Open Calculators

Free Transmission Line Calculators for Utility Engineers

These tools are provided as a resource for the utility industry and are suitable for estimating and conceptual design. Each calculator has been reviewed for accuracy by an experienced and licensed professional engineer. However, the tools are provided as-is and users should independently validate all results.

• Underground Cable Length Estimator

  Estimates the maximum theoretical and practical length of AC underground cables based on thermal rating, cable geometry, and reactive power limitations. Includes surge impedance loading (SIL) calculation of underground cables.

• Optical Ground Wire (OPGW) Short Circuit Thermal Rating Estimator

  Calculates the kA²-sec short circuit thermal rating of optical ground wire, including the effects of DC offset and high-speed reclosing.