Partial discharge signal enhancement system and method

Abstract

The invention discloses a partial discharge signal enhancement system and method, and belongs to the technical field of high-voltage cable partial discharge signal enhancement, the method comprises a signal acquisition and enhancement module and a signal bridging module, the signal bridging module is used for forming a partial discharge signal bridging channel for electrically connecting a first cable aluminum sheath and a second cable aluminum sheath, and the signal acquisition and enhancement module is connected with the signal acquisition and enhancement module. A cable bridging signal is transmitted through the partial discharge signal bridging channel; and the signal acquisition and enhancement module is used for acquiring a cable bridging signal, performing power amplification on the cable bridging signal to acquire an enhanced partial discharge signal when the cable bridging signal is judged to be a partial discharge signal based on a preset voltage amplitude, and injecting the enhanced partial discharge signal into the partial discharge signal bridging channel to realize compensation for attenuation of the partial discharge signal. According to the partial discharge signal enhancement system and method disclosed by the invention, enhancement of the partial discharge signal is realized, and a basis is provided for realizing accurate detection and positioning of the partial discharge signal.

Description

Technical Field

[0001] This invention relates to the field of partial discharge signal enhancement technology for high-voltage cables, and more particularly to a partial discharge signal enhancement system and method. Background Technology

[0002] With the advent of the intelligent and information-based era, electricity has become an indispensable energy source in people's daily lives, and the reliability of power supply is crucial to people's daily life and production. In urban power distribution networks, power cables of various voltage levels gradually form a complex distribution network. Among them, power cables are typical capacitive electrical equipment; local insulation damage will lead to the failure of the entire insulation system. Monitoring the condition of cable insulation is crucial to the safe and stable operation of the urban power system. In current cable partial discharge detection work, the location of partial discharge is particularly important. Existing partial discharge location technology mainly relies on the time difference method, that is, by installing partial discharge sensors at multiple intermediate joints of the cable for online monitoring. When a partial discharge occurs at a certain location within the cable, its partial discharge signal will be transmitted along the cable body, thus generating a time difference. By using this time difference for inverse calculation, the location information of the discharge source can be obtained, and the location can be completed.

[0003] However, in routine maintenance, since most cables are installed using methods such as direct burial or duct laying, partial discharge location often requires installing detection devices at the cable ends on both sides. This method places extremely high demands on signal transmission attenuation. Furthermore, while partial discharge location can effectively calculate the location of the discharge source, power cable designs primarily focus on determining parameters for 50Hz power frequency signals, neglecting the transmission of high-frequency signals within the cable. The center frequency of partial discharge signals is often higher than 1MHz. When this high-frequency signal transmits within the power cable, it is attenuated due to leakage current within the cable body and the unevenness of the cable's multi-layered shielding structure. Especially when the partial discharge signal reaches the cable joint, a significant impedance mismatch occurs. Moreover, the intrinsic impedance of the cable body is approximately 30-50 ohms, while the wave impedance of the joint may exceed 1k ohms. This huge difference in transmission impedance causes significant signal reflection, reducing the forward-transmitting signal energy and resulting in substantial attenuation. Current research indicates that when the frequency of a partial discharge signal is 10MHz, its effective transmission distance within a power cable is less than 1km. When intermediate joints are present, this distance drops to several hundred meters. However, the actual length between two intermediate joints in a power cable is approximately 500-700m. This suggests that the transmission of a partial discharge signal can only traverse 2-3 intermediate joints. When the cable length is large, it becomes impossible to effectively measure the partial discharge signal at both ends of the cable, leading to the failure of partial discharge localization. Summary of the Invention

[0004] This invention provides a partial discharge signal enhancement system and method, which can solve the technical problem in the prior art that when the cable length is large, it is impossible to effectively measure the partial discharge signal at the two ends of the cable, resulting in the failure of partial discharge positioning. The invention enhances the partial discharge signal and provides a foundation for the accurate detection and positioning of partial discharge signals.

[0005] This invention provides a partial discharge signal enhancement system applied to a cable joint area. The cable joint area includes a first cable aluminum sheath, a second cable aluminum sheath, and a cable joint. The first and second cable aluminum sheaths are electrically interconnected via the cable joint. The system includes a signal acquisition and enhancement module and a signal bridging module, wherein: The first end of the signal bridging module is electrically connected to the aluminum sheath of the first cable, and the second end of the signal bridging module is electrically connected to the aluminum sheath of the second cable. The first end of the signal acquisition enhancement module is electrically connected to the first end of the signal bridging module, and the second end of the signal acquisition enhancement module is electrically connected to the second end of the signal bridging module. The signal bridging module is used to form a partial discharge signal bridging channel that electrically connects the first cable aluminum sheath and the second cable aluminum sheath, so as to transmit cable bridging signals through the partial discharge signal bridging channel. The signal acquisition and enhancement module is used to acquire the cable bridging signal. When the cable bridging signal is determined to be a partial discharge signal based on a preset voltage amplitude, the power of the cable bridging signal is amplified to acquire the enhanced partial discharge signal, and the enhanced partial discharge signal is injected into the partial discharge signal bridging channel to compensate for the attenuation of the partial discharge signal.

[0006] This invention provides a partial discharge signal enhancement system. A signal bridging module connects the aluminum sheaths of a first and second cable to construct a partial discharge signal bridging channel. This specifically addresses the problem that cross-connection structures at cable joints may cause partial discharge signals to be shunted to other phases, ensuring that the partial discharge signal is transmitted along the same phase aluminum sheath. After acquiring the cable bridging signal, the signal acquisition and enhancement module determines the partial discharge signal based on a preset voltage amplitude. The enhanced partial discharge signal is then amplified and injected into the bridging channel, effectively compensating for the attenuation of the partial discharge signal during transmission within the cable body and at intermediate joints due to impedance mismatch. This allows the partial discharge signal, which was originally limited in transmission distance, to continue forward transmission. This solves the technical problem in existing technologies where, when the cable length is large, it is impossible to effectively measure the partial discharge signal at both ends of the cable, leading to partial discharge location failure. This system enhances the partial discharge signal, providing a foundation for accurate detection and location of partial discharge signals at cable ends.

