How much DC current flows through undersea cables?

[JerryMungo]

.

 

[Moosedrool]

As the title asks... Anyone know off hand?

Depending on how long and how many repeaters there are I guess. The only article I got just says up to 10000 Volts. Current will depend on the repeater requirements.

 

[eddief1]

This is a very interesting topic, not often discussed how they power the repeaters

 

[Moosedrool]

We should ask this shark.

 

[P924]

We should ask this shark.


View attachment 1035166

I have heard about Wireshark.

 

[Jet-Fighter7700]

This is a very interesting topic, not often discussed how they power the repeaters

whats more interesting is how they get them there,
buried under the seafloor and invisible, until a Ship drops anchor and damages a cable.

 

[Creag]

We should ask this shark.


View attachment 1035166

Shocking!

 

[Dairyfarmer]

The only article I got just says up to 10000 Volts. Current will depend on the repeater requirements.

Volts and Current or not the same thing.

Voltage is the cause and current is its effect. Voltage can exist without current.
Current is the effect (voltage being the cause). Current cannot flow without Voltage.

See here for AC and DC voltage

Submarine power cable - Wikipedia

en.wikipedia.org

 

[Voicy]

Uhhh...aren't undersea cables optic fibre?

The repeaters just receive the diminishing light beams, converts them and sends out new light beams "repeating" the same signals as the diminishing ones.

DC volt drops are noticeable over 50meters, so I doubt they'd use that for transmission of signals. Even RS485 is capped at 500m.

 

[Dairyfarmer]

@The_Hobbit
Quick answer is:
DC - between 200 and 600 kV
AC - 30 and 525 kV

 

[Moosedrool]

Volts and Current or not the same thing.

See here for AC and DC voltage

Submarine power cable - Wikipedia

en.wikipedia.org

lol yes, hence: “Current is depended on repeater requirements.” Each oceanic cable will have a different resistance.

 

[Moosedrool]

Uhhh...aren't undersea cables optic fibre?

The repeaters just receive the diminishing light beams, converts them and sends out new light beams "repeating" the same signals as the diminishing ones.

DC volt drops are noticeable over 50meters, so I doubt they'd use that for transmission of signals. Even RS485 is capped at 500m.

And where do you think the repeaters gets their power?

Edit: Anyway I found the wiki.

Submarine communications cable - Wikipedia

en.wikipedia.org

Repeaters are powered by a constant direct current passed down the conductor near the centre of the cable, so all repeaters in a cable are in series. Power feed equipment is installed at the terminal stations. Typically both ends share the current generation with one end providing a positive voltage and the other a negative voltage. A virtual earth point exists roughly halfway along the cable under normal operation. The amplifiers or repeaters derive their power from the potential difference across them. The voltage passed down the cable is often anywhere from 3000 to 15,000VDC at a current of up to 1,100mA, with the current increasing with decreasing voltage; the current at 10,000VDC is up to 1,650mA. Hence the total amount of power sent into the cable is often up to 16.5kW.[34][35]

 

[starmage]

There are also submarine power cables (not optic fibre but power transmission)
https://en.wikipedia.org/wiki/Submarine_power_cable -- some carry as much 2200MW of power

 

[Voicy]

And where do you think the repeaters gets their power?

Edit: Anyway I found the wiki.

Submarine communications cable - Wikipedia

en.wikipedia.org

Ugh. Of course. Sorry, don't mind me - I have the dumb.

In my mind I was picturing land based relay stations.