Method and system for automatically identifying abnormity of secondary system of transformer substation

Abstract

The invention provides a method and a system for automatically identifying abnormity of a secondary system of a transformer substation. The method comprises the following steps: acquiring voltage and current monitoring data and recording data of secondary equipment; performing primary processing on the voltage and current monitoring data to obtain voltage and current data corresponding to primary equipment and secondary equipment; performing primary processing on the recording data, and extracting primary equipment information and corresponding voltage and current instantaneous value data; based on a steady-state anomaly identification criterion, carrying out steady-state anomaly identification on the voltage and current data, and sending an anomaly alarm to equipment meeting the steady-state anomaly identification criterion; and on the basis of a transient anomaly identification criterion, performing transient anomaly identification on the voltage and current instantaneous value data, and giving an anomaly alarm to a channel meeting the transient anomaly identification criterion. The problems that an existing secondary equipment and loop abnormity online identification method is high in data quality requirement and not high in abnormity identification accuracy, and which equipment is abnormal and which type is abnormal cannot be identified specifically are solved.

Description

Technical Field

[0001] The present invention relates to the field of online monitoring of secondary equipment in a substation, and in particular to an automatic identification method and system for abnormalities in a secondary system of a substation. Background Art

[0002] Substations are the transmission and transformation hubs of power systems. The secondary systems (secondary equipment and secondary circuits) in substations are responsible for information collection, real-time monitoring, operation control and fault isolation of primary equipment, and play a vital role in the safe and stable operation of power systems. Abnormalities in secondary equipment and circuits, especially sampling abnormalities, are important factors affecting the reliability of secondary systems. In mild cases, they will affect the correctness and accuracy of information collection, operation monitoring and control, and in severe cases, they may lead to miscontrol, misoperation or refusal of protection. Not only will it be impossible to correctly operate control or isolate faults, but it will also cause the scope of power outages to expand, which will have a serious impact on the safe and stable operation of the power system.

[0003] In recent years, with the large-scale construction of smart grids and smart substations, unmanned substations have become the main form of new substations. On the one hand, the dependence of power grid control, operation and management on automation systems has been continuously increasing, and higher requirements have been put forward for the online monitoring and intelligent operation and maintenance of the operating status of secondary equipment itself; on the other hand, various information of secondary equipment in substations can be obtained more conveniently. Not only is it more convenient to obtain secondary equipment control and action contact information, messages, recordings and other secondary equipment information of traditional substations, but also the sampling information, status information, control and action information of secondary equipment can be easily obtained remotely through the power communication network, providing a data basis for the application of online monitoring technology for secondary equipment.

[0004] The various secondary equipment and circuit anomaly identification methods currently proposed mainly focus on the comparison of two homologous data. They can find inconsistencies in homologous data, but do not identify which data is normal and which is abnormal, nor do they identify the specific type of abnormality. Due to the limitations of data acquisition quality, when homologous data is missing or the quality does not meet the requirements, homologous data comparison and anomaly identification cannot be achieved. Summary of the invention

[0005] In view of the above technical problems, the present invention provides a method and system for automatically identifying abnormalities in a secondary system of a substation, the method comprising:

[0006] Obtain voltage and current monitoring data and waveform data of secondary equipment;

[0007] Perform preliminary processing on the voltage and current monitoring data to obtain the voltage and current data corresponding to the primary equipment and the secondary equipment; perform preliminary processing on the recorded wave data to extract the primary equipment information and the corresponding voltage and current instantaneous value data;

[0008] Based on the steady-state abnormality identification criteria, steady-state abnormality identification is performed on the voltage and current data, and an abnormality alarm is issued for the equipment that meets the steady-state abnormality identification criteria; based on the transient abnormality identification criteria, transient abnormality identification is performed on the instantaneous value data of voltage and current, and an abnormality alarm is issued for the channel that meets the transient abnormality identification criteria.

[0009] Furthermore, the steady-state abnormality identification criteria include: three-phase voltage inconsistency, differential current exceeding the limit, and inconsistency of homologous data.