[0007] Further, the signal acquisition and enhancement module is used to acquire the cable bridging signal. When the cable bridging signal is determined to be a partial discharge signal based on a preset voltage amplitude, the module amplifies the power of the cable bridging signal to acquire an enhanced partial discharge signal, and injects the enhanced partial discharge signal into the partial discharge signal bridging channel, including: Obtain the cable bridging signal; When the cable bridging signal is determined to be a partial discharge signal based on a preset voltage amplitude, a signal delay enhancement action is performed based on a preset delay signal. The signal delay enhancement action includes: Delay control is applied to the cable bridging signal to obtain the delayed partial discharge signal; The delayed partial discharge signal is amplified to obtain an enhanced partial discharge signal, and the enhanced partial discharge signal is injected into the partial discharge signal bridging channel.

[0008] In the above scheme, a signal delay enhancement action is added by the signal acquisition enhancement module. When the cable bridging signal is determined to be a partial discharge signal, the power is amplified and injected into the bridging after the delay control is performed based on the preset delay signal. This avoids the amplified signal after enhancement from overlapping with the original partial discharge signal, prevents signal distortion caused by mutual interference, and ensures that the enhanced partial discharge signal maintains clear characteristics. This provides a high-quality signal source for the subsequent terminal to identify effective signals and perform correlation analysis, thereby improving the accuracy of partial discharge signal detection.

[0009] Furthermore, the signal acquisition and enhancement module is also used for: Acquire historical partial discharge signal data, and determine the first fixed delay that meets the preset periodic conditions based on the historical partial discharge signal data; The signal delay enhancement action is performed based on the initial fixed delay to obtain the actual execution delay; The actual execution delay is used as a preset delay signal.

[0010] In the above scheme, the first fixed delay that meets the preset period conditions is determined by acquiring historical partial discharge signal data. Then, the actual execution delay is used as the preset delay signal. The signal is adapted in combination with the historical partial discharge signal characteristics of the specific cable to ensure that the delay time is accurately matched with the actual partial discharge signal period. This further reduces the risk of superposition between the enhanced signal and the original signal, improves the pertinence and reliability of delay control, and enables cables under different operating conditions to obtain the appropriate signal enhancement effect.

[0011] Furthermore, the signal acquisition and enhancement module includes a signal acquisition submodule, a signal enhancement submodule, and a signal injection submodule, wherein: The first end of the signal acquisition submodule is electrically connected to the aluminum sheath of the first cable, the second end of the signal acquisition submodule is electrically connected to the first end of the signal bridging module, and the third end of the signal acquisition submodule is electrically connected to the first end of the signal enhancement submodule. The second end of the signal enhancement submodule is electrically connected to the first end of the signal injection submodule; The second end of the signal injection submodule is electrically connected to the second end of the signal bridging module; The signal acquisition submodule is used to form a partial discharge signal bridging channel with the signal bridging module to electrically connect the first cable aluminum sheath and the second cable aluminum sheath, so as to transmit the cable bridging signal through the partial discharge signal bridging channel; The signal enhancement submodule is used to amplify the power of the cable bridging signal to obtain an enhanced partial discharge signal when the cable bridging signal is determined to be a partial discharge signal based on a preset voltage amplitude, and then transmit the enhanced partial discharge signal to the signal injection submodule. The signal injection submodule is used to inject the enhanced partial discharge signal into the partial discharge signal bridging channel to compensate for the attenuation of the partial discharge signal.

[0012] In the above scheme, the signal acquisition submodule and the signal bridging module work together to construct a partial discharge signal bridging channel, ensuring stable signal transmission; the signal enhancement submodule focuses on the determination and power amplification of the partial discharge signal, improving the accuracy of signal processing; and the signal injection submodule is specifically responsible for injecting the enhanced partial discharge signal into the bridging channel, ensuring the stability of the injection process. This effectively improves the efficiency of signal transmission, processing, and injection.

[0013] Furthermore, the signal enhancement submodule includes a signal acquisition unit, a signal buffer unit, and a signal generation unit, wherein: The first end of the signal acquisition unit serves as the first end of the signal enhancement submodule. The second end of the signal acquisition unit is electrically connected to the first end of the signal buffer unit. The second end of the signal buffer unit is electrically connected to the first end of the signal generation unit. The second end of the signal generation unit serves as the second end of the signal enhancement submodule. The signal acquisition unit is used to sample and convert the cable bridging signal to obtain a partial discharge digital signal; The signal buffer unit is used to judge the cable bridging signal based on the preset voltage amplitude and the partial discharge digital signal. When the cable bridging signal is determined to be a partial discharge signal, the partial discharge digital signal is transmitted to the signal generation unit. The signal generation unit is used to convert the partial discharge digital signal into an analog voltage signal and output it to the signal injection submodule.

[0014] In the above scheme, the cable bridging signal is sampled and converted into a partial discharge digital signal by the signal acquisition unit, ensuring that the original characteristics of the signal are preserved during processing; the partial discharge signal is determined by the signal buffer unit based on a preset voltage amplitude, filtering out non-partial discharge interference signals to avoid invalid signals occupying processing resources; the digital signal is converted into an analog voltage signal by the signal generation unit and output, ensuring that the enhanced signal is consistent with the waveform characteristics of the original partial discharge signal. This reduces signal distortion, improves the fidelity of the enhanced partial discharge signal, and provides a reliable guarantee for subsequent signal correlation analysis and signal pair matching at the terminal.

[0015] Furthermore, it also includes: The signal enhancement submodule is electrically connected to the first terminal of the signal bridging module via a reference ground line. The reference ground line is used to receive the reverse signal from the partial discharge signal bridging channel and transmit it to the signal enhancement submodule to achieve reverse transmission suppression.

