Techniques to Compensate the Rapid Variations in Reactive Power and Voltage in Power System

Abstract

In general reactive power demand in power systems is static and dynamic in nature. The newlinestatic demand includes a steady-state load of induction generator/motor excitation requirement, newlineprovided by fixed and switched capacitors while for in case of a dynamic, sudden change in load newlinedemand changes the steady-state condition with new equilibrium state, requires dynamic reactive newlinepower compensation and usually supported by SVC and STATCOM. The cost of SVC with filter newlineand STATCOM is moderate to high, respectively. In this paper, efforts have been made to newlinedevelop a single FACTS device that will take care of static and dynamic reactive power newlinecompensation resulting in voltage sag and swell control with an optimum viable solution. A new newlinetopology with two shunts (FACTS) devices such as thyristor binary switched capacitors (TBSC), newlineand thyristor binary switched reactors (TBSR) have been developed, which are working in newlinecascade. The generalized theory of these devices for n switched capacitor and m switched newlinereactor bank is provided. The VI characteristic for this has also been provided and discussed. A newlinetable of 2n-1 switching states with incremental and cumulative voltages compensated are also newlinegiven. Based on this generalized theory, in few practical cases for different applications, four newlinestepped capacitor and reactor banks for distribution system application are chosen. Especially newlineTBSR bank has been designed, such as having maximum capacity equals to the lowest step of newlineTBSC bank and used as a fine-tuning device, and they are in the closed loop control arrangement newlineis provided. Transient free switching of capacitor and reactor banks are obtained, so that the newlinemajor problem of switching harmonics is eliminated. The simulation results are obtained for newlinedynamic and static reactive power loading conditions for different testing inputs such as step, newlineimpulse with few cycles, and sinusoidal varying dynamic load. With the system identification newlinetoolbox, the mathematical model of TBSC-TBSR has been identified in Matlab simulink. newlineDifferent co