A high-voltage switch PT cabinet operation monitoring device and its application method

Abstract

The present invention discloses a high-voltage switch PT cabinet operation monitoring device and an application method thereof. The high-voltage switch PT cabinet operation monitoring device of the present invention comprises a PT neutral point current detection unit, an overvoltage monitoring unit, an ultrasonic partial discharge monitoring unit and a control unit. The output ends of the PT neutral point current detection unit, the overvoltage monitoring unit and the ultrasonic partial discharge monitoring unit are respectively connected to the control unit; the application method of the present invention comprises PT neutral point current detection, overvoltage monitoring and ultrasonic partial discharge monitoring. The present invention can solve the problems of frequent overvoltage faults, difficult detuning and difficult internal fault monitoring of high-voltage PT cabinets, can monitor the operation status of PT cabinets efficiently, accurately and comprehensively, and can be used to realize intelligent fault elimination of specific operation defects.

Description

Technical Field

[0001] The present invention relates to the field of intelligent operation and inspection of power systems, and specifically to a high-voltage switch PT cabinet operation monitoring device and an application method thereof, which can be used to automatically monitor, eliminate and warn of operation risks such as operation overvoltage and partial discharge defects of a high-voltage PT switch cabinet in a substation. Background Art

[0002] With the rapid development of the national economy, the scale of my country's power grid is constantly expanding, and the number of substations in operation is also increasing. In the power grid system, the high-voltage switchgear is the equipment that connects the low-voltage side of the substation with the distribution network. Its normal operation is directly related to the reliable supply of electricity to users. The high-voltage switch PT cabinet on the low-voltage side can collect bus voltage signals, which can be used to monitor the operation of the low-voltage side of the substation, identify station or line faults, and start tripping protection.

[0003] During the operation of the high-voltage switch PT cabinet, affected by external overvoltage, ferromagnetic resonance, local defects in internal insulation and other factors, PT failures are prone to occur, or system resonance overvoltage is caused, which affects the safety of the equipment and the stable operation of the system. At present, the low-voltage side of the power grid system generally does not have a fault recording system installed, nor does it have effective real-time monitoring, identification, and elimination methods for overvoltage. The detuning device used has poor overvoltage category recognition ability and insufficient sampling accuracy, and the actual detuning effect is not ideal. It is difficult to find out the cause after the failure occurs, and it is difficult to carry out targeted prevention and improvement. For the defects of the switch cabinet PT body, it can only be inspected regularly through live detection, but the defect detection effect is not timely and the detection result has a large deviation. In addition, the traditional PT cabinet fault detection method is single, the judgment accuracy is low, and it lacks the ability to comprehensively judge and analyze the linkage of multi-source parameters, or it requires a large amount of manual intervention in the later stage, the response speed is slow, and the power outage time is long. In summary, in order to improve the fault detection, monitoring and automatic detuning capabilities of the high-voltage switch PT cabinet, it is urgent to study a device and method for intelligent early warning and suppression of the operation risk of the high-voltage switch PT cabinet. Summary of the invention

[0004] Technical problem to be solved by the present invention: In view of the above-mentioned problems in the prior art and the poor risk warning and fault elimination capability of the high-voltage switch PT cabinet, a high-voltage switch PT cabinet operation monitoring device and an application method thereof are provided. The present invention aims to solve the problems of frequent overvoltage failures, difficulty in detuning, and difficulty in monitoring internal faults of the high-voltage PT cabinet. It can efficiently, accurately and comprehensively monitor the operating status of the PT cabinet, and can be used to realize intelligent fault elimination of specific operating defects.

[0005] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0006] A high-voltage switch PT cabinet operation monitoring device comprises a PT neutral point current detection unit, an overvoltage monitoring unit, an ultrasonic partial discharge monitoring unit and a control unit, wherein the output ends of the PT neutral point current detection unit, the overvoltage monitoring unit and the ultrasonic partial discharge monitoring unit are respectively connected to the control unit.

[0007] Optionally, the PT neutral point current detection unit is a current transformer TA, which is installed at the tail of the primary harmonic elimination module of the high-voltage switch PT cabinet, and collects the neutral point current in a core-through manner and outputs it to the control unit.

