Electricity is generated at central power stations and then transferred to loads (i.e, Domestic, Commercial and Industrial) through the transmission and distribution system. A combination of all these systems is collectively known as an Electric Power System.
A power System is a combination of central generating stations, electric power transmission system, Distribution and utilization system. Each one of these systems is explained in detail in the next sections.
The transmission of electric power from a power station to consumers’ premises is known as the electric supply system.
An electric supply system consists of three principal components viz., the power station, the transmission lines and the distribution system. Electric power is produced at the power stations which are located at favourable places, generally quite away from the consumers. It is then transmitted over large distances to load centres with the help of conductors known as transmission lines. Finally, it is distributed to a large number of small and big consumers through a distribution network, supply system can be broadly classified into (i) d.c. or a.c. system (ii) overhead or underground system.
Nowadays, 3-phase, 3-wire AC system is universally adopted for generation and transmission of electric power as an economical proposition. However, distribution of electric power is done by 3-phase, 4-wire a.c. system. The underground system is more expensive than the overhead system. Therefore, the overhead system is mostly adopted for transmission and distribution of electric power.
Power system analysis is an essential part of an electrical power system design. Calculations and simulations are performed to verify that the electrical system, including the system components, are correctly specified to perform as intended, withstand expected stress and be protected against failures.