Algorithms Used for D-STATCOM to Achieve Compensation Current Detection

Abstract

Now a day’s power electronic based equipments are used in industrial and domestic purpose. Passive filter has been used traditionally for mitigating the distortion due to harmonic current in industrial power systems. But they have many drawbacks such as resonance problem, dependency of their performance on the system impedance etc. To overcome of such problem active power filters is introduced. It has no such drawbacks like passive filter. They inject harmonic voltage or current with appropriate magnitudes and phase angle into the system and cancel harmonics of nonlinear loads. But it has also some drawbacks like high initial cost and high-power losses due to which it limits there wide application, especially with high power rating system. Classically, shunt passive filters, consist of tuned LC filters and/or high passive filters are used to suppress the harmonics and power capacitors are employed to improve the power factor. But they have the limitations of fixed compensation, large size and can also exile resonance conditions. Active power filters are now seen as a viable alternative over the classical passive filters, to compensate harmonics and reactive power requirement of the non-linear loads. The objective of the active filtering is to solve these problems by combining with a much-reduced rating of the necessary passive components. The performance of D-STATCOM as a compensator depends on the control algorithm This paper mainly studies the algorithms used for D-STATCOM in order to achieve compensation current detection, harmonic elimination and reactive power compensation during unbalance loading conditions in distribution system.