Testing procedure for evaluating diffusion and leakage currents in insulators

摘要

A method for predicting long-term electrical insulation properties of composite materials in a moist environment is disclosed. The method includes: (a) providing a specimen in the form of a hollow-core cylinder; (b) subjecting the specimen to a high voltage; (c) testing the specimen to determine absorbed moisture content values and leakage current values of the specimen at predetermined time intervals; (d) determining a moisture-leakage current factor from the absorbed moisture content values and leakage current values; and (e) using the moisture-leakage current factor to determine electrical insulation properties of the specimen. A further method for predicting long-term electrical insulation properties of composite materials in a moist environment is disclosed. The method includes: (a) providing a specimen in the form of a hollow-core cylinder; (b) exposing the cylinder to a diffusible fluid; (c) at predetermined intervals: (i) measuring a moisture content of the cylinder due to absorption of the diffusible fluid; and (ii) subjecting the cylinder to a high voltage and measuring a leakage current in the cylinder; (d) determining a moisture-leakage current factor from the moisture content and leakage current; and (e) correlating the moisture-leakage current factor to standardized data to determine electrical insulation properties of the specimen. A further method for predicting long-term electrical insulation properties of composite materials in a moist environment is disclosed. The method includes: (a) providing a sample of composite material in the form of a hollow-core cylinder; (b) recording an initial mass of the cylinder; (c) recording an initial leakage current of the cylinder; (d) placing the cylinder in an environmental chamber; (e) subjecting the cylinder to a diffusible fluid; (f) removing the cylinder from the environmental chamber at predetermined time intervals, subjecting the cylinder to a high voltage and recording a mass and a leakage current of the cylinder; (g) determining an absorbed moisture content of the cylinder from the mass of the cylinder; (h) determining a moisture-leakage current factor from the moisture content and leakage current; and (i) using the moisture-leakage current factor to determine electrical insulation properties of the specimen.