A topology identification method and system based on GNSS and synchronized phasors

Abstract

The present invention provides a topology identification method and system based on GNSS and synchronous phasors, including: obtaining a time synchronization signal through GNSS; using a hardware controller to control an analog-to-digital converter to perform data sampling according to a specified sampling rate and sampling time; in a control terminal, using software to process the sampled data, executing a synchronous phasor measurement algorithm, and obtaining synchronous phasor data; performing data processing tasks in a multi-core processor architecture; uploading the processed synchronous phasor data to a master control station through a network; the master station receives the synchronous phasor data and GNSS information, and performs preliminary topology identification; further topology identification is performed using the synchronous phasor data; and the identified topology information is updated to the master station system. The present invention automatically identifies the distribution network topology without manual calibration. When the distribution network topology changes, the system can dynamically update the topology information, provide real-time and accurate power grid topology information, and reduce the difficulty and workload of distribution network operation management.

Description

Technical Field

[0001] The present invention relates to the technical field of electric power systems and power grids, and in particular to a topology identification method and system based on GNSS and synchronous phasors. Background Art

[0002] In my country, the 10kV distribution network is the backbone network, and its topological connection relationship has become increasingly complex with years of investment in distribution network construction. There are different wiring methods and variable operation modes in the distribution network, which not only increases the difficulty of distribution network operation and management, but also brings a heavy workload for maintenance management such as setting and feeder automation, and also creates many operational risks. In this case, how to accurately identify the topology of the 10kV distribution network has become a long-term and thorny problem faced by the power sector.

[0003] Global Navigation Satellite Systems (GNSS) can provide accurate time and location information, including China's BeiDou Navigation Satellite System (BDS), the United States' Global Positioning System (GPS), Russia's GLONASS and the European Union's Galileo. These systems can provide global users with all-weather, all-day, high-precision positioning, navigation and timing services. In particular, China's BeiDou system, as a global satellite navigation system independently built and operated by the country, provides important technical support for the domestic power system.

[0004] In the distribution network, automation control equipment such as FTU (feeder automation terminal), DTU (station terminal) and TTU (distribution transformer area fusion terminal) have been widely deployed, and they are important components of distribution network automation. However, due to the complexity of the distribution network topology and the variability of operation modes, how to accurately identify the real-time topology of the 10kV distribution network and how to determine the actual connection relationship between electrical equipment is still an unresolved problem.

[0005] Phasor measurement is a commonly used measurement technology in power systems. It can provide information about the amplitude and phase of current and voltage, providing important data support for real-time monitoring and analysis of power grids. Usually, phasor measurement uses discrete Fourier transform (DFT) or fast Fourier transform (FFT) to calculate phasors to obtain the amplitude and phase of current and voltage. This measurement technology provides key data support for real-time monitoring and analysis of power grids, but how to use phasor measurement data to achieve accurate distribution network topology identification under complex distribution network topology and changing operation modes is still a challenging problem.

[0006] In summary, the problem of 10kV distribution network topology identification has not been fully solved, and new technical solutions need to be found to improve the accuracy and efficiency of distribution network topology identification to meet the needs of modern power system operation and management. Summary of the invention

[0007] In order to overcome the shortcomings of the prior art, the present invention proposes a topology identification method and system based on GNSS and synchronous phasors, which can identify the topological structure of a 10kV distribution network in real time, including the location of equipment, electrical connection relationships, etc., provide accurate topological information for the operation and maintenance of the power system, and can effectively reduce operational risks, optimize constant value setting and feeder automation.

[0008] To achieve the above object, the present invention provides a topology identification method based on GNSS and synchronized phasors, comprising:

[0009] Step S1: Obtaining a time synchronization signal through a global navigation satellite system (GNSS) to ensure that all devices in the system can operate under the same time reference;

[0010] Step S2: using a hardware controller (such as FPGA) to control an analog-to-digital converter (ADC) to perform data sampling at a specified sampling rate;

[0011] Step S3: In the control terminal, the sampled data is processed by software, the phasor measurement algorithm is executed, and the synchronized phasor data is obtained;

[0012] Step S4: In a multi-core processor architecture, one core is responsible for management tasks (such as task scheduling, configuration parsing, communication, etc.), and the other core is responsible for real-time computing tasks; perform necessary data processing tasks, including data analysis, error detection and correction, etc.; upload the processed synchrophasor data to the master control station through the network for further analysis and monitoring;

[0013] Step S5: The master station receives the synchronized phasor data and GNSS information sent from the distribution network terminal, and performs preliminary topology recognition based on the received GNSS information to determine the possible electrical connection relationship and device location.

[0014] Step S6: using the synchronized phasor data to further refine the topology identification, determine the real-time topology of the power grid, and identify the actual connection relationship between the electrical devices;

[0015] Step S7: Update the identified topology information to the master station system to provide real-time and accurate power grid topology information for subsequent monitoring and control.

[0016] Further, step S1 includes:

[0017] Step S11: configuring and starting a GNSS receiver to receive a time synchronization signal from a global navigation satellite system (GNSS).

[0018] Step S12: Analyze the GNSS signal, obtain accurate time information, and set this time information as the time base of the system.

