Define transmission and distribution. Draw layout of generation, transmission and distribution of power. Give brief explanation.

(a) Transmission: It is the system of delivering bulk power from generating station to substations/control stations.

Distribution: It is the system in which power is distributed to consumers from the substation/control station.

(b) Layout of a system is shown in Fig. 1.

Fig. 1

(c) Power is generated at the generating station as 3 Phase a.c. at 11kV. It is stepped up by a transformer 11/220 kV for transmission over long distances.

It is further stepped down to 33kV for secondary transmission. For Primary distribution it is stepped down to 11 kV and is supplied to bulk consumers.

For small consumers it is stepped down to 3 phase 4 wire 440 V supply. For industrial consumer it is supplied at 440 V and for domestic consumers it is supplied at 230V.