Converter transformer grid-side bushing regional partial discharge detection system and method based on multiple means

Abstract

The present invention discloses a partial discharge detection system and method for the bushing area on the grid side of a converter transformer based on multiple means, including a partial discharge monitoring sensor, a live detection device, a signal acquisition module and a signal analysis and processing module. The partial discharge monitoring sensor detects the signal of the bushing area on the grid side of the converter transformer, and the signal acquisition module acquires the above signal; the signal analysis and processing module compares and analyzes the acquired signal with the spectrum of the standard partial discharge signal, determines whether the signal is an abnormal signal, and determines whether the abnormal signal is located inside or outside the bushing area; after the abnormal signal is monitored, the signal collected by the live detection device is used to check whether there is an interference signal in the signal, analyze and diagnose the discharge signal characteristics in the signal, and locate the source of the discharge signal. The present invention can carry out online monitoring and live detection of partial discharge in the bushing area on the grid side of the converter transformer in operation, effectively eliminate interference signals, and accurately locate the source of the signal.

Description

Technical Field

[0001] The present invention belongs to the technical field of partial discharge detection in a bushing region on the grid side of an ultra-high voltage converter transformer, and in particular relates to a partial discharge detection and analysis method in a bushing region on the grid side of a converter transformer based on a combination of multiple means. Background Art

[0002] The grid-side bushing of the converter transformer in the UHV converter station (hereinafter referred to as the converter transformer grid-side bushing) is located at the connection position between the grid-side winding of the converter transformer and the AC side system, and its position is crucial. The operating reliability of the converter transformer grid-side bushing is directly related to the safe operation of the relevant equipment of the entire valve group. If a single converter transformer grid-side bushing fails in operation, it may cause the valve group to be locked and six converter transformers to stop operating at the same time. Therefore, it is of great significance to carry out effective detection and accurate analysis of the internal discharge defects of the converter transformer grid-side bushing in operation.

[0003] The bushing area on the grid side of the converter transformer includes the bushing on the grid side of the converter transformer and the bushing riser on the grid side. Currently, there is no targeted means of detecting partial discharge with electricity. The commonly used online monitoring methods are ultra-high frequency method, ultrasonic method and high frequency method. However, the online monitoring device for partial discharge of the grid-side bushing currently in operation is weak in function, lacks anti-interference and signal source positioning functions, and is far from meeting the requirements of monitoring and analysis. Some high-frequency partial discharge online monitoring devices used in the grid are based on the modification of the bushing end screen structure and the installation of high-frequency current sensors to achieve partial discharge monitoring. This method will destroy the sealing and grounding integrity of the bushing end screen, bringing safety hazards. The inspection and judgment of the operating status of the bushing on the grid side of the converter transformer is currently mainly judged by mechanical structure inspection and bushing oil sampling analysis during power outages. The existing partial discharge detection technology for the bushing on the grid side of the converter transformer is weak in function and inefficient, and cannot achieve effective detection and accurate diagnosis of internal discharge defects of the bushing on the grid side of the converter transformer. Summary of the invention

[0004] The purpose of the present invention is to provide a system and method for detecting partial discharge in the bushing area on the grid side of a converter transformer based on multiple means, which can realize interference signal troubleshooting, signal source location, and live detection review and confirmation without power outage or modification of the bushing structure, thereby helping to improve the accuracy of partial discharge detection and analysis in the bushing area on the grid side of the converter transformer and ensure the safe operation of the converter transformer and adjacent equipment.