[0016] In the above scheme, the reference ground of the signal enhancement submodule is electrically connected to the first end of the signal bridging module. This ensures that when the enhanced partial discharge signal is injected into the partial discharge signal bridging channel, the reverse-transmitted overlapping partial discharge signal will flow back to the signal enhancement module through the reference ground and cannot enter the signal acquisition submodule. This effectively suppresses the reverse transmission of the enhanced signal, avoids errors caused by multiple reflections of the signal in the cable, and ensures that the original partial discharge signal acquired by the signal acquisition submodule is not subject to reverse interference, further improving the stability and purity of the partial discharge signal transmission.

[0017] Furthermore: the signal acquisition and enhancement module includes an A-phase signal acquisition and enhancement module, a B-phase signal acquisition and enhancement module, and a C-phase signal acquisition and enhancement module; the signal bridging module includes an A-phase signal bridging module, a B-phase signal bridging module, and a C-phase signal bridging module; For any one of the following signal acquisition and enhancement modules and signal bridging modules that are in the same phase: Phase A signal acquisition and enhancement module, Phase B signal acquisition and enhancement module, Phase C signal acquisition and enhancement module, Phase A signal bridging module, Phase B signal bridging module and Phase C signal bridging module: The first end of the signal bridging module is electrically connected to the corresponding phase aluminum sheath of the first cable, and the second end of the signal bridging module is electrically connected to the corresponding phase aluminum sheath of the second cable. The first end of the signal acquisition enhancement module is electrically connected to the first end of the signal bridging module, and the second end of the signal acquisition enhancement module is electrically connected to the second end of the signal bridging module. The signal bridging module is used to form a current phase partial discharge signal bridging channel that electrically connects the aluminum sheath of the corresponding phase of the first cable and the aluminum sheath of the corresponding phase of the second cable, so as to transmit the current phase cable bridging signal through the current phase partial discharge signal bridging channel; The signal acquisition and enhancement module is used to acquire the current phase cable bridging signal. When the current phase cable bridging signal is determined to be a partial discharge signal based on a preset voltage amplitude, the current phase cable bridging signal is amplified to acquire the current phase enhanced partial discharge signal, and the current phase enhanced partial discharge signal is injected into the partial discharge signal bridging channel to compensate for the attenuation of the partial discharge signal.

[0018] In the above scheme, corresponding signal acquisition and enhancement modules and signal bridging modules are configured for phases A, B, and C respectively. Each phase independently constructs a partial discharge signal bridging channel and performs signal processing. It adapts to the cross-interconnection structure of the three-phase cable, ensuring that the partial discharge signal of each phase is transmitted and enhanced in a dedicated channel, avoiding signal interference between phases, so that the partial discharge signal of each phase of the three-phase cable can be compensated for in a targeted manner, thus expanding the applicability of the system.

[0019] This invention provides a partial discharge signal enhancement system. By constructing a dedicated single-phase partial discharge signal bridging channel, it solves the signal shunting problem caused by the cross-interconnection structure of three-phase cables. Through precise modular processing of the partial discharge signal, it effectively compensates for the transmission attenuation of the partial discharge signal at the cable body and intermediate joints, enabling the partial discharge signal, which originally could only be transmitted for a few hundred meters, to be continuously transmitted to the terminal of long-distance cables. Simultaneously, by combining a reference ground wire design to suppress the reverse transmission of the enhanced signal and delay control to avoid signal aliasing, it ensures the fidelity and transmission stability of the enhanced signal. Ultimately, this solution solves the problem in existing technologies where the partial discharge signal of long-distance high-voltage cables cannot be transmitted far and the terminal cannot be detected, leading to positioning failure. It provides a reliable signal guarantee for cable insulation condition monitoring and can effectively improve the safety and stability of urban power distribution network cable operation.

[0020] This invention also provides a partial discharge signal enhancement method, applied to a partial discharge signal enhancement system. The partial discharge signal enhancement system includes a signal acquisition and enhancement module and a signal bridging module. The signal bridging module is used to form a partial discharge signal bridging channel electrically connecting a first cable aluminum sheath and a second cable aluminum sheath. The method uses the signal acquisition and enhancement module as the executing entity and includes: The cable bridging signal is acquired. When the cable bridging signal is determined to be a partial discharge signal based on a preset voltage amplitude, the power of the cable bridging signal is amplified to acquire an enhanced partial discharge signal. The enhanced partial discharge signal is output to compensate for the attenuation of the partial discharge signal.

[0021] This invention provides a partial discharge signal enhancement method. By acquiring the cable bridging signal, determining the partial discharge signal, amplifying the power, and then merging the enhanced partial discharge signal with the original signal for output, the method directly compensates for the attenuation of the partial discharge signal. Focusing on the core requirement of signal enhancement, this method achieves rapid response to the partial discharge signal and timely compensation for signal attenuation, enabling continuous transmission of the partial discharge signal over long-distance cables. This solves the problem in existing technologies where the partial discharge signal over long-distance cables cannot reach the terminal, providing the necessary conditions for partial discharge location.

[0022] Further, the step of acquiring the cable bridging signal based on the partial discharge signal bridging channel, and when determining that the cable bridging signal is a partial discharge signal based on a preset voltage amplitude, amplifying the power of the cable bridging signal to obtain an enhanced partial discharge signal, includes: The cable bridging signal is obtained based on the partial discharge signal bridging channel; When the cable bridging signal is determined to be a partial discharge signal based on a preset voltage amplitude, a signal delay enhancement action is performed based on a preset delay signal. The signal delay enhancement action includes: Delay control is applied to the cable bridging signal to obtain the delayed partial discharge signal; The delayed partial discharge signal is amplified to obtain an enhanced partial discharge signal, and the enhanced partial discharge signal is injected into the partial discharge signal bridging channel.

[0023] Furthermore, it also includes: Acquire historical partial discharge signal data, and determine the first fixed delay that meets the preset periodic conditions based on the historical partial discharge signal data; The signal delay enhancement action is performed based on the initial fixed delay to obtain the actual execution delay; The actual execution delay is used as a preset delay signal.

