Non-intrusive multi-mode partial discharge online detection and positioning system

Abstract

The invention discloses a non-intrusive multi-mode partial discharge online detection and positioning system, and belongs to the field of detection. A detector integrated with a plurality of signal acquisition sensors is arranged; the detector adopts a non-intrusive magnetic pasting type shell design structure; the detector realizes non-intrusive multi-mode signal synchronous acquisition based on a hyperboloid positioning algorithm of three times of measurement intersection, and a radiation coil of signal generation can be obtained by using the synchronism of signal acquisition; through three times of measurement, after three groups of hyperboloid equations are constructed, spherical intersection points of the three groups of hyperboloid equations are solved, and the accurate position where partial discharge occurs can be obtained. Through a non-intrusive mounting mode of a magnetic type shell, a hyperboloid equation is constructed by utilizing a signal arrival time difference, three-point positioning is realized by virtue of a multi-modal method, centimeter-level accurate positioning of a partial discharge source is realized, and the precision and reliability of partial discharge detection are greatly improved. The method can be widely applied to the field of operation and fault monitoring of electric power supply equipment.

Description

Technical Field

[0001] This invention belongs to the field of electrical equipment insulation defect detection, and particularly relates to a non-invasive multimodal partial discharge online detection and location system for switchgear. Background Technology

[0002] Partial discharge (PD) is a phenomenon where a discharge occurs only in a localized area of ​​an insulator and does not penetrate between conductors to which a voltage is applied. It can occur near the conductor or elsewhere.

[0003] Partial discharge refers to the incomplete discharge phenomenon that occurs in a local area of ​​the internal insulation system of electrical equipment under the action of a strong electric field.

[0004] Partial discharge is a significant factor leading to insulation failures in switchgear, and timely and accurate monitoring of partial discharge is crucial for ensuring the safe operation of equipment.

[0005] In switchgear, partial discharge is often caused by the following issues:

[0006] 1. The cable head is not properly sealed and has become damp;

[0007] 2. Aging and cracking of the solid insulation layer;

[0008] 3. Inadequate installation process or poor contact.

[0009] Although partial discharge current is weak, its prolonged presence can rapidly deteriorate insulation and even cause explosions. Therefore, early detection and accurate assessment are the first step in ensuring the safe operation of the power grid. Statistics show that partial discharge is a major cause of insulation breakdown in high-voltage electrical equipment and a significant indicator of insulation degradation.

[0010] Every partial discharge has some effect on the insulating medium. Minor partial discharges have a smaller impact on the insulation of electrical equipment, and the decrease in insulation strength is slower; however, strong partial discharges cause the insulation strength to decrease rapidly. This is an important factor causing damage to the insulation of high-voltage electrical equipment.

[0011] Partial discharge in insulation affects its lifespan. Each discharge, with its impact of high-energy electrons or accelerated electrons, especially long-term partial discharge, causes various physical and chemical effects. For example, when charged particles collide with the outer wall of a bubble, they may break the chemical bonds of the insulation, causing it to decompose, damaging its molecular structure, and leading to insulation degradation and accelerated damage.

[0012] Partial discharge (PD) in switchgear can lead to the gradual deterioration of insulation materials, eventually resulting in insulation failure and electrical faults. Therefore, monitoring and detecting PD in switchgear is crucial.

[0013] How to prevent and remove partial discharge from electrical equipment to ensure its normal and safe operation has become the most important concern for electrical equipment maintenance personnel.

[0014] Existing partial discharge detection methods, including TEV (Transient Earth Voltage), UHF (Ultra-High Frequency), and ultrasonic technologies, can all be used for independent monitoring.

[0015] Each signal type relies on specific rules to determine whether partial discharge exists. For example, TEV signals are analyzed through voltage waveform changes, while ultrasonic signals determine faults based on the characteristics of sound wave propagation.

[0016] However, these existing technologies typically analyze various signals independently, failing to provide comprehensive analysis of multimodal signals or coordinate localization. Therefore, the monitoring accuracy of partial discharge signals is limited by the single signal type, unable to address noise interference, and unable to overcome the impact of different detection methods on the effectiveness of various partial discharge defect categories.

