; if the three phases are unbalanced (neutral line current > 2A and I' < 3In), the correlation coefficient is set to 0.7 at this time. Providing this method realizes meter box - branch identification.

[0034] This embodiment also provides a system based on the above method for topology based on carrier ranging, which is used to implement any of the above methods for topology based on carrier ranging.

[0035] The above has specifically described the preferred embodiments of the present invention, but the present invention is not limited to the described embodiments. Those skilled in the art can also make various equivalent deformations or substitutions without departing from the spirit of the present invention, and these equivalent deformations or substitutions are all included within the scope defined by the claims of this application.

Claims

1. A method for topology based on carrier ranging, characterized in that: The following steps are involved: S1: Based on the NTB zero-crossing technology of HPLC, all household meters in the area are classified into three phases: A, B, and C; S2: group all the area meters by phase clustering according to the carrier signal-to-noise ratio characteristics, and obtain the three-phase box-meter relationship in the meter box; S3: Power line ranging is performed through PLC signals to identify phase topology and three-phase fitting is performed based on line impedance correlation.

2. The method for topology based on carrier ranging according to claim 1, characterized in that: The step S1 is specifically: S11: Use HPLC technology to collect data. After receiving the area identification command, the area master node notifies the household meter. After the agreed delay time, the area master node and the household meter simultaneously collect zero-crossing NTB; S12: After the collection is completed, the main node of the substation area sends the collected zero-crossing NTB to the household meter through HPLC. The household meter converts the collected zero-crossing NTB and the received zero-crossing NTB into frequency and compares it with the standard frequency. S13: setting a similarity threshold of two adjacent household meters and calculating the cosine similarity of the two household meters to determine the phase relationship between the household meters. When the cosine similarity is greater than the set small similarity threshold, it is determined that the two household meters are located in the same area. S14: The household meters that meet the set similarity threshold and are determined to be in different areas report the identification results to the area master node, and the area master node classifies the household meters; S15: Repeat steps S13-S14 until all household meters in the area are divided into three categories: A, B, and C.

3. The method for topology based on carrier ranging according to claim 1, characterized in that: In step S2, all the electric meters in the substation area are clustered according to the carrier signal-to-noise ratio characteristics, including the following steps: Use HPLC technology to monitor the carrier signal-to-noise ratio data of all area meters in real time; The collected carrier signal-to-noise ratio data is recorded according to the time series and meter identification; Preprocessing the collected carrier signal-to-noise ratio data includes: removing outliers and noise, extracting key features from the original carrier signal-to-noise ratio data, including: mean value, variance, maximum value and minimum value; According to the extracted key features, the number of clusters is determined, and household meters with similar carrier signal-to-noise ratio characteristics are classified by phase.

4. The method for topology based on carrier ranging according to claim 3, characterized in that: The step S2 also includes: averaging the voltage of household meters after being clustered by phase, and fitting the data in the meter box according to the Pearson correlation coefficient method based on the material model with similar impedance of the three-phase line in the meter box.

5. The method for topology based on carrier ranging according to claim 4, characterized in that: The voltage average of the household meters clustered by phase is specifically: the household meters clustered by phase are formed into a data set, and the voltage average value is calculated for each phase household meter in the data set.

6. The method for topology based on carrier ranging according to claim 4, characterized in that: The data fitting in the table box is performed according to the Pearson correlation coefficient method, specifically: For n users, the voltage data matrix of m collection points is expressed as follows: Find the voltage curve U between any two users i ,U j The Pearson correlation coefficient is: Only the positive correlation is considered, and the three phases with the largest correlation and greater than the preset correlation are used as the fitting of the box-meter relationship, so as to correctly fit the three phases of the box-meter relationship.

7. The method for topology based on carrier ranging according to claim 5, characterized in that: The step S3 is specifically as follows: the meter box performs branch identification by phase using carrier ranging, performs power line ranging by PLC signal to perform phase topology identification, and performs branch fitting on the meter boxes clustered by phase according to line impedance correlation.

8. The method for topology based on carrier ranging according to claim 7, characterized in that: The method of performing power line ranging by PLC signal to identify phase topology specifically includes the following steps: Obtain the ID codes of all signal receiving terminals and send signals to control the status of the signal receiving terminals; After receiving the signal, the current direction is detected through the trap and current transformer; According to the current direction, the PLC identifies the parent node of each branch box and meter box, thereby obtaining a topological map of the entire substation.

9. The method for topology based on carrier ranging according to claim 6, characterized in that: The specific method of clustering meter boxes by carrier distance measurement and phase distance measurement is as follows: a two-level branch topology recognition model is used to measure the distance of each node according to the communication topology through carrier distance measurement. The distance from the central node of the substation to each household meter is obtained through the minimum spanning tree algorithm. The carrier distance value is assigned to each meter box. The voltage, current and power factor of the meter box are obtained through the measurement value of the meter inside the meter box. The loop impedance before each switch is calculated based on the voltage, current and power factor of the meter box. If the impedance is inconsistent, the loop impedance before the three-phase switch is consistent or nearly consistent by adjusting the position of the switch, replacing damaged components or optimizing the line layout, and performing three-phase branch fitting: the branch loop voltage drop formula by phase is: U=U ， +I cosθ+I n cosθ Among them, U is the branch line voltage, U ， is the average meter box voltage, I cosθ is the vector sum of the live wire current of the meter box, and I n cosθ is the vector sum of the current in the neutral line of the meter box; If the meter box is under the same branch, then R s Related, the physical model of the meter box under the branch is: R s =R C +R N R C =U N -IN ， / Icosθ R N =U N -U ， / I n cosθ For n meter boxes and m collection points, the voltage data matrix is ​​expressed as follows: Find the voltage curve U between any two users i ,U j The Pearson correlation coefficient is: Only positive correlation is considered. If the three phases of this branch are balanced, the line voltage drop change only needs to be R C , the branch identification correlation coefficient is set to the first setting coefficient; if the three-phase of this branch is unbalanced, the correlation coefficient is set to the second setting coefficient.

10. A system based on the method for topology based on carrier ranging according to claim 1, characterized in that: include: The household meter classification module is used to: classify all household meters in the area into three phases of A, B, and C based on the NTB zero-crossing technology of HPLC; The three-phase box-meter relationship analysis module is used to: group all the area electric meters according to the carrier signal-to-noise ratio characteristics and the phase clustering categories of the meter boxes, and obtain the three-phase box-meter relationship in the meter box; The meter box three-phase fitting module is used to: perform power line ranging through PLC signals to identify phase topology and perform three-phase fitting based on line impedance correlation.

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