[0005] To achieve this purpose, the present invention is a multi-means-based partial discharge detection system for the bushing area on the grid side of the converter transformer, comprising a partial discharge monitoring sensor, a live detection device, a signal acquisition module and a signal analysis and processing module. The partial discharge monitoring sensor comprises an ultrasonic sensor, a UHF sensor and a high-frequency current sensor. The partial discharge monitoring sensor is used to detect the signal of the bushing area on the grid side of the converter transformer. The signal of the bushing area on the grid side of the converter transformer comprises an ultrasonic signal, a UHF signal and a high-frequency current signal. The signal acquisition module is used to collect the signal of the bushing area on the grid side of the converter transformer detected by the partial discharge monitoring sensor. The signal analysis and processing module The module is used to compare and analyze the signal of the bushing area on the converter transformer grid side with the spectrum of the standard partial discharge signal, determine whether the signal of the bushing area on the converter transformer grid side is an abnormal signal, and distinguish whether the abnormal signal is inside or outside the bushing area. After the signal analysis and processing module determines that an abnormal signal is monitored, disconnect the connection line between the signal acquisition module and the partial discharge monitoring sensor, connect the live detection device to the partial discharge monitoring sensor, and collect the signal detected by the partial discharge monitoring sensor, check whether there is an interference signal in the detected signal, analyze and diagnose the discharge signal characteristics in the detected signal, and locate the discharge signal source.

[0006] A method for detecting partial discharge in bushing area on the grid side of a converter transformer based on multiple means, comprising the following steps:

[0007] Step S1, a partial discharge monitoring sensor detects a signal from a bushing area on the grid side of a converter transformer, wherein the signal from the bushing area on the grid side of the converter transformer comprises an ultrasonic signal, an ultra-high frequency signal and a high-frequency current signal, and a signal acquisition module acquires the signal from the bushing area on the grid side of the converter transformer detected by the partial discharge monitoring sensor;

[0008] Step S2, the signal analysis and processing module compares and analyzes the signal of the bushing area on the grid side of the converter transformer and the spectrum of the standard partial discharge signal, determines whether the signal of the bushing area on the grid side of the converter transformer is an abnormal signal, and determines whether the abnormal signal is inside or outside the bushing area;

[0009] Step S3: after the signal analysis and processing module determines that an abnormal signal is detected, disconnect the connection line between the signal acquisition module and the partial discharge monitoring sensor, connect the charged detection device to the partial discharge monitoring sensor, and collect the signal detected by the partial discharge monitoring sensor, check whether there is an interference signal in the detected signal, analyze and diagnose the discharge signal characteristics in the detected signal, and locate the discharge signal source.

[0010] The beneficial effects of the present invention are as follows: the present invention can carry out online monitoring and live detection of partial discharge in the bushing area on the grid side of the converter transformer in operation, effectively eliminate interference signals, and accurately locate the signal source. The potential safety hazards existing inside the bushing area on the grid side of the converter transformer in operation can be discovered in advance to prevent accidents. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 It is a schematic diagram of the process of the present invention;

[0012] Figure 2 It is a schematic diagram of the system structure of the present invention;

[0013] Figure 3 The schematic diagrams of the installation position of the ultrasonic sensor of the present invention are the front view and the top view;

[0014] Figure 4 The schematic diagrams of the installation position of the UHF sensor of the present invention are the front view and the top view;

[0015] Figure 5 This is a schematic diagram of the installation position of the high-frequency current sensor of the present invention;

[0016] Among them, 1-partial discharge monitoring sensor, 2-live detection equipment, 3-signal acquisition module, 4-signal analysis and processing module, 12-ultrasonic sensor, 13-ultra-high frequency sensor, 14-high frequency current sensor. DETAILED DESCRIPTION

[0017] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments:

