PC-Controlled Temperature-Rise Test of Power Transformers
Zdenko Godec · 2001
Temperature-rise test is the most complex and time-consuming factory test of transformers. It consists of several measurements that have to be performed in sequence. First, it is necessary to measure winding(s) dc resistance at a known temperature. Then the transformer should be heated with ac supply up to oil steady-state temperature rise. At the same time ac voltages, currents, powers, frequency and temperatures should be measured. Since the temperature rise of windings is determined from dc resistance increase, the winding(s) resistance should be measured again at the end of the heating. The paper presents reasons for development of computer programme for automation of: test engineer guidance, measurements, recording, storage, data processing and test report creation. It also describes management of the project and how hardware and software are selected. Test automation has decreased test costs, increased transformer test station capacity, increased accuracy and reliability of measurement results, and made easier the work of test engineer. With LabVIEW it is possible to develop applications for complex measuring processes. LabVIEW simplifies programming, and it is fun to work with it, but it is large, complicated and does not yet attain the level of user friendliness that would satisfy the needs of test engineers in test stations.