Calculation of electrodynamic forces acting on clamping beams of windings in 500kV power transformers with ratings up to 300MVA

Abstract

In response to the growing demand for electrical load driven by socio-economic development, the national transmission grid is being gradually upgraded. In this context, conventional 500 kV transformer units with capacities of 3×150 MVA and 3×200 MVA are increasingly being replaced by higher-capacity units, most notably the 3×300 MVA transformers. To meet this trend and reduce dependence on imported equipment, the research, design, and manufacturing of 500 kV–3×300 MVA power transformer units present a significant technological challenge for the domestic industry and remain a current topic of interest among both national and international researchers. During operation, short-circuit events subject the windings to extremely high electrodynamic forces, posing a risk of severe deformation or insulation failure if not properly designed. In the winding structure, the clamping beam plays a critical role in directly withstanding these forces, preserving the mechanical integrity of the winding, and maintaining insulation stability throughout operation. This paper develops an analytical approach combined with the finite element method (FEM) to compute, analyze, and simulate the electrodynamic forces acting on the clamping beam in 500 kV ultra-high voltage transformers with power ratings up to 300 MVA under various operating conditions. Accurate assessment of the mechanical behavior during short-circuit events is essential to ensure the structural integrity and safe operation of the equipment. The study integrates both analytical and FEM techniques to evaluate stress and deformation in the clamping beam across different scenarios.