[0019] Step S13: Propagate the time synchronization signal to all devices in the system to ensure that all devices can operate under the same time reference.

[0020] Further, step S3 includes:

[0021] Step S31: In the control terminal, implement the phasor measurement algorithm and prepare to process the sampled data.

[0022] Step S32: using the implemented algorithm to process the sampled data and obtain synchronized phasor data.

[0023] Step S33: verify the acquired synchronized phasor data to ensure the accuracy and integrity of the data.

[0024] Further, step S4 includes:

[0025] Step S41: In a multi-core processor architecture, core tasks are configured and allocated, with one core responsible for management tasks (such as task scheduling, configuration analysis, communication, etc.) and another core responsible for real-time computing tasks.

[0026] Step S42: Execute necessary data processing tasks in the designated core, including data analysis, error detection and correction, etc.

[0027] Step S43: Upload the processed synchronized phasor data to the master control station via the network for further analysis and monitoring.

[0028] Step S44: confirm that the data has been successfully uploaded to the master control station, and provide feedback on the upload status if necessary.

[0029] Further, step S5 includes:

[0030] Step S51: the master station receives the synchronized phasor data and GNSS information sent by the distribution network terminal through the network;

[0031] Step S52: Verify the integrity and accuracy of the received data to ensure that the data is not lost or damaged during transmission;

[0032] Step S53: performing necessary preprocessing operations on the received data, such as denoising, format conversion, timestamp correction, etc., to prepare for further topology identification;

[0033] Step S54: using the received GNSS information, performing preliminary identification of electrical equipment locations and connection relationships, and constructing a preliminary topology model;

[0034] Step S55: Determine possible electrical connection relationships and potential electrical contact points based on geographic information and basic properties of electrical equipment.

[0035] Further, step S6 includes:

[0036] Step S61: using the amplitude and phase information of the synchronized phasor data, further analyzing the actual connection relationship between the electrical devices.

[0037] Step S62: Determine the actual electrical connection status between the devices by comparing the phasor data between different devices.

[0038] Step S63: According to the results of the phasor data analysis, the initially identified topology model is optimized and corrected to obtain a more accurate grid topology structure.

[0039] Further, step S7 includes:

[0040] Step S71: updating the result of fine topology identification to the topology database of the master station to ensure the real-time accuracy of the topology information;

[0041] Step S72: Save the identified topology information in a database and perform necessary backup operations to prevent data loss or damage;

[0042] Step S73: When a change in the grid topology is detected, the relevant monitoring and control systems are notified in a timely manner to ensure the accuracy and safety of system operation.

[0043] Furthermore, it also includes data quality assessment and anomaly detection, as follows:

[0044] Step S81: designing data quality assessment criteria, such as missing rate, noise level, consistency, etc., to assess the quality of the collected synchronized phasor data;

[0045] Step S82: monitor data quality in real time and send an alarm when data quality deteriorates;

[0046] Step S83: Construct an anomaly detection model as follows:

[0047] [s(x,n)=2^{-left(frac{E(h(x))}{c(n)}right)}]

[0048] Where: (x) is a data point;

[0049] (n) is the sample size;

[0050] (E(h(x))) is the average path length of a data point (x) in all trees;

[0051] (c(n)) is a correction factor, which is usually used to adjust the range of anomaly scores.

[0052] A topology identification system based on GNSS and synchronized phasors is applicable to the above-mentioned topology identification method based on GNSS and synchronized phasors, comprising:

[0053] A time synchronization module, which includes a GNSS receiver submodule and a time synchronization control submodule, which are respectively responsible for receiving and parsing GNSS signals to obtain accurate time synchronization signals and for distributing synchronization signals to all devices and modules in the system;

[0054] The data acquisition module includes a hardware control submodule and an ADC submodule. The hardware control submodule is responsible for controlling the ADC and performing data sampling at a specified sampling rate; the ADC submodule is responsible for converting analog signals into digital signals;

[0055] The data processing module is responsible for processing the sampled data, executing the phasor measurement algorithm, and obtaining the synchronized phasor data.

[0056] The multi-core processing module includes a management core module and a real-time computing core module. The management core module is responsible for management tasks such as task scheduling, configuration analysis, and communication. The real-time computing core module is responsible for executing real-time computing tasks such as data analysis, error detection and correction, etc.

[0057] The data upload module is responsible for uploading the processed synchrophasor data to the master control station through the network;

[0058] The preliminary topology recognition module is responsible for processing the received GNSS information and performing preliminary topology recognition;

[0059] A refined topology identification module is used to further determine the real-time topology of the power grid using synchronized phasor data and to identify the actual connection relationship between electrical equipment;

[0060] The topology information update module is responsible for updating the identified topology information to the master station system.

[0061] Compared with the prior art, the present invention has the following beneficial effects:

[0062] 1. The present invention provides a topology identification method and system based on GNSS and synchronous phasors, which can identify the topology structure of a 10kV distribution network in real time, including the location of equipment, electrical connection relationships, etc., and provide accurate topology information for the operation and maintenance of the power system. This is of great significance for reducing operational risks, optimizing set value setting, feeder automation and other maintenance and management tasks.

