How does a tethered power supply box provide continuous and stable power for drones operating at high altitudes?
Publish Time: 2025-09-03
Under traditional battery power, the flight time of consumer and industrial drones is generally limited, typically only 20 to 40 minutes. This severely restricts their application in scenarios requiring prolonged hovering, such as emergency communications, border surveillance, disaster reconnaissance, and high-altitude lighting. To overcome this bottleneck, the tethered power supply box emerged as a core technology enabling drones to achieve "ultra-long hovering." By combining ground power supply, cable transmission, and intelligent management, the tethered power supply box provides continuous, stable, and efficient power for high-altitude drones, enabling 24/7 uninterrupted operation and revolutionizing traditional drone operations.1. Continuous Power Supply: Breaking Free from the Physical Limitations of Battery LifeThe core principle of the tethered power supply box is "ground power, air flight." It connects the ground power supply to the drone via an integrated cable (tether), replacing or supplementing the power supply provided by the onboard battery. The ground-based power supply box connects to mains electricity, a generator, or a vehicle power source, converting AC power into high-voltage DC suitable for drones. This power is then transmitted via a cable to the drone's onboard power management module, where it is then stepped down and regulated before being supplied to the flight control system, motors, and payload. Since the primary power source is ground-based, the drone eliminates the need for large-capacity batteries, significantly reducing weight and eliminating battery capacity limitations. As long as the ground power supply remains constant, the drone can fly continuously, enabling "as long as desired" operations. This feature makes it an irreplaceable advantage in scenarios requiring long-term aerial surveillance, such as emergency command, large-scale event security, and forest fire monitoring.2. Stable Output: Ensuring Reliability in High-Aerial OperationsContinuous power supply is only the foundation; power stability is crucial for safe drone flight. The tethered power supply box incorporates a high-performance AC-DC or DC-DC converter module with a wide input voltage range and highly accurate output voltage regulation. This ensures constant voltage and current for the drone, even with power grid fluctuations or generator load variations. In addition, the power supply box is equipped with multiple protection mechanisms, including overvoltage, overcurrent, short circuit, overtemperature, and reverse polarity protection. Upon detecting an anomaly, it shuts off output in milliseconds to prevent damage to the cable or drone. Some high-end systems also feature intelligent power matching, dynamically adjusting output parameters based on the drone's real-time power consumption to optimize energy efficiency and avoid resource waste.3. Efficient Transmission: Reducing Energy Loss in Long-Distance CablesTethered cable lengths typically range from 100 to 300 meters, with some systems exceeding 500 meters. Long-distance power transmission inevitably introduces cable losses. To reduce energy loss, tethered power supply boxes generally utilize high-voltage direct current (HVDC) technology (e.g., 400V or higher). This reduces the transmission current at the same power level, significantly reducing cable heating and voltage decay. Furthermore, the cable utilizes lightweight, high-strength materials (such as Kevlar reinforcement) and low-resistance conductors (such as silver-plated copper wire) to further enhance transmission efficiency. The ground terminal is also equipped with an intelligent cable retraction system that automatically controls cable release and retraction, preventing damage from entanglement, kinking, and excessive tension, ensuring continuous and secure power transmission.4. Environmental Adaptability and System IntegrationTethered power supply boxes typically adopt an IP54 or higher protection rating, offering dust, water, and shock resistance. They operate stably in complex environments such as rain, snow, sand, and high and low temperatures. Their modular structure makes them easy to transport and quickly deploy, making them suitable for various platforms, including vehicles, ships, and mobile command vehicles. Furthermore, the power supply box can communicate with the drone's flight control system and ground station, providing real-time monitoring of parameters such as voltage, current, temperature, and cable status. This supports remote diagnosis and fault warning, enhancing the overall system's intelligence.5. Typical Application ScenariosEmergency Communications: When disasters such as earthquakes and floods disrupt communications, tethered drones can be equipped with communication relay equipment to establish temporary base stations at an altitude of 300 meters, covering an area of several square kilometers and ensuring smooth rescue operations.Security Monitoring: At large gatherings and sporting events, drones can hover for extended periods, equipped with high-definition cameras or infrared equipment, for comprehensive, real-time monitoring.Fire Reconnaissance: During high-rise building fires, drones can be launched to scout the fire, locate trapped personnel, and provide critical information for rescue operations.Marine and Energy Inspection: In remote areas such as offshore wind farms and oil platforms, tethered systems enable drones to conduct long-term inspections, reducing labor costs and safety risks.The tethered power supply box successfully addresses the pain point of short drone flight range through ground-based power supply, high-voltage transmission, intelligent management, and reliable connectivity, ensuring a continuous and stable power supply at high altitudes. This represents not only a revolutionary upgrade in drone technology but also a key enabler for the transformation of drones from short-duration flight vehicles to long-term aerial platforms.
