What is the role of a step-up transformer in a hydroelectric power plant?

The primary role of a step-up transformer in a hydroelectric power plant is to increase the voltage of the electricity generated by the generators to a higher voltage level suitable for efficient transmission over long distances on the power grid. Hydroelectric generators typically produce electricity at a relatively low voltage, such as 13.8 kV or 18 kV. Transmitting power at these low voltages over long distances would result in significant energy losses due to the high current and resulting resistive losses in the transmission lines (I²R losses). By stepping up the voltage to a higher level, such as 115 kV, 230 kV, or 500 kV, the current is reduced proportionally, significantly reducing transmission losses and improving the overall efficiency of power delivery. The step-up transformer is typically located in the plant's switchyard, close to the generators, and connected to the high-voltage transmission lines. The selection of the appropriate step-up voltage depends on the distance to the load centers and the capacity of the transmission grid. For example, a hydroelectric plant located far from load centers would require a higher step-up voltage than a plant located closer to the demand.