Flexible sensor array based on transient ground voltage

Abstract

The invention discloses a flexible sensor array based on transient ground voltage. The flexible sensor array comprises a shell which is made of a flexible polymer material and is adaptive to a curved surface structure of a cable terminal surface; the plurality of sensor units are arranged on the surface of the shell at intervals and detect TEV signals on the surface of the cable terminal in a capacitive coupling mode; and one end of the signal cable is electrically connected with the sensor unit on the shell, and the other end of the signal cable is connected with the signal processing module and the wireless communication module at the rear end, so that real-time transmission and remote monitoring of partial discharge signals are realized. The flexible polymer material is adopted to prepare the sensor array, so that the sensor can be tightly attached to the semi-conductive curved surface of the cable terminal, efficient, low-cost, stable and real-time online partial discharge monitoring of the cable terminal is realized, and the safety and reliability of a power system are improved.

Description

Technical Field

[0001] This invention relates to the field of electrical equipment technology, and more particularly to a flexible sensor array based on transient ground voltage. Background Technology

[0002] Cable systems are among the most important and complex infrastructure components of power systems, and their safe operation directly affects the reliability and quality of power supply. In cable systems, cable terminals connect medium- and high-voltage cables to electrical equipment. Due to long-term exposure to environmental, mechanical, and electrical stresses, they are highly susceptible to insulation defects. These defects, under the influence of strong and non-uniform electric fields, can induce partial discharge. If not detected in time, this can lead to insulation degradation, equipment failure, and even large-scale power outages, resulting in high maintenance costs and severe power interruptions. Therefore, there is an urgent need for a low-cost, highly sensitive, easy-to-install, and adaptable online partial discharge monitoring technology for cable terminals to address the shortcomings of existing methods in cable terminal detection. Summary of the Invention

[0003] The purpose of this invention is to overcome the shortcomings of existing partial discharge monitoring methods and provide a flexible sensor array based on transient ground voltage. This array can effectively solve problems related to adaptability, sensitivity, cost, interference, and installation in partial discharge detection of cable terminals, achieving efficient, low-cost, stable, and real-time online partial discharge monitoring of cable terminals, thereby improving the safety and reliability of power systems.

[0004] The technical solution adopted in this invention is:

[0005] A flexible sensor array based on transient ground voltage is used for online monitoring of partial discharge at cable terminals. The flexible sensor array includes:

[0006] The housing is made of a flexible polymer material with a curved structure that adapts to the surface of the cable termination.

[0007] Multiple sensor units are spaced apart on the surface of the housing and detect the TEV signal on the surface of the cable terminal through capacitive coupling.

[0008] The signal cable is electrically connected at one end to the sensor unit on the housing, and at the other end to the signal processing module and wireless communication module at the rear, enabling real-time transmission and remote monitoring of partial discharge signals.

[0009] Furthermore, the curved surface structure is a ring-shaped structure with an opening.

[0010] Furthermore, each sensor unit adopts a dual-capacitor series sensor structure. Each sensor unit includes an output electrode, an intermediate layer, and a ground electrode stacked sequentially within a sealed insulating enclosure. The output electrode, intermediate layer, and ground electrode are arranged from near to far from the surface of the cable terminal. A self-capacitance is formed between the output electrode and the ground electrode. An interactive capacitance is formed between the output electrode and the surface of the cable terminal through an air gap. The output electrode and the ground electrode extend out of the sealed insulating enclosure through lead-out signal lines.

[0011] Furthermore, the sealed insulating enclosure is a plastic film.

[0012] Furthermore, multiple sensor units are arranged in an array to cover different parts of the cable terminal surface, thereby improving detection coverage and sensitivity.

[0013] Furthermore, the four sensor units are evenly distributed on the inner side of the housing close to the cable terminal surface.

[0014] Furthermore, the wireless communication module adopts a 4G or 5G communication module with high-speed data transmission and anti-interference protocol to upload monitoring data to the remote monitoring platform in real time.

[0015] Furthermore, the remote monitoring platform integrates artificial intelligence and / or machine learning algorithms to analyze partial discharge data, predict fault types, and estimate the remaining lifespan of the device under test.