[0010] Furthermore, the transient abnormality identification criteria include: inconsistency between self-generated and external zero-sequence voltages, zero-sequence voltage exceeding a limit, zero-sequence current exceeding a limit, voltage harmonic exceeding a limit, current harmonic exceeding a limit, and inconsistency between homologous data.

[0011] Furthermore, homologous data refers to data belonging to the same primary device and the same time period.

[0012] Furthermore, it also includes:

[0013] After the abnormal alarm information is issued, the corresponding occurrence time, primary device name, secondary device name, and the reason or criterion for identifying the abnormality are given.

[0014] The present invention also provides an automatic identification system for abnormalities in a secondary system of a substation, comprising:

[0015] Data acquisition module, used to obtain voltage and current monitoring data and waveform data of secondary equipment;

[0016] The data preliminary processing module is used to perform preliminary processing on the voltage and current monitoring data to obtain the voltage and current data corresponding to the primary equipment and the secondary equipment; perform preliminary processing on the recorded wave data to extract the primary equipment information and the corresponding voltage and current instantaneous value data;

[0017] The abnormality identification module is used to identify steady-state abnormalities of the voltage and current data based on steady-state abnormality identification criteria, and issue abnormality alarms for devices that meet the steady-state abnormality identification criteria; based on transient abnormality identification criteria, it identifies transient abnormalities of the instantaneous value data of the voltage and current, and issues abnormality alarms for channels that meet the transient abnormality identification criteria.

[0018] Furthermore, the steady-state abnormality identification criteria include: three-phase voltage inconsistency, differential current exceeding the limit, and inconsistency of homologous data.

[0019] Furthermore, the transient abnormality identification criteria include: inconsistency between self-generated and external zero-sequence voltages, zero-sequence voltage exceeding a limit, zero-sequence current exceeding a limit, voltage harmonic exceeding a limit, current harmonic exceeding a limit, and inconsistency between homologous data.

[0020] Furthermore, homologous data refers to data belonging to the same primary device and the same time period.

[0021] Furthermore, it also includes:

[0022] The abnormal alarm module is used to issue abnormal alarm information, give the corresponding occurrence time, primary device name, secondary device name, and the cause or criterion for identifying the abnormality.

[0023] The present invention provides an automatic identification method and system for abnormalities in the secondary system of a substation. Based on the secondary system abnormality monitoring system, the voltage and current monitoring data and recording files (voltage and current sampling information of protection, measurement and control devices, etc., device recording or fault recording information) from the secondary equipment are first obtained; then the monitoring data and recording files are preliminarily processed to obtain the voltage and current data corresponding to the primary equipment and the secondary equipment, and the homologous data belonging to the same primary equipment are marked; for each group of voltage and current data, an abnormality discrimination method is applied for discrimination, and an alarm is issued for the secondary equipment or circuit with abnormality according to the discrimination result. The existing online identification method for abnormalities of secondary equipment and circuits solves the problems of high data quality requirements, low accuracy of abnormality identification, and inability to identify which specific equipment is abnormal and what type of abnormality it is. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a flow chart of a method for automatically identifying abnormalities in a secondary system of a substation provided by an embodiment of the present invention;

[0025] Figure 2 is a structural diagram of a secondary system abnormality monitoring system involved in an embodiment of the present invention;

[0026] Figure 3 is a secondary system abnormality identification criterion involved in an embodiment of the present invention;

[0027] Figure 4 The present invention is a schematic diagram of the structure of a system for automatically identifying abnormalities in a secondary system of a substation provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0028] Many specific details are set forth in the following description to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways than those described herein, and those skilled in the art can make similar generalizations without violating the connotation of the present invention, so the present invention is not limited to the specific implementation disclosed below.

[0029] The present invention provides a system method for automatically identifying and warning abnormalities of the secondary system (secondary equipment and circuits) of a substation. The technical principle is: using the abnormal mechanism and characteristics of the secondary equipment sampling data to identify the secondary equipment sampling abnormalities, secondary circuit abnormalities, and determine the abnormal types of the secondary equipment and circuits.

