Application region of frequency relays for distributed generation

Settings of frequency relays are adjusted to satisfy islanding and frequency tripping requirements. The performance of frequency relays for synchronous based distributed generation (DG) is analyzed using the concept of performance curves. The application region of frequency relays is determined using performance curves which are represented by defining a region in the detection time versus active power imbalance space. The paper examines the sensitivity of the application region to the amount of reactive power mismatch prior to an islanding scenario. Based on computer simulation, the results show that the islandpsilas initial conditions (active and reactive power mismatch) are important factors that should be taken into consideration when designing performance curves for frequency relays.