Active power distribution network fault traveling wave positioning and cascading fault protection system and method

Abstract

The invention provides an active power distribution network fault traveling wave positioning and cascading fault protection system, and the system comprises a distributed terminal collection module which is used for collecting the current, voltage, traveling wave signals and switch state information of a line in real time; the communication transmission module is used for transmitting the data acquired by the distributed terminal acquisition module to an information master station layer in real time by adopting multiple communication protocols; the information master station layer comprises a database, a fault studying and judging module and a human-computer interaction interface; wherein the database is used for storing real-time data, historical data and an accurate power distribution network line topological relation model; the fault studying and judging module is used for preprocessing data, preliminarily positioning traveling waves, fusing and verifying multi-source information and analyzing and actively protecting cascading fault risks; the man-machine interaction interface is used for displaying line topology, real-time data, fault positioning results, early warning information and disposal schemes recommended by the system. The method can achieve the precise and rapid positioning of faults, actively prevents cascading faults, and improves the toughness of a power distribution network.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of power systems, in particular to a kind of active distribution network fault traveling wave positioning and cascading failure protection system and method. BACKGROUND

[0002] With the large access of distributed power supply (DG), the traditional distribution network is gradually transformed into active distribution network, and its fault characteristics become more complex, which brings great challenges to the rapid and accurate positioning of fault. Quickly and accurately isolating fault and preventing fault expansion from causing cascading reaction is the key to guarantee the safe and stable operation of distribution network.

[0003] The existing fault positioning technology of distribution network mainly includes impedance method, traveling wave method and intelligent algorithm. Among them, the impedance method is simple in principle but is easily affected by system operation mode, distributed power supply and fault transition resistance, and has limited accuracy. The traveling wave method has high positioning accuracy, but its reliability depends on the accurate capture of high-frequency signals and time accuracy, and it is difficult to identify waveforms in complex branch lines. At the same time, the existing system mostly uses a single type of terminal (such as only fault indicator or only FTU) for monitoring, and the information dimension is single, which is difficult to cope with the complex fault scene of active distribution network. More importantly, the existing system mostly focuses on positioning and isolation after fault, lacks the ability of proactive analysis and active defense of cascading trip risk caused by fault, and cannot fundamentally curb the occurrence of large-area power outage accidents. SUMMARY

[0004] The purpose of the embodiment of the present application is to provide a kind of active distribution network fault traveling wave positioning and cascading failure protection system and method, which can realize the accurate and rapid positioning of fault, and actively prevent cascading failure, and improve the resilience of distribution network.

[0005] In order to achieve the above purpose, the embodiment of the present application provides an active distribution network fault traveling wave positioning and cascading failure protection system, which comprises: A distributed terminal acquisition module is used to acquire current, voltage, traveling wave signal and switch state information of line in real time, including traveling wave terminal, fault indicator terminal, distribution FTU terminal and distribution DTU terminal installed on the tower of overhead line of distribution network;Among them, the traveling wave terminal is used to accurately capture the transient voltage / current traveling wave signal generated by fault, and record the accurate UTC time of wave head arrival;The fault indicator terminal is used to detect the short-circuit and ground fault of line, and report the fault characteristic quantity of overcurrent and zero sequence current;The distribution FTU terminal is installed at the feeder switch, which is used to acquire analog quantity of current, voltage and power of switch and position state of opening and closing of switch;The distribution DTU terminal is installed in distribution room or switching station, which is used to monitor, protect and control key distribution equipment; The communication transmission module is used to transmit data collected by the distributed terminal acquisition module to the information master station layer in real time using multiple communication protocols. The main information station layer includes a database, a fault analysis module, and a human-machine interface. The database stores real-time data, historical data, and an accurate distribution network line topology model. The fault analysis module is used for data preprocessing, preliminary location of traveling waves, fusion and verification of multi-source information, and analysis and proactive protection against cascading fault risks. The human-machine interface displays line topology, real-time data, fault location results, early warning information, and system-recommended handling solutions.

[0006] Preferably, the communication transmission module supports multiple industry standard communication protocols, including MQTT for lightweight communication of IoT devices, IEC 60870-5-101 for serial communication, and IEC 60870-5-104 for network communication.

[0007] Preferably, the fault assessment module includes a data preprocessing unit, which performs time synchronization, format unification, and noise filtering on data from different terminals and different protocols to form a high-quality data pool with a unified time scale.

[0008] Preferably, the fault assessment module includes a traveling wave positioning unit, which is used to calculate the preliminary distance of the fault point based on the time difference and wave velocity of the wave front arriving at different traveling wave terminals using the principle of dual-end or multi-end traveling wave ranging.

