Versatile Control of STATCOMs Using Multiple Reference Frames

This chapter first reviews the fundamentals of active and reactive power control using STATCOMs. Then, two current control algorithms, namely selective/resonant controllers and repetitive controllers, are presented that provide a STATCOM with the capability of controlling the harmonics of the current injected into the PCC. Finally, the use of synchronously-rotating reference frames is generalized so that current harmonic control can also be achieved using PI controllers. An efficient application of the last technique is explained in detailed and a number of experimental results are presented. It will be demonstrated that versatile control of STATCOMs is straightforward using this technique even if the grid frequency varies. This technique can be applicable to both, traditional, strong and centralised electric power systems and those to come in the future with large amounts of distributed generation.