1. The document discusses the main components of a hydroelectric power station, which utilizes the potential energy of water at a high level to generate electrical energy. 2. The key components include the water head, canal, dam, gates, penstock, turbine, generator, and yard. Turbines can be impulse types like Pelton wheels for high heads or reaction turbines like Francis and Kaplan for low to medium heads. 3. The document also outlines how hydroelectric power systems work and provides diagrams of the layout of the power system from the power house to transmission including transformers, bus bars, and grid stations.