Modeling and Simulation of a STATCOM for reactive power control

Reliable and efficient power systems operation requires voltage control as well as minimal reactive power flow between a load and the grid. To achieve this objective, reactive power compensating devices are typically utilized. In modern power systems, the synchronous static compensator (STATCOM) is primarily used for reactive power control, both in distribution and transmission lines. This study presents the modeling and simulation of a STATCOM based on a voltage source converter. Simulations are performed for both single phase and three phase power systems. Furthermore, two control techniques, utilizing Proportional Integral (PI) as well as Proportional Resonant (PR) controllers are explored. The PR controller presents several advantages compared to the PI controller. Simulation results show that in both cases, the STATCOM, connected in shunt with the load either provides reactive power to the load, or absorbs reactive power from the load. Thus, net reactive power transfer from the grid to the load is zero. The grid provides only active power, thus keeping the power factor to almost unity.