[0009] Preferably, the fault analysis module further includes a multi-source information fusion analysis unit, which is used to perform correlation analysis and verification on the calculation results of the traveling wave positioning unit, the overcurrent and grounding information reported by the fault indicator terminal, and the switch change and protection action information reported by the FTU / DTU terminal, so as to correct the positioning results, determine the fault type and identify potential cascading fault risks.

[0010] Preferably, the cascading fault risk analysis and proactive protection includes, after fault location, the fault assessment module simulating the network topology changes after the fault trips and performing power flow calculation analysis to predict which lines will be overloaded due to power transfer and assess system stability; and once high-risk lines are identified, preventive control strategies are automatically generated and executed through the system interface.

[0011] Preferably, the automatically generated preventive control strategy includes regulating controllable distributed power sources, cutting off non-critical loads, and switching on / off reactive power compensation equipment.

[0012] On the other hand, the present invention provides a method for active distribution network fault traveling wave location and cascading fault protection, which uses the active distribution network fault traveling wave location and cascading fault protection system as described above for traveling wave location and fault protection.

[0013] Preferably, the method includes: The electrical quantities, traveling wave signals, and status data before and after a fault are collected synchronously using multiple terminals deployed at various nodes of the line. The collected data is uploaded to the main information station using multiple communication protocols; The main information station receives data and aligns and merges the data based on the pre-stored line topology. Based on the fused data, traveling wave ranging technology is used to perform preliminary fault location; By combining the fault characteristic information reported by the fault indicator, FTU, and DTU, the preliminary location results are verified and the location is precisely determined, and the fault type is identified. Based on the fault analysis results, alarm information is generated and sent to relevant systems and personnel; Based on the current fault status and network topology, a security and stability assessment is conducted. If there is a risk of cascading failures, preventative control instructions are generated and issued.

[0014] Preferably, the method further includes, after generating alarm information based on the fault assessment results and sending it to relevant systems and personnel, automatically generating UAV inspection work orders and target routes based on precise positioning information, and dispatching them for on-site confirmation.

[0015] According to the above technical solution, the system provided by this invention includes multiple traveling wave terminals, fault indicator terminals, distribution FTU terminals, and distribution DTU terminals deployed on overhead line towers of the distribution network, as well as an information master station located at the back end. Each terminal is responsible for collecting electrical quantities, traveling wave signals, and status data on the line, and uploading them to the information master station through multiple communication protocols. The information master station integrates the line topology relationship, performs fusion analysis using the multi-source heterogeneous data, accurately determines the fault type and fault location using a fault judgment algorithm, and generates early warning or control commands to notify relevant systems and maintenance personnel. This enables rapid and accurate isolation of distribution network line faults and proactive defense against cascading faults, greatly improving the reliability and security of the distribution network power supply.

[0016] Other features and advantages of the embodiments of the present invention will be described in detail in the following detailed description section. Attached Figure Description

[0017] The accompanying drawings are provided to further illustrate embodiments of the present invention and form part of the specification. They are used together with the following detailed description to explain the embodiments of the present invention, but do not constitute a limitation thereof. In the drawings: Figure 1 This is a flowchart of an active power distribution network fault traveling wave location and cascading fault protection method provided by the present invention. Detailed Implementation

[0018] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the scope of the present invention.

[0019] It should be noted that the acquisition, transmission, storage, use, and processing of data in the technical solution of this application all comply with relevant laws and regulations. In the embodiments of this application, certain existing industry solutions such as software, components, and models may be mentioned. These should be considered exemplary, intended only to illustrate the feasibility of implementing the technical solution of this application, and do not imply that the applicant has already used or necessarily used such solutions.

[0020] This invention provides an active power distribution network fault traveling wave location and cascading fault protection system, the system comprising: The distributed terminal acquisition module is used to acquire real-time current, voltage, traveling wave signals, and switch status information of the line. This includes traveling wave terminals, fault indicator terminals, distribution FTU terminals, and distribution DTU terminals installed on the towers of overhead lines in the distribution network. The traveling wave terminal accurately captures transient voltage / current traveling wave signals generated by faults and records the precise UTC time of wavefront arrival. The fault indicator terminal detects short-circuit and ground faults in the line and reports fault characteristics such as overcurrent and zero-sequence current. The distribution FTU terminal is installed at the feeder switch to acquire analog quantities of switch current, voltage, and power, as well as the switch's open / close position status. The distribution DTU terminal is installed in the substation or switching station to monitor, protect, and control critical power distribution equipment. The communication transmission module is used to transmit data collected by the distributed terminal acquisition module to the information master station layer in real time using multiple communication protocols. The main information station layer includes a database, a fault analysis module, and a human-machine interface. The database stores real-time data, historical data, and an accurate distribution network line topology model. The fault analysis module is used for data preprocessing, preliminary location of traveling waves, fusion and verification of multi-source information, and analysis and proactive protection against cascading fault risks. The human-machine interface displays line topology, real-time data, fault location results, early warning information, and system-recommended handling solutions.

