A flexible direct-current converter station fault automatic diagnosis method and system

Abstract

The application discloses a kind of flexible direct current converter station fault automatic diagnosis method and system, method includes: when the system alarm or tripping is caused by the fault in the flexible direct current converter station station, by collecting monitoring background SER message, fault waveform, and automatically analyzing fault waveform, the fault position and fault type information are obtained, the application realizes the rapid analysis, positioning and auxiliary decision of direct current fault, provides effective technical support for relay protection professional, operating personnel and dispatch personnel, further improves the timeliness, accuracy and reliability of flexible direct current converter station fault judgment and disposal.

Description

Technical Field

[0001] This invention relates to the technical field of fault diagnosis for flexible DC converter stations, and in particular to an automatic fault diagnosis method and system for flexible DC converter stations. Background Technology

[0002] Currently, fault location within flexible DC converter stations primarily relies on specialized teams to collect and analyze fault information. DC systems exhibit numerous fault types and complex operating modes. When a grid fault occurs, a flood of alarm events occurs, requiring the extraction of crucial information from massive amounts of data. This reliance on the technical expertise of specialized teams leads to significant maintenance challenges and low fault location efficiency. Furthermore, current DC system fault waveform analysis cannot automatically collect, filter, organize, and analyze faults through technical means, thus imposing a heavy workload on team members. Summary of the Invention

[0003] The purpose of this invention is to overcome the shortcomings of the prior art and provide an automatic fault diagnosis method for flexible DC converter stations.

[0004] To achieve the above objectives, the technical solution provided by this invention is: an automatic fault diagnosis method for flexible DC converter stations, comprising:

[0005] Collect SER messages from the monitoring backend when a flexible DC converter station trips due to a fault, and extract key protection action information;

[0006] Collect the action time waveforms of the devices inside the flexible DC converter station when a fault trip occurs. These action time waveforms include electrical and switching quantity information of each area required by the flexible DC converter station.

[0007] Analyze the correspondence between the operating status, fault type, fault location and the protection action name in the key protection action information of the flexible DC converter station, and establish a DC protection fault database;

[0008] Based on the DC protection fault database, all possible fault areas and types are initially screened using the protection action names;

[0009] The electrical quantities used for analysis are selected based on the fault location and fault type.

[0010] Establish a waveform feature library for different types of faults in various areas of the flexible DC converter station;

[0011] The selected electrical quantities are analyzed and compared with the fault characteristics set in the waveform feature library. When all the set fault characteristics are met, the fault location and fault type are output.

[0012] Based on the electrical and switching information of the waveform before and after the fault, the system automatically generates a comparison chart of the operating status before and after the fault. At the same time, based on the determined fault location and fault type information, the system automatically generates an analysis report according to the template.

[0013] Furthermore, after collecting the SER messages from the monitoring backend when the flexible DC converter station trips due to a fault, the extracted key protection action information is arranged in chronological order.

[0014] Furthermore, the waveforms of the DC fault recording device, DC control and protection device, and valve control device at the time of the tripping of the flexible DC converter station are collected.

[0015] Furthermore, the established DC protection fault database includes the operating status of different flexible DC converter stations and the correspondence between fault types and protection action names in different fault areas.

[0016] Furthermore, the electrical quantities selected for analysis based on fault location and fault type specifically include:

[0017] The possible changes of various electrical quantities when a fault of a certain type occurs at a specific location are analyzed through theoretical analysis, RTDS real-time simulation experiments, or PSCAD offline simulation experiments; the electrical quantities with the most obvious changes and that best reflect the location and type of the fault are selected.

[0018] Furthermore, establishing waveform feature libraries for different types of faults in each region specifically includes:

[0019] Through theoretical analysis, RTDS real-time simulation experiments, or PSCAD offline simulation experiments, combined with specific AC / DC protection configurations, the fault characteristics of various types in each area are analyzed, and the changes in the corresponding electrical quantities are expressed mathematically. The recorded electrical quantities and mathematical expressions constitute the established waveform characteristics. Corresponding waveform characteristics are established for various types of faults at various locations. A large amount of waveform characteristic data from different locations and types are merged into one space for storage or recording, forming a waveform characteristic library.

