Integrated comprehensive underground cable maintenance detection method, detection system and detection instrument

Abstract

The invention belongs to the technical field of underground cable detection, and discloses an integrated comprehensive underground cable maintenance detection method, a detection system and a detection instrument. The received induction electromagnetic field signal of the cable and the magnetic field signal, the sound signal and the leakage current signal generated by the impact discharge of the cable fault point are processed, and integrated cable path detection and cable fault point detection are carried out on the processed magnetic field signal, the sound signal and the leakage current signal. Compared with a traditional path instrument and a locating instrument with a single function, the detection instrument can be applied to more application scenes; different working modes can be switched through simple operation, so that corresponding methods can be quickly switched for detection according to different detection requirements; analog signal conditioning and digital signal processing are adopted, so that the instrument has relatively strong anti-interference capability and signal processing capability; and according to the invention, the problem that a cable fault point cannot be effectively detected because an impact discharge sound signal is interfered by background noise when an acoustic-magnetic synchronization method is adopted can be solved.

Description

technical field [0001] The invention belongs to the technical field of underground cable detection, and in particular relates to an integrated underground cable maintenance detection method, detection system and detection instrument. Background technique [0002] At present, buried power cables are mostly used for laying power transmission cables in cities. Since the cables are buried underground, considering the transformation of the power grid and cable relocation, the original drawings and materials may not correctly reflect the laying path of the underground cables. Once the cables fail , if the cable path information is not clear enough and the fault finding is inaccurate, it will delay the time to repair the cable fault, causing inconvenience to people's lives and huge economic losses. [0003] Underground cable fault detection first needs to determine the type of cable fault; then roughly measure the distance to the fault point according to the type of cable fault; e...

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Problems solved by technology

[0006] (2) Audio induction method, because the amplitude of the signal received before and after the fault point does not change significantly, and this method is only suitable for a small amount of low-impedance faults accounting for 10% of the total number of cable faults, and the current application is relatively seldom

[0007] (3) The acousto-magnetic synchronization method is widely used at present and is suitable for high-resistance and flashover faults accounting for 90% of the total number of cable faults. The main factor restricting this method is that the sound signal generated by the fault point discharge is very weak and easily Aiming at this problem, the document "Research on Power Cable Fault Location Based on Acousto-Magnetic Synchronization Principle" designed a filter circuit to filter the sound signal, and selected a specific frequency sound signal through the frequency identification module. The detection effect of the method is ideal when the signal-to-noise ratio and the discharge sound signal are stable, but the discharge sound at the fault point is not a single-frequency signal, and has a wide frequency range. The frequency spectrum has a great influence. In addition, the size of the discharge sound through earphones is also an effective method to judge the distance from the fault point. Therefore, it is necessary to preserve the important spectral components of the discharge sound signal as much as possible.

[0008] (4) The step voltage method is suitable for the fault location of the insulation fault of the outer sheath of the directly buried cable. It is difficult to generate discharge sound under this fault, and the acoustic-magnetic synchronization method is not applicable

[0009] Through the above analysis, the existing problems and defects of the prior art are: (1) The detection method and implementation function are single, no measures to suppress external interference are taken, the signal processing ability is weak, and the overall efficiency is not high

[0010] (2) The application scenarios of the traditional detection method are rare; it cannot effectively solve the problem that the impact discharge sound signal is interfered by the background noise when the acousto-magnetic synchronization method is used to effectively detect the fault point of the cable

[0011] The difficulty in solving the above problems and defects is: to realize real-time detection and processing of various signals such as magnetic field, sound, and potential difference, and to display and output the processing results in real time. The conversion of corresponding functions and interactive interfaces is difficult for a single-core processor to complete in real time due to multitasking and high real-time requirements. Then, two processors are divided into upper and lower computers to decompose tasks. In order to meet the real-time performance of tasks and inter-processor The real-time transmission of data increases the difficulty of hardware design and programming; the on-site environment of cable detection is complex and diverse, and there are many interferences, and the detection equipment needs to have strong anti-interference ability and high reliability; The energy of the sound signal itself is relatively weak, and then propagated through the soil and other media to cause a certain attenuation, making the signal received by the microphone very weak, coupled with the interference of the surrounding background noise, which increases the difficulty of detecting the sound signal of the impact discharge, which in turn affects the Fault point detection accuracy

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