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Power cable defect positioning and diagnostic method based on echo loss spectrum method

A return loss and power cable technology, which is applied in the field of precise positioning and diagnosis of local defects in power cables, can solve the problems that the severity of defects cannot be evaluated, the high-frequency signal components are few, and the recognition rate is not very high, etc., and achieve low cost and easy operation. Convenience and sensitivity-enhancing effects

Inactive Publication Date: 2019-10-11
STATE GRID CHONGQING ELECTRIC POWER
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, because the high-frequency signal components in the pulse are relatively small in this method, the recognition rate for relatively weak defects and defects near the head end is not very high, and at the same time, the severity of defects cannot be evaluated.

Method used

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  • Power cable defect positioning and diagnostic method based on echo loss spectrum method
  • Power cable defect positioning and diagnostic method based on echo loss spectrum method
  • Power cable defect positioning and diagnostic method based on echo loss spectrum method

Examples

Experimental program
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Embodiment 1

[0033] In this embodiment, the 500m long YJLV223×150 type 8.7 / 15kV XLPE power cable is taken as the research object, and the fault defect location diagnosis is carried out. Make intermediate joints at 100m and 250m of the cable, and artificially make defects at the joint position of 100m. The type of defect is that the copper connecting pipe is not polished. The specific schematic diagram of the test sample of the power cable to be tested is as follows figure 2 shown.

[0034] This embodiment locates and diagnoses the above-mentioned power cable defects, such as figure 1 shown, including the following steps:

[0035]S1 measurement data: transmit frequency sweep pulse V to the power cable under test i , measuring the reflected signal V r .

[0036] By sending sweeping pulses to the head end of the power cable to be tested, the incident signal is denoted as V i , measuring the reflected signal V reflected from the cable r , the frequency of the injected sweep pulse is f. ...

Embodiment 2

[0051] In this embodiment, a 100-m-long YJLV22×240 type 26 / 35kV XLPE power cable is taken as the research object to perform fault location diagnosis. Partial moisture treatment is carried out at 50m in the middle of the cable. The moisture treatment process is: inject 3ml of water into the outer sheath of the cable where the cable needs to be damp, through a syringe to simulate the local moisture defect of the cable. The schematic diagram of the specific test sample of the power cable to be tested is as follows: Figure 4 shown.

[0052] This embodiment locates and diagnoses the above-mentioned power cable defects, such as figure 1 shown, including the following steps:

[0053] S1 measurement data: transmit frequency sweep pulse V to the power cable under test i , measuring the reflected signal V r .

[0054] By sending sweeping pulses to the head end of the power cable to be tested, the incident signal is denoted as V i , measuring the reflected signal V reflected from ...

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Abstract

The invention discloses a power cable defect positioning and diagnostic method based on an echo loss spectrum method. An echo loss spectrum is acquired through transmitting a sweep frequency pulse transmitted to a power cable and a reflected signal reflected back; the echo loss spectrum is subjected to windowing treatment, fast Fourier transform and other treatments and then mapped to a distance diagnostic spectrum; and positioning of a power cable defect and diagnosis on the severity degree of the defect can be synchronously achieved by using a distortion point position and the size of a wavepeak amplitude in the distance diagnostic spectrum.

Description

technical field [0001] The invention belongs to the field of electric technology, and relates to a defect diagnosis technology of a power cable, in particular to a method for accurately locating and diagnosing a local defect of a power cable. Background technique [0002] With the continuous expansion of urbanization and the vigorous development of industry, 10kV power cables are widely used. Cross-linked polyethylene (XLPE) power cables are widely used in urban power grids in my country because of their good electrical and mechanical properties. However, due to the immaturity of the early cable technology and the harsh construction environment, the cable often has local defects such as insulation deformation, loose copper tape, and copper shielding grounding due to moisture, extrusion, excessive bending, and damage to the outer sheath. The cables put into operation will also cause local thermal aging, radiation aging, mechanical vibration, etc. due to local heat sources, w...

Claims

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Application Information

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IPC IPC(8): G01R31/08G01R31/11G01R31/02G01R31/12
CPCG01R31/083G01R31/11G01R31/1272G01R31/58G01R31/50
Inventor 马骁余华兴马弢顾博张午阳黄会贤周勇邵愚刘云龙
Owner STATE GRID CHONGQING ELECTRIC POWER
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