Power Generation, Transmission, and Distribution
This domain spans the generation chain through transmission to the customer. Understand the synchronous generator's role: it sets frequency (governor) and voltage (excitation/AVR), and its real power follows the load-frequency balance while reactive power follows voltage. Know the merit-order and load-duration concepts: cheapest baseload plant runs first, peaking plant last.
For transmission, grasp why high voltage is used - power loss in a line is I²R, so raising voltage for the same power reduces current and loss. Know the standard voltage levels, the role of reactive compensation (shunt capacitors raise voltage, reactors lower it), and the Ferranti effect (receiving-end voltage rises above sending-end on a lightly loaded long line due to line charging capacitance).
For distribution, distinguish radial, ring, and interconnected topologies; radial is simplest and cheapest but least reliable. Know primary versus secondary distribution, and the meaning of voltage drop limits (commonly a few percent at the customer terminals).
Worked example: A line carries 100 A with 0.5 Ω resistance; loss = I²R = 100² × 0.5 = 5000 W. If voltage is doubled for the same power, current halves to 50 A and loss falls to 50² × 0.5 = 1250 W - a quarter of the original. This illustrates the I²R square-law benefit of higher transmission voltage.
Traps: confusing real and reactive power flow direction with voltage magnitude; assuming the Ferranti effect means a fault; and mixing up generation, transmission, and sub-transmission voltage tiers.