Response of D-STATCOM under unbalanced voltage condition caused by SLG fault

This work presents a study on a distribution static compensator (D-STATCOM) operating in electrical systems where the voltages are unbalanced due to SLG fault. During the SLG fault, negative sequence components exist in the system. In balanced systems the STATCOM has a very good performance, allowing compensation of capacitive or inductive reactive power with a fast transient response. When there are negative sequence components due to voltage imbalance, the D-STATCOM has reacted in reducing the unbalanced in the system. An analytical analysis, and simulations of a 12-pulse D-STATCOM using the electromagnetic transient program (PSCAD/EMTDC) show how D-STATCOM reacts during the unbalanced in the system affected by negative sequence components and how its performance increase the power system's stability. The D-STATCOM performances under unbalanced voltage are illustrated in the paper along with harmonics analysis study.