[0020] Furthermore, the automatically generated operating status before and after the fault includes the connection status of the switch and disconnector, operating mode, power, voltage, and current.

[0021] To achieve the above objectives, the present invention further provides an automatic fault diagnosis system for flexible DC converter stations, comprising:

[0022] The information collection module is used to collect SER messages from the monitoring backend and the waveforms of the action times of the devices inside the flexible DC converter station;

[0023] The information extraction module is used to extract key protection action information from the SER messages in the monitoring backend;

[0024] The DC protection fault database establishment module is used to establish a DC protection fault database.

[0025] The preliminary screening module uses the name of the protection action to initially screen all possible fault areas and types from the DC protection fault database;

[0026] The electrical quantity screening module is used to filter electrical quantities for analysis based on fault location and fault type.

[0027] The waveform feature library creation module is used to create waveform feature libraries for different types of faults in various areas of the flexible DC converter station.

[0028] The analysis module is used to analyze the selected electrical quantities and compare them with the fault characteristics set in the waveform feature library. When all the set fault characteristics are met, the fault location and fault type are output.

[0029] The comparison module is used to automatically generate a comparison diagram of the operating status before and after the fault based on the electrical and switching information of the waveform before and after the fault at the moment of action.

[0030] The analysis report generation module is used to automatically generate analysis reports according to a template based on the determined fault location and fault type information.

[0031] The beneficial effects of implementing this invention are as follows:

[0032] When a fault occurs within the flexible DC converter station, causing a system alarm or trip, the system collects SER messages and fault waveforms from the monitoring backend and automatically analyzes the fault waveforms to determine the fault location and type. This enables rapid analysis, location, and decision support for DC faults, providing effective technical support for relay protection professionals, operators, and dispatchers, and further improving the timeliness, accuracy, and reliability of fault diagnosis and handling in flexible DC converter stations. Attached Figure Description

[0033] Figure 1 This is a flowchart illustrating the principle of an automatic fault diagnosis method for a flexible DC converter station according to the present invention.

[0034] Figure 2 This is a schematic diagram of the central channel flexible DC converter station;

[0035] Figure 3 A schematic diagram for selecting electrical quantities to be used for analysis;

[0036] Figure 4 This is a connection block diagram of an automatic fault diagnosis system for a flexible DC converter station according to the present invention. Detailed Implementation

[0037] The present invention will be further described below with reference to specific embodiments:

[0038] like Figure 1 As shown in the figure, this embodiment provides an automatic fault diagnosis method for flexible DC converter stations, including the following steps:

[0039] S1. Collect SER messages from the monitoring background when the flexible DC converter station trips due to a fault, and extract key protection action information. The extracted key protection action information is then arranged in chronological order.

[0040] S2. Collect the action time waveforms of the DC fault recording device, DC control and protection device and valve control device when the flexible DC converter station trips due to a fault. The action time waveforms include electrical and switching information of each area required by the flexible DC converter station.

[0041] S3. Analyze the correspondence between the operating status, fault type, fault location and the protection action name in the key protection action information of the flexible DC converter station, and establish a DC protection fault database.

[0042] S4. Based on the DC protection fault database, use the protection action name to initially screen out all possible fault areas and types;

[0043] S5. Select the electrical quantities to be analyzed based on the fault location and fault type;

[0044] S6. Establish a waveform feature library for different types of faults in various areas of the flexible DC converter station;

[0045] S7. Analyze the selected electrical quantities and compare them with the fault characteristics set in the waveform feature library. If all the set fault characteristics are met, output the fault location and fault type.

[0046] S8. Based on the electrical and switching quantity information of the waveform before and after the fault, automatically generate a comparison chart of the operating status before and after the fault. At the same time, based on the determined fault location and fault type information, automatically generate an analysis report according to the template. The automatically generated operating status before and after the fault includes the connection status of the switch and disconnector, the operating mode, power, voltage, and current.