[0063] 2. The present invention provides a topology identification method and system based on GNSS and synchronized phasors, which can achieve high-precision, high-rate synchronous sampling and data processing through high-precision clock synchronization of GNSS and analog-to-digital converter (ADC) technology controlled by FPGA. In addition, the multi-core processor architecture can ensure the efficient execution of real-time computing tasks and management tasks, and improve the accuracy and real-time performance of data processing.

[0064] 3. The present invention provides a topology identification method and system based on GNSS and synchronous phasors, which can automatically identify the distribution network topology without manual calibration. When the distribution network topology changes, the system can dynamically update the topology information, provide the power management department with real-time and accurate power grid topology information, and reduce the difficulty and workload of distribution network operation management.

[0065] 4. The present invention provides a topology identification method and system based on GNSS and synchronous phasors. Through real-time topology identification and synchronous data processing, the power management department can better monitor and control the operating status of the distribution network, timely discover and deal with potential problems, and enhance the safety and stability of the power grid.

[0066] 5. The present invention provides a topology identification method and system based on GNSS and synchronous phasors, which can provide real-time data support for further identification of power management departments or power equipment, help power system operators better understand and analyze the operating conditions of the power grid, and provide a data basis for the optimized operation of the power system. BRIEF DESCRIPTION OF THE DRAWINGS

[0067] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0068] Figure 1 It is a schematic diagram of the process of the present invention;

[0069] Figure 2 It is a hardware system architecture diagram of the present invention;

[0070] Figure 3This is a diagram of the internal structure of the GNSS module of the present invention;

[0071] Figure 4 It is a schematic diagram of AD sampling;

[0072] Figure 5 This is a synchronous sampling logic block diagram;

[0073] Figure 6 Define the diagram for the phase angle and pulse per second of the synchronized phasor;

[0074] Figure 7 This is the synchronous phasor calculation model diagram;

[0075] Figure 8 It is a diagram of the board interrupt generation and synchronization process;

[0076] Fig. 9 To obtain the initial topological relationship diagram of the device according to the geographical location information of GNSS;

[0077] Fig.10 Identify logical blocks for association relationships;

[0078] Fig.11 Identify logical blocks for topological relationships;

[0079] Fig.12 The master station further selects and identifies the connection relationship diagram between devices in combination with the synchronization vector information;

[0080] Fig.13 This is the electrical diagram for the pilot project in Huai'an, Jiangsu. DETAILED DESCRIPTION

[0081] The technical solution of the present invention will be more clearly and completely explained below through description of preferred embodiments of the present invention in combination with the accompanying drawings.

[0082] like Figure 1 As shown, the present invention is specifically:

[0083] A topology identification method based on GNSS and synchronized phasors, comprising:

[0084] Step S1: Obtaining a time synchronization signal through a global navigation satellite system (GNSS) to ensure that all devices in the system can operate under the same time reference;

[0085] Step S2: using a hardware controller (such as FPGA) to control an analog-to-digital converter (ADC) to perform data sampling at a specified sampling rate;

[0086] Step S3: In the control terminal, the sampled data is processed by software, the phasor measurement algorithm is executed, and the synchronized phasor data is obtained;

[0087] Step S4: In a multi-core processor architecture, one core is responsible for management tasks (such as task scheduling, configuration parsing, communication, etc.), and the other core is responsible for real-time computing tasks; perform necessary data processing tasks, including data analysis, error detection and correction, etc.; upload the processed synchrophasor data to the master control station through the network for further analysis and monitoring;

[0088] Step S5: The master station receives the synchronized phasor data and GNSS information sent from the distribution network terminal, and performs preliminary topology recognition based on the received GNSS information to determine the possible electrical connection relationship and device location.

[0089] Step S6: using the synchronized phasor data to further refine the topology identification, determine the real-time topology of the power grid, and identify the actual connection relationship between the electrical devices;

[0090] Step S7: Update the identified topology information to the master station system to provide real-time and accurate power grid topology information for subsequent monitoring and control.

[0091] As a specific implementation method, the hardware system is shown as follows Figure 2 As shown in the figure, the typical hardware circuit of distribution automation equipment is the minimum system with MCU+FPGA as the core. The modules are described as follows:

[0092] DCDC, power conversion module - completes the external power conversion function, converts the external DC power supply (usually one of DC220V, DC110V, DC48V, DC24V) into the power supply voltage level required by this minimum system, such as DC3.3V, 2.5V, 1.8V, 1.2V, 1.0V, etc. as the power supply for each functional device;

[0093] ADC chip, analog to digital conversion module - as an analog acquisition and conversion module, it collects small analog signals from the backplane bus at high speed inside the chip and converts them into digital signals with a data accuracy of 16 bits (the ADC chip selected for this system is AD7606 from ADI);

[0094] For the distribution network terminal equipment, the external analog quantities connected are voltage signals and current signals. For the 10kV application scenario, the terminal connected voltage is the voltage converted to the secondary voltage by the voltage sensor, the rated voltage is 100V (PP), and the range is usually 2 times the rated value; the terminal connected current is the current converted to the secondary current by the current sensor, the secondary rated current is 1A or 5A, and the range is 20 times the rated value.

