New transmission lines are being built to meet growing demands for electricity, improve reliability of power delivery, and meet requirements for procuring larger percentages of energy from renewable sources. As new transmission corridors are approved and the projects are initiated, the FAA requires notification by utilities of the construction or alteration of any structure that may affect the National Airspace System. This includes towers located in or around airport influence areas, military bases, United States border areas, and hospitals using helicopters for medical airlift. The FAA requirement not only applies to new transmission and distribution lines, but it also applies to many existing transmission and distribution lines which are not yet meeting FAA lighting requirements.

After the utility has notified the FAA of its transmission structures, the FAA conducts an aeronautical inspection to see if the structure(s) require obstruction lighting. The FAA Advisory Circular (AC 70/7460-1K) requires that once required obstruction lighting is installed, “any failure or malfunction that lasts more than thirty (30) minutes and affects a top light or flashing obstruction light, regardless of position, be reported immediately to the appropriate flight service station (FSS).” Monitoring of light function can be done by visual or automatic means, but given that transmission corridors are typically located in remote areas where cellular communication is unavailable or unreliable, most utilities must use visual means to monitor the light operations.  In some cases, this requires dispatching trouble crews or helicopters daily, representing a significant operational cost burden to mitigate the potential risk for fines or other damages should an accident occur. Utilizing automation to satisfy FAA monitoring requirements avoids the costs of manually checking towers, which for a utility that manually monitors 100 towers, can cost up to $1M in annual operational costs.

Evaluating an Automation Solution

When evaluating an automated obstruction light monitoring solution, utilities should consider several components. Most importantly, the solution should be based on a pervasive and reliable wireless network, and provide timely information to support FAA reporting requirements. 

Unfortunately, many of the automated monitoring solutions available today are built on a single-use network relying on commercial cellular service for connectivity to monitored obstruction lights. As mentioned, many transmission towers are located in remote areas with little to no cellular communications. Even if the cellular network is available and reliable, this service can become congested with higher priority traffic during major catastrophes or events such as large scale power outages, earthquakes, hurricanes, etc.  There are wireless automation solutions available, however, which allow a utility to cover the hardest to reach assets, reliably meet FAA monitoring and utility smart grid requirements, and maintain a very high capacity for supporting a range of smart grid applications on the same network.

Other critical components of an automation system include:

·         Support for various L-810, L-864, and L-864/865 lighting systems

·         Support for infrared lights used in non-FAA obstruction marking requirements such as military or border patrol operations

·         The ability to monitor light status directly (L-810) or monitor the lighting controller (L-864/865)

·         Ability to rapidly accommodate new lighting requirements

·         Alarms for intrusion detection, low back-up battery, and primary power system failure

·         Low power design using lighting system power (AC or solar recharged DC battery) for primary power, and internal back-up battery for  ongoing communication through primary power failure

·         Simple deployment – use of LEDs and test mechanisms validate operational system status real-time during installation

·         Reliable outdoor operation in high EMF and EMI environments typical in up to 500 kV transmission lines and substations.

·         End to end utility-grade reliability and security of the information network.

As utilities continue to upgrade existing and new transmission lines to meet FAA regulations, they should use the criteria above to evaluate how their automation system options to address regulatory, schedule and budget realities.


Posted by Janine E. Mooney, Editor

May 29, 2012