*2.5. D-STATCOM*

The D-STATCOM is commonly regarded as a shunt compensator which supplies reactive power in PFAs. The voltage magnitude at the D-STATCOM bus can be controlled by adjusting the reactive power injection of D-STATCOM.

The interface of the D-STATCOM at ith bus shown in Figure 2a, and its traditional modelling for PFAs is shown in Figure 2b. The specified reactive power of the load is combined with the reactive power output of D-STATCOM, so that reactive power varies as magnitude of V<sup>i</sup> varies. This is absolutely a PV bus modelling with the real power output of the D-STATCOM set to zero [27,28]. The hypothesis in this model is that losses in the D-STATCOM and its connection are ignored. The D-STATCOMs have low harmonic content, so the harmonic current injected by the D-STATCOM is considered as zero for HPFA.

**Figure 2.** (**a**) D-STATCOM interface at ith bus 2 (**b**) Traditional modelling of D-STATCOM as PV bus.