[0047] To demonstrate the effectiveness of the method described in this embodiment, the implementation process of the method will be illustrated below using a medium-channel flexible DC converter station as an example:

[0048] (1) First, number the fault locations in each area of ​​the converter station according to the possible fault areas, such as... Figure 2 F3 to F14 represent grounding faults or open circuit faults at different locations. When various types of faults such as short circuits, grounding, and open circuits occur in the flexible DC converter station, the monitoring backend SER message will report the protection action information.

[0049] (2) Select key information from the protection action messages, mainly the name of the protection action, such as selecting information such as "XXXX protection action" from a large number of SER messages.

[0050] (3) Collect the action time waveforms of the DC fault recording device, DC control and protection device and valve control device when the flexible DC converter station trips due to a fault. The action time waveforms include electrical quantity and switching quantity information of each area required by the flexible DC converter station.

[0051] (4) Analyze the correspondence between the operating status, fault type, fault location and the protection action name in the key protection action information of the flexible DC converter station, and establish a DC protection fault database; for example, when the HVDC is running, when the "in-station grounding overcurrent protection action" occurs, the possible fault locations and fault types are analyzed as follows: F3 single-phase grounding, F5 single-phase grounding, F7 single-phase grounding, F8 single-phase grounding, F10 grounding, F11 grounding, and F12 grounding faults;

[0052] (5) Based on the DC protection fault database, all possible fault areas and types are initially screened out by the name of the protection action;

[0053] (6) Select electrical quantities for analysis based on fault location and fault type; for example, for a single-phase ground fault (F3), select valve-side voltage UVC, substation grounding current IACZ, valve-side current IVC, converter transformer-side current IVT, DC positive line voltage UDP, and DC negative line voltage UDN as analog quantities for analysis; select converter valve unlocking / locking status, substation grounding overcurrent protection operation status, grid-side switch opening / closing status, and valve-side switch opening / closing status as digital quantities for analysis; such as Figure 3 The system automatically selects the electrical quantities to be analyzed.

[0054] (7) Establish a waveform feature library for different types of faults in various areas of the flexible DC converter station;

[0055] Establishing waveform feature libraries for different types of faults in various regions specifically includes:

[0056] Through theoretical analysis, RTDS real-time simulation experiments, or PSCAD offline simulation experiments, combined with specific AC / DC protection configurations, the fault characteristics of various types in each area are analyzed, and the changes in the corresponding electrical quantities are expressed mathematically. The recorded electrical quantities and mathematical expressions constitute the established waveform characteristics. Corresponding waveform characteristics are established for various types of faults at various locations. A large amount of waveform characteristic data from different locations and types are merged into one space for storage or recording, forming a waveform characteristic library.

[0057] (8) Analyze the selected electrical quantities and compare them with the F3 fault characteristics set in the waveform feature library. If they meet the F3 fault characteristics, they are located as F3 faults. If they do not meet the F3 fault characteristics, select electrical quantities according to F5 faults and compare them with the set F5 fault characteristics. If they meet the F5 fault characteristics, they are located as F5 faults. If they do not meet the F5 fault characteristics, continue to the next step and select electrical quantities according to F7 faults until the fault location is found.

[0058] The characteristics of a single-phase ground fault (F3) are:

[0059] a. After a fault, the valve-side voltage UV of the faulty phase A is 0, and the voltage amplitude of the non-faulty phase rises to the line voltage amplitude.

[0060] b. When a ground fault occurs between IVC and IVT, there will be a differential current, meaning the sum of IVC and IVT will not be zero. Due to the presence of the neutral point grounding resistance (5kΩ) on the valve side, the differential current is very small, and the fault characteristics are not obvious.

[0061] c. The neutral point current IACZ on the valve side of the converter transformer exhibits sinusoidal fluctuations, with the maximum amplitude being the valve side phase voltage amplitude / neutral point impedance.

