Improvement of synchronizing power and damping power by means of SSSC and STATCOM: A comparative study

This paper examines the influence of Static Synchronous Series Compensator (SSSC) and STATic synchronous COMpensator (STATCOM) on the synchronizing power and damping power of a single-machine infinite bus system. The main function of SSSC is to compensate for the voltage drop across the impedance transmission line while the STATCOM provides voltage support at the point of connection at the transmission line. Beside their main function, SSSC and STATCOM can also be used to improve the synchronizing power and damping power, which in turns improve the small signal stability of power systems and thus more power can be transmitted. The SSSC has two modes of operation: (1) constant reactance mode and (2) constant quadrature voltage mode. It was shown that SSSC provides higher synchronizing and damping powers when operated in constant reactance mode than constant quadrature voltage mode. Comparing SSSC with STATCOM, the SSSC, in constant reactance mode, has been found to provide higher synchronizing and damping powers than the STATCOM. However, the STATCOM provides higher synchronizing and damping power than the SSSC when it operates on constant quadrature voltage mode.