Elecsun,
You can use IEC60502 but it's a bit of a blunt instrument, it is a document written by manufacturers and users from around the world and thus in trying to cover such a diverse range ends up as the lowest common denominator of them all.
The specification does not, for instance...
eejacky,
Oil filled cables at 132kV are paper insulated. During routine factory testing, following manufacture, Low Pressure Oil Filled (LPOF) cables are tested using ac. This requires some sizeable transformers. The ac test is used both as a withstand test and to establish the dielectric loss...
hmchi,
I was really refering to large transmission cables.
For a quick comparison:
66kV cable 120sqmm Cu Pb Paper 3 core in air rating 294A
66kV cable 120sqmm Cu Pb Paper 1 core in air rating 483A
If single core cables are installed in ducts (raceway) and there is a cable fault in the duct...
Both single and three core cables are installed in the Uk and the preferance varies between utilities.
The days of paper cables below 132kV are just about dead and the lower the voltage the colder the corpse.
Looking at cost first, three core paper cables were cheaper than three single core...
duh,
The cable construction sounds like a 138kV HPPT system. The cables are normally wrapped with a skid wire (I think you called this a concentric neutral) which aids cable installation. There is only one cable manufacturer in North America for this cable, Okonite. They supply cable to...
Foudrette,
IEC60287 considers that all the heat generated by cables below ground escapes from the earth's surface into the atmosphere and that for continuous ratings that the ground has no thermal capacity.
In the case of deep cables you must consider the thermal capacity of the soil. This is...
vladanc,
You could try thermocouples. If they are to be buried then you need thermocouples suitable for buriel, these normally have a metallic sleeve. There are a number of companies that can supply these.
The thermocouples can be produced in significant lengths however it is probable that you...
144x,
Cable defects that could "pass" routine test...
Conductor water blocking missing or inadequate
Conductor screening tapes incorrect size or type
Conductors screening material fall-in into conductor
Screening material too thin or missing
Conductor screen not bonded or marginal...
144x,
As ausphil points out, once the cable cores are laid up into a three core construction you have a different cable. The points he makes on cable bending are also valid. Another area that will be different will be radial and longitudinal water blocking on XLPE cables over the core.
If the...
With regard to XLPE I would suggest you look at the following:
1. The effect on cable AC resistance and ampacity.
2. The high level insulation stress of 230kV cable required that will fit in the pipe you describe.
3. The stress on the insulation shield and its effect on the accessories.
4...
When considering the minimum distance between cables the following is important:
Maintaining the cable ratings (ampacity): If the cables are buried then this is normally a thermal consideration. The cables being kept adequately separated to allow heat to flow away from the cables.
Mutual...
There are suppliers of subsea cable in Japan a couple are:
JPower (formerly Sumitomo and Hitachi who merged) & Showa.
You say that you have contacted European suppliers, does this include the smaller outfits like AEI Cables in the UK.
If you need any more let me know.
www.cableconsulting.net
The use of a cable shields is dependant upon the electrical stress of the cable and whether or not any air gaps will discharge (spark).
I have extracted the following from the "Electric Cables Handbook" which covers the subject. Note: screens [UK] = shields [US].
“At 6kV and above...
At high voltages, phase to phase line voltages are quoted for single core cables as at these voltages the cables are almost always used in three phase systems (one exception being railways).
A 345kV cable is the accepted way of describing a screened cable working on a 345kV LINE voltage...
6/10(12)kV
6kV = phase to earth voltage
10kV = Phase to phase (line voltage)
12kV = Um maximum line voltage
This notation applies to single core or 3 core cables.
www.cableconsulting.net
