66Kv vs 132Kv subsea cable what are pros and cons

[escapizm]

Hi All

Question from a simple mechanical/hydraulic/Subsea engineer...

In a windfarm what are the pros/cons of switching from a 66Kv copper subsea cable to a 132Kv cable?

Does the cable physical CSA / diameter change or is it just an increase in power for the same properties? Obviously, all the associated switchgear etc will be more expensive I presume for 132Kv?

Any link to "understating electric power for numptys" appreciated.

THanks

 

[bacon4life]

The cable has many layers. The XLPE insulation doubles in thickness, but the other layers like the conductor, shield, and armor would not necessarily have a large increase. Typical cable parameters are available at [URL unfurl="true"]https://www.southwire.com/wire-cable/high-voltage-underground-69kv-and-up-/c/c-high-voltage-underground[/url].

Capacitive charging current increases with voltage, and is often the limiting parameter for long undersea cables.

 

[escapizm]

Thanks bacon4life!

As a simple man, I try to consider this in terms im familiar with, like hydraulics...

So the voltage increase is like increasing the pressure in a pipe, the wall thickness (insulation) needs to be thicker.

The flow or current remains the same so the diameter need not increase.

Tks

escapizm

 

[Gr8blu]

There are two things that can happen with the cable selection when increasing the voltage. One is - as bacon4life indicated - a simple doubling of the external "jacket" to accommodate the higher voltage ... in mechanical terms, doubling the pipe wall thickness to withstand the additional pressure. This allows MUCH more current (or liquid, in the case of hydraulics) to flow because the INSIDE of the pipe has remained the same size.

If you don't need more flow, though, you can do it another way. You can double the insulation (wall) thickness, but instead of adding to the exterior surface, you can add to the interior surface. Of course, when you do this the diameter of the conductor (or pipe) must also become smaller - restricting flow.

If we keep the conductor (pipe ID) the same, we get more power (fluid) flow at the higher voltage (pressure).
If we reduce the conductor (pipe ID), we get the same power (fluid) flow at the higher voltage (pressure).


Converting energy to motion for more than half a century

 

[escapizm]

Great thanks Gr8blu