The Application Study Of FDTD Method To Simulate Of Electromagnetic Field Around EHV Transmission Line

As the main artery of power network, the extra high voltage (EHV) transmission line generates powerful electromagnetic field and electromagnetic radiation in the space, which pollutes the electromagnetic environment seriously. This problem has got every walk of life's attention all over the world. So it is important theory value and realistic significance to simulate, calculate and analyse the electromagnetic field around the EHV transmission line and to evaluate whether it satisfies the relevant environmental protection standard, which provides the basis for taking necessary countermeasures.At first, the Finite-Difference Time-Domain(FDTD)method's fundamental principle is introduced. Then some key technologies using FDTD method to solve the electromagnetic scattering problem are expatiated. Based on the algorithm thinking of the FDTD method, general algorithm program on electromagnetic scattering problem is given. Its validity is tested and verify by comparison.Based on the passive radio disturbance mechanism of the EHV transmission line, the EHV transmission line's passive radio disturbance calculating model (corresponding to the steady electromagnetic scattering problem) is established, which enlarges the FDTD method to simulate the electromagnetic field around the EHV transmission line. Under the radio single irradiating, different incident angle and different arrange way, either there is lightning conductor or not, the electromagnetic field distributing conditions around the EHV transmission line is calculated and lots of numerical calculating result is obtained. Moreover, the field intensity plane distribution figures are given and the distributing conditions are analyzed a certain extent.Based on the different conditions of the lightning strikes the EHV transmission line, the calculating models, when the EHV transmission line is suffering the direct lightning stroke and. the induced lightning stroke, are established and different algorithm programs corresponding to different calculating models are also given, which enlarge the FDTD method to simulate the radiating field problem of the EHV transmission line. The induced lightning stroke of the EHV transmission line and the radiating field generated by the lightning surge wave propagating along the EHV transmission line are both calculated and the respective response conditions are also analyzed and illuminated.To sum up, applying FDTD method to simulating the electromagnetic field aroundthe EHV transmission line is feasible. Some valuable results has been obtained, and the FDTD method's applied range has been extended.