To insure faultless and profitable operation of the electrical transmission and distribution network, it is necessary to monitor the condition of the equipments, especially high voltage transformers. Because of the complex structure of the power transformers, the evaluation of the data and determine the optimal rate of maintenance is a difficult task. The Transformer Status Indicator (TSI) provides an efficient way to deal with this problem.
The first part of the thesis reviews the stress of the transformers under power, and their impact on the condition of the equipment. It also enumerates the most commonly used methods in diagnostics, and how the results are evaluated in the TSI system.
The main topic of my study is presenting the results of the test of the TSI decision supporting expert system developed at the University of Technology and Economics, Department of Electric Power Engineering. I give details of the test method, and summarize the possible future developments based on the experiences.