[0018] A partial discharge detection system for bushing area on the grid side of converter transformer based on multiple means, such as Figures 1 to 5As shown, it includes a partial discharge monitoring sensor 1, a live detection device 2, a signal acquisition module 3, and a signal analysis and processing module 4. The partial discharge monitoring sensor 1 includes A ultrasonic sensors 12, B ultra-high frequency sensors 13, and C high-frequency current sensors 14, wherein A≥6, B≥3, and C≥2. The partial discharge monitoring sensor 1 is used to detect the signal of the bushing area on the converter transformer grid side. The signal of the bushing area on the converter transformer grid side includes an ultrasonic signal, an ultra-high frequency signal, and a high-frequency current signal. The signal acquisition module 3 is used to collect the signal of the bushing area on the converter transformer grid side detected by the partial discharge monitoring sensor 1. The signal analysis and processing module 4 is used to Compare and analyze the signal of the bushing area on the converter transformer grid side with the spectrum of the standard partial discharge signal, determine whether the signal of the bushing area on the converter transformer grid side is an abnormal signal, and distinguish whether the abnormal signal is inside or outside the bushing area. After the signal analysis and processing module 4 determines that an abnormal signal is detected, disconnect the connection line between the signal acquisition module 3 and the partial discharge monitoring sensor 1, connect the live detection device 2 to the partial discharge monitoring sensor 1, and collect the signal detected by the partial discharge monitoring sensor 1, find out whether there is an interference signal in the detected signal, analyze and diagnose the discharge signal characteristics in the detected signal, and locate the discharge signal source.

[0019] The frequency range of the above-mentioned ultra-high frequency sensor is 300-3000 MHz, and the frequency range of the high frequency current sensor is 3-30 MHz.

[0020] In the above technical solution, the A ultrasonic sensors 12 are used to monitor the ultrasonic signal and are installed on the surface of the casing lifting seat on the converter transformer network side. The A ultrasonic sensors 12 are grouped into three ultrasonic sensors, and each group of ultrasonic sensors is installed on a circular plane with the center of the bottom surface of the lifting seat as the origin. The three sensors on each circular plane are distributed at equal angles along the circumference, and the center interval of the circular plane where each group of ultrasonic sensors is located is h. The purpose of this design is to facilitate positioning, and the symmetrical equal-angle arrangement can reduce the workload of measuring the sensor coordinate values.

[0021] In the above technical solution, the B UHF sensors 13 include two detection channel UHF sensors and one noise channel UHF sensor. The detection channel UHF sensor is used to monitor the local discharge signal inside the bushing area on the converter transformer grid side, and the noise channel UHF sensor is used to monitor the noise interference signal in the surrounding environment of the bushing on the converter transformer grid side; the two detection channel UHF sensors are used for positioning, and the one noise channel UHF sensor is used to detect signals in the external environment for auxiliary analysis.

[0022] The C high-frequency current sensors 14 include one detection channel high-frequency current sensor and one noise channel high-frequency current sensor. The detection channel high-frequency current sensor is used to monitor the local discharge signal inside the bushing area on the grid side of the converter transformer, and the noise channel high-frequency current sensor is used to monitor the interference signal in the surrounding environment of the bushing on the grid side of the converter transformer.

[0023] In the above technical solution, the B UHF sensors 13 are installed at the connection gap of the converter transformer network side bushing elevation seat, wherein the front faces of the two detection channel UHF sensors face the inside of the gap, and the connection line of the two detection channel UHF sensors is parallel to the axial center line of the converter transformer network side bushing. This design is convenient for subsequent positioning analysis and for measuring the coordinate values ​​of the detection channel UHF sensors; the front face of the one noise channel UHF sensor faces the external air of the elevation seat; after the UHF sensors are installed, the coordinate values ​​of the B UHF sensors 13 are measured and recorded for positioning needs;

[0024] The one detection channel high-frequency current sensor is installed on the equipotential connecting line of the lifting seat, and the one noise channel high-frequency current sensor is directly tied to the lifting seat.

[0025] In the above technical solution, the signal acquisition module 3 is installed near the converter transformer body, and is used to collect the signal detected by the partial discharge monitoring sensor 1, and collect and send it to the signal analysis and processing module 4. The signal line interface of the signal acquisition module 3 directly connected to the partial discharge monitoring sensor 1 adopts a BNC interface or an N-type interface for use by the live detection device 2.