[0030] The technical solution adopted is: based on the secondary system abnormality monitoring system, such as Figure 2 As shown, firstly, the voltage and current monitoring data and recording files (voltage and current sampling information of protection, measurement and control devices, etc., device recording or fault recording information) from the secondary equipment are obtained; then the monitoring data and recording files are preliminarily processed to obtain the voltage and current data corresponding to the primary equipment and secondary equipment, and the same source data belonging to the same primary equipment are marked; for each group of voltage and current data, an abnormality discrimination method is applied for discrimination, and an alarm is issued for the secondary equipment or circuit with abnormality according to the discrimination result. More specifically, the present invention provides a method for automatically identifying abnormalities in the secondary system of a substation, such as Figure 1 As shown, the following steps are included:

[0031] Step S101, obtaining voltage and current monitoring data and waveform recording data of secondary equipment.

[0032] Real-time or scheduled acquisition of voltage and current monitoring data of secondary equipment (protection devices, measurement and control devices), device recording files, fault recording files and other types of data containing voltage and current sampling information.

[0033] Step S102, preliminarily processing the voltage and current monitoring data to obtain the voltage and current data corresponding to the primary equipment and the secondary equipment; preliminarily processing the recorded data to extract the primary equipment information and the corresponding voltage and current instantaneous value data.

[0034] Perform preliminary processing on various voltage and current data, including: processing the voltage and current monitoring data of protection devices and measurement and control devices into valid values ​​containing time information, primary equipment name, and secondary equipment name; parsing the recording file and extracting the primary equipment information and the corresponding voltage and current instantaneous value data.

[0035] Step S103, based on the steady-state abnormality identification criterion, steady-state abnormality identification is performed on the voltage and current data, and an abnormality alarm is issued for the equipment that meets the steady-state abnormality identification criterion; based on the transient abnormality identification criterion, transient abnormality identification is performed on the voltage and current instantaneous value data, and an abnormality alarm is issued for the channel that meets the transient abnormality identification criterion.

[0036] The steady-state abnormality identification criterion is as follows: Figure 3 As shown, including: three-phase voltage inconsistency, differential current exceeding the limit, and inconsistency of homologous data.

[0037] The transient abnormality identification criterion is as follows: Figure 3 As shown, including: inconsistency between self-generated and external zero-sequence voltage, zero-sequence voltage exceeding the limit, zero-sequence current exceeding the limit, voltage harmonic exceeding the limit, current harmonic exceeding the limit, and inconsistency of data from the same source.

[0038] Homologous data refers to data that belongs to the same primary device and the same time period.

[0039] Steady-state anomalies are identified based on the voltage and current monitoring data of the protection and measurement and control devices. Transient anomalies are identified based on the transient data of fault recording or device recording. An abnormal alarm is issued for the voltage or current that meets the abnormal identification criteria. More specifically, an abnormal alarm is issued for the device or recording channel identified as abnormal, and the corresponding time, primary equipment name, secondary equipment name, and the reason or criterion for identifying the abnormality are given.

[0040] Based on the same inventive concept, the present invention also provides an automatic identification system 400 for abnormalities in a secondary system of a substation, such as Figure 4 As shown, including:

[0041] The data acquisition module 410 is used to acquire the voltage and current monitoring data and the waveform recording data of the secondary equipment;

[0042] The data preliminary processing module 420 is used to perform preliminary processing on the voltage and current monitoring data to obtain the voltage and current data corresponding to the primary equipment and the secondary equipment; perform preliminary processing on the recorded wave data to extract the primary equipment information and the corresponding voltage and current instantaneous value data;

[0043] The abnormality identification module 430 is used to identify steady-state abnormalities of the voltage and current data based on steady-state abnormality identification criteria, and issue abnormality alarms for devices that meet the steady-state abnormality identification criteria; based on transient abnormality identification criteria, it identifies transient abnormalities of the voltage and current instantaneous value data, and issues abnormality alarms for channels that meet the transient abnormality identification criteria.

[0044] Furthermore, the steady-state abnormality identification criteria include: three-phase voltage inconsistency, differential current exceeding the limit, and inconsistency of homologous data.

