Analytical efficiency evaluation of two and three level VSC-HVDC transmission links

An analytical method to calculate the efficiency of VSC-HVDC links based on two-level and three-level VSCs is presented. The method uses the average and root mean square of the VSC converter current to estimate the conversion losses in the converters (conduction and switching losses). The remaining power losses (DC cable transmission losses due to I2R, the losses in the coupling transformer, and AC harmonic filter losses) are evaluated using conventional well-known methods. Results obtained analytically are confirmed by digital simulations.

► Analytical equations derived to evaluate efficiency of two and three-level VSC-HVDC.
► Losses comparison between two and three level VSC-HVDC is carried out.
► Software program used to validate the result obtained with the analytical method.
► Losses calculation is important to optimize system performance of VSC-HVDC.