In a conventional power station, the main transformer sits between the generator and the transmission switchyard. Turbine-generator sets produce electricity at relatively low voltage (for example 11-24 kV). The generator step-up (GSU) transformer immediately raises this to high or extra-high transmission voltage for efficient long-distance transfer. Auxiliary and station service transformers are placed on the generator or grid side to feed pumps, fans, lighting, and control systems that support the conversion cycle.