[0008] Optionally, the overvoltage monitoring unit includes a broadband sensing insulator and a secondary voltage divider circuit. The broadband sensing insulator is placed in a high-voltage switch PT cabinet, and the high-voltage side of the broadband sensing insulator is connected to the lead-out copper bus at the lower end of the isolation trolley of the high-voltage switch PT cabinet, and the low-voltage side outputs a low voltage signal to the control unit through the secondary voltage divider circuit.

[0009] Optionally, the ultrasonic partial discharge monitoring unit includes an ultrasonic sensor unit and a preamplifier unit, the ultrasonic sensor unit is installed in a high-voltage switch PT cabinet, and the output end of the ultrasonic sensor unit outputs an ultrasonic sensor signal to the control unit through the preamplifier unit.

[0010] Optionally, the control unit includes a microprocessor, a human-machine module, a communication module and a power module, the output ends of the PT neutral point current detection unit, the overvoltage monitoring unit and the ultrasonic partial discharge monitoring unit are respectively connected to the input end of the microprocessor, the microprocessor is respectively connected to the human-machine module and the communication module, and the output end of the power module is respectively connected to the microprocessor, the human-machine module and the communication module.

[0011] Optionally, the control output end of the microprocessor is also connected to the control end of the primary detuning module or the secondary detuning module of the high-voltage switch PT cabinet to start the primary detuning module or the secondary detuning module of the high-voltage switch PT cabinet to perform detuning.

[0012] In addition, the present invention also provides an application method of the above-mentioned high-voltage switch PT cabinet operation monitoring device, including the steps of PT neutral point current monitoring:

[0013] A1) obtaining the actual value I of the PT neutral point current by detecting the PT neutral point current detection unit;

[0014] A2) determining whether the actual value I of the PT neutral point current is greater than the preset PT neutral point current setting value I0; if so, issuing an alarm signal, and simultaneously starting the resonance active suppression module to perform detuning, and jumping to step A3);

[0015] A3) After the detuning starts for a period of time T1, determine whether the detuning is successful. If the detuning is successful, remove the alarm signal and the process ends; otherwise, jump to step A2).

[0016] Optionally, the step of ultrasonic monitoring is also included:

[0017] B1) detecting the actual value V of the amplitude-frequency coefficient of the ultrasonic signal through the ultrasonic partial discharge monitoring unit;

[0018] B2) Determine whether the actual value V of the amplitude-frequency coefficient is greater than the preset amplitude-frequency coefficient calibration value V0. If not, determine that the ultrasonic signal is a normal signal and the process ends; otherwise, further determine whether the ultrasonic signal is a partial discharge signal. If not, report an abnormal vibration alarm signal and the process ends; if it is a partial discharge signal, determine whether there is an overvoltage signal. If there is an overvoltage signal, determine that the partial discharge signal is an overvoltage PT partial discharge signal. If there is no overvoltage signal, determine that the partial discharge signal is a PT partial discharge abnormal signal, report an alarm signal and the process ends;

[0019] Among them, judging whether there is an overvoltage signal in step B2) means: collecting voltage data through the overvoltage monitoring unit, judging the voltage amplitude in the voltage data to determine whether there is an overvoltage, if the voltage amplitude is greater than the preset threshold, it is judged that there is an overvoltage signal, otherwise it is judged that there is no overvoltage signal.

[0020] Optionally, when the condition that the actual value I of the PT neutral point current is greater than the preset PT neutral point current setting value I0 in step A2) is not established, the step of further performing the ultrasonic monitoring is also included.

[0021] Optionally, the method further includes the step of performing overvoltage detection:

[0022] C1) collecting voltage data through an overvoltage monitoring unit;

[0023] C2) judging the voltage amplitude in the voltage data to determine whether there is an overvoltage, if there is no overvoltage, the process ends; otherwise, identifying the overvoltage type according to the voltage spectrum;

[0024] C3) extracting the actual value G of the amplitude-frequency ratio based on the voltage data, determining whether the actual value G of the amplitude-frequency ratio is greater than the preset amplitude-frequency ratio calibration value G0, if so, determining that the overvoltage is a resonant overvoltage, issuing a resonant overvoltage warning signal, and starting the resonance active suppression module to eliminate the resonance, and jumping to step C4); if not, issuing an overvoltage warning signal of the voltage type identified in step C2), and the process ends;

[0025] C4) After the detuning starts for a period of time T1, determine whether the detuning is successful. If the detuning is successful, remove the alarm signal and the process ends; otherwise, jump to step C3).