[0016] The present invention, employing the above technical solutions, has the following beneficial effects: 1) Significantly improves the adaptability and sensitivity to the detection of curved cable terminal structures: Traditional TEV sensors, based on rigid structures, are difficult to fit into semi-conductive curved surfaces, resulting in low signal acquisition efficiency. The present invention uses flexible polymer materials and a dual-capacitor structure, allowing the sensor array to fit tightly into the curved surface of the cable terminal, increasing the effective coupling area. Through simulation and experimental verification, the present invention improves sensitivity by more than 30% compared to traditional TEV sensors and can stably capture nanosecond-level partial discharge pulses. 2) Enhances signal stability and accuracy through the dual-capacitor structure and signal processing technology: The dual-capacitor structure (self-capacitance and mutual capacitance in series) designed in the present invention can suppress sensitivity fluctuations caused by small changes in installation position and reduce the risk of frequency band degradation. Combined with wavelet transform filtering algorithms, it effectively separates environmental noise and partial discharge signals. Experiments show that under the same electromagnetic interference environment, the signal-to-noise ratio of the present invention is improved by about 40%, and the false alarm rate is reduced to below 5%. 3) Significantly reduced hardware costs and simplified installation: Compared to UHF / VHF methods requiring high-frequency sampling hardware, this invention uses low-cost flexible electrode materials and standard RC filter circuits, reducing hardware costs by 50%. The sensor array supports modular installation, requiring no special tools, shortening installation time by 40%, and is suitable for large-scale power distribution network deployments. 4) Strong anti-interference capability based on TEV mechanism ensures data reliability: This invention utilizes the propagation characteristics of transient ground voltage on semiconductor surfaces, avoiding direct contact with high-voltage components and naturally shielding common-mode electromagnetic interference. Comparative tests show that under transient interference from 10kV switch operation, the signal distortion of this invention is less than 1 / 3 of that of traditional high-frequency methods, and data reliability is improved by 30%. 5) Integrated wireless communication enables real-time monitoring and intelligent early warning: Through 4G / 5G wireless modules and cloud platform integration, this invention supports millisecond-level data upload and remote diagnostics. Historical data shows that the system can advance fault warning time by 20%, reducing power outages caused by sudden insulation faults and preventing economic losses exceeding one million yuan annually. Attached Figure Description

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

[0018] Figure 1 This is a schematic diagram of the structure of a flexible sensor array based on transient ground voltage according to the present invention;

[0019] Figure 2 A schematic diagram illustrating the propagation principle of transient ground voltage (TEV) signals;

[0020] Figure 3 A schematic diagram of the electromagnetic wave propagation path on the inner and outer surfaces of a cable terminal;

[0021] Figure 4 A schematic diagram of the lumped parameter equivalent circuit for TEV detection;

[0022] Figure 5 A schematic diagram of the electromagnetic wave propagation process of a cable terminal for TEV testing;

[0023] Figure 6 A schematic diagram of a traditional TEV sensor and its corresponding simplified traveling wave model;

[0024] Figure 7 This is a schematic diagram of the TEV sensor of the present invention and the corresponding simplified traveling wave model. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings.

[0026] like Figure 1 As shown, this invention discloses a flexible sensor array based on transient ground voltage for online monitoring of partial discharge at cable terminals. The flexible sensor array includes:

[0027] Housing 1 is made of flexible polymer material with a curved structure that adapts to the surface of the cable terminal;

[0028] Multiple sensor units 2 are spaced apart on the surface of housing 1 and detect the TEV signal on the surface of the cable terminal through capacitive coupling.

[0029] The signal cable 3 is electrically connected at one end to the sensor unit 2 on the housing 1, and at the other end to the signal processing module and wireless communication module at the rear end, so as to realize the real-time transmission and remote monitoring of partial discharge signals.

[0030] Furthermore, the curved surface structure is a ring-shaped structure with an opening.

[0031] Furthermore, each sensor unit 2 adopts a dual-capacitor series sensor structure. Each sensor unit 2 includes an output electrode 21, an intermediate layer 22, and a ground electrode 23 stacked sequentially within a sealed insulating enclosure 24. The output electrode 21, intermediate layer 22, and ground electrode 23 are arranged from near to far from the surface of the cable terminal. A self-capacitance is formed between the output electrode 21 and the ground electrode 23. An interactive capacitance is formed between the output electrode 21 and the surface of the cable terminal through the air gap. The output electrode 21 and the ground electrode 23 extend out of the sealed insulating enclosure 24 through lead-out signal lines.

