TCSC and PSS Design Using Genetic Algorithm Modal Optimal Control

The power system is subjected to different types of disturbances such as small changes in the load thataffects its efficiency and sometimes leads to unstable system. These disturbances cause oscillations at lowfrequencies that are undesirable since it affects the amount of transferred power through the transmission linesand leads to external stress to the mechanical shaft. In order to compress low-frequency oscillations, a commonsolution is use the power system stabilizer (PSS). This paper presents the coordination of PSS and POD in aSMIB power system equipped with TCSC. Some effective controller using PSS and POD schemes wereproposed to improve power system stability. These controllers produced supplementary signals, the PSS outputsignal for machine and the POD’s for TCSC. A two stage lead lag compensator scheme was considered in thePSS structure. A new controller design, linear optimal control associated with modal control schemes, isproposed in both PSS and POD design. By selecting the weighting matrix Q in conjunction with the close looppole shifting, the proposed modal optimal control has been formulated. The GA method was used to determinethe parameter controllers for both PSS and POD. The dynamic and stability of power system with proposedcontrollers was investigated by using small disturbance to power system, 20% load variation. Simulationresults show that the presence of TCSC in power system network provided by PSS and POD controller is verypotential to improve system stability. A 45% of overshoot reduction could be reached, it is obtainedsignificantly settling time shorter, although the MO POD shorter only 16% than PSS ones. The dominanteigenvalues shift to the more stable area, the real part of new eigenvalues approach their threshold -0.1. Thisresult indicates that the proposed modal optimal control has a good performance. Simulation results alsorevealed that the role of POD controller is more dominant than the PSS, however both PSS and TCSC PODcontroller simultaneously present a positive interaction.

کلیدواژه ها:

GA ، modal optimal control ، power system stability ، SMIB ، TCSC ، PSS