Small 11Kv cable fire London...

[UKMeterman]

There seems to be a small cable fire in London, has affected key parts of the MV network BBC Local Live: Updates from London on Wednesday 1 April 2015 - BBC News

 

[Fin170]

If only the housing of the joint was metal....

 

[Darkwood]

If only the gas line wasn't run so close!

 

[pennychew]

Has anybody seen Doody Toody today?

 

[davesparks]

There can be only one possible cause for this......

Plumbers!

 

[tazz]

There can be only one possible cause for this......

Plumbers!

No it UKESrail (aka Essex again)........

 

[Knobhead]

He'll have been at a loose end in the afternoon

 

[sammyshooter]

Still going guys:

http://www.bbc.co.uk/news/uk-england-london-32157618

There have been surges all over central London, one knocked the till out in nandos when I was getting my tea last night, I was livid!

 

[Gardner]

I must ask, how are the 11kv MV networks earthed? Anyone know?

 

[Engineer54]

The same as LV networks, via earth electrodes....

 

[UKMeterman]

True, but there is often a neutral earthing resistor or similar at the star point of the upstream transformer.

 

[PEG]

...Watched the inferno on TV...looked a lot more troublesome than a standard PFC test...

 

[Engineer54]

True, but there is often a neutral earthing resistor or similar at the star point of the upstream transformer.

How far upstream are you talking about??

 

[Gardner]

The same as LV networks, via earth electrodes....

TT for MV? I mean the neutral point of the supply transformer. A high resistance or Peterson earthed neutral point will drastically limit fault current greatly reducing the incident energy at a fault. Solid grounding is something I would avoid in MV, even though the US does it like crazy because every other MV-LV transformer is wye-wye.

 

[Engineer54]

As far as i'm aware, all of the local MV/LV distribution network TX's are Dyn 11 (delta/wye). N-E Resistors would only be used where it is requirement to limit the fault current on the LV side. Earthing electrodes for MV and LV systems are generally separated at TX locations unless the Ra value of the electrode systems are of a suitably low value (under 1 ohm).


I don't consider MV/MV TX's as being particularly part of a local network distribution system, although in Central and the City of London the networks have been reinforced and evolved many times often in not exactly the best way, so it wouldn't surprise me at all that N-E resistors have been used quite extensively.