Abstract: A protection system (80) for a first generator unit (12) connectible by a first switch (24) to a power generating system having at least one additional generator unit with the at least one additional generator unit being connectible in parallel to the first generator unit with the first switch being opened in response to a first control signal to enable the first generator unit to be disconnected from the parallel connection to the at least one additional generator unit in accordance with the invention includes a signal generator (12) for generating a reference signal having a frequency proportional to a frequency of a voltage generated by the first generator unit; a sensor (14) for sensing a common frequency at a point of reference of voltage generated by the generator units of the power generating system; and a controller (14) responsive to the signal generator and the sensor, for calculating a difference between the frequency of the reference signal and the common frequency and for generating the first con