[0026] In the above technical solution, the signal analysis and processing module 4 is used to display the monitored signal spectrum, and compare the monitored signal of the bushing area on the grid side of the converter transformer with the standard partial discharge signal spectrum to determine whether the signal of the bushing area on the grid side of the converter transformer is an abnormal signal. The specific method is:

[0027] Step S21, comparing the waveform characteristics and time difference relationship of the A ultrasonic sensors, determining whether the signal in the bushing area on the grid side of the converter transformer contains an abnormal signal, and determining whether the abnormal signal is a mechanical vibration signal;

[0028] Step S22, comparing the signals of the two detection channel UHF sensors and the one noise channel UHF sensor, and comparing them with the standard discharge signal spectrum, to determine whether the abnormal signal comes from inside or outside the bushing area on the converter transformer grid side;

[0029] Step S23, comparing the signals of the one detection channel high-frequency current sensor and the one noise channel high-frequency current sensor, and comparing them with the standard discharge signal spectrum, to determine whether the abnormal signal comes from inside or outside the bushing area on the converter transformer grid side.

[0030] Interference can be checked by the above method. The ultrasonic method used in step S21 is to check the interference signal by comparing the waveforms of multiple sensor channels. The ultra-high frequency method used in step S22 and the high frequency method used in step S23 are to eliminate interference by comparing the signal of the detection channel sensor with the signal of the noise channel sensor in the external environment.

[0031] In the above technical solution, the specific method of step S21 is:

[0032] When the signal waveform has the following characteristics, the abnormal signal is judged to be a partial discharge signal:

[0033] (1) The signal waveform is an exponentially decaying oscillating waveform, which conforms to the periodic characteristics and phase characteristics of the power frequency voltage, and the waveform is a periodic signal;

[0034] (2) The amplitudes of the signal waveforms monitored by the A ultrasonic sensor channels are not equal to each other, and the starting edge times of the signal waveforms are different;

[0035] When the signal waveform has the following characteristics, the abnormal signal is judged to be a mechanical vibration signal:

[0036] (1) The envelope of the signal waveform is a continuous spindle shape, which does not conform to the phase characteristics of the power frequency voltage;

[0037] (2) The starting edge times of the signal waveforms monitored by the A ultrasonic sensor channels are all the same.

[0038] The method adopted in step S21 is determined according to the structure of the bushing area on the grid side of the converter transformer. Ultrasonic method can be used to monitor partial discharge, and then the method described is used to determine whether the abnormal signal is a partial discharge signal or a mechanical vibration signal.

[0039] In the above technical solution, the specific method of step S22 is:

[0040] The abnormal signals detected by the UHF method and the HF method include partial discharge signals and external interference signals;

[0041] The conditions for determining that the abnormal signal originates from the inner area of ​​the bushing on the converter transformer grid side are: the signal spectrum characteristics of the UHF sensors of the two detection channels conform to the standard discharge signal spectrum, and the signal spectrum of the UHF sensor of the one noise channel does not conform to the standard discharge signal spectrum; or the signal spectra of the UHF sensors of the two detection channels and the UHF sensor of the one noise channel conform to the standard spectrum and the signal amplitudes of the UHF sensors of the two detection channels are greater than the signal amplitude of the UHF sensor of the one noise channel;

[0042] The conditions for determining that the abnormal signal originates from outside the bushing area on the converter transformer grid side are: the signal spectra of the two detection channel ultra-high frequency sensors do not conform to the standard discharge signal spectrum, or the signal spectra of the two detection channel ultra-high frequency sensors and the one noise channel ultra-high frequency sensor both conform to the standard discharge signal spectrum and the signal amplitudes of the two detection channel ultra-high frequency sensors are smaller than the signal amplitude of the one noise channel ultra-high frequency sensor.

