Operation assessment of an installed ±75 kVAr STATCOM

A static compensator (STATCOM) is a FACTS controller, which can either absorb or deliver reactive power to power systems. A ±75 kVAr STATCOM was installed for a substation in Tehran distribution system. This work demonstrates operation of an installed STATCOM while the imbalance of the substation on the STATCOM behaviour is considered. Different practical results show the quick variations of the capacitor voltage. This is due to an energy oscillation at twice the synchronous frequency between the dc and ac sides. This oscillation also introduces low order harmonics to the inverter output voltages and currents, causing distortion of waveforms along with a poor performance for STATCOM.