Design and installation of a ±250 kVAr D-STATCOM for a distribution substation

A Static Compensator (STATCOM) is a flexible ac transmission system (FACTS) controller, which can either absorb or deliver reactive power to a power system. This technology has resulted in an equipment that is principally different from conventional static VAr compensators (SVC). The steady-state characteristics of a STATCOM are similar to those of a rotating synchronous condenser. A ±250 kVAr D-STATCOM was designed and installed for a 1.6 MVA distribution substation in Tehran, which is the first installation of this type in Iran. The principal aim of this installation is reactive power control for voltage regulation, with a particular work on reduction of unbalance issue. This paper describes the design and operating fundamentals and characteristics of a D-STATCOM as well as its basic control strategy. Moreover, different practical results demonstrate the flexible operation of the employed equipment.