[0045] Furthermore, the transient abnormality identification criteria include: inconsistency between self-generated and external zero-sequence voltages, zero-sequence voltage exceeding a limit, zero-sequence current exceeding a limit, voltage harmonic exceeding a limit, current harmonic exceeding a limit, and inconsistency between homologous data.

[0046] Furthermore, homologous data refers to data belonging to the same primary device and the same time period.

[0047] Furthermore, it also includes:

[0048] The abnormal alarm module is used to issue abnormal alarm information, give the corresponding occurrence time, primary device name, secondary device name, and the cause or criterion for identifying the abnormality.

[0049] Compared with the prior art, the technical measures and improvements of the present invention include the following points:

[0050] (1) Secondary system anomaly identification method using normal operation monitoring data and disturbance recording transient data

[0051] The existing secondary system anomaly identification method based on fault recorder only analyzes transient conditions with electrical quantity disturbances, while automatic anomaly analysis is not implemented for normal operating conditions.

[0052] The present invention uses both normal operation monitoring data and disturbance recording transient data to identify secondary system anomalies, which can cover all operating conditions of secondary equipment. The normal operation monitoring data includes: voltage and current sampling (online monitoring) data of protection devices and measurement and control devices, and the recording data includes all voltage and current data before and after the recording is started in the protection device recording file and the fault recorder file.

[0053] (2) Abnormal steady-state identification method of secondary system based on normal operation monitoring data

[0054] Steady-state anomaly identification is performed for each set of voltage and current monitoring data of the protection device and the measurement and control device. The steady-state anomaly identification methods include three-phase voltage inconsistency, differential current exceeding the limit, and inconsistency of the same-source data.

[0055] Among them, the three-phase voltage inconsistency is for the monitored three-phase voltage, judging whether the three-phase voltage amplitudes are consistent and whether they are all rated voltages. If they are inconsistent and deviate from the rated voltage by more than the limit, it may be caused by abnormal protection voltage circuit or sampling, and an alarm needs to be issued.

[0056] The differential current over-limit function determines whether the monitored differential current exceeds the limit. If the limit is exceeded, it may be caused by abnormal protection of the current circuit or sampling, and an alarm needs to be issued.

[0057] Inconsistency of the same source data. Multiple sets of voltage (or current) monitoring data corresponding to the same primary device are compared for consistency, that is, multiple sets of voltages are compared with each other, and multiple sets of currents are compared with each other. If there is inconsistency, it may be caused by abnormal voltage (or current) circuit or sampling of the device, and an alarm needs to be issued.

[0058] (3) Secondary system anomaly identification method based on recorded data

[0059] For each set of voltage (or current) data extracted from the fault recording file or the device recording file, transient anomaly identification is performed. The transient anomaly identification methods include inconsistency between self-generated and external zero-sequence voltage, zero-sequence voltage exceeding the limit, zero-sequence current exceeding the limit, voltage harmonic exceeding the limit, current harmonic exceeding the limit, and inconsistency of homologous data.

[0060] Among them, the inconsistency between the self-generated and external zero-sequence voltages is compared for consistency with the three-phase voltage and zero-sequence voltage amplitudes of the fault recording. If there is inconsistency, it may be caused by abnormalities in the three-phase voltage or zero-sequence voltage circuit or sampling of the fault recording, and an alarm needs to be issued.

[0061] The zero-sequence voltage or zero-sequence current exceeds the limit. The zero-sequence voltage or zero-sequence current calculated from the three-phase voltage or three-phase current of the fault recording or the device recording for several cycles before the start of the recording is judged as exceeding the limit. If the zero-sequence voltage or zero-sequence current exceeds the limit, it may be due to the three-phase voltage or three-phase current circuit or sampling abnormality, and an alarm needs to be issued.

[0062] Voltage harmonic over-limit judgment is made on the harmonics of the three-phase voltage recorded by the fault recording or the device recording. If the voltage harmonic exceeds the limit (different limit values ​​are set before and after the recording is started), it may be an abnormality caused by false connection of the voltage circuit, multiple grounding points, etc., and an alarm needs to be issued.