[0026] Compared with the prior art, the present invention has the following advantages: the high-voltage switch PT cabinet operation monitoring device of the present invention comprises a PT neutral point current detection unit, an overvoltage monitoring unit, an ultrasonic partial discharge monitoring unit and a control unit, the output ends of the PT neutral point current detection unit, the overvoltage monitoring unit and the ultrasonic partial discharge monitoring unit are respectively connected to the control unit, and can be used to realize automatic collection, comparison and comprehensive analysis of multi-dimensional signals of the PT cabinet, and combined with the monitoring of three signals of PT neutral point current, overvoltage and ultrasonic partial discharge, it can realize all-round monitoring of the operation risk of the high-voltage switch PT cabinet, can solve the problems of frequent overvoltage faults, difficult detuning and difficult internal fault monitoring of the high-voltage switch PT cabinet, can efficiently, accurately and comprehensively monitor the operation status of the high-voltage switch PT cabinet, and can be used to realize intelligent elimination of specific operation defects. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 Schematic diagram of the structure of the device according to the embodiment of the present invention.

[0028] Figure 2 Schematic diagram of the basic flow of the method of the embodiment of the present invention.

[0029] Legend: 1. PT neutral point current detection unit; 2. Overvoltage monitoring unit; 21. Broadband sensing insulator; 22. Secondary voltage divider circuit; 3. Ultrasonic partial discharge monitoring unit; 31. Ultrasonic sensing unit; 32. Preamplifier unit; 4. Control unit; 41. Microprocessor; 42. Human-machine module; 43. Communication module; 44. Power module. DETAILED DESCRIPTION

[0030] like Figure 1 As shown, the high-voltage switch PT cabinet operation monitoring device of this embodiment includes a PT neutral point current detection unit 1, an overvoltage monitoring unit 2, an ultrasonic partial discharge monitoring unit 3 and a control unit 4, and the output ends of the PT neutral point current detection unit 1, the overvoltage monitoring unit 2, and the ultrasonic partial discharge monitoring unit 3 are respectively connected to the control unit 4. The PT neutral point current detection unit 1 can realize the PT neutral point current detection of the high-voltage switch PT cabinet, the overvoltage monitoring unit 2 can realize the overvoltage monitoring of the high-voltage switch PT cabinet, and the ultrasonic partial discharge monitoring unit 3 can realize the ultrasonic partial discharge monitoring of the high-voltage switch PT cabinet, which can be used to realize the automatic collection, comparison, and comprehensive analysis of the multi-dimensional signals of the PT cabinet. Combined with the monitoring of the three signals of PT neutral point current, overvoltage, and ultrasonic partial discharge, the operation risk of the high-voltage switch PT cabinet can be fully monitored, which can solve the problems of frequent overvoltage faults, difficult detuning, and difficult internal fault monitoring of the high-voltage switch PT cabinet, and can efficiently, accurately, and comprehensively monitor the operation status of the high-voltage switch PT cabinet, and can be used to realize the intelligent elimination of specific operation defects.

[0031] The PT neutral point current detection unit 1 is used to monitor the discharge current of the detuning device as the PT neutral point current. In this embodiment, the PT neutral point current detection unit 1 is a current transformer TA, which is installed at the tail of the primary detuning module of the high-voltage switch PT cabinet, and uses a core-through method to collect the neutral point current and output it to the control unit 4, which can meet the requirements of balance characteristics, anti-interference and linearity. In this embodiment, the measurement range of the current transformer TA is 50mA-1A, the ratio difference is less than or equal to 0.2%, the phase difference is less than or equal to 30 minutes, and the rated output is 0-1V (AC), which can effectively measure the zero-sequence current of the PT neutral point.

