
— Technical Guidelines for Aviation Safety Marking of Overhead Transmission Lines in Airport Clearance Zones —
Aircraft warning lights are active-illumination safety marking devices installed on overhead transmission lines. They are primarily used to indicate the spatial position of transmission lines during nighttime and low-visibility conditions, preventing collision accidents between aircraft and transmission lines. In airport clearance protection zones, aircraft warning lights work in conjunction with aviation warning spheres to form a comprehensive aviation safety marking system.
According to the “Technical Specification for Aviation Warning Devices on Overhead Transmission Lines” (DL/T 288-2012) and relevant aviation safety standards, the installation positions of aircraft warning lights shall meet the following requirements:
Power Supply Method | Installation Position Requirements |
Inductive Power Harvesting | Must be installed on the highest transmission conductor, utilizing electromagnetic induction from conductor current |
Other Power Methods (Solar/Battery) | Installed on the highest line position |
Non-illuminated Type (Warning Spheres, etc.) | Shall be installed on the ground wire (overhead ground wire) |
At least 3 warning devices shall be installed on the line between two adjacent towers, with one device mandatory at the lowest point of the conductor sag (catenary curve) within the span. This marks the most hazardous lowest-height area of the line.
If illuminated warning lights are not installed on the highest conductor, non-illuminated warning devices (such as warning spheres) must be simultaneously installed on the highest ground wire. The vertical distance between the line with illuminated warning lights and the highest overhead line above it should preferably not exceed 8 meters.
Zone Type | Maximum Spacing |
Airport and Its Clearance Protection Zone | ≤40 meters (preferably 15 meters in critical flight areas such as near runway ends) |
General Areas | 120~150 meters |
All warning devices should be installed at equal intervals to uniformly mark the line profile.
For EHV transmission line towers, in addition to conductor-mounted warning devices, the tower itself must also be equipped with aviation obstruction lights:
Illuminated warning lights are typically mounted directly on the conductor using suspension clamps. The clamps must match the conductor diameter to ensure secure positioning without sliding. For inductive power harvesting types, the clamp also serves as the mounting fixture for the power harvesting coil and must be in close contact with the conductor.
Tower-mounted obstruction lights are installed on the outer side of the tower using dedicated brackets. They should be located within the lightning protection zone, with all metal parts of the luminaire effectively grounded or electrically connected to the lightning protection band. The mounting bracket must have sufficient mechanical strength to withstand wind loads.
Power Supply Method | Advantages | Disadvantages |
Inductive Power Harvesting (Mainstream) | No external power required, weather-independent, low maintenance | May not function properly when conductor current is too low |
Solar + Battery | Independent power supply, wide applicability | Affected by weather and sunlight conditions |
Dedicated Low-Voltage Supply | Stable and reliable power supply | Requires additional cabling, higher cost |
The core principles for installing aircraft warning lights on transmission lines are “mark the highest point, mark the lowest point, equal spacing distribution, and active illumination.” Through proper installation position selection, spacing control, fixing methods, and power supply solutions, aircraft warning lights can effectively function under various environmental conditions, providing reliable protection for aviation safety.
