CALCULATION OF THE GEOMAGNETIC INDUCED CURRENTS IMPACT ON THE HIGH-POWER TRANSFORMER

• Main Authors: V. F. Ivankov, A. V. Basova
• Format: Article
• Language: English
• Published: Zaporozhye National Technical University 2019-12-01
• Series: Elektrotehnìka ta Elektroenergetika
• Subjects: transformers; geomagnetic induced currents; losses; temperature rises; calculations
• Online Access: http://ee.zntu.edu.ua/article/view/198835

Purpose. Determination of resistance of a powerful power transformer to the action of geomagnetic induced currents (GIC) and structural measures for its increase, if necessary. Methodology. An analytical calculation of the magnetization current (MC) is applied, which under the action of geomagnetic induced currents is excited in addition to the rated current in the higher voltage winding. Analytical and numerical calculations of the magnetic field and the losses, and computational-empirical methods for estimation of the temperature rises are used. Findings. For a five-core transformer with a power of 630 MVA under the GIC effect, the increased losses and heating of structural elements on the cores of the magnetic system, the tank, and the increased sound level are determined. Originality. For the case of orthogonal property of the vectors of winding rated currents and the vectors of harmonic components of the peak unbalanced MC, the Joule losses are represented by the sum of the losses due to these currents using the increase factors for ohmic losses in non-magnetic and ferromagnetic structural parts, which depend on MC harmonic spectrum. Practical value.  The stability of the transformer under test to the given level of GIS was confirmed, and structural measures for its increase were recommended. The tested methods can be used in the computational design, in the study of real cases of equipment operation.