Unintentional Islanding of Distributed Generation—Operating Experiences From Naturally Occurred Events

This paper presents original records of distributed-generation unintentional islanding events in three categories. The islands were formed by naturally occurred faults without the transfer trip initiated to generation facilities. Hydraulic, natural gas, and wind generators were involved in the events. The records exemplify important issues in DG anti-islanding planning, such as coordination with underfrequency (or undervoltage) load shedding, reactive power compensation, generation-to-load ratio, reclosing coordination, etc. The events reported in this paper can serve as first-hand references in applying IEEE Standard 1547 to distributed generation anti-islanding planning and operation.