[0024] This invention provides a partial discharge signal enhancement method that effectively compensates for the transmission attenuation of the partial discharge signal at the cable body and intermediate joints by enhancing the acquisition of the partial discharge signal. This allows the partial discharge signal, which could originally only be transmitted for a few hundred meters, to be continuously transmitted to the terminal of a long-distance cable. At the same time, combined with delay control to avoid signal aliasing, it ensures the fidelity and transmission stability of the enhanced signal. This solves the problem in the prior art that the partial discharge signal of long-distance high-voltage cables cannot be transmitted far and the terminal cannot be detected, resulting in positioning failure. It provides a reliable signal guarantee for cable insulation status monitoring and can effectively improve the safety and stability of urban power distribution network cable operation. Attached Figure Description

[0025] To more clearly illustrate the technical solution of this application, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0026] Figure 1 This is a schematic diagram of a single-phase connected partial discharge signal enhancement system provided in this embodiment; Figure 2 This is a schematic diagram of a partial discharge signal enhancement device provided in this embodiment; Figure 3 This is a schematic diagram of a partial discharge signal enhancement device connected to a reference ground wire provided in this embodiment; In the diagram: 1. First cable aluminum sheath; 2. Second cable aluminum sheath; 3. Cable connector; 4. Signal bridging module; 5. Signal acquisition and enhancement module; 6. Partial discharge signal bridging channel; 7. Signal enhancement submodule; 8. Reference ground wire; 01. First cable; 02. Second cable. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of this application will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0028] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0029] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.

[0030] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0031] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0032] In the description of the embodiments of this application, the term "multiple" refers to two or more (including two), similarly, "multiple sets" refers to two or more (including two sets), and "multiple pieces" refers to two or more (including two pieces).

[0033] In the description of the embodiments of this application, unless otherwise expressly specified and limited, technical terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.

[0034] This embodiment provides a partial discharge signal enhancement system applied to a cable joint area. The cable joint area includes a first cable aluminum sheath, a second cable aluminum sheath, and a cable joint. The first and second cable aluminum sheaths are electrically interconnected via the cable joint. The system includes a signal acquisition and enhancement module and a signal bridging module, wherein: The first end of the signal bridging module is electrically connected to the aluminum sheath of the first cable, and the second end of the signal bridging module is electrically connected to the aluminum sheath of the second cable. The first end of the signal acquisition enhancement module is electrically connected to the first end of the signal bridging module, and the second end of the signal acquisition enhancement module is electrically connected to the second end of the signal bridging module. The signal bridging module is used to form a partial discharge signal bridging channel that electrically connects the first cable aluminum sheath and the second cable aluminum sheath, so as to transmit cable bridging signals through the partial discharge signal bridging channel. The signal acquisition and enhancement module is used to acquire the cable bridging signal. When the cable bridging signal is determined to be a partial discharge signal based on a preset voltage amplitude, the power of the cable bridging signal is amplified to acquire the enhanced partial discharge signal, and the enhanced partial discharge signal is injected into the partial discharge signal bridging channel to compensate for the attenuation of the partial discharge signal.

[0035] In the specific implementation process, in order to determine whether the pulse signals synchronously acquired from both ends of the cable belong to the same partial discharge, signal correlation analysis is used to determine the matching signal pairs, which requires enhancement processing of the partial discharge signal. Specifically, when synchronously acquiring signals from both ends of a long-distance cable, a high-frequency partial discharge signal flowing from the second end to the first end of the long-distance cable is detected at the first end, i.e., a pulse signal caused by partial discharge is detected. However, the pulse signal caused by the partial discharge cannot be detected at the second end, indicating that there may be a partial discharge source between the first and second ends of the long-distance cable. This partial discharge source transmits to both sides, generating partial discharge signals flowing from the second end to the first end and from the first end to the second end of the long-distance cable in two directions. It is preliminarily determined that the high-frequency partial discharge signal is attenuated between the first and second ends of the cable (i.e., the partial discharge signal flowing from the first end to the second end of the long-distance cable is attenuated between the partial discharge source and the second end of the long-distance cable). At this point, the partial discharge signal enhancement system provided in this embodiment is electrically connected to the first cable joint area near the second end of the long-distance cable between the first end and the second end of the long-distance cable to enhance the signal. If, after adding the system, the pulse signal caused by partial discharge still cannot be detected at the second end of the long-distance cable, then the partial discharge signal enhancement system is set to the second cable joint area near the second end of the long-distance cable. This process continues until the pulse signal caused by partial discharge can be detected at the second end of the long-distance cable. At this point, it is determined that there may be a partial discharge source between the first end and the second end of the long-distance cable. Subsequently, the pulse signals detected at both ends of the long-distance cable are used to perform time difference positioning calculations to achieve accurate positioning of the partial discharge.

[0036] In practical implementation, since the aluminum sheaths of the cables at both ends of the cable joint area need to be grounded through grounding leads, the partial discharge signal enhancement system provided in this embodiment can be directly electrically connected to the grounding leads of the aluminum sheaths at both ends of the cable, without needing to locate the cable body. It should be noted that the partial discharge signal enhancement system provided in this embodiment achieves single-phase partial discharge signal enhancement. Therefore, during installation, the installation direction of this system should be set according to the direction of the pulse signal detected at one end of the long-distance cable. For example, based on the pulse signal, it can be known that the direction of the high-frequency partial discharge signal is from left to right relative to the cable joint area. Then, the left side of the cable joint area is taken as the first cable, and the right side of the cable joint area is taken as the second cable, thereby defining the first and second cable aluminum sheaths.

[0037] In practical implementation, the above-mentioned partial discharge enhancement process can be achieved by adding one or more partial discharge signal enhancement systems provided in this embodiment. Compared with the need to install multiple partial discharge sensors at multiple intermediate joints of the cable for online monitoring, this solution is more advantageous in actual engineering implementation. It can solve the problem of ineffective detection and accurate positioning of partial discharge signals in long-distance cables due to transmission attenuation without adding a large number of fixed sensors or damaging the cable joints. It has outstanding advantages such as low cost, simple construction, high positioning accuracy, and mobility and reusability, which is significantly better than the traditional solution of directly deploying sensors at each cable joint.

