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Test method for unshaded corona onset voltage of medium-voltage crosslinked polyethylene cable

A technology of cross-linked polyethylene and corona inception voltage, which is applied in the direction of testing dielectric strength, etc., to improve the corona inception voltage and avoid huge losses

Active Publication Date: 2014-12-24
甘肃省电力公司刘家峡水电厂 +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, no matter at home and abroad, there is currently no early-stage search method for the internal defects of newly produced cable heads and cable heads in use.

Method used

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  • Test method for unshaded corona onset voltage of medium-voltage crosslinked polyethylene cable

Examples

Experimental program
Comparison scheme
Effect test

experiment example 1

[0024] Experimental example 1. Unshielded corona inception voltage test of medium voltage XLPE cable with stress tube

[0025] Choose YJV 22 -3×35mm 2 8.7 / 15kV XLPE cables are used as test items. Firstly, the cable head is made by using the current stress tube technology. The cable head of the stress tube cuts a 3×4mm square hole on the stress tube at the cutout of the semi-conductive layer, but as the sheath tube of the auxiliary insulating layer or the weather resistance The tube is not installed for the convenience of observing the corona during the test. The test site must be selected in a dark room without any light source.

[0026] The purpose of the test: to measure and determine the corona inception voltage value of the cable terminal made by using the stress tube process method.

[0027] according to figure 1 As shown, ground the ground wire 5 of the cable shielding layer, connect the terminal of the cable lead wire 1 to the high voltage test connection wire 2, c...

experiment example 2

[0030] Experimental example 2. Unshielded corona inception voltage test of a medium voltage XLPE cable wrapped around a stress cone

[0031] This test method is the same as that of Experimental Example 1 above, and compared with Experimental Example 1. In order to avoid the quality deviation of different cables, especially the difference in the thickness and material of the cable insulation layer, the deviation of the experimental results is caused. The same 3.9-meter-long YJV with the same specification was selected for the test 22 -3×35mm 2 8.7 / 15kV XLPE cables are used as test items. At the other end of the same-phase cable that has been fitted with a stress tube in Experimental Example 1, a medium-voltage XLPE insulated stress-cone cable terminal was fabricated using the wrapping stress-cone process, and a comparison test of the cable head’s corona inception voltage was carried out. The patent application for the medium-voltage cross-linked polyethylene insulated stress...

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Abstract

The invention relates to a test method for an unshaded corona onset voltage of a medium-voltage crosslinked polyethylene cable. The test method is characterized by comprising the following steps: taking a medium-voltage crosslinked polyethylene unshaded cable head without an insulating jacket tube as a tested main body; in a darkroom, using a power frequency alternating current voltage-resisting device frequently used in the present power system as a test device; performing an alternating current voltage-resisting test on the tested cable head; and in the alternating current voltage-resisting test, observing and recording a test voltage value at the corona starting moment of a cut port of a semi-conductive layer of the cable head, thereby obtaining a corona onset voltage value of the cable. According to the test method provided by the invention, the internal defect and insulation detect of the cable head can be detected and treated in advance; especially, before the cable is used, the insulation detect of the new medium-voltage crosslinked polyethylene cable head is detected as early as possible; the cable accidents are eliminated before the running of the cable; the work reliability of the medium-voltage crosslinked polyethylene cable is increased, so that the medium-voltage crosslinked polyethylene cable accidents are reduced or eliminated; and the power supply reliability of the power system and the power-utilization reliability of the cable users are increased.

Description

technical field [0001] The invention belongs to the technical field of quality inspection of insulation structures of cable terminal heads, and in particular relates to a test method for unshielded corona inception voltage of medium-voltage cross-linked polyethylene cables. Background technique [0002] The power system refers to the voltage level of 6 ~ 35kV as medium voltage, and the medium voltage power grid refers to the power grid or power system with a voltage level of 6 ~ 35kV. [0003] Medium voltage cross-linked polyethylene (XLPE) power cables are widely used to transmit electric energy both at home and abroad. When using cross-linked polyethylene cables, both ends of the cable must be made of cable terminals, which are called cable terminals in the industry; when using cables to transmit power over long distances, it is necessary to connect two or more cables, and connect adjacent To connect two cables, it is necessary to make a cable intermediate joint. In this...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G01R31/12
Inventor 王恩选段忠义沈利平付廷勤曾需要刘发展朱国海刘伟容立辉
Owner 甘肃省电力公司刘家峡水电厂
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