A novel unsymmetrical faults analysis for microgrid distribution systems

A novel unsymmetrical faults analysis method with hybrid compensation for microgrid (MG) distribution systems is proposed. The method employs the actual three-phase models to handle unsymmetrical faults. Two matrices, which are built from the topological characteristics of MG distribution networks, and then combined with the proposed hybrid compensation method for injecting branch mismatch currents caused by the fault are used to analyze the branch mismatch currents and bus mismatch voltages directly. An unsymmetrical fault, with appropriate fault boundary conditions can be obtained. The proposed method can then be developed from these two matrices and be used to solve the various types of single or simultaneous unsymmetrical faults. This paper also discusses modeling of a microturbine generation (MTG) as a distributed generator (DG), which delivered for both islanded and grid-connected modes of operation. Test results show that the proposed method is efficient, accurate and easy to program for unsymmetrical faults analysis. (C) 2012 Elsevier Ltd. All rights reserved.