Investigation of the dynamic rating of tubular busbars in substations.

In recent years, Austrian Power Grid AG (APG) has successfully introduced dynamic line rating for the weather-dependent determination of the current-carrying capacity on various overhead lines. The higher current loading of overhead lines also increases the current loading in substations. In some cases busbars appear to be the new limiting element. As weather-dependent operation of tubular busbars is not yet in practice, a physical model working in a similar way as dynamic rating for overhead lines has been developed and evaluated. Due to the significantly larger surface area of tubular busbars compared to conductors of overhead lines, radiation as well as absorption and convection have a greater influence on the current-carrying capacity of tubular busbars than of conductors of overhead lines. Calculations of the current-carrying capacity of a tubular busbar based on the weather data over one year show that the current-carrying capacity can be regularly increased by several ten percentage points. In the near future, dynamic rating will be used for tubular busbars at APG in network operation to be able to significantly increase the current-carrying capacity of busbars in suitable ambient conditions. [ABSTRACT FROM AUTHOR]