[0038] Specifically, taking any one of the phases A, B, and C of a high-voltage cable line cable joint area as an example, this embodiment provides a partial discharge signal enhancement system connected to a single phase of that phase cable, such as... Figure 1As shown, the first cable 01 and the second cable 02 of this phase cable are electrically connected at the intermediate joint of the high-voltage cable through the cable connector 3 of this phase. To ensure that the partial discharge signal is transmitted along the aluminum sheath of the same phase, this embodiment uses a signal bridging module 4 to connect the first cable aluminum sheath 1 and the second cable aluminum sheath 2 of the same phase cable to form a partial discharge signal bridging channel 6. A signal acquisition and enhancement module 5 is then set up to enhance the partial discharge signal. It should be noted that the connection method of the other two phase cables is the same as that of this phase cable. Meanwhile, the A-phase cable, B-phase cable, and C-phase cable are connected using a cross-interconnection structure. Specifically, the cross-interconnection structure is as follows: the first cable aluminum sheath 1 of the A-phase cable is connected to the second cable aluminum sheath 2 of the B-phase cable, the first cable aluminum sheath 1 of the B-phase cable is connected to the second cable aluminum sheath 2 of the C-phase cable, and the first cable aluminum sheath 1 of the C-phase cable is connected to the second cable aluminum sheath 2 of the A-phase cable, thus forming a typical cross-interconnection structure to cancel the induced current in the aluminum sheaths of each phase cable. However, this cross-connection structure will cause a change in the transmission path of the partial discharge signal. When the partial discharge signal of the aluminum sheath is transmitted to the intermediate joint position, it will enter the grounded aluminum sheath of other phase cables to continue transmission. Therefore, in this embodiment, a signal bridging module 4 is set to ensure that the cable partial discharge signal is transmitted along the aluminum sheath of the same phase.

[0039] In practical applications, this embodiment uses a partial discharge signal bridging capacitor C1 as the signal bridging module 4. Because the capacitive reactance decreases at high frequencies, the capacitive reactance of the partial discharge signal (1MHz and higher frequencies) is reduced by five orders of magnitude compared to the capacitive reactance at the power frequency (50Hz). Therefore, the partial discharge signal can continue to be transmitted smoothly through C1. The capacitance value of the partial discharge signal bridging capacitor C1 can be selected in the range of 100pF-10nF to meet the design requirements of this embodiment.

[0040] Optionally, the signal acquisition and enhancement module 5 is used to acquire the cable bridging signal. When the cable bridging signal is determined to be a partial discharge signal based on a preset voltage amplitude, the power of the cable bridging signal is amplified to acquire an enhanced partial discharge signal, and the enhanced partial discharge signal is injected into the partial discharge signal bridging channel 6, including: Obtain the cable bridging signal; When the cable bridging signal is determined to be a partial discharge signal based on a preset voltage amplitude, a signal delay enhancement action is performed based on a preset delay signal. The signal delay enhancement action includes: Delay control is applied to the cable bridging signal to obtain the delayed partial discharge signal; The delayed partial discharge signal is amplified to obtain an enhanced partial discharge signal, and the enhanced partial discharge signal is injected into the partial discharge signal bridging channel 6.

[0041] Optionally, the signal acquisition and enhancement module 5 is further used for: Acquire historical partial discharge signal data, and determine the first fixed delay that meets the preset periodic conditions based on the historical partial discharge signal data; The signal delay enhancement action is performed based on the initial fixed delay to obtain the actual execution delay; The actual execution delay is used as a preset delay signal.

[0042] Optionally, the signal acquisition and enhancement module 5 includes a signal acquisition submodule, a signal enhancement submodule, and a signal injection submodule, wherein: The first end of the signal acquisition submodule is electrically connected to the first cable aluminum sheath 1, the second end of the signal acquisition submodule is electrically connected to the first end of the signal bridging module 4, and the third end of the signal acquisition submodule is electrically connected to the first end of the signal enhancement submodule. The second end of the signal enhancement submodule is electrically connected to the first end of the signal injection submodule; The second end of the signal injection submodule is electrically connected to the second end of the signal bridging module 4; The signal acquisition submodule is used to form a partial discharge signal bridging channel 6 with the signal bridging module 4 to electrically connect the first cable aluminum sheath 1 and the second cable aluminum sheath 2, so as to transmit cable bridging signals through the partial discharge signal bridging channel 6. The signal enhancement submodule is used to amplify the power of the cable bridging signal to obtain an enhanced partial discharge signal when the cable bridging signal is determined to be a partial discharge signal based on a preset voltage amplitude, and then transmit the enhanced partial discharge signal to the signal injection submodule. The signal injection submodule is used to inject the enhanced partial discharge signal into the partial discharge signal bridging channel 6 to compensate for the attenuation of the partial discharge signal.

[0043] In the specific implementation process, this embodiment uses a high frequency current sensor (HFCT) as a signal acquisition submodule. When a partial discharge signal (i.e. the cable bridging signal) passes through the partial discharge signal bridging channel 6, the HFCT sensor will couple to the cable bridging signal and input the cable bridging signal into the signal enhancement submodule.

[0044] In this specific implementation, the signal injection capacitor C2 serves as the signal injection submodule, and both the HFCT for signal acquisition and the signal injection capacitor C2 are connected to the connection line of C1. In practical applications, the two ends of the partial discharge signal bridging channel 6 are electrically connected to the grounding wire of the first cable aluminum sheath 1 and the grounding wire of the second cable aluminum sheath 2, respectively.