[0017] A utility model patent, authorized on June 14, 2024, with authorization announcement number CN 221148832 U, discloses a "partial discharge detection system for switchgear," comprising: at least one signal detection device, each of which includes a TEV detection unit for detecting TEV signals, an ultrasonic detection unit for detecting ultrasonic signals, and a signal processing and communication unit for converting the TEV and ultrasonic signals; a relay communication unit for receiving and integrating the converted TEV and ultrasonic signals; a host computer for displaying and providing early warning of the TEV and ultrasonic signals; and magnetic devices corresponding to each signal detection device for fixing the signal detection device to the switchgear. Implementing this utility model allows workers to promptly detect switchgear with insulation defects and perform timely maintenance. It also has the advantage of convenient installation, which is beneficial for improving the stability and safety of nuclear power plant power systems. However, because it lacks a positioning function, it cannot provide a specific indication of which part of the switch cabinet the partial discharge is occurring in. Operators still need to open the switch cabinet for further testing and confirmation. It cannot quickly and timely indicate the specific location of the partial discharge (referred to as "partial discharge source") to the staff.

[0018] A utility model patent, authorized on November 22, 2024, with authorization announcement number CN 222050364 U, discloses "a multi-functional partial discharge detector," comprising a main body. A connecting cable is connected to the detection interface of the main body, and the other end of the connecting cable is connected to a magnetic probe for detection. A buffer mechanism is provided on the outside of the magnetic probe to buffer the magnetic force between the magnetic probe and the detection cabinet. The buffer mechanism includes a sleeve, which is fixedly installed on the outside of the magnetic probe. This technical solution, by setting a buffer mechanism on the outside of the magnetic probe, allows the magnetic probe to be brought close to the detection cabinet during detection. During this process, the magnetic force generated by the magnetic probe partially cancels out the restoring force of the shock-absorbing spring, thereby reducing the inertia generated by the magnetic force and achieving a buffering effect. Simultaneously, pressing the pressure plate increases the distance between the magnetic probe and the detection cabinet, reducing the attraction force between them and facilitating the removal of the magnetic probe along with the buffer mechanism. Similarly, because this technical solution requires moving the magnetic probe to determine the location of partial discharge, it does not have an automatic positioning function and cannot provide a specific indication of which part of the switch cabinet the partial discharge is occurring in. Operators still need to open the switch cabinet for further inspection and confirmation. It cannot quickly and timely indicate the specific location of the partial discharge to the staff, and cannot meet the usage requirement of "determining the specific location of the partial discharge in the cabinet without interfering with the operation of the equipment". Summary of the Invention

[0019] The purpose of this invention is to provide a non-invasive multimodal partial discharge (PD) online detection and localization system. It is non-invasively installed using a magnetically attached housing and integrates TEV (Transient Ground Voltage), UHF (Ultra-High Frequency), pulse current, and dual-mode ultrasonic sensors. It utilizes the time difference of arrival (TDOA) to construct a hyperboloid equation and combines it with a three-measurement intersection localization algorithm to achieve centimeter-level precise localization of the PD source.

[0020] The technical solution of this invention is: to provide a non-invasive multimodal partial discharge online detection and positioning system, including real-time online monitoring of equipment status without interfering with equipment operation; its characteristic is:

[0021] Set up a detector that integrates multiple signal acquisition sensors;

[0022] The detector adopts a non-invasive magnetic shell design.

[0023] The detector is based on a hyperboloid positioning algorithm that intersects three measurements to achieve non-invasive multimodal signal synchronous acquisition. By utilizing the synchronicity of signal acquisition, the radiation zone of the signal can be obtained. After constructing three sets of hyperboloid equations through three measurements, the spherical intersection of the three sets of hyperboloid equations can be solved to obtain the precise location of the partial discharge.

[0024] Specifically, the various signal acquisition sensors include at least a pulse current sensor, an air ultrasonic sensor, a TEV sensor, a UHF sensor, and a surface ultrasonic sensor.