[0095] MCU, central processing unit chip - is the control center of the system, completing the management and information exchange of related peripherals, as well as the calculation and logic processing tasks inside the chip. (The MCU selected for this system is Xilinx's XC7Z020-2CLG400I, PS side, main frequency 700MHz, with A9 dual-core, one core loaded with Linux operating system, completes communication and management functions; the other core is naked, centrally processing high-real-time tasks)

[0096] FPGA, programmable gate array - composed of programmable logic units and programmable resources, assists MCU to complete some logic operations with high real-time requirements and parallel computing characteristics, as well as external resource expansion, such as network ports, serial ports and GPIO. (The FPGA selected for this system is Xilinx's XC7Z020-2CLG400I, and the programming method is VHDL)

[0097] DDR, memory chip - used to provide real-time storage resources and cooperate with MCU to complete calculation and logic processing;

[0098] NOLASH, program storage chip - used to provide program storage space to store programs running in the MCU;

[0099] NVRAM, non-volatile memory chip - used to store key data, such as related device parameters;

[0100] PHY, network interface chip - is an integrated circuit used to implement computer networks and communication equipment. PHY chip controller chip is used in conjunction to exchange data.

[0101] PowerMonitor——power monitoring circuit, used to monitor the power supplies used by the chip to ensure they are within the allowable range, and to promptly issue an alarm and lock the system in case of voltage exceeding the limit to ensure system safety.

[0102] 4G communication module - The main function of the 4G communication module in this scenario is to interact with data and transmit wireless information between the distribution network terminal and the master station. The module model used in this system is EC20CEHDLG-128-SNNS from Quectel.

[0103] EC20 R2.1 adopts LTE 3GPP Release 11 technology, supporting a maximum downlink rate of 150Mbps and a maximum uplink rate of 50Mbps. At the same time, it is compatible with Quectel's multi-network LTE EC21 series, EC25 series and EG25-G modules in terms of packaging, achieving seamless switching between 3G and 4G networks.

[0104] EC20 R2.1 has built-in rich network protocols, integrates multiple industrial standard interfaces, and supports multiple drivers and software functions, which greatly expands the application scope of EC20 R2.1 in the M2M field.

[0105] The features of the EC20 module are:

[0106] a. LTE Cat 4 wireless module designed for M2M and IoT applications

[0107] b. Comprehensive coverage of all network standards

[0108] c. Integrate multi-constellation GNSS receivers to meet the needs of fast and accurate positioning in different environments

[0109] d.Support DFOTA and DTMF functions

[0110] e.MIMO technology meets the requirements of wireless communication systems for data rate and connection reliability

[0111] GNSS module - positioning and timing module, which calculates the position by receiving signals from multiple satellite systems and obtains accurate absolute time (the GNNS module model selected for this system is UM220-IVL, which is a GNSS multi-system, high-precision timing module. It is designed based on the multi-system, low-power, high-performance SoC chip-UFirebird with completely independent intellectual property rights. It supports BDS, GPS, GLONASS and Galileo systems, and can receive and process two or three of them at the same time, or work independently as a single system. It supports SBAS, QZSS system and DGNSS data input functions, has advanced AGNSS functions, and can improve positioning speed through the auxiliary data service of Unicore Starlink when connected to the Internet).

[0112] The internal structure of the GNSS module is as follows: Figure 3 As shown,

[0113] The RF signal of the UM220-IVL Beidou / GPS dual-mode antenna receiver is first input into the RF IC chip through a low noise amplifier (LNA) and a surface acoustic wave filter (SAW). The RF chip converts the RF signal into a baseband signal through frequency synthesis and frequency conversion, and despreads and demodulates the baseband signal, using pseudo code measurement and carrier phase measurement technology to measure the position, speed, time and other parameters (PVT original value). The SOC receives the PVT original value of the RF signal, performs navigation processing and timing processing, and provides users with navigation positioning, timing and other services.

[0114] The key technical indicators of UM220-IVL are positioning accuracy and timing accuracy. The static horizontal positioning accuracy of UM220-IVL is better than 10m; the static elevation positioning accuracy is better than 10m. The timing accuracy of UM220-IVL, 1PPS output uncertainty should be better than 50ns.

[0115] UM220-IVL supports three timing modes: fixed point timing, optimized position timing, and positioning timing. The timing mode can be switched and queried through the CFGTM command. UM220-IVL can track GPS, BDS, GLONASS, Galileo and other systems, and the system can be switched through the CFGGNSS command.

[0116] The UM220-IVL module is configured by default to optimize the position timing mode. The module can output real-time position and fixed-point position information, which can be queried through the TIMPOS statement.

[0117] The fixed-point timing mode is only for timing applications in static scenarios. In this mode, the user needs to enter the exact center position of the receiver antenna through the CFGTM command. UM220-IVL uses this accurate position to calculate the distance between the antenna and the satellite, and calculate the time for timing.

[0118] The optimized position timing mode is also a timing application in a static scenario. In this mode, the receiver collects a certain number of positioning points (observation time) and calculates these positioning points to obtain the exact position of the antenna. After that, this position is locked and switched to the fixed-point timing mode, and fixed-point timing is performed based on the locked position.

[0119] The observation time and observation accuracy are set by the CFGTM command. Both conditions must be met at the same time to enter the fixed-point timing mode. The observation status can be queried through TPFINFO.

