Abstract: According to the application requirements of high-performance grain-oriented (GO) silicon steel for electical equipments such as power frequency energy saving transformer, medium frequency isolation transformer , and low frequency transformer, the electromagnetic characteristics of 0.10-0.27 mm GO steel under different working frequencies were studied by an arbitrary waveform magnetic field excitation measurement system. Compared with 0.10 mm ultrathin GO steel, 0.18 mm high magnetic induction GO steel has lower core loss in the frequency range of 15-400 Hz. The core loss of 0.18 mm sample is not only lower than that of 0.23 mm and 0.27 mm products in the rolling direction (RD), but also has the advantage of minimum loss in the transverse direction (TD). However, for materials with the same thickness, low loss in RD does not mean low loss in TD. The differences of electromagnetic characteristics of silicon steel with different thickness were analyzed, and the results can support the core materials selection of different types of transformer. Finally, the future development trend of thin-gauge GO steel was prospected in terms of the performance requirements of core materials for power frequency, medium frequency and low frequency electical equipments. 

Key words: power equipment, grain-oriented silicon steel, medium and low frequency, electromagnetic characteristics