[0063] The current harmonic over-limit judgment is made on the harmonics of the three-phase current for several cycles before the fault recording or device recording is started. If the current harmonic exceeds the limit, it may be caused by virtual connection of the current circuit, multiple grounding, etc., and an alarm needs to be issued; the three-phase current harmonic over-limit judgment is made after the fault recording or device recording is started. If the current harmonic exceeds the limit, it may be caused by current transformer saturation, etc., and an alarm needs to be issued.

[0064] Inconsistency of the same source data is compared for consistency of multiple sets of voltage (or current) data corresponding to the same primary device, that is, multiple sets of voltages are compared with each other, and multiple sets of currents are compared with each other. If there is inconsistency, it may be caused by abnormal voltage (or current) circuit or sampling of the device, and an alarm needs to be issued.

[0065] The present invention provides a method and system for automatically identifying abnormalities in a secondary system of a substation, and the effects of the invention include the following aspects:

[0066] (1) Comprehensively utilize normal operation monitoring data and recording data to identify secondary system anomalies, and realize abnormal monitoring of secondary equipment under all operating conditions

[0067] The existing secondary system anomaly identification method based on fault recorder only analyzes transient conditions with electrical quantity disturbances, while normal operating conditions do not achieve abnormal monitoring and automatic abnormality analysis.

[0068] The present invention utilizes both normal operation monitoring data and recorded wave data to identify secondary system anomalies, which can cover all operating conditions of secondary equipment and realize secondary system anomaly monitoring and identification analysis under all operating conditions.

[0069] The normal operation monitoring data include: voltage and current sampling online monitoring data of protection devices and measurement and control devices; the recording data include all voltage and current data before and after the recording is started in the protection device recording files and fault recorder files.

[0070] (2) Propose a variety of secondary system anomaly identification methods based on normal operation monitoring data

[0071] The present invention proposes an abnormal identification method for three-phase voltage inconsistency, differential current over-limit, and same-source data inconsistency based on voltage and current sampling monitoring data of normal operation of a protection device and a measurement and control device.

[0072] Among them, the three-phase voltage inconsistency judgment method can identify the protection voltage circuit or sampling abnormality by judging whether the three-phase voltage amplitudes are consistent and whether they deviate from the rated voltage.

[0073] The differential current over-limit judgment method can identify the protection current loop or sampling abnormality by judging whether the differential current exceeds the limit.

[0074] The method for distinguishing inconsistency of data from the same source can identify voltage (or current) circuit or sampling anomalies of the device by performing consistency comparison on multiple sets of voltage (or current) data corresponding to the same primary device.

[0075] (3) Propose a variety of secondary system anomaly identification methods based on recorded data

[0076] The present invention proposes a variety of secondary system abnormality identification methods based on recorded data, including inconsistency between self-generated and external zero-sequence voltage, zero-sequence voltage exceeding the limit, zero-sequence current exceeding the limit, voltage harmonic exceeding the limit, current harmonic exceeding the limit, and inconsistency of homologous data.

[0077] Among them, the method for distinguishing the inconsistency between self-produced and external zero-sequence voltages compares the consistency of the three-phase voltage and zero-sequence voltage amplitudes of the fault recording to identify the fault recording three-phase voltage or zero-sequence voltage circuit or sampling abnormalities.

[0078] The method for judging whether the zero-sequence voltage exceeds the limit or the zero-sequence current exceeds the limit is to judge whether the zero-sequence voltage or the zero-sequence current exceeds the limit for several cycles before the fault recording or the device recording is started, so as to identify the abnormality of the three-phase voltage or three-phase current circuit or sampling.

[0079] The voltage harmonic over-limit judgment method is to judge the over-limit of the harmonics of the three-phase voltage recorded by the fault recording or the device recording, and identify the abnormalities caused by the virtual connection of the voltage circuit, multiple grounding points, etc.

