In order to study the coupling interference of magnetic storms on high voltage transmission line and its effect on electromagnetic transient of power system

we established a coupling model of space time-varying magnetic field and transmission line

and analyzed the coupling interference relationship between magnetic storms and power lines in the form of field. In addition

we used different DC power supplies to simulate the electromagnetic transient disturbance from magnetic storm for the 500 k V power transmission system

and calculated its effect on power system in the form of circuit. The results indicate that the coupling current in transmission line is varied uniformly with the magnetic storm changing. When the change rate of magnetic field is 1.6 n T/s

the maximum coupling current of 500 k V single transmission line can be more than 2.4 A. Moreover

the magnetic storm has significant effects on the electromagnetic transient

when the magnetically induced current in the power grid caused by magnetic storm reaches 80 A

the growth of three-phase braking overvoltage is beyond 10%

and the offset of the initial secondary arc current is more than 50 A

which should be paid attention to.