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High voltage cable product water causes and countermeasures!

Release time:

2021-02-01

After the cable water, under the action of electric field, the phenomenon of water tree aging will occur, and finally lead to cable breakdown. A water tree is a collection of water-filled voids ranging in diameter from 0.1m to a few microns. The starting point of water tree is the local high electric field formed by the impurities, pores in insulation and the non-uniform joint surface between insulation and the inner and outer semi-conductive layers. The development process of water tree is generally more than 8 years, the higher the humidity, temperature and voltage, the more ions contained in water, the faster the development of water tree.

Water intake cause

Storage: The newly bought tube cable is sealed with a plastic sealing sleeve at both ends, but after a section is used, the rest is wrapped in plastic paper and tied with a rope outside, the sealing is not good, and the water vapor will penetrate into the cable after a long time.

When laying cables: when laying cables, the cable head wrapped in plastic paper is sometimes immersed in water, so that water enters the cable; Rupture of the outer sheath sometimes occurs during traction and threading.

After laying: the cable head is not made in time, so that the unsealed cable port is exposed to the air for a long time, or even immersed in water, so that a large amount of water vapor enters the cable.

When the cable head is made (including the terminal head and the middle joint), the cable end sometimes slips into the cable well with water due to the carelessness of the production personnel.

Cable operation: During cable operation, when the breakdown of the intermediate joint occurs, the water in the cable well will enter the cable along the gap; In construction sites, external forces cause cable damage or breakdown, and cable water will also occur.