Device and method for detecting islanding operation of a static power source

An anti-islanding device for operation of a static power source connected to a grid, comprising:

• means for introducing a small phase angle error that is one of a positive value, a negative value, and a random value for an output voltage of the static power source in each sample step;
• means for detecting an accumulated frequency drift in the output voltage of the static power source away from a grid frequency that is caused in each voltage cycle of the static power source by the introduced small phase angle error upon a loss of the grid;
• and
• an error frequency amplifier for accelerating and enlarging the frequency drift upon the loss of the grid.

An anti-islanding device to operate a static power source connected to a grid, comprising:

• an small phase angle error generator coupled to provide a small phase angle error in the form of a positive value, a negative value and a random value into an output voltage of the static power source;
• an enable signal generator responsive to a clock signal and a grid frequency to provide a first output signal when a magnitude of a frequency change exceeds a first defined value and a second output signal when the magnitude of the frequency change does not exceed the first defined value;
• and
• an error frequency amplifier coupled to amplify the first and the second output signals from the enable signal generator.