What Happens If Water Enter Into Power Cable

How Water Enter Into Power Cable and Damage it?

Fig: 400kV underground power cables laid for transfer power from a power plant to grid substation.

What actually happens if water or moisture entered into the power cable?

We who are engaged with power cable management everyone very concuss to prevent enter water or moisture into cables. In the design and production line, they take some options to prevent moisture enter into cables; similarly, the cable installation and storage team also take tight action to prevent water or moisture enter into the cables. 

Cable Conductors Materials:

Widely used power cable conductors materials are Copper and Aluminum. 100% pure Copper and 99.5% or better pure Aluminum is used for better performance power cable conductor. A small amount of impurity may reduce a large percentage of conductivity. Silver is a very good conductor, but high cost and extreme softness is the obligation to use as wide scale. Compare to Copper Aluminum is inexpensive and softer.

Aluminum Uses in Power Cable:

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Many Copper conductors also use Aluminum as an armoured or metal sheath. Aluminium is very much sensitive to water in insulated power cables. So, the presence of water in Aluminum causes several problems. In Aluminum, if there is water in absence of Oxygen, chemically there will be hydrolyzing. 

Aluminium and Water Chemical Reaction:

The chemical reaction of Aluminum and water will be as follows:

2 Al + 6 H₂O   =   2Al(OH)₃ +3H₂  

So, if water entered into having Aluminum in the insulated power cable, in absence of Oxygen Aluminum and water chemically combine and produce Aluminum-Hydroxide and Hydrogen gas.

Aluminum Hydroxide:

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Aluminum Hydroxide is a white and powder type materials having a very good insulating character that degrades the conductor conductivity.

This is the theoretical and chemical reaction of water present inside the cable. Moreover, water presence in the vicinity of the cable for a long time may cause cable damage shortening the cable lifetime and unexpected breakdown may happen.