Influence of inductive filtering method on harmonic transfer characteristic of HVDC transmission system

A new HVDC transmission system based on an inductive filtering method is presented in this paper, and then a unified equivalent circuit model and mathematical model are proposed for the calculation on the harmonic transfer characteristic of the new HVDC systems. Firstly, according to the topology of the new HVDC converter station, the equivalent circuit model, which is expressed by the fundamental and the harmonic impedance, is established. Secondly, the harmonic transfer model, which can be used to reflect the effect of inductive filtering method on the harmonic distribution characteristic of the new HVDC transmission, is established through the detail mathematical derivation. Then, by the theoretical analysis on the commutation process of the converter, the time-domain expression of the valve current is obtained to express the harmonic characteristic of the converter. Finally, through the detail theoretical calculation, system simulation and physical experiment, it validates the established mathematical model, and further reveals the harmonic transfer characteristic of the new HVDC transmission system based on the inductive filtering method.