Subject of research: is the technique of identification СCL in electric power system knots.
Purpose of research: consists in working out of a technique of monitoring of changes КREL in electric power system knot.
Methods of research: imitating modelling of electric modes, digital processing of signals, method of natural experiment.
Main results of research: the technique of monitoring КREL of knot of an electric power system of digital processing of the information based on a method has been as a result developed, having author's specific features, also has criteria of suitability of data and the device realising a technique is developed. Experimental approbation of work of the device analyzing data from means of a telemetering, an operatively-measuring complex or automated data management system is spent. Device check has shown, that on an indication range 0,75 1,2Uном the error of identification КREL has made 0,2 % that speaks about high reliability of an offered technique of actualisation КREL.