Abstract:

The difficulties and technical requirements of insulation design for single-phase large-capacity main transformer are briefly introduced. Taking the insulation structure of single-phase 410 MVA/220 kV transformer as an example, the double concentric insulation structure is verified. 410 MVA/220 kV transformer is the 220 kV single-phase generator transformer with the largest capacity at present. Due to its large capacity and current, the insulation structure must meet the requirements of electricity, magnetism, heat, force and transportation limit at the same time, which brings difficulties to the design. Through calculation and test verification, the high-low-low-high double concentric insulation structure is adopted, which effectively solves the problems of local overheating and transportation difficulties of large-capacity generator transformers, and can provide reference for insulation design of large-capacity generator transformers for supercritical and ultra-supercritical generator sets. The insulation structure is not only suitable for generators and transformers with 220 kV voltage level, but also suitable for ultra-high voltage and ultra-high voltage transformers with 500 kV and above voltage level.

Key words: Large-capacity, transformer, insulation structure