Device for Assessing Working Resource Consumption of Power Oil Transformer Windings

Abstract

A power transformer is one of the most responsible and expensive assets in power systems and networks. Failure of a power transformer can lead not only to downtime of the entire electricity transmission path, but also to danger to personnel and the environment. One of the main reasons for the failure of a power transformer is the deterioration of the insulation of the windings. The insulation of the transformer windings is affected by many different factors, but one of the main factors is the effect of temperature due to the different values of the currents flowing through the transformer windings.

The power transformer is exposed to the effects of long-term and short-term loads. There are known methods and tools that allow you to assess the technical condition under long-term loads. In the literature, less attention is paid to the issue of the influence of short-term loads, although their influence on the thermal aging of the winding insulation is obvious. The author has developed a method and a mathematical model that allows to estimate the thermal effect on the insulation of the windings regardless of the duration of such an effect. The essence of the method is based on the determination of the amount of heat that is released when the current flows through the windings with the subsequent heat spread over the windings and structural elements of the transformer, which allows you to build a temperature distribution surface from the point of heat release.

The paper proposes the structure of the device for estimating the residual working life of the insulation of the power transformer, which is based on the basis of the developed mathematical model. The article describes the implementation of this approach in detail.

It is important to add that the proposed method does not require significant capital investments and meets the requirements of accuracy and reliability.

The developed tool can be recommended for use by energy companies in the tasks of diagnosing power oil transformers, which can be integrated into the monitoring system of all electrical equipment of the distribution device of a power plant or substation, which allows to reduce in a certain way the costs of maintenance of electrical equipment.