The aim of this paper is to present experimental results on the short-circuit and load test of the single-phase transformer at low frequencies. The paper gives information on PC based measurement setup and presents the results of measurement of primary and secondary voltages and currents and electric power of the transformer. Also, a proper discussion of the results obtained is given in the paper
Słowa kluczowe: power transformer, short-circuit test, load operation, power loss.
W artykule przedstawiono rezultaty badania zwarcia I obciążenia jednofazowego transformatora niskoczęstotliwościowego. Przedstawiono system komputerowy do badań i rezultaty pomiarów prądów I napięć w obwodzie pierwotnym I wtórnym.
Keywords: transformator jednofazowy, badania, zwarcie.
Previous research on the operation of a single-phase power transformer at low frequencies was conducted under no-load conditions . It was found that primary current of the transformer increases with the decrease of the frequency (at constant amplitude of primary voltage). Also, this current becomes significantly distorted from the sinusoidal shape, which indicates increase of the magnetic flux density in the transformer core and approaching to the magnetic saturation . The aim of this paper is to present results of continuation of research on the operation of the transformer at low frequencies in the case of short-circuit or load conditions. General requirements on such testing are given in the international standard . Short overview of these tests exists in the literature [4, 5]. The results of the short-circuit and load test of power transformer at low frequencies are presents in this paper. The transformer under study is a single-phase unit, rated at 1 kVA, 230 V/12 V, 50 Hz. It has an EI core. Tests are performed at different frequencies from 1 Hz to 50 Hz. The amplitude of secondary current has been maintained at 100 A during the short-circuit test and the amplitude of primary voltage has been maintained at 25 V during the load test. PC based measurement setup is used to record time waveforms of primary and secondary voltages and currents. The input power is also recorded during the tests. The paper presents experimental results obtained and gives their discussion. Standard requirements on short-circuit and load test for transformers The International Electrotechnical Commission (IEC) publishes relevant standards for power transformers. Published standards are related to electrical and other bonding technologies. IEC members are National committees for electrotechnics from participant countries. Technical Committees (TC) play the main role in the preparation of standards, gathering more than 10 000 experts [...]
 Koprivica B., Milunovic Koprivica S., No-Load Operation of Single-Phase Power Transformer at Low Frequencies, International Scientific Conference - UNITECH 2017, Gabrovo, Bulgaria, 2017, Vol. 1, pp. I-75 - I-79  Langella R., Testa A., Emanuel A.E., On the Effects of Subsynchronous Interharmonic Voltages on Power Transformers: Single Phase Units, IEEE Transactions on Power Delivery, 23 (2008), No. 4, 2480 - 2487  IEC 60076-1 Edition 3.0, 2011-04, Power transformers - Part 1: General, IEC, Geneva, Switzerland, 2011  Winders, Jr. J.J., Power Transformers - Principles and Applications, Marcel Dekker, NY, USA, 2002  Harlow J.H., Electric Power Transformer Engineering, CRC Press, Boca Raton, FL, USA, 2004