Study on the Shock Wave Characteristics of Natural Esters Using High Voltage Pulse Discharge

With the development of ultra-high voltage (UHV) transmission technology, transformer insulation systems face increasingly severe safety challenges. Natural ester insulating oils, due to their environmental friendliness and high flash point, have become an attractive alternative to mineral oils. However, their shock wave propagation characteristics under extreme electrical stress remain unclear. This study established a comprehensive high-voltage pulse discharge experimental platform. Combining a schlieren imaging system with multi-parameter simultaneous measurement technology, we captured the three stages of high-voltage pulse discharge in oil and investigated the shock wave formation mechanism and attenuation characteristics of soybean and rapeseed-based natural esters. Pin-to-pin discharges were driven by a Marx generator, and shock wave pressure attenuation was quantified using a pressure sensor array. Compared to conventional mineral oils, both natural esters exhibited superior shock wave attenuation, with attenuation coefficients ranging from 1.05 to 1.07 for soybean-based esters and 0.95 to 0.96 for rapeseed-based esters, demonstrating their engineering advantages in suppressing fault shock waves. This study provides key experimental evidence for the safety design and fault protection of natural ester-insulated transformers.