A method and device for monitoring reactor circuit defects based on busbar mutual inductor

Abstract

The present invention discloses a method and device for monitoring defects in a reactor circuit based on a busbar transformer, the method comprising: obtaining a secondary side electrical signal of a busbar transformer; saving the waveform corresponding to the mutation signal in the secondary side electrical signal, the waveform corresponding to the preset amplitude-frequency signal, and the waveform corresponding to the opening and closing signal of each reactor as a transient waveform; dividing the transient waveform into multiple groups of switching transient waveforms according to the time when each reactor on the same bus is switched on, each group of switching transient waveforms corresponds to a reactor circuit; extracting features of the waveforms in the time period containing the target frequency in each group of switching transient waveforms; if the deviation value between the extracted feature quantity and the historical feature quantity recorded in the historical data is greater than a preset threshold value, the reactor circuit corresponding to the group of switching transient waveforms has defects. By adopting the present invention, by installing a detection device on the secondary side of the busbar transformer, the working conditions of each reactive circuit on the same busbar can be detected for a long time and defects can be found in time.

Description

Technical Field

[0001] The present invention relates to the technical field of power grid operation and maintenance, and in particular to a method and device for monitoring reactor circuit defects based on a busbar mutual inductor. Background Art

[0002] Frequent fires and combustion of reactors are an important issue affecting the safe and stable operation of the power grid. Vacuum circuit breakers switching reactive equipment may generate restrike overvoltage and pre-strike through voltage, causing insulation damage or even tripping of the equipment, endangering the safe and stable operation of the power grid. At present, there is no online monitoring device for reactive switching of the power grid, and it is impossible to carry out online monitoring of reactive equipment. Instead, there are only offline testing devices. The offline method uses a voltage divider to perform a power outage test to obtain transient overvoltage. This method requires powering off the equipment and installing contact monitoring equipment before switching operations. The workload is large, and there are potential safety issues in on-site testing. Since data can only be obtained during the test, the sample is limited, and it is impossible to timely reflect whether the operating status of the actual equipment after the characteristics change during operation meets the requirements. It is difficult to monitor the operation of the equipment for a long time, so its application is limited. Regarding the defect development process of the transient device itself during repeated switching, the power grid currently does not have an online monitoring device or method for full life cycle observation of reactive equipment, and it is impossible to achieve early warning of defects.

[0003] Traditionally, it is believed that the transient process generated during the switching process must be tested by the voltage test of the switched part. Therefore, the existing technology and test device adopt the method of installing a voltage divider at the head and end of the reactive equipment to be tested. It is necessary to shut down the power and change the wiring once. Short circuit must be strictly avoided during the installation process. After installation, the equipment is manually switched multiple times, and the overvoltage and whether it reignites during the switching process are tested. During the test process, the personnel need to operate the instrument on site. Once the transient voltage is too high and a short circuit occurs, it may also pose a threat to personal safety. In addition, only the current state of the equipment can be monitored to a limited extent, and the long-term operation state of the equipment cannot be reflected. Once the equipment has defects and the circuit changes, it will cause equipment failure. At present, a large number of operating equipment in the power grid are in a state of no monitoring, resulting in frequent failures or defects. Summary of the invention

[0004] The embodiment of the present invention provides a method and device for monitoring reactor circuit defects based on a bus transformer. By installing a detection device on the secondary side of the bus transformer, the working conditions of each reactive circuit of the same bus can be detected for a long time and defects can be discovered in time.

[0005] To achieve the above-mentioned object, a first aspect of an embodiment of the present application provides a method for monitoring a reactor circuit defect based on a busbar transformer, comprising:

[0006] Obtaining the secondary side electrical signal of the busbar transformer;

[0007] The waveform corresponding to the sudden change signal in the secondary side electrical signal, the waveform corresponding to the preset amplitude-frequency signal, and the waveform corresponding to the opening and closing signal of each reactor are saved as transient waveforms; the preset amplitude-frequency signal refers to an electrical signal whose frequency and amplitude simultaneously exceed a preset threshold value;

[0008] According to the time when each reactor on the same bus is switched on, the transient waveform is divided into multiple groups of switching transient waveforms, each group of switching transient waveforms corresponds to a reactor circuit; when each reactor is switched on, the secondary side electrical signal will generate an oscillation of a certain frequency;

[0009] Extract features of the waveforms in the time period containing the target frequency in each group of switching transient waveforms;

[0010] If the deviation between the extracted characteristic quantity and the historical characteristic quantity recorded in the historical data is greater than a preset threshold, the reactor circuit corresponding to the switching transient waveform of this group is defective.

