Optical Transport Network (OTN) is a high-capacity, carrier-grade optical technology that efficiently transports and manages diverse data types, Ethernet, SDH, IP, and moreover a single fiber network. In the power grid, OTN delivers a reliable, scalable, and secure backbone that unifies mission-critical operational traffic (SCADA, teleprotection, automation) with corporate IT services (voice, video, data), while ensuring strict QoS and network isolation.