An Investigation Of The STATCOM-SMES In Damping Low Frequency Oscillations In Power Systems

SMES combined compensator on damping power systems low frequency oscillations and eliminating the fluctuations of the voltage at the point of the fault, finally the impacts of STATCOM-SMES combined compensator installed to different locations on This paper discusses the performance of a voltage source inverter-based static synchronous compensator (STATCOM) in damping low frequency oscillations in power systems by introducing a superconducting magnetic energy storage (SMES) coil, and the impacts of the STATCOM-SMES combined compensator on system dynamics resulting from three-phase short circuit are investigated in detailed.The SMES coil is attached to the voltage source inverter front end of the STATCOM via a two-quadrant three-phase dc-dc chopper, and the STATCOM is connected to a one-machine infinite bus system by a coupling transformer. The power system dynamic oscillations are simulated with no-load,a metallic fault and with load,a short circuit through impedance, and the effects of the STATCOM-only are compared with STATCOM-system dynamics are compared.In the paper, the dynamic responses of power systems with different loads to a three-phase fault are studied using an electromagnetic transient program PSCAD/EMTDC, and the findings are presented.The results show that,the STATCOM-SMES can absorb or inject active and reactive power simultaneously and it can effectively damp power systems dynamic oscillations and greatly inhibit fluctuations of the voltage with the addition of energy storage. Especially, when the combined compensator is connected to the source end, a STATCOM-SMES with real and reactive power capability can more effectively improve system static and dynamic stability, and enhance the reliability of a transmission grid.