[0025] Furthermore, the pulse current sensor interface is three-phase.

[0026] Specifically, the detector has the function of detecting pulse current signals, air ultrasonic signals, TEV signals, UHF signals and surface ultrasonic signals.

[0027] Specifically, the detector transmits the processed partial discharge data to the remote monitoring platform in real time via wireless communication technology; the remote monitoring platform uses big data analysis and cloud computing technology to store and process the data, and provides fault warning, health status assessment and historical data backtracking.

[0028] Specifically, the detector uses the time difference between a pulsed current signal and an ultrasonic signal, or between a TEV signal and an ultrasonic signal, and by utilizing the synchronicity of signal acquisition, the radiation zone of the signal can be obtained.

[0029] Furthermore, the detector constructs three sets of hyperboloid equations by simultaneously measuring pulse current signals and ultrasonic signals, or TEV signals and ultrasonic signals, three times, and then solves for their spherical intersection points.

[0030] Specifically, the non-invasive multimodal partial discharge (PD) online detection and location system acquires pulse current signals through a phase-hole sensor to monitor the presence and intensity of PD; captures high-frequency electromagnetic waves caused by PD inside the equipment using a dedicated UHF sensor to detect insulation defects; acquires TEV signals by detecting current fluctuations formed when electromagnetic waves released by PD inside the equipment reach the switch cabinet surface; detects mechanical vibrations and contact surface faults caused by PD using a contact surface ultrasonic sensor to provide information on physical defects inside the equipment; and uses an air ultrasonic sensor to capture ultrasonic signals caused by PD outside the equipment to further confirm the presence and severity of PD.

[0031] Furthermore, the ultrasonic sensor for the contact surface is a piezoelectric sensor.

[0032] The aforementioned non-invasive multimodal partial discharge online detection and positioning system integrates multiple signal acquisition technologies and adopts a non-invasive magnetic shell design. A single detector simultaneously measures pulse current signals, UHF signals, TEV signals, and ultrasonic signals. By using the time difference between the pulse current signal and the ultrasonic signal, or between the TEV signal and the ultrasonic signal, three sets of hyperboloid equations are constructed through three measurements to achieve three-point positioning, thereby significantly improving the accuracy and reliability of partial discharge detection.

[0033] Compared with the prior art, the advantages of the present invention are:

[0034] 1. The technical solution of the present invention integrates multiple signal acquisition technologies (pulse current, UHF, ultrasound, etc.) and adopts a non-invasive magnetic shell design, which enables real-time online monitoring of equipment status without interfering with equipment operation, and achieves three-point positioning through a multi-modal method, thereby significantly improving the accuracy and reliability of partial discharge detection.

[0035] 2. The technical solution of the present invention integrates TEV (Transient Ground Voltage), UHF (Ultra-High Frequency), pulse current and dual-mode ultrasonic sensors through non-intrusive installation with a magnetic shell, utilizes the signal arrival time difference (TDOA) to construct a hyperboloid equation, and combines a three-measurement intersection positioning algorithm to achieve centimeter-level precise positioning of the partial discharge source;

[0036] 3. The technical solution of the present invention involves a single detector simultaneously measuring pulse current, UHF, TEV, and ultrasound. By using the time difference between the pulse current signal and the ultrasound signal, or between the TEV signal and the ultrasound signal, and utilizing the synchronization of the acquisition, the radiation zone of the signal can be obtained. After constructing three sets of hyperboloid equations through three measurements, the precise location of partial discharge can be obtained by solving their spherical intersection points. Attached Figure Description

[0037] Figure 1 is a schematic diagram of the hardware structure of the present invention;

[0038] Figure 2 is a schematic diagram of the principle of 3-point partial discharge localization using the pulse current / TEV-ultrasound method of the present invention.

[0039] Figure 3 This is a schematic diagram of the topological structure of the measurement system of the present invention.