[0062] d. The pole-to-ground voltage fluctuates, and the fluctuation is affected by the valve-side voltage. Due to the fluctuation of the pole-to-ground voltage, the unbalanced voltage also increases accordingly during the fault.

[0063] e. If the effective value of the neutral point current IACZ_RMS on both valve sides exceeds 20A, the substation grounding overcurrent protection (76SG) will activate 10ms later.

[0064] f. When the converter valve is locked and the grid-side and valve-side switches are not yet separated, since the fault point is between IVT and IVC, IVC becomes 0 because there is no fault circuit, and IVT can be injected with fault current from the AC side, so IVT is not 0.

[0065] (9) If the fault location is not found after all possibilities have been checked, the result is output according to the fault location with the highest probability. The fault probabilities are sorted according to the number of fault features that are satisfied. The more fault features that are satisfied, the greater the probability.

[0066] (10) Analyze the fault waveform, read the system operating status before and after the fault, including the connection status of the switch and disconnector, the system operating mode, power level, etc., and visualize it to realize the comparison of the operating status before and after the fault and realize the fault backtracking function.

[0067] (11) Automatically generate fault reports according to the template, and display fault waveforms and key SER messages.

[0068] The aforementioned fault areas can be divided into AC protection zone, converter transformer protection zone, AC connection line protection zone, converter protection zone, and DC pole protection zone; the operation mode of the flexible DC converter station is divided into charging period and operation period.

[0069] In addition, this embodiment also discloses an automatic fault diagnosis system for flexible DC converter stations to implement the above method, such as... Figure 4 As shown, the system includes:

[0070] The information collection module is used to collect SER messages from the monitoring backend and the waveforms of the action times of the devices inside the flexible DC converter station;

[0071] The information extraction module is used to extract key protection action information from the SER messages in the monitoring backend;

[0072] The DC protection fault database establishment module is used to establish a DC protection fault database.

[0073] The preliminary screening module uses the name of the protection action to initially screen all possible fault areas and types from the DC protection fault database;

[0074] The electrical quantity screening module is used to filter electrical quantities for analysis based on fault location and fault type.

[0075] The waveform feature library creation module is used to create waveform feature libraries for different types of faults in various areas of the flexible DC converter station.

[0076] The analysis module is used to analyze the selected electrical quantities and compare them with the fault characteristics set in the waveform feature library. When all the set fault characteristics are met, the fault location and fault type are output.

[0077] The comparison module is used to automatically generate a comparison diagram of the operating status before and after the fault based on the electrical and switching information of the waveform before and after the fault at the moment of action.

[0078] The analysis report generation module is used to automatically generate analysis reports according to a template based on the determined fault location and fault type information.

[0079] In this embodiment, when a fault occurs within the flexible DC converter station, causing a system alarm or trip, the system collects SER messages and fault waveforms from the monitoring backend and automatically analyzes the fault waveforms to determine the fault location and type information. This enables rapid analysis, location, and decision support for DC faults, providing effective technical support for relay protection professionals, operators, and dispatchers, and further improving the timeliness, accuracy, and reliability of fault judgment and handling in flexible DC converter stations.

[0080] The above-described embodiments are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Therefore, any changes made in accordance with the shape and principle of the present invention should be covered within the protection scope of the present invention.

Claims

1. An automatic fault diagnosis method for a flexible DC converter station, characterized in that, include: Collect SER messages from the monitoring backend when a flexible DC converter station trips due to a fault, and extract key protection action information; Collect the waveforms of the actions of the devices inside the flexible DC converter station when a fault trip occurs. These waveforms include electrical and switching information for each area of ​​the flexible DC converter station. Each area includes the AC protection zone, converter transformer protection zone, AC connection line protection zone, converter protection zone, and DC pole protection zone. Analyze the correspondence between the operating status, fault type, fault location and the protection action name in the key protection action information of the flexible DC converter station, and establish a DC protection fault database; Based on the DC protection fault database, all possible fault areas and types are initially screened using the protection action names; The electrical quantities used for analysis are selected based on all possible areas and types of failures; Establish a waveform feature library for different types of faults in various areas of the flexible DC converter station; The selected electrical quantities are analyzed and compared with the fault characteristics set in the waveform feature library. When all the set fault characteristics are met, the fault location and fault type are output. If all possible faults have been checked and the fault location is still not found, the result is output as the fault location with the highest probability. Fault probabilities are sorted according to the number of fault features that are satisfied; the more fault features that are satisfied, the higher the probability. Based on the electrical and switching information of the waveform before and after the fault, the system automatically generates a comparison chart of the operating status before and after the fault. At the same time, based on the determined fault location and fault type information, the system automatically generates an analysis report according to the template.

