The answer is "islanding".What is Islanding?
Islanding is the undesirable condition where a distributed-generation power source, such as a photovoltaic (PV) system, continues to transfer power to the utility grid during a utility outage. When an area of the electrical grid goes down, the power grid instantly stops receiving power. However, islanding can be dangerous if utility workers attempt to restore power to the grid. Because they may believe that the system is completely de-energized when it is not. This can cause damage to equipment or injury to workers.In summary, islanding is a term used to describe an undesirable condition where a distributed-generation power source continues to transfer power to the utility grid during a utility outage.