[0080] The current harmonic over-limit judgment method is to judge the over-limit of the harmonics of the three-phase current for several cycles before the fault recording or the device recording is started, and identify the abnormalities caused by the virtual connection of the current circuit, multiple grounding and other reasons; by judging the over-limit of the three-phase current harmonics after the fault recording or the device recording is started, the abnormalities caused by the saturation of the current transformer and other reasons are identified.

[0081] The method for distinguishing inconsistency of homologous data is to identify voltage (or current) circuit or sampling anomalies of the device by performing consistency comparison on multiple sets of voltage (or current) data of the same primary device.

[0082] Those skilled in the art will appreciate that embodiments of the present invention may be provided as methods, systems, or computer program products. Therefore, the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present invention may take the form of a computer program product implemented 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.

[0083] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0084] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0085] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0086] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the relevant field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents, and any modifications or equivalents that do not depart from the spirit and scope of the present invention should be included in the scope of the claims of the present invention.

Claims

1. A method for automatically identifying abnormalities in a secondary system of a substation, characterized in that: include: Obtain voltage and current monitoring data and waveform data of secondary equipment; Perform preliminary processing on the voltage and current monitoring data to obtain the voltage and current data corresponding to the primary equipment and the secondary equipment; perform preliminary processing on the recorded wave data to extract the primary equipment information and the corresponding voltage and current instantaneous value data; Based on the steady-state abnormality identification criterion, the voltage and current data are subjected to steady-state abnormality identification, and an abnormality alarm is issued for the equipment that meets the steady-state abnormality identification criterion; Based on the transient abnormality identification criterion, transient abnormality identification is performed on the voltage and current instantaneous value data, and an abnormality alarm is issued for the channel that meets the transient abnormality identification criterion.

2. The method according to claim 1, characterized in that The steady-state abnormality identification criteria include: three-phase voltage inconsistency, differential current exceeding the limit, and same-source data inconsistency.

3. The method according to claim 1, characterized in that The transient abnormality identification criteria include: inconsistency between self-generated and external zero-sequence voltages, zero-sequence voltage exceeding a limit, zero-sequence current exceeding a limit, voltage harmonic exceeding a limit, current harmonic exceeding a limit, and inconsistency of homologous data.

4. The method according to claim 2 or 3, characterized in that: Homologous data refers to data that belongs to the same primary device and the same time period.

5. The method according to claim 1, characterized in that Also includes: After the abnormal alarm information is issued, the corresponding occurrence time, primary device name, secondary device name, and the reason or criterion for identifying the abnormality are given.

6. An automatic identification system for abnormalities in the secondary system of a substation, characterized in that: include: Data acquisition module, used to obtain voltage and current monitoring data and waveform data of secondary equipment; The data preliminary processing module is used to perform preliminary processing on the voltage and current monitoring data to obtain the voltage and current data corresponding to the primary equipment and the secondary equipment; perform preliminary processing on the recorded wave data to extract the primary equipment information and the corresponding voltage and current instantaneous value data; An abnormality identification module, used to identify the steady-state abnormality of the voltage and current data based on the steady-state abnormality identification criterion, and issue an abnormality alarm for the equipment that meets the steady-state abnormality identification criterion; Based on the transient abnormality identification criterion, transient abnormality identification is performed on the voltage and current instantaneous value data, and an abnormality alarm is issued for the channel that meets the transient abnormality identification criterion.

7. The system according to claim 6, characterized in that The steady-state abnormality identification criteria include: three-phase voltage inconsistency, differential current exceeding the limit, and same-source data inconsistency.

8. The system according to claim 6, characterized in that The transient abnormality identification criteria include: inconsistency between self-generated and external zero-sequence voltages, zero-sequence voltage exceeding a limit, zero-sequence current exceeding a limit, voltage harmonic exceeding a limit, current harmonic exceeding a limit, and inconsistency of homologous data.

9. The method according to claim 7 or 8, characterized in that: Homologous data refers to data that belongs to the same primary device and the same time period.

10. The method according to claim 1, characterized in that Also includes: The abnormal alarm module is used to issue abnormal alarm information, give the corresponding occurrence time, primary device name, secondary device name, and the cause or criterion for identifying the abnormality.

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