[0040] In the figure, 1 is the pulse current sensor interface (three-phase), 2 is the air ultrasonic sensor, 3 is the TEV sensor, 4 is the UHF sensor, 5 is the surface ultrasonic sensor, and 6 is the detector housing. Detailed Implementation

[0041] The invention will now be further described with reference to the accompanying drawings.

[0042] Existing partial discharge detection technologies face two major problems:

[0043] 1) Spatiotemporal asynchrony: Due to differences in physical characteristics, sensors such as TEV, ultrasonic, and UHF are difficult to measure simultaneously at the same point (time error > 100ns).

[0044] 2) Ambiguous positioning: Single-point detection method is limited by equipment structure and cannot distinguish signals superimposed by multiple discharge sources (such as the coexistence of suspended discharge and particle discharge in GIS).

[0045] This invention integrates multiple signal acquisition technologies (pulse current, UHF, ultrasound, etc.) and adopts a non-invasive magnetic shell design, enabling real-time online monitoring of equipment status without interfering with equipment operation. Furthermore, it achieves three-point positioning through a multimodal method, thereby significantly improving the accuracy and reliability of partial discharge detection.

[0046] In the technical solution of this invention, a single detector simultaneously measures pulse current, UHF, TEV, and ultrasound. For example... Figure 1 As shown.

[0047] I. Hardware configuration of the technical solution of this invention:

[0048] Specifically, such as Figure 1 As shown in the figure, in this technical solution, a pulse current sensor interface (three-phase) 1, an air ultrasonic sensor 2, a TEV sensor 3, a UHF sensor 4, and a surface ultrasonic sensor 5 are synchronously arranged on the detector housing 6.

[0049] In this technical solution, the detector is synchronously connected to a pulse current sensor, an air ultrasonic sensor, a TEV sensor, a UHF sensor, and a surface ultrasonic sensor, and simultaneously has the function of detecting pulse current signals, air ultrasonic signals, TEV signals, UHF signals, and surface ultrasonic signals.

[0050] Data transmission and remote monitoring of the detector:

[0051] The processed partial discharge data is transmitted to the remote monitoring platform in real time using wireless communication technology (such as LoRa modules).

[0052] The monitoring platform uses big data analytics and cloud computing technologies to store and process data, and provides fault warnings, health status assessments, and historical data backtracking.

[0053] In this technical solution, the types, detection functions, and characteristics of various measurement signals are as follows:

[0054] Pulse current signal: Pulse current signals are acquired through the phase aperture to monitor the presence and intensity of partial discharge sources. Pulse current signals can efficiently detect electrical faults and have high sensitivity.

[0055] UHF (Ultra-High Frequency 300MHz-3GHz) signals: High-frequency radio waves caused by partial discharge inside the equipment are captured by a dedicated UHF sensor. UHF signals can penetrate insulating materials and are suitable for detecting insulation defects.

[0056] TEV (1M-100MHz) signal: Electromagnetic waves released by the partial discharge inside the equipment reach the surface of the switch cabinet, forming current fluctuations.

[0057] Ultrasonic signals: The contact surface ultrasonic sensor (such as a piezoelectric sensor) detects mechanical vibrations and contact surface faults caused by partial discharge, providing information on physical defects inside the equipment.

[0058] Airborne ultrasonic signal: An airborne ultrasonic sensor is used to capture ultrasonic signals caused by partial discharge outside the device to further confirm the presence and severity of the partial discharge.

[0059] Since the aforementioned sensors and their working principles are existing technologies, and various sensors are available in numerous specifications and types from different manufacturers, their specific working principles and implementation circuits will not be detailed again. Those skilled in the art can easily implement the corresponding detection functions by referring to the product samples and reference circuits provided by the respective sensor manufacturers.

[0060] II. Measurement principle of the technical solution of the present invention:

[0061] In Figure 2, the technical solution of the present invention uses a multi-sensor multi-modal localization method to determine the "partial discharge source", realizes non-invasive multi-modal signal synchronous acquisition, and solves the difficulty of simultaneous detection at the same point by multiple sensors.

