DESIGN OF DAMPING CONTROLLER FOR CSI STATCOM

Abstract

For reliable service, a power system must remain intact and be capable of withstanding a wide variety of disturbances. Therefore, it is essential that the system should be designed with proper precautions so that it can tolerate the more probable as well as most adverse contingencies. As, we know the - stability problem involves the rotor angle oscillations which is natural in power systems. If the oscillations are severe one, the synchronous machine may out of step from the rest of the system. This thesis work deals with a power system installed with a current source inverter based static synchronous compensator and demonstrates its effectiveness in damping out the rotor oscillations. A Phillip-Heffron model of single machine infinite bus power system installed with a CSI STATCOM was developed which is actually a linearization around the operating point. This model acts as the basis for a state feedback controller which actually gives us a way to place the closed system poles at the most suitable place. The whole work was done in MATLAB package and the results show a very nice damped system. Finally a practical CSI STATCOM was simulated in PSCAD/EMTDC package to find out it capabilities with active as well as passive filters both. Switching scheme adopted was tri logic pulse width modulation scheme. It was found that CSI STATCOM installed with the passive filter in a small size power system gives the required results but an active filter in a large size power system need some further modification