These towering structures, typically ranging from 40 to 200 feet in height, serve as the essential support framework for high voltage power lines that carry electricity across vast distances from generating facilities to distribution networks. In some areas, individual utilities operate their own transmission networks. In other parts of the country, coordination, control, and monitoring of single-state or. A distribution transformer or service transformer is a transformer that provides a final voltage reduction in the electric power distribution system, stepping down the voltage used in the distribution lines to the level used by the customer.