Insulating state on-line monitoring method of cross-linked PE cable

A cross-linked polyethylene and power cable technology, applied in the direction of measuring resistance/reactance/impedance, measuring devices, testing circuits, etc., can solve problems such as particularly serious impact, weak signal strong interference, interference or shunting

Inactive Publication Date: 2006-09-20
XI AN JIAOTONG UNIV
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  • Abstract
  • Description
  • Claims
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Problems solved by technology

There are three reasons: 1) The chemical potential Es and the sheath insulation resistance Rs drop caused by the corrosion of the cable sheath metal is an important reason that restricts most online detection methods from entering the practical stage, especially the impact on the "DC component method" is particularly serious
This is because the series equivalent branch composed of the grounding chemical potential Es of the cable shield and the sheath insulation resistance Rs is actually in parallel with the detection impedance of the on-line detection equipment, and their interference or shunt to the detected weak real signal is also very small. It is unavoidable; 2) Trace monitoring is a characteristic of insulation on-line detection, electrostatic induction is the enemy of DC micro-current detection, power frequency strong electric field and corona multi-spectrum interference will cause strong interference to all online detection weak signals; 3) Safety The problem is the primary problem that all online testing institutes must solve, and the hazards to personnel and equipment in case of cable insulation breakdown must be considered

Method used

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  • Insulating state on-line monitoring method of cross-linked PE cable
  • Insulating state on-line monitoring method of cross-linked PE cable
  • Insulating state on-line monitoring method of cross-linked PE cable

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Embodiment Construction

[0041] One of the principles on which the present invention is based is that water tree branches are the primary form of insulation aging of cross-linked polyethylene cables, and water tree branches are a phenomenon that occurs in polymer-insulated power cables under long-term operating voltages in the presence of trace moisture. A dendritic insulation aging defect. The generation and continuous growth of water tree branches under the long-term operating voltage of the cable is the main reason for shortening the insulation life of XLPE cables and finally causing electric trees at the tip of water tree branches and causing main insulation breakdown accidents. The water tree branch will produce a rectification effect under the AC voltage. The nA-level weak DC current and operation trend generated by the rectification effect in the main insulation of the cable can be detected on the cable grounding wire, and the aging status of the cable insulation water tree can be known. When t...

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Abstract

The invention discloses online monitoring method of the insulation state method for crossing polyethylene insulated power cable that adopts DC superposing method to take online testing for the three phase XLPE power cable. After gaining the parameters, GPRS would send it to host computer, which would take analysis to the data and judge the insulation state. The invention realizes unattended operation online monitoring and wireless remote controlling and measuring.

Description

technical field [0001] The invention relates to an on-line detection method and a device thereof, in particular to an on-line detection method for the insulation state of a cross-linked polyethylene (XLPE) insulated power cable. Background technique [0002] Cross-linked polyethylene (XLPE) insulated power cables are widely used in power systems due to their good electrical and thermal properties and many other advantages. Paper) The main cable varieties of high voltage cables. Relevant departments in Japan have investigated and analyzed the accident causes of 6.6kV XLPE cables put into operation from 1963 to 1979 and found that more accidents occurred in cables laid before 1970. In terms of the number of years of use, the number of cable accidents and replacements increased sharply after 8 years of operation. From the perspective of the types of accidents, water trees, natural aging, and water immersion account for 50% of the total accidents. When ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01R31/14G01R27/02G01R31/08
Inventor 郑晓泉徐阳梁红军朱义东刘斌
Owner XI AN JIAOTONG UNIV
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