Answer: Transmission and distribution lines are both critical components of the electrical grid, but they serve different functions. transmission lines are the "highways" of the electrical system. They are designed to carry bulk electrical energy at very high voltages (typically 69 kV and above) over long distances, from power plants to substations. Distribution lines, on the other hand, act as the "local streets." They carry electricity at lower voltages (typically 35 kV and below) from substations to individual homes, businesses, and industries.