[0011] In a possible implementation manner of the first aspect, extracting features of waveforms in a time period containing a target frequency in each group of switching transient waveforms specifically includes:

[0012] If the waveform frequency of the group of gate transient waveforms in a time period is equal to the target frequency, feature extraction is performed on the waveform in this time period, and the extracted feature quantities include oscillation amplitude, oscillation frequency, attenuation time constant and whether there is an amplitude mutation point.

[0013] In a possible implementation manner of the first aspect, the deviation value between the extracted feature quantity and the historical feature quantity recorded in the historical data is greater than a preset threshold, specifically including:

[0014] The deviation value of the dispersion of the oscillation amplitude exceeds the preset threshold, or,

[0015] The deviation of the oscillation frequency exceeds the preset threshold, or,

[0016] The deviation of the decay time constant exceeds the preset threshold, or,

[0017] The deviation value of the oscillation voltage waveform exceeds a preset threshold.

[0018] In a possible implementation of the first aspect, if the deviation value between the extracted characteristic quantity and the historical characteristic quantity recorded in the historical data is greater than a preset threshold, the reactor circuit corresponding to the group of switching transient waveforms has defects, specifically including:

[0019] The deviation value of the decay time constant is greater than the preset threshold value, and the device parameters of the reactor circuit undergo an adverse change.

[0020] In a possible implementation of the first aspect, if the deviation value between the extracted characteristic quantity and the historical characteristic quantity recorded in the historical data is greater than a preset threshold, the reactor circuit corresponding to the group of switching transient waveforms has defects, specifically including:

[0021] The deviation value of the oscillating voltage waveform is greater than a preset threshold value, and the reactor circuit has an insulation breakdown defect.

[0022] A second aspect of an embodiment of the present application provides a busbar transformer-based reactor circuit defect monitoring device, which is applied to the secondary side of the busbar transformer, including:

[0023] A signal acquisition module, used to acquire the secondary side electrical signal of the busbar transformer;

[0024] A waveform storage module is used to store the waveform corresponding to the sudden change signal in the secondary side electrical signal, the waveform corresponding to the preset amplitude-frequency signal, and the waveform corresponding to the opening and closing signal of each reactor as a transient waveform; the preset amplitude-frequency signal refers to an electrical signal whose frequency and amplitude simultaneously exceed a preset threshold value;

[0025] A division module, for dividing the transient waveform into multiple groups of switching transient waveforms according to the switching moments of various reactors on the same bus, each group of switching transient waveforms corresponding to one reactor circuit;

[0026] A feature extraction module is used to extract features from the waveforms in the time period containing the target frequency in each group of switching transient waveforms;

[0027] The defect analysis module is used to determine that there is a defect in the reactor circuit corresponding to the switching transient waveform of the group if the deviation value between the extracted characteristic quantity and the historical characteristic quantity recorded in the historical data is greater than a preset threshold.

[0028] In a possible implementation of the second aspect, if the waveform frequency of the group of gate transient waveforms within a time period is equal to the target frequency, feature extraction is performed on the waveform within this time period, and the extracted feature quantities include oscillation amplitude, oscillation frequency, attenuation time constant and whether there is an amplitude mutation point.

[0029] In a possible implementation manner of the second aspect, the feature extraction module is specifically used to:

[0030] If the waveform frequency of the group of gate transient waveforms in a time period is equal to the target frequency, feature extraction is performed on the waveform in this time period, and the extracted feature quantities include oscillation amplitude, oscillation frequency, attenuation time constant and whether there is an amplitude mutation point.

[0031] In a possible implementation manner of the second aspect, the deviation value between the extracted feature quantity and the historical feature quantity recorded in the historical data is greater than a preset threshold, specifically including:

[0032] The deviation value of the dispersion of the oscillation amplitude exceeds the preset threshold, or,

[0033] The deviation of the oscillation frequency exceeds the preset threshold, or,

[0034] The deviation of the decay time constant exceeds the preset threshold, or,

[0035] The deviation value of the oscillation voltage waveform exceeds a preset threshold.

[0036] In a possible implementation manner of the second aspect, the defect analysis module is specifically configured to:

[0037] If the deviation value of the decay time constant is greater than a preset threshold value, the device parameters of the reactor circuit undergo an adverse change.

