Islanding Detection of Grid-Connected Photovoltaic Systems Using Active Disturbance-Based Techniques

Abstract

There is increasing demand for electric power generation and attempts are being made to reduce the dependency on use of non-renewable resources for this purpose. Due to this, generation of electric power from solar energy has gained prominence, which has resulted in increase in the number of grid-connected photovoltaic (PV) systems. Increasing number of these systems also needs to comply with the safety and reliability requirements of the existing grid. The possibility of “islanding” of such grid-connected PV systems in particular poses serious threat to the safety of personnel and utility system. In order to prevent such a situation, islanding detection techniques have to be incorporated in grid-connected PV systems. Active islanding detection techniques apply periodic disturbances to the system and measure the corresponding changes observed in the system to detect islanding. Sandia voltage shift and reactive power disturbance methods of islanding detection are discussed in this paper, and their simulated results are also presented for a grid tie inverter system.