ANALYSIS OF EXISTING APPROACHES AND METHODS OF DIAGNOSTICS OF ON-LOAD TAP CHANGER OF POWER TRANSFORMERS

Abstract

In electrical networks of almost all voltage classes, the main link in the work on the transmission of electrical energy is a power transformer. At the moment, about 60% of them are operated in our country with a significant excess of service life, which increases the requirements for their technical control and diagnostics of all units. Switching devices are an integral part of power transformers. They are necessary to regulate voltage on substation busbars depending on the load of consumers. Not only the reliability of power supply of industrial enterprises, cities and agriculture, but also the quality of electrical energy depends on their operation. At the same time, they are one of the vulnerable nodes of voltage converters. Although the parameters of diagnostic signs for switching devices are not as extensive as the power transformer itself, they nevertheless require special attention from the operating personnel. This is due not only to the variety of switchgear types that exist, but also to the methods used to diagnose them. For this reason in this work an attempt has been made to analyze the existing approaches and methods of diagnosing these mechanical controlled voltage regulators. We propose a new approach in terms of diagnostics of high-voltage equipment, including power transformers – introdiagnostics. It is based on methods of non-destructive (without opening tanks and draining dielectric liquids) control of parameters that characterize the state of electrical equipment. We present an original method of diagnosing the on-load tap changer, based on oscillography and subsequent analysis of operation of the on-load tap changer contact system without draining transformer oil from the diverter switch’s tank.