Helicopter laser surveys of improperly sagged fiber cable or conductors

Do you really know how far your transmission line conductors and fiber cables are sagging?

In the case of decades-old high voltage (100 kV) transmission lines, questions may exist as to how accurately conductor sags and tensions are reflected in utility documentation; conductor creep properties were often not accurately modeled before the advent of computer tools in the 1960s. As a result, current conductors sags can be as much as 5 to 10 feet off their predicted locations in utility technical records. Correct conductor sag information may be required to design ADSS installations to avoid conductor-ADSS clashes on these routes. (This is not an issue for OPGW installations above the top conductor.)

Furthermore, since the original designers usually designed conservatively to compensate for future error, actual sags may be less than predicted, allowing utilities to safely up-rate the capacities of these older lines if the actual current sag parameters are known, resulting in major economic benefits to the utility.

Fiber Planners has also been called in after the fact to determine the extent of improper sagging after an installer apparently incorrectly installed many miles of fiber cable on a high voltage transmission at unknown and unrecorded tensions, not those specified by the customer.

After spot checking sags ourselves and determining problems existed, Fiber Planners has used John Chance Surveyors' FLI-MAP helicopter laser surveys to rapidly and very precisely determine and model (using PLS-CADD software) the exact sag and tensioning of existing conductors and fiber optic cables.

Back to Specialized technical services page.

• Industry standards development
• Technical assistance to vendors
• Failure analysis and litigation consulting
• OTDR analysis and training
• Technical note publishing
• Helicopter laser surveys of inaccurately sagged fiber cable or conductors
• PLS-CADD modeling
• Feasibility studies of internal and dark fiber projects
• Telecommunications network design optimization
• Materials testing/replicating field failures