The 35kV series power transformers are designed with advanced technology, featuring significant improvements in materials, structure, and processes. High and low voltage clamps are secured with steel tension bands or upper and side beams, forming a robust framework structure that enhances core clamping force and resistance to transportation shocks. They boast strong short-circuit resistance, an aesthetically pleasing appearance, reliable operation, low losses, and minimal noise, reaching the advanced level of similar foreign products. The SZ13-20000/35 transformer prototype produced by our company passed the sudden short-circuit test conducted by the National Transformer Testing Center on the first attempt. The longitudinal oil channels in the high and low voltage windings facilitate heat dissipation, significantly reducing copper-oil temperature differences and the rise in internal winding hot spots.