[0045] Optionally, the signal enhancement submodule includes a signal acquisition unit, a signal buffer unit, and a signal generation unit, wherein: The first end of the signal acquisition unit serves as the first end of the signal enhancement submodule. The second end of the signal acquisition unit is electrically connected to the first end of the signal buffer unit. The second end of the signal buffer unit is electrically connected to the first end of the signal generation unit. The second end of the signal generation unit serves as the second end of the signal enhancement submodule. The signal acquisition unit is used to sample and convert the cable bridging signal to obtain a partial discharge digital signal; The signal buffer unit is used to judge the cable bridging signal based on the preset voltage amplitude and the partial discharge digital signal. When the cable bridging signal is determined to be a partial discharge signal, the partial discharge digital signal is transmitted to the signal generation unit. The signal generation unit is used to convert the partial discharge digital signal into an analog voltage signal and output it to the signal injection submodule.

[0046] In the specific implementation process, this embodiment uses a high-speed acquisition card as the signal acquisition unit. Its function is to receive the cable bridging signal coupled from the HFCT sensor when there is a cable bridging signal passing through the partial discharge signal bridging channel 6. The high-speed acquisition card will perform sampling conversion at a sampling rate of more than 100MSps to convert the cable bridging signal into a partial discharge digital signal.

[0047] The signal buffer unit in this embodiment is a microcontroller device with storage function, which can store the digital value of the acquired partial discharge signal. After the high-speed acquisition card completes signal acquisition, it determines the signal amplitude based on the signal amplitude. In this embodiment, when the signal voltage amplitude included in the partial discharge digital signal exceeds a preset voltage amplitude U, the signal is considered a partial discharge signal, and the cable bridging signal is determined to be a partial discharge signal, then the subsequent signal enhancement process begins. In specific applications, U can be set based on the historical discharge data value or empirical value of the cable under test.

[0048] Simultaneously, the signal buffer unit can transmit the partial discharge digital signal to the subsequent signal generation unit after a fixed delay according to the delay time setting principle via its internal clock. Specifically: during signal acquisition, the original signal will continue to be transmitted to the right along the partial discharge signal bridging capacitor C1. A reasonable delay time needs to be set for delay control to prevent the amplified signal after enhancement from overlapping with the original signal. According to historical partial discharge signal data of the cable, the waveform of a single partial discharge signal is mostly about 5-10 oscillation cycles, and the total length of a single partial discharge signal generally does not exceed 1µs. Therefore, in this embodiment, the delay time is set to the first fixed delay that meets the preset period condition for the first partial discharge signal enhancement process of the partial discharge signal enhancement system to eliminate the mutual interference between the two signals. After completing this operation, the known actual execution delay ΔT can be obtained, and this actual execution delay can be used as a key parameter for subsequent positioning, such as as a preset delay signal. Specifically, meeting the preset period condition means greater than 1µs.

[0049] In this embodiment, the signal generation unit is a digital-to-analog converter module with signal generation capability. It can convert the partial discharge digital signal transmitted from the signal buffer unit into an analog voltage signal and inject it into the partial discharge signal bridging channel 6 of the transmission line via the signal injection capacitor C2. Specifically, after a delay ΔT, the delayed partial discharge signal formed by the partial discharge digital signal is transmitted to the signal generation unit. This unit includes a DAC (digital-to-analog converter chip) and a power amplifier chip to amplify the delayed partial discharge signal and obtain an enhanced partial discharge signal. The analog voltage of the converted enhanced partial discharge signal has the same waveform characteristics and amplified voltage value as the original partial discharge signal. It can re-enter the transmission path of the partial discharge signal, i.e., inside the aluminum sheath of the cable, through the signal injection capacitor to continue forward transmission.

[0050] In summary, such as Figure 2 As shown, this embodiment provides a partial discharge signal enhancement device, such as... Figure 2 As shown. In practical applications, before powering on the partial discharge signal enhancement device, first connect C2, HFCT, and C1 to the high-voltage cable intermediate joint, and connect the first cable aluminum sheath 1 and the second cable aluminum sheath 2 to form the partial discharge signal bridging channel 6. Then turn on the power to the signal enhancement submodule 7 to put it into the partial discharge signal monitoring and acquisition state.

[0051] Optional, also includes: The signal enhancement submodule 7 is electrically connected to the first end of the signal bridging module 4 via a reference ground line 8. The reference ground line is used to receive the reverse signal from the partial discharge signal bridging channel 6 and transmit it to the signal enhancement submodule 7 to achieve reverse transmission suppression.

[0052] In the specific implementation process, such as Figure 3The partial discharge signal enhancement device shown, connected to a reference ground line, electrically connects the reference ground line 8 of the signal enhancement submodule 7 to the first end of C1, i.e., to the left-side conductor of C1, and uses the potential of this conductor as the reference ground potential. When an enhanced partial discharge signal is injected into the transmission line on the right side of C1 by C2, it will propagate along the transmission line in two directions, left and right. The current propagating to the left will enter the reference ground line 8 via the first current direction d1, thus returning to the reference low potential of the signal enhancement module. Therefore, this current will not re-enter the HFCT; part of the current continues to propagate forward along the second current direction d2.

[0053] Optionally: the signal acquisition and enhancement module 5 includes an A-phase signal acquisition and enhancement module, a B-phase signal acquisition and enhancement module, and a C-phase signal acquisition and enhancement module; the signal bridging module includes an A-phase signal bridging module, a B-phase signal bridging module, and a C-phase signal bridging module; For any one of the following signal acquisition and enhancement modules in the same phase: Phase A signal acquisition and enhancement module, Phase B signal acquisition and enhancement module, Phase C signal acquisition and enhancement module, Phase A signal bridging module, Phase B signal bridging module, and Phase C signal bridging module: The first end of the signal bridging module 4 is electrically connected to the corresponding phase aluminum sheath of the first cable, and the second end of the signal bridging module 4 is electrically connected to the corresponding phase aluminum sheath of the second cable. The first end of the signal acquisition enhancement module 5 is electrically connected to the first end of the signal bridging module 4, and the second end of the signal acquisition enhancement module 5 is electrically connected to the second end of the signal bridging module 4. The signal bridging module 4 is used to form a current phase partial discharge signal bridging channel 6 that electrically connects the aluminum sheath of the corresponding phase of the first cable and the aluminum sheath of the corresponding phase of the second cable, so as to transmit the current phase cable bridging signal through the current phase partial discharge signal bridging channel 6. The signal acquisition and enhancement module 5 is used to acquire the current phase cable bridging signal. When the current phase cable bridging signal is determined to be a partial discharge signal based on a preset voltage amplitude, the current phase cable bridging signal is amplified to acquire the current phase enhanced partial discharge signal, and the current phase enhanced partial discharge signal is injected into the partial discharge signal bridging channel 6 to compensate for the attenuation of the partial discharge signal.

