Transient Electromagnetic Thermal Effects of a Test Transformer Under the Influence of Extreme Geomagnetic Induction Currents
摘要
Extreme geomagnetic induction currents (GIC) are pulsed currents with durations ranging from several seconds to several minutes. In extreme cases, their amplitudes can reach hundreds of amperes. To study their short-term effects on transformers, this paper uses a single-phase three-column transformer as an example to establish a 3D electromagnetic and thermal finite element method (FEM) calculation. The results of calculating transformer effect data under the influence of short-term GIC show that when subjected to a 200 A pulse GIC, the hot spot temperature (HST) of the transformer winding can reach 173 °C, exceeding the temperature rise limit specified by the IEC 60076-7, which will jeopardize the safe operation of the transformer.