What is the primary function of a substation in electrical systems?

The primary function of a substation in electrical systems is to transform electricity from high to low voltage or vice versa. Substations are critical components of the power grid and serve several essential roles in managing electrical transmission and distribution. When electricity is generated at power plants, it is usually at a high voltage to allow for efficient long-distance transmission. Once it reaches a substation, the voltage needs to be decreased to a level that is safe and usable for residential and commercial consumers. This transformation is accomplished through transformers within the substation.

Additionally, when generating stations require electricity from the grid, substations can step up the voltage to facilitate efficient transmission over long distances. Therefore, the ability to transform voltage levels is fundamental to the operation of the entire electrical system, ensuring that electricity is delivered efficiently and safely to end-users. This is why option B accurately captures the primary function of a substation.