ELECTROMAGNETIC CURRENT CONVERTERS: OPERATING LIMITS

The urgency of the task is due to the desire to ensure the ideal transmission of primary relay protection signals to microprocessor devices. The article presents the materials of the comprehensive study of electromagnetic current converters from the standpoint of assessing the possibility of using them as current sensors in microprocessor relay protection systems. The study was conducted in order to assess the limiting capabilities of electromagnetic current converters by analyzing their methodological errors. To assess the methodological errors of electromagnetic current converters, the mathematical apparatus of the theory of automatic control is used. The possibility of representing electromagnetic current converters by dynamic links with linear transfer functions is shown. The amplitude and phase frequency characteristics are considered. Analytical expressions for the frequency characteristics of electromagnetic current converters are given. Concise visual mathematical expressions are proposed to determine the boundaries of the frequency range of electromagnetic current converters according to the main parameters of the substitution circuit. The limits of the application of linear transfer functions for the mathematical description of these converters are estimated. Examples of relay protection signals passing through electromagnetic current converters are considered. Recommendations for improving the conversion properties of electromagnetic current converters are given.