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Ah - Strand Fill is that process for protecting aged XLPE cables by filling the strands with silicon oil - right? I'm not talking about that. This is where you buy new cables with polyethylene tapes or yarns impregnated with swellable powders, wrapped around each layer of conductors. It's...

I'm talking about using powder filled tapes or yarns to fill the gaps between strands - I think strand fill is an example of the technology. Geca tapes is another company that supplies the water blocking products. I discussed this with cable accessory suppliers prior to writing the spec and...

Anyone have any comments on water blocking conductors on HV cables? In particular, does using non conducting vs semi conducting tapes make any difference? We're looking for cables that we can joint or terminate without the need to open strands and pull out the tapes first. thanks

Thanks David - that reference and your comments were very helpful

Where is a good place to look for standard equations on transmisison line regulation, line losses, and also, information on use of transposition structures to manage the above? thanks

Yep we're all talking about the same type of cable - PILC. I know it's normally only screened/shielded at 15kV or above, and belted below that, but screens permit a higher rating, which we have been using. We have had a number of failures in this cable due to either damage during installation...

Has anyone had experience with paper insulated cables at 11kV failing due to damage of the metalised paper screen? I know screening isn't mandatory for 11kV cables, but if you have it, have you had any experience of faults arising from imperfections or tears in the screen? thanks

Depending on the environment in which the cables are being laid, it could also be to reduce emf levels which create interference with some electrical equipment in the vicinity, or make local residents angry and worried about health effects. The preferred configuration to reduce emf is trefoil...

Couple of comments. You've got some pretty good comments up there already. We use a shield wire on all our 132kV lines for the added reliability. There was considerable debate over the added cost when we first started doing these voltages in about the 1960s, but it proved itself - lightning...

Has anyone had some experience with using DTS systems to monitor power cables, particularly at higher voltages? I want to find some companies that supply the equipment, apart from SENSA/York in the UK. I have found a couple of others (Hitele, Optech) but I want to find out if there are other...

There is another issue here which I have been dealing with recently. Putting a relatively short section of cable (especially such a critical part of a network as a 230kV cable) into an overhead line really gives the utility the worst of both worlds. They have the long repair times of an...

I would have thought the biggest problem facing utility generators is simply the financial burden. They base their charges on an assumed amount of downtime/low load. If wind etc are to be given preference as a source of generation, then the utility still has the same plant on hand, but less...

Sorry I don't know of any papers on the subject but do have some experience with it. With the long dry period here, recent slight rains brought on quite a spate of pole top fires. They almost always occur at the bolt securing the insulator to the crossarm or the king bolt securing the crossarm...

ASCE publish a guideline on it but unfortunately I don't remember which one- could be ASCE 42? Sorry.

Depends what country/state you are in. The minimum clearances are usually specified by your national standards authority or electricity regulator. In Australia, our minimum clearnce to ground is 6.7 - 7.6 metres depending on ground type - trifficable or not. Tower lines are usually quite a bit...

A common reason for preferring single phase cables in ductlines is simply that some older ducts are too small and the multicore won't fit.

Thanks cuky and jbartos. Jbartos - we actually use dc tests for proving joints and repairs on higher voltage cables (33kV and above). Impulse tests we really only use for acceptance testing. We are looking for criteria we can use to prioritise for replacement of a large network of power cables...

I'm still getting up to speed on these, but we are getting some XLPE and some EPR cable for 11kV. The compact EPR is smaller than the equivalent XLPE, but part of that (and the reduced cost) is coming from the elimination of water blocking tapes we specified on the XLPE. We still can't really...

Corrugated aluminium sheath is quite common up to 132kV on oil filled cables (low pressure oil). It provides a strong moisture barrier which resists internal pressure well, and provides a good earth current return path. As above, it doesn't do the shielding job well, but it's possible to have a...

I'd appreciate any ideas on places to look for info on determining the condition of paper lead power cables (33kV mostly) in aged cables. I'm trying to develop some guidelines for determining when a cable is approaching the end of its economic life, and how to prioritise replacement programmes...