Study On Radio Interference Of Corona Discharge From UHV AC Transmission Lines Based On Excitation Function Method

In recent years,China has created new world records in the field of Ultra High Voltage(UHV)transmission,which consolidate our country's leading edge in this field all over the world.The electromagnetic intensity around the UHV transmission lines is much higher than those of high voltage(HV)and extra-high voltage(EHV)transmission lines.Then the problem of the electromagnetic environment caused by the UHV transmission lines has been attracted attention widely and restricted the development of the UHV technology.In the construction of the UHV transmissions,the parameters of electromagnetic environment,especially the interference caused by corona discharge should be considered.According to the generation mechanism and basic properties of the radio interference,research models for specific lines are established.Then,the evaluation prediction and influence factors of the radio interference are studied by the Matlab software platform.Our results are of great significance for improving the problems of electromagnetic environment and the mental health of human.Firstly,the generation mechanism,properties and excitation function theory of radio interference are elaborated in detail.Secondly,the advantages and disadvantages of several calculation methods of conductor surface gradient are discussed.It shows that the optimization introduced in this thesis is more accurate than other methods and the influence factors of conductor surface gradient are analyzed.Thirdly,a typical simulation used by a new excitation function,which is more suitable for the national conditions in our country,is performed by the Matlab software platform.After comparing with the measured data from UHV AC pilot project,it shows that the model and simulation in this thesis are reliable.As the sag of line is the important influence factor of the radio interference,a three-dimensional model with the sag is established based on the two-dimensional model and the evaluation of radio interference along the transmission line is also analyzed by the simulations.Finally,the effects of radio interference on the UHV transmission lines are analyzed from the following three aspects: the line structure,the environmental conditions and the human factors.And the corresponding solutions to weaken the interference are also discussed in the thesis,which are helpful for the accurate prediction of the radio interference on the UHV AC line project.