Improved Switching Technique for VAR Compensator Considering Minimum Harmonic Injection
SVC is FACTs (Flexible Ac Transmission Systems) device used to control the reactive power and thereby improving the voltage regulation and power factor. The components used in SVC are Switched Capacitors and controlled reactors. Static Var Compensator (SVC) produces a significant harmonics due to the switching of reactors in order to control the reactive power. The addition of switched capacitors will result in the leading current and hence an improved power factor. The rectors are inserted in the system for limiting the voltage rise on a lightly loaded transmission lines. The rectors are connected in series with a bidirectional valves. The reactive power control through inserting reactor is achieved by adjusting the conduction angles of the bidirectional valve in order to control the voltage across the reactor.
A Selective Harmonic Elimination (SHE) based technique for switching reactors in conjunction with Binary Switched Capacitors (BSC) is used for the SVC model to eliminate the significant lower order harmonics. The performance of the proposed topology is simulated in MATLAB/Simulink environment and it considerably improves source current THD compared to conventional switching without using additional filters.
Keywords - Static Var Compensator (SVC), Selective Harmonic Elimination (SHE), Binary Switched Capacitors (BSC)