[0032] Furthermore, further optimization of the sensor's sensitivity and signal-to-noise ratio will make it more effective in these special environments. Optimizing the capacitor structure and increasing the sensor's frequency response range can further improve its ability to capture low-level signals. Simultaneously, employing advanced denoising algorithms during signal processing, such as wavelet transform-based noise removal techniques, can effectively reduce the impact of environmental noise on the signal.

[0033] Furthermore, the sealed insulating enclosure 24 is a plastic film.

[0034] Furthermore, multiple sensor units 2 are arranged in an array to cover different parts of the cable terminal surface, thereby improving detection coverage and sensitivity.

[0035] Specifically, to further improve monitoring coverage and sensitivity, multiple sensor units 2 can be combined into a multi-sensor array, and the sensor arrangement can be optimized. By deploying multiple sensor arrays at different locations on the cable terminal, simultaneous monitoring of different parts of the cable terminal surface can be achieved, enhancing the comprehensiveness of the detection. This optimization scheme can effectively avoid the problem of omissions caused by a single sensor failing to cover certain areas, while improving overall detection sensitivity and reducing signal attenuation caused by changes in sensor distance.

[0036] Furthermore, the four sensor units 2 are evenly distributed on the inner side of the housing 1 close to the surface of the cable terminal.

[0037] Furthermore, the wireless communication module employs a 4G or 5G communication module with high-speed data transmission and anti-interference protocols to upload monitoring data to the remote monitoring platform in real time. Specifically, to further improve the efficiency and real-time performance of the monitoring system, the wireless communication module can be optimized to enhance data transmission speed and anti-interference capabilities. By adopting more advanced wireless communication technologies, data transmission from the sensor array can be made more efficient and stable. The optimized communication module can support higher data transmission rates, ensuring that real-time data can be uploaded to the remote monitoring platform without delay. Simultaneously, the use of stronger anti-interference protocols and encryption algorithms further improves the security and stability of data transmission.

[0038] Furthermore, the remote monitoring platform integrates artificial intelligence and / or machine learning algorithms to analyze partial discharge data, predict fault types, and estimate the remaining lifespan of the equipment under test. Specifically, to further enhance the system's intelligence, the data analysis and fault location functions of the monitoring system can be optimized. Artificial intelligence (AI) and machine learning (ML) algorithms are integrated into the remote monitoring platform, utilizing historical and real-time data for intelligent analysis. The system can automatically identify patterns in partial discharge, predict and locate fault types. By analyzing historical data from cable terminals, the system can also predict the remaining lifespan of the equipment and provide maintenance recommendations based on partial discharge trends.

[0039] The principles of this invention will be explained in detail below:

[0040] This invention utilizes a flexible sensor array to efficiently and accurately monitor partial discharge phenomena at cable terminals, offering advantages such as high sensitivity, low cost, ease of installation, and strong anti-interference capabilities. By designing a flexible sensor array that adapts to the curved and semi-conductive surfaces of cable terminals, it overcomes the poor adaptability of existing TEV sensors. The flexible sensor array consists of multiple sensor units 2, each employing a dual-capacitor structure, enabling stable operation in the complex environment of cable terminals. The sensor array monitors partial discharge phenomena in real time by detecting the transient ground voltage (TEV) signal on the surface of the cable terminal and transmits the monitoring data to a remote monitoring platform via a wireless communication module, achieving online monitoring and remote management.

[0041] like Figure 2 As shown, when partial discharge occurs at a cable termination, electromagnetic waves propagate from the discharge point in the form of transient voltages. Due to the skin effect, transient voltages inside the metal cannot be directly detected from the external surface. However, electromagnetic waves can propagate into the free space within the metal where electrical discontinuities exist, generating a series of transient voltage spikes on the surrounding metal surface. When partial discharge (PD) occurs inside an electrical device (simplified as a box), electromagnetic waves are emitted; electromagnetic waves leaking from the dielectric discontinuities may propagate to the ground through the surface of the shielding layer in the form of locally elevated voltages (dashed lines); these voltages can be obtained by capacitive sensors and recorded as TEV signals.

[0042] like Figure 3As shown, since the semiconductor coating on the cable terminal is isotropic, the electromagnetic waves generated by partial discharge will propagate in all directions along the surface. For simplicity, the propagation process of the electromagnetic wave from the discharge point to the inner surface of the sheath is recorded as wave process 0. When the electromagnetic wave reaches the outer sheath, it induces a current pulse in the semiconductor material. There are two paths for the pulse to flow to the ground. One pulse flows directly to the ground along the inner surface of the sheath, marked as wave process 1. The other pulse (wave process 2) first reaches the end of the cable terminal (protective back cover) along the inner surface of the sheath, then escapes from the inner surface of the sheath to the semiconductor coating, and then continues to propagate along the coating to the grounding plate, finally reaching the ground through the grounding plate and the ground wire. Through the above analysis, the electromagnetic wave propagation of the cable terminal can be represented as wave processes 0, 1, and 2, and the wave processes can be handled using a transmission line model.

