Electric Power Research Institute,State Grid Anhui Electric Power Company Limited,
Transformer has always been an important equipment in the power grid. Any failure of such key equipment will seriously affect the reliability and stability of the power system. As the main protection method of transformer, the reliability of gas protection action has always been concerned. In recent years, the accident of misoperation of gas protection under the impact of external short circuit occurs frequently, which seriously threatens the operation efficiency of transformer. In order to explore the characteristics of oil flow in the pipeline when the external short-circuit fault occurs, this paper establishes a transient oil flow measurement system on the power transformer and carries out the external short-circuit fault test. The test results show that the transformer winding deformation and vibration caused by short-circuit current will lead to oil flowing through the pipeline. Due to the inertia of the liquid, the time delay of the oil flow measured in this paper can reach hundreds of milliseconds. In actual operation, the time of misoperation of gas protection lags behind the external fault for hundreds of milliseconds, which is consistent with the delay phenomenon of oil flow action. The test also shows that the severity and location of the fault will affect the oil flow surge. Finally, the results of oil flow action delay given in this paper can provide an important reference for further study on the mechanism of oil flow shock and misoperation of gas protection.