[0062] Specifically, the technical solution of this invention, based on the hyperboloid positioning algorithm of three intersecting measurements, breaks through the physical limitations of traditional detection methods through multi-sensor spatiotemporal joint calibration, thereby realizing non-invasive multimodal signal synchronous acquisition and solving the difficulty of simultaneous detection at the same point by multiple sensors.

[0063] Hyperbolic Positioning is a spatial positioning technique based on the time difference of arrival (TDOA). It measures the propagation time difference from the target signal source to multiple known receivers, constructs a system of hyperbolic equations with the receivers as the focus, and solves for the spatial coordinates of the target.

[0064] In practical implementation, the technical solution of the present invention is based on the hyperboloid positioning algorithm to achieve spatiotemporal synchronization of multiple sensors. It improves positioning accuracy through signal spatiotemporal correlation and three-dimensional reconstruction, and is especially suitable for complex power equipment scenarios.

[0065] Hyperbolic positioning is a spatial positioning technique based on the time difference of arrival (TDOA). It measures the propagation time difference from a target signal source to multiple known receiver locations, constructs a system of hyperbolic equations with the receivers as foci, and then solves for the target's spatial coordinates.

[0066] By leveraging the advantages of hyperboloid positioning algorithms and constructing a system of time-difference equations to solve for the spatial coordinates of the signal source, the following advantages are achieved:

[0067] 1) Non-invasive: Only requires an external sensor array;

[0068] 2) Anti-interference capability: Time difference measurement can suppress common-mode noise;

[0069] 3) Multi-source analysis: Supports joint calculation of 4+ sensors.

[0070] Specifically, by using the time difference between pulsed current signals and ultrasonic signals, or between TEV signals and ultrasonic signals, and by utilizing the synchronicity of signal acquisition, the radiation zone of the signal can be obtained.

[0071] By conducting three measurements and constructing three sets of hyperboloid equations, the precise location of the partial discharge can be obtained by solving for its spherical intersection point.

[0072] D i / V 超声 - D i / V c = δt i (i=1,2,3);

[0073] Where, δt i It is known that this is due to synchronous data acquisition;

[0074] The signal obtained by the pulse current method and TEV is approximately V c In general calculations, because V c Since the cabinet dimensions are much larger than those of the switchgear, the second item can be ignored, and it becomes:

[0075] D i = δt i × V 超声 (i=1,2,3);

[0076] Finally, according to the system of equations:

[0077] (XXi ) 2 + (YY i ) 2 + (ZZ i ) 2 = D i (i=1,2,3);

[0078] The location of the partial discharge occurrence point, i.e., the intersection of the three radiation rings, can be obtained. (Where the coordinates are (X...) i Y i Z i (The coordinates of the detector position are shown in the image).

[0079] III. System Architecture Design of the Technical Solution of the Invention:

[0080] 3.1 Hardware Subsystem:

[0081] 3.1.1 Multimodal sensor array:

[0082] Sensor type, parameter requirements, and layout principles: TEV bandwidth 3-100MHz, sensitivity 5mV; equally spaced arrangement on metal surface; UHF 300MHz-1.5GHz, dynamic range 80dB; circumferential arrangement at insulating flange; ultrasonic 40kHz center frequency, SNR>60dB; hexahedral vertices preferred.

[0083] 3.1.2 Synchronous Acquisition Module:

[0084] Atomic clock synchronization: GPS-disciplined rubidium clock (accuracy 1e-12);

[0085] Triggering architecture: Master-slave FPGA trigger chain (jitter <1ns).

[0086] 3.2 Software Processing Flow:

[0087] graph TD

[0088] A [Signal Preprocessing] → B [Time Difference Extraction];

[0089] B→C [Construction of hyperboloid equation];

[0090] C → D [Levenberg-Marquardt optimization];

[0091] D → E [3D coordinate output]

[0092] IV. Implementation method of core algorithm:

[0093] 4.1 Time Difference Measurement Model:

[0094] Let sensor S i Coordinates are (xi ,y i ,z i The distance difference between the power supply P(x,y,z) and each sensor is: Δd ij = c·Δt ij = |PS i | - |PS j | ;where c is the speed of electromagnetic wave propagation (UHF is based on the speed of light, TEV on 0.9c)

[0095] 4.2 Construction of the hyperboloid equation system:

[0096] Using S1 as the reference sensor, establish the following system of equations:

[0097] √[(x-x2)²+(y-y2)²+(z-z2)²] - [(x-x1)²+(y-y1)²+(z-z1)²] = c·Δt 12 , ...,

[0098] √[(xx n )²+(yy n )²+(zz n )²] - [(x-x1)²+(y-y1)²+(z-z1)²] = c·Δt 1n .

