Electromagnetic Field Simulation Of Transformer External Short Circuit Based On Finite Element Method

As the key component of the power system,the safe operation of the transformer is of great significance to the stability of the power system.Short circuit acts as a major threat to transformer operation.When the short-circuit fault occurs,the transformer is the most affected electrical equipment with short circuit impact,and it faces huge security risks.Therefore,it is of great significance to study the short-circuit problem.This paper introduces the background and significance of large power transformer winding short circuit calculation,discusses the research status of the transformer leakage magnetic field and short circuit electric power and other issues at home and abroad,and then combined with the transformer structure parameters of a Guangdong Grid Co to carry out short circuit test three-phase five pole,creating the 3D simulation model of the proportional transformerin the ANSYS Maxwell software.The field circuit coupling theory is adopted to simulate excitation,and the single-phase external short circuit process of the transformer A phase and B phase is simulated.Different from the past,the short circuit current is obtained by the circuit simulation software,and then the short-circuit current is simulated as a finite element method to stimulate loading.The field circuit coupling is more in line with the practical working principle of the transformer,so the simulation results are more reliable.In this paper,the total short-circuit time of transformer short circuit simulation is 250 ms.In order to make the simulation take into account the calculation accuracy and efficiency,the simulation time step is selected as 2.5ms.By comparing the short-circuit current fortest obtained with simulation obtained,analyzes two main parameters of instantaneous short-circuit current peak and short-circuit current value,verify the correctness of the calculation method of field coupling circuits.At the same time,induction potential of non shorted phase winding,the magnetic flux density of the core,the leakage magnetic field and the force of the winding are obtained.The physical quantities such as non short circuit phase winding,induction potential of non shorted phase winding,magnetic flux density,leakage magnetic field and winding force are analyzed theoretically,and all of them are of high accuracy.So as to provide a reliable data basement for further studying the external short-circuit of transformer,such as the winding stability in short-circuit process and the surge of oil flow caused by short circuit.