Operation of the DC Link in the Conditions of Poor Quality of Grid Power

The HVDC link at the Trans-Baikal Converter Complex at the 220 kV Mogocha Substation operates under conditions of poor quality of power in the grid. Distortions in a grid are characterized by values of the negative-sequence voltage unbalance factor and voltage THD that are many times higher than the rated values. The operation of STATCOMs, which are part of the HVDC link, has a beneficial effect on the quality of power across the 220 kV buses of the Mogocha Substation. However, a STATCOM is additionally loaded by negative-sequence currents and higher-harmonic currents. A mathematical model was developed and calculations were carried out for various modes of operation to estimate the available power output of the HVDC link in conditions of poor quality of grid power.