[0038] In a possible implementation manner of the second aspect, the defect analysis module is specifically configured to:

[0039] If the deviation value of the oscillating voltage waveform is greater than a preset threshold value, the reactor circuit has an insulation breakdown defect.

[0040] Compared with the prior art, the embodiment of the present invention provides a method and device for monitoring defects in a reactor circuit based on a bus transformer. It is not necessary to install a voltage divider to change the primary wiring of the system. It is only necessary to install a voltage signal acquisition device on the secondary side of the bus transformer. By observing the high-frequency components of the reactive circuit on the secondary side voltage signal, a real-time monitoring method of an electrical signal is used instead of an offline reconnection test. Since there is no need to change the bus wiring, add external equipment such as a voltage divider, or perform additional power outage maintenance on external equipment, it is safer.

[0041] In addition, there are often 4 or more reactive compensation outgoing lines connected to the busbar. Observation from the secondary side of the busbar voltage can reflect the switching process of all reactive devices at one time, which is extremely economical. Finally, online monitoring can obtain transient data for a longer period of time. By extracting the voltage characteristic quantity, the early defect identification criteria of the reactor are obtained, which can realize effective control of the reactor fault. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 It is a flow chart of a method for monitoring reactor circuit defects based on a busbar transformer provided by an embodiment of the present invention;

[0043] Figure 2 It is a schematic diagram of switching oscillation of a secondary side electrical signal in one embodiment of the present invention;

[0044] Figure 3 It is a schematic diagram of the access of a reactor circuit defect monitoring device based on a busbar transformer provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0045] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0046] See also Figure 1 An embodiment of the present invention provides a method for monitoring a reactor circuit defect based on a busbar transformer, comprising:

[0047] S10. Obtain the secondary side electrical signal of the busbar transformer.

[0048] S11. Save the waveform corresponding to the sudden change signal in the secondary side electrical signal, the waveform corresponding to the preset amplitude-frequency signal, and the waveform corresponding to the opening and closing signal of each reactor as transient waveforms; the preset amplitude-frequency signal refers to an electrical signal whose frequency and amplitude simultaneously exceed a preset threshold.

[0049] S12. According to the moment when each reactor on the same bus is switched on, the transient waveform is divided into multiple groups of switching transient waveforms, each group of switching transient waveforms corresponds to a reactor circuit; when each reactor is switched on, the secondary side electrical signal will generate oscillations of a certain frequency.

[0050] S13, extracting features of the waveforms in the time period containing the target frequency in each group of switching transient waveforms.

[0051] S14. If the deviation between the extracted characteristic quantity and the historical characteristic quantity recorded in the historical data is greater than a preset threshold, the reactor circuit corresponding to the switching transient waveform of the group is defective.

[0052] In S11, the waveform corresponding to the sudden change signal in the secondary side electrical signal, the waveform corresponding to the preset amplitude-frequency signal, and the waveform corresponding to the opening and closing signal of each reactor are saved as transient waveforms. This is to make the saved transient waveform cover as wide a range as possible and avoid ignoring the switching process of individual reactors.

[0053] See also Figure 2 Since the bus voltage oscillates during the reactor opening process, the embodiment of the present invention uses this transient process to judge the switching process. In the past, it was believed that the high-frequency voltage of the reactive circuit must be observed for reignition. Through actual measurement, it was found that the bus voltage can also reflect the high-frequency component, and since the high-frequency transfer characteristics of the PT (bus transformer) meet the recognition requirements of the reignition waveform, the reignition can be observed at the PT secondary.

[0054] It should be noted that the degree of oscillation during the opening process of different reactors is different, and experiments and statistical analysis need to be carried out in advance.

[0055] The embodiment of the present invention intends to achieve long-term monitoring of the switching of reactive equipment in the entire station through the secondary voltage monitoring of the bus voltage transformer. On the one hand, there is no need to install a voltage divider to change the primary wiring of the system, which ensures the safety of equipment and personnel. On the other hand, since it can be installed for a long time, the operating conditions of the equipment in different periods can be observed for comprehensive comparison, and the measured results are more feasible. On the other hand, since no primary equipment is involved, the cost is extremely low and it is easy to promote. Since the online monitoring method replaces the traditional offline manual switching test, it has the advantages of high safety, large amount of data acquisition, low testing difficulty and extremely high economy. Finally, in addition to its own low cost, the voltage observation by the bus PT can simultaneously obtain the action status of each reactive line of the same bus, and the application range is wider.