[0043] In the above technical solution, the specific method of step S23 is:

[0044] The conditions for determining that the abnormal signal originates from the inner region of the bushing on the transformer grid side are: the signal spectrum characteristics of the high-frequency current sensor of the one detection channel conform to the standard discharge signal spectrum, and the signal spectrum of the high-frequency current sensor of the one noise channel does not conform to the standard discharge signal spectrum; or the signal spectra of the high-frequency current sensor of the one detection channel and the high-frequency current sensor of the one noise channel both conform to the standard spectrum and the signal amplitude of the high-frequency current sensor of the one detection channel is greater than the signal amplitude of the high-frequency current sensor of the one noise channel;

[0045] The conditions for determining that the abnormal signal originates from outside the bushing area on the converter transformer grid side are: the signal spectrum of the high-frequency current sensor of the one detection channel does not conform to the standard discharge signal spectrum, or the signal spectra of the high-frequency current sensor of the one detection channel and the high-frequency current sensor of the one noise channel both conform to the standard discharge signal spectrum and the signal amplitude of the high-frequency current sensor of the one detection channel is less than the signal amplitude of the high-frequency current sensor of the one noise channel.

[0046] The specific method of step S23 is a method commonly used on-site to determine whether the abnormal signal source is an internal signal or an external signal, which is obtained through long-term field experience accumulation.

[0047] In the above technical solution, the specific method of the live detection device 2 to detect interference signals is:

[0048] S31, at the signal acquisition module of the partial discharge online monitoring system of the bushing area on the converter transformer grid side, the live detection device 2 is connected to the partial discharge monitoring sensor 1, and the ultra-high frequency, ultrasonic and high frequency signals detected by the partial discharge monitoring sensor 1 are collected for comparative analysis;

[0049] S32. If it is determined in step S23 that the abnormal signal originates from outside the bushing area on the grid side of the converter transformer, the ultraviolet imager in the live detection device 2 may be used to detect the bushing elevation seat area on the grid side by adopting the ultraviolet imaging detection method to determine the location of the interference signal source and eliminate it;

[0050] S33: If it is determined in step S23 that the abnormal signal is located inside the bushing area on the converter transformer grid side, the position of the abnormal signal is determined by a signal source positioning method.

[0051] In the above technical solution, the signal source positioning method includes the acoustic-acoustic positioning method, the acoustic-electric positioning method and the ultra-high frequency time difference positioning method;

[0052] When at least four ultrasonic sensors 12 receive the discharge signal at the same time, the sound-to-sound positioning method is used. When at least three ultrasonic sensors 12 and one detection channel ultra-high frequency sensor or one detection channel high-frequency current sensor receive the discharge signal at the same time, the sound-to-electric positioning method is used. When two detection channel ultra-high frequency sensors receive the discharge signal at the same time, the ultra-high frequency time difference positioning method is used.

[0053] A method for detecting partial discharge in bushing area on the grid side of a converter transformer based on multiple means, comprising the following steps:

[0054] Step S1, the partial discharge monitoring sensor 1 detects the signal of the bushing area on the grid side of the converter transformer, the signal of the bushing area on the grid side of the converter transformer includes an ultrasonic signal, a UHF signal and a high-frequency current signal, and the signal acquisition module 3 acquires the signal of the bushing area on the grid side of the converter transformer detected by the partial discharge monitoring sensor 1

[0055] Step S2: The signal analysis and processing module 4 compares and analyzes the signal of the bushing area on the grid side of the converter transformer with the spectrum of the standard partial discharge signal, determines whether the signal of the bushing area on the grid side of the converter transformer is an abnormal signal, and determines whether the abnormal signal is inside or outside the bushing area.

[0056] Step S3: After the signal analysis and processing module 4 determines that an abnormal signal is detected, disconnect the connection line between the signal acquisition module 3 and the partial discharge monitoring sensor 1, connect the charged detection device 2 to the partial discharge monitoring sensor 1, and collect the signal detected by the partial discharge monitoring sensor 1, check whether there is an interference signal in the detected signal, analyze and diagnose the discharge signal characteristics in the detected signal, and locate the discharge signal source.

[0057] The contents not described in detail in this specification belong to the prior art known to those skilled in the art. It should be understood by those skilled in the art that embodiments of the present invention may be provided as methods, systems, or computer program products. Therefore, the present invention may adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present invention may adopt the form of a computer program product implemented in one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program codes.