[0032] The overvoltage monitoring unit 2 can collect overvoltage signals for overvoltage identification and countermeasure analysis. Figure 1 As shown, the overvoltage monitoring unit 2 of this embodiment includes a broadband sensing insulator 21 and a secondary voltage dividing circuit 22. The broadband sensing insulator 21 is placed in the high-voltage switch PT cabinet, and the high-voltage side of the broadband sensing insulator 21 is connected to the lead-out copper busbar at the lower end of the isolation trolley of the high-voltage switch PT cabinet, and the low-voltage side outputs a low-voltage signal to the control unit 4 through the secondary voltage dividing circuit 22. The broadband sensing insulator 21 is a non-traditional voltage transformer that can cover the measurement and protection range, and can realize the integration of supporting insulation and broadband overvoltage monitoring functions. It uses film capacitors or ceramic capacitors, and can meet the requirements of 10 years of reliable operation and unchanged measurement accuracy. It can meet all the error requirements of its rated primary voltage measurement level and protection level. The rated primary voltage includes the rated phase voltage and the rated zero-sequence voltage, and the standard value is The rated secondary phase voltage standard value is The standard value of the rated secondary zero-sequence voltage is 6.5V / 3.

[0033] The ultrasonic partial discharge monitoring unit 3 is used to realize continuous ultrasonic partial discharge monitoring inside the PT cabinet, and the monitoring result can be used to determine whether there is a partial discharge signal caused by abnormal insulation defects inside the PT cabinet. Figure 1 As shown, the ultrasonic partial discharge monitoring unit 3 of this embodiment includes an ultrasonic sensor unit 31 and a preamplifier unit 32. The ultrasonic sensor unit 31 is installed in the high-voltage switch PT cabinet, and the output end of the ultrasonic sensor unit 31 outputs the ultrasonic sensor signal to the control unit 4 through the preamplifier unit 32. In this embodiment, the ultrasonic sensor unit 31 adopts an industrial-grade high-precision ultrasonic probe, with a high-efficiency amplification and filtering circuit, with high sensitivity and rapid response, and can avoid the vibration frequency band of the running equipment, and effectively collect partial discharge ultrasonic signals, including the number of partial discharge pulses and pulse amplitude. By studying the relationship between the time domain phase, the number of pulses and the measurement threshold under different defect models, combining a variety of anti-interference algorithms, eliminating field interference signals, and warning of PT cabinet insulation faults, the data can be uploaded to the host computer through the 485 bus.

[0034] like Figure 1As shown, the control unit 4 of this embodiment includes a microprocessor 41, a human-machine module 42, a communication module 43 and a power module 44. The output ends of the PT neutral point current detection unit 1, the overvoltage monitoring unit 2 and the ultrasonic partial discharge monitoring unit 3 are respectively connected to the input ends of the microprocessor 41, the microprocessor 41 is respectively connected to the human-machine module 42 and the communication module 43, and the output end of the power module 44 is respectively connected to the microprocessor 41, the human-machine module 42 and the communication module 43.

[0035] like Figure 1 As shown, the control output end of the microprocessor 41 of this embodiment is also connected to the control end of the primary detuning module or the secondary detuning module of the high-voltage switch PT cabinet to start the primary detuning module or the secondary detuning module (not shown in the figure) of the high-voltage switch PT cabinet to perform detuning, so that active detuning can be performed according to the monitoring results.

[0036] like Figure 2 As shown, this embodiment also provides an application method of the above-mentioned high-voltage switch PT cabinet operation monitoring device, including the steps of PT neutral point current monitoring:

[0037] A1) obtaining the actual value I of the PT neutral point current by detecting the PT neutral point current detection unit 1;

[0038] A2) determining whether the actual value I of the PT neutral point current is greater than the preset PT neutral point current setting value I0, and if so, issuing an alarm signal, and simultaneously starting the resonance active suppression module 45 to perform detuning, and jumping to step A3);

[0039] A3) After the detuning starts for a period of time T1, determine whether the detuning is successful. If the detuning is successful, remove the alarm signal and the process ends; otherwise, jump to step A2).

[0040] In this embodiment, judging whether the detuning is successful means performing voltage detection through the overvoltage monitoring unit 2 and judging whether the resonant overvoltage still exists. If the resonant overvoltage exists, it is judged that the detuning is unsuccessful, otherwise it is judged that the detuning is successful.

[0041] As an optional implementation, sending an alarm signal in this embodiment refers to sending an alarm signal to the monitoring background through the network. In addition, other forms of sending alarm signals can be used as needed, including to an alarm or other output device, or other physical nodes in the network or virtual nodes including network users.