[0056] Exemplarily, the feature extraction of the waveform in the time period containing the target frequency in each group of switching transient waveforms specifically includes:

[0057] If the waveform frequency of the group of gate transient waveforms in a time period is equal to the target frequency, feature extraction is performed on the waveform in this time period, and the extracted feature quantities include oscillation amplitude, oscillation frequency, attenuation time constant and whether there is an amplitude mutation point.

[0058] Exemplarily, the deviation value between the extracted feature quantity and the historical feature quantity recorded in the historical data is greater than a preset threshold, specifically including:

[0059] The deviation value of the dispersion of the oscillation amplitude exceeds the preset threshold, or,

[0060] The deviation of the oscillation frequency exceeds the preset threshold, or,

[0061] The deviation of the decay time constant exceeds the preset threshold, or,

[0062] The deviation value of the oscillation voltage waveform exceeds a preset threshold.

[0063] Exemplarily, if the deviation value between the extracted characteristic quantity and the historical characteristic quantity recorded in the historical data is greater than a preset threshold, the reactor circuit corresponding to the switching transient waveform of the group is defective, specifically including:

[0064] The deviation value of the decay time constant is greater than the preset threshold value, and the device parameters of the reactor circuit undergo an adverse change.

[0065] Exemplarily, if the deviation value between the extracted characteristic quantity and the historical characteristic quantity recorded in the historical data is greater than a preset threshold, the reactor circuit corresponding to the switching transient waveform of the group is defective, specifically including:

[0066] The deviation value of the oscillating voltage waveform is greater than the preset threshold value, and the reactor circuit has an insulation breakdown defect. The extracted feature quantity is compared with the previous data. When the dispersion of the amplitude exceeds a certain value compared with the previous data, the frequency exceeds a certain value compared with the past, the decay time constant exceeds a certain value compared with the past, and there is a sudden change in the voltage waveform during the oscillation process (that is, there is a sudden change in the amplitude and derivative), if one or more of the above conditions are met, it is considered that the reactor circuit has a defect. For example, when the decay time constant changes, it indicates that the circuit inductance, capacitance and resistance values ​​have changed, which must indicate that the parameters of the reactor, capacitor and other equipment have changed. When the oscillating voltage waveform suddenly changes, it indicates that insulation breakdown may have occurred. When it is necessary to avoid re-investment, relevant tests should be carried out.

[0067] Compared with the prior art, the embodiment of the present invention provides a method for monitoring defects in a reactor circuit based on a bus transformer. This method does not require the installation of a voltage divider to change the primary wiring of the system. It only requires the installation of a voltage signal acquisition device on the secondary side of the bus transformer. By observing the high-frequency components of the reactive circuit on the secondary side voltage signal, a real-time monitoring method of an electrical signal is used instead of an offline reconnection test. Since there is no need to change the bus wiring, add external equipment such as a voltage divider, or perform additional power outage maintenance on external equipment, this method is safer.

[0068] In addition, there are often 4 or more reactive compensation outgoing lines connected to the busbar. Observation from the secondary side of the busbar voltage can reflect the switching process of all reactive devices at one time, which is extremely economical. Finally, online monitoring can obtain transient data for a longer period of time. By extracting the voltage characteristic quantity, the early defect identification criteria of the reactor are obtained, which can realize effective control of the reactor fault.

[0069] A second aspect of an embodiment of the present application provides a busbar transformer-based reactor circuit defect monitoring device, which is applied to the secondary side of the busbar transformer and includes a signal acquisition module, a waveform storage module, a division module, a feature extraction module and a defect analysis module.

[0070] A signal acquisition module, used to acquire the secondary side electrical signal of the busbar transformer;

[0071] A waveform storage module is used to store the waveform corresponding to the sudden change signal in the secondary side electrical signal, the waveform corresponding to the preset amplitude-frequency signal, and the waveform corresponding to the opening and closing signal of each reactor as a transient waveform; the preset amplitude-frequency signal refers to an electrical signal whose frequency and amplitude simultaneously exceed a preset threshold value;

[0072] A division module, for dividing the transient waveform into multiple groups of switching transient waveforms according to the switching moments of various reactors on the same bus, each group of switching transient waveforms corresponding to one reactor circuit;

[0073] A feature extraction module is used to extract features from the waveforms in the time period containing the target frequency in each group of switching transient waveforms;

[0074] The defect analysis module is used to determine that there is a defect in the reactor circuit corresponding to the switching transient waveform of the group if the deviation value between the extracted characteristic quantity and the historical characteristic quantity recorded in the historical data is greater than a preset threshold.

