A Distributed Filtering-Based Comprehensive Framework to Optimize Grid Performance of Harmonic-Polluted Distribution Systems

With the projected penetration levels of distributed generators (DGs) and electric vehicles (EVs) charging load, the power quality of the utility grid will significantly deteriorate, resulting in grid pollution and many non-compliant nodes. Addressing this issue with the conventional load-side filtering-based solution will be uneconomical. Thus, there is a need to develop a cost-effective and improved active filtering solution capable of regulating the harmonic profile with optimal placement of scarce active filters. This paper proposes an optimization-based distributed filtering solution to regulate the harmonic profile of an IEEE 33-bus distribution network. The optimization problem formulation is presented in detail, wherein the cost function is minimized and subjected to voltage and bus THD constraints. Firstly, the impact of adding EVs and DGs on the grid's harmonic profile is quantified, which suggests that the grid harmonics are increased by almost 3%. Secondly, the impact of adding distributed active filters on the overall harmonic profile is presented. The detailed simulation results obtained validate the improvement in the harmonic profile, as the post-filter harmonic profile stays below 4.5% for all operating conditions.