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Cable aging estimation method combining step-by-step withstand voltage method and isothermal relaxation current method

A technology of isothermal relaxation current and aging evaluation, applied in the direction of testing dielectric strength, etc., can solve the problems of accumulation effect of insulation, shorten the service life of cables, difficult to find weak links in insulation, etc., and achieve the effect of avoiding one-sided reflection.

Inactive Publication Date: 2015-06-24
SOUTH CHINA UNIV OF TECH
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  • Application Information

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Problems solved by technology

The former mainly depends on the dielectric constant of each medium, while the latter mainly depends on the resistivity of the material. The difference in principle between the two makes it difficult to find the weak link of insulation under AC voltage in the DC voltage test.
[0004] In addition, the DC withstand voltage test has a cumulative effect on the insulation, which will accelerate the aging of the cable and shorten the service life of the cable
Therefore, XLPE cables do not use the DC withstand voltage test

Method used

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  • Cable aging estimation method combining step-by-step withstand voltage method and isothermal relaxation current method
  • Cable aging estimation method combining step-by-step withstand voltage method and isothermal relaxation current method
  • Cable aging estimation method combining step-by-step withstand voltage method and isothermal relaxation current method

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Embodiment

[0041] In this embodiment, a cable aging evaluation method combined with a stepwise withstand voltage method and an isothermal relaxation current method disclosed in the present invention is used to perform cable aging evaluation on cable samples.

[0042] 1. Selection of cable samples

[0043] This evaluation test selects 110kV XLPE cables, the specific models are as follows:

[0044] 1) Put into use in 1985, 2 cables produced by Sumitomo, Japan. No. S1, S2.

[0045] 2) Put into use in 1987, 2 cables produced by Furukawa, Japan. Number F1, F2.

[0046] 3) Put into use in 1996, 2 cables produced by Sumitomo, Japan. No. S3, S4.

[0047] The cross-sections of the above six cable samples are all 400mm2, and the length of each cable is about 20m.

[0048] 2. Partial discharge test

[0049]Sampling for partial discharge test, according to the measured apparent discharge and GB / T 11017.2-2002 (national standard (GB) GB / T11017.1-2002 rated voltage 110kV XLPE insulated power ca...

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Abstract

The invention discloses a cable aging estimation method combining a step-by-step withstand voltage method and an isothermal relaxation current method. The cable aging estimation method includes the following steps of step-by-step withstand voltage method testing and isothermal relaxation current method testing. According to the cable aging estimation method, on one hand, a result obtained through the isothermal relaxation current method is used as a tendency judgment and used for judging a rough cable aging degree, and on the other hand, a result obtained through the withstand voltage method is used as a concrete judgment, and then the remaining service life of a cable can be inferred. In other words, the result obtained through the isothermal relaxation current method is the tendency judgment, the result obtained through the withstand voltage method is the concrete judgment, and hereby the cable aging situation can be estimated by combining a destructive test and a nondestructive test to determine whether the cable needs to be replaced or not. Accordingly, one-sided reflection of a single method on an estimation result is avoided, the result can be higher in reference value, and the cable aging estimation method can have guidance significance on power grid transformation and operation, maintenance and detection of the cable.

Description

technical field [0001] The invention relates to the technical field of testing the insulation performance of cross-linked polyethylene cables, in particular to a method for quickly testing the insulation performance of cross-linked polyethylene cables combined with a step-by-step withstand voltage method and an isothermal relaxation current method. Background technique [0002] Since the 1980s, cable technology at home and abroad has developed rapidly, and traditional oil-filled cables have been gradually replaced by XLPE cables manufactured by three-layer co-extrusion production technology. Compared with the former, the latter has excellent properties such as no oil supply, fire prevention, simple installation and maintenance, and good mechanical and electrical performance, and its application range is gradually expanding. Taking China as an example, XLPE cables are widely used in big cities such as Shanghai, Beijing, and Guangzhou. It is of great significance to fully und...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01R31/12
Inventor 刘刚金尚儿
Owner SOUTH CHINA UNIV OF TECH
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