[0054] This embodiment provides a partial discharge signal enhancement system, proposing a method and apparatus for enhancing and compensating for partial discharge signals along a cable line. By installing signal acquisition, amplification, and coupling modules at intermediate joints along the cable, the attenuated partial discharge signal is amplified in real time and reinjected into the cable, solving the problem of undetectable partial discharge signals due to attenuation during transmission. Signal acquisition, amplification, and reinjection can be achieved on artificially constructed partial discharge signal bridging paths, compensating for attenuation of the partial discharge signal in the cable body and at intermediate joints. Simultaneously, delaying the signal enhancement before reinjection prevents signal aliasing interference. By using a reference ground wire 8 to prevent reverse signal transmission, the circuit structure of this embodiment effectively prevents the enhanced signal from being transmitted back to the partial discharge signal, avoiding errors caused by multiple reflections of the partial discharge signal within the cable.

[0055] This embodiment also provides a partial discharge signal enhancement method, applied to a partial discharge signal enhancement system. The partial discharge signal enhancement system includes a signal acquisition and enhancement module and a signal bridging module. The signal bridging module is used to form a partial discharge signal bridging channel that electrically connects the aluminum sheath of a first cable to the aluminum sheath of a second cable. The method uses the signal acquisition and enhancement module as the execution subject and includes: The cable bridging signal is acquired. When the cable bridging signal is determined to be a partial discharge signal based on a preset voltage amplitude, the power of the cable bridging signal is amplified to acquire an enhanced partial discharge signal. The enhanced partial discharge signal is output to compensate for the attenuation of the partial discharge signal.

[0056] Optionally, the step of acquiring the cable bridging signal based on the partial discharge signal bridging channel, and when the cable bridging signal is determined to be a partial discharge signal based on a preset voltage amplitude, amplifying the power of the cable bridging signal to obtain an enhanced partial discharge signal, includes: The cable bridging signal is obtained based on the partial discharge signal bridging channel; When the cable bridging signal is determined to be a partial discharge signal based on a preset voltage amplitude, a signal delay enhancement action is performed based on a preset delay signal. The signal delay enhancement action includes: Delay control is applied to the cable bridging signal to obtain the delayed partial discharge signal; The delayed partial discharge signal is amplified to obtain an enhanced partial discharge signal, and the enhanced partial discharge signal is injected into the partial discharge signal bridging channel.

[0057] Optional, also includes: Acquire historical partial discharge signal data, and determine the first fixed delay that meets the preset periodic conditions based on the historical partial discharge signal data; The signal delay enhancement action is performed based on the initial fixed delay to obtain the actual execution delay; The actual execution delay is used as a preset delay signal.

[0058] The above description represents the preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. A partial discharge signal enhancement system applied to a cable joint area, the cable joint area comprising a first cable aluminum sheath, a second cable aluminum sheath, and a cable joint, wherein the first cable aluminum sheath and the second cable aluminum sheath are electrically interconnected via the cable joint; characterized in that, It includes a signal acquisition and enhancement module and a signal bridging module, wherein: The first end of the signal bridging module is electrically connected to the aluminum sheath of the first cable, and the second end of the signal bridging module is electrically connected to the aluminum sheath of the second cable. The first end of the signal acquisition enhancement module is electrically connected to the first end of the signal bridging module, and the second end of the signal acquisition enhancement module is electrically connected to the second end of the signal bridging module. The signal bridging module is used to form a partial discharge signal bridging channel that electrically connects the first cable aluminum sheath and the second cable aluminum sheath, so as to transmit cable bridging signals through the partial discharge signal bridging channel. The signal acquisition and enhancement module is used to acquire the cable bridging signal. When the cable bridging signal is determined to be a partial discharge signal based on a preset voltage amplitude, the power of the cable bridging signal is amplified to acquire the enhanced partial discharge signal, and the enhanced partial discharge signal is injected into the partial discharge signal bridging channel.

2. The partial discharge signal enhancement system as described in claim 1, characterized in that, The signal acquisition and enhancement module is used to acquire the cable bridging signal. When the cable bridging signal is determined to be a partial discharge signal based on a preset voltage amplitude, the module amplifies the power of the cable bridging signal to acquire an enhanced partial discharge signal, and injects the enhanced partial discharge signal into the partial discharge signal bridging channel, including: Obtain the cable bridging signal; When the cable bridging signal is determined to be a partial discharge signal based on a preset voltage amplitude, a signal delay enhancement action is performed based on a preset delay signal. The signal delay enhancement action includes: Delay control is applied to the cable bridging signal to obtain the delayed partial discharge signal; The delayed partial discharge signal is amplified to obtain an enhanced partial discharge signal, and the enhanced partial discharge signal is injected into the partial discharge signal bridging channel.

3. The partial discharge signal enhancement system as described in claim 2, characterized in that, The signal acquisition and enhancement module is also used for: Acquire historical partial discharge signal data, and determine the first fixed delay that meets the preset periodic conditions based on the historical partial discharge signal data; The signal delay enhancement action is performed based on the initial fixed delay to obtain the actual execution delay; The actual execution delay is used as the preset delay signal.