[0075] See also Figure 3 Generally, the device of the present invention is directly connected to the "PT secondary voltage" shown in the figure. The voltage measurement points 2, 3, and 5 in the figure all need to install additional voltage dividers, while the embodiment of the present invention only needs to install a voltage signal acquisition device on the secondary side of the bus PT, without actually changing the primary wiring, so it can be installed for a long time.

[0076] Exemplarily, if the waveform frequency of the group of gate transient waveforms in a time period is equal to the target frequency, feature extraction is performed on the waveform in this time period, and the extracted feature quantities include oscillation amplitude, oscillation frequency, attenuation time constant and whether there is an amplitude mutation point.

[0077] Exemplarily, the feature extraction module is specifically used for:

[0078] If the waveform frequency of the group of gate transient waveforms in a time period is equal to the target frequency, feature extraction is performed on the waveform in this time period, and the extracted feature quantities include oscillation amplitude, oscillation frequency, attenuation time constant and whether there is an amplitude mutation point.

[0079] Exemplarily, the deviation value between the extracted feature quantity and the historical feature quantity recorded in the historical data is greater than a preset threshold, specifically including:

[0080] The deviation value of the dispersion of the oscillation amplitude exceeds the preset threshold, or,

[0081] The deviation of the oscillation frequency exceeds the preset threshold, or,

[0082] The deviation of the decay time constant exceeds the preset threshold, or,

[0083] The deviation value of the oscillation voltage waveform exceeds a preset threshold.

[0084] Exemplarily, the defect analysis module is specifically used for:

[0085] If the deviation value of the decay time constant is greater than a preset threshold value, the device parameters of the reactor circuit undergo an adverse change.

[0086] Exemplarily, the defect analysis module is specifically used for:

[0087] If the deviation value of the oscillating voltage waveform is greater than a preset threshold value, the reactor circuit has an insulation breakdown defect.

[0088] Compared with the prior art, the embodiment of the present invention provides a reactor circuit defect monitoring device based on a bus transformer. It does not need to install a voltage divider to change the primary side wiring of the system. It only needs to install a voltage signal acquisition device on the secondary side of the bus transformer. By observing the high-frequency component of the reactive circuit on the secondary side voltage signal, a real-time monitoring method of an electrical signal is used instead of an offline reconnection test. Since there is no need to change the bus wiring, no external voltage divider and other equipment, and no additional power outage maintenance on external equipment, it is safer.

[0089] In addition, there are often 4 or more reactive compensation outgoing lines connected to the busbar. Observation from the secondary side of the busbar voltage can reflect the switching process of all reactive devices at one time, which is extremely economical. Finally, online monitoring can obtain transient data for a longer period of time. By extracting the voltage characteristic quantity, the early defect identification criteria of the reactor are obtained, which can realize effective control of the reactor fault.

[0090] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working process of the device described above can refer to the corresponding process in the aforementioned method embodiment, and will not be described again here.

[0091] The above is a preferred embodiment of the present invention. It should be pointed out that a person skilled in the art can make several improvements and modifications without departing from the principle of the present invention. These improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. A method for monitoring reactor circuit defects based on busbar mutual inductor, characterized in that: include: Obtaining the secondary side electrical signal of the busbar transformer; The waveform corresponding to the sudden change signal in the secondary side electrical signal, the waveform corresponding to the preset amplitude-frequency signal, and the waveform corresponding to the opening and closing signal of each reactor are saved as transient waveforms; the preset amplitude-frequency signal refers to an electrical signal whose frequency and amplitude simultaneously exceed a preset threshold value; According to the time when each reactor on the same bus is switched on, the transient waveform is divided into multiple groups of switching transient waveforms, each group of switching transient waveforms corresponds to a reactor circuit; when each reactor is switched on, the secondary side electrical signal will generate an oscillation of a certain frequency; Extract features of the waveforms in the time period containing the target frequency in each group of switching transient waveforms; If the deviation between the extracted characteristic quantity and the historical characteristic quantity recorded in the historical data is greater than a preset threshold, the reactor circuit corresponding to the switching transient waveform of this group is defective.

