What is the purpose of using step-down transformers in transmission lines and step-up transformers at distribution substations?

Purpose of step-down transformers in transmission lines

Adapt to user power consumption: The voltage in transmission lines is high and not suitable for direct use. oil immersed  step-down transformers reduce the voltage to a safe level to meet the power needs of end-users such as households and enterprises.

Protect electrical equipment: Most electrical appliances can only operate properly at a specific voltage. Reducing the voltage can prevent electrical appliances from being damaged by high voltage.

Purpose of step-up transformers in distribution substations

Reduce transmission losses: The voltage generated by power plants is low. After oil type step-up transformers increase the voltage, the transmission current decreases, thus reducing the power losses in the transmission lines and enabling efficient long-distance power transmission.

Match line standards: Transmission lines have specific voltage requirements. Three phase step-up transformers increase the generated voltage to make it meet the operating standards of the lines.