Influence of insulation model parameters on transfer function zero evaluated for diagnosis of oil-paper insulation

Abstract

Conventional Debye Model is commonly used for analysis of dielectric response function evaluated from Polarization and Depolarization Current data. The same Polarization current profile when fitted to obtain insulation model, may result in different number of branches depending on curve fitting parameter. Zero of Transfer Function (evaluated using insulation Model parameters) having highest magnitude can be used to obtain performance parameters like paper-moisture and dissipation factor. In this present work, polarization current data from laboratory sample is measured at two different temperatures. This is followed by formulation of Conventional Debye Model parameters from each measurement. The two resulting insulation model structures are not identical in terms of number of branches and parameters therein as branch parameters depend on curve fitting. This paper investigates the influence of varying branch parameters of Conventional Debye Model on the values of performance parameters that are evaluated using Zero of insulation model Transfer Function.