Research Progress on Electrical Insulation Under Superimposed Voltage With High‐Frequency Harmonics in New‐Type Power Systems

ABSTRACT A new‐type power system serves as a critical technical support for the integration of new energy, and its secure and stable operation is of great importance. However, the extensive utilisation of power electronic devices leads to power equipment insulation being subjected to electrical stresses of high‐frequency harmonics, which can easily cause insulation degradation or even failure. Therefore, a comprehensive understanding of the insulation failure characteristics, mechanisms and performance enhancement methods for typical power equipment in the new‐type power system under high‐frequency harmonic conditions is essential for improving equipment reliability. This paper focuses on the research progress in insulation of key power equipment in the new‐type power system, such as converter transformers, converter valves, solid‐state transformers and dry bushings. It systematically summarises the complex operational stresses and insulation failure characteristics experienced by concerned equipment, analyses the underlying failure mechanisms, reviews existing primary performance improvement approaches and provides suggestions for future research. The findings of this study offer theoretical and experimental support for ensuring the robust construction of the new‐type power system under high‐frequency harmonic conditions.