Abstract: Introduction to the ZX2 gas insulated double busbar combined voltage transformer cabinet structure of 35 kV substation and the operation mode before the accident. Field description of busbar voltage transformer cabinet in section E of 35 kV substation, analysis of the cause of voltage transformer collapse, analysis of voltage parameter change of 220 kV and 35 kV during collapse, analysis of on-site damage of voltage transformer cabinet, and the breakdown of voltage transformer cabinets one by one. Each part of the equipment was dissected and analyzed, and the specific reasons for the explosion accident of the busbar voltage transformer cabinet I of the 35 kV substation E section bus voltage transformer cabinet I collapsed and damaged the cabinet body were found. Based on the analysis results of the breakdown of voltage transformers and transformers in the E section of the 35 kV substation and the existing defects, preventive measures and optimization upgrades were proposed to completely solve the faults and defects of the voltage transformer cabinets, which solved the defects of similar 35 kV voltage transformer switch cabinets. The prevention of accidents provides a reliable reference, and also provides applicable examples for the upgrading and transformation of similar equipment, prolongs and guarantees the service life of similar equipment, maximizes the benefi ts of similar equipment, and saves a lot of investment.