[0058] 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.

[0059] 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.

[0060] 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 1 A process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0061] 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 its protection scope. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the field should understand that after reading the present invention, those skilled in the art can still make various changes, modifications or equivalent substitutions to the specific implementation methods of the invention, but these changes, modifications or equivalent substitutions are all within the protection scope of the pending claims of the invention.

Claims

1. A partial discharge detection system for bushing area on the grid side of a converter transformer based on multiple means, characterized in that: It comprises a partial discharge monitoring sensor (1), a live detection device (2), a signal acquisition module (3), and a signal analysis and processing module (4); the partial discharge monitoring sensor (1) comprises A ultrasonic sensors (12), B ultra-high frequency sensors (13), and C high-frequency current sensors (14); The partial discharge monitoring sensor (1) is used to detect signals from the bushing area on the grid side of the converter transformer, wherein the signals from the bushing area on the grid side of the converter transformer include ultrasonic signals, ultra-high frequency signals and high-frequency current signals; The signal acquisition module (3) is used to acquire the signal of the bushing area on the converter transformer grid side detected by the partial discharge monitoring sensor (1); The signal analysis and processing module (4) is used to compare and analyze the signal of the bushing area on the converter transformer grid side with the spectrum of the standard partial discharge signal, determine whether the signal of the bushing area on the converter transformer grid side is an abnormal signal, and judge whether the abnormal signal is located inside or outside the bushing area. After the signal analysis and processing module (4) determines that the abnormal signal is detected, disconnect the connection line between the signal acquisition module (3) and the partial discharge monitoring sensor (1), connect the live detection device (2) to the partial discharge monitoring sensor (1), collect the signal detected by the partial discharge monitoring sensor (1), check whether there is an interference signal in the detected signal, analyze and diagnose the discharge signal characteristics in the detected signal, and locate the position of the discharge signal source; The signal analysis and processing module (4) is used to display the monitored signal spectrum, and compare the monitored signal of the bushing area on the grid side of the converter transformer with the standard partial discharge signal spectrum to determine whether the signal of the bushing area on the grid side of the converter transformer is an abnormal signal. The specific method is: Step S21, comparing the waveform characteristics and time difference relationship of the A ultrasonic sensors, determining whether the signal in the bushing area on the grid side of the converter transformer contains an abnormal signal, and determining whether the abnormal signal is a mechanical vibration signal; Step S22, comparing the signals of the two detection channel UHF sensors and the one noise channel UHF sensor, and comparing them with the standard discharge signal spectrum, to determine whether the abnormal signal comes from inside or outside the bushing area on the converter transformer grid side; Step S23, comparing the signals of a detection channel high-frequency current sensor and a noise channel high-frequency current sensor, and comparing them with the standard discharge signal spectrum, to determine whether the abnormal signal comes from inside or outside the bushing area on the converter transformer grid side; The specific method of step S22 is: The abnormal signals detected by the UHF method and the HF method include partial discharge signals and external interference signals; The conditions for determining that the abnormal signal originates from the inner area of ​​the bushing on the converter transformer grid side are: the signal spectrum characteristics of the UHF sensors of the two detection channels conform to the standard discharge signal spectrum, and the signal spectrum of the UHF sensor of the one noise channel does not conform to the standard discharge signal spectrum; or the signal spectra of the UHF sensors of the two detection channels and the UHF sensor of the one noise channel conform to the standard spectrum and the signal amplitudes of the UHF sensors of the two detection channels are greater than the signal amplitude of the UHF sensor of the one noise channel; The conditions for determining that the abnormal signal originates from outside the bushing area on the converter transformer grid side are: the signal spectra of the two detection channel ultra-high frequency sensors do not conform to the standard discharge signal spectrum, or the signal spectra of the two detection channel ultra-high frequency sensors and the one noise channel ultra-high frequency sensor both conform to the standard discharge signal spectrum and the signal amplitudes of the two detection channel ultra-high frequency sensors are smaller than the signal amplitude of the one noise channel ultra-high frequency sensor.

