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Overhead Line Design Issues & Wind And Ice Storm Mitigation

Overhead Transmission Lines (OHL) often face severe ice or wind loads which may damage line sections and affect power supply to customers. Even when the best design criteria are met, there continues to be a risk of extensive damage to overhead lines when extreme wind or ice storms exceed the design criteria. Moreover, utilities should not ignore the anticipated effects of global warming and the substantial changes of climatic loads which might occur.

There are many approaches to limiting the impact of ice and wind loads on overhead lines. One may focus on a better knowledge of climatic events and their impacts on OHL, advancements in design, mitigation techniques or mutual assistance efforts.

  • Climatic stations for recording ice or wind parameters and modeling for a better forecast of maximum loads.
  • Careful selection of the design approach minimizes the risk of failures, while simultaneously reducing the potential consequences of such events.
  • Mitigation techniques deal with the reduction of the consequences of exceeding the design loads or to avoid failure of installations by reducing ice accretion or by using de-icing techniques.
  • Mutual assistance efforts focus on the sharing of resources, such as workers, logistics, equipment and components, in the event of serious damage.

Experiences with the 1998 ice storm in northeastern Canada and the U.S., several smaller ice storms, hurricanes and High Intensity Winds (HIW) recently occurring in many countries have demonstrated the devastation severe weather causes to transmission systems. These problems may best be addressed by improving knowledge and technologies, and by sharing the needed efforts on research and studies. The coalition of information on the most efficient storm management methods, collaboration on joint R&D projects and amalgamation of logistics and spare material will benefit all participants in this Interest Group.

Topics and Issues:

  • Utility approaches to crisis management
  • De-icing techniques during and following ice storms
  • Failure containment and load control devices
  • Prediction and real-time monitoring of loads
  • Design for High Intensity Winds
  • Inspection techniques to detect latent damage and aging
  • Assessment of existing conductor vibration recorders
  • Simulation of conductor galloping and galloping mitigation device assessment
  • OHL protection against lightning without impairing line strength under ice loads