[0042] In addition, as an optional implementation, when the PT neutral point current actual value I is greater than the preset PT neutral point current setting value I0 in step A2) of this embodiment, a further ultrasonic monitoring step is also included. By starting the ultrasonic detection device for forced collection, and combining whether there is overvoltage, the ultrasonic partial discharge signal is automatically divided into overvoltage PT partial discharge and PT partial discharge abnormality in the system background and an alarm is issued.

[0043] like Figure 2 As shown, this embodiment also includes the step of ultrasonic monitoring:

[0044] B1) detecting the actual value V of the amplitude-frequency coefficient of the ultrasonic signal by the ultrasonic partial discharge monitoring unit 3; the actual value V of the amplitude-frequency coefficient refers to the amplitude at a specified frequency, and the specified frequency may be a base frequency, a distribution or a multiple frequency, and may be expressed as follows using a function expression:

[0045]

[0046] In the above formula, V1 is the amplitude at the specified frequency f, f t Can be base frequency, distribution or multiplication;

[0047] B2) Determine whether the actual value V of the amplitude-frequency coefficient is greater than the preset amplitude-frequency coefficient calibration value V0. If not, determine that the ultrasonic signal is a normal signal and the process ends; otherwise, further determine whether the ultrasonic signal is a partial discharge signal. If not, report an abnormal vibration alarm signal and the process ends; if it is a partial discharge signal, determine whether there is an overvoltage signal. If there is an overvoltage signal, determine that the partial discharge signal is an overvoltage PT partial discharge signal. If there is no overvoltage signal, determine that the partial discharge signal is a PT partial discharge abnormal signal, report an alarm signal and the process ends;

[0048] In this embodiment, determining whether there is an overvoltage signal in step B2) means: collecting voltage data through the overvoltage monitoring unit 2, determining the voltage amplitude in the voltage data to determine whether there is an overvoltage; if the voltage amplitude is greater than a preset threshold, determining that there is an overvoltage signal; otherwise determining that there is no overvoltage signal.

[0049] In this embodiment, to determine whether the ultrasonic signal is a partial discharge signal, one of the following methods may be selected as needed:

[0050] Method 1: Match the ultrasonic signal with the preset expert library spectrum features. If there is no match, it is determined not to be a partial discharge signal. If there is a match, it is determined to be a partial discharge signal.

[0051] Method 2: Using a machine learning classification model to determine whether an ultrasonic signal is a partial discharge signal. In this embodiment, when a machine learning classification model is used to determine whether an ultrasonic signal is a partial discharge signal, the ultrasonic signal features used include: (1) ultrasonic amplitude range Ep. The ultrasonic amplitude can effectively distinguish between noise and partial discharge signals. The amplitude of the partial discharge signal should be within a specific amplitude range. Through machine learning actual cases, the accuracy of this range is increased; (2) ultrasonic signal waveform period T. Through case study of the ultrasonic signal waveform period T, the accuracy of judging the type of partial discharge through the period can be increased; (3) ultrasonic signal amplitude-frequency coefficient V. The ultrasonic signal amplitude-frequency coefficient V can be used to identify the correlation between signals such as ultrasonic amplitude and period, and the accuracy of correlation identification can be improved through machine learning.

[0052] like Figure 2 As shown, this embodiment also includes the step of performing overvoltage detection:

[0053] C1) collecting voltage data through the overvoltage monitoring unit 2;

[0054] C2) judging the voltage amplitude in the voltage data to determine whether there is an overvoltage, if there is no overvoltage, the process ends; otherwise, identifying the overvoltage type according to the voltage spectrum;

[0055] C3) extracting the actual value G of the amplitude-frequency ratio based on the voltage data, determining whether the actual value G of the amplitude-frequency ratio is greater than the preset amplitude-frequency ratio calibration value G0, if so, determining that the overvoltage is a resonant overvoltage, issuing a resonant overvoltage warning signal, and starting the resonance active suppression module 45 to eliminate the resonance, and jumping to step C4); if not, issuing an overvoltage warning signal of the voltage type identified in step C2), and the process ends;

[0056] C4) After the detuning starts for a period of time T1, it is determined whether the detuning is successful. If the detuning is successful, the alarm signal is released and the process ends; otherwise, the process jumps to step C3). When G>G0, it is determined to be a resonant overvoltage, an overvoltage warning signal is sent to the background system, and the PT neutral point current detection is linked to start the resonance active suppression module 45, and the same process as the PT neutral point current monitoring is performed according to the detuning effect.

