Overheating and discharge fault identification for novel three-element mixed oil-paper insulation system based on new characteristic gas combination parameters

To support the safe operation of the novel three-element mixed insulation oil (TEMO) transformer, gas generation behaviors of the TEMO oil-paper insulation system under overheating faults and discharge faults were investigated. Results show that that the content of H-2 and C2H6 generated by TEMO-paper insulation system is much higher than that in conventional mineral oil (MO)-paper insulation system under different overheating temperatures. Under partial discharge fault, the content of H-2 dissolved in oil changes distinctly, while the content of C2H2 also increases with the discharge time. Under surface flashover breakdown, AC breakdown and lightning impulse breakdown fault, the content of H-2 and C2H2 changes greatly compared to other gases, while the concentration of total hydrocarbon gases in TEMO-paper insulation system is smaller than that in MO-paper insulating system after the same breakdown times. The diagnosis model of overheating and discharge faults for the TEMO-paper insulation system was proposed based on the oil dissolved gas analysis, while H-2, C2H2 and C2H4 were chosen as the characteristic gases and the boundary settings were determined. The verified result for the low-temperature overheating, lightning impulse and surface flashover fault for the TEMO-paper insulation system presents that the new diagnosis model is effective.

Automated summary

Gas generation behaviors of the TEMO oil-paper insulation system under overheating faults and discharge faults were investigated, showing higher content of H-2 and C2H6 compared to conventional mineral oil systems. A diagnosis model based on oil dissolved gas analysis was proposed for the TEMO-paper insulation system, which was proven effective in detecting faults such as low-temperature overheating, lightning impulse and surface flashover.