[0021] Through the above technical solution, each terminal of the system is responsible for collecting electrical quantities, traveling wave signals, and status data on the lines, and uploading them to the information master station through multiple communication protocols. The information master station integrates the line topology relationship, performs fusion analysis using the multi-source heterogeneous data, employs fault judgment algorithms to accurately determine the fault type and location, and generates early warning or control commands to notify relevant systems and maintenance personnel. This enables rapid and accurate isolation of distribution network line faults and proactive defense against cascading faults, greatly improving the reliability and security of the distribution network power supply.

[0022] In this embodiment, the communication transmission module preferably supports multiple industry standard communication protocols, including MQTT for lightweight communication of IoT devices, IEC 60870-5-101 for serial communication, and IEC 60870-5-104 for network communication. In this way, the communication transmission module can adapt to the communication needs of different terminal devices and reliably and in real time transmit the data from the acquisition layer to the information master station.

[0023] In this embodiment, the fault assessment module includes a data preprocessing unit, which performs time synchronization, format unification, and noise filtering on data from different terminals and different protocols to form a high-quality data pool with a unified time scale.

[0024] Furthermore, in this active power distribution network fault traveling wave location and cascading fault protection system, the aforementioned fault analysis module also includes a traveling wave location unit, which is used to calculate the preliminary distance of the fault point based on the time difference and wave velocity of the wave front arriving at different traveling wave terminals using the principle of double-end or multi-end traveling wave ranging.

[0025] Furthermore, the aforementioned fault assessment module also includes a multi-source information fusion assessment unit, used to perform correlation analysis and verification between the calculation results of the traveling wave positioning unit and the overcurrent and grounding information reported by the fault indicator terminal, as well as the switch change and protection action information reported by the FTU / DTU terminal, in order to correct the positioning results, determine the fault type, and identify potential cascading fault risks. For example, if the traveling wave positioning point is located in a certain section, and the fault indicators at both ends of that section are activated, the correctness of the positioning result is verified. This process can effectively eliminate interference from traveling wave front identification, significantly improve positioning accuracy and reliability, and accurately determine the fault type (such as phase-to-phase short circuit, single-phase grounding, etc.).

[0026] In this embodiment, preferably, the above-mentioned cascading failure risk analysis and active protection includes, after fault location, the fault judgment module simulates the network topology changes after the fault trips and performs power flow calculation analysis to predict which lines will be overloaded due to power transfer and assess system stability; and once a high-risk line is identified, a preventive control strategy is automatically generated and executed through the system interface to nip cascading failures in the bud.

[0027] In this embodiment, preferably, the automatically generated preventive control strategy includes adjusting controllable distributed power sources, cutting off non-critical loads, and switching reactive power compensation equipment to proactively prevent cascading failures.

[0028] like Figure 1As shown, another aspect of the present invention provides a method for active power distribution network fault traveling wave location and cascading fault protection, which uses the above-mentioned active power distribution network fault traveling wave location and cascading fault protection system for traveling wave location and fault protection.

[0029] Specifically, the method includes: The electrical quantities, traveling wave signals, and status data before and after a fault are collected synchronously using multiple terminals deployed at various nodes of the line. The collected data is uploaded to the main information station using multiple communication protocols; The main information station receives data and aligns and merges the data based on the pre-stored line topology. Based on the fused data, traveling wave ranging technology is used to perform preliminary fault location; By combining the fault characteristic information reported by the fault indicator, FTU, and DTU, the preliminary location results are verified and the location is precisely determined, and the fault type is identified. Based on the fault analysis results, alarm information is generated and sent to relevant systems and personnel; Based on the current fault status and network topology, a security and stability assessment is conducted. If there is a risk of cascading failures, preventative control instructions are generated and issued.

[0030] Furthermore, in this embodiment, the preferred method further includes, after generating alarm information based on the fault assessment results and sending it to relevant systems and personnel, automatically generating a drone inspection work order and target route based on precise positioning information, and dispatching it for on-site confirmation. This significantly avoids response delays, reduces the time from fault occurrence to maintenance personnel arriving on-site for inspection and confirmation, and meets the requirements for high power supply reliability.

