【摘要】 For AC and DC hybrid transmission lines,the arrangement and transposition modes of AC conductors not only affect the unbalance factor of AC lines,but also influence the bias current of DC converter transformers by AC and DC coupling.Excessive bias current will influence the normal operation of converter transformers,thus the optimal AC phase arrangement and transposition mode of hybrid lines was studied to minimize the coupling effect between AC and DC lines to fit the requirements on both aspects.Based on the parameters of the Ximeng-Shanghai project in China,a detailed simulation model of the DC converter station and the hybrid transmission line with double-circuit AC 500 kV transmission lines and DC ±800 kV transmission lines were presented in the software PSCAD-EMTDC,and the coupling effects of the hybrid transmission lines were elucidated.The fundamental frequency components of DC poles with different operation conditions,arrangements of conductors and operation modes were analyzed,and the effective arrangement and transposition limiting the fundamental frequency current component of the DC line were compared.Simulation results show that AC operating conditions can affect DC induced components while the DC system operation mode has no apparent effect.With compact arrangement and inconsistent transposition of AC lines,the fundamental frequency component on DC lines can be reduced effectively;the three-transposed mode within the hybrid line is the optimal layout scheme,considering both the requirements of DC bias current and AC unbalance degree.更多还原

【Abstract】 For AC and DC hybrid transmission lines,the arrangement and transposition modes of AC conductors not only affect the unbalance factor of AC lines,but also influence the bias current of DC converter transformers by AC and DC coupling.Excessive bias current will influence the normal operation of converter transformers,thus the optimal AC phase arrangement and transposition mode of hybrid lines was studied to minimize the coupling effect between AC and DC lines to fit the requirements on both aspects.Based on the parameters of the Ximeng-Shanghai project in China,a detailed simulation model of the DC converter station and the hybrid transmission line with double-circuit AC 500 kV transmission lines and DC ±800 kV transmission lines were presented in the software PSCAD-EMTDC,and the coupling effects of the hybrid transmission lines were elucidated.The fundamental frequency components of DC poles with different operation conditions,arrangements of conductors and operation modes were analyzed,and the effective arrangement and transposition limiting the fundamental frequency current component of the DC line were compared.Simulation results show that AC operating conditions can affect DC induced components while the DC system operation mode has no apparent effect.With compact arrangement and inconsistent transposition of AC lines,the fundamental frequency component on DC lines can be reduced effectively;the three-transposed mode within the hybrid line is the optimal layout scheme,considering both the requirements of DC bias current and AC unbalance degree.更多还原