CENTRALIZED ISLANDING PROTECTION FOR DISTRIBUTED RENEWABLE ENERGY GENERATORS

摘要

A device and method is disclosed for providing anti-islanding protection for an electrical grid-tied power converter, which is autonomous to the operation of the power converter. The device can protect any number of paralleled power converters and can independently determine if an islanding condition exists. The method involves actively perturbing the electrical grid at a common point of coupling between converter and grid, observing the effect of the perturbation, comparing the perturbed and non-perturbed grid characteristics and disconnecting the converter from the grid if a run-on or islanding condition is indicated. Perturbation is accomplished switching a reactive load or loads onto the grid or by changing a transformer tap connection at the point of common coupling.;The invention is targeted for use in solar photovoltaic power plants which have a number of distributed DC-to-AC power converters. The invention eliminates the interaction of anti-islanding algorithms between multiple power converters, determines islanding conditions with a greater degree of certainty, reduces current distortion over prior art anti-islanding methods and provides a least-cost anti-islanding solution for systems with distributed power converters.