[0031] The following is a specific implementation method to illustrate the active power distribution network fault traveling wave location and cascading fault protection method provided by the present invention: First, on a 10kV distribution line, a traveling wave terminal and a fault indicator terminal are installed at regular intervals (e.g., 2 kilometers), an FTU is installed at each sectionalizing switch and tie switch, and a DTU is installed in the distribution room.

[0032] Secondly, when a permanent short-circuit fault occurs at some point on the line: 1. The high-frequency transient traveling wave signal generated at the fault point propagates along the line to both ends at near the speed of light. The traveling wave terminals along the line accurately record the arrival time of the wavefront (e.g., T1, T2, ... Tn) and report it to the information master station via the network using the IEC104 protocol; 2. The fault current causes the fault indicator terminal on the line to activate, reporting the overcurrent event and the direction of the fault current; 3. The protection switch (controlled by the FTU) near the fault point detects overcurrent and trips. The FTU reports the "protection action" and "switch position change" information through the 101 / 104 protocol. Next, after receiving this information, the main information station activates the fault analysis module. The specific process is as follows: First, the traveling wave positioning unit uses the timestamps of the two most recent traveling wave terminals ( and ), using formula (in, v For wave velocity, The preliminary location of fault point F is calculated for the total length of the line. Subsequently, the multi-source information fusion unit accessed the topology data and discovered that the initial location point F was between sectionalizing switches K1 and K2. Data analysis revealed that fault indicators FI1 and FI2 within this section both detected fault current pointing inwards, and FTU_K1 reported a protection trip signal. This high degree of consistency in the data confirmed that the fault point was indeed within this section, pinpointing the exact tower location calculated by the traveling wave, and classifying it as a phase-to-phase short-circuit fault.

[0033] The main station immediately generates a fault alarm and notifies maintenance personnel via SMS, dispatch screen, and other means, providing accurate faulty tower number and navigation information.

[0034] Simultaneously, the cascading fault analysis unit simulated the grid state after switch K1 tripped and calculated that the line containing tie switch K3 was at risk of overload due to the transfer of loads. The main station immediately sent instructions to the Distributed Energy Management System (DERMS) to slightly reduce the output of non-critical distributed photovoltaic power generation in the power supply area, and sent instructions to the load control system to prepare to start interruptible loads. These measures effectively prevented the tie line from tripping due to overload and prevented the power outage from expanding.

[0035] In summary, the system and method provided by this invention complement the advantages of the traveling wave method (high precision) and the conventional fault indication method (high reliability), and utilize multi-source information fusion verification to effectively overcome the limitations of a single method. It is particularly suitable for distribution networks with complex structures and distributed power sources. It achieves automated processes from data acquisition, transmission, analysis to decision-making, significantly shortening the time for fault detection, location, and isolation. Simultaneously, it breaks through the passive "post-event remediation" mode of traditional systems, adding forward-looking cascading fault risk prediction and active control functions, significantly improving the overall safety level and disaster prevention and mitigation capabilities of the distribution network. Furthermore, by employing multiple standard communication protocols, it is compatible with various existing terminal devices, facilitating future system expansion and upgrades.

[0036] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0037] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0038] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0039] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0040] In a typical configuration, a computing device includes one or more processors (CPU), input / output interfaces, network interfaces, and memory.

[0041] Memory may include non-persistent memory in computer-readable media, such as random access memory (RAM) and / or non-volatile memory, such as read-only memory (ROM) or flash RAM. Memory is an example of computer-readable media.

[0042] Computer-readable media includes both permanent and non-permanent, removable and non-removable media that can store information using any method or technology. Information can be computer-readable instructions, data structures, modules of programs, or other data. Examples of computer storage media include, but are not limited to, phase-change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technologies, CD-ROM, digital versatile optical disc (DVD) or other optical storage, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other non-transferable medium that can be used to store information accessible by a computing device. As defined herein, computer-readable media does not include transient computer-readable media, such as modulated data signals and carrier waves.

[0043] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0044] The above are merely embodiments of this application and are not intended to limit the scope of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of the claims of this application.

