A Tethered Drone Power System (TDPS) represents a paradigm shift in unmanned aerial vehicle capabilities by solving the most critical limitation of battery-powered drones - limited flight endurance. This innovative system functions as an unmanned aerial vehicle's "umbilical cord," comprising three core components: a ground-based power source (typically a generator or grid connection), a specialized tether cable containing power conductors and fiber optics, and an onboard power management unit. By delivering continuous electrical power through the tether, TDPS enables unprecedented flight durations ranging from 12 to 24 hours or more, effectively creating a persistent aerial platform that transcends conventional drone limitations. The system's engineering brilliance lies in its multi-functional tether design, which simultaneously transmits high-voltage power for efficient long-distance energy transfer while providing secure, low-latency data communication through integrated fiber optics. This dual-capability architecture allows tethered drones to maintain stable hover positions while supporting power-intensive payloads like high-resolution cameras, communications relays, or surveillance systems indefinitely. The applications span critical sectors including public safety for prolonged incident monitoring, emergency response for temporary communications infrastructure, border security for continuous surveillance, and broadcasting for sustained aerial coverage. While the system imposes operational radius limitations defined by tether length (typically 100-200 meters) and requires more complex deployment procedures than free-flying drones, its advantages prove decisive for missions demanding uninterrupted aerial presence. The technology has evolved to incorporate sophisticated features like automated tether management systems, power redundancy safeguards, and environmental hardening, making TDPS the solution of choice for military, industrial, and governmental applications where reliability and endurance outweigh mobility requirements. By transforming drones from short-duration tools into persistent aerial assets, tethered power systems have created an entirely new category of unmanned operations that continue to expand across defense, commercial, and public service domains.