Impact of relationship between inverter and rectifier strength to HVDC transmission capability

This paper analyzed the running characteristics of rectifier and inverter, studied the operating characteristic curves of DC sending end and receiving end connected with AC system of different intensity. The ratio of rectifier SCR and inverter SCR is defined as SCR Ratio, which is called as SR in this paper. It firstly studied the power curves of rectifier and inverter and obtained the quantitative relationship between converter station maximum transmission power and SCR of both sides respectively, then contrasted SCR of DC sending end and receiving end with the same maximum transmission power, and ratio of the two SCR is defined as Critical SCR Ratio, which is known as CSR. Besides, the value of CSR is obtained as 0.94 through theoretical research combined with a large number of simulation analysis. The maximum transmission power is limited by inverter when SR is less than CSR and vice versa. Finally, this paper pointed out that both sending end and receiving end can affect the transmission power limit of HVDC. When SR of HVDC is given, transmission capability is limited by the particular side. The correctness of all the conclusions is verified by the actual system simulation on PSCAD.