2. The method for monitoring reactor circuit defects based on busbar mutual inductor according to claim 1, characterized in that: The feature extraction of the waveform in the time period containing the target frequency in each group of switching transient waveforms specifically includes: If the waveform frequency of the group of gate transient waveforms in a time period is equal to the target frequency, feature extraction is performed on the waveform in this time period, and the extracted feature quantities include oscillation amplitude, oscillation frequency, attenuation time constant and whether there is an amplitude mutation point.

3. The method for monitoring reactor circuit defects based on busbar mutual inductor according to claim 1, characterized in that: The deviation between the extracted feature quantity and the historical feature quantity recorded in the historical data is greater than a preset threshold, specifically including: The deviation value of the dispersion of the oscillation amplitude exceeds the preset threshold, or, The deviation of the oscillation frequency exceeds the preset threshold, or, The deviation of the decay time constant exceeds the preset threshold, or, The deviation value of the oscillation voltage waveform exceeds a preset threshold.

4. The method for monitoring reactor circuit defects based on busbar mutual inductor according to claim 1, characterized in that: If the deviation between the extracted characteristic quantity and the historical characteristic quantity recorded in the historical data is greater than a preset threshold, the reactor circuit corresponding to the switching transient waveform of the group has defects, specifically including: The deviation value of the decay time constant is greater than the preset threshold value, and the device parameters of the reactor circuit undergo an adverse change.

5. The method for monitoring reactor circuit defects based on busbar mutual inductor according to claim 1, characterized in that: If the deviation between the extracted characteristic quantity and the historical characteristic quantity recorded in the historical data is greater than a preset threshold, the reactor circuit corresponding to the switching transient waveform of the group has defects, specifically including: The deviation value of the oscillating voltage waveform is greater than a preset threshold value, and the reactor circuit has an insulation breakdown defect.

6. A reactor circuit defect monitoring device based on busbar mutual inductor, characterized in that: Applied to the secondary side of busbar transformers, including: A signal acquisition module, used to acquire the secondary side electrical signal of the busbar transformer; A waveform storage module is used to store the waveform corresponding to the sudden change signal in the secondary side electrical signal, the waveform corresponding to the preset amplitude-frequency signal, and the waveform corresponding to the opening and closing signal of each reactor as a transient waveform; the preset amplitude-frequency signal refers to an electrical signal whose frequency and amplitude simultaneously exceed a preset threshold value; A division module is used to divide the transient waveform into multiple groups of switching transient waveforms according to the time when each reactor on the same bus is switched, and each group of switching transient waveforms corresponds to a reactor circuit; when each reactor is switched, the secondary side electrical signal will generate an oscillation of a certain frequency; A feature extraction module is used to extract features from the waveforms in the time period containing the target frequency in each group of switching transient waveforms; The defect analysis module is used to determine that there is a defect in the reactor circuit corresponding to the switching transient waveform of the group if the deviation value between the extracted characteristic quantity and the historical characteristic quantity recorded in the historical data is greater than a preset threshold.

7. The reactor circuit defect monitoring device based on busbar mutual inductor according to claim 6, characterized in that: The feature extraction module is specifically used for: If the waveform frequency of the group of gate transient waveforms in a time period is equal to the target frequency, feature extraction is performed on the waveform in this time period, and the extracted feature quantities include oscillation amplitude, oscillation frequency, attenuation time constant and whether there is an amplitude mutation point.

8. The reactor circuit defect monitoring device based on busbar mutual inductor according to claim 6, characterized in that: The deviation between the extracted feature quantity and the historical feature quantity recorded in the historical data is greater than a preset threshold, specifically including: The deviation value of the dispersion of the oscillation amplitude exceeds the preset threshold, or, The deviation of the oscillation frequency exceeds the preset threshold, or, The deviation of the decay time constant exceeds the preset threshold, or, The deviation value of the oscillation voltage waveform exceeds a preset threshold.

9. The reactor circuit defect monitoring device based on busbar mutual inductor according to claim 6, characterized in that: The defect analysis module is specifically used for: If the deviation value of the decay time constant is greater than a preset threshold value, the device parameters of the reactor circuit undergo an adverse change.

10. The reactor circuit defect monitoring device based on busbar mutual inductor according to claim 6, characterized in that: The defect analysis module is specifically used for: If the deviation value of the oscillating voltage waveform is greater than a preset threshold value, the reactor circuit has an insulation breakdown defect.

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