Hyundai’s Alabama facilities conduct factory acceptance tests (ratio, impedance, losses, insulation, partial discharge, and withstand tests) before shipment. Refurbishment cycles may include bushing replacement, OLTC inspection, gasket renewal, corrosion control, oil filtration/degasification, and relay upgrades. After refurbishment each transformer is re-tested to verify compliance with IEC/IEEE standards before being returned to substation service.