4. The partial discharge signal enhancement system as described in claim 1, characterized in that, The signal acquisition and enhancement module includes a signal acquisition submodule, a signal enhancement submodule, and a signal injection submodule, wherein: The first end of the signal acquisition submodule is electrically connected to the aluminum sheath of the first cable, the second end of the signal acquisition submodule is electrically connected to the first end of the signal bridging module, and the third end of the signal acquisition submodule is electrically connected to the first end of the signal enhancement submodule. The second end of the signal enhancement submodule is electrically connected to the first end of the signal injection submodule; The second end of the signal injection submodule is electrically connected to the second end of the signal bridging module; The signal acquisition submodule is used to form a partial discharge signal bridging channel with the signal bridging module to electrically connect the first cable aluminum sheath and the second cable aluminum sheath, so as to transmit the cable bridging signal through the partial discharge signal bridging channel; The signal enhancement submodule is used to amplify the power of the cable bridging signal to obtain an enhanced partial discharge signal when the cable bridging signal is determined to be a partial discharge signal based on a preset voltage amplitude, and then transmit the enhanced partial discharge signal to the signal injection submodule. The signal injection submodule is used to inject the enhanced partial discharge signal into the partial discharge signal bridging channel to compensate for the attenuation of the partial discharge signal.

5. A partial discharge signal enhancement system as described in claim 4, characterized in that, The signal enhancement submodule includes a signal acquisition unit, a signal buffer unit, and a signal generation unit, wherein: The first end of the signal acquisition unit serves as the first end of the signal enhancement submodule. The second end of the signal acquisition unit is electrically connected to the first end of the signal buffer unit. The second end of the signal buffer unit is electrically connected to the first end of the signal generation unit. The second end of the signal generation unit serves as the second end of the signal enhancement submodule. The signal acquisition unit is used to sample and convert the cable bridging signal to obtain a partial discharge digital signal; The signal buffer unit is used to judge the cable bridging signal based on the preset voltage amplitude and the partial discharge digital signal. When the cable bridging signal is determined to be a partial discharge signal, the partial discharge digital signal is transmitted to the signal generation unit. The signal generation unit is used to convert the partial discharge digital signal into an analog voltage signal and output it to the signal injection submodule.

6. The partial discharge signal enhancement system as described in claim 4, characterized in that: The signal enhancement submodule is electrically connected to the first terminal of the signal bridging module via a reference ground line. The reference ground line is used to receive the reverse signal from the partial discharge signal bridging channel and transmit it to the signal enhancement submodule to achieve reverse transmission suppression.

7. The partial discharge signal enhancement system as described in claim 1, characterized in that: The signal acquisition and enhancement module includes an A-phase signal acquisition and enhancement module, a B-phase signal acquisition and enhancement module, and a C-phase signal acquisition and enhancement module; The signal bridging module includes an A-phase signal bridging module, a B-phase signal bridging module, and a C-phase signal bridging module; For any one of the following signal acquisition and enhancement modules and signal bridging modules that are in the same phase: Phase A signal acquisition and enhancement module, Phase B signal acquisition and enhancement module, Phase C signal acquisition and enhancement module, Phase A signal bridging module, Phase B signal bridging module and Phase C signal bridging module: The first end of the signal bridging module is electrically connected to the corresponding phase aluminum sheath of the first cable, and the second end of the signal bridging module is electrically connected to the corresponding phase aluminum sheath of the second cable. The first end of the signal acquisition enhancement module is electrically connected to the first end of the signal bridging module, and the second end of the signal acquisition enhancement module is electrically connected to the second end of the signal bridging module. The signal bridging module is used to form a current phase partial discharge signal bridging channel that electrically connects the aluminum sheath of the corresponding phase of the first cable and the aluminum sheath of the corresponding phase of the second cable, so as to transmit the current phase cable bridging signal through the current phase partial discharge signal bridging channel; The signal acquisition and enhancement module is used to acquire the current phase cable bridging signal. When the current phase cable bridging signal is determined to be a partial discharge signal based on a preset voltage amplitude, the current phase cable bridging signal is amplified to acquire the current phase enhanced partial discharge signal, and the current phase enhanced partial discharge signal is injected into the partial discharge signal bridging channel to compensate for the attenuation of the partial discharge signal.

8. A method for enhancing partial discharge signals, characterized in that, The partial discharge signal enhancement system includes a signal acquisition and enhancement module and a signal bridging module. The signal bridging module is used to form a partial discharge signal bridging channel that electrically connects the aluminum sheath of the first cable to the aluminum sheath of the second cable. This method, with the signal acquisition and enhancement module as the execution entity, includes: The cable bridging signal is obtained based on the partial discharge signal bridging channel. When the cable bridging signal is determined to be a partial discharge signal based on a preset voltage amplitude, the power of the cable bridging signal is amplified to obtain an enhanced partial discharge signal. The enhanced partial discharge signal is injected into the partial discharge signal bridging channel.

9. A partial discharge signal enhancement method as described in claim 8, characterized in that, The process of acquiring a cable bridging signal based on the partial discharge signal bridging channel, and when determining that the cable bridging signal is a partial discharge signal based on a preset voltage amplitude, amplifying the power of the cable bridging signal to obtain an enhanced partial discharge signal, includes: The cable bridging signal is obtained based on the partial discharge signal bridging channel; When the cable bridging signal is determined to be a partial discharge signal based on a preset voltage amplitude, a signal delay enhancement action is performed based on a preset delay signal. The signal delay enhancement action includes: Delay control is applied to the cable bridging signal to obtain the delayed partial discharge signal; The delayed partial discharge signal is amplified to obtain an enhanced partial discharge signal, and the enhanced partial discharge signal is injected into the partial discharge signal bridging channel.

10. A partial discharge signal enhancement method as described in claim 9, characterized in that, Also includes: Acquire historical partial discharge signal data, and determine the first fixed delay that meets the preset periodic conditions based on the historical partial discharge signal data; The signal delay enhancement action is performed based on the initial fixed delay to obtain the actual execution delay; The actual execution delay is used as a preset delay signal.

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