[0120] The position estimation process only needs to be performed once after the UM220-IVL is installed. After the position optimization is completed, the timing mode in the receiver settings will automatically switch to fixed-point timing mode.

[0121] In the hardware system of automatic control equipment, a GNSS module is added, and its core functions are as follows:

[0122] The first is to obtain geographic location information. The MCU sends the information to the main station via the 4G module in the form of wireless communication as the location information of the control device and the associated distribution network switch.

[0123] Second, the GNSS module inputs the pulse per second signal (PPS) into the FPGA. The ADC sampling module of the FPGA performs synchronous sampling calculations based on the PPS signal, combines it with the timing information of the GNSS, forms synchronous vector data (voltage and current) with time stamps, and sends this electrical data to the master station.

[0124] like Figure 4 As shown in the figure, this method uses the electrical quantity synchronous phasor acquisition technology based on high-precision clock. According to the PPS signal (second pulse signal) sent by GNSS, the whole second is divided into equal parts according to the sampling rate within a strict whole second interval. Taking the sampling rate of 12800 points / second as an example, the FPGA divides the whole second into equal parts according to this sampling rate, and the equal division interval is 78.125us. FPGA adjusts the sampling time of the analog quantity sampling conversion chip (ADC, such as AD7606) so that the sampling interval and sampling time of the ADC chip are strictly in accordance with the equal division interval.

[0125] Because all automation control devices in the distribution network area are based on the same GNSS reference, the sampling time and sampling interval of each device are synchronized in the absolute time dimension, providing a synchronized measurement data source for the calculation of the synchronous vector; the synchronous sampling logic is as follows: Figure 5 shown.

[0126] In the distribution network control terminal, based on the synchronous sampling data of analog quantity, the software implements the synchronous phasor measurement algorithm to obtain the synchronous phasor with time stamp. The specific algorithm is summarized as follows:

[0127] The voltage and current signals of the AC power system can be represented by phasors, which consist of two parts, namely the amplitude X (effective value) and the phase angle The synchrophasor phase angle is expressed as real and imaginary parts in rectangular coordinates. The synchrophasor phase angle uses a high-precision synchronous clock (GPS, BeiDou) as a reference. According to the IEEE C37.118.1-2011 standard, for AC signals The phase angle When the phase angle is 0 degrees, the maximum value of x(t) occurs at the second pulse moment; When it is -90 degrees, the positive zero crossing is synchronized with the second pulse.

[0128] Figure 6 It is the basic algorithm model of synchronous phasor measurement, including analog low-pass filter, synchronous sampling, DFT calculation, digital filtering and other links to complete phasor acquisition.

[0129] The device uses dynamic phasor fast software algorithm to calculate the AC voltage, AC current, sequence component amplitude, phase angle, channel frequency and frequency change rate, with high measurement accuracy and fast dynamic response performance.

[0130] The distribution network terminal sends the device information to the main station via 4G at a frequency of one minute (sending every second). The specific frame format includes:

[0131] The format of the message sent is as follows:

[0132]

[0133]

[0134] The SOC chip in this implementation scheme is a dual-core ARM architecture. In terms of software function division, one core is used as a management core, running the Linux operating system and performing tasks scheduling, configuration analysis, communication, display and other functions; the other core is used as a computing core, running naked, and performing computing tasks with high real-time requirements, such as sampling, calculation, logic processing, action export, etc.

[0135] In the hardware platform, each plug-in interrupt is generated by the plug-in FPGA. The interrupt cycle is generally configured by the application. The interrupt generation and synchronization process of each board is shown in Figure 7 .

[0136] For sampling, the application configures the FPGA and sets the relative time T1 (usually a value in units of 10ns) between the sampled CVT signal and a certain interrupt signal. Then the FPGA will give a CVT signal T1 after the interrupt signal is generated. T1 is related to the conversion time of the ADC and the time it takes for the FPGA to read the ADC data.

[0137] The ADC sampling cycle is exactly the same as the interrupt cycle of the processing protection logic, so only one interrupt is required. The application sets the relationship between sampling and interrupt;

[0138] For the ADC interface, the ADC conversion starts with the use of the CNVT signal, which is provided by the FPGA. The CNVT generation time is a certain time difference dt after INT1. After the ADC model is selected, its conversion time and data transmission time are fixed, so the time is set by the system program. The ADC data interface is an SPI interface. Since the multiple channels inside one ADC are asynchronously sampled, in order to ensure that the phase difference between the multiple ADC sampling channels is minimized, the corresponding channels between the multiple ADCs need to be synchronized. At this time, the FPGA needs to provide an SPI interface for each ADC, and these SPI interfaces can be executed in parallel and synchronously. After the FPGA reads the ADC results, consider providing a 2-level RAM cache.

[0139] As a specific embodiment, Figure 8This is a partial diagram of a city distribution network, from the substation outlet switch (1#) through the transmission line switch (2#), and to the ring network box DTU (3#), the 3# ring network box is connected to the transmission line to the 4# switch. The 3# ring network box provides power to the lower load of this station, and at the same time forms a contact switch relationship with an outlet switch of the 7# ring network box (according to the current power operation regulations, the principle of "ring network design, open loop operation" is adopted). The 4# switch is connected to the 5# ring network box, and the 5# ring network box is also connected to the overhead line to the 6# switch.