2. The automatic fault diagnosis method for a flexible DC converter station according to claim 1, characterized in that, After collecting the SER messages from the monitoring backend when the flexible DC converter station trips due to a fault, the key protection action information extracted is arranged in chronological order.

3. The automatic fault diagnosis method for a flexible DC converter station according to claim 1, characterized in that, Collect waveforms of the operation of the DC fault recording device, DC control and protection device, and valve control device when the flexible DC converter station trips due to a fault.

4. The automatic fault diagnosis method for a flexible DC converter station according to claim 1, characterized in that, The established DC protection fault database includes the correspondence between different operating states of the flexible DC converter station and the names of various fault types and protection actions under different fault areas.

5. The automatic fault diagnosis method for a flexible DC converter station according to claim 1, characterized in that, The electrical quantities used for analysis are selected based on all possible fault areas and types, specifically including: The possible changes of various electrical quantities when a fault of a certain type occurs at a specific location are analyzed through theoretical analysis, RTDS real-time simulation experiments, or PSCAD offline simulation experiments; the electrical quantities with the most obvious changes and that best reflect the location and type of the fault are selected.

6. The automatic fault diagnosis method for a flexible DC converter station according to claim 1, characterized in that, Establishing waveform feature libraries for different types of faults in various regions specifically includes: Through theoretical analysis, RTDS real-time simulation experiments, or PSCAD offline simulation experiments, combined with specific AC / DC protection configurations, the fault characteristics of various types in each area are analyzed, and the changes in the corresponding electrical quantities are expressed mathematically. The recorded electrical quantities and mathematical expressions constitute the established waveform characteristics. Corresponding waveform characteristics are established for various types of faults at various locations. A large amount of waveform characteristic data from different locations and types are merged into one space for storage or recording, forming a waveform characteristic library.

7. The automatic fault diagnosis method for a flexible DC converter station according to claim 1, characterized in that, The automatically generated operating status before and after the fault includes the connection status of the switch and disconnector, operating mode, power, voltage, and current.

8. An automatic fault diagnosis system for a flexible DC converter station, characterized in that, include: The information collection module is used to collect SER messages from the monitoring backend and the waveforms of the action times of the devices inside the flexible DC converter station. The information extraction module is used to extract key protection action information from the SER messages in the monitoring backend; The DC protection fault database establishment module is used to establish a DC protection fault database. The preliminary screening module uses the name of the protection action to initially screen all possible fault areas and types from the DC protection fault database; The electrical quantity screening module is used to filter out electrical quantities for analysis based on all possible fault areas and types. The waveform feature library creation module is used to create waveform feature libraries for different types of faults in various areas of the flexible DC converter station; each area includes AC protection zone, converter transformer protection zone, AC connection line protection zone, converter protection zone, and DC pole protection zone. The analysis module is used to analyze the selected electrical quantities and compare them with the fault characteristics set in the waveform feature library. When all the set fault characteristics are met, the fault location and fault type are output. If all possible faults have been checked and the fault location is still not found, the result is output as the fault location with the highest probability. Fault probabilities are sorted according to the number of fault features that are satisfied; the more fault features that are satisfied, the higher the probability. The comparison module is used to automatically generate a comparison diagram of the operating status before and after the fault based on the electrical and switching information of the waveform before and after the fault at the moment of action. The analysis report generation module is used to automatically generate analysis reports according to a template based on the determined fault location and fault type information.

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