Why generation power is 11kv in india.why not 33kv,66kv?

Question

Why generation power is 11kv in india.why not 33kv,66kv?

Answer 1

Possibly because the infrastructure can't stand the extra voltage.

The insulator properties have to be much better when you have the higher voltages and if they aren't then you have to stick with what they can cope with.

Answer 2

Bulk electric power generation is performed at medium voltage, typically between 4 - 25 kV because the electric machines are optimal in this range.  It is possible to build machine that operate at higher voltages, but the additional insulation required drives up the machine size (or frame) significantly.

Similarly, at the other extreme, the conductor mass and heating requirements do not readily support generating 10's or 100's of MW at low voltages.

Answer 3

In India, Electric power is normally generated at 11-25kV in a power station. To transmit over long distances, it is then stepped-up to 400kV, 220kV or 132kV as necessary. Power is carried through a transmission network of high voltage lines. Usually, these lines run into hundreds of kilometres and deliver the power into a common power pool called the grid. The grid is connected to load centres (cities) through a sub-transmission network of normally 33kV (or sometimes 66kV) lines. These lines terminate into a 33kV (or 66kV) substation, where the voltage is stepped-down to 11kV for power distribution to load points through a distribution network of lines at 11kV and lower.

The power network, which generally concerns the common man, is the distribution network of 11kV lines or feeders downstream of the 33kV substation. Each 11kV feeder which emanates from the 33kV substation branches further into several subsidiary 11kV feeders to carry power close to the load points (localities, industrial areas, villages, etc.,). At these load points, a transformer further reduces the voltage from 11kV to 415V to provide the last-mile connection through 415V feeders (also called as Low Tension (LT) feeders) to individual customers, either at 240V (as single-phase supply) or at 415V (as three-phase supply). A feeder could be either an overhead line or an underground cable. In urban areas, owing to the density of customers, the length of an 11kV feeder is generally up to 3 km. On the other hand, in rural areas, the feeder length is much larger (up to 20 km). A 415V feeder should normally be restricted to about 0.5-1.0 km. Unduly long feeders lead to low voltage at the consumer end.