FECT

Abstract: For the purpose of reducing carbon dioxide(CO2) emissions in island areas, countermeasures are being studied to operate off-grid micro-grid (MG) systems in a stable manner by increasing the proportion of renewable energy sources (RES) instead of diesel generators (DG). In particular, demonstration and installation of the off-grid MG system which is composed of diesel generator(DG), RES, and energy storage system (ESS) have been implemented in some island areas such as Gapa-do, Gasa-do, and Ulleung-do island. However, many power quality (PQ) problems may be occurred due to an intermittent output of RES in a normal operation of the CVCF inverter-based MG system. This paper performs modeling of 30kW CVCF inverter-based MG system using PSCAD/EMTDC in order to analyze normal operation characteristics in MG system. The simulation results proved that the proposed methods are useful for improving PQ problems such as under-voltage, over-voltage, and unbalanced load in a CVCF inverter-based MG system.

Keywords: Off-grid Micro-grid System, Power Quality Characteristics, Normal Operation, CVCF Inverter, PSCAD/EMTDC S/W.