METHODS FOR ANTI-ISLANDING IN DISTRIBUTED-SOURCE ELECTRICAL POWER GENERATION AND DISTRIBUTION SYSTEMS AND ELECTRICAL SYSTEMS AND APPARATUS USING THE SAME

摘要

A method of detecting an interruption of grid power at an output of an inverter power train coupled to an electrical grid includes generating a reference waveform representative of a power train output current waveform with a current control loop. An abnormal control signal is generated which is synchronized with the grid voltage waveform and out of phase with it, a voltage control loop is connected to the output of the inverter power train, and the voltage control loop has a gain proportional to the inverter power train load impedance. The reference waveform and the abnormal control signal are combined to generate a power train control signal for generating a micro-phase difference between the inverter power train output current waveform and the grid voltage waveform. The inverter power train output is monitored for change and the inverter turn train is turned off in response to a change in the inverter power train output caused by an increase in the inverter power train load impedance due to interruption of the grid power.