[0057] In this embodiment, to determine whether the ultrasonic signal is a partial discharge signal, one of the following methods may be selected as needed:

[0058] Method 1: Identifying the overvoltage type based on the voltage spectrum refers to matching the voltage spectrum with the preset expert library spectrum features to identify the overvoltage type.

[0059] Method 2: Using a machine learning classification model to identify the type of overvoltage based on the voltage spectrum. In this embodiment, when using a machine learning classification model to identify the type of overvoltage based on the voltage spectrum, the ultrasonic signal features used include: (1) waveform parameter fz. Frequency is a key waveform parameter fz for overvoltage identification. The actual frequencies of different overvoltage waveforms such as high frequency, base frequency, and multiple frequency fluctuate within a certain range and may even overlap. Through the recognition and learning of the waveform parameter fz, the accuracy of the machine in identifying the type of overvoltage based on frequency is gradually increased. (2) Amplitude-frequency coefficient V. The equipment failure rate under a specific amplitude-frequency coefficient, and the correlation between amplitude and equipment failure rate; for example, waveform fitting learning, comparative analysis of highly similar historical waveforms, to increase the accuracy of judgment. (3) Waveform cycle time T. There are differences in the duration period T of different overvoltages. The waveform stabilization time can be obtained through the waveform cycle time T. Through case learning, the machine's autonomous judgment ability is enhanced.

[0060] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present application may take the form of a computer program product implemented on one or more computer-readable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program codes. The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, may be implemented by computer program instructions. These computer program instructions may 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 functions in the process. Figure 1 A process or multiple processes and / or boxes Figure 1 These computer program instructions can also be stored in a computer-readable memory that can guide a computer or other programmable data processing device to work in a specific way, so that the instructions stored in the computer-readable memory produce a product including an instruction device, which implements the functions specified in the process. Figure 1 A process or multiple processes and / or boxes Figure 1These computer program instructions can also be loaded onto a computer or other programmable data processing device, so that a series of operation steps are executed on the computer or other programmable device to produce a computer-implemented process, so that the instructions executed on the computer or other programmable device provide for implementing the process in the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0061] The above is only a preferred embodiment of the present invention, and the protection scope of the present invention is not limited to the above embodiments. All technical solutions under the concept of the present invention belong to the protection scope of the present invention. It should be pointed out that for ordinary technicians in this technical field, some improvements and modifications without departing from the principle of the present invention should also be regarded as the protection scope of the present invention.

Claims

1. An application method of a high-voltage switch PT cabinet operation monitoring device, characterized in that: The high-voltage switch PT cabinet operation monitoring device comprises a PT neutral point current detection unit (1), an overvoltage monitoring unit (2), an ultrasonic partial discharge monitoring unit (3) and a control unit (4), wherein the output ends of the PT neutral point current detection unit (1), the overvoltage monitoring unit (2) and the ultrasonic partial discharge monitoring unit (3) are respectively connected to the control unit (4); the application method comprises the steps of ultrasonic monitoring: B1) detecting an actual value V of the amplitude-frequency coefficient of the ultrasonic signal by means of an ultrasonic partial discharge monitoring unit (3); B2) Determine whether the actual value V of the amplitude-frequency coefficient is greater than the preset amplitude-frequency coefficient calibration value V0. If not, determine that the ultrasonic signal is a normal signal and the process ends; otherwise, further determine whether the ultrasonic signal is a partial discharge signal. If not, report an abnormal vibration alarm signal and the process ends; if it is a partial discharge signal, determine whether there is an overvoltage signal. If there is an overvoltage signal, determine that the partial discharge signal is an overvoltage PT partial discharge signal. If there is no overvoltage signal, determine that the partial discharge signal is a PT partial discharge abnormal signal, report an alarm signal and the process ends; Wherein, judging whether there is an overvoltage signal in step B2) means: collecting voltage data through the overvoltage monitoring unit (2), judging the voltage amplitude in the voltage data to judge whether there is an overvoltage, if the voltage amplitude is greater than a preset threshold, judging that there is an overvoltage signal, otherwise judging that there is no overvoltage signal.

