Study of hybrid dstatcom topology for mitigation of harmonics in distribution system

Abstract

The power system network has been spread over a wide area and usage of non-linear load has also been increased. Due to these reasons, the distribution system is subjected to various power quality issues. These power quality issues are the reactive power burden, harmonic currents, load unbalance, excessive neutral current etc. This article proposes a Hybrid DSTATCOM topology connected to a distribution system with non-linear load for mitigation of harmonics. The performance of Hybrid DSTATCOM has been compared with traditional DSTATCOM and Electric Spring. In hybrid topology, an LCL filter is connected in the front of VSI which gives better switching harmonic elimination using a smaller value of inductor as compared to the traditional L-filter. LCL-filter is connected with a series capacitor to reduce the voltage across the capacitor which is connected in parallel to VSI, it is called dc-link voltage, therefore reduction of power loss, reduction of VSI rating and reduction of voltage across the LCL-filter. An Electric Spring with a harmonic compensation function has the capability of harmonics compensation by the load by producing anti-harmonics and also a capability of critical load voltage regulation which makes it to the nominal value. The performances of Hybrid DSTATCOM topology and Electric Spring for harmonic mitigation are investigated using simulation and compared with traditional topology.