Generation Transmission and Distribution

GENERATION TRANSMISSION AND DISTRUBUSTION

The main components of Power System are:

1. Generating Station

2. Transmission lines

3. Distribution system.

Principles

Generating station and distribution system are connected through transmission lines, which are connected to one power system to another. Distribution system is connected to all loads in a particular area to the transmission lines. From the Fig.5.2 the electric power is 'generated' at a voltage of '11 kV to 25 kV' which then is stepped up to the 'transmission level' in the range of '66 to 400 kV'

As the transmission capability of a line is 'Proportional' to the 'square' of the voltages. For long distance transmission, DC transmission 400 kV is used, and the line is connected to the AC system at the two ends through transformer are used.

The first step down of voltage from 'transmission level' is at the bulk power substation, where the reduction is to a range of '33 kV to 132 kV' depending on the transmission line voltage. The next step down in voltage is at the distribution substation.

Normally two distribution voltage level are employed.

1. Primary or feeder voltage (11 kV)

2. Secondary or consumer voltage (415 V/230 V)

The distribution system, from the distribution transformer station, supplies power to Domestic or industrial consumer. This the power system operates at various voltages levels separated by transformer.

Generating Stations

Generating stations feeds energy from one form into another which taps the energy. The input of electrical energy is generated in hydro, thermal and nuclear power stations. Electric power is generated at a voltage of 11 to 25 kV which then is stepped up to the transmission levels in the range of 66 to 765 kV.

Transmission Stations

The generated power is transmitted through transmission line. The voltage is stepped up by using step-up transformer from the sending end substations. It transmit the voltage 132 kV. From the receiving end substation, the voltage is stepped down. The first step down of voltage from transmission level is at the bulk power sub station, where the reduction is to a range of '33 to 132 kV' depending upon the transmission line voltage.

Distribution Stations

The next step down in voltage is at the distribution system. The distribution system, fed from the distribution transformer stations, supplies power to domestic, or industrial and commercial consumers.

The secondary voltage is 415 V for 3 phase and 230 V for single phase.