[0099] 4.3 Nonlinear Optimization Solution:

[0100] The initial estimate is iteratively corrected using the LM algorithm:

[0101] , where J is the Jacobian matrix and λ is the damping factor.

[0102] Example:

[0103] Example 1:

[0104] GIS equipment with multiple power supply positioning:

[0105] Test conditions:

[0106] Equipment: ZF12-126 GIS, containing artificially created floating discharge and particle discharge defects.

[0107] Sensor layout: 8UHF + 6TEV + 4 ultrasonic sensors, synchronization accuracy 0.5ns;

[0108] Result comparison:

[0109] Method positioning error (mm) and multi-source recognition rate: Traditional TEV method >3000%, this solution 18.792.3%.

[0110] Key data:

[0111] Standard deviation of time difference measurement: 0.8 ns;

[0112] Calculation time: <300ms / time.

[0113] Example 2:

[0114] Transformer winding discharge monitoring:

[0115] Special challenges: complex electromagnetic environment (power frequency interference > 80 dBμV); distortion of acoustic and electrical signal propagation paths;

[0116] Innovative measures:

[0117] Adaptive band-stop filtering: suppresses 100Hz / 200Hz harmonics;

[0118] Establish a winding propagation correction model: V effective = 0.67c·exp (-0.032f) (f is the frequency in MHz);

[0119] On-site verification:

[0120] In the testing of the 220kV main transformer, an inter-turn discharge 1.2m from the winding end was successfully identified, with an amplitude quantization error of <5%.

[0121] Based on field measurements, the comparison results between the system scheme of this invention and the existing TEV independent detection method or TEV + UHF asynchronous detection method are as follows:

[0122] Detection method Positioning error False alarm rate Average processing time TEV Independent Testing >45 cm 12.5% 0.8 seconds TEV + UHF asynchronous 30~40 cm 7.8% 1.2 seconds The system solution of the present invention < 8 cm 1.5% 0.32 seconds

[0123] Furthermore, the maintenance efficiency has been greatly improved after adopting this technical solution: the time for a single inspection has been reduced from 4 hours to 0.5 hours; the accuracy of fault early warning has increased from 72% to 94% (actual data from a provincial power grid).

[0124] like Figure 3 As shown, the technical solution of this invention employs a pulsed current method combined with direct detection technology. The pulsed current method achieves monitoring by detecting the steep rising edge current pulse signal generated by partial discharge (PD). Its core lies in utilizing the phase-recording aperture of the live indicator in the high-voltage switchgear as a signal acquisition point. The phase-recording aperture is short-circuited to the low-voltage arm of the capacitance sensor inside the live indicator. When partial discharge occurs inside the switchgear, the discharge pulse is coupled to the phase-recording aperture through the insulator capacitance sensor, forming a detectable pulsed current signal. That is, it equivalently achieves the impedance measurement function in the traditional pulsed current method. It captures the high-frequency current pulse signal (150kHz~30MHz) generated by partial discharge.

[0125] V. Data Transmission and Remote Monitoring:

[0126] The processed partial discharge data is transmitted to the remote monitoring platform in real time using wireless communication technology (such as LoRa modules).

[0127] The monitoring platform uses big data analytics and cloud computing technologies to store and process data, and provides fault warnings, health status assessments, and historical data backtracking.

