Power transmission – transformers and losses ΔP = P²R/U²

Design & TechnologyElectrical Engineering & SafetyAges 17–18

Electricity travels from the power plant through a step-up transformer, a high-voltage line and a step-down transformer to reach consumers. Choose a transmission voltage of 22 kV, 110 kV, 220 kV or 500 kV, and drag the line length and wire cross-section to see the line resistance R = ρL/S, the power loss ΔP = P²R/U² and the transmission efficiency change; the wire glows red when the loss is large. A bar chart comparing the loss at all four voltage levels shows why power must be transmitted at high voltage.