[0043] Based on lumped parameter equivalent circuit analysis, such as Figure 4 As shown, the electromagnetic wave propagation process at the cable termination can be simplified as follows: Figure 5 As shown. Along the Z1 direction, the current pulse will pass through two media: the inner surface of the cable termination and the grounding steel plate. The corresponding surge impedances of these two media are recorded as Z... s1 and Z g1 Where Z1 = Z s1 +Z g1 Similarly, Z2 = Z s2 +Z g2 This represents the equivalent wave impedance from the inner surface to the protective back cover and then to the ground electrode 23.

[0044] The pulse duration of TEV sensors (PDs) on cable terminals can range from a few nanoseconds to hundreds of nanoseconds. Due to its leading advantages such as low electromagnetic interference and high signal-to-noise ratio, the UHF method has been widely used for PD detection. However, this method requires a high sampling rate, so the hardware cost for processing and storing such large amounts of data (e.g., in power distribution networks) can be very high. Therefore, considering the advantages of low cost, high sensitivity, wide bandwidth, ease of installation, and indirect contact detection, we employ a capacitive sensor to capture TEV pulses. Figure 6As shown, in a traditional TEV sensor, the voltage across the capacitor cannot change abruptly. After passing through the capacitor, the square wave becomes an exponential wave, and the wavefront refracted through node A can only gradually increase during capacitor charging. Therefore, when the TEV sensor is connected to the device surface, the rising edge of the pulse flattens, and the high-frequency components in the wave attenuate. Thus, the TEV sensor behaves like a second-order RLC low-pass filter. R represents the series and parallel resistances, C represents the coupling capacitance, and L represents the inductance of the sensor and the inductance of the high-frequency signal cable 3. Typically, the total inductance L can be ignored, and the filter can be further simplified to an RC low-pass filter. When the capacitance C is too small, the effect of the inductance needs to be considered. Based on the above analysis, the most important part of the TEV sensor is the coupling capacitance. Therefore, the coupling area and the inter-electrode distance are the main factors affecting sensor performance. Thus, when applying a traditional TEV sensor to a cable terminal, the small coupling area due to the curved surface and the instability of sensitivity due to the installation process are key issues.

[0045] To reduce the impact of installation and improve the sensitivity of the TEV sensor, this invention designs a dual-capacitor series sensor inspired by differential structures, such as... Figure 7 As shown, the sensor itself is designed as a complete capacitor with two electrodes (called self-capacitance). During detection, the electrode at one end of the dielectric is connected to the cable terminal surface. To prevent the sensor electrodes from directly contacting the cable terminal surface and causing discharge to ground, the entire sensor is sealed with a plastic film, and signal lines are only led out from the electrodes. The electrode closest to the cable terminal serves as the signal output, and the other electrode is grounded. When the sensor is connected to the cable terminal surface, the air gap between the output electrode 21 and the cable terminal surface constitutes another capacitance (called mutual capacitance). Using the innovative TEV sensor design effectively reduces frequency band degradation problems caused during sensor installation and achieves higher and more stable detection sensitivity.

[0046] To improve generalization performance, one feasible embodiment of the present invention employs a sensor array comprising four sensor elements to capture the TEV signal. The output waveform of the sensor array is the ensemble average of each sensor element, such as... Figure 1 As shown. Generally, sensor arrays are more robust in capturing PD signals at any location compared to a single sensor. Furthermore, different waveform propagation paths between the PD source and the sensor will result in different signal attenuation, thus producing different signal amplitudes. Therefore, the sensor should be placed as close to the protective cover as possible to reduce propagation distance.

