A system for providing anti-islanding protection of a synchronous machine
based distributed generator includes a frequency sensor configured to
generate a generator frequency signal, a bandpass filter configured for
filtering the generator frequency signal, a governor controller
configured for using the filtered frequency signal to generate a power
feedback signal, and a governor summation element configured for summing
the filtered frequency signal, the power feedback signal, and a reference
power to provide an electrical torque signal. Another system includes a
voltage sensor configured to generate a generator terminal voltage
signal, a feedback power calculator configured for generating a reactive
feedback power signal, a bandpass filter configured for filtering the
terminal voltage signal, and a PI controller summation element configured
for summing the filtered terminal voltage signal, the reactive power
feedback signal, and a reference reactive power to provide an error
signal.