This study concerns frequency relays and voltage relays applied to the protection of
synchronous distributed generators operating in reactive power control mode without
a frequency regulation function. The effect of active and reactive powers combination,
load power factor, and reactive power imbalance are investigated for their implication
for the anti-islanding setting of the frequency relay. Results reveal that the effect of
these factors must be considered when setting the relay for islanding detection. For
the voltage relay, results reveal that the effect of active and reactive powers
combination, load power factor, and active power imbalance must be considered when
setting the relay for islanding detection. The effect of multi-stage tripping on the
frequency relay ability to detect island was also investigated. Results show that multistage
tripping can improve the anti-islanding performance of the frequency relay.Electrical EngineeringM. Tech. (Electrical Engineering
