ISSUES OF IMPROVING THE MOISTURE CONTENT CRITERIA FOR THE INSULATION OF OIL-FILLED TRANSFORMERS IN THE CONTEXT OF THE DEVELOPMENT OF TECHNOLOGIES FOR ITS AUTOMATED RECOVERY

Abstract

The operational reliability of oil-filled transformers largely depends on the characteristics of the insulation, which is confirmed by the failure statistics. Moisture significantly affects both the reliability and the overload capacity and durability of power transformers. Drying insulation by traditional methods is a complex and expensive job, the complexity of which depends on the size of the transformer and the percentage of paper moisture, the more, the more difficult. An equally difficult task is to reliably measure the moisture content of the paper. To improve the accuracy of diagnosing insulation in terms of oil quality, changes are proposed to the requirements for the sampling procedure of a number of standards. To improve the efficiency of service maintenance of power transformers, improved criteria for the moisture content of solid insulation are proposed. The period of the most effective use of automated insulation restoration systems of the TRANSEC type has been determined. Field tests of the TRANSEC technology were carried out in an operating electrical installation. The high efficiency of automated insulation restoration systems was established, the dependence of insulation characteristics on temperature was confirmed, the admissibility of using the indicator of relative moisture saturation to assess the dynamics of the insulation restoration process, the comparability of the results of the measured and calculated values of paper moisture at an insulation temperature of at least 40 °C.