Compact lines for urban areas: a new solution

After an introduction which summarizes the main requirements of compact power lines for urban and suburban areas, the authors describe a new solution which meets the above requirements at low cost. This new solution considers towers with a pivoted base, free from longitudinal resistance (bidimensional structures). The frame type towers (triangular trestle) are made of a few slender members in cold formed `tubular-like´ sections. Details on line and towers conception and behaviour are given together with the analyses performed through mathematical models, dynamic reduced scale model, and full scale tests. The authors finally refer to the construction of a double circuit 132 kV line of the new type in a Florence suburb. This line was commissioned in June 1987 and is currently providing a very successful operating experience