Power systems

An electric power system consists of 3 principle sections

• Power stations: electricity is generated
• Transmission: voltage is stepped to high voltage
• Distribution: voltage is stepped down to medium voltage for distribution over a relatively small region

Variable load

Load on a power station changes with to uncertain demands of consumers. This is called the variable load.

Load vs time curve is called the load curve. Area under this curve is the total energy requirement.

Power grid

Nation-wide, massive, geographically distributed system for electrical power supply network.

Sri Lankan Voltage Levels

• High voltage
• Medium voltage
• Nominal voltage
• Nominal line-to-line