Answer / k.prakashchandra

Adv;-Voids are avoided and hence higher voltage is
possible,temp range and dielectric strength are increased ,
leakage can be detected easily. Disadv:-high initial cost
,laying and jointing are complicated.

Answer / anil

now most of the HT and EHV cables are with XLPE insulation.
earlier, in mid 70's HT cable are insulated with PILC(paper
insulated and lead covered. OIL is filled to reduce moisture
in paper. disd of PILC cables is very heavy almost double
the weight of XLPE cable but adv is the chance of voids are
very less in PILC cable. Lead is not ECO-friendly,it is
almost banned in europe, US and few countries in ASIA. Cost
is very High as compare to XLPE cable. whereas XLPE cable
are lighter in weight.Long life,easy to handle. jointing is
less costly.

Answer / jason008

The oil cable was designed very earlier way before the 70.
There are earlier lead sheath designed cable but the newer
cables are alum sheath this change decreases the chance of
a cable leak mid cable.The cable oil fills the butt gap
which are there to allow the cable be bent without tearing
the paper insulation.The oil is the second form of
insulation it has a very goog dieletric stregth it also is
there to asborb gases the may be made during in service
operation. This allows us to see what is happening in the
cable. partial discharge overloading ect ect these cables
are opererated at very high voltages 33kv 66kv 132kv 225kv
uk 330kv aust 400kv uk they are now starting to produce
xlpe with better dielectric which are almost similar to oil
cable losses.the xlpe is a negative pressure cable which
may allow for the migration of water into the cable. xlpe
is more maintenance free except for link boxes. The oil
these days are biodegrable they us t3788 dusket make this.

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