Claims

1. An active power distribution network fault traveling wave location and cascading failure protection system, characterized in that, The system comprises: a distributed terminal acquisition module for real-time acquisition of current, voltage, traveling wave signals and switch state information of a line, including a traveling wave terminal, a fault indicator terminal, a distribution FTU terminal and a distribution DTU terminal installed on a distribution network overhead line tower; wherein the traveling wave terminal is used for accurately capturing the transient voltage / current traveling wave signals generated by the fault and recording the accurate UTC time of the arrival of the wave head; the fault indicator terminal is used for detecting short circuit and ground fault of the line and reporting fault characteristic quantities of overcurrent and zero sequence current; the distribution FTU terminal is installed at the feeder switch and is used for acquiring analog quantities of current, voltage and power of the switch and the on-off position state of the switch; the distribution DTU terminal is installed in a distribution room or a switching station and is used for monitoring, protecting and controlling key distribution equipment; a communication transmission module for real-time transmission of data acquired by the distributed terminal acquisition module to an information master station layer using multiple communication protocols; the information master station layer comprises a database, a fault research and judgment module and a man-machine interface; wherein the database is used for storing real-time data, historical data and an accurate distribution network line topology relationship model; the fault research and judgment module is used for preprocessing data, preliminarily locating a traveling wave, fusing and checking multi-source information and analyzing and actively protecting cascading failure risks; and the man-machine interface is used for displaying line topology, real-time data, fault location results, early warning information and a system recommended treatment scheme.

2. The active power distribution network fault traveling wave location and cascading failure protection system of claim 1, wherein, The communication transmission module supports multiple industrial standard communication protocols, including MQTT for lightweight communication of Internet of Things devices, IEC 60870-5-101 for serial communication and IEC 60870-5-104 for network communication.

3. The active power distribution network fault traveling wave location and cascading failure protection system of claim 1, wherein, The fault research and judgment module comprises a data preprocessing unit for time synchronization, format unification and noise filtering of data from different terminals and different protocols to form a high-quality data pool with a unified time scale.

4. The active power distribution network fault traveling wave location and cascading failure protection system of claim 3, wherein, The fault research and judgment module comprises a traveling wave positioning unit for calculating a preliminary distance of a fault point according to a time difference of wave head arrival at different traveling wave terminals and a wave speed by using a double-end or multi-end traveling wave distance measurement principle.

5. The active power distribution network fault traveling wave location and cascading failure protection system of claim 4, wherein, The fault research and judgment module further comprises a multi-source information fusion research and judgment unit for correlation analysis and checking of overcurrent and grounding information reported by the fault indicator terminal and switch position change and protection action information reported by the FTU / DTU terminal based on a calculation result of the traveling wave positioning unit, so as to correct the positioning result, determine a fault type and identify a potential cascading failure risk.

6. The active power distribution network fault traveling wave location and cascading failure protection system of claim 5, wherein, The cascading failure risk analysis and active protection comprises, after fault location, simulation of network topology changes after tripping of the fault by the fault research and judgment module and calculation and analysis of power flow to predict which lines will be overloaded due to power transfer and evaluate system stability; and once a high-risk line is identified, a preventive control strategy is automatically generated and is executed through a system interface.

7. The active power distribution network fault traveling wave location and cascading failure protection system of claim 6, wherein, The automatically generated preventive control strategy comprises adjusting controllable distributed power sources, cutting off non-essential loads and switching reactive power compensation devices.

8. An active power distribution network fault traveling wave locating and cascading failure protection method, characterized in that, The method uses the active power distribution network fault traveling wave positioning and cascading failure protection system as claimed in any one of claims 1-7 to perform traveling wave positioning and fault protection.

9. The active power distribution network fault traveling wave locating and cascading failure protection method of claim 8, wherein, The method comprises: Synchronously collecting electrical quantities, traveling wave signals and state quantity data before and after the fault occurs by using a plurality of terminals deployed at each node of the line; Uploading the collected data to an information master station through a plurality of communication protocols; Using the information master station to receive the data and align and fuse the data according to the pre-stored line topological relationship; Based on the fused data, using a traveling wave distance measurement technology to perform preliminary positioning of the fault point; Combining the fault characteristic information reported by the fault indicators, FTUs and DTUs to verify and accurately position the preliminary positioning result and determine the fault type; According to the fault research and judgment result, generating an alarm information and delivering it to related systems and personnel; Based on the current fault state and network topology, performing safety and stability evaluation, and if there is a cascading failure risk, generating and delivering a preventive control instruction.

10. The active power distribution network fault traveling wave locating and cascading failure protection method of claim 9, wherein, The method further comprises, after generating the alarm information and delivering it to related systems and personnel according to the fault research and judgment result, automatically generating a UAV inspection work order and a targeted flight route based on the accurate positioning information, and dispatching execution of on-site confirmation.

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