Single or Multicore
Single or Multicore
(OP)
Dear All
a fellow engineer and i had a long arguement about what type of mv cable to use for transformer connections,i.e. from traqnsformer to transformer or transformer to panel.
i argued that multicore cables can be used up to a feasable size, yet he argued the only single core cables can be used in transformer connections.
so what do you think?
a fellow engineer and i had a long arguement about what type of mv cable to use for transformer connections,i.e. from traqnsformer to transformer or transformer to panel.
i argued that multicore cables can be used up to a feasable size, yet he argued the only single core cables can be used in transformer connections.
so what do you think?






RE: Single or Multicore
RE: Single or Multicore
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: Single or Multicore
RE: Single or Multicore
There are some advantages of three-phase cable:
Less reactance –important if a voltage drop is involved-usually does not.
No shield induced voltage built-up –since the 3 phase shields are in contact and transposed [one may ground both ends without derating].
There are some disadvantages:
-the cable is heavy and more rigid and it could be hard to pull it -through ducts, mainly.
-the terminating are more complicated [ a little] for rated voltages above 15 kV.
RE: Single or Multicore
This would be for transformers in the 1000KVA range. Primary voltage from 4160 Volts to 25,000 Volts, secondary voltages 480V, 600V or 4160V.
parallel multi-core cables may be used for the secondary. Larger transformers may have bus duct Flexi-bus or Husky-Bus on the secondary.
This seems to be an engineering standard in a particular industry in a particular geographic area. I have seen primaries with three single conductors, each in a separate steel conduit. I have seen parallel single conductors.
It depends on the size, the voltage, the industry and the preference of the designer.
In general I know of no reason to use only single conductor cables for transformer connections.
There may be specific installations where it is desirable to use only single core cables but I can't think of any just now.
Bill
--------------------
"Why not the best?"
Jimmy Carter