High power transformers are required to connect generating plants to transmission lines and to interconnect high voltage networks that carry hundreds or thousands of megawatts. They step up generator voltage to transmission levels to reduce current and I²R losses over long distances, and step it back down at receiving substations. Their high MVA ratings and robust insulation systems allow grids to move large blocks of power safely, keep voltage within limits and maintain stability even under faults, switching events and heavy load conditions.