The 35kV series oil-immersed power transformers are designed with advanced technology, featuring significant improvements in materials, structure, and processes. The high and low voltage clamps are secured using steel tension bands or top and side beams, forming a robust framework structure that enhances the core clamping force and resistance to transportation shocks. They have strong short-circuit resistance, an aesthetically pleasing appearance, reliable operation, low losses, and minimal noise, reaching the advanced level of similar products abroad. The SZ11-8000/35 transformer prototype produced by our company passed the sudden short-circuit test conducted by the national transformer testing center in one go. The longitudinal oil channels in the high and low voltage windings facilitate heat dissipation, significantly reducing the copper-oil temperature difference and the internal winding hot spots.