[0128] In summary, the technical solution of this invention integrates TEV (Transient Ground Voltage), UHF (Ultra-High Frequency), pulse current, and dual-mode ultrasonic sensors through a non-intrusive magnetic housing installation mode. It utilizes the time difference of arrival (TDOA) to construct a hyperboloid equation and combines it with a three-measurement intersection positioning algorithm to achieve three-point positioning through a multimodal method, thereby realizing centimeter-level precise positioning of the partial discharge source and significantly improving the accuracy and reliability of partial discharge detection.

[0129] This invention can be widely used in the field of power supply equipment operation and fault monitoring.

Claims

1. A non-invasive multimodal partial discharge online detection and positioning system, comprising real-time online monitoring of equipment status without interfering with equipment operation; characterized in that: Set up a detector that integrates multiple signal acquisition sensors; The detector adopts a non-invasive magnetic shell design. The detector is based on a hyperboloid positioning algorithm that intersects three measurements to achieve non-invasive multimodal signal synchronous acquisition. By utilizing the synchronicity of signal acquisition, the radiation zone of the signal can be obtained. After constructing three sets of hyperboloid equations through three measurements, the spherical intersection of the three sets of hyperboloid equations can be solved to obtain the precise location of the partial discharge.

2. The non-invasive multimodal localization online detection and positioning system according to claim 1, characterized in that: The various signal acquisition sensors mentioned include at least a pulse current sensor, an air ultrasonic sensor, a TEV sensor, a UHF sensor, and a surface ultrasonic sensor.

3. The non-invasive multimodal localization online detection and positioning system according to claim 2, characterized in that: The pulse current sensor interface is three-phase.

4. The non-invasive multimodal localization online detection and positioning system according to claim 1, characterized in that: The detector has the function of detecting pulse current signals, air ultrasonic signals, TEV signals, UHF signals and surface ultrasonic signals.

5. The non-invasive multimodal localization online detection and positioning system according to claim 1, characterized in that: The detector transmits the processed partial discharge data to a remote monitoring platform in real time via wireless communication technology. The remote monitoring platform uses big data analysis and cloud computing technology to store and process the data, and provides fault warning, health status assessment and historical data backtracking.

6. The non-invasive multimodal localization online detection and positioning system according to claim 1, characterized in that: The detector uses the time difference between a pulsed current signal and an ultrasonic signal, or between a TEV signal and an ultrasonic signal, and by utilizing the synchronicity of signal acquisition, the radiation zone of the signal can be obtained.

7. The non-invasive multimodal localization online detection and positioning system according to claim 6, characterized in that: The detector constructs three sets of hyperboloid equations by simultaneously measuring pulse current signals and ultrasonic signals, or TEV signals and ultrasonic signals, three times, and then solves for their spherical intersection points.

8. The non-invasive multimodal localization online detection and positioning system according to claim 1, characterized in that: The non-invasive multimodal partial discharge online detection and positioning system acquires pulse current signals through a nuclear phase aperture to monitor the presence and intensity of partial discharge sources. High-frequency electromagnetic waves caused by partial discharge inside the equipment are captured by a dedicated UHF sensor and used to detect insulation defects. TEV signals are collected by the current fluctuations generated by the electromagnetic waves released by the partial discharge inside the equipment reaching the surface of the switch cabinet. The contact surface ultrasonic sensor detects mechanical vibrations and contact surface faults caused by partial discharge, providing information on physical defects inside the equipment. An air ultrasonic sensor is used to capture ultrasonic signals caused by partial discharge outside the device to further confirm the presence and severity of the partial discharge.

9. The non-invasive multimodal localization online detection and positioning system according to claim 8, characterized in that: The ultrasonic sensor for the contact surface is a piezoelectric sensor.

10. The non-invasive multimodal localization online detection and positioning system according to claim 1, characterized in that: By integrating multiple signal acquisition technologies and adopting a non-invasive magnetic shell design, a single detector can simultaneously measure pulse current signals, UHF signals, TEV signals, and ultrasonic signals. By using the time difference between the pulse current signal and the ultrasonic signal, or between the TEV signal and the ultrasonic signal, three sets of hyperboloid equations are constructed through three measurements to achieve three-point positioning, thereby significantly improving the accuracy and reliability of partial discharge detection.

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