2. The multiple-means based converter transformer grid-side bushing regional partial discharge detection system according to claim 1 is characterized in that: The A ultrasonic sensors (12) are used to monitor the ultrasonic signal and are installed on the surface of the casing of the converter transformer network side bushing elevation seat. The A ultrasonic sensors (12) are grouped into three ultrasonic sensors, and each group of ultrasonic sensors is installed on a circular plane with the center of the bottom surface of the elevation seat as the origin. The three sensors on each circular plane are distributed at equal angles along the circumference, and the center interval of the circular plane where each group of ultrasonic sensors is located is h; The B ultra-high frequency sensors (13) include two detection channel ultra-high frequency sensors and one noise channel ultra-high frequency sensor, wherein the detection channel ultra-high frequency sensors are used to monitor the local discharge signal inside the bushing area on the converter transformer grid side, and the noise channel ultra-high frequency sensor is used to monitor the noise interference signal in the surrounding environment of the bushing on the converter transformer grid side; The C high-frequency current sensors (14) include a detection channel high-frequency current sensor and a noise channel high-frequency current sensor, wherein the detection channel high-frequency current sensor is used to monitor the local discharge signal inside the bushing area on the grid side of the converter transformer, and the noise channel high-frequency current sensor is used to monitor the interference signal in the surrounding environment of the bushing on the grid side of the converter transformer.

3. The multiple-means based converter transformer grid-side bushing regional partial discharge detection system according to claim 2 is characterized in that: The B ultra-high frequency sensors (13) are installed at the connection gap of the bushing elevation seat on the converter transformer network side, wherein the front faces of the two detection channel ultra-high frequency sensors face the inside of the gap, and the connection line of the two detection channel ultra-high frequency sensors is parallel to the axis of the bushing on the converter transformer network side; the front face of the one noise channel ultra-high frequency sensor faces the air outside the elevation seat; after the ultra-high frequency sensors are installed, the coordinate values ​​of the B ultra-high frequency sensors (13) are measured; The one detection channel high-frequency current sensor is installed on the equipotential connecting line of the lifting seat, and the one noise channel high-frequency current sensor is directly tied to the lifting seat.

4. The multiple-means based converter transformer grid-side bushing area partial discharge detection system according to claim 1 is characterized in that: The signal acquisition module (3) is installed near the converter transformer body and is used to collect the signals detected by the partial discharge monitoring sensor (1), and collect and send them to the signal analysis and processing module (4). The signal line interface in the signal acquisition module (3) directly connected to the partial discharge monitoring sensor (1) adopts a BNC interface or an N-type interface for use by the live detection device (2).

5. The multiple-means based converter transformer grid-side bushing regional partial discharge detection system according to claim 1 is characterized in that: The specific method of step S21 is: When the signal waveform has the following characteristics, the abnormal signal is judged to be a partial discharge signal: (1) The signal waveform is an exponentially decaying oscillating waveform, which conforms to the periodic characteristics and phase characteristics of the power frequency voltage, and the waveform is a periodic signal; (2) The amplitudes of the signal waveforms monitored by the A ultrasonic sensor channels are not equal to each other, and the starting edge times of the signal waveforms are different; When the signal waveform has the following characteristics, the abnormal signal is judged to be a mechanical vibration signal: (1) The envelope of the signal waveform is a continuous spindle shape, which does not conform to the phase characteristics of the power frequency voltage; (2) The starting edge times of the signal waveforms monitored by the A ultrasonic sensor channels are all the same.

