A multistage technique for current transformers with current ratios of less than unity

An overview of the development and performance of a current transformer with current ratios of less than unity at the National Research Council of Canada (NRC) is described. A prototype current transformer with a current ratio of 0.025A/1A that can be operated at up to at least ten times the rated current (secondary current up to ges 10 A), with ratio errors of less than 20times10^-6 in both magnitude and phase with burdens up to 0.1 Omega and at frequencies up to 1000 Hz has been developed.