From which grid is the Channel Tunnel electrified?

[Dima]

As Britain and France belong to different electrical grids that are not synced with each other, how does it impact the electrification of the Channel Tunnel?

As I understand it, the OHLE uses AC provided by the national grid, so it’s in sync with the grid, how does it work when a line goes from one grid area to another? Are parts of line electrified from different grids with a neutral section separating them? Given the length of the Eurostar train, the neutral section would need to be rather long… Or is there something different?

Thanks!

 

[GC class B1]

I think I am correct that the whole of the channel tunnel is fed from France. I have visited the terminal in Folkestone and all the cars are left hand drive and the time is French time.

 

[martin2345uk]

As Britain and France belong to different electrical grids that are not synced with each other, how does it impact the electrification of the Channel Tunnel?

As I understand it, the OHLE uses AC provided by the national grid, so it’s in sync with the grid, how does it work when a line goes from one grid area to another? Are parts of line electrified from different grids with a neutral section separating them? Given the length of the Eurostar train, the neutral section would need to be rather long… Or is there something different?

Thanks!

Neutral sections do not need to be as long as the trains using them.

 

[edwin_m]

I've an idea it can be fed from either end, but I'm not certain of that. It certainly has control rooms both ends, as these were mentioned on a TV programme I saw recently and I think they visited the offline one.

There are probably neutral sections, but as mentioned they don't relate to the train length. Any train with multiple pantographs raised at the same time has no electrical connection between them, they just power different sets of motors.

 

[Dima]

I think I am correct that the whole of the channel tunnel is fed from France. I have visited the terminal in Folkestone and all the cars are left hand drive and the time is French time.

Sounds plausible, given that initially the trains would switch to third rail DC in England.

Anyway, I just realised the arrangement on the boundaries between the sections fed by different grids shouldn’t be too different to that between the sections fed by different phases of the same grid, and there are plenty of them.

There are probably neutral sections, but as mentioned they don't relate to the train length. Any train with multiple pantographs raised at the same time has no electrical connection between them, they just power different sets of motors.

What happens if one pantograph gets broken? The half of motors will get out of action? Is there a way to energise them from the remaining pantograph? If so, I would imagine that there’s some circuit breaker between the parts of the train which is normally open? How are the auxiliary systems on the train fed?

 

[MarcVD]

There are two redundant substations, one at each end, acting as a backup for each other, and regularly switched over. Look in Google Maps, they're both very visible.

As Britain and France belong to different electrical grids that are not synced with each other, how does it impact the electrification of the Channel Tunnel?

Are you sure the two networks are not in sync ? There are 3 undersea power interconnects between France and Great Britain. Are they all DC then ?

 

[swt_passenger]

Are you sure the two networks are not in sync ? There are 3 undersea power interconnects between France and Great Britain. Are they all DC then ?

Yes, the channel interconnectors are DC.

 

[Class172]

Are you sure the two networks are not in sync ? There are 3 undersea power interconnects between France and Great Britain. Are they all DC then ?

Yes, the channel interconnectors are DC.

Indeed, and I believe all the international interconnectors run using high-voltage DC. You can see them on this infrastructure map, where HVHC is an indigo colour.

 

[Dima]

There are two redundant substations, one at each end, acting as a backup for each other, and regularly switched over. Look in Google Maps, they're both very visible.

Just found a confirmation of this on the Getlink’s website:

Electrical power supplying the tunnels, drainage pumps, lighting and the trains, is provided by substations on each side of the Channel. In the event of loss of power from one side, the entire system can be supplied from the other side

Are you sure the two networks are not in sync ? There are 3 undersea power interconnects between France and Great Britain. Are they all DC then ?

Yes, France is party of the synchronous grid of continental Europe, and Great Britain has its own grid, connected to the neighbours via DC links.

 

[edwin_m]

What happens if one pantograph gets broken? The half of motors will get out of action? Is there a way to energise them from the remaining pantograph? If so, I would imagine that there’s some circuit breaker between the parts of the train which is normally open? How are the auxiliary systems on the train fed?

It varies with different train types - not sure what happens with Eurostar. The 700s have two separate traction systems each fed by one pantograph but the auxiliaries are cross-fed at a lower voltage. If one pan fails, half power is enough to get back to the depot. Other trains may have various cross-feeding arrangements or duplicated pantographs electrically connected, but if more than one pantograph is raised, they are never connected to each other electrically.

 

[AM9]

It varies with different train types - not sure what happens with Eurostar. The 700s have two separate traction systems each fed by one pantograph but the auxiliaries are cross-fed at a lower voltage. If one pan fails, half power is enough to get back to the depot. Other trains may have various cross-feeding arrangements or duplicated pantographs electrically connected, but if more than one pantograph is raised, they are never connected to each other electrically.

The example of the class 700s was exactly what I was going to refer to. The class 374 (e320) EMUs have 16MW of installed traction so a failure of the system in one half would be adequate to recover the train at reasonable speeds and up the pretty steep inclines on the route.

 

[Dima]

Makes sense, thank you!

 

[LNW-GW Joint]

There are 3 undersea power interconnects between France and Great Britain. Are they all DC then ?

One of which ("Eleclink") runs through the tunnel itself and earns Getlink money.