Increasing thermal rating by risk analysis

Abstract

It has long been realized that the thermal ratings of overhead transmission lines when computed deterministically, are typically conservative, resulting in under-utilization of conductors. A probabilistic method to assess thermal capacity based on risk is presented in this paper. The authors address the potential impacts of thermal overload, the stochastic model of conductor temperature, and the quantitative risk which indicates the average "danger" of an overload. The continuous, short-time and long-time thermal ratings are calculated using the risk of thermal overload. This method can provide technical justification for increased thermal capacity for a transmission line and an evaluation of risk for the given operating conditions.