Method of detecting islanding operation for PV power conditioning subsystem, based on Phase-Locked Loop

This paper proposes a detection system of islanding operation in the power conditioner (PCS) and describes the design of control system and operating characteristics. The PCS is required to have a function which detects the islanding operation to stop the system operation. Various methods for detecting the islanding operation have been developed and commercialized. In the conventional method, it is impossible to design quantitatively the response characteristic for detection, depending on power factor control characteristic and load characteristic. The proposed detection method is configured, based on the phase-locked loop (PLL) which performs the power factor control. A control model of the detection system including the load characteristic is derived for designing by using this model. The validity and operating characteristics of the control model are demonstrated by means of simulation and experiments.