Generation, Transmission and Distribution Basics
What the domain tests
Generation, Transmission and Distribution Basics tests the path from fuel or renewable source to the consumer, the reason for high-voltage transmission, and the meaning of feeder, distributor, load factor and diversity.
Core rules
- Generation: thermal, hydro, nuclear, solar and wind produce electrical energy; a generator typically produces at 11–25 kV.
- Step-up transformers raise voltage for transmission; high voltage reduces current for the same power, cutting I²R losses. Transmission voltages in India include 132, 220, 400 and 765 kV.
- Distribution steps down through substations to 33/11 kV, then 400/230 V for consumers. Primary distribution feeds distribution transformers; secondary distribution feeds service connections.
- Load factor = average load / maximum demand. Diversity factor recognises that not all consumers peak at once.
- A feeder supplies a distribution area; a distributor is tapped along its length for consumer connections.
Worked example
A 100 MW plant runs at 80% load factor for one day. Average load = 100 × 0.8 = 80 MW. Energy = 80 MW × 24 h = 1,920 MWh. If the same power were sent at 220 kV instead of 11 kV, the current would be 20 times lower, so line losses (I²R) would fall dramatically for the same conductor resistance.
Traps
Do not say high voltage reduces power; it reduces current and losses for the same power. Do not call a distribution transformer a generator step-up transformer. Do not calculate energy by multiplying maximum demand by time unless the load is actually at maximum throughout.