New Passive Islanding Detection Method Based on Cumulative Sum of Change in Voltage Positive Sequence Phase Angle

Abstract

A large non-detection zone near a power balance situation and unwanted distributed generation tripping due to other network events have been the major drawbacks of traditional, passive local islanding detection methods. Usually these traditional methods have also been dependent on the type of the distributed generation unit. In this paper new improved passive, local islanding detection method based on cumulative sum (CS) of change or rate-of-change in voltage positive sequence phase angle is proposed for distributed generation (DG) units and example simulation results are presented. The usage of CS for islanding detection is beneficial because it enables faster islanding detection especially when power unbalance is small and the variable used for islanding detection oscillates after islanding. In addition, the proposed new islanding detection method is not dependent from DG unit type, has smaller non-detection zone (NDZ) and is less susceptible to nuisance tripping as well as can detect islanding faster than the traditional passive islanding detection methods.