6. The multiple-means based converter transformer grid-side bushing area partial discharge detection system according to claim 1, characterized in that: The specific method of step S23 is: The conditions for determining that the abnormal signal originates from the inner region of the bushing on the transformer grid side are: the signal spectrum characteristics of the high-frequency current sensor of the one detection channel conform to the standard discharge signal spectrum, and the signal spectrum of the high-frequency current sensor of the one noise channel does not conform to the standard discharge signal spectrum; or the signal spectra of the high-frequency current sensor of the one detection channel and the high-frequency current sensor of the one noise channel both conform to the standard spectrum and the signal amplitude of the high-frequency current sensor of the one detection channel is greater than the signal amplitude of the high-frequency current sensor of the one noise channel; The conditions for determining that the abnormal signal originates from outside the bushing area on the converter transformer grid side are: the signal spectrum of the high-frequency current sensor of the one detection channel does not conform to the standard discharge signal spectrum, or the signal spectra of the high-frequency current sensor of the one detection channel and the high-frequency current sensor of the one noise channel both conform to the standard discharge signal spectrum and the signal amplitude of the high-frequency current sensor of the one detection channel is less than the signal amplitude of the high-frequency current sensor of the one noise channel.

7. The multiple-means based converter transformer grid-side bushing regional partial discharge detection system according to claim 1 is characterized in that: The specific method of the live detection device (2) to detect interference signals is: S31, at the signal acquisition module of the on-line monitoring system for partial discharge in the bushing area on the converter transformer grid side, the live detection device (2) is connected to the partial discharge monitoring sensor (1), and the ultra-high frequency, ultrasonic and high frequency signals detected by the partial discharge monitoring sensor (1) are collected for comparative analysis; S32, if it is determined in step S23 that the abnormal signal originates from outside the bushing area on the grid side of the converter transformer, the ultraviolet imager in the live detection device (2) may be used to detect the bushing elevation seat area on the grid side by adopting the ultraviolet imaging detection method to determine the location of the interference signal source and eliminate it; S33: If it is determined in step S23 that the abnormal signal is located inside the bushing area on the converter transformer grid side, the position of the abnormal signal is determined by a signal source positioning method.

8. The multiple-means based converter transformer grid-side bushing area partial discharge detection system according to claim 7, characterized in that: The signal source positioning method includes the acoustic-acoustic positioning method, the acoustic-electric positioning method and the ultra-high frequency time difference positioning method; When at least four ultrasonic sensors (12) receive a discharge signal simultaneously, an acoustic-acoustic positioning method is used; when at least three ultrasonic sensors (12) and one detection channel ultra-high frequency sensor or one detection channel high frequency current sensor receive a discharge signal simultaneously, an acoustic-electric positioning method is used; and when two detection channel ultra-high frequency sensors receive a discharge signal simultaneously, an ultra-high frequency time difference positioning method is used.

9. A method for detecting partial discharge in the bushing area on the grid side of a converter transformer based on multiple means using the system of claim 1, characterized in that: It includes the following steps: Step S1, the partial discharge monitoring sensor (1) detects a signal from the bushing area on the grid side of the converter transformer, wherein the signal from the bushing area on the grid side of the converter transformer comprises an ultrasonic signal, an ultra-high frequency signal and a high-frequency current signal, and the signal acquisition module (3) acquires the signal from the bushing area on the grid side of the converter transformer detected by the partial discharge monitoring sensor (1); Step S2, the signal analysis and processing module (4) compares and analyzes the signal of the bushing area on the grid side of the converter transformer and the spectrum of the standard partial discharge signal, determines whether the signal of the bushing area on the grid side of the converter transformer is an abnormal signal, and determines whether the abnormal signal is located inside or outside the bushing area; Step S3: After the signal analysis and processing module (4) determines that an abnormal signal is detected, disconnect the connection line between the signal acquisition module (3) and the partial discharge monitoring sensor (1), connect the charged detection device (2) to the partial discharge monitoring sensor (1), and collect the signal detected by the partial discharge monitoring sensor (1), check whether there is an interference signal in the detected signal, analyze and diagnose the discharge signal characteristics in the detected signal, and locate the position of the discharge signal source.

Images