[0140] For the feeder terminal FTU associated with the overhead line switch, its network connection relationship is very simple, which is a "one-in, one-out" series connection relationship. For the ring network box DTU, it not only undertakes the continued transmission of power to the downstream (horizontal level), but also provides power support for the lower-level loads of this station; and it may serve as a contact switch for other distribution networks (such as the outgoing switch 1 of 3#DTU, which is the contact switch of 7# ring network box DTU).

[0141] exist Figure 8 The intelligent terminal devices (FTU, DTU) of all key nodes send the geographical location information of the equipment (equivalent to the switch information in the power topology) to the main station. The main station can preliminarily locate the site information of the equipment based on the basic geographic information system (GIS, Geo-Information System).

[0142] The master station system defines the possible electrical communication radius based on the geographic information of GNSS and the physical constraints of the electrical connection.

[0143] Take the 5# terminal DTU as an example for analysis. According to the geographic information, the geographical scanning radius is defined, and the associated intelligent devices and corresponding electrical switches (or station buildings) within the geographical radius are scanned. Fig. 9 The division of the network radius varies greatly due to the different grid structures and power supply densities in different regions. Power management personnel in each region can flexibly set the appropriate scanning radius according to the characteristics of their own power grids.

[0144] As shown in the figure, 5#DTU has a typical "two-input and four-output" switch configuration. Therefore, when it does not serve as a connecting switch for the lower switch, its main task of topology identification is to identify the connection relationship between the "two-input" switches 1 and 2.

[0145] The blue sector area includes the electrical nodes associated with the specified geographic radius - 4#, 6#, 9# and 10#. They can be considered as the electrical nodes that may be electrically related to the 5# ring main unit, preliminarily identified based on the initial screening results of GNSS geographic information.

[0146] The logic diagram of the master station's association relationship recognition based on geographic information is as follows: Fig.10 As shown;

[0147] Since each distribution network terminal is based on synchronous sampling of the GNSS absolute clock, the calculated electrical quantity is a synchronous phasor with an absolute time scale, which contains the amplitude and phase information of the electrical quantity.

[0148] Based on the possible electrical equipment identified by the GNSS correlation information, the master station can further accurately determine the electrical correlation through the electrical synchronous phasor measurement information sent by each terminal.

[0149] The basic criterion is: if the vector difference between the synchronized phasor of the target switch Breaker1 and the synchronized phasor of a switch Break2 within the associated radius is less than a specified parameter, Break2 is determined to be a lower-level associated branch of the target switch Break1.

[0150] |Vector1-Vector2|<ε

[0151] Among them, ε is a set parameter, which in principle shall not exceed 5% of the rated electrical quantity;

[0152] There is a preset condition that conforms to the actual distribution network, that is, the 10kV voltage level of the distribution network is low, and the capacitive current of the overhead line and the underground cable has a negligible effect on the shunting effect of the switches on both sides. It is assumed that the switch currents at both ends of the transmission line satisfy Kirchhoff's current law.

[0153] Based on the geographical information recognition of each terminal (corresponding electrical switch), the master station completes the topological relationship recognition based on the association relationship of the synchronized phasors in this stage. The logic block diagram is as follows: Fig.11 As shown;

[0154] The discrimination logic of the ring main unit terminal DTU is divided into incoming switch discrimination, outgoing switch discrimination, and possible lower-level contact switch discrimination. Each discrimination is similar to the discrimination logic of the FTU in the above figure.

[0155] like Fig.12 As shown, taking the 5# ring main unit node as an example, the 5#DTU is divided into an incoming switch 1 and an outgoing switch 1. By traversing the relevant nodes of the location information association library (including 4#, 6#, 9#, and 10#), it is easy to know that the incoming switch 1 of the 5# ring main unit and the 4#FTU form an electrical association relationship, and according to the power direction, it is determined that the 4#FTU is the upstream of the 5# ring main unit; similarly, it can be determined that the 6#FTU is the downstream of the 5# ring main unit.

[0156] The master station compares the amplitude and phase (mainly current) of the synchronous vector measurement data sent by each intelligent terminal device, and can find out that the incoming switch of 5#DTU has a direct electrical connection with the switch corresponding to 4#FTU, and the outgoing switch of 5#DTU has a direct electrical connection with the switch corresponding to 6#FTU; but there is no electrical connection with 9# and 10# distribution equipment (points); in addition, as an additional function, the master station can complete real-time monitoring of changes in the electrical topology of the distribution network based on the electrical characteristics of the ring network cabinet contact switch, and provide real-time electrical correlation information for the protection and control function.

[0157] As a specific implementation example, this solution has been piloted in the Jiangsu Huai'an Ecological Culture and Tourism Intelligent Connection Pilot Zone Demonstration Project. Without the intervention of the master station management personnel, the master station can automatically identify the topological connection relationship of 10kV lines and ring network boxes based on the GNSS positioning information and electrical associations of each distribution network terminal, greatly improving the work efficiency of the management department and providing basic technical conditions for regional differential distribution of the distribution network.

