Harmonic Analysis in Distribution System Planning

Ashwini H. K., Mrutyunjay Mohanty, C. R. Sharada Prasad

Abstract: This thesis describes evaluating size of distribution generators in distribution systems so that voltage harmonic distortions at all the buses in a system are within IEEE 519 limits. The proposed methods are developed for two types of evaluation. One for planning stage and other for the existing distribution feeder. In the first type, typical load patterns are considered for the evaluation of DG size and in the second type, network structures of distribution systems, equivalent current injection formulation and the forward/backward sweep based harmonic load flow are used for evaluating the DG Size. Results show that, capacity of distribution generators will be more when they are connected near the substation. Distortion in voltage increases as the distance of DG from substation increases. Obtained results are validated with MATLAB and MiPOWER results.

Keywords: Distributed Generator DG, Total Harmonic Distortion THD, Harmonic Limits, Backward/Forward Sweep