Ferroresonance After Islanding of Synchronous Machine-Based Distributed Generation

This paper reports on ferroresonance phenomenon in distribution networks after the islanding of a distributed generation (DG) unit. Five coupling transformer configurations in synchronous machine-based DG are used to analyze and discuss occurrences of ferroresonance. PSCAD/EMTDC software was used to simulate the various configurations to collect data for analysis. Chaos theory was used to analyze the simulation results in a MATLAB environment in order to understand the type of ferroresonance present. This paper supports that synchronous machine-based DG units could be highly prone to occurrence of ferroresonance phenomenon after islanding with differences observed among the five configurations studied. This paper confirms that a grounded-wye/delta connection is highly prone to ferroresonance and a delta/grounded-wye connection avoids ferroresonance when a DG unit becomes an island.