[0047] The present invention, employing the above technical solutions, has the following beneficial effects: 1) Significantly improves the adaptability and sensitivity to the detection of curved cable terminal structures: Traditional TEV sensors, based on rigid structures, are difficult to fit into semi-conductive curved surfaces, resulting in low signal acquisition efficiency. The present invention uses flexible polymer materials and a dual-capacitor structure, allowing the sensor array to fit tightly into the curved surface of the cable terminal, increasing the effective coupling area. Through simulation and experimental verification, the present invention improves sensitivity by more than 30% compared to traditional TEV sensors and can stably capture nanosecond-level partial discharge pulses. 2) Enhances signal stability and accuracy through the dual-capacitor structure and signal processing technology: The dual-capacitor structure (self-capacitance and mutual capacitance in series) designed in the present invention can suppress sensitivity fluctuations caused by small changes in installation position and reduce the risk of frequency band degradation. Combined with wavelet transform filtering algorithms, it effectively separates environmental noise and partial discharge signals. Experiments show that under the same electromagnetic interference environment, the signal-to-noise ratio of the present invention is improved by about 40%, and the false alarm rate is reduced to below 5%. 3) Significantly reduced hardware costs and simplified installation: Compared to UHF / VHF methods requiring high-frequency sampling hardware, this invention uses low-cost flexible electrode materials and standard RC filter circuits, reducing hardware costs by 50%. The sensor array supports modular installation, requiring no special tools, shortening installation time by 40%, and is suitable for large-scale power distribution network deployments. 4) Strong anti-interference capability based on TEV mechanism ensures data reliability: This invention utilizes the propagation characteristics of transient ground voltage on semiconductor surfaces, avoiding direct contact with high-voltage components and naturally shielding common-mode electromagnetic interference. Comparative tests show that under transient interference from 10kV switch operation, the signal distortion of this invention is less than 1 / 3 of that of traditional high-frequency methods, and data reliability is improved by 30%. 5) Integrated wireless communication enables real-time monitoring and intelligent early warning: Through 4G / 5G wireless modules and cloud platform integration, this invention supports millisecond-level data upload and remote diagnostics. Historical data shows that the system can advance fault warning time by 20%, reducing power outages caused by sudden insulation faults and preventing economic losses exceeding one million yuan annually.

[0048] Obviously, the described embodiments are only a part of the embodiments of this application, not all of them. Without conflict, the embodiments and features in the embodiments of this application can be combined with each other. The components of the embodiments of this application described and illustrated herein can generally be arranged and designed in various different configurations. Therefore, the detailed description of the embodiments of this application is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

Claims

1. A flexible sensor array based on transient ground voltage for online monitoring of partial discharge at cable terminals, characterized in that: The flexible sensor array includes: The housing is made of a flexible polymer material with a curved structure that adapts to the surface of the cable termination. Multiple sensor units are spaced apart on the surface of the housing and detect the TEV signal on the surface of the cable terminal through capacitive coupling. The signal cable is electrically connected at one end to the sensor unit on the housing, and at the other end to the signal processing module and wireless communication module at the rear, enabling real-time transmission and remote monitoring of partial discharge signals.

2. The flexible sensor array based on transient ground voltage according to claim 1, characterized in that: The curved surface structure is a ring structure with an opening.

3. The flexible sensor array based on transient ground voltage according to claim 1, characterized in that: Each sensor unit adopts a dual-capacitor series sensor structure, and each sensor unit includes an output electrode, an intermediate layer and a ground electrode stacked sequentially in a sealed and insulating package. The output electrode, intermediate layer, and ground electrode are arranged from near to far from the cable terminal surface; a self-capacitance is formed between the output electrode and the ground electrode; An air gap between the output electrode and the cable terminal surface forms an interactive capacitance; the output electrode and the ground electrode extend from a sealed insulating enclosure through the lead-out signal line.

4. A flexible sensor array based on transient ground voltage according to claim 3, characterized in that: The sealed and insulating enclosure is a plastic film.

5. A flexible sensor array based on transient ground voltage according to claim 1, characterized in that: Multiple sensor units are arranged in an array to cover different parts of the cable terminal surface, thereby improving detection coverage and sensitivity.

6. A flexible sensor array based on transient ground voltage according to claim 1, characterized in that: The four sensor units are evenly distributed on the inner side of the housing, close to the surface of the cable terminal.

7. A flexible sensor array based on transient ground voltage according to claim 1, characterized in that: The wireless communication module uses a 4G or 5G communication module with high-speed data transmission and anti-interference protocol to upload monitoring data to the remote monitoring platform in real time.

8. A flexible sensor array based on transient ground voltage according to claim 7, characterized in that: The remote monitoring platform integrates artificial intelligence and / or machine learning algorithms to analyze partial discharge data, predict fault types, and estimate the remaining lifespan of the device under test.

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