A Mathematical Model of Transmission Line Audible Noise Part 1: Background and Model Development

A mathematical model is developed for transmission line corona audible noise (AN). The noise is described as the sum of the noises from a number of uncorrelated sources on the surface of the conductor. The intensity of each source is assumed to be a function of gradient and the number of sources is a function of rain rate, voltage gradient and the surface aging condition. Townsend's first ionization coefficient is used to relate the number of sources to the gradient. The steady state solution of the AN equation is plotted to show the variation of noise with gradient for various rain rates, and the variation of noise with rain rate for various gradients.