Underground Transmission in Europe

[harmonicoscillation]

I was at a conference with FERC Chairman Pat Wood yesterday regarding the technical feasibility of high voltage UG transmission and one guy made a number of claims regarding the extent of underground transmission in Europe. It left me wondering about the veracity of his claims, as I keep hearing a lot of hearsay on this subject. Does anyone here have personal experience with underground transmission in Europe, common voltage levels, standard construction methodology and cable design, repair techniques, and how they address charging capacitance, harmonics and other related issues? Thanks in advance.

 

[busbar]

 
{Forwarded on behalf of C-H Gustafsson..}

I had a peek at Eng-tips and found an unanswered posting about "Underground Transmission in Europe". (

http://www.eng-tips.com/viewthread.cfm?qid=105554)

Could you kindly forward this the forum:

Whilst I myself know next to nothing about this subject, perhaps the sources below can shed some light on the matter:

http://www.verbund.at/en/apg/netzausbau/netzsituation/kabel.htm

http://www.rte-france.com/htm/an/envirnmt/envirnmt_milieu_enfouiligne.htm

http://www.nationalgrid.com/uk/library/brochures/overhead_underground/mn_introduction.html

http://www.etso-net.org/upload/documents/ETSO POSITION ON UNDERGROUND CABLES.pdf

http://www.svk.se/upload/3189/Natkarta_eng.pdf

According to their catalogue, there is a CIGRE (International Council on Large Electric Systems) publication on this subject:

"Comparison of high voltage overhead lines and underground cables. Report and Guidelines.

A reference document when overhead and underground options for transmission circuits are being compared and when possible routes are being negotiated with the relevant authorities. The comparison is made under the following headings: system planning and operation, environmental, technical, cost and future perspectives. CE/SC21 JWG/GTM21/22.01, 1997, 68 pp. Ref. No. 110"

Thanks in advance

Clas-Henrik Gustafsson

 

[rsherry]

Do you mean to make a distinction by using the phrase "high voltage" (HV)? In power system terminology transmission is usually referred to as at EHV rather than HV.
A large proportion of urban load is fed from EHV and HV cable networks into cities.. so if you measure the load fed by 'transmission' cable it is huge.. but these cables are short.
For bulk transmission, only a very small percentage is underground. It is mostly DC cables for under-sea connection (eg the 2000MW France-England link and the links to Sweden and Norway). The longest AC transmission link is the Spanish one which is about 20km long i think.

Google for UCPTE to find details of the european grid.

 

[Shavner]

I've had some experience in eastern Europe, Lithuania, Estonia, Latvia and down in Moldova and yes the "HV" is underground most common is 11kv distribution to largeer sites and also the usage voltage (380/220) in lithuania is loop fed thru various transfer switches in different buildings with little to no markings (OSHA hasent made it into the eastern block countries yet) but from what I've seen the power is very dirty, with all kinds of harmonics, drops and dips to the point that the power is not very reliable, however in thier defense the ability to have power is a major plus even if it isn't very clean. So if you are connecting to this grid and need reliable power I'd suggest voltage regulators, isolation transformers and cap banks, and if it is necessary UPS or Generator backup.