UNSYMMETRICAL SHORT-CIRCUIT FAULTS ANALYSIS FOR DISTRIBUTION SYSTEM

Abstract

In the near future, most radial distribution systems would become weakly meshed due to the integration of distributed generation and the realization of smart grids. Thus, an efficient and accurate load flow analysis and short circuit fault analysis for unbalanced weakly meshed distribution systems is required. The load flow method and short circuit fault analysis required should be efficient enough to be integrated into smart grid applications. The results of analysis could also be used for real time application in the area of Distribution Automation (DA), such as network optimization, switching, state estimation, fault analysis etc. In this thesis, two matrices based load flow analysis and short circuit fault analysis for unbalanced radial and weakly meshed distribution systems has been described in brief. The investigated solution algorithm is evaluated on 22-bus and 34-bus radial and weakly meshed test system for three - phase balanced (considered as single phase) and unbalanced load flow respectively with very promising result to prove the method efficient and accurate. For short circuit fault analysis, 6-bus and 34-bus radial and weakly meshed test system is used to investigate the algorithm. In this thesis, modelling of transformer is done using the bus-current-injection to branch-current (BIBC) matrix and branch-current to bus-voltage (BCBV) matrix based method and IEEE 4 — bus test feeder is used to investigate the solution.