What best describes the main function of a generator in a power distribution system?

The main function of a generator in a power distribution system is to convert mechanical energy into electrical energy. This process typically involves using a rotating turbine, which can be driven by various energy sources such as steam, water, or wind. As the turbine spins, it turns the generator's rotor within a magnetic field, inducing electric current in the stator windings. This transformation is fundamental to power generation, as it is the initial step that enables electrical energy to be produced for consumption.

While the other options play significant roles within the power distribution system, they do not capture the primary function of a generator. For instance, voltage regulation is essential for maintaining stable power delivery but is a function that occurs after generation, often handled by transformers. Storage units, such as batteries, are critical for managing supply and demand but do not pertain to the generating process. Finally, distribution of power to end-users is a system operation following generation and involves elements like transmission lines and substations. Thus, the correct choice focuses specifically on the generator's role in the conversion process.