2. The application method of the high-voltage switch PT cabinet operation monitoring device according to claim 1 is characterized in that: The PT neutral point current detection unit (1) is a current transformer TA, which is installed at the tail of a primary detuning module of a high-voltage switch PT cabinet and collects neutral point current in a core-penetrating manner and outputs it to a control unit (4).

3. The application method of the high-voltage switch PT cabinet operation monitoring device according to claim 2 is characterized in that: The overvoltage monitoring unit (2) comprises a broadband sensing insulator (21) and a secondary voltage dividing circuit (22); the broadband sensing insulator (21) is arranged in a high-voltage switch PT cabinet, and the high-voltage side of the broadband sensing insulator (21) is connected to the lead-out copper busbar at the lower end of the isolation trolley of the high-voltage switch PT cabinet, and the low-voltage side outputs a low-voltage signal to the control unit (4) via the secondary voltage dividing circuit (22).

4. The application method of the high-voltage switch PT cabinet operation monitoring device according to claim 3 is characterized in that: The ultrasonic partial discharge monitoring unit (3) comprises an ultrasonic sensor unit (31) and a preamplifier unit (32); the ultrasonic sensor unit (31) is installed in a high-voltage switch PT cabinet; the output end of the ultrasonic sensor unit (31) outputs an ultrasonic sensor signal to a control unit (4) via the preamplifier unit (32).

5. The application method of the high-voltage switch PT cabinet operation monitoring device according to claim 4 is characterized in that: The control unit (4) comprises a microprocessor (41), a human-machine module (42), a communication module (43) and a power module (44); the output ends of the PT neutral point current detection unit (1), the overvoltage monitoring unit (2) and the ultrasonic partial discharge monitoring unit (3) are respectively connected to the input end of the microprocessor (41); the microprocessor (41) is respectively connected to the human-machine module (42) and the communication module (43); and the output end of the power module (44) is respectively connected to the microprocessor (41), the human-machine module (42) and the communication module (43).

6. The application method of the high-voltage switch PT cabinet operation monitoring device according to claim 5 is characterized in that: The control output end of the microprocessor (41) is also connected to the control end of the primary detuning module or the secondary detuning module of the high-voltage switch PT cabinet to start the primary detuning module or the secondary detuning module of the high-voltage switch PT cabinet to perform detuning.

7. The application method of the high-voltage switch PT cabinet operation monitoring device according to any one of claims 1 to 6, characterized in that: It also includes the steps of PT neutral point current monitoring: A1) obtaining the actual value I of the PT neutral point current by detecting the PT neutral point current detection unit (1); A2) determining whether the actual value I of the PT neutral point current is greater than the preset PT neutral point current setting value I0; if so, issuing an alarm signal, and simultaneously starting the resonance active suppression module (45) to perform detuning, and jumping to execute step A3); A3) After the detuning starts for T1, determine whether the detuning is successful. If the detuning is successful, the alarm signal is cleared and the process ends. Otherwise, jump to step A2).

8. The application method of the high-voltage switch PT cabinet operation monitoring device according to claim 7 is characterized in that: When the condition that the actual value I of the PT neutral point current is greater than the preset PT neutral point current setting value I0 in step A2) is not established, the method further includes the step of performing the ultrasonic monitoring.

9. The application method of the high-voltage switch PT cabinet operation monitoring device according to claim 8 is characterized in that: It also includes the steps for overvoltage detection: C1) collecting voltage data through the overvoltage monitoring unit (2); C2) Determine whether there is overvoltage by judging the voltage amplitude in the voltage data. If there is no overvoltage, the process ends; otherwise, identify the overvoltage type according to the voltage spectrum; C3) extracting the actual value G of the amplitude-frequency ratio based on the voltage data, determining whether the actual value G of the amplitude-frequency ratio is greater than the preset amplitude-frequency ratio calibration value G0; if so, determining that the overvoltage is a resonant overvoltage, issuing a resonant overvoltage warning signal, and starting the resonance active suppression module (45) to eliminate the resonance, and jumping to step C4); if not, issuing an overvoltage warning signal of the voltage type identified in step C2), and the process ends; C4) After the detuning starts for T1, determine whether the detuning is successful. If the detuning is successful, the alarm signal is cleared and the process ends. Otherwise, jump to step C3).

Images