[0158] Ring network 1 consists of 10kV Qiushi D15 line and 10kV Jingyuan D14 line (powered by 10kV I-section busbar of Banzha transformer, which can be operated in a ring). D15 outgoing line—D1501 ring network cabinet—D1509 ring network cabinet—D1512 ring network cabinet—D1412 ring network cabinet—D1411 ring network cabinet—D1410 ring network cabinet—D1403 ring network cabinet—D1401 ring network cabinet—D14 outgoing line, forming a ring network. New cables need to be laid between D1512 ring network cabinet and D1412 ring network cabinet to form a ring network.

[0159] Ring network 2 is composed of 10kV Yunlin D41 line and 10kV Jinghui D42 line (powered by 10kV IV busbar of Banzha transformer, which can be operated in a closed ring). D41 outgoing line - D4101 ring network cabinet - D4105 ring network cabinet - D4106 ring network cabinet - D4205 ring network cabinet - D4204 ring network cabinet - D4201 ring network cabinet - D42 outgoing line constitutes a ring network.

[0160] New cables need to be laid between the D4106 ring main unit and the D4205 ring main unit to form a ring network.

[0161] New cables need to be laid between ring network 1 and ring network 2 to form a connecting line. (Between D1501 ring network cabinet and D4101 ring network cabinet)

[0162] The modified line framework is as follows Fig.13 As shown:

[0163] The ring main units involved in this project are: D1501 ring main unit, D1509 ring main unit, D1512 ring main unit, D1412 ring main unit, D1410 ring main unit, D4101 ring main unit, D4106 ring main unit, D4205 ring main unit, D4204 ring main unit, and D4201 ring main unit.

[0164] As a specific embodiment, a topology identification system based on GNSS and synchronized phasors includes:

[0165] A time synchronization module, which includes a GNSS receiver submodule and a time synchronization control submodule, which are respectively responsible for receiving and parsing GNSS signals to obtain accurate time synchronization signals and for distributing synchronization signals to all devices and modules in the system;

[0166] The data acquisition module includes a hardware control submodule and an ADC submodule. The hardware control submodule is responsible for controlling the ADC and performing data sampling at a specified sampling rate; the ADC submodule is responsible for converting analog signals into digital signals;

[0167] The data processing module is responsible for processing the sampled data, executing the phasor measurement algorithm, and obtaining the synchronized phasor data.

[0168] The multi-core processing module includes a management core module and a real-time computing core module. The management core module is responsible for management tasks such as task scheduling, configuration analysis, and communication. The real-time computing core module is responsible for executing real-time computing tasks such as data analysis, error detection and correction, etc.

[0169] The data upload module is responsible for uploading the processed synchronized phasor data to the master control station through the network;

[0170] The preliminary topology recognition module is responsible for processing the received GNSS information and performing preliminary topology recognition;

[0171] A refined topology identification module is used to further determine the real-time topology of the power grid using synchronized phasor data and to identify the actual connection relationship between electrical equipment;

[0172] The topology information update module is responsible for updating the identified topology information to the master station system.

[0173] The above specific implementations are only descriptions of the preferred implementations of the present invention, and do not limit the protection scope of the present invention. Without departing from the design concept and spirit of the present invention, various modifications, substitutions and improvements made by ordinary technicians in this field to the technical solution of the present invention based on the text description and drawings provided by the present invention should all fall within the protection scope of the present invention. The protection scope of the present invention is determined by the claims.

Claims

1. A topology identification method based on GNSS and synchronized phasors, characterized in that: include: Step S1: Obtaining a time synchronization signal through the Global Navigation Satellite System, i.e., GNSS, to ensure that all devices in the system can operate under the same time reference; Step S2: using a hardware controller to control the analog-to-digital converter to perform data sampling according to a specified sampling rate and sampling time; Step S3: In the control terminal, the sampled data is processed by software, a synchronized phasor measurement algorithm is executed, and synchronized phasor data is obtained; Step S4: In a multi-core processor architecture, one core is responsible for management tasks and another core is responsible for real-time computing tasks; perform data processing tasks; upload the processed synchrophasor data to the master control station through the network for further analysis and monitoring; Step S5: The master station receives the synchronized phasor data and GNSS information sent from the distribution network terminal, and performs preliminary topology recognition based on the received GNSS information to determine possible electrical connection relationships and device locations. The preliminary recognition steps are as follows: The node terminal device sends the geographical location information to the main station, and the main station receives the location information of all terminal devices in the jurisdiction; then, taking each terminal device as the object device, traverse the location information of nodes other than the object device, calculate the physical distance between the two, and determine whether the physical distance is less than the predetermined electrical radius. If the condition is met, the node is included in the associated node library of the object device node. If the physical distance does not meet the condition, the node is not included in the associated node library; after the traversal process is completed, the entire preliminary location identification process ends; Step S6: Use the synchronized phasor data to further identify the topology, determine the real-time topology of the power grid, and identify the actual connection relationship between electrical devices; further topology identification is as follows: The master station system first obtains the time-synchronized phasor data of the feeder terminal unit and searches the database for the location information associated node of the corresponding terminal unit; Different processing is performed according to the type of terminal unit: for the distribution terminal unit object, the system first determines the incoming or outgoing switch of the distribution terminal unit object; for the feeder terminal unit object, it directly enters the phase comparison step; The system checks the phasor relationship in the position association library to determine whether the synchronous vector phasor difference meets the preset conditions: |Vector1-Vector2|≤ε; If the phasor difference meets the conditions, the system enters the electrical connection information of the current terminal unit into the electrical connection database, and the process loops to judge the phasor relationship until all associated switches or nodes are traversed, and finally the position further identification process is completed; Step S7: Update the identified topology information to the master station system to provide real-time and accurate power grid topology information for subsequent monitoring and control.

