A Method for Higher Accuracy Ampacity Calculation of Rectangular, Universal Angle, and Integral Web Substation Bus

摘要

Substation bus ampacity calculations perform a steady-state heat transfer analysis on a unit length of bus. In this analysis, the convective heat transfer coefficients for rectangular, universal angle bus (UAB), and integral web bus conductor (IWBC) have historically been calculated by applying flat plane correlations to the individual bus surfaces. The research presented here will show that the Nusselt correlations developed for the specific bus, similar to what is currently used for round bus, increases accuracy in bus ampacity predictions. Additionally, the correlations are easier to use and less likely to result in calculation error. This paper presents natural and forced convection correlations for rectangular, universal angle bus, and integral web bus.