Moskvitin E. Methods of controlling ageing the impregnated paper insulation of power cables an average voltage

Object of research - processes of ageing of insulation of power cables of the atomic power station and energonetwork. The work purpose - working out of a quality monitoring of ageing of the paper-impregnated insulation of power cables of average voltage on number of double excesses of a cable paper and a tangent of a corner of dielectric losses of phase and zone insulation separately. Research methods: theoretical - a physical and chemical, physical-statistical; methods of mechanics of destruction of a cable paper; direct and cumulative methods inspections of power cables in a protective metal cover on a tangent of a corner of dielectric losses; a method of electrothermal analogies; experimental - statistical methods of processing results the control; nonparametric methods of the statistical analysis of fatigue durability of a cable paper in the course of thermal ageing on the basis of criterion Tukey; methods correlation and regression analysis of dependences between number of double excesses and a tangent of a corner of dielectric losses. Theoretical and practical results - a quality monitoring of ageing of the paper-impregnated insulation of power cables of average voltage. Novelty - the quality monitoring of ageing of the phase and zone paper-impregnated isolation of power cables on number of double excesses of a cable paper is developed. It is experimentally established, that the curve of statistical density of distribution of number of double excesses of not made old cable insulation is not symmetric unimodal. The available maximum which is observed, answers durability level, i.e. accurately expressed value of number of double excesses near which the measured values are grouped. It is experimentally established, that for extremely aged cables durability levels degenerate. On variation diagrammes of number of double excesses for zone insulation the break is observed. The quality monitoring of ageing of the paper-impregnated insulation of power cables on a tangent of a corner of dielectric losses of individual characteristics of phase and zone isolation which is based on cumulative measurements of dielectric parametres of the paper-impregnated insulation and the decision of system of the linear algebraic equations for a finding of individual characteristics of components of isolation is developed. The method of not destroying control of power cables on a tangent of a corner of dielectric losses and a constant of time of the self-category of the paper-impregnated insulation which allows to reveal the nature of defect of a cable line is offered. Introduction degree - in state budgetary at the control of power cables of average voltage with the paper-impregnated insulation of power units of the atomic power station and regional electric systems, in educational process NTU "KhPI". Application sphere - power units of nuclear stations, regional and city electric systems.