The evaluation of the descriptive statistics usefulness in the analysis of interfering signals generated during operation of a power transformer

摘要

The paper will present the results of the comparative analysis of descriptive statistics descriptors determined for various sources of interfering signals that can occur during diagnostic measurements of power transformers taken by the acoustic emission method. In order to establish the properties occurring in a given test representing a given source of acoustic disturbances and between the particular tests representing various types of disturbances at the stage of an initial aggregation of data, descriptive statistics were used. They provide synthetic information on the way of arrangement of figures in a test, i.e., for example, on their location, trends, concentration, dispersion, symmetry, distribution in relation to a given number, and other data referring to mutual connections and dependencies between the constituent elements of a test. For each test histograms runs and corresponding density curves were determined and then the values of the indexes that were the measures of location, dispersion, asymmetry and concentration of the AE pulses measured, generated by the particular PD forms were determined. The characteristics of the descriptive statistics indexes was supplemented with the runs of box diagrams, scatter and symmetry, which were determined separately for each test representing the acoustic emission pulses generated by basic types of disturbances measured, which can influence the results obtained by using the acoustic method of measurement of partial discharges occurring in paper-oil insulation systems of power appliances.