A detection algorithm for islanding-prevention of dispersed consumer-owned storage and generating units

Summary form only given as follows. One of critical concerns in the operation of grid-connected dispersed generating units is the occurrence of islanding. It is known that the islanding may pose hazards to utility personnel and complicate the orderly reconnection of the grid. Hence, in this paper, a new algorithm based on the monitoring of the change in δf/δP_L to detect the islanding is proposed. By the proposed method, a detection index can be evaluated that serves as a useful reference to activate the protective relays. This approach has been applied to investigate different scenarios, including the loss of grid and the parallel operation. Effects of load change and power-quality disturbances to the detection performance are also examined. From these test results, they help solidify the feasibility and effectiveness of the approach for the applications considered.