Active anti-islanding protection for distributed generators using impedance measurements.

摘要

Distributed generation is a growing business in electric power systems. Anti-islanding protection of distributed generators (DG) is a significant technical barrier in the industry. A DG while working in conjunction with the main electricity grid must disconnect if the main grid loses power, as it cannot control the voltage and frequency of the power island and poses a significant safety threat to utility workers.;The objective of this research is to investigate a new local active scheme to detect islanding conditions. The technique uses a thyristor controlled short-circuit to inject a disturbance to the power supply system. The supply system impedances are then extracted from the disturbances for determining the islanding condition. Experiments and computer simulations, along with analytical analysis of the proposed method were conducted to assess its effectiveness. The results showed that the method was effective and could be used as a reliable and cost-effective anti-islanding device.