Analysis Of Coupling Characteristics Of Corona Current From DC Conductor Parallel With AC Conductor

With the rapid development of economy in China,the HVAC and HVDC transmission lines set paralleded can provide an effective way for increasing the transmission capability of existing corridor.However,the discharge characteristics of conductors are more complex with the structure of hybrid AC/DC conductors compared with only DC conductors.Based on the method of experimental measurement,the coupling characteristics of corona current with the structure of hybrid AC/DC conductors are analyzed,and the results can lay a foundation for the study of audible noise and radio interference.Firstly,the test platform of hybrid AC/DC conductors is set up in the laboratory,and it is found that the corona voltage of positive DC conductor decreases linearly with the increase of AC voltage.Based on the characteristics of positive corona current pulses measured under different AC voltages,the influence of the approaching distance between AC and DC conductors and AC voltage on the statistical characteristics of positive corona current pulse parameters are analyzed.The experimental results show that with the increase of AC voltage,positive DC corona current pulses gradually distribute in the form of pulse clusters.In this paper,the characteristics of DC corona discharge of AC conductor are analyzed from the perspective of space charge and space electric field,and the coupling effect of AC voltage on the corona discharge of DC conductor under the condition is theoretically analyzed.Secondly,based on the high potential experimental platform,the effects of AC voltage on the characteristics of negative corona current pulses under parallel AC and DC conductors are obtained.The effects of AC voltage and approaching distance on the parameters of negative corona current pulses are obtained through anlayzing the waveform parameters.In order to analyze the influence of AC voltage on DC corona current pulse,this paper compares and analyses the difference between positive and negative DC conductors in terms of the generation mechanism.The influence of AC voltage on the corona discharge of negative DC conductor is analyzed by calculating the ionization energy density of negative DC conductor under different AC voltages and different approaching distances,and the influence mechanism of AC voltage on the parameters of negative DC corona current pulse is analyzed.Finally,the influence of DC voltage on corona discharge of AC conductor under parallel AC and DC conductors is analyzed.The AC corona current pulses under different structures are measured based on high potential measurement system,and the characteristics of AC corona current pulses parameters are also analyzed.The influence mechanism of DC voltage on discharge characteristics of AC conductors is analyzed by calculating the average ionization energy density of AC conductors.