2. A topology identification method based on GNSS and synchronized phasors according to claim 1, characterized in that: Step S1 includes: Step S11: configuring and starting the GNSS receiver to receive a time synchronization signal from the GNSS; Step S12: Analyze the GNSS signal to obtain accurate time information, and set the time information as the time base of the system; Step S13: Propagate the time synchronization signal to all devices in the system to ensure that all devices can operate under the same time reference.

3. The topology identification method based on GNSS and synchronized phasors according to claim 1, characterized in that: Step S3 includes: Step S31: In the control terminal, implement the phasor measurement algorithm and prepare to process the sampled data; Step S32: using the implemented algorithm to process the sampled data and obtain synchronized phasor data; Step S33: verify the acquired synchronized phasor data to ensure the accuracy and integrity of the data.

4. The topology identification method based on GNSS and synchronized phasors according to claim 1, characterized in that: Step S4 includes: Step S41: In a multi-core processor architecture, core tasks are configured and allocated, with one core responsible for management tasks and another core responsible for real-time computing tasks; Step S42: executing the data processing task in the designated core; Step S43: uploading the processed synchrophasor data to the master control station via the network for further analysis and monitoring; Step S44: confirm that the data has been successfully uploaded to the master control station and provide feedback on the upload status.

5. The topology identification method based on GNSS and synchronized phasors according to claim 3 is characterized in that: Step S5 includes: Step S51: the master station receives the synchronized phasor data and GNSS information sent by the distribution network terminal through the network; Step S52: Verify the integrity and accuracy of the received data to ensure that the data is not lost or damaged during transmission; Step S53: performing preprocessing operations on the received data to prepare for further topology identification; Step S54: using the received GNSS information, performing preliminary identification of electrical equipment locations and connection relationships, and constructing a preliminary topology model; Step S55: Determine possible electrical connection relationships and potential electrical contact points based on geographic information and basic properties of electrical equipment.

6. The topology identification method based on GNSS and synchronized phasors according to claim 1, characterized in that: Step S6 includes: Step S61: using the amplitude and phase information of the synchronized phasor data to further analyze the actual connection relationship between the electrical devices; Step S62: Determine the actual electrical connection status between the devices by comparing the phasor data between different devices; Step S63: According to the results of the phasor data analysis, the initially identified topology model is optimized and corrected to obtain the power grid topology structure.

7. The topology identification method based on GNSS and synchronized phasors according to claim 1, characterized in that: Step S7 comprises: Step S71: updating the result of fine topology identification to the topology database of the master station to ensure the real-time accuracy of the topology information; Step S72: Save the identified topology information in a database and perform a backup operation to prevent data loss or damage; Step S73: When a change in the grid topology is detected, the relevant monitoring and control systems are notified in a timely manner to ensure the accuracy and safety of system operation.

8. The topology identification method based on GNSS and synchronized phasors according to claim 1, characterized in that: It also includes data quality assessment and anomaly detection, as follows: Step S81: designing a data quality assessment standard to assess the quality of the collected synchronized phasor data; Step S82: monitor data quality in real time and send an alarm when data quality deteriorates; Step S83: Construct an anomaly detection model as follows: [s(x,n)=2^{-left(frac{E(h(x))}{c(n)}right)}] Where: (x) is a data point; (n) is the sample size; (E(h(x))) is the average path length of a data point (x) in all trees; (c(n)) is a correction factor, which is usually used to adjust the range of anomaly scores.

9. A topology identification system based on GNSS and synchronized phasors, applicable to the topology identification method based on GNSS and synchronized phasors described in claims 1-8, characterized in that: include: A time synchronization module, which includes a GNSS receiver submodule and a time synchronization control submodule, which are respectively responsible for receiving and parsing GNSS signals to obtain accurate time synchronization signals and for distributing synchronization signals to all devices and modules in the system; The data acquisition module includes a hardware control submodule and an ADC submodule. The hardware control submodule is responsible for controlling the ADC and performing data sampling at a specified sampling rate; the ADC submodule is responsible for converting analog signals into digital signals; The data processing module is responsible for processing the sampled data, executing the phasor measurement algorithm, and obtaining the synchronized phasor data; The multi-core processing module includes a management core module and a real-time computing core module. The management core module is responsible for management tasks such as task scheduling, configuration analysis, and communication. The real-time computing core module is responsible for executing real-time computing tasks, such as data analysis, error detection and correction, etc. The data upload module is responsible for uploading the processed synchrophasor data to the master control station through the network; The preliminary topology recognition module is responsible for processing the received GNSS information and performing preliminary topology recognition; A refined topology identification module is used to further determine the real-time topology of the power grid using synchronized phasor data and to identify the actual connection relationship between electrical equipment; The topology information update module is responsible for updating the identified topology information to the master station system.

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